JPS5912882B2 - Pneumatic sizing cylinder device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sizing cylinder device capable of imparting any amount of linear motion to a load.

Fluid pressure cylinders such as hydraulic cylinders and pneumatic cylinders are often used as feeding devices for machine tool tables and other moving objects. In this case, it is necessary to detect the position of the table and feed back the detected value to the fluid pressure cylinder.
Magnetic scales, limit switches, and dogs must be installed along the movement path of the table or moving object, and therefore, the structure of the machine body such as a machine tool is complicated in machines that use fluid pressure cylinders as feeding devices. It had the disadvantage of becoming

Therefore, in recent years, so-called fixed-size cylinders have been developed that can apply an arbitrary amount of feed motion to a moving object such as a table without providing any detection means in the main body of the machine tool by providing a feedback loop in the fluid pressure cylinder itself. Equipment is commercially available.

This known sizing cylinder device only has hydraulic cylinders,
Or, most of them share a pneumatic cylinder and a hydraulic cylinder, and almost none use only a pneumatic cylinder.

The reason for this is that when the working fluid is a compressible fluid, positioning accuracy becomes extremely low.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sizing cylinder device that is highly accurate despite being of the air king type.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. Prior to this, an example of a conventional pneumatic sizing cylinder device that is commercially available will be described with reference to FIG. 1.

FIG. 1 shows an example of a conventionally known pneumatic sizing cylinder device. In the figure, 1 is a main cylinder, and ports 1a at both ends of the main cylinder 1.

An air pressure source 3 is connected to 1b via a center supply type 4-way, 3-position valve 2.

On the other hand, a sub-cylinder 4 is provided in parallel with the main cylinder 1, and two-position switching valves 5 and 6 are connected to ports 4a and 4b at both ends of the sub-cylinder 4, one of which is a two-position switching valve. A bypass passage 8 in which a variable throttle valve 7 is installed is provided parallel to the valve 5 .

The main piston 9 inserted into the main cylinder 1 and the auxiliary piston 10 inserted into the auxiliary cylinder 4 are mechanically integrated via their respective piston rods 1L12 and connecting rods 13. .

The sub-cylinder 4 is filled with pressure oil 14, and this pressure oil 14
is confined in a closed pipeline including switching valves 5 and 6,
It will not be discharged into the tank.

In the conventional pneumatic sizing cylinder device shown in FIG.
Since the working fluid that drives the main piston 9 is compressible air, the use of the hydraulic sub-cylinder 4 prevents the stopping accuracy from becoming extremely poor when using the main cylinder 1 alone.

According to this conventional device, positioning can be performed with fairly high precision, but in order to drive the main piston 9, the sub piston 10 in the sub cylinder 4 must also be driven at the same time. However, the main cylinder 1 and the air pressure source 3 connected thereto had to be made larger than necessary.

Also, since there is resistance due to hydraulic pressure when starting,
Some large fish were unable to move the piston rod, that is, the load, at high speeds and were unable to perform quick positioning operations.

The present invention has been made in view of the drawbacks of the conventional pneumatic sizing cylinder device, and has high positioning accuracy.
To provide a compact, high-performance pneumatic sizing cylinder device that can be operated at high speed and driven by a relatively small pneumatic source.

The configuration of the first embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

As shown in FIG. 2, the pneumatic sizing cylinder device according to the present invention includes a main cylinder 15 of a pneumatic drive mechanism and a sub cylinder 16 aligned with the main cylinder 15.
The main part of the gripping mechanism and the main part of the hydraulic braking mechanism, the detailed structure of which will be explained later, are accommodated in the sub-cylinder 16.

Main piston 17 housed in main cylinder 15
A piston rod 18 that penetrates through the sub-cylinder 16 and protrudes to the outside is fixed to the main cylinder 15, and the main cylinder 15 is connected to a center supply type 4-way 3-position valve 19A through ports 15a and 15b at both ends thereof. The pneumatic drive control device 19 includes a pneumatic source 19B.

A first chamber 20 is formed in the sub-cylinder 16 adjacent to the end plate of the main cylinder 15, and within this first chamber 20 is an annular grip that slides relative to the piston rod 18. A secondary piston 21 of the mechanism is housed therein.

As clearly shown in FIGS. 2 and 4, one end of the secondary piston 21 is provided with a conical hole 21a and a left protrusion 21A.
The protruding portion 21A is inserted into a second chamber 22 having a small diameter and communicating with the first chamber.

A collet 23, which is a gripping member for a gripping mechanism and a deceleration braking mechanism, is housed in the second chamber 22, and has conical diameter reduction portions 23A and 23B at both ends. - It is inserted into the hole 21a of the secondary piston 21 and connected to the second secondary piston 21 by a pin 24.

A pin 24 connecting the two is provided to protrude from the inner surface of a conical hole 21a of the first sub-piston 21, and a hole 23a of the collet 23 into which this pin 24 is received has an inner diameter larger than the diameter of the pin 24. ing.

Therefore, both can move relative to each other in the axial direction of the piston rod, albeit slightly.

The collet 23 is movable relative to the piston rod 18 and consists of several arcuate members 26 connected to each other via springs 25, as shown in FIG.

A spring 25 connecting each arc-shaped member is connected to each arc-shaped member 2.
6 are pushed away from each other, so the collet 23 is always given an expansion force and the piston rod 18
It is loosely fitted to the

Inside the sub-cylinder 16, a third chamber 27 which communicates with the second chamber 22 is provided adjacent to the second chamber 22, and a fourth chamber 28 is formed adjacent to the third chamber 27. has been done.

The third chamber 27 has a larger inner diameter than the second chamber 22 and the fourth chamber 28, and the third chamber 27 has a protrusion that is inserted into the second chamber 22 and the fourth chamber 28. A second sub-piston 29 of the deceleration braking mechanism having 29A and 29B is accommodated.

As shown in the figure, the second sub-piston 29 is loosely fitted to the piston rod 18 and can move relative to the piston rod 18.

A conical hole 29a that engages with the outer peripheral surface of the other end 23B of the collet 23 is formed in the protrusion 29A inserted into the second chamber 22 of the second sub-piston 29, and
The protrusion 29B inserted into the fourth chamber 28 has a cylindrical shape, and the coil spring 30 accommodated in the fourth chamber 28 is inserted into the hole.
Half of it is loaded.

The coil spring 3 inserted into the fourth chamber 28
0 always urges the second sub-piston 29 to the right in FIGS. 2 and 4.

A pneumatic operating device 31 consisting of a four-way two-position valve 31A and a pneumatic pressure source 31B is connected to both ends of the first chamber 20 formed in the sub-cylinder 16 via ports 20a and 20b.
The pneumatic operating device 31, the second ILJ histone 21, and the collet 23 constitute a gripping mechanism for gripping the piston rod 18.

On the other hand, ports 27a are provided at both ends of the third chamber 27.

A deceleration control device 32, which is a hydraulic circuit including a switching valve 32A, a variable throttle valve 32B, and a reversal valve 32C, is connected to the deceleration control device 32, the second sub-piston 29, and the spring 30 through 27b and the pipe line. What is piston rod 1
8 constitutes a braking mechanism for reducing braking.

The deceleration control device 32 included in this deceleration braking mechanism does not include any pressure oil source such as a pump, and the pressure oil is sealed in a closed pipe line including the third chamber 27.

Next, the operation will be explained with reference to FIGS. 2, 5, and 6.

First, when starting, as shown in FIG.
Switch A to supply compressed air from the air pressure source 19B to the main cylinder.
At the same time, the four-way, two-position valve 31A in the pneumatic operating device 31 is set to the state shown in FIG. 2, and compressed air is fed into the left side of the chamber 20 from the pneumatic source 31B.

Then, by opening the switching valve 32A in the deceleration control device 32, the chambers 27 on both sides of the second sub-piston 290 are communicated via the variable throttle valve 32B and the reversal valve 32C.

At this time, since neither the secondary piston 21 nor the collet 23 is engaged with the piston rod 18, the main piston 17 rapidly moves to the left in FIG.

A signal is generated from a main control device (not shown) before the scheduled stop position (the movement of the piston rod 18 is constantly detected by a detector that follows the piston rod 18).

), the valve 31A in the pneumatic operating device 31 is switched to the position shown in FIG. 5, and compressed air is fed into the right side of the chamber 20.

Therefore, the secondary piston 21 moves to the left, and then the collet 23 also moves to the left and contracts at the same time to grip the piston rod 18.

However, at this time, the first sub-piston 21 is still moving leftward, so the piston rod 18 is not braked.

Next, the tip 23B of the collet 23 is connected to the second sub-piston 29.
As a result, the first sub-piston 21, the collet 23, and the second sub-piston 29 become integrated, and these together with the piston rod 18 become integrated.

Therefore, the driving force to the main piston 17 and the driving force to the second sub-piston 21 are applied to the second sub-piston 29 via the collet 23.

For this reason, the second sub-piston 29 tries to move to the left in the chamber 27 in which it is housed, as shown in FIG. This is gradually reduced by the resistance force of royal oil passing through 32B, and the piston rod 18 is gradually braked at a predetermined deceleration rate.

When the piston rod 18 that has been decelerated in this way reaches a predetermined stopping point, the valve 19A in the mustard drive control device 19 and the deceleration control device 32 are activated by a command from a control device (not shown) in the same manner as described above. The valve 32A is switched to the state shown in FIG. The chambers 27 on both sides are cut off from communicating with each other and the pressure oil therein is sealed.

Therefore, both the main piston 17 and the second sub-piston 29 are restrained, and the piston rod 18 is completely stopped.

At this time, in order to maintain the restraint of the piston rod 18 by the collet 23, air pressure is applied to the right side of the secondary piston 21 in the same manner as during the deceleration operation.

Next, the operation of releasing the piston rod from the stopped state shown in FIG. 6 and returning the main piston 17 to its original position will be described.

When a return command is given to a control device (not shown), the signal from the control device first moves the valve 31A in the pneumatic operating device 31 to the right in FIG. 6, and then moves the valve 32A in the deceleration control device 32 to the right. is also moved downwards and finally valve 19A in device 19 is moved to the right in FIG.

As a result, in the chamber 27, the pressure oil on the right side of the piston 29 can flow to the left side of the piston 29 through the check valve 32C with almost no resistance.
Compressed air is introduced to the left side of the piston 21, and compressed air to the right side of the piston 21 can be discharged.

As a result, the main piston 17 moves to the right in FIG.
is moved to the right by compressed air from the pneumatic source 31B in the device 31, so that the main piston 17 is rapidly moved to the right.

In this process, the engagement between the second sub-piston 29 and the collet 23 is released, and the collet 23 is moved to the second sub-piston 21.
It will be pulled back to its original position.

On the other hand, after the main piston 17 is driven to the right stroke end, it is stopped by switching the valve 19A.

In the first embodiment shown up to FIG. 6, the main piston 1
No braking is applied in the return direction of cylinder 1, but if a double action type device is constructed, a symmetrical secondary cylinder may be provided on the right side of the main cylinder.

The mechanism for gripping the piston rod does not necessarily need to use a collet; other mechanisms could perform the same function.

FIG. 7 shows a second embodiment of the present invention, and shows a mechanism that can decelerate the piston rod before a predetermined position and then stop it when the piston rod 8 is driven in any direction.

(In FIG. 7, the parts indicated by the same reference numerals as in FIG. 2 are the same as the parts shown in FIG. 2, so the explanation of these parts will be omitted.

) In FIG. 7, the piston rod 18 connected to the main piston in the main cylinder 15 passes through the sub cylinder 16 and projects outward, and is connected to an arbitrary load (for example, a table of a machine tool). Ru.

A first chamber 3 in which a pair of pistons 33A and 33B loosely fitted into a piston rod 18 is accommodated in the sub-cylinder 16.
4 is provided, and this chamber 34 is connected to a pneumatic operating device 35 at a port 34a located between the pistons 33A and 33B.

The pneumatic operating device 35 includes a pneumatic source 35A and a two-way, two-position valve 35.
B, and can exhaust the inside of the chamber 34 or introduce high pressure air into the chamber 34.

The pistons 33A, 33B are arranged opposite to each other in the chamber 34, and have steel balls 36A, 36 arranged on their respective back surfaces.
Hydraulic pistons 37A, 37 behind each via B
It is possible to engage and disengage from B.

Hydraulic pistons 37A and 37B are located in chambers 38A and 38, respectively.
It can move within B and has holes 37a and 37b whose diameter decreases in the direction adjacent to the pistons 33A and 33B.

Room 38A. 38B are ports a, b, c at each end
, d are filled with pressure oil by hydraulic circuits 39A and 39B connected to the circuits 39A and 39B.

The hydraulic circuits 39A and 39B are composed of a switching valve S, a variable throttle valve T, and a check valve C, and the pressure oil in the chambers 38A and 38B is supplied to the hydraulic circuit 39A.

It is sealed via 39B.

Coil springs 40 are installed between the pistons 33A, 33B and the hydraulic pistons 37A, 37B behind them.
A, 40B are arranged, and this coil spring 40A,
40B urges the piston 33A and the hydraulic piston 37A, and the piston 33B and the hydraulic piston 37B, respectively, in a direction to move away from each other.

Therefore, when the device 35 is not actuated, the pistons 33A, 3
Piston 33A is integrated with hydraulic piston 37A via steel balls 36A and 36B at the rear end of piston 3B, and piston 33B is integrated with hydraulic piston 37B.

In operation, first, the switching valve 35B is moved downward in FIG. 7 using the pneumatic operating device 35 to send high pressure air into the chamber 34 from the pneumatic source 35A.

At this time, the hydraulic circuits 39A and 39B are maintained in the state shown in FIG.

Then, the pistons 33A and 33B are driven away from each other by the high pressure air sent into the chamber 34, and as a result, the piston 33A and the oil field piston 37A are disengaged, and the piston 33B and the hydraulic piston 37B are
is disengaged.

After this condition is reached, if high pressure air is introduced to the right side of the main piston (not shown) in the main cylinder 15,
Since there is no resistance acting on the piston rod 18, the piston rod 18 moves rapidly to the left.

When the load connected to the piston rod 18 approaches a predetermined stopping point, the switching valve 35B in the pneumatic operating device 35 is switched by a command from a control device (not shown).
5B is returned to the state shown in FIG. 7 again.

Then, the inside of the chamber 34 is exhausted, so the piston 33A.

33B are moved away from the hydraulic pistons 37A, 37B by the force of the springs 40A, 40B, respectively, and as a result, the steel ball 36A.

Piston 33A and hydraulic piston 37A via 36B,
The piston 33B and the hydraulic piston 37B are respectively connected and fixed on the piston rod 18.

Therefore, the piston 33A and the hydraulic piston 37A, and the piston 33B and the hydraulic piston 37B move to the left in FIG. 7 together with the piston rod 18.

In this case, in the chamber 38B in which the right hydraulic piston 37B is accommodated, as the hydraulic piston 37B moves to the left, pressure oil is pushed out through the port c and through the throttle valve T in the hydraulic circuit 39B. Therefore, the hydraulic piston 37B is decelerated in response to the opening of the throttle valve T, but no load is applied to the left hydraulic piston 37A.

(The reason is that in the chamber 36A housing the left hydraulic piston 37A, the hydraulic circuit 3 is connected from the left port a to the chamber 36A.
This is because the pressure oil pushed out by the valve 9A passes through the check valve C without passing through the throttle valve T, so the hydraulic piston 37A does not receive any resistance.

) Therefore, the piston rod 18 is decelerated to the speed prescribed by the throttle valve C via the hydraulic piston 37B.

Then, at the stopping point, the air pressures acting on both sides of the main piston are equalized, and at the same time, the switching valve S in the hydraulic circuit 39B is switched downward from the state shown in FIG. The pressure oils are isolated from each other, thus
Braking is applied to both the main piston and hydraulic piston 37B.

On the other hand, when driving the piston rod 18 to the right in FIG. 7, by operating the left hydraulic circuit 39A in the same manner as described above, the piston rod 18 is
8 can be decelerated and then stopped.

(This operation is the same as above, so the explanation will be omitted.

FIG. 8 shows another embodiment of the deceleration control device 32 in the first embodiment shown in FIG. A variable throttle valve 50C and a check valve 50D are connected.

This device 50 is connected to the port 27b in FIG.
7a, and is operated as follows in order to apply deceleration and braking to the piston rod 18 in the device shown in FIG.

That is, the switching valve 50A is switched from the state shown in FIG. 8 to open the switching valve 50A.

Then, the pressure oil flows into the device 50 through the port 27b following the left side of the second sub-piston 29, and the flow rate determined by the throttle valve 50C flows back into the chamber 27 through the port 27a.

When stopped, the switching valve 50A is activated by a command from the main controller.
is again switched to the state shown in FIG. 8, and the pressure oil in the chamber 27 is sealed.

Therefore, the pressure oil on both sides of the second sub-piston 29 is equal and does not flow, so the second sub-piston 29 is reliably stationary.

On the other hand, the switching valve 50B is used for decelerating and stopping the main piston 17 when it is moved to the right in FIG. 2, and in this case, one more sub-cylinder 16 may be provided.

As explained above, according to the present invention, the piston rod that has been rapidly moved to the vicinity of a predetermined position is first held in place by the gripping mechanism, and the braking is applied after the gripping mechanism is decelerated. In addition, since the piston rod is mechanically gripped and decelerated by hydraulic pressure resistance, the device becomes smaller.
Moreover, accurate positioning is now possible.

Further, since the device of the present invention is operated only by air pressure, it can be used even in places where explosion resistance is required.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventionally known pneumatic sizing cylinder device;
Fig. 2 is a schematic diagram of the pneumatic sizing cylinder device according to the present invention, and is a diagram explaining the state at the time of starting, and Fig. 3 is a diagram showing the -
■A sectional view taken in the direction of arrows, Figure 4 is a partially enlarged view of the device shown in Figure 2, Figures 5 and 6 are explanatory diagrams of the operation of the device shown in Figure 2, and Figure 7 is a book Figures showing other embodiments of the invention; FIG. 8 is a diagram showing a partially modified embodiment of the apparatus shown in FIG. 2;
It is. 15...Main cylinder, 16...Sub-cylinder, 1
7...Main piston.

Claims (1)

[Claims] 1. A main cylinder, a main piston that reciprocates in the axial direction within the main cylinder, and a piston that is fixed to one end of the main piston and protrudes outward through one end of the main cylinder. a pneumatic drive mechanism consisting of a rod and a pneumatic drive device that sends compressed air into the main cylinder to drive the main piston; a gripping member provided around the piston rod protruding from the main cylinder; , a secondary piston that moves in the axial direction of the piston rod and applies a holding force to the gripping member, and a secondary piston that is provided adjacent to the main cylinder that houses the secondary piston and the gripping member. a gripping mechanism comprising a cylinder and a pneumatic operating device that sends compressed air into the secondary cylinder to drive the secondary piston; a second sub-piston provided therein, a braking gripping member that receives a driving force from the second sub-piston and grips the piston rod, and urges the second sub-piston in the direction of holding the piston rod. a deceleration braking mechanism comprising a coil spring and a hydraulic circuit communicating oil-filled spaces on both end surfaces of the second sub-piston; driving the piston via the pneumatic drive device; A pneumatic sizing cylinder device comprising: a control mechanism that detects movement of a rod and controls the pneumatic operating device and the hydraulic circuit to grip, decelerate and stop the piston rod. 2. The pneumatic sizing cylinder device according to claim 1, wherein the braking gripping member of the deceleration braking mechanism is shared with the gripping member of the gripping mechanism.