JPH0245524Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a synchronous cylinder drive device capable of synchronously driving a constant speed traveling body.

[Conventional technology]

Conventionally, there has been an idea to use a pneumatic cylinder as a synchronous interlocking device with a traveling body such as a conveyor that travels at a constant speed. For example, as shown in Figure 5,
A workpiece 51 on a belt conveyor 50 running at a constant speed
The work 51 is clamped by the clamp cylinder 54 attached to the rod 53 while the rod 53 of the synchronous cylinder 52 is driven synchronously. The necessary machining is performed on the workpiece 51 using a tool, and after the machining is completed, the clamp of the clamp cylinder 54 is released, and the rod 53 is reversed and returned to its stroke before it reaches the end of the drive stroke.
The purpose is to return it to its original position.

The synchronous cylinder 52 is connected to a pressure reducing valve 5 in a flow path that communicates the high-pressure air source 1 shown in the figure with the cylinder's drive side pressure chamber 55 and return side pressure chamber 56, respectively.
When the cylinder is driven by a well-known cylinder drive device equipped with 7, 57 and a supply/discharge switching valve 58, the cylinder drive speed changes depending on the level of the set pressure of the pressure reducing valve. However, since it is extremely difficult to finely adjust the set pressure of the pressure reducing valve so as to obtain a speed synchronized with the belt conveyor 50 traveling at a constant speed, this well-known cylinder drive device is used as the drive device for the synchronous cylinder 52. is inappropriate.

Note that even if the air pressure of the high-pressure air source 1 is set in advance to the pressure used for driving and returning the piston and the pressure reducing valves 57, 57 are omitted, it is extremely difficult to finely adjust the set pressure of the high-pressure air source 1. The same is true for pressure reducing valves.

As mentioned above, when the driving speed of the cylinder changes depending on the level of air pressure, a restriction is provided between the pressure reducing valve 57 and the supply/discharge switching valve 58 in the flow path of the drive side pressure chamber 55, thereby It is conceivable to drive with meter-in control. In this way, fluctuations in the air flow rate due to adjustment of the set pressure of the pressure reducing valve 57 etc. can be reduced, so even if it is difficult to finely adjust the set pressure of the pressure reducing valve 57, the belt can run at a constant speed in the cylinder. It becomes easy to drive in synchronization with the conveyor 50.

However, in the synchronous cylinder 52, when the rod 53 starts to move together with the workpiece 51, since the rod 53 is equipped with heavy objects such as the clamp cylinder 54 and processing tools, the start-up is slow, and the rod 53 starts to move together with the workpiece 51. In addition to the difficulty of controlling the behavior, such as stroking under tension, when driven with meter-in control, there is an additional difficulty in the start-up due to the throttle, which makes it difficult to control the movement from start-up to constant speed running. This is not preferable because it takes a long time. Therefore, at present, a satisfactory synchronous drive device has not been obtained.

In addition, after processing the workpiece 51, the next workpiece 51
In order to prepare for machining, perform a return stroke as soon as possible before reaching the end of the drive stroke,
Moreover, it is necessary to return it to its original position in a buffering manner.

[Problem that the invention attempts to solve]

The present invention enables good uniform motion by driving the cylinder with meter-in control, and provides a good start-up by assisting the start-up with a tank that has stored pressure in advance, and also during the return stroke. In this method, a high-pressure air source is directly communicated with the return side pressure chamber to perform the return stroke as quickly as possible, and the exhaust from the drive side pressure chamber is controlled to increase the pressure in the drive side pressure chamber, thereby reducing the return stroke speed. Although the cylinder is decelerated near the end of the stroke, the relief valve prevents rebound and excessive deceleration due to excessive pressure rise in the drive side pressure chamber, thereby synchronizing the cylinder drive with the constant speed traveling body. The problem to be solved is to return the motor to its original position quickly and in a buffered manner to prepare for the next drive.

[Means for solving problems]

The synchronous cylinder drive device of the present invention, which can be driven synchronously with a constant-speed traveling body, has a flow path that communicates a high-pressure air source with a drive-side pressure chamber and a return-side pressure chamber of the cylinder, and alternately connects both chambers with high-pressure air. A supply/discharge switching valve is provided for switching communication between the air source and the atmosphere, and between the high pressure air source and the supply/discharge switching valve in the flow path between the high pressure air source and the drive side pressure chamber, from the high pressure air source side, A variable throttle that meters-in controls the drive stroke of the cylinder and a pressure storage tank that assists in starting the drive stroke are sequentially connected, and a control that controls the return stroke speed is provided between the supply/discharge switching valve of the flow path and the drive side pressure chamber. The control valve is connected in parallel with a check valve that prevents high-pressure air from flowing out from the drive side pressure chamber, a throttle that restricts the flow, and a relief valve that operates near the end of the return stroke. The above problems were solved.

[Effect]

When the supply/discharge switching valve is switched to a position where the high-pressure air source is communicated with the drive-side pressure chamber and the return-side pressure chamber is communicated with the atmosphere, the high-pressure air in the pressure accumulation tank located closer to the supply/discharge switching valve than the variable throttle is released. Flows into the drive side pressure chamber, so the piston is activated against the static inertia force, and is then driven by meter-in control by the high pressure air flowing through the variable throttle and the check valve of the control valve.

In this case, since the amount of air flowing into the drive-side pressure chamber is kept constant, the piston is driven at a constant speed unless there is a load change, so the cylinder can be driven in synchronization with the constant speed traveling body.

Near the end of the piston's drive stroke, the supply/exhaust switching valve is switched to allow air from the high-pressure air source to communicate with the return-side pressure chamber and also communicate the drive-side pressure chamber with the atmosphere. The piston then quickly reverses to its return stroke. On the other hand, the exhaust from the drive side pressure chamber is
Since its outflow is restricted by the throttle of the control valve, back pressure is generated in the drive side pressure chamber, and this back pressure decelerates the piston near the end of its return stroke. When the back pressure in the drive-side pressure chamber rises above the set pressure, the relief valve operates to release the exhaust gas from the drive-side pressure chamber to the atmosphere, thereby preventing bouncing of the piston and excessive deceleration. When the pressure in the drive side pressure chamber drops below the set pressure due to the operation of the relief valve,
The relief valve closes again and the piston returns to its original position in a cushioning manner due to the exhaust through the throttle.

Also, during the return stroke described above, air from the high pressure air source flows through the restriction into the accumulator tank in preparation for the next activation of the cylinder.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In FIG. 1, 1 is a high-pressure air source;
Reference numeral 2 denotes a cylinder driven by the cylinder 2, and inside the cylinder 2, a driving side pressure chamber (rod chamber) 5 and a return side pressure chamber (head chamber) 6 are defined by a piston 3 equipped with a rod 4. By supplying high pressure air to the drive side pressure chamber 5 or the return side pressure chamber 6, the rod 4 is configured to make a drive stroke in the direction of the arrow or a return stroke in the direction of extension.

The high-pressure air source 1, drive side pressure chamber 5, and return side pressure chamber 6 are communicated through a rod side flow path 7 and a head side flow path 8 that are parallel to each other, and air is supplied and discharged midway through these flow paths 7 and 8. The switching valve 9 is connected, and by switching the supply/discharge switching valve 9, one flow path is maintained in communication state, and the other high-pressure air source side flow path is blocked, and the flow path is connected to the blocked flow path. The drive side pressure chamber 5 or the return side pressure chamber 6 is configured to be open to the atmosphere. Therefore, between the high pressure air source 1 and the supply/discharge switching valve 9 in the rod side flow path 7,
Pressure reducing valve 1 that sets the supply pressure to the drive side pressure chamber 5
0, a variable throttle 11 for meter-in control that sets the flow rate to the drive side pressure chamber 5 and constants the drive stroke speed, and a tank 12 for pressure accumulation are connected, respectively, and the supply/discharge switching valve 9 and the drive side pressure chamber An integrated control valve 13 for controlling the return stroke of the cylinder is connected between the cylinder and the cylinder. Above control valve 1
3 has a structure in which a small-opening variable throttle 14, a relief valve 15, and a check valve 16 are connected in parallel, and in the return stroke, the flow of high-pressure air from the drive side pressure chamber 5 is controlled by the throttle 14. When the pressure in the drive-side pressure chamber 5 has risen to the desired high pressure, the high-pressure air is released to the relief valve 1.
Further, the check valve 16 is configured to prevent high-pressure air from flowing out from the drive-side pressure chamber 5 and to allow it to flow into the drive-side pressure chamber 5. . In addition, the high pressure air source 1 in the head side flow path 8
A pressure reducing valve 17 that sets the supply pressure to the return side pressure chamber 6 is connected between the supply and discharge switching valve 9 . In addition, the reference numeral 18 in FIG. 1 is a clamp cylinder fixed to a rod, and 19a is a conveyor 1 that runs at a constant speed.
This is the work (load) above 9.

Next, the operation of the cylinder drive device having the above configuration will be explained.

First, in order to drive the piston 3, rod 4, and load 18 in the cylinder 2 in the direction of the arrow, the supply/discharge switching valve 9 is energized to switch it from the illustrated switching position to another position. This results in
The high pressure air source 1 is a pressure reducing valve 10, a variable throttle 11, a supply/discharge switching valve 9, and a check valve 16 in a control valve 13.
At the same time, the tank 12 communicates with the drive side pressure chamber 5 via the supply/discharge switching valve 9 and the check valve 16, and the return side pressure chamber 6 communicates with the supply/discharge switching valve 9. through which it communicates with the atmosphere. Through this communication, first, the high pressure air stored in the tank 12 flows into the drive side pressure chamber 5, and the piston 3 etc. are started up well against the static inertia force and run at a constant speed in a short time. After that, the high pressure air from the high pressure air source 1 is reduced in pressure by the pressure reducing valve 10 and the variable throttle 1
1, the piston 3 flows into the drive side pressure chamber 5 while its flow rate is controlled by 1, and if there is no change in load, the piston 3 and the like maintain the above-mentioned constant speed movement and are stroked at a good constant speed drive by so-called meter-in control. Along with this drive stroke, the high pressure air in the return side pressure chamber 6 is discharged to the atmosphere via the supply/discharge switching valve 9.

After the drive stroke, in order to return the piston 3 etc. to the original position shown in the figure, the supply and discharge switching valve 9 is de-energized before the piston 3 etc. reach the end of the drive stroke. 9 to the position shown. By this switching, the high pressure air source side of the rod side flow path 7 is shut off, the drive side pressure chamber 5 is communicated with the atmosphere via the control valve 13 and the supply/discharge switching valve 9, and the high pressure air source 1 is connected to the pressure reducing valve. 1
7 and a supply/discharge switching valve 9 to communicate with the return side pressure chamber 6. Therefore, the supply of high pressure air from the high pressure air source 1 to the drive side pressure chamber 5 is stopped, and at the same time, the high pressure air from the high pressure air source 1 is supplied to the return side pressure chamber 6 via the pressure reducing valve 17. , a biasing force is applied to the piston 3 in the return direction by the high-pressure air, and this acting force overcomes the kinetic inertia of the piston 3, etc., and after stopping the piston 3, etc., it moves in the opposite direction from before. Make a return stroke. Then,
Since the head side flow path 8 is not provided with a restriction for controlling the flow rate, the return stroke is performed at a higher speed than the previous drive stroke. Along with the return stroke, the high pressure air in the drive side pressure chamber 5 is released to the atmosphere, but in the middle of this, a small aperture 1
4, the air pressure in the drive side pressure chamber 5 rises rapidly near the end of the return stroke, which effectively acts as a brake against the large kinetic inertia force during the return stroke at high speed, and moves the piston 3 through the return stroke. Decelerate near the end. . In parallel with this, if the pressure in the drive side pressure chamber 5 increases to a predetermined high pressure, the pressure causes the relief valve 15 in the control valve 13 to
is opened, and the high pressure air in the drive side pressure chamber 5 is released to the atmosphere via the relief valve 15. This prevents the pressure in the drive-side pressure chamber 5 from becoming excessively increased, prevents the piston 3, etc. from rebounding, and prevents the return stroke speed of the piston 3, etc. from being decelerated more than necessary. It can be prevented. When the pressure in the drive-side pressure chamber 5 falls below the desired pressure due to the exhaust from the relief valve 15, the relief valve 15 closes again, and thereafter, as described above,
The high-pressure air in the drive-side pressure chamber 5 is gradually exhausted through the throttle 14 and the supply/exhaust switching valve 9, and the piston 3 and the like perform a return stroke at a low speed and return to the original position shown in the figure in a buffering manner. In this way, control valve 1
By the action of the throttle 14 and the relief valve 15 at 3, the piston 3 and the like return to their original positions as quickly as possible and in a cushioned manner. In addition, the above-mentioned supply/discharge switching valve 9
With the switching, the high-pressure air whose pressure has been set by the pressure reducing valve 10 is charged into the tank 12 and waits for the next drive, so that the drive stroke in the next cycle can be performed again with good start-up.

In the above embodiment, the pressure reducing valves 10 and 17 are provided between the high pressure air source 1 and the supply/exhaust switching valve 9, but the air pressure of the high pressure air source 1 is adjusted in advance to the pressure used for driving and returning the piston. If set, the pressure reducing valves 10 and 17 can be omitted.

Various structures can be adopted as the control valve 13, and an example of the structure is shown in FIGS. 2 and 3.

In FIGS. 2 and 3, the valve body 21 includes a valve port 22 and a cylinder port 23 connected to the supply/discharge switching valve 9 and the cylinder 2, respectively,
A check valve seat 24, a relief valve seat 25, and a throttle valve seat 2 that connect these ports 22 and 23 in parallel with each other.
6, and check valve seat 24.
is closed by the check valve body 27 biased by a spring 28 to form the check valve 16, and the relief valve seat 25 is closed by the relief valve body 30 in the piston 29 biased by the spring 31 to form the relief valve 15.
Further, the throttle valve seat 26 configures the throttle 14 so that its opening amount can be adjusted by a needle 32 rotatably screwed into the valve body 21. The high pressure air supplied to the valve port 22 opens the check valve body 27 against the biasing force of the spring 28, flows out from the check valve seat 24 to the cylinder port 23, and conversely flows into the cylinder port 23. Although the high-pressure air is prevented from flowing into the valve port 22 through the check valve 16, if the pressure is lower than a predetermined pressure, the opening amount is limited by the through hole 35 and needle 32 that communicate with the cylinder port 23. Throttle valve seat 26 and through hole 3 communicating with valve port 22
6, the high pressure air flows out into the valve port 22 in small amounts, and if the pressure of the high pressure air in the cylinder port 23 becomes higher than a predetermined pressure, the pressure flows through the back chamber hole 37, the back chamber 38, and the pressure chamber hole 39. Pressure chamber 4
0, moves the piston 29 upward together with the relief valve body 30 against the biasing force of the spring 31, opens the relief valve seat 25, and allows the high pressure air in the cylinder port 23 to flow out to the valve port 22. When the pressure in the cylinder port 23 decreases due to outflow, the relief valve 15 is closed again.

FIG. 4 is a diagram showing the results of an experiment conducted in the example of FIG. 1 under the following conditions.

Size of cylinder 2: φ40-1000mm Weight load 18: 60Kgf (horizontal movement) Size of piping between supply/discharge switching valve 9 and cylinder 2: φ12/9mm-2m Setting pressure of pressure reducing valve 10: 2Kgf/cm ² Pressure reducing valve 17 Setting pressure: 2Kgf/cm ² Equipment connection size: PT 1/8 inch (8A) Capacity of tank 12: 300cm ³ Opening amount of variable throttle 11: Cylinder 2 drive stroke speed set to 450mm/s Drive as shown in Figure 4 above In the graph showing the pressure change in the side pressure chamber 5, in the part A at the start of the drive stroke, the pressure in the drive side pressure chamber 5 is equal to or lower than the tank 1.
It shows that the pressure rises quickly and quickly due to the supply of high pressure air from the pressure reducing valve 10.
The figure shows that high-pressure air is supplied through meter-in control using the variable throttle 11.
In addition, in the return stroke, in the part C, the discharge of high pressure air from the drive side pressure chamber 5 is restricted by the throttle 14 of the control valve 13, thereby increasing the pressure in the drive side pressure chamber 5 and acting as a brake for the return stroke. The part D indicates that the pressure in the drive-side pressure chamber 5 is increased to a predetermined pressure or higher, and the relief valve 15 bypasses the pressure.

In addition, in the graph showing pressure changes in the return side pressure chamber 6, a portion E indicates that the pressure decreases due to switching of the supply/discharge switching valve 9, and a portion F indicates that the pressure decreases due to switching of the supply/discharge switching valve 9. This shows that high-pressure air flows into the return side pressure chamber 6 and its pressure rises rapidly, and the portion G shows that the return side pressure chamber 6 is maintained at approximately the set pressure. Furthermore, in the graph showing the speed and stroke of the piston, parts H and J indicate that the speed increases due to the air pressure from the pressure storage tank as the piston starts, and the constant velocity region is the variable throttle 11. This shows that the piston is driven at a constant velocity by meter-in control.

Note that the capacity of the tank 12 has a great influence on the start of the drive stroke, and if the capacity is too small, the cylinder 2 will not be able to start up properly and be driven.
On the other hand, if it is too large, it will cause a jump start, so
An appropriate one must be selected. That is, p/PV/V+v (1) V: Capacity of tank 12 (cm ³ ) v: Total dead volume between supply/discharge switching valve 9 and drive side pressure chamber 5 of cylinder 2 (cm ³ ) P: Set pressure of pressure reducing valve 10 (Kgf/cm ² ) p: Tank 12 at the initial stage of switching of supply/discharge switching valve 9
and can be supplied via variable aperture 11
In the state relational expression of pressure, V may be determined so that p is approximately equal to the substantial starting pressure of the cylinder 2. Therefore, V can be made smaller in proportion to v. Therefore, the volume of tank 12 in the above experiment was 300 cm ³
is determined by the above method.

[Effect of idea]

As described above, according to the drive device of the present invention, since the cylinder is driven by meter-in control, it is possible to perform a drive stroke at a good uniform speed, and at the time of starting, it is possible to use the auxiliary power stored in the tank in advance. Since it is assisted by high-pressure air, constant-speed drive with a good start-up is possible.Also, during the return stroke, high-pressure air is flowed into the return-side pressure chamber to speed up the return stroke, but the drive-side pressure is Since the exhaust from the chamber is restricted by the throttle of the control valve, the pressure in the drive side pressure chamber rises and acts as a brake against high-speed return near the end of the return stroke, effectively slowing down the return stroke. Furthermore, when the pressure in the drive side pressure chamber exceeds a predetermined pressure, the pressure is released to the atmosphere by a relief valve that bypasses the throttle, thereby preventing excessive pressure rise in the drive side pressure chamber. As a result, a rebound stroke can be prevented, and the return stroke can be prevented from being decelerated more than necessary, thereby making it possible to obtain a return stroke in an extremely rational manner, that is, in the shortest possible time and with a cushioning effect. Therefore, the driving of the cylinder can be synchronized with the constant speed traveling body, and the cylinder can be returned to the original position quickly and without any trouble.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is a cross-sectional view showing an example of the control valve, and Fig. 3 is its -
FIG. 4 is a diagram showing the experimental results of the above embodiment, and FIG. 5 is a schematic front view showing the concept of synchronously interlocking the piston rod with the constant speed vehicle. DESCRIPTION OF SYMBOLS 1... High pressure air source, 2... Cylinder, 5... Drive side pressure chamber, 6... Return side pressure chamber, 9... Supply/discharge switching valve, 11... Variable throttle, 12... Tank, 13
...control valve, 14...throttle, 15...relief valve, 16...check valve.

Claims (1)

[Scope of utility model registration request] A supply/discharge switching valve is provided in the flow path that communicates the high-pressure air source with the drive-side pressure chamber and the return-side pressure chamber of the cylinder, respectively, to alternately switch the communication between the two chambers between the high-pressure air source and the atmosphere. Between the high-pressure air source and the supply/exhaust switching valve in the flow path between the air source and the drive-side pressure chamber, from the high-pressure air source side, a variable throttle that controls the drive stroke of the cylinder in meter-in and assists in the activation of the drive stroke. Connect the pressure storage tanks in sequence,
Between the supply/discharge switching valve of the above flow path and the drive side pressure chamber,
Connect the control valve that controls the return stroke speed,
The above control valve is constructed by connecting in parallel a check valve that prevents high-pressure air from flowing out from the drive-side pressure chamber, a throttle that limits the flow, and a relief valve that operates near the end of the return stroke. Features: A synchronous cylinder drive device that can be driven synchronously with a constant speed running body.