JPS63297805A - Cylinder device - Google Patents

Abstract

PURPOSE:To maintain a clamping force even if a fluid pressure is decreased by providing a lock device in a cylinder device for clamping a work etc. in an assembling line and arranging a spring member between a piston and a piston rod tip part. CONSTITUTION:A lock device 11 which regulates any axial movement of a piston 3 is provided on a cylinder device 1, while a spring device 12 is attached on the tip of a piston rod 4. Thus, the tip part of the piston rod 4 presses a load owing to the elastic force of the spring device 12, even when a fluid pressure is by locking the piston 3 by means of the lock device 11. When a work is clamped by this cylinder device 1, therefore, the clamping force can be maintained even if the fluid pressure is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cylinder device operated by fluid pressure, and is used, for example, as a clamp device for clamping a workpiece.

[Prior art and its problems] Clamping devices for clamping workpieces have been frequently used in factory assembly lines (for example, Utility Model Application No. 190478/1983), and as actuators for lamp devices, A cylinder device operated by fluid pressure is used.

In such a cylinder device for a lamp, various devices are provided in order to maintain the clamping force even when the pressure of the fluid pressure source decreases while the workpiece is clamped.

For example, in a cylinder device operated by pneumatic pressure, a pilot is installed in the air flow path to the cylinder chamber to prevent the pressure in the cylinder chamber on the side that generates the clamping force from decreasing even if the pressure of the air pressure source decreases or is disconnected. It is common practice to provide a check valve.

Although this check valve device has a simple structure and is sufficiently effective for a short period of time, it is practically impossible to maintain the clamping force for a long period of time.

In addition, in order to restrict the axial movement of the piston due to a drop in fluid pressure, a locking device that firmly grips the piston rod and locks it by frictional force, or a locking device that engages in the axial direction with a locking recess provided in the piston. A locking device or the like is provided in which a plunger is moved back and forth in the radial direction of the cylinder. However, although such a locking device prevents the piston or piston rod from moving back in the axial direction to some extent, it loses the force to press the workpiece, causing backlash and making it impossible to maintain the clamping force.

[Technical means for solving the problems] In view of the above-mentioned problems, the present invention aims to provide a cylinder device that can maintain clamping force even when fluid pressure decreases. Technical means provide a cylinder device having a cylinder tube, a piston that moves axially in the cylinder tube by fluid pressure, and a piston rod that transmits the axial movement of the piston to a load, in which the axis of the piston is A spring member is provided between the piston and the tip of the piston rod and is elastically deformable in the axial direction, and the tip of the piston rod is connected to the spring member. The piston is biased in the distal direction with respect to the piston.

Note that the tip of the piston rod here refers to a portion that transmits the driving force of the cylinder device to the load, and includes the piston rod itself or a connection device with the load provided at the tip of the piston rod.

[For production]

The piston moves due to fluid pressure, and the piston rod moves accordingly, pressing the load with its tip. When the locking device operates, movement of the piston is restricted, and even if the fluid pressure decreases in this state, the load is pressed by the spring member. When the load is a clamping device, the clamping force is maintained by the pressing force of the spring member.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially sectional front view of the cylinder device 1. FIG.

The cylinder device 1 includes a cylinder tube 2, a piston 3 that reciprocates in the axial direction within the cylinder tube 2, a piston rod 4 connected to the piston 3, and a cylinder tube 2.
a cylinder cover 5.7 for closing both ends of the cylinder cover 5.7, a cover block 6, a locking ring boss 8, a locking ring 9, a locking device 11fll for regulating the axial movement of the piston 3,
and a spring device 12 attached to the tip of the piston rod 4. Note that 5a and 7a are boats for supplying air, and 10 is a mounting hole for mounting the cylinder device 1.

FIG. 2 is an enlarged sectional view of the locking device 11.

The lock W111 includes a casing 15 attached to the cover block 6 by bolts 19, a lock piston 13 that reciprocates within the casing 15, and a lock piston 1.
3, a coil spring 16, etc., and the plunger 14 slides inside a bush 6b provided on the cover block 6 and can move in and out of the cylinder chamber 2a.

This locking device 11, when air is not supplied,
The lock piston 13 is pressed downward in the figure by the coil spring 16, and as a result, the plunger 14 protrudes into the cylinder chamber 2a and the locking groove 9 of the locking ring 9
b, and the locking protrusion 9a of the locking ring 9 abuts and locks the plunger 14, thereby restricting movement of the piston 3 and piston rod 4 in the wheel axis direction.

When air is supplied from the cylinder chamber 2a and air pressure is generated in the cylinder chamber 2a, the air passes through the communication hole 6a provided in the cover block 6 and pushes up the lock piston 13, causing the plunger 14 and locking ring 9 to The engagement is released, and the piston 3 and piston rod 4 are free to move in the axial direction, and the piston 3 is moved to the left in the figure by the air pressure in the cylinder chamber 2a.

Furthermore, when the air supply is switched from BO) 5a to BO) 7a with the piston 3 moving to the left stroke end in the figure, the air pressure in the cylinder chamber 2a decreases, and the plunger I4 is moved by the coil spring. cylinder chamber 2 again by 6
As the piston 3 protrudes into the cylinder chamber 2b, air pressure is generated in the cylinder chamber 2b, and the piston 3 moves to the right in the figure and reaches its stroke end. At this time, the plunger 14 is pushed up by the tapered surface at the tip of the locking ring 9, climbs over it, and then descends to enter the locking groove 9b.

In this state, when the piston rod 4 is pushed to the left in the figure by the load and the air pressure in the cylinder chamber 2b decreases,
When the piston 3 moves to the left by a distance of stroke A, the locking protrusion 9a comes into contact with the plunger 14, and the piston 3
The subsequent movement to the left is restricted, resulting in the state shown in FIG.

Note that the screw portion 14b provided at the upper end of the plunger 14
A stopper nut 14c is screwed into the casing 15, and by rotating the adjustment nut 17 screwed into the casing 15, the plunger 14 can be pulled upward through the middle holder 17 and the nut 14c, and the lock can be released. It looks like this.

FIG. 3 is an enlarged sectional view of the spring device 12.

The spring device 12 includes a housing 2 consisting of a cylindrical portion 22 with a bottom and a connecting portion 23 having a hole 23a connected to a load.
1. A cylindrical member 25 consisting of a mounting portion 26, a flange-like flange 27, and a cylindrical pressing portion 2, a retaining member 24 that prevents the cylindrical member 25 from being removed from the housing 21, and a bush 29. , and a compression spring 30, a screw hole provided in the mounting portion 26 is screwed into a mounting screw 4a at the tip of the piston rod 4, and the cylindrical member 25 and the piston rod 4 are integrally mounted. .

When no load is applied to the connecting portion 23, the compression spring 30
The flange 27 is pressed against the removal prevention member 24,
In this state, there is an appropriate distance between the inner bottom surface 22a of the cylindrical portion 22 and the top surface 28a of the pressing portion 28, and the compression spring 3
When a load is applied in the direction of compressing 0, the housing 21 and the cylindrical member 25 can move relative to each other by a distance of a stroke D equal to this distance. FIG. 3 shows a state where a load is applied, which is an intermediate position of stroke D. However, the load becomes even larger and the inner bottom surface 2
When the top surface 28a and the top surface 28a come into contact, the thrust of the piston 3 is directly applied to the load regardless of the elastic force of the compression spring 30, so that there is no loss in transmission of force from the piston 3 to the load. ing.

According to the embodiment described above, when the air pressure in the cylinder chamber 2b decreases with the piston rod 4 locked by the lock device 11 and a load applied to the spring device 12, the elastic force of the compression spring 30 The connecting portion 23 of the housing 21 presses the load, and even if the load or the piston 3 moves slightly in the axial direction, no backlash occurs and the pressing force can be maintained.

In the above embodiment, if the clamping mechanism of the clamping device is connected to the connecting portion 23 and the workpiece is clamped on the exit side of the piston rod 4 of the cylinder device 1, air is supplied from the bow 7a and the cylinder When air pressure is applied to the chamber 2b, a normal clamping action is performed, and when the pressure of the air pressure source decreases or is disconnected, the locking device 11 causes the piston 3 to move to the left in the axial direction. is regulated, and the clamping force to the workpiece is maintained by the spring device 12.

FIG. 4 is a sectional view showing the main parts of a cylinder device 31 according to another embodiment.

In this cylinder device 31, the piston 32 and the piston rod 36 are not integrally connected, and both can move relative to each other in the axial direction, and there is no compression between the piston 32 and the piston rod 36. A spring 38 is interposed, and the piston rod 36 is biased distally with respect to the piston 32 by the compression spring 38.

That is, the piston rod 36 is inserted into the cavity 3 of the piston 32.
A ring 37 that is slidably fitted into the piston rod 2a and attached to the end of the piston rod 36 prevents the piston rod from being removed. A compression spring 38 is attached.

Further, a locking ring 33 is formed on the piston 32, and the plunger 14 of the locking device 11 is connected to the locking ring 33.
According to this cylinder device 31, the locking device l! enters the locking groove 33b of the piston 32 and restricts the axial movement of the piston 32. ! When the air pressure in the cylinder chamber 2b decreases with the piston 32 locked by 11 and a load applied to the piston rod 36, the tip of the piston rod 36 presses the load due to the elastic force of the compression spring 38. Therefore, the load or piston 3
Even if 2 moves slightly in the axial direction, no looseness occurs and the pressing force can be maintained.

Note that when air is supplied into the cylinder chamber 2b, the piston 32 moves and transmits force to the load via the compression spring 38 and the piston rod 36, but if the load is larger than the elastic force of the compression spring 38. In this case, the top surface 35a of the pressing portion 35 provided on the plug member 34 and the inner bottom surface 36a of the piston rod 36 contact, and the compression spring 38
Regardless of the elastic force of the piston 32, the thrust of the piston 32 is directly applied to the load, so that there is no force transmission loss.

In the above embodiment, the locking device 11 has a structure in which the plunger 14 is moved back and forth in the radial direction of the cylinder to engage with the locking protrusion 9a of the locking ring 9, but these structures are different from each other. Various modifications are possible, and a brake-type locking device that firmly grips the piston rod and locks it by frictional force may be used.

〔Effect of the invention〕

According to the present invention, by locking the piston with the locking device, even when the fluid pressure decreases, the tip of the piston rod presses the load due to the elastic force of the spring member, and the load or the piston moves in the axial direction. Even with slight movement, no backlash occurs and the pressing force can be maintained. Therefore, when a workpiece is clamped by this cylinder device, the clamping force can be maintained even when the fluid pressure decreases.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a partially sectional front view of a cylinder device, FIG. 2 is an enlarged sectional view of a locking device, FIG. 3 is an enlarged sectional view of a spring device, and FIG. 4 is a partially sectional front view of a cylinder device. FIG. 2 is a sectional view showing the main parts of the cylinder device according to the embodiment. l...Cylinder device, 2...Cylinder tube, 3
... Piston, 4... Piston rod, 9... Locking ring, 11... Lock device, 12... Spring device, 30.38... Compression spring (spring member).

Claims (1)

[Claims] In a cylinder device including a cylinder tube, a piston that moves axially within the cylinder tube by fluid pressure, and a piston rod that transmits the axial movement of the piston to a load, the axial movement of the piston can be restricted. A spring member that is elastically deformable in the axial direction is interposed between the piston and the tip of the piston rod, and the tip of the piston rod is held against the piston by the spring member. A cylinder device characterized in that the cylinder is energized toward the tip.