JPS62132004A - Fluid pressure cylinder and its operation control circuit - Google Patents

Abstract

PURPOSE:To make a cylinder compact by forming a hydraulic chamber on the inner side of the blocked end of a piston rod and also a pneumatic chamber on the outer side of a cylinder tube and a guide rod in order to operate the cylinder by using air together with pressure oil. CONSTITUTION:The first pneumatic chamber 36 consists of a piston 35, a cylinder tube 32 and a guide rod 24, and the second pneumatic chamber 37 consists of the cylinder tube 32, a boss 30 and a piston rod 17. Also, a hydraulic chamber 39 is formed between a cap 38 and the guide rod 24. Therefore, a weight load set to a cylinder can be share by using air together with pressure oil, and a cylinder can be miniaturized and lightened in comparison with the conventional one.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fluid pressure cylinder suitable for, for example, a tire lift cylinder in an air inflator for a tubeless tire or a tire lift cylinder in a tire mounter, and its operation control circuit.

(Prior Art) For example, a tire lift cylinder in an air inflator for a tubeless tire lifts a tire carried under the inflator dome, presses it against the lower end of the dome to maintain the lift height, and as the tire is inflated. A function is required to firmly maintain the lift height against the reaction force of the tires and the downward biasing force of the dome.

Conventionally, there is a technique disclosed in Japanese Patent Publication No. 51-6401, for example, as a technique that meets such demands. That is, this publication discloses an air lift cylinder that is connected to an air regulator and whose operating pressure is set higher than the specified air pressure and blowing pressure of the tire.

(Problems to be Solved by the Invention) However, due to the compressibility of air in the air lift cylinders described above, it is difficult to use them under high loads, and this effectively limits the applicable tire size. In order to obtain a predetermined operating pressure, a cylinder with a large diameter is required, which poses the problem of increasing the size and weight of this type of device. Moreover, the problem with the above-mentioned lift cylinder is that because the lift height of the tire is too fixed during inflation, the compression force on the tire increases in proportion to the inflation displacement, resulting in a relative lack of air pressure or injected air. be. Furthermore, when the cylinder begins to descend after inflation, the tire quickly recovers its original shape due to the above pressure and engages with the wheel, generating a large vibration sound and at this time, the tire is interposed between the dome and the tire. There was a problem in that the residual air was exhausted, resulting in deterioration of the working environment and wasteful use of air.

By the way, in the lift cylinder, as a means for maintaining a predetermined lift height, the operating pressure of the cylinder is maintained in conjunction with a lift height confirmation switch, but with such a configuration, it is not possible to obtain an arbitrary lift height. This is difficult in practice and limits the applicable tire size. On the other hand, recently, cylinders equipped with a brake mechanism for maintaining an arbitrary lift height have been commercially available.

That is, this commercially available cylinder has a pair of biasing rings that can be press-contacted to the circumferential surface of the piston rod, a lever that can be displaced in the circumferential direction of the piston rod protrudes from one end of the ring, and control is provided to these levers. The cylinders are linked to press the biasing ring against the piston rod through the operation of the control cylinder to maintain the telescopic displacement of the piston rod.

However, with this type of structure, the braking force of the eccentric ring is limited, making it unsuitable for use under heavy loads.Moreover, due to the structure, the circumferential surface of the piston rod may be damaged and worn, resulting in There is a problem in that the braking force of the eccentric ring deteriorates over time, reducing its intended effect.

The present invention eliminates these conventional problems and makes full use of both air, which is easy to handle and simplifies equipment, as a working fluid, and hydraulic oil, which has excellent incompressibility. Apply pressure to accelerate its displacement, and when clamping the piston rod, apply hydraulic pressure against the load, and at the same time, force air into the cylinder to suppress piston rod operation and speed up the clamping action. It is an object of the present invention to provide a fluid pressure cylinder and its operation control circuit, which is capable of achieving accuracy and adjusting the contraction speed by increasing or decreasing the discharge speed of pressure oil when the piston rod is contracted.

(Means for Solving the Problems) Therefore, in the fluid pressure cylinder of the present invention, both ends of the cylinder tube having the second air supply port opened on the circumferential surface are connected to a head cover having a hollow guide rod and a rod flange. A hollow piston rod having one end closed and a piston disposed at the other end is slidably attached to the above-mentioned Gytro and Rad, and the closed end of the piston rod is capable of protruding outward from the rod flange, and A hydraulic chamber is formed inside the closed end, while a second pneumatic chamber is formed outside the cylinder tube and guide rod, communicating with a first pneumatic chamber partitioned by a piston and the second air supply port. a first air supply port that communicates with the first pneumatic chamber and an oil supply port that communicates with the hydraulic pressure chamber are opened on the circumferential surface of the head cover;
The cylinder is characterized by being smaller and lighter, and by reducing the amount of air consumed and the amount of pressure oil supplied and discharged required for cylinder operation.

Further, in the operation control circuit of the fluid pressure cylinder of the present invention, both ends of a cylinder tube having a second air supply port opened on the circumferential surface are closed by a head cover having a hollow guide rod and a rod flange, and the cylinder tube is provided with a hollow guide rod. A hollow piston rod having one end closed and a piston disposed at the other end is slidably mounted, the closed end of the piston rod is capable of protruding outward from the rod flange, and a hydraulic chamber is provided inside the closed end. On the other hand, a first pneumatic chamber defined by a piston and a second pneumatic chamber communicating with the second air supply port can be formed on the outside of the cylinder tube and the guide rod, and the peripheral surface of the head cover In this case, the first air supply port communicating with the first pneumatic chamber and the oil supply port communicating with the hydraulic pressure chamber are connected to the air supply passages of the first and second air supply ports of the fluid pressure cylinder. A solenoid valve that can open and close the oil passage is inserted, and an on/off unit consisting of a plurality of solenoid valves that can open and close the oil passage is inserted in the oil supply passage of the oil supply port, and when the cylinder is extended, the first air supply port It supplies air and pressure oil to the oil supply port, and when the cylinder is clamped, it supplies air to the second air supply port and closes the solenoid valve of the on-off unit, and when the cylinder is contracted, it is a part of the on-off unit. Alternatively, all the solenoid valves can be selectively opened and the contraction speed can be adjusted, thereby increasing the speed of extension, making the clamping operation faster and more accurate, and diversifying the contraction speed. There is.

(Example) Hereinafter, an illustrated example in which the present invention is applied to a tire lift cylinder in an air inflator for tubeless tires will be explained. It is a framed machine base, and the loading conveyor 5 is installed on the top of it.
A carry-out conveyor (path shown) is provided, and tubeless tires mounted on wheels serving as workpieces 6 are carried in and out.

A pedestal 8 is installed above the machine pedestal via a vertical frame 7, and a cylinder 9 is disposed facing downward on this pedestal 8. An inflator dome 11 is integrally connected to the piston rod 10 of the pedestal 8. A dome 11 is supported by a plurality of guide posts 12. A tubular tire presser 13 that can press the upper surface of the tubeless tire 6 is fixed to the lower end of the inflator dome 11, and a seal plate (as shown) that can be engaged with the upper edge of the wheel is provided inside the tire presser 13. is installed.

An air inlet communicating with the air pressure source 14 is provided between the outer peripheral edge of the seal plate and the inner peripheral surface of the tire presser 13, and a center cone that can move together with the piston rod 10 is provided in the center of the plate. 15 is disposed so as to be able to fit into the hub hole of the wheel disc.

On the other hand, inside the machine base 1, a lift cylinder 16 fixed immovably to the bridge frame 3 is installed, and its piston rod 17 is installed vertically upward. A mounting table 18 capable of accommodating the wheel is disposed at the upper end of the piston rod 17, and can be raised and lowered together with the expansion and contraction of the piston rod 17, while maintaining a constant arbitrary lift height. , is normally evacuated directly below the conveyance area of the loading/unloading conveyor 5 to enable tubeless tires 6 to be loaded and unloaded.

That is, as shown in FIGS. 3 to 5, the lift cylinder 16 has a head cover 21 with a first air supply port 19 and an oil supply port 20 opened on the circumferential surface of the upper end, and a cylindrical cylinder protruding inside the head cover 21. On the end face of the shaped boss 22, the first
An annular groove 23 communicating with the air supply port 19 is formed. At the center of the boss 22 is an elongated guide rod 2.
4 is integrally provided in a protruding manner, and the oil supply port 20 is provided inside the oil supply port 20.
A through hole 25 is formed which communicates with the guide rod 24, and one end thereof is open to the upper end surface of the guide rod 24.

Bridge frame 3 located above the head cover 21
Through the base plate 26 and the connecting bolt 27,
The rod flange 28 is fixed, and there are screws on the inner surface of this rod flange 28! - A boss 30 having a hole 29 through which the rod 17 can be inserted is provided, and an annular groove 31 is formed on the circumferential surface of the boss 30.

A cylinder tube 32 is airtightly attached to the small-diameter side circumferential surface of the annular groove 31, that is, the outer circumferential surface of the boss 30 and the outer circumferential surface of the boss 22, and is integrally connected to the cylinder tube 32 through a bolt 33. In the figure, 30a is a diameter-reduced portion formed at the tip of the boss 30, and a second air supply port 34 is opened at a corresponding position of the cylinder tube 32 facing this diameter-reduced portion 30a.

The piston rod 17 is made of an elongated tubular body, and its outer peripheral surface is fitted in the hole 29 in an airtight and slidable manner,
Further, the guide rod 24 is fitted onto the inner circumferential surface of the guide rod 24 in an oil-tight and slidable manner. And this piston rod 1
A piston 35, which is housed in a cylinder tube 32 in an airtight and slidable manner, is fixed to the lower end of the cylinder tube 32, and the piston 35 and the cylinder tube 32, as well as the guide rod 24 and the boss 22, A first pneumatic chamber 36 communicating with the supply port 19 is formed, and the piston 3
On the opposite side of 5, a second pneumatic chamber 37 is formed which communicates with the second air supply port 24 by the cylinder tube 32, boss 30, piston rod 17, etc.

In the figure, a piston rod cap 38 is fixed to the upper end of the piston rod 17 in an oil-tight manner, and three hydraulic chambers communicating with the through hole 25 are provided between the cap 38 and the upper end of the guide rod 24. is forming. 40 is a spacer integrally fixed to the upper end of the piston rod 17, and 41 is slidably supported via a guide block 43 that projects from the lower surface of the mounting table 18 and is fixed to the plate 26. A dog 44° 45 is fixed to the lower end of the slide shaft 42, and a switch 46° 47 for detecting the vertical position of the mounting table 18 is installed at a suitable position on the vertical frame 4 adjacent to the shaft 42. There is.

48.49 is an air supply pipe connected to the first and second air supply ports 19.34, 50 is an oil supply pipe connected to the oil supply port 20, and these are inserted into the control circuit shown in FIG. There is.

That is, the oil supply pipes 48 and 49 are separately connected to the ports of solenoid valves 52 that communicate with the air pressure source 51, and the flow directions of air within the valves 52 are set to be opposite to each other, and the flow directions are set to be opposite to each other. It is possible to switch according to the 152 positions.

The solenoid valve 52 is a 5-point/2-position switching valve, and when the piston rod 17 of the lift cylinder 16 is extended, the air supply pipe 48 is set to the air supply side, the air supply pipe 49 is set to the exhaust side, and the piston rod 17 is set to the air supply side and the air supply pipe 49 is set to the exhaust side. When the lift height is maintained and reduced, the air supply pipe 48 is set to the Tij air side and the air supply pipe 49 is set to the air supply side, and such valve position switching is controlled by the mounting table position sensor 53. has been done.

That is, the mounting table position sensor 53 is installed at a desired lift l-high position in the lifting area of the mounting table 18, and is normally kept in an OFF state to set the valve position of the solenoid valve 52 at a steady position, and the piston While promoting the elongation displacement of the rod 17, when detecting the set lift height of the mounting table 18, a control signal is output to the valve 52, and the valve 52 is, for example, energized to switch the position, thereby increasing the lift of the piston rod 17. It is designed to encourage high retention and reduction operation. In the figure, reference numerals 54 and 55 indicate flow rate regulating valves with check valves inserted into the air supply pipes 48 and 49.

On the other hand, an air-hydro converter 56 capable of generating oil pressure is connected to one end of the oil supply pipe 50, and an air pressure source 57 that can be shared with the air pressure source 51 is communicated with the converter 56, and an on/off unit is installed in the pipe. I am interjecting. The on/off unit 58 has three similar solenoid valves 59
, 60, 61 are connected in parallel with each other, and these valves 59, 60, 61 are composed of two-point, two-position switching valves, and one valve position allows oil to be supplied and discharged, and the other valve position The oil flow is cut off at the valve position.

That is, the five solenoid valves 60 and 61 are set to valve positions that allow oil supply and drainage when the piston rod 17 is extended and contracted, and are set to valve positions that cut off oil flow when the piston rod 17 maintains its lift height. The valve position is switched by the rack table position sensor 53 mentioned above.
The solenoid valve 59 can be selectively opened in response to a signal from the sensor 53.

That is, between the solenoid valves 59 and 60,
Flow rate regulating valves 62 with check valves are connected in parallel, and when the five valves are opened when the piston rod 17 is contracted, a small amount of hydraulic oil is sent to the five valves, and this is transferred to the air-hydro converter 56. I'm trying to bring it back inside. Therefore, in this case, the contraction or lowering speed of the screw I/N rod 17 can be adjusted in proportion to the throttle amount of the regulating valve 62.

In addition, in the figure, 63 is a pressure reducing valve, 64 is a solenoid valve that opens and closes the air supply path between the air-hydro converter 56 and the air pressure source 57, 65 is a relief valve, 66 is a closing valve, and 67
68 is a hydraulic oil contained in the air-hydro converter 56, and an air pipe 68 is connected between the hydro-converter 56 and the air pressure source 57.

(Function) The lift cylinder 16 that makes full use of the fluid pressure cylinder configured as described above is normally supplied with the first and second air supplies 19.
The supply of air to 34 is stopped, and the supply of hydraulic oil 67 to oil supply port 20 is also stopped.

Therefore, the piston rod 17 is shrunk as shown in FIG. 4, and the loading platform 18 fixed to the upper end of the rod 17 via the piston rod cap 38 is mounted on the loading conveyor 5 as shown in FIG. Evacuate to the lowest position below the transport area,
This allows the conveyor 5 to transport tubeless tires 6.

Meanwhile, in the lift cylinder 16, the piston 35 fixed to the lower end of the piston rod 17 comes into contact with the inner end surface of the head cover 21, as shown in FIG. 4, and closes the groove 23 formed in the end surface of the boss 22. , and the first pneumatic chamber 36 that communicates with the 71123 has disappeared, and the second pneumatic chamber 36 has disappeared.
The volume of the pneumatic chamber 37 has been increased.

Further, at the upper part of the piston rod 17, as the rod 17 contracts, the piston rod cap 38 approaches the upper end of the guide rod 24, thereby minimizing the volume of the hydraulic chamber 39 formed therebetween.

Under these circumstances, the air inflator is started,
When the tubeless tire 6 mounted on the wheel is carried from the carry-in conveyor 5 to a fixed position directly under the inflator dome 11, the tire 6 is moved by the lift cylinder 16.
lift-up is performed.

In preparation for its lift-up operation, the lift cylinder 16
The solenoid valve 64 inserted into the air supply pipes 48, 49, the air supply pipe 68, the oil supply pipe 50, etc. is opened, and air can be pumped from the pneumatic source 51 to the solenoid valve 52, and air can also be fed from the pneumatic source 57. Air is forced into the air-hydro converter 56, and the hydraulic oil 67 housed therein is pressurized so that the hydraulic oil 67 can be forced into the on-off unit 580 and each solenoid valve 59, 60, 61. . In this case, the air-hydro converter 56 is used as the hydraulic pressure generating means as described above, and the conventional hydraulic power unit consisting of a hydraulic pump, motor, etc. is not required, so the separate side is simple and the piping structure is simple. becomes.

Therefore, when lifting up the lift cylinder 16, the solenoid valve 52 and each solenoid valve 59, 60, 61 of the on/off unit Σ are operated, and air and hydraulic oil 67 are supplied to one first air supply port and one oil supply port 20. is pumped. Among these, when the valve position of the solenoid valve 52 is switched to the extension side of the piston rod 17 and the air supply pipe 48 is communicated with the air pressure source 51 and the other air supply pipe 49 is opened to the atmosphere, air is transferred to the air pressure source 51. The air is then guided from the air supply pipe 48 to the first air supply port 19 via a solenoid valve 52, a one-way check valve, and a flow rate adjustment valve 54.

The air that has flowed into the first air supply port 19 is guided through a passage formed inside the head cover 21 into a concave groove 23 formed on the inner end surface of the boss 22, and the piston that closes the groove 23. Pneumatic pressure is applied to the lower end surface of 35. When the pressure in the groove 23 gradually increases and reaches a constant pressure, the piston 35 is fixed to the piston rod 17, the piston rod cap 38 fixed to the upper end of the rod 17, the mounting table 18, etc. and the weight of the tubeless tire 6 housed on the loading table 18, and the piston rod 17 protrudes upward.

When the piston 35 moves upward, the closed state of the groove 23 is released, and a first pneumatic chamber 36 as shown in FIG. 6 is formed between the lower end surface of the piston 35 and the inner end surface of the head cover 21. Air flows into the chamber 36 and applies its pressure to the lower end surface of the piston 35. In this case, the pressure-receiving area of the piston 35 is the sum of the entire lower end surface of the piston 35 and the lower end surface of the piston rod 17, and is significantly increased compared to the state immediately before the piston 35 starts moving upward as shown in FIG. Therefore, when the pressure in the first pneumatic chamber 36 is gradually increased, the pressure acting on the piston 35 is multiplied.
The upward movement of the piston 35 is prompted by breathing, and the piston rod 1
The mounting table 18 or the tubeless tire 6 that moves together with the tubeless tire 7 is rapidly lifted up.

Moreover, in this case, the volume of the first pneumatic chamber 36 gradually increases,
Accordingly, the volume of the second pneumatic chamber 37 gradually decreases, and the air remaining in the chamber 37 is pushed out and discharged from the second air supply port 34 to the atmosphere through the air supply pipe 49 and the solenoid valve 52. Ru.

On the other hand, before and after the switching operation of the solenoid valve 52, each solenoid valve 59 in the shadow of the on-off unit Σ
, 60, 61 are opened, the pressure oil in the air-hydro converter 56 is guided from the oil supply pipe 50 to the oil supply port 20 through the respective valves 59, 60, 61.

The pressure oil that has flowed into the oil supply port 20 is transferred to the head cover 21
The oil pressure is guided to the hydraulic chamber 39 through the through hole 25 formed inside the guide rod 24, and the hydraulic pressure is applied to the piston rod 17.
It acts on the inner end surface of the piston rod cap 38 fixed to the upper end of the piston rod cap.

Therefore, through the pressure action on the piston rod cap 38, the piston rod 17 to which the rod collar 138 is fixed is promoted to extend, and in combination with the above-mentioned pneumatic action, the inside of the cylinder tube 32 is substantially moved. The entire area corresponds to the pressure receiving area, and the upward movement of the piston 35 and the piston rod 1
Rapidly promotes the elongation displacement of 7. Therefore, the lift-up speed of the mounting table 18 or the tubeless tire 6 is increased, speeding up the air inflator operation on the tubeless tire 6 is promoted, and as the elongation displacement of the piston rod 17 increases, the first pneumatic chamber 36 At the same time, the volume of the hydraulic chamber 39 gradually increases as shown in FIG.

In this way, when the elongation displacement of the piston rod 17 gradually increases and the mounting table 18 or the tubeless tire 6 is lifted up, the hub hole (not shown) of the wheel disc engages with the center cone 15 at the mid-high position. ,
The tires 6 are aligned. Piston rod 17
When the mounting table 18 is lifted up by further elongation, the upper edge of the tubeless tire 6 on the table 18 comes into contact with the upper edge of the tire presser 13, and the bead of the tire 6 is pushed down, causing the wheel to An air inlet is formed between the rim portion and the rim portion.

Then, around this time, when the lift-up height of the mounting table 18 is detected by the mounting table position sensor 53, a control signal is output from the sensor 53, and this is applied to each of the solenoid valves 52 and the on/off unit 58. It is sent to solenoid valves 59, 60, and 61. The solenoid valve 52 switches its valve position from the lift-up side to the lift-up holding side or the piston rod 17 contraction side in response to the control signal, and as shown in FIG. 5, the communication between the air supply pipe 48 and the air pressure source 51 is cut off. and the pneumatic source 51
The extension operation of the piston rod 17 is stopped, and on the other hand, the air supply pipe 49 and the air pressure source 51 are brought into communication with each other, and the lift cylinder 16 shifts to a lift-up holding operation.

That is, when the four air supply pipes communicate with the air pressure source 51, air flows from the solenoid valve 52 to the flow rate adjustment valve 55 with a check valve.
The air is then led to the second air supply port 24 from four air supply pipes. The air flowing into the air supply port 24 is transferred to the boss 3
It is guided to the second air pressure chamber 37 through the gap between the reduced diameter portion 30a of 0 and the inner circumferential surface of the cylinder tube 32, and the pressure in the chamber 37 is gradually increased to apply the air pressure to the upper end surface of the piston 35.
The pressure in the first pneumatic chamber 36 is opposed.

On the other hand, the on-off unit 580 each solenoid valve 59
, 60, 61, the valves 59, 60, 61 switch their positions to the pressure oil supply stop side and close, as shown in FIG. For this reason,
One end of the oil supply pipe 50 is closed, and the hydraulic chamber 39 and the through hole 25 in the lift cylinder 16 that communicate with the oil supply pipe 50 and the chain pipe 50 are sealed, thereby preventing the pressure oil contained therein from flowing out. .

Therefore, the volumes of the three hydraulic chambers are maintained at the same amount as just before the lift-up stop, and the piston rod 17 maintains the displacement just before the lift-up stop via the hydraulic pressure, so that the loading table 18 or the tubeless tire 6 can be moved to the desired position. The lift-up height is maintained, and the tubeless tire 6 can be used for the air inflator work that will be performed later.

When the piston rod 17 is clamped by such pressure oil, the valves 59 and 60 are closed due to the response speed of the pressure oil.
．． Even after switching 61, the screw 1-rod 17 is allowed to extend slightly, resulting in a so-called overshoot of the clamp position, which becomes an obstacle to increasing the speed of the clamping action and increasing the precision of the clamp position. However, in this case, as described above, the pressure in the second pneumatic chamber 37 formed in synchronization with the clamping action opposes the piston 35, and the air flows at a higher speed than the hydraulic oil. The chamber 37 is quickly formed to suppress or brake the upward movement of the piston 35, eliminate the above-mentioned obstruction caused by the pressure oil, prevent the above-mentioned overshoot, and increase the speed of the clamping action and the accuracy of the clamping position. You will get it.

In this case, one end of the air supply pipe 48 is connected to the solenoid valve 5.
Since the air in the first pneumatic chamber 36 is opened to the atmosphere through the boat No. 2, the air in the first pneumatic chamber 36 that is pushed away by the piston 35 due to the overshoot suppressing action is transferred from the air supply pipe 48 to the flow rate adjustment valve 54 with a check valve. After that, it is discharged from the solenoid valve 52.

Under such a lift-up clamped state of the lift cylinder 16, air is injected into the tubeless tire 6 from the pneumatic source 14 via the air inflator dome 11 and the formed air inlet. The tubeless tire 6 expands as air is injected, increasing the reaction force against the tire presser 13 and exerting a downward reaction force on the mounting table 18 to push it down.

On the other hand, with this air injection method, the volume of the tire 6 is intentionally reduced by the amount that the rim portion of the tubeless tire 6 is bent inward by the tire presser 13, and when the tire 6 returns to its original shape, the air is injected. Insufficient injection or a slight drop in tire pressure cannot be avoided.

In such a case, in the present invention, depending on the degree of reduction in the tire air pressure based on the size and material of the tubeless tire 6, for example, if the degree of pressure reduction is expected to exceed a permissible value, the mounting table position sensor 53 selectively outputs a control signal, and sends this to a specific valve of the on-off unit Σ, to a solenoid valve 59 in the embodiment, to open the five valves.

That is, when the solenoid valve 59 is opened, a part of the pressure oil sealed in the three hydraulic chambers etc. passes from the oil supply pipe 50 to the flow rate adjustment valve 62 with a check valve, and then from the solenoid valve 59 to the oil supply pipe 50. Air-hydro converter 56
will be returned to. Therefore, as the pressure oil is discharged, the pressure oil stored in the hydraulic chamber 39 and the like decreases, and the piston rod 17 contracts by the amount of the decrease against the above-mentioned oil pressure.

In this case, the speed of contraction of the piston rod 17, in other words, the speed of descent of the tubeless tire 6 on the mounting table 18, is related to the weight of the tubeless tire 6, the viscosity of the hydraulic oil 67, and the amount of oil discharged. Since the amount of oil discharged can be adjusted by adjusting the throttle angle of the flow rate adjustment valve 62 with a check valve, the above-mentioned lowering speed can be adjusted through this adjustment. Therefore, by adjusting the descending speed of the tubeless tire 6 to, for example, substantially the same speed as the inflation displacement speed of the tire 6, the reaction force of the tire 6 acting on the mounting table 18 is kept substantially uniform, and the amount of air to be injected is By gradually closing the air inlet in response to the specified amount of air injection, and by closing the air inlet when the specified amount is injected and releasing the pressure from the tire presser 13, it is possible to prevent the tire air pressure from decreasing.

Moreover, by gradually lowering the mounting table 18 as described above, the engagement between the bead portion of the tire 6 and the rim portion of the wheel is performed slowly after the specified amount of air is injected. Not only can the impact and vibration noise of the tire 6 be reduced, but also the amount of residual air interposed between the bead part of the tire 6 and the rim part of the wheel can be reduced, and the consumption of air associated with its discharge can be reduced. You will get it.

In this way, when a predetermined amount of air is injected into the tubeless tire 6, a control signal is output from the position sensor 53, which is transmitted to the solenoid valve 6 in the shadow of the on/off unit 1.
0.61, and these valves 60.61 are opened. Therefore, the pressure oil in the hydraulic chamber 39, etc. is returned to the air-hydro converter 56 from the valves 60, 61, and the piston rod 17 contracts in accordance with the amount of oil discharged, and the mounting table 18 is moved to its lowest position. After positioning, the tubeless tire 6 on the table 18 is transferred to the carry-out conveyor. The air in the first pneumatic chamber 36 that is displaced by the downward movement of the piston 35 is discharged from the air supply pipe 48 to the atmosphere through the solenoid valve 52.

(Effects of the Invention) As described above, in the fluid pressure cylinder of the present invention, both ends of the cylinder tube having the second air supply port opened on the circumferential surface are closed with the head cover having the hollow guide rod and the rod flange. A hollow piston rod having one end closed and a piston disposed at the other end is slidably attached to the guide rod, the closed end of the piston rod is capable of protruding outward from the rod flange, and the closed end is arranged inside the closed end. A hydraulic chamber is formed in the head cover, while a first pneumatic chamber defined by a piston and a second pneumatic chamber communicating with the second air supply port can be formed outside the cylinder tube and the guide rod. A first air supply port that communicates with the first pneumatic chamber and an oil supply port that communicates with the hydraulic chamber are opened on the circumferential surface of the cylinder, and the load imposed on the cylinder is shared by using both air and pressure oil. Therefore, compared to conventional air cylinders or hydraulic cylinders, it can be made smaller and lighter, and the amount of air consumed and the amount of pressure oil supplied and discharged required for cylinder operation can be reduced, and those pressure sources can be reduced. This has the effect of making it more compact.

Further, as described above, the operation control circuit for the fluid pressure cylinder of the present invention includes closing both ends of the cylinder tube with the second air supply port opened on the circumferential surface with a head cover having a hollow guide rod and a rod flange. A hollow screw I with one end closed and a piston installed on the other end of the guide rod.
A closed end of the piston rod is slidably mounted, a closed end of the piston rod is capable of protruding outward from the rod flange, and a hydraulic chamber is formed inside the closed end, while a hydraulic chamber is formed outside of the cylinder tube and the guide rod. A first pneumatic chamber defined by a piston and a second pneumatic chamber communicating with the second air supply port can be formed, and a first air pressure chamber communicating with the first pneumatic chamber is formed on the circumferential surface of the head cover. The first and second hydraulic cylinders each have an oil supply port that communicates with the hydraulic chamber.
A solenoid valve that can open and close the air supply path is inserted in the air supply path of the air supply port, and an on/off unit consisting of a plurality of solenoid valves that can open and close the oil path is inserted in the oil supply path of the oil supply port. When the cylinder is inserted and the cylinder is extended, air and pressure oil are supplied to the first air supply port and the oil supply port, and these pressures are combined to perform the extension operation, so it is possible to speed up the above operation. can.

In addition, when the fluid pressure cylinder and ring are clamped, the solenoid of the on/off unit is closed, and air is force-fed to the second air supply port to suppress transient expansion of the cylinder caused by pressure oil. , it is possible to accelerate the clamping action, prevent overshoot of the piston wood, and ensure the accuracy of the clamping position.

Furthermore, when the cylinder is compressed, some or all of the solenoid valves in the on-off unit are selectively opened, and the contraction speed can be adjusted, so it can be used, for example, in a tire lift cylinder or tire mount in an air inflator for tubeless tires. This has a favorable effect on the operation control circuit of the tire lift cylinder.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of an air inflator for tubeless tires to which the present invention is applied, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a plan view showing main parts of the cylinder according to the present invention. FIG. 4 is a longitudinal cross-sectional view showing the essential parts of the cylinder according to the present invention, showing its reduced state, and FIG. 5 is a circuit diagram showing an example of the control circuit according to the invention, showing the cylinder in a clamped state. , FIG. 6 is a vertical cross-sectional view showing the main part of the cylinder according to the present invention, and shows its extended operating state. 17...Piston rod. One...first air supply port. 20...Oil supply port, 21...Head cover. 24...Guide rod. 32...Cylinder tube. 34...Second air supply port. 35... Piston, 36... First pneumatic chamber. 37...Second pneumatic chamber, 3...Hydraulic chambers. 52.59.60.61... Solenoid valve 58.
...On-off unit patent applicant Nissan Motor Sales Co., Ltd. Figure 1 Z Figure 2

Claims (2)

[Claims] (1) Both ends of a cylinder tube with a second air supply port opened on the circumferential surface are closed with a head cover having a hollow guide rod and a rod flange, one end is closed with the guide rod and a piston is provided at the other end. A hollow piston rod is slidably attached thereto, and a closed end of the piston rod is capable of protruding outward from the rod flange, and a hydraulic chamber is formed inside the closed end, while the cylinder tube and guide rod A first pneumatic chamber defined by a piston and a second pneumatic chamber communicating with the second air supply port can be formed on the outside of the head cover, and a second pneumatic chamber communicating with the first pneumatic chamber can be formed on the circumferential surface of the head cover. A fluid pressure cylinder characterized in that an oil supply port communicating with a first air supply port and a hydraulic chamber is opened. (2) Both ends of a cylinder tube with a second air supply port opened on its circumferential surface are closed with a head cover having a hollow guide rod and a rod flange, one end of which is closed with the guide rod, and a piston is provided at the other end. A hollow piston rod is slidably attached thereto, and a closed end of the piston rod is capable of protruding outward from the rod flange, and a hydraulic chamber is formed inside the closed end, while the cylinder tube and guide rod A first pneumatic chamber defined by a piston and a second pneumatic chamber communicating with the second air supply port can be formed on the outside of the head cover, and a second pneumatic chamber communicating with the first pneumatic chamber can be formed on the circumferential surface of the head cover. A solenoid valve capable of opening and closing the air supply passages is inserted into the air supply passages of the first and second air supply ports of the fluid pressure cylinder, which has an oil supply port that communicates with the first air supply port and the hydraulic chamber. In addition, an on/off unit consisting of a plurality of solenoid valves that can open and close the oil passage is inserted in the oil supply passage of the oil supply port, and when the cylinder is extended, air and pressure oil are supplied to the first air supply port and the oil supply port. When the cylinder is clamped, air is supplied to the second air supply port and the solenoid valve of the on-off unit is closed, and when the cylinder is contracted, some or all of the solenoid valves of the on-off unit are selectively opened. An operation control circuit for a fluid pressure cylinder, characterized in that the reduction speed thereof can be adjusted.