JPH01105004A - Hydraulic cylinder capable of changing position of stoppage - Google Patents

Abstract

PURPOSE:To enable reduction of the driving force of a driving portion by installing a block and a cylinder with their relative motion allowable and also providing a pressure port at a control pressure chamber divided by the block and the cover of the cylinder. CONSTITUTION:When signals are output from a signal generation unit, a driving part 31 and a screw guide 29 are rotated in response to the output and a cylinder 23 moves forward or backward in an axial direction. Even if pressurized air for driving is supplied to pressure chambers 36a or 36b, operating force by this air pressure and operating force by air pressure in a control pressure chamber 26 are nearly equal so that the driving part 31 can move the cylinder 23 by small force. A shifting mechanism 34 adjusts the position of the cylinder 23 and then pressurized air is supplied to/discharged from the supply/discharge ports 37a, 37b to the pressure chambers 36a, 36b so that the piston 24 reciprocates within a predetermined range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluid pressure cylinder in which the stopping position of a piston can be changed by an external signal.

[Prior art] Fluid pressure cylinders are widely used in industrial equipment, but
In response to recent high-volume, low-volume production, the stopping position of the piston of the fluid pressure cylinder is adjusted to an accuracy of ±0.1 to ±0.05 mm each time the production item is changed to match the production process. Settings are frequently reconfigured.

For this reason, there is a strong desire to put into practical use a device that can automatically adjust the stop position of a fluid pressure cylinder accurately and quickly without using human hands.

The inventor of the present invention previously proposed a fluid pressure cylinder that met the above requirements in Japanese Patent Application No. 61-146354 and others.

In the previously proposed fluid pressure cylinder, as shown in FIG. 3, for example, a plot 2 attached to a fixed part 1 and a block 2 are inserted in an airtight sliding position, and the position can be adjusted in the axial direction. The installed cylinder tube 3, the piston 4 that slides inside the cylinder tube, the piston rod 5 that airtightly passes through the rod-side cover 3a that is integrated with or separate from the cylinder tube 3, and the cylinder tube that is activated by an external signal. 3 in the axial direction, and the moving mechanism B is screwed into the screw 8 of the cylinder tube and rotated by the drive of the pulse motor 8 based on an external signal to move the cylinder tube 3. It is composed of a feed lever) 10 that moves forward and backward with respect to the block 2. Reference numeral 11 in FIG. 3 is a protrusion provided on the block side of the cylinder tube 3, and 12 is an origin detector, which detects the origin position of the cylinder tube 3 with high accuracy.

In the fluid pressure cylinder, when a signal is output from a signal generating section (not shown), the pulse motor 9 rotates the nut 10 to be fed by step rotation by a predetermined number of pulses,
As a result, the cylinder tube 3 moves forward and backward relative to the block 2, and when the drive signal stops, the pulse motor 8 and the cylinder tube 3 stop.
By moving back and forth, the stopping position of the piston 4 can be changed with high precision.

However, the previously proposed fluid pressure cylinder lacks consideration for the fluid pressure of the pressure fluid in the pressure chambers 14 and 15 partitioned by the piston 4, so when the cylinder tube 3 is moved leftward in the figure , there is a problem in that a large force is required to move the tube. That is, when pressure fluid is supplied to one of the pressure chambers 14 and 15, this fluid pressure generates a force that pushes the cylinder tube 3 to the right in the figure, so the cylinder tube 3 is pushed to the left against this force. In order to move in this direction, a large driving force is required.

In order to solve this problem, it is possible to discharge the pressure fluid in the pressure chamber 14.15 to the outside when the cylinder tube 3 is moved, but if the pressure fluid in the pressure chamber 14.15 is discharged, the piston 4 will become free. A new problem arises in that the load becomes incapable of holding.

[Problems to be Solved by the Invention] The present invention provides a control pressure chamber between a relatively movable block and a cover of a cylinder, and counteracts the fluid pressures of the pressure chamber and the control pressure chamber. The problem to be solved is to enable relative movement of the block and cylinder with a small force even when fluid pressure is acting on the chamber.

[Means for Solving the Problems] In order to solve the above problems, the fluid pressure cylinder of the present invention includes a cylinder, a piston that slides inside the cylinder, and a piston that airtightly penetrates one cover of the cylinder. a rod, and a block axis that airtightly passes through the block and the other cover of the cylinder, which are relatively slidable within the cylinder;
The cylinder and block are driven by a control pressure chamber defined by the block and the other cover, a pressure port for supplying pressure fluid to the control pressure chamber, and a drive section based on an external signal. The present invention is characterized in that it includes a movement mechanism that relatively moves the piston in the sliding direction.

[Function] When pressure fluid is supplied from the pressure port to the control pressure chamber, the acting force due to the fluid pressure in the control pressure chamber and the acting force due to the fluid pressure in the pressure chamber act against the cylinder, so pressure is applied to the pressure chamber. Even when fluid is supplied, the block and cylinder can be moved relative to each other with a small force to maintain the piston's stopping position.
The location can be changed.

[Embodiment] Fig. 1 shows a first embodiment of the present invention in which a cylinder is movable with respect to a block, and the fixed part 21 to which the block 22 is attached is usually constituted by a part of the equipment to which the pneumatic cylinder is attached. Kudzu.

The block 22 is inserted airtightly and slidably into a cylinder tube 23a of a cylinder 23 whose position can be adjusted in the axial direction by a moving mechanism to be described later. The piston rod 25 of the piston 24, which hermetically passes through the cover 23b and slides inside the cylinder tube 23a, hermetically passes through the rod side force', <-23c, and is formed between the block 22 and the cover 23b. A pressure port 27 for supplying pressurized air for control is opened in the control pressure chamber 2B.

A threaded rod 29 and a guide rod 30 are installed in parallel with the cylinder 23, and one end of the threaded rod 2θ is connected to a drive unit 31 such as a servo motor or a pulse motor attached to the fixed part 21 by a joint. The other end of the guide rod 30 is pivotally supported by a bracket 32, and one end of the guide rod 30 is fixed to the fixed portion 21.

Further, the feeding plate 33 whose intermediate portion is fixed to the cylinder tube 23a has a female thread on the negative side screwed into the threaded rod 28, and a through hole on the other side loosely fitted into the guide rod 3o, so that the threaded rod 28 and The feed plate 33 constitutes a moving mechanism 34 for the cylinder 23 .

Therefore, when the threaded rod 28 rotates due to the rotation of the drive unit 31, the feed plate 33 and the cylinder 23 integrated therewith advance and retreat in the axial direction of the block 22, thereby setting the block side stopping position of the piston 24. Ru.

Note that, if necessary, a control brake can be installed on the shaft of the drive section 31 to prevent the stop position of the cylinder 23 from shifting due to a collision of the piston or a load.

Although not shown in the drawings, a protrusion for setting the moving position of the cylinder 23 is provided on the cylinder 23 or the feed plate 33, and this protrusion is attached to the fixed part 21 to generate an electric signal at the origin of the moving position of the cylinder 23. It is possible to provide an origin position detector consisting of a switch or the like to generate the .

Supply/discharge ports 37a, 37b for supplying and discharging pressurized air to and from pressure chambers 38a, 38b partitioned by pistons are provided in the block 22, block shaft 22a, and cover 23b.

The fluid pressure cylinder includes a block 22 and a cover 23c.
In addition to the pressure air supply/discharge port, there are no members that require a relatively large amount of space, such as a member that determines the stopping position of the piston, so the block 22 and cover 23c are
A damping mechanism can be provided to dampen the piston.

Next, the operation of the first embodiment will be explained.

When moving the cylinder 23, pressurized air is supplied from the pressure port 27 to the control pressure chamber 2G in advance.

When a signal is output from a signal generating section (not shown), the drive section 31 and screw rod 29 rotate according to the output, which causes the moving mechanism 34 to move the cylinder 23 forward and backward in the axial direction, and the signal stops. The cylinder 23 stops.

In this case, even if the pressure air for driving is supplied to the pressure chamber 36a or 36b, the acting force due to this air pressure and the acting force due to the air pressure in the control pressure chamber 26 act approximately equally and in opposition, so that the cylinder Since almost no force in the axial direction due to fluid pressure acts on the cylinder 23, the drive unit 31 can move the cylinder 23 relative to the block 22 with a small force. The applied force can be reduced. Further, the air pressure supplied to the control pressure chamber 26 may be the same as the drive air pressure, or may be an air pressure that is appropriately pressurized or reduced.

After adjusting the position of the cylinder 23 by the moving mechanism 34, the pressure chambers 36a, 3Gb are opened from the supply and discharge ports 37a, 37b.
By supplying and discharging pressurized air to and from the piston 24, the piston 24 reciprocates within a predetermined range C.

FIG. 2 shows a second embodiment of the invention in which a block 42 is movable relative to a pneumatic cylinder attached to the fixed part 21, the cylinder 43 being fixed by a cover 43b closing the block side of the cylinder tube 43a. The piston rod 25 of the piston 24, which is attached to the cylinder tube 43a and slides inside the cylinder tube 43a, hermetically passes through the rod-side cover 43c and is inserted into the cylinder tube 43a in an airtight and slidable manner. The block shaft 42a of 42 passes through the force <-43b airtightly, and a port 27 for supplying pressure air for control is opened in the control pressure chamber 26 formed between the block 42 and the cover 43. ing.

The block shaft 42a has a feed plate 45 having the same structure as the feed plate 33 of the first embodiment fixed to the tip that passes through the cylinder 43, and a screw threaded into the feed plate 45 and its threaded portion. The rod 28 constitutes a moving mechanism 4B.

Since the other configurations of the second embodiment are the same as those of the first embodiment, the same reference numerals are given in the drawings and detailed explanations are omitted.

Second. i! The function of the embodiment is that the drive unit 31 and the transfer mechanism 4B
The second embodiment is the same as the first embodiment except that the block 42 moves forward and backward relative to the cylinder 43 in the sliding direction of the piston 24, so a detailed explanation will be omitted.

Although not shown in the drawings, a driving section and a moving mechanism may be separately provided for the cylinder and the block to relatively move them.

Furthermore, the moving mechanisms 34 and 48 can have a similar configuration to the previously proposed moving mechanism shown in FIG. 883.

[Effects of the Invention] The present invention provides a block and a cylinder that are movable relative to each other, and a pressure port that supplies pressure fluid to a control pressure chamber that is partitioned by a block and a cover of the cylinder. Even if the driving fluid is supplied to the pressure chamber of Although the piston holds the load using fluid pressure, the driving force of the driving unit that moves the cylinder and the block relative to each other can be reduced.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the schematic structure of first and second embodiments of the present invention, and FIG. 3 is a cross-sectional view showing the schematic structure of a previously proposed fluid pressure cylinder. 22.42 ・@Block, 22a, 42a ・Block shaft, 23.43 Φ ・Cylinder, 23b, 23c, 43b, 43cm m cover 1.2
4. Piston, 25. Piston rod, 28.e
Control pressure chamber, 27...pressure port. 31...Drive unit, 34.48...Movement mechanism. Figure 3!

Claims (1)

[Claims] 1. A cylinder, a piston that slides within the cylinder, a piston rod that passes through one cover of the cylinder in an airtight manner, a block that is relatively slidable within the cylinder, and a block that passes through the other cover of the cylinder in an airtight manner. axis and
The cylinder and block are driven by a control pressure chamber defined by the block and the other cover, a pressure port for supplying pressure fluid to the control pressure chamber, and a drive section based on an external signal. A fluid pressure cylinder whose stop position can be changed, characterized by comprising a movement mechanism for relatively moving a piston in a sliding direction.