JP6881739B2 - Multiple piston type fluid pressure cylinder - Google Patents

Description

The present invention relates to a multi-piston type fluid pressure cylinder, and more particularly to a multi-piston type fluid pressure cylinder suitable for a core cylinder for driving a core.

Since the core set in the mold is in close contact with the metal that has cooled and solidified in the mold, a large resistance acts at the start of drawing when the core is pulled out by the core cylinder, and the core is once removed from the solidified metal. After separation, it can be pulled out with a light pulling force.

Various core cylinders for driving the core as described above have been put into practical use, and Patent Document 1 discloses an example of a fluid pressure cylinder suitable for the core cylinder.

In the cylinder device with a cultivating mechanism of Patent Document 1, in order to increase the driving force up to a predetermined stroke after the piston rod starts the retracting operation, a large-diameter hole and a small-diameter hole are formed in the end wall on the rod side to form a large-diameter hole. An auxiliary piston member having a large diameter portion and a small diameter portion externally fitted to the piston rod is attached to the small diameter hole, and when the piston member of the cylinder device is driven in and out, the auxiliary piston member is also driven in and out in the same direction. , The driving force of the auxiliary piston member is applied to the piston rod until the piston rod retracts from the advance limit position by a predetermined stroke. The cylinder device also incorporates a boosting mechanism that boosts the driving force at the final stage of the operation of driving the piston rod forward.

Japanese Unexamined Patent Publication No. 2016-121788

In the cylinder device with a cultivating mechanism of Patent Document 1, a large-diameter hole and a small-diameter hole are formed in the end wall on the rod side, and an auxiliary piston member is incorporated therein. It becomes a cylinder body and its versatility is low. Moreover, since the boosting mechanism is also incorporated, the structure of the cylinder device becomes complicated.

An object of the present invention is a multi-piston type fluid pressure cylinder that can adopt a cylinder body of a fluid pressure cylinder having a general structure, and a plurality of pistons capable of increasing the driving force from the start of the piston rod to the movement of a predetermined stroke. It is to provide a type fluid pressure cylinder.

The multi-piston type hydraulic cylinder according to claim 1 is a multi-piston type in which the piston rod outputs a first driving force up to a predetermined stroke after the start of the retracting operation, and then outputs a second driving force smaller than the first driving force. A fluid pressure cylinder, a cylinder body in which a cylinder hole is formed, a main piston mounted in the cylinder hole, and a piston rod extending from the main piston and extending to the outside through a rod hole on the rod side end wall. A first sub-cylinder mechanism for strengthening the driving force is provided between the main piston and the rod side end wall in the cylinder hole, and the first sub-cylinder mechanism is from the main piston. A sub-piston having a small diameter and fixed to the piston rod, an end wall portion fitted to the piston rod so as to be liquid-tightly slidable, and a predetermined shape from the outer peripheral portion of the end wall portion to the sub-piston side. It has a floating sub-cylinder member having a sub-cylinder portion that extends in length and is liquid-tightly slidably fitted to the sub-piston, and supplies fluid pressure from the first fluid pressure supply / discharge port to the main piston. It is characterized in that it is configured to be able to receive pressure on the rod side of the sub-piston and the rod side of the sub-piston.

According to the above configuration, with the piston rod advanced to the maximum, the fluid pressure supplied from the first fluid pressure supply / exhaust port is received by the rod side of the main piston and the rod side of the sub-piston to drive in and out. Then, the driving force generated from the main piston and the driving force generated from the sub-piston are superimposed and act on the piston rod, and the enhanced first driving force is output.

When the piston rod retracts a predetermined stroke, the sub-piston of the first sub-cylinder mechanism comes into contact with the end wall portion of the sub-cylinder member, and the sub-piston, the sub-cylinder member, and the main piston start to move integrally, and the sub-cylinder Since the member is separated from the end wall on the rod side and equal fluid pressure acts on the sub-piston and the sub-cylinder member from the rod side and the anti-rod side, the piston member is driven by the fluid pressure acting on the main piston. In this way, after the piston rod retracts a predetermined stroke, the driving force of the first sub-cylinder mechanism is no longer generated, and the normal second driving force that is not enhanced is output.

Since a cylinder body similar to the cylinder body of a general hydraulic cylinder can be adopted, the versatility of the cylinder body can be maintained, and the cylinder body is incorporated between the main piston and the rod side end wall in the cylinder hole. Since the first sub-cylinder mechanism is mainly composed of a sub-piston and a sub-cylinder member, the structure is simple and can be manufactured at low cost.

In the invention of claim 1, the multi-piston type fluid pressure cylinder according to claim 2 has a main return fluid pressure chamber and a main forward fluid pressure chamber formed on the rod side and the anti-rod side of the main piston, respectively, and the sub A sub-reaction fluid pressure chamber and a sub-return fluid pressure chamber are formed on the rod side and the anti-rod side of the piston, respectively, and are communicated with the first fluid pressure supply / exhaust port and 1 or 1 or the main repulsion fluid pressure chamber. It is characterized in that a first continuous passage is formed which communicates with a plurality of the secondary repulsive fluid pressure chambers.

According to the above configuration, fluid pressure is supplied from the first fluid pressure supply / exhaust port to the main repulsive fluid pressure chamber and one or more sub-recovery fluid pressure chambers via the first continuous passage, and the piston member. Can be driven in and out, and the main repulsive fluid pressure chamber and one or more sub-recovery fluid pressure chambers can be maintained in a communicative state.

In the invention of claim 2, the multi-piston type fluid pressure cylinder according to claim 3 is configured so that fluid pressure can be supplied from the second fluid pressure supply / discharge port to the main forward fluid pressure chamber, and the main forward fluid It is characterized in that a second communication passage is formed which communicates the pressure chamber with one or more of the secondary fluid pressure chambers. According to the above configuration, the fluid pressure is supplied from the second fluid pressure supply / discharge port to the main forward fluid pressure chamber, and the fluid pressure is applied to one or more of the secondary forward fluid pressures through the second communication passage. The piston member can be advanced and driven by supplying the chamber, and the main forward fluid pressure chamber and one or more of the secondary fluid pressure chambers can be maintained in a communicative state.

The multi-piston type fluid pressure cylinder according to claim 4 is a multi-piston type fluid that outputs a third driving force until a predetermined stroke after the piston rod starts the advance operation, and then outputs a fourth driving force smaller than the third driving force. A pressure cylinder, a cylinder body having a cylinder hole formed therein, a main piston mounted in the cylinder hole, and a piston rod extending from the main piston and extending to the outside through a rod hole on the end wall on the rod side. A piston member having the piston member, an extension piston rod extending from the main piston, and at least one set of a second sub-cylinder mechanism for strengthening the driving force are provided between the main piston and the end wall on the head side, and the second sub-cylinder is provided. The mechanism consists of a sub-piston having a diameter smaller than that of the main piston and fixed to the extension piston rod, an end wall portion fitted to the extension piston rod so as to be liquid-tightly slidable, and the end wall portion. A second fluid pressure supply / discharge port having a movable sub-cylinder member having a sub-cylinder portion extending from the outer peripheral portion to the sub-piston side by a predetermined length and fitted to the sub-piston in a liquid-tight manner so as to be slidable. It is characterized in that the fluid pressure supplied from the main piston can be received on the anti-rod side of the main piston and the anti-rod side of the sub-piston.

According to the above configuration, with the piston rod retracted to the maximum, the fluid pressure supplied from the second fluid pressure supply / discharge port is received by the anti-rod side of the main piston and the anti-rod side of the sub-piston to advance. When driven, the driving force generated from the main piston and the driving force generated from the sub-piston are superimposed and act on the piston rod until a predetermined stroke after the start of the advance operation, and the enhanced third driving force is output.

After the predetermined stroke advances, the sub-piston comes into contact with the end wall portion of the sub-cylinder member, the sub-piston, the sub-cylinder member, and the main piston start to move integrally, and the sub-cylinder member separates from the head side end wall. Since the same fluid pressure acts on the sub-piston and the sub-cylinder member from the anti-rod side and the rod side, the piston rod is driven by the fluid pressure acting on the main piston. In this way, after the piston rod advances a predetermined stroke, the driving force of the second sub-cylinder mechanism is no longer generated, and the piston rod is driven by the normal fourth driving force that is not enhanced. In addition, the same effect as in claim 1 can be obtained.

In the invention of claim 1, the multi-piston type hydraulic cylinder according to claim 5 is for strengthening at least one set of a driving force and an extension piston rod extending from the piston between the main piston and the end wall on the head side. A second sub-cylinder mechanism is provided, and the second sub-cylinder mechanism is a sub-piston having a diameter smaller than that of the main piston and is fixed to the extension piston rod. A floating sub-cylinder member having an outer-fitted end wall portion and a sub-cylinder portion extending a predetermined length from the outer peripheral portion of the end wall portion toward the sub-piston side and being liquid-tightly slidably fitted to the sub-piston. It is characterized in that the fluid pressure supplied from the second fluid pressure supply / exhaust port can be received on the anti-rod side of the main piston and the anti-rod side of the sub-piston.

According to the above configuration, the increased first driving force is output while the piston rod moves in and out of the predetermined stroke, and then the second driving force that is not increased is output while the piston rod moves in and out. , While the piston rod is retracted to the maximum and the predetermined stroke advances, the enhanced third driving force is output, and then while the piston rod advances, the unenhanced fourth driving force is output. That is, the same effect as that of claims 1 and 4 can be obtained.

The present invention exhibits various effects as described above.

It is a top view of the multi-piston type hydraulic cylinder of Example 1 of this invention. It is a vertical cross-sectional view of the hydraulic cylinder (piston rod maximum advance) of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of advancing the piston rod of the hydraulic cylinder of FIG. It is a figure corresponding to FIG. 2 of the hydraulic cylinder which concerns on the 1st modification. FIG. 2 is a view corresponding to FIG. 2 of the hydraulic cylinder according to the second modified form. It is a vertical sectional view of the multi-piston type hydraulic cylinder of Example 2. FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of advancing the piston rod of the hydraulic cylinder of FIG. It is a vertical sectional view of the multi-piston type hydraulic cylinder of Example 3. FIG. It is an operation explanatory view at the time of advancing the piston rod of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of advancing the piston rod of the fluid pressure cylinder of FIG. It is an operation explanatory view at the time of advancing the piston rod of the fluid pressure cylinder of FIG. It is an operation explanatory view at the time of advancing the piston rod of the fluid pressure cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the fluid pressure cylinder of FIG. It is a vertical sectional view of the multi-piston type hydraulic cylinder of Example 4. FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of the piston rod retracting of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of advancing the piston rod of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of advancing the piston rod of the hydraulic cylinder of FIG. It is an operation explanatory view at the time of advancing the piston rod of the hydraulic cylinder of FIG.

Hereinafter, embodiments for carrying out the present invention will be described based on examples.

The multi-piston type hydraulic cylinder 1 of the first embodiment will be described with reference to FIGS. 1 to 6.
The multi-piston type hydraulic cylinder 1 is suitable for driving a core of a mold, and includes a cylinder body 2, a piston member 3, and a first sub-cylinder mechanism 4. In the following description, "hydraulic" means compressed oil (pressurized oil), not oil pressure.

The cylinder body 2 has a vertical cylinder portion 21 having a cylinder hole 20, a rod side end wall 22, a head side end wall 25, and the like, and the cylinder body 2 has a first hydraulic supply / discharge port 5 and a second. A hydraulic supply / discharge port 6 is formed. The first hydraulic supply / discharge port 5 and the second hydraulic supply / discharge port 6 are connected to the hydraulic supply source 56.

The rod-side end wall 22 is formed in a rectangular thick plate shape in a plan view, and the rod-side end wall 22 is integrally formed at the upper end of the cylinder portion 21. The rod-side end wall 22 has an end wall main body 23 and an annular member 24 that closes the upper end of the cylinder hole 20. Vertical bolt holes 23a for attaching the hydraulic cylinder 1 to an external member with four bolts are formed in the vicinity of the four corners of the end wall main body 23.

The male screw portion 24b on the upper part of the annular member 24 is screwed into the screw hole of the end wall main body 23. A rod hole 24a through which the first rod portion 31a of the piston member 3 is inserted is formed in the annular member 24, a seal member 24c is mounted on the outer peripheral portion of the annular member 24, and a seal is provided on the inner peripheral portion of the rod hole 24a. The member 24d and the dust seal 24e are attached. However, the structure of the rod side end wall 22 is not limited to the above structure. The head side end wall 25 is integrally formed at the lower end of the cylinder portion 21. A structure may be adopted in which the rod-side end wall 22 and / or the head-side end wall 25 is made of a member separate from the cylinder portion 21 and is connected to the cylinder portion 21 by a bolt or the like or a screw mechanism.

The piston member 3 has a main piston 30 mounted in the cylinder hole 20 and a piston rod 31 extending upward from the main piston 30 and extending outward through the rod hole 24a. The piston rod 31 is integrally formed with the main piston 30 and is integrally formed with the first rod portion 31a extending upward through the rod hole 24a, and is connected to the lower ends of the sub-piston 40 and the first rod portion 31a with bolts 32. It has a second rod portion 31b. A seal member 30a is attached to the outer peripheral portion of the main piston 30.

At least one set of first sub-cylinder mechanism 4 for strengthening the driving force is provided between the main piston 30 and the rod side end wall 22 in the cylinder hole 20. The first sub-cylinder mechanism 4 has a sub-piston 40 and a sub-cylinder member 41. The sub-piston 40 is formed to have a smaller diameter than the main piston 30, and the sub-piston 40 is integrally formed at the lower end portion of the first rod portion 31a. The sub-piston 40 is oil-tightly slidably mounted in the sub-cylinder hole 42 of the sub-cylinder member 41.

The sub-cylinder member 41 has an end wall portion 41a that is oil-tightly slidably fitted to the second rod portion 31b, and the sub-piston 40 extends from the outer peripheral portion of the end wall portion 41a to the sub-piston 40 side by a predetermined length. It has a sub-cylinder portion 41b that is oil-tightly slidably fitted to the outside and is movable in the vertical direction. The outer diameter of the sub-cylinder portion 41b is formed to be smaller than that of the cylinder hole 20, and the thickness of the sub-cylinder portion 41b in the radial direction is formed to be smaller according to the vertical length of the sub-cylinder portion 41b. The upper end of the sub-cylinder portion 41b can come into contact with the lower surface of the rod-side end wall 22.

The bolt 32 vertically penetrates the bolt insertion hole 32a formed in the main piston 30 and the second rod portion 31b, and the upper end side portion of the bolt 32 is screwed into the screw hole of the sub-piston 40 and the first rod portion 31a. The hexagon socket head bolt head 32b is housed in a housing hole formed in the main piston 30. A seal member 40a is attached to the outer peripheral portion of the sub-piston 40. The annular convex portion at the upper end of the second rod portion 31b is internally fitted into the concave portion at the lower end of the sub-piston 40.
The end wall portion 41a has a thickness similar to that of the sub-piston 40, and the second rod portion 31b is oil-tightly slidably inserted into the rod hole 41c formed in the end wall portion 41a, and the inside of the rod hole 41c. A seal member 41d is attached to the peripheral portion.

As shown in FIGS. 2 and 3, the main return hydraulic chamber 26a and the main forward hydraulic chamber 26b are formed on the rod side and the anti-rod side of the main piston 30 in the cylinder hole 20, respectively. In the sub-cylinder member 41, a sub-reaction hydraulic chamber 42a and a sub-forward hydraulic chamber 42b are formed on the rod side and the anti-rod side of the sub-piston 40, respectively.

A first hydraulic supply / discharge port 5 is formed on the rod side end wall 22, and communicates with the first fluid pressure supply / discharge port 5 and also communicates with the main drive hydraulic chamber 26a and the sub-reaction hydraulic chamber 42a. A single passage 50 is formed. The first communication passage 50 communicates with the annular passage 50a formed on the outer peripheral portion of the lower portion of the annular member 24 so as to be connected to the first hydraulic supply / discharge port 5, and the annular passage 50a with the sub-recovery hydraulic chamber 42a. As described above, the radial passage 50b formed in a groove shape at the lower end of the annular member 24 and the tubular passage 50c between the outer peripheral surface of the sub-cylinder member 41 and the inner peripheral surface of the cylinder hole 20 are included. In this way, the flood pressure supplied from the first hydraulic supply / discharge port 5 is supplied to the main recovery hydraulic chamber 26a and the sub-reaction hydraulic chamber 42a, and the pressure is received on the rod side of the main piston 30 and the rod side of the sub-piston 40. It is configured to be possible.

The second hydraulic supply / discharge port 6 is formed on the head side end wall 25 so as to be able to supply oil to the main forward hydraulic chamber 26b, and is a second relay that communicates the main forward hydraulic chamber 26b and the secondary forward hydraulic chamber 42b. A passage 60 is formed. The second continuous passage 60 has a through passage 60a formed vertically through the main piston 30 and the second rod portion 31b, and a radial passage 60b formed at the upper end portion of the second rod portion 31b.

Next, the operation and effect of the above-mentioned multi-piston type hydraulic cylinder 1 will be described.
When the piston member 3 is driven downward from the extended state of the piston rod shown in FIG. 2, hydraulic pressure is supplied from the first hydraulic supply / discharge port 5 and the second hydraulic supply / discharge port 6 is set to the drain pressure. The cylinder 1 operates as shown in FIGS. 2 to 6. Here, in the drawings of the present application, the oil pressure in the compressed state is displayed in gray, and the oil in the drain pressure is displayed in white.

As shown in FIGS. 2 to 4, the flood pressure supplied from the first hydraulic supply / discharge port 5 is filled in the main drive hydraulic chamber 26a and the sub-reaction hydraulic chamber 42a, and is filled with the main forward hydraulic chamber 26b and the secondary forward. The hydraulic and hydraulic chamber 42b has a drain pressure. Therefore, the main piston 30 and the sub-piston 40 receive the hydraulic pressure on the rod side, and the piston member 3 is driven downward. At this time, since the driving force of the sub-piston 40 is also output in addition to the driving force of the main piston 30, the piston member 3 outputs a large first driving force. If the driving force due to the hydraulic pressure acting on the rod side of the main piston 30 is P and the driving force due to the hydraulic pressure on the rod side of the sub-piston 40 is Q (however, Q <P), the first driving force = (P + Q). Is.

After that, as shown in FIG. 4, when the sub-piston 40 descends to the maximum in the sub-cylinder hole 42 and the sub-piston 40 comes into contact with the end wall portion 41a of the sub-cylinder member 41, the sub-forward hydraulic chamber 42b disappears. .. When the piston member 3 is further lowered from that state, the upper end of the sub-cylinder member 41 is separated from the rod side end wall 22, and as shown in FIG. 5, equal hydraulic pressure acts on both the upper and lower surfaces of the sub-cylinder member 41 and the sub-piston 40. Therefore, the sub-piston 40 does not generate a downward driving force, and the piston member 3 is driven downward only by the second driving force output from the main piston 30. This second driving force is the second driving force = P.

That is, the hydraulic cylinder 1 outputs a first driving force until the piston rod 31 descends by a predetermined stroke S shown in FIG. 2, and then outputs a second driving force smaller than the first driving force. The predetermined stroke S is equal to the maximum stroke of the sub-piston 40 in the sub-cylinder hole 42. Therefore, when the core is separated from the weld metal, the piston member 3 can be driven by a large first driving force, and thereafter, the piston member 3 can be driven by a second driving force smaller than the first driving force. ..

Next, when the piston member 3 is advanced and driven from the retracted state shown in FIG. 6, the first hydraulic supply / discharge pump 5 is set to the drain pressure, the flood control is supplied to the second hydraulic supply / discharge port 6, and the main forward movement is performed. The flood control is supplied to the hydraulic chamber 26b and the secondary forward hydraulic chamber 42b.

Then, as shown in FIG. 7, the sub-cylinder member 41 descends and comes into contact with the main piston 30, and while maintaining the contact state, the piston member 3 including the main piston 30, the sub-piston 40, and the sub-cylinder member 41 Is driven upward to reach the state shown in FIG. The rising driving force in this case is approximately equal to the hydraulic pressure acting on the lower surface of the main piston 30.

In this hydraulic cylinder 1, since the cylinder body 2 similar to the cylinder body of a general hydraulic cylinder can be adopted, the versatility of the cylinder body 2 can be maintained, and the main piston 30 and the main piston 30 are formed in the cylinder hole 20. Since the first sub-cylinder mechanism 4 incorporated between the rod-side end walls 22 is mainly composed of the sub-piston 40 and the sub-cylinder member 41, the structure is simple and can be manufactured at low cost.

The piston member 3 can be moved in and out by supplying oil from the first hydraulic supply / discharge port 5 to the main drive hydraulic chamber 26a and the sub-reaction hydraulic chamber 42a via the first continuous passage 50, and the main drive hydraulic chamber can be driven back and forth. The 26a and the sub-recovery hydraulic chamber 42a can be maintained in a communicative state.

Supplying oil pressure from the second hydraulic supply / discharge port 6 to the main forward hydraulic chamber 26b, and supplying the hydraulic pressure to the secondary forward hydraulic chamber 42b via the second continuous passage 60 to advance drive the piston member 3. The main flood control chamber 42b and the secondary flood control chamber 42b can be kept in a communicative state.

Here, an example of partially modifying the above embodiment will be described.
1) The second connecting passage 60 is formed on the outer peripheral side of the bolt 32 in the upper half of the second rod portion 31b, and the main piston 30 communicates the annular passage with the main forward hydraulic chamber 26b. It may also be composed of an inclined passage formed in the second rod portion 31b.

2) In the multi-piston type hydraulic cylinder 1A shown in FIG. 8, the piston member 3A is provided with a piston rod 31A in which the first rod portion 31a and the second rod portion 31b are integrated, and the sub-piston 40A is the above-mentioned piston. It may be formed integrally with the rod 31A.

A shaft portion 31c to be fitted into the shaft hole 30b at the center of the main piston 30A is formed at the lower end portion of the piston rod 31A, and a screw shaft is formed at the lower half portion of the shaft portion 31c. The main piston 30 is connected to the piston rod 31A by screwing the nut 31d. The second communication passage 60A is composed of a vertical passage 60c formed in the lower part of the piston rod 31A and an inclined passage 60d that communicates the upper end of the vertical passage 60c with the sub-forward hydraulic chamber 42b.

3) In the multi-piston type hydraulic cylinder 1B shown in FIG. 9, in the same structure as in FIG. 8, the screw shaft in the lower half of the shaft portion 31c is omitted, and the main piston 30B is a piston using the retaining ring 31e. It is connected to the piston rod 31B of the member 3B.

The multi-piston type hydraulic cylinder 1C according to the second embodiment will be described with reference to FIGS. 10 to 15. However, the same members as in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.
As shown in FIGS. 10 and 11, in the hydraulic cylinder 1C, two sets of first sub-cylinder mechanisms 4C and 4D are provided between the main piston 30 and the rod side end wall 22 in the cylinder hole 20. ing.

The hydraulic cylinder 1C has a first sub-cylinder mechanism 4C and a first sub-cylinder mechanism 4D. The first sub-cylinder mechanism 4C has a sub-piston 40c and a sub-cylinder member 41C, and the first sub-cylinder mechanism 4D has a sub-piston 40d and a sub-cylinder member 41D. The sub-pistons 40c and 40d and the sub-cylinder members 41C and 41D are the same as those in the first embodiment.

The piston rod 31C of the piston member 3C of the hydraulic cylinder 1C is composed of a first rod portion 31c, a second rod portion 31d, and a third rod portion 31e. The bolt 32 is inserted into the bolt insertion holes 32c formed in the second and third rod portions 31d and 31e, and the upper end portion of the bolt 32 is screwed into the screw hole formed in the lower end portion of the first rod 31c. The first to third rod portions 31c to 31e are integrally connected.

Similar to the sub-cylinder member 41 of the first embodiment, the sub-cylinder member 41C has an end wall portion 43a, a sub-cylinder portion 43b, and a sub-cylinder hole 43c, and the sub-cylinder member 41D has an end wall portion 44a and a sub-cylinder portion. It has 44b and an auxiliary cylinder hole 44c. The end wall portion 43a of the sub-cylinder member 41C is fitted on the second rod portion 31d so as to be oil-tightly slidable, and the sub-piston 40c is mounted on the sub-cylinder hole 43c of the sub-cylinder member 41C so as to be oil-tightly slidable. .. The end wall portion 44a of the sub-cylinder member 41D is fitted onto the third rod portion 31e so as to be oil-tightly slidable, and the sub-piston 40d is mounted in the sub-cylinder hole 44c of the sub-cylinder member 41D so as to be oil-tightly slidable. ..

The main recovery hydraulic chamber 26a and the main forward hydraulic chamber 26b are formed on the rod side and the anti-rod side of the main piston 30, respectively, and the sub-reaction hydraulic chambers 42c and 42e are formed on the rod side of the sub-pistons 40c and 40d, respectively. , Sub-rotation hydraulic chambers 42d, 42f are formed on the opposite rod side of the sub-pistons 40c, 40d.

A first communication passage 50C that communicates with the first hydraulic supply / discharge port 5 is formed, and a first communication passage 50C that connects the main recovery hydraulic chamber 26a and the two sub-reaction hydraulic chambers 42c and 42e is formed. There is.
The first continuous passage 50C includes an annular passage 50a on the outer peripheral side of the lower portion of the annular member 24, a radial passage 50b formed in a groove shape at the lower end of the annular member 24, and outer peripheral surfaces of the auxiliary cylinder members 41C and 41D. It is composed of an annular passage 50c between the cylinder hole 20 and the inner peripheral surface of the cylinder hole 20, and radial passages 50d and 50e formed in a groove shape at the lower ends of the end wall portions 43a and 44a of the auxiliary cylinder members 41C and 41D. ing.

A second communication passage 60C is formed in which the main flood control chamber 26b communicates with the sub-communication flood control chambers 42d and 42f. The second continuous passage 60C penetrates through the through passage 60c formed in a penetrating shape in the second rod portion 31d, the radial passage 60d formed in the upper end portion of the second rod portion 31d, and the third rod portion 31e. It has a through passage 60e formed in a shape and a radial passage 60f formed at the upper end of the third rod portion 31e.

Next, the action and effect of the hydraulic cylinder 1C will be described.
As shown in FIG. 10, when the second hydraulic supply / discharge port 6 is held at the drain pressure and the oil supply is supplied to the first hydraulic supply / discharge port 5 from the extended state in which the piston rod 31C is extended, FIG. As shown in FIG. 12, the main recovery hydraulic chamber 26a and the sub-reaction hydraulic chambers 42c and 42e expand until the piston rod 31C descends by a predetermined stroke. The predetermined stroke is the same as the predetermined stroke S of the first embodiment.

At this time, the piston rod 31C is driven downward with a large first driving force because the hydraulic pressure is received by the rod side of the main piston 30 and the rod side of the sub-pistons 40c and 40d. If the driving force acting on the rod side of the main piston 30 is P and the driving force acting on the rod side of one of the sub-pistons 40c and 40d is Q (however, Q <P), the first driving force = ( P + 2Q).

After that, when the piston rod 31C is lowered even a little from the state of FIG. 12, the sub-cylinder member 41C is separated from the rod side end wall 22 as shown in FIGS. 13 and 14, and the sub-pistons 40c and 40d and the sub-cylinder member 41C are separated from each other. In 41D, since equal hydraulic pressure acts on both the upper and lower surfaces, the sub-pistons 40c and 40d do not generate a driving force, and the piston rod 31C is driven downward by the hydraulic pressure (second driving force) acting on the main piston 30. .. This second driving force is the second driving force = P. FIG. 14 shows a state in which the piston rod 31C is lowered to the maximum.

When the piston rod 31C is driven upward from the state shown in FIG. 14, the first hydraulic supply / discharge port 5 is used as the drain pressure, and the flood control is supplied to the second hydraulic supply / discharge port 6.
Then, as shown in FIG. 15, the auxiliary cylinder members 41C and 41D are lowered to bring the auxiliary oil chambers 42d and 42f to the maximum expanded state, and the piston member including the main piston 30 is maintained in that state. The 3C, the sub-pistons 40c and 40d, and the sub-cylinder members 41C and 41D are driven ascending to reach the state shown in FIG. The rising driving force in this case is mainly the oil pressure acting on the sub-piston 40c and the oil pressure acting on the central side portion and the outer peripheral portion of the main piston 30, but this hydraulic pressure is applied to the lower surface of the main piston 30. The magnitude is almost equal to the acting oil pressure.

According to the hydraulic cylinder 1C of the second embodiment, the piston rod 31C can be driven downward with a remarkably large first driving force at the initial stage (up to a predetermined stroke) when the piston rod 31C is retracted and driven as described above. .. In addition, the same effect as that of the hydraulic cylinder 1 of the first embodiment can be obtained.

The multi-piston type hydraulic cylinder according to the third embodiment will be described with reference to FIGS. 16 to 21. However, the same members as in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.
This hydraulic cylinder 1D is a multi-piston type hydraulic cylinder in which the piston rod 31D of the piston member 3D outputs a third driving force up to a predetermined stroke after the start of the advance operation, and then outputs a fourth driving force smaller than the third driving force. Is.

The hydraulic cylinder 1D includes a cylinder body 2 in which a cylinder hole 20 is formed and a piston member 3D, and the piston member 3D includes a main piston 30 mounted in the cylinder hole 20 and a rod side extending from the main piston 30. It has a piston rod 31D that extends outward through the rod hole 24a of the end wall 22. Between the main piston 30 and the head side end wall 25, an extension piston rod 31f extending from the main piston 30 toward the head side end wall 25 and at least one set of a second sub-cylinder mechanism 4E for strengthening the driving force are provided. ing.

The second sub-cylinder mechanism 4E includes a sub-piston 40e having a diameter smaller than that of the main piston 30 and fixed to the tip of the extension piston rod 31f, and a sub-cylinder member 41E that can move in the vertical direction. ..
The sub-cylinder member 41E has an end wall portion 45a that is oil-tightly slidably fitted to the extension piston rod 31f, and extends from the outer peripheral portion of the end wall portion 45a to the sub-piston 40e side by a predetermined length to the sub-piston 40e. It has a sub-cylinder portion 45b that is oil-tightly slidably fitted, and a sub-cylinder hole 45c. The outer diameter of the sub-cylinder portion 45b is smaller than the inner diameter of the cylinder hole 20.

A shaft portion 31c is formed at the lower end portion of the extension piston rod 31f, the shaft portion 31c is fitted into a shaft hole at the center of the sub-piston 40e, and the sub-piston 40e is connected to the shaft portion 31c by a retaining ring 31e. The main return hydraulic chamber 26a and the main forward hydraulic chamber 26b are formed on the rod side and the anti-rod side of the main piston 30, respectively. In the sub-cylinder portion 45b, a sub-reaction hydraulic chamber 42g and a sub-forward hydraulic chamber 42h are formed on the rod side and the anti-rod side of the sub-piston 40e, respectively.

In order to make it possible to supply oil from the first hydraulic supply / discharge port 5 to the main recovery hydraulic chamber 26a and the sub-reaction hydraulic chamber 42g, the annular passage 50a on the outer peripheral side of the lower portion of the annular member 24 and the lower surface of the annular member 24. A groove-shaped radial passage 50b is formed in the main piston 30, the piston rod 31D, and the extension piston rod 31f are formed with a communication passage 50g for communicating the main recovery hydraulic chamber 26a and the sub-reaction hydraulic chamber 42g. The flood control can be supplied from the second hydraulic supply / discharge port 6 to the main forward hydraulic chamber 26b.

The operation and effect of this hydraulic cylinder 1D will be described.
As shown in FIG. 16, when the piston rod 31D is extended from the state where the piston rod 31D retracts and the sub-cylinder member 41E is in contact with the head side end wall 25, the first hydraulic supply / discharge port 5 is opened. It is held at the drain pressure and oil is supplied from the second hydraulic supply / discharge port 6 to the main forward hydraulic chamber 26b and the secondary forward hydraulic chamber 42h to the anti-rod side of the main piston 30 and the anti-rod side of the sub-piston 40e. Receive pressure.

Then, as shown in FIGS. 16 to 18, the main forward-moving hydraulic chamber 26b and the secondary forward-moving hydraulic chamber 42h expand until the piston rod 31D rises by a predetermined stroke (until the state shown in FIG. 18 is reached). Outputs the third driving force. In this case, let F be the driving force of the main piston 30 (assuming that the pressure is received on the entire lower surface of the circle), and let G (provided that G <F) be the driving force of the sub-piston 40e (assuming that the pressure is received on the annular portion). , The third driving force is the third driving force = (F + G).

After that, when the piston rod 31D rises even a little from the state where the sub-forwarding hydraulic chamber 42h is expanded to the maximum as shown in FIG. 18, the sub-cylinder member 41E is separated from the head side end wall 25 and is in the state as shown in FIG. And the fourth driving force is output. At this time, since the same driving force acts on both the upper and lower surfaces of the auxiliary cylinder member 41E and the auxiliary piston 40e on the outer diameter side of the extension piston rod 31f, the driving force G is not generated and the driving force F Only output.

That is, the fourth driving force at this time is equal to the oil pressure acting on the entire lower surface of the circle on the opposite rod side of the main piston 30. This fourth driving force is the fourth driving force = F.
In this way, when the piston rod 31D rises, a large third driving force is output from the start of the rise until the predetermined stroke rises, and after the predetermined stroke rises, a fourth driving force of a normal magnitude is output.

When the piston rod 31D is driven in and out from the state of FIG. 20, the second hydraulic supply / discharge port 6 is switched to the drain pressure, and the oil supply is supplied to the first hydraulic supply / discharge port 5, as shown in FIG. In addition, the sub-recovery hydraulic chamber 42g is expanded to the maximum extent, the sub-cylinder member 41E is in contact with the main piston 30, and the piston member 3D is lowered while maintaining that state, and the state shown in FIG. 16 is reached. Become. Other than that, it has the same operation and effect as the hydraulic cylinder of the first embodiment.

The multi-piston type hydraulic cylinder 1E according to the fourth embodiment will be described with reference to FIGS. 22 to 29. However, the same members as those in Examples 1 and 3 are designated by the same reference numerals, and the description thereof will be omitted. Since this hydraulic cylinder 1E incorporates the first sub-cylinder mechanism 4 of the first embodiment and the second sub-cylinder mechanism 4E of the third embodiment, the first sub-cylinder mechanism 4 and the second sub-cylinder mechanism 4E are incorporated. Similar members are designated by the same reference numerals and the description thereof will be omitted.

The piston rod 31E of the piston member 3E is a first rod portion 31g, a second rod portion 31h extending below the first rod portion 31g, and a second rod portion 31h connected to the first rod portion 31g by screwing. The main piston 30 is integrally formed at the lower end of the second rod portion 31h, and the main piston 30 is mounted in the cylinder hole 20.

At least one set of first sub-cylinder mechanism 4 is mounted between the main piston 30 and the rod side end wall 22. Between the main piston 30 and the head side end wall 25, an extension piston rod 31i extending downward from the main piston 30 and at least one set of second sub-cylinder mechanisms 4E are provided.

When the piston rod 31E moves in and out, the multi-piston type hydraulic cylinder 1E outputs a strengthened first driving force from the start of moving in and out to a predetermined stroke, and then in FIG. 25. , As shown in FIG. 26, outputs an unreinforced second driving force.
When the piston rod 31E is extended, as shown in FIGS. 27 and 28, an enhanced third driving force is output from the start of extension to a predetermined stroke, and then an unenhanced fourth driving force is output as shown in FIG. 29. To do. Other than that, it has the same actions and effects as those of Examples 1 and 3.

Next, an example of partially modifying the above embodiment will be described.
1) In Examples 1 to 4, the case where the present invention is applied to a multi-piston type hydraulic cylinder in which the "fluid pressure" is "flood control" has been described as an example, but the "fluid pressure" is "pressurized air". The present invention can also be applied to a multi-piston type air cylinder.

2) The length of the cylinder body of Examples 1 to 4 is merely an example, and the length of the cylinder body can be freely set. Further, the main piston and / or the sub-piston need not be formed integrally with the piston rod, and may be formed separately from the piston rod and connected to the piston rod by various connecting means.

3) The tubular passage between the outer peripheral surface of the sub-cylinder portion and the inner peripheral surface of the cylinder hole may be eliminated, and one or more vertical groove-shaped passages may be formed in place of the tubular passage.

4) In the multi-piston type fluid pressure cylinder of the present invention, it is also possible to incorporate three or more sets of first sub-cylinder mechanisms. Further, in the multi-piston type fluid pressure cylinder of the present invention, it is possible to incorporate two or more sets of second sub-cylinder mechanisms.

5) The multi-piston type fluid pressure cylinder of the present invention can be applied to various applications other than the core cylinder for driving the core.
6) In addition, a person skilled in the art can carry out the embodiment by adding various modifications to the above embodiment without departing from the spirit of the present invention, and the present invention also includes such modified forms.

1,1C, 1D Multiple piston type hydraulic cylinder 2 Cylinder body 3,3C, 3D, 3E Piston members 4, 4C, 4D 1st sub-cylinder mechanism 4E 2nd sub-cylinder mechanism 5 1st hydraulic air supply / discharge port 6 2nd Hydraulic supply / discharge port 20 Cylinder hole 22 Rod side end wall 24a Rod hole 25 Head side end wall 26a Main return hydraulic chamber 26b Main forward hydraulic chamber 30 Main piston 31, 31C, 31D, 31E Piston rod 31f, 31i Extension piston rod 40, 40c, 40d, 40e Sub-piston 41, 41C, 41D, 41E Sub-cylinder members 41a, 43a, 44a, 45a End wall portions 41b, 43b, 44b, 45b Sub-cylinder portions 42c, 42e Sub-flow hydraulic chamber 50, 50C 1st passage 60, 60C 2nd passage

Claims (5)

A multi-piston type fluid pressure cylinder in which the piston rod outputs a first driving force up to a predetermined stroke after the start of the retracting operation, and then outputs a second driving force smaller than the first driving force.
Cylinder body with cylinder holes and
A piston member having a main piston mounted in the cylinder hole and a piston rod extending from the main piston and extending to the outside through a rod hole on the end wall on the rod side.
At least one set of first sub-cylinder mechanism for strengthening the driving force is provided between the main piston and the rod side end wall in the cylinder hole.
The first sub-cylinder mechanism is
A sub-piston having a diameter smaller than that of the main piston and fixed to the piston rod, an end wall portion fitted to the piston rod so as to be liquid-tightly slidable, and a sub-piston from the outer peripheral portion of the end wall portion. It has a movable sub-cylinder member having a sub-cylinder portion that extends to the piston side by a predetermined length and is liquid-tightly slidably fitted to the sub-piston.
A multi-piston type fluid pressure cylinder characterized in that the fluid pressure supplied from the first fluid pressure supply / exhaust port can be received on the rod side of the main piston and the rod side of the sub-piston. A main revolving fluid pressure chamber and a main revolving fluid pressure chamber are formed on the rod side and the anti-rod side of the main piston, respectively.
A sub-reaction fluid pressure chamber and a sub-forward fluid pressure chamber are formed on the rod side and the anti-rod side of the sub-piston, respectively.
A claim characterized in that a first communication passage is formed that communicates with the first fluid pressure supply / exhaust port and also communicates with the main repulsive fluid pressure chamber and one or a plurality of the sub remotive fluid pressure chambers. Item 2. The plurality of piston type fluid pressure cylinders according to Item 1. The fluid pressure can be supplied from the second fluid pressure supply / exhaust port to the main forward fluid pressure chamber.
The plurality of piston type fluid pressure cylinders according to claim 2, wherein a second communication passage communicating the main forward fluid pressure chamber and one or a plurality of the auxiliary forward fluid pressure chambers is formed. A multi-piston type fluid pressure cylinder that outputs a third driving force until a predetermined stroke after the piston rod starts the advance operation, and then outputs a fourth driving force smaller than the third driving force.
Cylinder body with cylinder holes and
A piston member having a main piston mounted in the cylinder hole and a piston rod extending from the main piston and extending to the outside through a rod hole on the end wall on the rod side.
An extension piston rod extending from the main piston and at least one set of a second sub-cylinder mechanism for strengthening the driving force are provided between the main piston and the end wall on the head side.
The second sub-cylinder mechanism is
From the sub-piston having a diameter smaller than that of the main piston and fixed to the extension piston rod, the end wall portion fitted to the extension piston rod so as to be liquid-tightly slidable, and the outer peripheral portion of the end wall portion. It has a movable sub-cylinder member having a sub-cylinder portion that extends to the sub-piston side by a predetermined length and is liquid-tightly slidably fitted to the sub-piston.
A multi-piston type fluid pressure cylinder characterized in that the fluid pressure supplied from the second fluid pressure supply / exhaust port can be received on the anti-rod side of the main piston and the anti-rod side of the sub-piston. An extension piston rod extending from the piston and at least one set of a second sub-cylinder mechanism for strengthening the driving force are provided between the main piston and the end wall on the head side.
The second sub-cylinder mechanism is
From the sub-piston having a diameter smaller than that of the main piston and fixed to the extension piston rod, the end wall portion fitted to the extension piston rod so as to be liquid-tightly slidable, and the outer peripheral portion of the end wall portion. It has a movable sub-cylinder member having a sub-cylinder portion that extends to the sub-piston side by a predetermined length and is liquid-tightly slidably fitted to the sub-piston.
The multi-piston type fluid pressure cylinder according to claim 1, wherein the fluid pressure supplied from the second fluid pressure supply / exhaust port can be received on the anti-rod side of the main piston and the anti-rod side of the sub-piston. ..

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