JP2004340195A - Cylinder for fluid pressure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To widen the working range of a locking mechanism provided on a cylinder for fluid pressure. <P>SOLUTION: A cylinder body 42 retains a main piston 21 fixed to a piston rod 19 so as to reciprocate and is partitioned into a first pressure chamber 43 and a second pressure chamber 44. Two locking blocks 52, 53 having tapered surface 52a, 53a are mounted on the piston rod 19 so as to be shifted in the longitudinal direction of the piston rod 19. Two locking pistons 26, 36 having tapered surfaces 26c, 36c corresponding to the respective tapered surfaces 52a, 53a are fixed to the cylinder body 42 at a foremost position approached toward the piston rod 19 and a rearmost position separated from the locking blocks 52, 53 so as to reciprocate and to be shifted in the longitudinal direction of the piston rod 19. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic cylinder for reciprocating a piston rod by a fluid pressure such as air pressure, and more particularly to a technique 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 carriage circulates 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. A hydraulic cylinder is often used as a drive source for swinging the clamp arm, and compressed air is supplied to the hydraulic cylinder by connecting an air pipe to the carrier. However, since the carrier moves between the work stages, it is necessary to remove the air pipe from the carrier when moving. That is, it is required to fix the panel material to the fluid pressure cylinder at the intermediate work stage where the transporting trolley moves even in a situation where the supply of the compressed air is cut off.
[0004]
In order to satisfy this demand, a fluid pressure cylinder having a lock mechanism for restricting expansion and contraction of a piston rod that swings a clamp arm has been developed. As such a fluid pressure cylinder, for example, a lock piston that is movable in the radial direction of the piston rod is provided, and the compressed air is cut off by engaging the lock piston into an engagement groove of the piston rod by a spring force. There is a fluid pressure cylinder that regulates the release operation of the clamp arm even in the closed state.
[0005]
[Patent Document 1]
JP-A-4-283034 (page 4, FIG. 7)
[0006]
[Problems to be solved by the invention]
However, in a hydraulic cylinder in which a lock piston bites into an engagement groove of a piston rod, it is necessary to arrange the lock piston and the piston rod which moves in a predetermined position when operating the lock mechanism. That is, when the panel material and the clamp arm are brought into contact with each other, it is necessary to make the distal end of the lock piston face the engagement groove of the piston rod. It is difficult to maintain the clamped state because the tip of the rod cannot bite into the engagement groove of the piston rod.
[0007]
An object of the present invention is to extend the operating range of a lock mechanism provided in a hydraulic cylinder.
[0008]
[Means for Solving the Problems]
A fluid pressure cylinder according to the present invention includes a cylinder body accommodating a main piston fixed to a piston rod in a reciprocating manner, a lock block assembled to the piston rod and having an inclined surface, and a pressing surface corresponding to the inclined surface. A plurality of lock pistons attached to the cylinder body so as to be reciprocally movable between a forward limit position approaching the piston rod and a retreat limit position away from the lock block. Are mounted so as to be shifted from each other in the longitudinal direction of the piston rod, and each of the plurality of pressing surfaces comes into contact with the inclined surface under different movement positions of the piston rod.
[0009]
The fluid pressure cylinder of the present invention includes a cylinder body that accommodates a main piston fixed to the piston rod in a reciprocating manner, a plurality of lock blocks each having an inclined surface, and being assembled to the piston rod so as to be displaced in the longitudinal direction. A plurality of locks provided on the cylinder body so as to be reciprocally movable between a forward limit position approaching the piston rod and a retreat limit position separated from the lock block, the pressing surfaces corresponding to the respective inclined surfaces. And a plurality of the lock pistons are mounted to be shifted from each other in a longitudinal direction of the piston rod, and each of the plurality of pressing surfaces corresponds to the inclined surface under a different movement position of the piston rod. Contact with
[0010]
The fluid pressure cylinder according to the present invention is characterized in that a plurality of the lock pistons are attached to the cylinder body so as to be adjacent to each other in a longitudinal direction of the piston rod.
[0011]
The hydraulic cylinder according to the present invention is characterized in that a plurality of the lock pistons are attached to the cylinder main body in a circumferential direction of the piston rod.
[0012]
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.
[0013]
According to the present invention, since each of the pressing surfaces of the lock piston is brought into contact with the inclined surface of the lock block under different moving positions of the piston rod, it is possible to avoid increasing the size of the fluid pressure cylinder and lock the hydraulic cylinder. The stroke amount of the piston rod accompanying the movement of the piston can be increased.
[0014]
Thereby, the operating range of the lock piston can be expanded, and, for example, when clamping a work using a fluid pressure cylinder, the fluid pressure cylinder can be widely used for various works having different thickness dimensions.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
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 St1 to the last work stage Stn. At the first work stage St1, the panel material forming the vehicle body is carried into the transport trolley 10 as the work W, and at the final work stage Stn, 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.
[0017]
FIG. 2 is a front view showing the clamp mechanism 12 of FIG. 1, and a hydraulic cylinder 13 according to an embodiment of the present invention is assembled to the clamp mechanism 12. The carrier 10 is provided with a support 14 for supporting the work W, and a clamp arm 15 for clamping the work W is mounted on the support 14 so as to swing about a pin 16. A hydraulic cylinder 13 is swingably mounted on the support 14 via a pin 18 at a portion of a clevis 17 fixed to the hydraulic cylinder 13, and a piston rod 19 of the hydraulic cylinder 13 connects a pin 20 to the clamp arm 15. Are connected via When the piston rod 19 moves in a forward direction with a predetermined stroke, that is, in a direction protruding from the inside of the fluid pressure cylinder 13, the clamp arm 15 clamps the work W.
[0018]
FIG. 3 is a sectional view showing the fluid pressure cylinder 13 of FIG. As shown in FIG. 3, the hydraulic cylinder 13 includes a cylinder tube 22 in which a main piston 21 is reciprocally movable in the axial direction, and a lock case 23 attached thereto. A block accommodating portion 24 and two lock piston accommodating portions 25 and 35 extending in the radial direction are provided. An end cover 40 is attached to an end of the cylinder tube 22, and a rod cover 41 is attached to an end of the lock case 23. A cylinder body 42 is formed by the cylinder tube 22, the lock case 23, the end cover 40, and the rod cover 41.
[0019]
The cylinder tube 22 and the lock block housing portion 24 are partitioned into a first pressure chamber 43 and a second pressure chamber 44 by the main piston 21 housed in the cylinder tube 22. A supply / discharge port 45 communicating with the first pressure chamber 43 is formed on the end cover 40, and a supply / discharge port 46 communicating with the second pressure chamber 44 is formed on the rod cover 41. When compressed air as a working fluid is supplied from the supply / discharge port 45 to the first pressure chamber 43, the main piston 21 moves forward toward the rod cover 41, while compressed air is supplied from the supply / discharge port 46 to the second pressure chamber 44. Then, the main piston 21 moves backward toward the end cover 40.
[0020]
The main piston 21 has a first disk 47 and a second disk 48 both having cylindrical portions 47a and 48a. A sealing material 49 is provided on the first disk 47, and a female thread 48b is formed on the cylindrical portion 48a of the second disk 48. An annular magnet 50 is interposed between the first disk 47 and the second disk 48, and the position of the main piston 21 can be detected via the magnet 50 by a sensor (not shown) provided on the cylinder tube 22. It has become.
[0021]
FIG. 4 is a perspective view showing a part of the rod unit 51. As shown in FIGS. 3 and 4, the piston rod 19 assembled to the main piston 21 includes a large-diameter rod portion 19a protruding from the cylinder body 42 and a small-diameter rod portion 19b housed in the cylinder body 42. A male screw 19c is formed at the tip of the small diameter rod portion 19b. In the lock block housing portion 24, two lock blocks 52, 53 each having a tapered surface 52a, 53a, which is an inclined surface, and two cylindrical spacers 54, 55 are alternately arranged. ing. The small-diameter rod portion 19b of the piston rod 19 is passed through the through-holes of the lock blocks 52, 53 and the spacers 54, 55. Two disks 48 are screwed together.
[0022]
As described above, the main piston 21, the lock blocks 52, 53, and the spacers 54, 55 are assembled to the piston rod 19, and the rod unit 51 is formed by the piston rod 19, the main piston 21, the lock blocks 52, 53, and the spacers 54, 55. Is formed. One end of the rod unit 51 is supported reciprocally by the rod cover 41, and the other end is supported reciprocally by the cylinder tube 22 via the main piston 21. By the control of the supply and discharge of compressed air to and from the second pressure chamber 44 and 43, they move integrally in the axial direction.
[0023]
The two lock piston accommodating portions 25, 35 are respectively formed by cylinders 25a, 35a and head covers 25b, 35b for closing the cylinders. Lock pistons 26, 36 are housed in the cylinders 25a, 35a, and the lock pistons 26, 36 are reciprocally movable in the radial direction of the piston rod 19. The lock pistons 26, 36 generate thrust opposing the spring forces of the lock spring members 27, 37 and the spring chambers 28, 38 in which the lock spring members 27, 37 are stored in the lock piston housing portions 25, 35. Lock release pressure chambers 29 and 39 are formed.
[0024]
The lock pistons 26, 36 which are respectively attached to the cylinder main body 42 and whose axial centers are arranged so as to be shifted from each other in the longitudinal direction of the piston rod 19, are provided with flange portions 26a, 36a and spring receiving holes 26b, 36b. It is formed in a cylindrical shape. Locking spring members 27 and 37 are incorporated in the spring receiving holes 26b and 36b, and the locking spring members 27 and 37 are held in the spring chambers 28 and 38 by the spring receiving holes 26b and 36b and the head covers 25b and 35b. I have. Further, tapered rod portions 26d, 36d having tapered surfaces 26c, 36c, which are pressing surfaces, are formed at the tips of the lock pistons 26, 36, and the taper angle of the tapered surfaces 26c, 36c is about 60 °. Is formed. The tapered surfaces 52a, 53a of the lock blocks 52, 53 facing the tapered surfaces 26c, 36c are formed at an obtuse angle of about 120 °.
[0025]
When compressed air is supplied from the supply / discharge port 46 to the second pressure chamber 44, the communication holes 25 c, 35 c formed in the cylinders 25 a, 35 a communicate with the unlocking pressure chambers 29, 39 and the second pressure chamber 44. Via this, the compressed air in the second pressure chamber 44 is supplied to the unlocking pressure chambers 29 and 39. By the thrust from the compressed air supplied to the unlocking pressure chambers 29, 39, the lock pistons 26, 36 are compressed to the lock blocks 52, 53, that is, the retracted position away from the rod unit 51 while compressing the locking spring members 27, 37. The lock pistons 26, 36 are stopped by the flange portions 26a, 36a of the lock pistons 26, 36 contacting the head covers 25b, 35b. On the other hand, when the compressed air in the unlocking pressure chambers 29, 39 is discharged from the supply / discharge port 46, the lock pistons 26, 36 are moved toward the piston rod 19, that is, the rod unit 51 by the spring force of the locking spring members 27, 37. And the downward movement is stopped when the flange portions 26a and 36a of the lock pistons 26 and 36 come into contact with the stoppers of the cylinders 25a and 35a.
[0026]
The screw holes 26e, 36e are formed extending from the spring receiving holes 26b, 36b of the lock pistons 26, 36, and the screw holes 26e, 36e are used when the lock pistons 26, 36 are manually moved. . Screw members 25d, 35d are mounted in the through holes formed in the center portions of the head covers 25b, 35b as plugs for shutting off the spring chambers 28, 38 from the outside, and when the lock pistons 26, 36 are manually moved. , A rod member (not shown) having a male screw formed at the tip is inserted into the through hole from the outside with the screw members 25d and 35d removed, and screwed to the lock pistons 26 and 36 via the screw holes 26e and 36e. Let it. Thereby, the lock pistons 26 and 36 can be moved to the retreat limit position and the forward limit position from outside via the rod member.
[0027]
Subsequently, a flow path for supplying compressed air to the first pressure chamber 43, the second pressure chamber 44, and the unlocking pressure chambers 29 and 39 will be described. FIG. 5 is a sectional view showing the structure of the rod cover 41 along the line AA in FIG. As shown in FIG. 5, three supply / discharge ports 46 are formed in the rod cover 41 in the radial direction, and a supply / discharge pipe is connected to any one of the supply / discharge ports 46 according to a use situation. . This pipe 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 46 by the switching operation of the flow path switching valve, and compressed air is supplied from the supply / discharge port 46. Is discharged. The unused supply / discharge port 46 is closed by a plug 56.
[0028]
A guide cylinder 57 is incorporated inside the rod cover 41, and a flow channel 58 communicating with the three supply / discharge ports 46 is formed on the outer peripheral surface of the guide cylinder 57. A communication hole 60 that communicates with the flow channel groove 59 formed on the inner peripheral surface of the guide cylinder 57 is formed. A needle 61 serving as a throttle mechanism is mounted on the rod cover 41 so as to enter the communication hole 60, and the needle 61 having an external thread 61 a formed on the outer peripheral surface thereof changes the flow path cross-sectional area of the communication hole 60. And the flow rate of the compressed air passing through the communication hole 60 can be controlled. The compressed air guided to the flow channel 59 through the communication hole 60 is supplied to the second pressure chamber 44 and the unlocking pressure chambers 29 and 39.
[0029]
FIG. 6 is a side view showing the fluid pressure cylinder 13 from the direction of arrow B in FIG. As shown in FIG. 6, a plurality of supply / discharge ports 45 communicating with the first pressure chamber 43 are formed in the end cover 40, and one of the supply / discharge ports 45 is connected to one of the supply / discharge ports 45 in accordance with a use state. Piping 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 45 by the switching operation of the flow path switching valve. The compressed air is discharged from the port 45. Therefore, the supply / discharge control of the compressed air to / from the first pressure chamber 43 through the supply / discharge port 45 can be performed. The unused supply / discharge port 45 is closed by the plug 62.
[0030]
Next, a process of retreating the rod unit 51 by supplying compressed air to the second pressure chamber 44 and a process of moving the rod unit 51 forward by supplying compressed air to the first pressure chamber 43 will be described.
[0031]
First, when the rod unit 51 is moved backward, the compressed air in the first pressure chamber 43 is discharged and the compressed air is supplied to the second pressure chamber 44, so that a thrust in the backward direction is applied to the rod unit 51. Here, since the second pressure chamber 44 communicates with the unlocking pressure chambers 29 and 39 via the communication holes 25c and 35c, the compressed air supplied to the second pressure chamber 44 is locked via the communication holes 25c and 35c. It is also supplied to the release pressure chambers 29 and 39.
[0032]
The compressed air supplied to the unlocking pressure chambers 29, 39 applies a thrust to the flange portions 26a, 36a of the lock pistons 26, 36 in the upward direction for compressing the locking spring members 27, 37, and the second pressure chamber 44. A thrust is also applied to the tapered rod portions 26d, 36d in the ascending direction by the compressed air supplied to the first and second portions. The lock pistons 26, 36 to which the thrust has been applied in this way start moving upward away from the lock blocks 52, 53, and rise to the retreat limit positions where they come into contact with the head covers 25b, 35b. Since the lock pistons 26 and 36 are retracted from the retreating movement paths of the lock blocks 52 and 53 by this upward movement, the tapered surfaces 52a and 53a of the lock blocks 52 and 53 and the tapered surfaces 26c and 36c of the lock pistons 26 and 36 are formed. Contact is avoided, and the rod unit 51 can be moved backward. The pressure receiving areas of the lock pistons 26 and 36 are set to an area capable of generating a thrust against the spring force of the lock spring members 27 and 37.
[0033]
Next, when the rod unit 51 is moved forward, the compressed air in the second pressure chamber 44 is discharged and the compressed air is supplied to the first pressure chamber 43, so that a thrust in the forward direction is applied to the rod unit 51. At this time, since the pressure in the second pressure chamber 44 is in a reduced state, the lock pistons 26 and 36 are in a state of being lowered to the forward limit position by the spring force of the locking spring members 27 and 37. That is, the lock pistons 26 and 36 are arranged in front of the lock blocks 52 and 53.
[0034]
When the lock blocks 52, 53 that move forward contact the lock pistons 26, 36, the tapered surfaces 52b, 53b formed on the forward side of the lock blocks 52, 53 come into contact with the tips of the tapered rod portions 26d, 36d. Will do. However, since the tapered surfaces 52b, 53b of the lock blocks 52, 53 are formed at an acute angle, the lock pistons 26, 36 slide upward on the tapered surfaces 52b, 53b toward the retreat position by contact. After the lock pistons 26 and 36 that move upward exceed the maximum outer diameter portions of the lock blocks 52 and 53, the lock pistons 26 and 36 are guided by the tapered surfaces 52a and 53a on the retreating side of the lock blocks 52 and 53, and move toward the forward limit position again. Move down.
[0035]
As described above, when the rod unit 51 is moved forward, the lock pistons 26, 36 are arranged in the forward movement path of the lock blocks 52, 53. However, the lock pistons 26, 36 have the tapered surfaces 52b, Since the rod unit 51 is pushed up by 53b and gets over the lock blocks 52 and 53, the rod unit 51 can move forward.
[0036]
The compressed air in the second pressure chamber 44 is discharged from the supply / discharge port 46 as the main piston 21 moves forward, but the discharge flow from the supply / discharge port 46 is restricted by the needle 61 provided in this discharge path. can do. Thus, a back pressure can be generated in the second pressure chamber 44 in accordance with the moving speed of the main piston 21, and the back pressure can assist the upward movement of the lock pistons 26 and 36.
[0037]
Hereinafter, an operation process of the hydraulic cylinder 13 in which the lock mechanism operates will be described. 7 (A) to 8 (B) are enlarged sectional views showing a part of the fluid pressure cylinder 13, and FIGS. 7 (A), 7 (B), 8 (A), 8 (B). 2 shows the operation process of the lock mechanism.
[0038]
When the rod unit 51 that moves forward by the thrust from the first pressure chamber 43 moves forward beyond the position shown in FIG. 7A, the lock piston 26 on the end cover 40 starts moving downward. At this time, a clearance C1 is formed between the main piston 21 and the lock block housing portion 24.
[0039]
Subsequently, as shown in FIG. 7B, when the lock piston 26 moves downward, the tapered surfaces 26c and 52a of the lock piston 26 and the lock block 52 come into contact with each other. The unit 51 is pushed out in the forward direction. On the other hand, the lock piston 36 on the rod cover 41 side is maintained in a state where its lower end surface is in contact with the maximum diameter portion of the lock block 53. That is, the rod unit 51 is pushed out by one lock piston 26.
[0040]
Further, as shown in FIG. 8A, when the rod unit 51 is pushed out by the lock piston 26 and the moving position of the rod unit 51 is displaced in the forward direction, the lock piston 36 on the rod cover 41 side and the lock block 53 are moved. Since the tapered surfaces 36c and 53a come into contact with each other, the rod unit 51 is further pushed in the forward direction as the lock piston 36 moves downward as shown in FIG. 8B.
[0041]
Thus, the rod unit 51 is pushed out by the stroke S1 shown in FIG. 8A by the downward movement of the lock piston 26 on the end cover 40 side, and then the rod unit 51 is pushed by the downward movement of the lock piston 36 on the rod cover 41 side. The unit 51 is pushed out to the stroke S2 shown in FIG. Then, since the tapered rod portion 36 d enters the retracting direction of the lock block 53, the retracting movement of the rod unit 51 is restricted until compressed air is supplied to the unlocking pressure chambers 29 and 39.
[0042]
That is, when the rod unit 51 moves forward to the position shown in FIG. 7A by the thrust from the first pressure chamber 43, the lock pistons 26, 36 contact the tapered surfaces 52a, 53a of the lock blocks 52, 53. Since the rod unit 51 is moved downward while being pushed, the rod units 51 are further pushed out in the forward direction by the lock pistons 26 and 36, and the movement in the backward direction is restricted.
[0043]
The spring force of the locking spring members 27, 37 for lowering the lock pistons 26, 36 is applied to the lock block via the tapered surfaces 26c, 36c formed at acute angles and the tapered surfaces 52a, 53a formed at obtuse angles. As a result, the spring force of the locking spring members 27 and 37 is increased and transmitted to the rod unit 51.
[0044]
Next, the operation of the clamp mechanism 12 including the fluid pressure cylinder 13 will be described together with the movement of the carrier 10 on the vehicle body assembly line. First, as shown in FIG. 2, the fluid pressure cylinder 13 incorporated in the carrier 10 causes the clamp arm 15 to swing toward the workpiece W by moving the piston rod 19 of the fluid pressure cylinder 13 forward. The work W mounted on the support base 14 is fastened and fixed, while the piston rod 19 is moved backward to release the work W from fastening.
[0045]
As shown in FIG. 2, a supply / discharge joint 63 provided on the carrier 10 for supplying compressed air to the fluid pressure cylinder 13 has two supply / discharge hoses connected to the supply / discharge ports 45 and 46, respectively. 64, 65 are connected to supply compressed air to the first pressure chamber 43, the second pressure chamber 44, and the unlocking pressure chambers 29, 39, and to supply compressed air from the pressure chambers 29, 39, 43, 44. The discharge is performed via the supply / discharge joint 63.
[0046]
As shown in FIG. 1, a supply / discharge joint 66 connected to the supply / discharge joint 63 of the transport vehicle 10 is provided on the first work stage St1, and the supply / discharge joint 66 is connected to an air pressure source (not shown). It is connected via a path switching valve. These supply / discharge joints 63 and 66 are connected to each other when the transporting trolley 10 is disposed on the first work stage St1, so that compressed air is supplied from the air pressure source to the pressure chambers 29, 39, 43 and 44. The air in the pressure chambers 29, 39, 43, and 44 can be discharged to the outside.
[0047]
When the transporting trolley 10 is moved to the first work stage St1, compressed air is supplied from the supply / discharge port 46 to the second pressure chamber 44 via the supply / discharge joints 63, 66 connected to each other. The air in the first pressure chamber 43 is discharged from the supply / discharge port 45. By such supply / discharge control, the lock pistons 26 and 36 move upward, and the movable rod unit 51 moves backward. When the rod unit 51 is retracted into the cylinder main body 42, the clamp arm 15 is opened upward by the retreat movement, and the transport carriage 10 is brought into the work W carrying state.
[0048]
Subsequently, when the work W is carried into the support platform 14 of the carrier 10 by a carrier device (not shown), the compressed air supplied to the second pressure chamber 44 via the supply / discharge joints 63 and 66 is supplied and discharged. While being discharged from the port 46, compressed air is supplied to the first pressure chamber 43 from the supply / discharge port 45. The rod unit 51 moves forward by such supply / discharge control.
[0049]
When the rod unit 51 protrudes from the inside of the cylinder body 42 beyond the position shown in FIG. 7A, the tip of the clamp arm 15 that is closed downward contacts the work W and tightens and fixes the work W. Subsequently, the rod units 51 are pushed out in the forward direction by the sequentially descending lock pistons 26 and 36, and the backward movement of the rod units 51 is restricted.
[0050]
As described above, in the first work stage St1, the work W fastened and fixed on the support base 14 is first fastened by the forward movement of the rod unit 51 accompanying the supply of the compressed air to the first pressure chamber 43, and subsequently locked. The rod unit 51 is pushed out by the downward movement of the pistons 26 and 36, and is further tightened and fixed. In addition, the thrust from the first pressure chamber 43 is applied to the rod unit 51 pushed out by the lock pistons 26 and 36 in the forward direction together with the spring force, so that a high fastening force to the work W is exerted.
[0051]
Since the maximum stroke amount of the rod unit 51 pushed out by the lock pistons 26 and 36 is the stroke S2 as shown in FIG. 8B, the main stroke when the tip of the clamp arm 15 contacts the work W is reduced. If the stop position of the piston 21 is within the range of the stroke S2, it is possible to securely tighten and fix other works having different thickness dimensions.
[0052]
When the work such as spot welding is completed in the first work stage St1 to which the work W is fixed, the transport trolley 10 is moved to the next work stage St2. When the carrier 10 is moved, the connection of the supply / discharge joints 63 and 66 connected to each other is released, and the compressed air in the first pressure chamber 43 is discharged. Since the backward movement is restricted, the clamped state of the work W is maintained while maintaining a high tightening force.
[0053]
As described above, even when the thrust from the first pressure chamber 43 cannot be obtained, the rod unit 51 does not move backward and the tightening force of the rod unit 51 does not decrease. The workpiece W is kept in a clamped state even when vibration or impact is applied to the workpiece W.
[0054]
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 Stn is completed, the work W is carried out of the body assembly line. As shown in FIG. 1, a supply / discharge joint 67 similar to the above-described supply / discharge joint 66 is provided on the final work stage Stn, and when the transport vehicle 10 is disposed on the final work stage Stn, the supply / discharge joint is provided. Since the joints 63 and 67 are connected to each other, supply / discharge control of the pressure chambers 29, 39, 43, and 44 can be performed.
[0055]
In the final work stage Stn, compressed air is supplied from the supply / discharge port 46 to the second pressure chamber 44 and the unlocking pressure chambers 29, 39, while air in the first pressure chamber 43 is discharged from the supply / discharge port 45. Therefore, the lock pistons 26 and 36 move upward with the pressure increase in the unlocking pressure chambers 29 and 39, and the rod unit 51 moves backward with the pressure increase in the second pressure chamber 44. When the clamp arm 15 is opened upward by the retreating movement of the piston rod 19, the transport carriage 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 St1.
[0056]
FIG. 9 is a plan view showing a hydraulic cylinder 70 according to another embodiment of the present invention, and FIG. 10 is a side view showing the hydraulic cylinder 70 from the direction of arrow A in FIG. FIG. 11 is a sectional view showing the fluid pressure cylinder 70 along the line AOA in FIG. 9 to 11, the same members as those shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.
[0057]
In the fluid pressure cylinder 13 of FIG. 3, the two lock piston accommodating portions 25 and 35 arranged adjacently in the longitudinal direction are arranged adjacently in the fluid pressure cylinder 70 of FIG. 9 in the circumferential direction. ing. As shown in FIG. 10, the two lock piston housings 25 and 35 forming the lock case 71 are provided in a substantially V shape so as to extend in the radial direction of the lock block housing 72. Further, as shown in FIG. 11, one lock block 53 and a spacer 74 are incorporated in the small-diameter rod portion 73a of the piston rod 73, and the rod has a shorter length than the rod unit 51 of FIG. A unit 75 is formed. The two lock pistons 26 and 36 that sequentially contact one lock block 53 are arranged with their axes shifted from each other in the longitudinal direction of the piston rod 73.
[0058]
The fluid pressure cylinder 70 can move the rod unit 75 forward and backward by supplying compressed air from the supply / discharge ports 45 and 46, similarly to the fluid pressure cylinder 13 in FIG. When the rod unit 75 moves forward by a predetermined stroke, the two lock pistons 26 and 36 can be moved downward to the forward limit position.
[0059]
When the two lock pistons 26, 36 move downward to the forward limit position, first, the lock piston 26 on the end cover 40 moves downward toward the forward limit position shown in FIG. I do. Next, since the lock block 53 moved forward is disposed below the lock piston 36 on the rod cover 41 side, the lock piston 36 further moves the lock block 53 further toward the forward limit position shown in FIG. Move down. The portion of the taper surface 53a of the lock block 53 where the taper surface 26c of the lock piston 26 contacts, and the portion of the taper surface 53a of the lock block 53 where the taper surface 36c of the lock piston 36 contacts are different from each other. Has become.
[0060]
By arranging the lock pistons 26 and 36 in this manner, a plurality of lock pistons 26 and 36 can be brought into contact with one lock block 53, so that the length of the rod unit 75 can be reduced and the length of the lock block housing 72 can be reduced. The size can be reduced. Thereby, the size reduction of the fluid pressure cylinder 70 can be achieved.
[0061]
FIG. 12 is a front view showing a clamp mechanism 12 provided with a fluid pressure cylinder 80 according to another embodiment of the present invention. 12, the same members as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.
[0062]
The clamp mechanism 12 shown in FIG. 2 closes the clamp arm 15 by the forward movement of the piston rod 19, whereas the clamp mechanism 12 shown in FIG. 12 closes the clamp arm 15 by the backward movement of the piston rod 19. . The lock case 23 of the fluid pressure cylinder 80 is provided at a rear portion of the cylinder body 42, and the cylinder tube 22 is provided at a front portion of the cylinder body 42. A piston rod 81 connected to the clamp arm 15 is mounted on one end of the main piston 21, while a piston rod 19 with lock blocks 52 and 53 is mounted on the other end of the main piston 21. The compressed air supplied to the first pressure chamber 43 defined by the cylinder tube 22 applies a thrust to the piston rods 19 and 81 in the retreating direction on the rod cover 41 side, and is supplied to the second pressure chamber 44. By the compressed air, a thrust is applied to the piston rods 19 and 81 in the forward direction on the rod cover 82 side.
[0063]
The fluid pressure cylinder 80 can move the piston rod 81 forward and backward by supplying compressed air from the supply / discharge ports 45 and 46, similarly to the fluid pressure cylinder 13 in FIG. Further, when the piston rod 81 retreats by a predetermined stroke, the two lock pistons 26, 36 are moved down to the forward limit position, the piston rod 81 is further retracted, and the work W is held in a clamped state. can do.
[0064]
As described above, the fluid pressure cylinders 13, 70, 80 of the present invention allow the tapered surfaces 26c, 36c of the lock pistons 26, 36 to be moved under different movement positions of the piston rods 19, 73, 81, respectively. Since the taper surfaces 52a and 53a of the lock blocks 52 and 53 are brought into contact with each other, the stroke amount of the piston rods 19, 73 and 81 on which the lock mechanism operates can be increased. Accordingly, when the fluid pressure cylinders 13, 70, 80 are applied to the clamp mechanism, it is possible to widely correspond to various works W having different thickness dimensions. For example, in the case of the fluid pressure cylinder 13 shown in FIG. 3, since the lock mechanism can be operated within the range of the stroke S2 shown in FIG. 8B, various works W having different thickness dimensions can be operated within this range. Clamping can be performed reliably.
[0065]
Further, as shown in FIG. 8B, the clamping of the work W may be completed by lowering the two lock pistons 26 and 36 to the forward limit position. As shown in FIG. 8A, the clamping of the work can be completed in a state where only one lock piston 26 has moved down to the forward limit position.
[0066]
Further, since the hydraulic cylinders 13, 70, 80 of the present invention use a plurality of lock pistons 26, 36, the individual lock pistons 26, 36 can be downsized, that is, the hydraulic cylinders 13, 70, 80 can be downsized. In addition to achieving the realization, the taper angles of the tapered surfaces 26c, 36c formed on the lock pistons 26, 36 can be set narrow. Thus, the thrust transmitted from the lock pistons 26, 36 to the lock blocks 52, 53 can be increased.
[0067]
Further, when one lock block 53 is pushed in by a plurality of lock pistons 26 and 36 circumferentially adjacent to the piston rod 73 as in a hydraulic cylinder 70 shown in FIGS. In the longitudinal direction can be suppressed.
[0068]
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 13, 70, and 80 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 purposes other than clamping. You can also. Further, the fluid pressure cylinders 13, 70, and 80 are attached to the carrier 10 but may be attached to, for example, a robot arm.
[0069]
Although the illustrated fluid pressure cylinders 13, 70, and 80 use two lock pistons 26 and 36, more lock pistons may be used, and by using three or more lock pistons, The stroke amount of the piston rods 19, 73, 81 accompanying the movement of the lock piston can be further increased.
[0070]
Further, tapered surfaces 26c, 36c, 52a, 53a are formed as pressing surfaces of the lock pistons 26, 36 and inclined surfaces of the lock blocks 52, 53, which are formed by the lock pistons 26, 36 and the lock blocks 52, 53. This is to ensure a proper contact state even when the rotation is performed, and a simple slope may be formed as long as the lock pistons 26 and 36 and the lock blocks 52 and 53 are treated to prevent rotation.
[0071]
Although air is used as the working fluid when operating the fluid pressure cylinders 13, 70, 80, it goes without saying that other fluids may be used.
[0072]
【The invention's effect】
According to the present invention, since each of the pressing surfaces of the lock piston is brought into contact with the inclined surface of the lock block under different moving positions of the piston rod, it is possible to avoid increasing the size of the fluid pressure cylinder and lock the hydraulic cylinder. The stroke amount of the piston rod accompanying the movement of the piston can be increased.
[0073]
Thereby, the operating range of the lock piston can be expanded, and, for example, when clamping a work using a fluid pressure cylinder, the fluid pressure cylinder can be widely used for various works having different thickness dimensions.
[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 perspective view showing a rod unit.
FIG. 5 is a cross-sectional view showing a structure of a rod cover taken along line AA of FIG. 3;
FIG. 6 is a side view showing the fluid pressure cylinder from the direction of arrow B in FIG. 3;
FIG. 7A is a cross-sectional view showing a part of the hydraulic cylinder in which a lock piston has been moved to a retreat limit position, and FIG. 7B is a sectional view when the lock piston moves from a retreat limit position to a forward limit position. It is sectional drawing which shows a part of fluid pressure cylinder.
FIG. 8A is a cross-sectional view showing a part of the hydraulic cylinder when the lock piston moves from the retreat limit position to the forward limit position, and FIG. 8B is a sectional view showing the lock piston moved to the forward limit position. It is sectional drawing which shows a part of fluid pressure cylinder.
FIG. 9 is a plan view showing a fluid pressure cylinder according to another embodiment of the present invention.
FIG. 10 is a side view showing the fluid pressure cylinder from the direction of arrow A in FIG. 9;
11 is a sectional view showing the structure of the fluid pressure cylinder along the line AOA of FIG. 10;
FIG. 12 is a front view showing a clamp mechanism provided with a fluid pressure cylinder according to another embodiment of the present invention.
[Explanation of symbols]
10 transport trolley
11 wheels
12 Clamp mechanism
13 Fluid pressure cylinder
14 Support
15 Clamp arm
16 pin
17 Clevis
18 pin
19 Piston rod
19a Large diameter rod
19b Small diameter rod
19c male screw
20 pins
21 Main piston
22 cylinder tube
23 Lock Case
24 Lock block storage
25 Lock piston housing
25a cylinder
25b head cover
25c communication hole
25d screw member
26 Lock piston
26a Flange part
26b Spring receiving hole
26c tapered surface (pressing surface)
26d taper rod
26e screw hole
27 Locking Spring Member
28 Spring Chamber
29 Lock release pressure chamber
35 Lock piston housing
35a cylinder
35b head cover
35c communication hole
35d screw member
36 Lock piston
36a Flange
36b Spring receiving hole
36c tapered surface (pressing surface)
36d taper rod
36e screw hole
37 Lock spring member
38 Spring Chamber
39 Unlocking pressure chamber
40 End cover
41 Rod cover
42 cylinder body
43 1st pressure chamber
44 2nd pressure chamber
45, 46 supply / discharge port
47 First Disk
47a cylindrical part
48 Second Disk
48a cylindrical part
48b female screw
49 Sealing material
50 magnets
51 Rod unit
52,53 lock block
52a, 53a Tapered surface (inclined surface)
52b, 53b Tapered surface
54, 55 spacer
56 plug
57 Guide cylinder
58, 59 Channel groove
60 communication hole
61 Needle
61a male screw
62 plug
63 Supply / discharge joint
64,65 supply / discharge hose
66, 67 supply / discharge joint
70 Fluid pressure cylinder
71 Lock Case
72 Lock block storage
73 piston rod
73a small diameter rod
74 spacer
75 Rod unit
80 Fluid pressure cylinder
81 piston rod
82 Rod cover

Claims (5)

A cylinder body that accommodates a main piston fixed to the piston rod in a reciprocating manner,
A lock block assembled to the piston rod and having an inclined surface;
A plurality of lock pistons having a pressing surface corresponding to the inclined surface, and a plurality of lock pistons attached to the cylinder body so as to reciprocate between a forward limit position approaching the piston rod and a retreat limit position away from the lock block. Have
The plurality of lock pistons are attached to be shifted from each other in the longitudinal direction of the piston rod, and each of the plurality of pressing surfaces contacts the inclined surface under different movement positions of the piston rod. Fluid pressure cylinder. A cylinder body that accommodates a main piston fixed to the piston rod in a reciprocating manner,
A plurality of lock blocks each having an inclined surface and being assembled to the piston rod so as to be shifted in the longitudinal direction,
A plurality of lock pistons, each having a pressing surface corresponding to each of the inclined surfaces, being reciprocally attached to the cylinder body between a forward limit position approaching the piston rod and a retreat limit position away from the lock block. And having
The plurality of lock pistons are attached to be shifted from each other in the longitudinal direction of the piston rod, and each of the plurality of pressing surfaces comes into contact with the corresponding inclined surface under different movement positions of the piston rod. And a hydraulic cylinder. 3. The hydraulic cylinder according to claim 1, wherein the plurality of lock pistons are attached to the cylinder body so as to be adjacent to each other in a longitudinal direction of the piston rod. 3. The hydraulic cylinder according to claim 1, wherein the plurality of lock pistons are attached to the cylinder body in a circumferential direction of the piston rod. The hydraulic cylinder according to any one of claims 1 to 4, wherein the clamp arm is swung by reciprocating movement of the piston rod.

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