JP2021143704A - Fluid pressure cylinder - Google Patents

Abstract

To provide a fluid pressure cylinder stably actuated.SOLUTION: A fluid pressure cylinder 100 includes a cylinder tube 10, a piston portion 20 that is slidably inserted in the cylinder tube 10 and divides a rod side chamber 1 and an opposite rod side chamber 5 in the cylinder tube 10, a rod member 60 that is inserted in the cylinder tube 10 and is coupled to the piston portion 20 at a tip end portion, and a pipe member 70 that is provided in the rod member 60 and leads a working fluid to the rod side chamber 1 and the opposite rod side chamber 5. The pipe member 70 has a first pipe portion 71 that is joined with a tip end side of the piston portion 20 or the rod member 60, a second pipe portion 72 supported on a base end side of the rod member 60, and a displacement portion 73 that couples the first pipe portion 71 and the second pipe portion 72 and permits the relative displacement of the first pipe portion 71 and the second pipe portion 72.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fluid pressure cylinder.

Patent Document 1 describes rod side chambers and anti-rod side chambers formed on both sides of a piston slidably inserted into a cylinder tube, and one end fixed to the piston and the other end penetrating the end lid of the cylinder tube. A fluid pressure cylinder having a protruding hollow piston rod and a pipe member locked between the mounting member pivotally attached to the protruding end of the piston rod and the piston and inserted into the hollow piston rod. Is disclosed. Two outflow ports are formed in the mounting member, one communicating with the anti-rod side chamber through the pipe member and the other communicating with the rod side chamber through the hollow piston rod and between the pipe member. The piston rod and the pipe member are fixed to the piston by welding.

Jitsukaisho 48-77593

In the fluid pressure cylinder described in Patent Document 1, stress is generated at the joint portion between the piston and the pipe member due to the load acting on the piston due to the pressure of the working fluid. If an unexpectedly large stress acts on the joint between the piston and the pipe member for a long period of time, the rod side chamber and the anti-rod side chamber communicate with each other through the joint, which may affect the operation of the fluid pressure cylinder.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a fluid pressure cylinder that operates stably.

The present invention is a fluid pressure cylinder, which is a fluid pressure cylinder, a cylinder tube, a piston portion slidably inserted into the cylinder tube to partition a rod side chamber and an anti-rod side chamber in the cylinder tube, and a piston portion inserted into the cylinder tube and the tip side is a piston portion. A rod member connected to the rod member and a pipe member provided in the rod member to guide a working fluid to the rod side chamber or the anti-rod side chamber, and the pipe member is joined to the piston portion or the tip end side of the rod member. Displacement that connects the pipe portion, the second pipe portion supported on the base end side of the rod member, the first pipe portion and the second pipe portion, and allows relative displacement between the first pipe portion and the second pipe portion. It is characterized by having a part and.

In the present invention, the displacement of the displaced portion of the pipe member reduces the stress generated at the joint portion of the pipe member with respect to the piston portion or the rod member. Therefore, it is prevented that the rod side chamber and the anti-rod side chamber communicate with each other through the joint portion, and the operation of the fluid pressure cylinder is stabilized.

The present invention is characterized in that the displacement portion has a cylindrical elastic member.

The present invention is characterized in that the displacement portion has a coil portion having a hollow portion through which a working fluid can pass.

The present invention is characterized in that the displacement portion is formed by overlapping the end portion of the first pipe portion and the end portion of the second pipe portion so as to be slidable in the axial direction.

In these inventions, the displacement portion can reduce the stress generated at the joint portion of the pipe member with respect to the piston portion or the rod member.

According to the present invention, it is possible to provide a fluid pressure cylinder that operates stably.

It is sectional drawing of the fluid pressure cylinder which concerns on embodiment of this invention, and is the figure which shows the maximum contraction state. It is sectional drawing of a rod member, a third piston, and a pipe member. It is sectional drawing which shows the fluid pressure cylinder which concerns on embodiment of this invention, and is the figure which shows the state which the 1st piston is at the extension stroke end, and the 2nd piston and the 3rd piston are at a contraction stroke end. It is sectional drawing which shows the fluid pressure cylinder which concerns on embodiment of this invention, and shows the state which the 1st piston and the 2nd piston are at the extension stroke end, and the 3rd piston is at a contraction stroke end. It is sectional drawing which shows the fluid pressure cylinder which concerns on embodiment of this invention, and is the figure which shows the most extended state. It is sectional drawing of the rod member, the third piston, and the pipe member which shows an example of the joint part of a pipe member. It is sectional drawing of the pipe member which concerns on the modification of embodiment of this invention. It is sectional drawing of the pipe member which concerns on the modification of embodiment of this invention.

Hereinafter, the fluid pressure cylinder according to the embodiment of the present invention will be described with reference to the drawings. Hereinafter, a case where the hydraulic cylinder is a multi-stage hydraulic cylinder 100 (hereinafter, simply referred to as “hydraulic cylinder 100”) that drives hydraulic oil as a hydraulic fluid will be described.

As shown in FIG. 1, the hydraulic cylinder 100 has a bottomed cylinder-shaped cylinder tube 10 and a piston portion that is slidably inserted into the cylinder tube 10 to partition a rod side chamber 1 and an anti-rod side chamber 5 into the cylinder tube 10. 20 and a rod member 60 that is inserted into the cylinder tube 10 and whose tip end side is connected to the piston portion 20. The hydraulic cylinder 100 is attached to the device to be driven via the first attachment portion 65 provided at the bottom of the cylinder tube 10 and the second attachment portion 62 of the rod member 60. In the present embodiment, the hydraulic cylinder 100 is attached to the device to be driven so that the cylinder tube 10 is on the vertical upper side and the rod member 60 is on the vertical lower side (direction shown in FIG. 1), and the hydraulic cylinder 100 expands and contracts. (Ii) A case where the first mounting portion 65 moves up and down with respect to the mounting portion 62 will be described.

The piston portion 20 slides the first piston 30 that slides on the inner peripheral surface of the cylinder tube 10, the second piston 40 that slides on the inner peripheral surface of the first piston 30, and the inner peripheral surface of the second piston 40. It has a third piston 50 to which a moving rod member 60 is connected. A cylinder head 11 that slidably supports the first piston 30 of the piston portion 20 is provided in the opening of the cylinder tube 10.

The rod side chamber 1 has a first rod side chamber 2, a second rod side chamber 3, and a third rod side chamber 4. The first rod side chamber 2 is partitioned by a cylinder tube 10, a cylinder head 11, and a first piston 30. The second rod side chamber 3 is partitioned by the first piston 30 and the second piston 40. The third rod side chamber 4 is partitioned by a second piston 40, a third piston 50, and a rod member 60.

The anti-rod side chamber 5 is partitioned by a cylinder tube 10, a piston portion 20, and a rod member 60. In this way, the rod side chamber 1 and the anti-rod side chamber 5 are partitioned in the cylinder tube 10.

A seal member (not shown) is provided on the inner peripheral surface of the cylinder head 11 to seal a gap between the inner peripheral surface of the first piston 30 and the outer peripheral surface of the first piston 30. A first extension side port 11A that opens into the first rod side chamber 2 is formed on the inner peripheral surface of the cylinder head 11.

A recess 10A that opens into the anti-rod side chamber 5 is formed at the bottom of the cylinder tube 10. The recess 10A is formed to have an inner diameter larger than the inner diameter of the first piston 30. As a result, the pressure of the hydraulic oil guided to the recess 10A acts on the first piston 30.

The first piston 30 has a cylindrical first main body 31 and a cylindrical first sliding contact formed so as to project radially outward from one end of the first main body 31 and slidably contact the inner peripheral surface of the cylinder tube 10. A portion 32, a cylindrical first support portion 33 formed so as to project radially inward from the other end of the first main body portion 31 and slidably support the second piston 40, and a first sliding contact portion 32. It has a first piston ring 34 provided on the outer peripheral surface.

In the first main body portion 31, a first series through port 30A penetrating in the radial direction is formed at a position adjacent to the first sliding contact portion 32. The first rod side chamber 2 communicates with the second rod side chamber 3 through the first communication port 30A in a state where the second piston 40 is in the most contracted position.

The first sliding contact portion 32 slides between the bottom portion of the cylinder tube 10 and the cylinder head 11. The maximum contraction position of the first piston 30 is defined when the first sliding contact portion 32 abuts on the bottom of the cylinder tube 10, and the maximum extension position is defined when the first sliding contact portion 32 abuts on the cylinder head 11.

A second extension side port 33A that opens into the second rod side chamber 3 is formed on the inner peripheral surface of the first support portion 33. Further, a seal member (not shown) is provided on the inner peripheral surface of the first support portion 33 to close the gap between the first support portion 33 and the outer peripheral surface of the second piston 40.

The first piston ring 34 is a metal annular member. The first piston ring 34 blocks communication between the first rod side chamber 2 and the anti-rod side chamber 5 through a gap between the outer peripheral surface of the first sliding contact portion 32 and the inner peripheral surface of the cylinder tube 10.

Further, a bush (not shown) that is in sliding contact with the inner peripheral surface of the cylinder tube 10 is provided on the outer peripheral surface of the first sliding contact portion 32. The first piston 30 is slidably supported by the cylinder tube 10 by the bush sliding in contact with the inner peripheral surface of the cylinder tube 10.

A first snap ring 25 that can be engaged with the second piston 40 is mounted in the annular groove on the inner peripheral surface of the first sliding contact portion 32. The first snap ring 25 regulates the first piston 30 from falling off from the second piston 40.

The second piston 40 has the same configuration as the first piston 30. Specifically, as shown in FIG. 1, the second piston 40 is formed of a cylindrical second main body 41 and one end of the second main body 41 protruding outward in the radial direction of the first piston 30. A cylindrical second sliding contact portion 42 that is in sliding contact with the inner peripheral surface, and a cylindrical second portion that is formed so as to project radially inward from the other end of the second main body portion 41 and slidably supports the rod member 60. It has a support portion 43 and a second piston ring 44 provided on the outer peripheral surface of the second sliding contact portion 42.

A second communication port 40A penetrating in the radial direction is formed in the second main body 41 at a position adjacent to the second sliding contact portion 42. The second rod side chamber 3 communicates with the third rod side chamber 4 through the second communication port 40A in a state where the third piston 50 is in the most contracted position.

The second sliding contact portion 42 slides between the first snap ring 25 of the first piston 30 and the first support portion 33. The maximum contraction position of the second piston 40 is defined when the second sliding contact portion 42 abuts on the first snap ring 25, and the maximum extension position is defined when the second sliding contact portion 42 abuts on the first support portion 33.

A third rod side port 43A that opens into the third rod side chamber 4 is formed on the inner peripheral surface of the second support portion 43. Further, a seal member (not shown) is provided on the inner peripheral surface of the second support portion 43 to close the gap between the rod member 60 and the outer peripheral surface.

The second piston ring 44 is a metal annular member like the first piston ring 34. The second piston ring 44 counteracts the second rod side chamber 3 through the gap between the outer peripheral surface of the second sliding contact portion 42 of the second piston 40 and the inner peripheral surface of the first main body portion 31 of the first piston 30. Communication with the rod side chamber 5 is cut off.

A bush (not shown) that is in sliding contact with the inner peripheral surface of the first piston 30 is provided on the outer peripheral surface of the second sliding contact portion 42. The second piston 40 is slidably supported by the first piston 30 by the bush sliding in contact with the inner peripheral surface of the first piston 30.

A second snap ring 26 that can be engaged with the third piston 50 is mounted in the annular groove on the inner peripheral surface of the second sliding contact portion 42. The second snap ring 26 regulates the removal of the second piston 40 from the third piston 50.

The third piston 50 is formed of a cylindrical third sliding contact portion 51 that is in sliding contact with the inner peripheral surface of the second piston 40 and a rod member 60 that projects radially from the inner peripheral surface of the third sliding contact portion 51. It has an annular connecting portion 52 connected to the tip portion and a third piston ring 54 provided on the outer peripheral surface of the third sliding contact portion 51.

The third sliding contact portion 51 slides between the second snap ring 26 of the second piston 40 and the second support portion 43. The maximum contraction position of the third piston 50 is defined when the third sliding contact portion 51 abuts on the second snap ring 26, and the maximum extension position is defined when the third sliding contact portion 51 abuts on the second support portion 43.

The third piston ring 54 is a metal annular member like the first and second piston rings 34 and 44. The third piston ring 54 opposes the third rod side chamber 4 through the gap between the outer peripheral surface of the third sliding contact portion 51 of the third piston 50 and the inner peripheral surface of the second main body portion 41 of the second piston 40. Communication with the rod side chamber 5 is cut off.

Further, a bush (not shown) that is in sliding contact with the inner peripheral surface of the second piston 40 is provided on the outer peripheral surface of the third sliding contact portion 51. When the bush slides into contact with the inner peripheral surface of the second piston 40, the third piston 50 is slidably supported by the second piston 40.

As shown in FIGS. 1 and 2, the rod member 60 includes a hollow cylindrical rod 61 to which the connecting portion 52 of the third piston 50 is connected to the tip end portion, and a hydraulic cylinder 100 provided at the base end portion of the rod 61. It has a second mounting portion 62 for mounting on the drive target device. Since the displacement portion 73 described later is arranged in the rod 61, the rod 61 may be formed of a plurality of members. The rod 61 and the third piston 50 are connected via a plurality of bolts (not shown). The rod member 60 moves in the cylinder tube 10 in the axial direction together with the third piston 50.

A hollow portion 61a is formed in the rod 61. The hollow portion 61a communicates with the third rod side chamber 4 through the first through hole 61b formed in the rod 61.

The second mounting portion 62 has flow paths 63 and 64 for supplying hydraulic oil from the outside of the hydraulic cylinder 100 or discharging the hydraulic oil to the outside. The flow path 63 communicates with the pipe member 70 described later. The flow path 64 communicates with the hollow portion 61a of the rod 61 through the second through hole 61c formed in the rod 61.

The hydraulic cylinder 100 further includes a pipe member 70 provided in the rod member 60 and guiding hydraulic oil to the anti-rod side chamber 5. The pipe member 70 includes a first pipe portion 71 that is joined to the tip end side of the rod member 60 and communicates with the anti-rod side chamber 5, and a second pipe portion 72 that is supported by the base end side of the rod member 60 and communicates with the flow path 63. , A displacement portion 73 that connects the first pipe portion 71 and the second pipe portion 72. Specifically, one end side of the first pipe portion 71 is inserted into the third through hole 61d formed in the rod 61, and the end portion P is joined to the rod 61 by welding. The other end side of the first pipe portion 71 is connected to the displacement portion 73. One end side of the second pipe portion 72 is press-fitted into the fourth through hole 61e formed in the rod 61 and supported by the rod 61. The other end side of the second pipe portion 72 is connected to the displacement portion 73.

The displacement portion 73 includes an annular first flange portion 73a connected to the first pipe portion 71, an annular second flange portion 73b connected to the second pipe portion 72, and a first flange portion 73a and a second flange. It has a cylindrical elastic member 73c connected to the portion 73b. The first flange portion 73a and the second flange portion 73b are made of metal. The elastic member 73c is formed of an elastic material such as rubber or resin. Since the first flange portion 73a and the second flange portion 73b are annular and the elastic member 73c has a cylindrical shape, the first pipe portion 71 and the second pipe portion 72 communicate with each other through the displacement portion 73. The elastic member 73c has a strength that does not damage even if it receives the pressure of the hydraulic oil guided into the hollow portion of the elastic member 73c or the pressure of the hydraulic oil guided into the hollow portion 61a of the rod 61.

The first pipe portion 71 and the first flange portion 73a, and the second pipe portion 72 and the second flange portion 73b are connected by welding, screw fastening, or the like. The first flange portion 73a and the second flange portion 73b and the elastic member 73c are connected by thermocompression bonding, caulking, or the like. Since the displacement portion 73 has the elastic member 73c, the relative displacement between the first pipe portion 71 and the second pipe portion 72 is allowed by the displacement of the elastic member 73c.

In the hydraulic cylinder 100 configured in this way, hydraulic oil is supplied and discharged to the anti-rod side chamber 5 through the flow path 63 and the pipe member 70, and the flow path 64, the second through hole 61c, the hollow portion 61a, and the first through hole The hydraulic oil is supplied to and discharged from the rod side chamber 1 through 61b. Hereinafter, the flow path communicating with the anti-rod side chamber 5 including the flow path 63 and the pipe member 70 is referred to as a first supply / discharge passage 81, and the flow path 64, the second through hole 61c, the hollow portion 61a, and the first through hole are referred to. The flow path communicating with the rod side chamber 1 including 61b is referred to as a second supply / discharge passage 82.

Next, the operation of the hydraulic cylinder 100 will be described with reference to FIGS. 1 and 3 to 5.

When the hydraulic cylinder 100 is extended, hydraulic oil is supplied to the anti-rod side chamber 5 from a hydraulic source (not shown) such as a pump through the first supply / discharge passage 81, and the first, second, and third rod side chambers 2 , 3 and 4 hydraulic oils are discharged to the tank (not shown) through the second supply / discharge passage 82. In the extension operation of the hydraulic cylinder 100, the first piston 30, the second piston 40, and the third piston 50 move relative to the cylinder tube 10 in this order.

When the hydraulic cylinder 100 extends from the most contracted state shown in FIG. 1, hydraulic oil is supplied to the anti-rod side chamber 5 through the first supply / discharge passage 81. Here, the pressure receiving area that receives the pressure of the anti-rod side chamber 5 is formed so that the first piston 30 has the largest pressure and the third piston 50 has the smallest pressure. That is, the inner piston has a smaller pressure receiving area. Therefore, when the hydraulic cylinder 100 is extended from the most contracted state, the cylinder tube 10 first moves relative to the first piston 30. Specifically, as shown in FIG. 3, the cylinder tube 10 moves upward (upper side in FIG. 3) with respect to the first piston 30.

When the first piston 30 and the cylinder tube 10 move relative to each other, the hydraulic oil in the first rod side chamber 2 flows through the first series communication port 30A, the second rod side chamber 3, the second communication port 40A, and the third rod side chamber 4. (Ii) It is guided to the supply / discharge passage 82 and discharged.

As shown in FIG. 3, when the cylinder tube 10 moves to the extension stroke end of the first piston 30 where the cylinder head 11 abuts on the first piston 30, the first extension side port 11A communicates with the first communication port 30A. do. When the cylinder tube 10 moves to the end of the extension stroke of the first piston 30, the cylinder tube 10 and the first piston 30 are relative to the second piston 40, which has a larger pressure receiving area than the third piston 50 due to the pressure of the anti-rod side chamber 5. Moving. Specifically, as shown in FIG. 4, the cylinder tube 10 and the first piston 30 move upward (upper in FIG. 4) with respect to the second piston 40.

When the first piston 30 and the second piston 40 move relative to each other, the hydraulic oil in the second rod side chamber 3 is guided to the second supply / discharge passage 82 through the second communication port 40A and the third rod side chamber 4 and discharged.

As shown in FIG. 4, when the cylinder tube 10 and the first piston 30 move to the extension stroke end of the second piston 40 where the first support portion 33 of the first piston 30 abuts on the second piston 40, the second extension occurs. The side port 33A communicates with the second communication port 40A.

When the cylinder tube 10 and the first piston 30 move to the end of the extension stroke of the second piston 40, the cylinder tube 10, the first piston 30, and the second piston receive the pressure of the anti-rod side chamber 5 with respect to the third piston 50. 40 moves relative to each other. Specifically, as shown in FIG. 5, the cylinder tube 10, the first piston 30, and the second piston 40 move upward (upper in the middle of FIG. 5) with respect to the third piston 50.

When the third piston 50 and the second piston 40 move relative to each other, the hydraulic oil in the third rod side chamber 4 is discharged through the second supply / discharge passage 82. The cylinder tube 10, the first piston 30, and the second piston 40 move until the second support 43 of the second piston 40 comes into contact with the third piston 50. In this way, as shown in FIG. 5, the hydraulic cylinder 100 is in the fully extended state.

When the hydraulic cylinder 100 contracts, hydraulic oil is supplied from the hydraulic source to the first, second, and third rod side chambers 2, 3 and 4 through the second supply / discharge passage 82, and the hydraulic oil in the anti-rod side chamber 5 is operated. Is discharged to the tank through the first supply / discharge passage 81. In the contraction operation of the hydraulic cylinder 100, the third piston 50, the second piston 40, and the first piston 30 move relative to the cylinder tube 10 in this order. Alternatively, the hydraulic cylinder 100 contracts due to the weight of the drive target device connected to the cylinder tube 10 and the first mounting portion 65. In that case, it is not necessary to supply hydraulic oil to the first, second, and third rod side chambers 2, 3, and 4.

Here, when the hydraulic cylinder 100 is expanded and contracted, compressive and tensile loads act on the piston portion 20 and the rod 61 due to the pressure of the hydraulic oil. Similarly, compressive and tensile loads also act on the pipe member 70 joined to the rod 61. One end of the pipe member 70 is supported by the rod 61, and the other end is joined to the rod 61 by welding (joint portion P). In this way, the rod 61 and the pipe member 70 are integrally formed. On the other hand, since a load acts on the rod 61 also through the third piston 50, a larger load acts on the rod 61 as compared with the pipe member 70. Therefore, the amount of deformation of the rod 61 and the pipe member 70 is different. Therefore, if the pipe member 70 is not provided with the displacement portion 73, a large stress acts on the joint portion P formed by welding the rod 61 and the pipe member 70. When a large stress acts on the joint P for a long period of time, the hollow portion 61a of the rod 61 and the anti-rod side chamber 5, that is, the rod side chamber 1 and the anti-rod side chamber 5 communicate with each other through the joint P, and the hydraulic cylinder operates. May affect.

On the other hand, in the hydraulic cylinder 100 of the present embodiment, the pipe member 70 has a displacement portion 73, and the displacement portion 73 allows a relative displacement between the first pipe portion 71 and the second pipe portion 72. Therefore, even if the amount of deformation of the rod 61 and the pipe member 70 is different, the first pipe portion 71 is displaced with respect to the second pipe portion 72, so that the stress generated at the joint portion P between the rod 61 and the pipe member 70 is generated. Is reduced. Therefore, the rod side chamber 1 and the anti-rod side chamber 5 are prevented from communicating with each other through the joint portion P, and the operation of the hydraulic cylinder 100 is stabilized.

As shown in FIG. 6, the first pipe portion 71 of the pipe member 70 may be joined to the third piston 50, in other words, the piston portion 20, instead of the rod 61. That is, the first pipe portion 71 is joined to the rod 61 or the piston portion 20. Further, the first pipe portion 71 and the rod 61 or the piston portion 20 are not limited to welding, but may be joined by brazing, adhesion, friction welding or the like.

Further, the second pipe portion 72 may be supported by the second mounting portion 62 instead of the rod 61. That is, the second pipe portion 72 may be supported on the base end side of the rod member 60. Further, the method of supporting the second pipe portion 72 by the rod member 60 is not limited to press-fitting, and the rod member 60 and the second pipe portion 72 may be joined by welding.

According to the above embodiment, the following effects are obtained.

The hydraulic cylinder 100 has a displacement portion 73 that allows a relative displacement between the first pipe portion 71 and the second pipe portion 72. Therefore, even if the amount of deformation of the rod 61 and the pipe member 70 is different, the first pipe portion 71 is displaced with respect to the second pipe portion 72, so that the stress generated at the joint portion P between the rod 61 and the pipe member 70 is generated. Is reduced. As a result, the rod side chamber 1 and the anti-rod side chamber 5 are prevented from communicating with each other through the joint portion P, and the operation of the hydraulic cylinder 100 is stabilized.

Next, a modified example of this embodiment will be described.

As shown in FIG. 7, the displacement portion 73 may have a configuration in which the coil portion 73d having a hollow portion through which the hydraulic oil can pass may be provided instead of the elastic member 73c. Further, in this case, the coil portion 73d may be integrally formed with the first pipe portion 71 and the second pipe portion 72 without providing the first flange portion 73a and the second flange portion 73b. That is, the first pipe portion 71, the second pipe portion 72, and the coil portion 73d may be configured by one component. Even with such a configuration, the displacement portion 73 can reduce the stress generated at the joint portion P between the rod 61 and the pipe member 70.

Further, the displacement portion 73 may have a structure having a bellows-shaped cylindrical portion having a hollow portion through which hydraulic oil can pass, instead of the elastic member 73c. Further, in this case, the bellows-shaped cylindrical portion may be integrally formed with the first pipe portion 71 and the second pipe portion 72 without providing the first flange portion 73a and the second flange portion 73b. That is, the first pipe portion 71, the second pipe portion 72, and the bellows-shaped cylindrical portion may be composed of one component. Even with such a configuration, the displacement portion 73 can reduce the stress generated at the joint portion P between the rod 61 and the pipe member 70.

Further, as shown in FIG. 8, the displacement portion 73 of the pipe member 70 is formed by overlapping the end portion of the first pipe portion 71 and the end portion of the second pipe portion 72 so as to be slidable in the axial direction. It may be a configuration. The displacement portion 73 includes a first step portion 173a formed continuously with the outer peripheral surface of the first pipe portion 71 and projecting axially from the end portion of the first pipe portion 71, and an inner peripheral surface of the second pipe portion 72. It has a second step portion 173b that is continuously formed and projects axially from the end portion of the second pipe portion 72. A part of the first step portion 173a and the second step portion 173b are formed so as to overlap each other in the radial direction. By sliding the inner peripheral surface of the first step portion 173a and the outer peripheral surface of the second step portion 173b, the relative displacement of the first pipe portion 71 and the second pipe portion 72 is allowed. Even with such a configuration, the displacement portion 73 can reduce the stress generated at the joint portion P between the rod 61 and the pipe member 70. In addition, in order to prevent the hydraulic oil from leaking between the first stage portion 173a and the second stage portion 173b, a sealing material may be provided between the first stage portion 173a and the second stage portion 173b.

Further, the hydraulic cylinder 100 has a configuration in which the first pipe portion 71 of the pipe member 70 communicates with the rod side chamber 1, and the hollow portion 61a of the rod 61 communicates with the anti-rod side chamber 5 through a through hole formed in the rod 61. You may. That is, the pipe member 70 may have a configuration that is provided in the rod member 60 and guides the hydraulic oil to the rod side chamber 1 or the anti-rod side chamber 5.

Further, the hydraulic cylinder 100 is a three-stage hydraulic cylinder 100 in which three pistons (first piston 30, second piston 40, third piston 50) are provided inside the cylinder tube 10 so as to overlap in the radial direction. On the other hand, the hydraulic cylinder 100 may be a two-stage type in which two pistons are provided inside the cylinder tube 10 in a radial direction, or a hydraulic cylinder 100 in which four or more pistons are provided so as to overlap in a radial direction. Further, the hydraulic cylinder 100 may be provided with only one piston inside the cylinder tube 10.

Further, the hydraulic cylinder 100 may be attached to the drive target device so that the second attachment portion 62 moves up and down with respect to the first attachment portion 65 by the expansion and contraction operation of the hydraulic cylinder 100.

Hereinafter, the configurations, actions, and effects of the embodiments of the present invention will be collectively described.

The hydraulic cylinder (hydraulic cylinder 100) is slidably inserted into the cylinder tube 10, the piston portion 20 slidably inserted into the cylinder tube 10 to partition the rod side chamber 1 and the anti-rod side chamber 5 into the cylinder tube 10, and the cylinder tube 10. A rod member 60 that is inserted and whose tip side (end side on the contraction side) is connected to the piston portion 20, and a pipe member 70 that is provided in the rod member 60 and guides the working fluid to the rod side chamber 1 or the anti-rod side chamber 5. The pipe member 70 includes a first pipe portion 71 joined to the tip end side of the piston portion 20 or the rod member 60, a second pipe portion 72 supported by the proximal end side of the rod member 60, and a first pipe. It has a displacement portion 73 that connects the portion 71 and the second pipe portion 72 and allows a relative displacement between the first pipe portion 71 and the second pipe portion 72.

In this configuration, the displacement of the displacement portion 73 of the pipe member 70 reduces the stress generated at the joint portion P of the pipe member 70 with respect to the piston portion 20 or the rod member 60. Therefore, it is prevented that the rod side chamber 1 and the anti-rod side chamber 5 communicate with each other through the joint portion P, and the operation of the fluid pressure cylinder is stabilized.

In the fluid pressure cylinder, the displacement portion 73 has a cylindrical elastic member 73c.

In the fluid pressure cylinder, the displacement portion 73 has a coil portion 73d having a hollow portion through which the working fluid can pass.

The fluid pressure cylinder is characterized in that the displacement portion 73 is formed by overlapping the end portion of the first pipe portion 71 and the end portion of the second pipe portion 72 so as to be slidable in the axial direction.

In these configurations, the displacement portion 73 can reduce the stress generated in the welded portion P between the rod member 60 and the pipe member 70.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. No.

1 ... Rod side chamber, 5 ... Anti-rod side chamber, 10 ... Cylinder tube, 20 ... Piston part, 60 ... Rod member, 70 ... Pipe member, 71 ... First pipe part, 72 ... Second pipe part, 73 ... Displacement part, 73c ... Elastic member, 73d ... Coil part, 100 ... Hydraulic cylinder (fluid pressure cylinder)

Claims (4)

Cylinder tube and
A piston portion that is slidably inserted into the cylinder tube and separates a rod side chamber and an anti-rod side chamber in the cylinder tube.
A rod member that is inserted into the cylinder tube and whose tip end side is connected to the piston portion.
A pipe member provided in the rod member and guiding a working fluid to the rod side chamber or the anti-rod side chamber is provided.
The pipe member is
The first pipe portion joined to the tip side of the piston portion or the rod member, and
A second pipe portion supported on the base end side of the rod member and
A fluid pressure cylinder characterized by connecting the first pipe portion and the second pipe portion and having a displacement portion that allows a relative displacement between the first pipe portion and the second pipe portion. The fluid pressure cylinder according to claim 1, wherein the displacement portion has a cylindrical elastic member. The fluid pressure cylinder according to claim 1, wherein the displacement portion has a coil portion having a hollow portion through which a working fluid can pass. The fluid pressure according to claim 1, wherein the displacement portion is formed by overlapping the end portion of the first pipe portion and the end portion of the second pipe portion so as to be slidable in the axial direction. Cylinder.

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