Fluid pressure cylinder apparatus having throttle valve

A cylindrically shaped valve rod is housed in a valve hole formed in a cylinder body in a manner so as to be rotatable around a center axis line, and a connecting hole having a first hole opening that is allowed to communicate with a first flow path hole, and a second hole opening that is allowed to communicate with a second flow path hole is formed in the valve rod. A flow adjusting groove that is extending in a circumferential direction around an outer periphery of the valve rod from a position of the first hole opening is formed, and the flow adjusting groove is formed such that a groove width gradually narrows toward a tip end side and the groove depth gradually shallows at the same time, so that the valve opening extent is adjusted along with rotating operation of the valve rod.

TECHNICAL FIELD

The present invention relates to a fluid pressure cylinder apparatus having a throttle valve, in which a fluid pressure cylinder is provided with a throttle valve, and a movement control of a piston is performed by means of adjusting a flow of pressurized fluid with the throttle valve.

BACKGROUND ART

Hitherto, as this kind of fluid pressure cylinder apparatus having a throttle valve, an apparatus in which a moving speed of a piston is controlled by adjusting a flow of pressurized fluid supplied to or discharged from a pressure chamber with a throttle valve, an apparatus in which the piston is stopped at an end of stroke in a buffered manner by means of limiting a flow of fluid discharged from a pressure chamber with a throttle valve when the piston approaches the end of the stroke, or the like is known.

In such a cylinder apparatus, generally, as the throttle valve, a variable throttle valve configured to adjust a square measure of an opening of an orifice by advancing and retreating a cone-shaped valve rod is used and the variable throttle valve is attached to a cylinder body.

InFIG. 9, a main part of the conventional fluid pressure cylinder apparatus provided with such a variable throttle valve50is illustrated. This cylinder apparatus includes a cushion chamber56other than a pressure chamber52in an inner part of a cylinder body51, in which the cushion chamber56is interrupted from the pressure chamber52by means of a collaborative action of a rod54and a sealing member55when the piston53approaches the end of the stroke, whereas the cushion chamber56is allowed to communicate with the pressure chamber52when the piston53is in the middle of the stroke, and a port (not shown) is formed so as to be allowed to communicate with the cushion chamber56. In addition, after the cushion chamber56is interrupted from the pressure chamber52, the fluid in the pressure chamber52flows into the cushion chamber56via a through-hole58bfrom a through-hole58a, while receiving a limit of flow by the throttle valve50, and is discharged from the port. Thereby, the piston53is configured to be stopped at the end of the stroke in the buffered manner.

The throttle valve50is constructed such that a valve holder60is attached to a valve hole59formed in the cylinder body51, and a valve rod61provided with a cone-shaped adjusting portion61aat a tip end thereof is movably mounted in the valve holder60in an advancing and retreating manner in a direction of an axis line of the valve hole59upon rotating operation. In addition, at a base end portion61bwhere a male screw of the valve rod61is provided, a lock nut63for preventing the valve rod61from being rotated by vibration or the like after the square measure of the opening is adjusted is attached.

In the conventional fluid pressure cylinder apparatus, the throttle valve attached to the cylinder body is configured to adjust the square measure of the opening of the orifice by means of advancing and retreating the valve rod in the direction of the axis line. Accordingly, a dimension of the valve rod in a direction along the axis line is large, and in addition, an operating area for advancing and retreating the valve rod has to be secured. Consequently, there has been a large limitation on downsizing.

Further, there has also been a problem that when the valve rod, the valve holder, the lock nut, or the like is widely protruding outward of the cylinder body, it tends to be impeditive for treating the cylinder, or for attaching other devices in the vicinity of the cylinder.

DISCLOSURE OF INVENTION

An object of the present invention is to provide a fluid pressure cylinder apparatus having a throttle valve configured for a throttle valve to be compactly attached to a cylinder body by means of miniaturizing and simplifying the throttle valve.

So as to achieve the above-described object, according to the present invention, the fluid pressure cylinder apparatus having a throttle valve, including a piston moving in an inner part of a cylinder body by means of action of the fluid pressure, a pressure chamber for exerting the action of the fluid pressure on the piston, a port for supplying or discharging a pressurized fluid to the pressure chamber and a variable throttle valve for adjusting a flow of the pressurized fluid so as to control a movement of the piston is provided. The throttle valve includes a cylindrically shaped valve rod housed in a circular valve hole formed in the cylinder body in a condition of being hooked in a direction of a center axis line of the valve hole, while being rotatable around the center axis line of the valve hole. A first flow path hole and a second flow path hole for the pressurized fluid is opened at a side face and a bottom face of the valve hole, and the valve rod is formed such that an outer peripheral surface is formed in a manner so as to be in close sliding contact with an inner peripheral surface of the valve hole. Further, a connecting hole whose first hole opening at one end is opened at a side face of the valve rod and is allowed to communicate with the first flow path hole, and a second hole opening at the other end is opened at a bottom face of the valve rod and is allowed to communicate with the second flow path hole is formed in an inner part of the valve rod. Furthermore, a flow adjusting groove for adjusting a connected square measure of the first flow path hole and the first hole opening along with a rotating operation is provided at an outer periphery of the valve rod, and the flow adjusting groove extends in a circumferential direction from a position of the first hole opening as a base end and a groove width gradually narrows toward a tip end side and a groove depth gradually shallows at the same time.

In the present invention, the valve rod is preferable to be disposed in the valve hole in a non-protruding condition, and a device for hooking the valve rod in the valve hole is preferable to be a ring-shaped stopping ring.

In a concrete embodiment of the present invention, the throttle valve is provided with a function as a speed control valve for controlling a moving speed of the piston, and either one of the first flow path hole or the second flow path hole is allowed to communicate with the port, and the other is allowed to communicate with the pressure chamber.

In another concrete embodiment of the present invention, the throttle valve is configured to be provided with a function as a cushion valve for stopping the piston at an end of a stroke in a buffered manner, and when the piston approaches the end of the stroke, a fluid in the pressure chamber at a discharge side is discharged from the port through the throttle valve.

More in detail, a cushion chamber is formed in an inner part of the cylinder body, in which when the piston is in the middle of the stroke, the cushion chamber is allowed to communicated with the pressure chamber, whereas the cushion chamber is interrupted from the pressure chamber when the piston approaches the end of the stroke. Further the port is allowed to communicate with the cushion chamber and one and the other of the first flow path hole and the second flow path hole of the throttle valve are respectively allowed to communicate with the cushion chamber and the pressure chamber.

According to the present invention, since the throttle valve for adjusting a flow is configured such that the flow can be adjusted only by rotating the valve rod around its axis line in the valve hole, the throttle valve can be constructed at a compact and simple structure with small number of parts in comparison with the conventional throttle valve that advances and retreats the valve rod in a direction of the axis line, and the throttle valve can be compactly assembled in the fluid pressure cylinder.

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 1 through 3show the first embodiment of a fluid pressure cylinder apparatus having a throttle valve, and a cylinder apparatus1A of the first embodiment is constructed such that a variable throttle valve3for controlling a movement of a piston13by means of adjusting a flow of pressurized fluid is attached to a fluid pressure cylinder2, and the piston13is stopped at an end of the stroke in a buffered manner by means of causing to function the throttle valve3as a cushion valve.

As is clear fromFIG. 2, the fluid pressure cylinder2includes a cylinder body10having a circular cross-section, and a circular cylinder hole11that is extending in a direction of an axis line L is formed in an inner part of the cylinder body10. One end of the cylinder hole11is closed by an end wall10athat is integrally formed with the cylinder body10, and the other end thereof is opened. The end portion of the cylinder hole11being opened is sealed by an end cover12, which is air-tightly attached to an end portion of the cylinder body10. Further, the piston13is movably housed in the direction of the axis line L, to be moved by means of action of fluid pressure, in an inner part of the cylinder hole11. Furthermore, the shape of the cross-section of the cylinder body10may be a rectangular shape.

A piston rod14is extended from one end of the piston13in the direction of the axis line L, and the piston rod14is protruding outward while slidably penetrating the end cover12. A numeral15denotes a sealing member attached to the end cover12, for sealing a gap between the end cover12and an outer peripheral surface of the piston rod14. In addition, at the other end of the piston13, a sealing member16for interrupting between a first pressure chamber18, described later, and a cushion chamber20when in a cushioning action is extended in the direction of the axis direction L. The sealing member16is integrally formed with the piston rod14, and is formed by means of causing part of the piston rod14to be extended from the piston13. The length of the sealing member16is short, and is in an extent of about one fourth of a hole-length of the cylinder hole11, in an example of the illustration.

At both ends of the piston13, two of the first and second pressure chambers,18and19, for exerting the action of the fluid pressure to the piston13are formed. In the above, the first pressure chamber18is formed between the piston13and the end wall10a, and is allowed to communicate with the cushion chamber20having a small diameter, which is formed at the end wall10a. The first pressure chamber18is allowed to communicate with a first port21formed at a side surface of the cylinder body10through the cushion chamber20. The throttle valve3is provided in a manner so as to intervene in a flow path that connects the first pressure chamber18and the cushion chamber20as described later in detail. On the other hand, the second pressure chamber19is formed between the piston13and the end cover12, and is allowed to communicate with a rod insertion hole23formed in the end cover12. The second pressure chamber19is allowed to communicate with a second port22formed at a side surface of the end cover12through the rod insertion hole23.

Accordingly, when the second pressure chamber19is thrown open outward through the second port22from a movement condition shown inFIG. 1and the pressurized fluid such as air or the like is supplied to the first pressure chamber18from the first port21through the cushion chamber20, the piston13and the piston rod14are moved (advanced) in a left direction shown inFIG. 1. Further, when the cushion chamber20and the first pressure chamber18are thrown open outward through the first port21, and the pressurized fluid is supplied to the second pressure chamber19from the second port22, the piston13and the piston rod14are moved (retreated) in a right direction shown inFIG. 1.

Furthermore, when the piston13approaches an end of the stroke in the retreating stroke of the piston13, as shown inFIG. 1, the sealing member16fits into the cushion chamber20, and is in sliding contact with a cushion packing25attached to an inner peripheral surface of the cushion chamber20in an air-tight manner. Thereby, the cushion chamber20and the first pressure chamber18are interrupted from each other. As a result, the fluid in the first pressure chamber18that is freely discharged from the first port21through the cushion chamber20until then is brought to be discharged through the cushion chamber20and the first port21in a condition for the flow thereof to be limited because of flowing through the throttle valve3. Accordingly, a cushioning action is created by this operation and the piston13stops at the end of the stroke in the buffered manner.

The cushion packing25is a lip-type seal having a one-way sealing function, and interrupts a flow of the fluid in the reverse direction, i.e., the flow that is directed from the first pressure chamber18to the cushion chamber20in a condition being in contact with an outer periphery of the sealing member16, whereas the cushion packing25allows the flow in the forward direction, i.e., the flow that is directed from the cushion chamber20to the first pressure chamber18. Accordingly, when the pressurized fluid is supplied from the first port21to the cushion chamber20at a time when the piston13is advanced from the movement condition shown inFIG. 1, the pressurized fluid freely flows into the first pressure chamber18while pushing open the cushion packing25. The starting up operation is thereby smoothly performed.

The variable throttle valve3is attached to a side face of the cylinder body10and is constructed as follows. That is, as clear fromFIG. 3, at a side face of the end wall10aof the cylinder body10, a circular valve hole30is formed in a direction orthogonal to the axis line L of the cylinder body10in a manner so as to be directed to a center of the cushion chamber20, and a cylindrically shaped valve rod31is attached in the valve hole30.

The valve hole30is composed of a small diameter hole portion30apositioned at a backside of the valve hole30and a large diameter hole portion30bpositioned outside the valve hole30. At a side face of the small diameter hole portion30a, a first flow path hole33connected to the first pressure chamber18is opened, and at a center position of a bottom face of the small diameter hole portion30a, a second flow path hole34connected to the cushion chamber20is opened.

On the other hand, the valve rod31is, as clear fromFIGS. 4aand4b, composed of a main shaft portion31ahaving a small diameter, which fits into the small diameter hole portion30ain a condition of being in closely sliding contact with an inner peripheral surface of the small diameter hole portion30a, and an operating portion31bhaving a large diameter, which fits into the large diameter hole portion30bin a non-protruding condition. The valve rod31is disposed in the valve hole30in a condition that the valve rod31is hooked at the valve hole30in a direction of a center axis line M of the valve hole30, whereas the valve rod31is capable of being freely rotated around the center axis line M of the valve hole30(namely, a center axis line of the valve rod31). Further, an operating hole39having an angular hole shape, such as for example, a hexagonal hole, or the like for rotating operation using a tool, such as a wrench, or the like is formed at center portion of a top face of the operating portion31b.

As a hooking device for hooking the valve rod31in the valve hole30, a hooking member38composed of a ring-shaped stopping ring shown inFIG. 5is used in the illustrated embodiment. The hooking member38is composed of a ring-shaped main body portion38aand a plurality of hooking pieces38bextending like a spokes of a wheel from an outer periphery of the main body portion38a. These hooking pieces38bare elastically hooked on a hole wall of the valve rod30outward, and the main body portion38ais slidably in contact with an upper face of the valve rod31. In this case, it is preferable that a jaw portion formed of a groove or a step where a tip end of the main body portion38ais hooked is formed at the valve wall of the valve rod30.

However, the hooking device is not limited to the member that is separately formed like the hooking member38. For example, a construction in which a hooking groove in a circumferential direction is formed in an inner peripheral surface of the valve rod30, and a projection formed on an outer periphery of the valve rod31is movably hooked on the hooking groove may be applicable.

In an inner part of the valve rod31, a connecting hole40for connecting the first flow path hole33and the second flow path hole34is formed. A first hole opening40aof one end of the connecting hole40is opened at a position between two sealing members,41and41, at a side face of the main shaft portion31a, and is capable of communicating with the first flow path hole33. A second hole opening40bof the other end of the connecting hole40is opened at a bottom face of the main shaft portion31aand is allowed to constantly communicate with the second flow path hole34.

Further, a flow adjusting groove42for adjusting a connected square measure of the first hole opening40aof the connecting hole40and the first flow path hole33is formed on an outer peripheral surface of the main shaft portion31a. The flow adjusting groove42extends in a circumferential direction around the outer peripheral surface of the main shaft portion31afrom a position of the first hole opening40aas a base end, and the groove width gradually narrows toward the tip end side thereof while the groove depth gradually shallows at the same time between two of the sealing members,41and41. Although a groove shape of the flow adjusting groove42is formed of a V-shaped cross-section in the drawing, other arbitrary cross-section shape, such as a U-shape, a concavity-shape, a trapezoid, or the like may be applicable.

The thus constructed variable throttle valve3adjusts the flow of the pressurized fluid by means of varying the connected square measure (valve opening extent) of the first hole opening40aof the connecting hole40and the first flow path hole33upon rotating the valve rod31. That is, as shown in FIG.6a, when the first hole opening40aand the first flowing path hole33are directly and perfectly allowed to communicate with each other, the throttle valve3is in a fully open condition and the flow is maximized. When the valve rod31is rotated clockwise as shown inFIG. 6b, from the above condition, the valve opening extent is gradually reduced and the flow is correspondingly limited. This is because the first hole opening40ais allowed to communicate with the first flow path hole33through the flow adjusting groove42. The valve opening extent at this moment becomes an amount corresponding to a cross-section area of a portion where the flow adjusting groove42is allowed to communicate with the first flowing path hole33. Further, when the valve rod31is further rotated to reach a condition shown inFIG. 6c, the throttle valve3is brought to be a fully closed condition and the pressurized fluid is interrupted. This is because the first flow path hole33is closed by the main shaft portion31a.

Although the valve rod31is configured to be held at an arbitrary operative position by means of friction force caused by getting crushed of two of the sealing members,41and41, it may be configured to stop at a predetermined operative position by means of appropriate device other than the above.

Further, the valve rod31is preferable to be configured to contact a stopper or the like at the fully open position and the fully closed position so that the same cannot be rotated further.

An operating angle of the valve rod31from the fully open position to the fully closed position is determined according to a length in a circumferential direction of the flow adjusting groove42. Although the operating angle in the illustrated example is about 180 degrees, the same can be set to be 180 degrees or less by means of shortening a length of the flow adjusting groove42shorter than the illustrated case and vice versa.

In this case, since the flow adjusting groove42is formed such that the groove width thereof gradually narrows toward the tip end side while the groove depth gradually shallows at the same time, in comparison with that only the groove depth gradually shallows while the groove width remains constant, a variation of the valve opening extent in relation to the operating angle of the valve rod31can be set to be large and the valve opening extent is adjusted with ease.

Thus, the flow of the fluid discharged through the throttle valve3can be adjusted by means of adjusting the valve opening extent while rotating the valve rod31of the variable throttle valve3, and a moving speed of the piston13at a time when the cushioning action is created, can be controlled.

In addition, since the throttle valve3is constructed such that the flow is adjusted by means of only rotating the valve rod31around the axis line M in the valve hole30, the variable throttle valve can be constructed at a compact and simple structure with small number of parts in comparison with the conventional variable throttle valve that advances and retreats the valve rod31in the direction of the axis line M, and the variable throttle valve can be compactly assembled in the fluid pressure cylinder.

Incidentally, in the illustrated embodiment, although the piston13is configured to stop at the end of the retreating stroke in the buffered manner by means of providing the throttle valve3, the cushion chamber20, and the sealing member16at a head side (a side of the end wall10a) of the fluid pressure cylinder2, the piston13can also be configured to stop at an end of the advancing stroke in the buffered manner by means of providing these throttle valve3, the cushion chamber20, and the sealing member16at a rod side (a side of the end cover12). Alternatively, the cushioning action may be exerted to both ends of the stroke of the piston13by means of providing these throttle valve3, the cushion chamber20, and the sealing member16, at both the head side and the rod side.

In addition, in a case that the cushion chamber and the sealing member are provided at the rod side, it is sufficient to attach the cushion packing25while causing the rod insertion hole23of the end cover12to serve as the cushion chamber, and is sufficient to attach a sleeve-shaped sealing member around an outer periphery of the piston rod14.

FIG. 7shows a main part of a fluid pressure cylinder apparatus having a throttle valve in the second embodiment, and in the cylinder apparatus1B of the second embodiment, a variable throttle valve43attached to the fluid pressure cylinder2is provided with a function as a speed control valve for controlling a moving speed of the piston.

Although the throttle valve43has substantially the same construction as the throttle valve3in the first embodiment, different from the case of the first embodiment, the first flow path hole33that opens at a side face of the valve hole30is allowed to communicated with a port44, and the second flow path hole34that opens at a bottom face of the valve hole30is allowed to directly communicate with a pressure chamber45. Further, the cushion chamber and the sealing member in the first embodiment are not provided.

Incidentally, although the second flow path hole34has the same size as that of the small diameter hole portion30aof the valve hole30, the same may be smaller than the small diameter hole portion30a. Further, the port44may be located at a position indicated by a dashed line.

Since the construction of the second embodiment other than the above-described construction is the same as that of the first embodiment, the same numerals are attached to the same main portions as those in the first embodiment and explanations thereof are omitted.

In the cylinder apparatus1B of the second embodiment, a flow of the pressurized fluid supplied from the port44to the pressure chamber45, or discharged from the pressure chamber45to the port44is adjusted by means of the throttle valve43, and the piston is driven in a reciprocating movement at a speed corresponding to the adjusted flow.

The throttle valve43can be provided at both of a head side and a rod side, or can be also provided either at the head side or at the rod side.

In the throttle valves,3and43, of each of the embodiments, although the valve hole30and the valve rod31are provided with the large diameter portion and the small diameter portion, respectively, these valve hole30and the valve rod31may have a uniform diameter over an entire length thereof, as the third embodiment shown inFIG. 8. The third embodiment represents the throttle valve3that functions as a cushion valve. In the throttle valve3, the valve hole30is formed to have the uniform diameter over the entire length, and a step portion32is formed at a bottom face of the valve hole30by means of forming the second flow path hole34at the bottom face of the valve hole30at a diameter smaller than that of the valve hole30. In the valve hole30, the valve rod31formed to have the uniform diameter over the entire length is inserted, and the tip end thereof is in contact with the step portion32and hooked thereon. Thereby, the valve rod31is rotatably attached in the valve hole30. A device for hooking the valve rod31in the valve hole30is the same as that of the case in the first and second embodiments.

Incidentally, although the throttle valve3is used as a cushion valve in the first embodiment and the throttle valve43is used as a speed control valve in the second embodiment, both of the throttle valve3for the cushion and the throttle valve43for speed control can be provided in one fluid pressure cylinder2in a parallel manner.