JP2017166519A - Fluid pressure cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pressure cylinder which can easily adjust cushion performance.SOLUTION: A fluid pressure cylinder comprises a cylinder head 40 into which a piston rod 30 penetrates, and a cushion mechanism 70 for decelerating the piston rod 30 in the vicinity of a stroke end. The cushion mechanism 70 comprises a cushion ring 71 intruding into the cylinder head 40, and a cushion passage 72 which introduces a working fluid of a pressure chamber 2 to a feed/discharge port 10a when the cushion ring 71 intrudes into the cylinder head 40, and makes cushion pressure act on the pressure chamber 2. The cylinder head 40 comprises a first cylinder head 50, and a second cylinder head 60 which is relatively movable to the first cylinder head 50 in an axial direction of a cylinder tube 10 by an operation from the outside. A flow passage cross section area of the cushion passage 72 is changed by the relative movement of the second cylinder head 60 to the first cylinder head 50.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fluid pressure cylinder used as an actuator.

  2. Description of the Related Art As a hydraulic cylinder used for a hydraulic excavator or the like, a cylinder having a cushion mechanism that generates a cushion pressure near a stroke end and decelerates a piston rod is known.

  As a hydraulic cylinder of this type, Patent Document 1 discloses a passage that is formed in the fitting portion 3 of the first covering member 2 that covers the cylinder tube 1 and closes the end surface opening, and extends from the working chamber 9 toward the port 11. 15, an opening 17 and a passage 15, restricting the flow rate of the working fluid in the working chamber 9 and discharging it toward the port 11, and the piston rod 6 adjacent to the piston 5. What is provided with the cushion ring 19 provided is disclosed. When the piston rod 6 moves in the direction in which the working fluid in the working chamber 9 is discharged, the cushion ring 19 is fitted into the enlarged diameter hole 13a in the vicinity of the moving end and plays a role of closing the enlarged diameter hole 13a. As a result, the working fluid in the working chamber 9 is discharged from the opening 17 via the throttle hole 18 toward the port 11 while restricting the flow rate, and a cushioning action is imparted at the moving end of the piston rod 6. It has come to be.

JP 2001-82415 A

  In the hydraulic cylinder described in Patent Document 1, when adjusting the cushion performance, it is necessary to remove the hydraulic cylinder from the airframe and to disassemble the hydraulic cylinder to adjust the diameter of the throttle hole.

  As described above, in the hydraulic cylinder described in Patent Document 1, it takes a lot of time to adjust the cushion performance, resulting in an increase in cost.

  The present invention has been made in view of the above problems, and an object thereof is to provide a fluid pressure cylinder capable of easily adjusting the cushion performance.

  A first invention is a fluid pressure cylinder in which a piston rod provided with a piston is reciprocally provided in a cylinder tube, and is provided at an opening end portion of the cylinder tube, and a cylinder head through which the piston rod is inserted, A cushioning mechanism for decelerating the piston rod near the stroke end when the working fluid in the pressure chamber is discharged through the supply / exhaust port and the piston rod strokes, and the cushion mechanism is provided on the piston rod. An annular cushion ring that enters the cylinder head in the vicinity, and a cushion passage that is formed in the cylinder head and guides the working fluid in the pressure chamber to the supply / discharge port and applies the cushion pressure to the pressure chamber when the cushion ring enters the cylinder head And the cylinder head is provided on the cylinder tube And a second cylinder head that can be moved relative to the first cylinder head in the axial direction of the cylinder tube by an external operation, and the second cylinder head is relative to the first cylinder head. The cross-sectional area of the cushion passage changes as a result of relative movement.

  In the first invention, the cylinder head includes a first cylinder head provided on the cylinder tube and a second cylinder head operable from the outside, and the cushion passage is formed by relative movement of the second cylinder head with respect to the first cylinder head. The cross-sectional area of the channel changes. Therefore, the adjustment of the cushion performance does not need to be disassembled by removing the fluid pressure cylinder from the airframe, and can be performed with the fluid pressure cylinder attached to the airframe.

  According to a second aspect of the present invention, the cushion passage has a main passage formed in communication with the pressure chamber and a flow passage cross-sectional area smaller than that of the main passage, and is caused by relative movement of the second cylinder head with respect to the first cylinder head. A throttle passage having a variable path cross-sectional area, and the throttle passage includes a plurality of passages formed at predetermined intervals in the axial direction of the cylinder tube.

  According to a third aspect of the present invention, a cushion passage is formed in the first cylinder head, and the second cylinder head includes a cylindrical portion into which the cushion ring enters along the inner peripheral surface. A cushion adjusting portion that is slidable along the inner peripheral surface of one cylinder head, and that has a cushion adjusting portion that blocks the throttle passage, and an opening portion that has a smaller outer diameter than the cushion adjusting portion and opens the throttle passage. It is characterized by that.

  In the second and third aspects of the invention, the cross-sectional area of the cushion passage is determined by the number of throttle passages that are blocked by the relative movement of the second cylinder head with respect to the first cylinder head. Easy to do.

  According to a fourth aspect of the present invention, the first cylinder head is disposed so as to face the pressure chamber, and the first cylinder head includes a cushion passage, an annular portion into which the cushion ring enters and slides along the inner peripheral surface, It is characterized by having.

  In the fourth invention, the stroke position of the fluid pressure cylinder at which the cushion action starts to be effective can be made constant regardless of the relative movement of the second cylinder head with respect to the first cylinder head.

  The fifth invention is characterized in that the second cylinder head is provided in the cylinder tube.

  The sixth invention is characterized by further comprising an adjustment member provided between the cylinder tube and the second cylinder head and defining a relative position of the second cylinder head with respect to the first cylinder head.

  The seventh invention is characterized in that the second cylinder head is provided in the first cylinder head.

  The eighth invention is characterized by further comprising an adjusting member that is provided between the first cylinder head and the second cylinder head and defines a relative position of the second cylinder head with respect to the first cylinder head.

  In the fifth to eighth aspects, since the relative movement of the second cylinder head with respect to the first cylinder head can be defined by changing the thickness of the adjustment member, the cushion performance can be easily adjusted.

  According to the present invention, the cushion performance can be easily adjusted.

It is a partial sectional view of the fluid pressure cylinder concerning a 1st embodiment of the present invention, and shows the state where a piston rod exists in a normal stroke range. The piston rod is in the vicinity of the stroke end when the fluid pressure cylinder is extended. It is a partial cross section figure showing the modification of the fluid pressure cylinder concerning a 1st embodiment of the present invention, and shows the state where a piston rod is near the stroke end at the time of extension operation of a fluid pressure cylinder. It is a partial cross section figure of the fluid pressure cylinder which concerns on 2nd Embodiment of this invention.

  Hereinafter, a fluid pressure cylinder according to an embodiment of the present invention will be described with reference to the drawings.

<First Embodiment>
First, a hydraulic cylinder 100 according to a first embodiment of the present invention will be described with reference to FIGS.

  The hydraulic cylinder 100 is used as an actuator mounted on a construction machine or an industrial machine. For example, the hydraulic cylinder 100 is used as an arm cylinder mounted on a hydraulic excavator, and when the hydraulic cylinder 100 expands and contracts, the arm of the hydraulic excavator rotates.

  As shown in FIGS. 1 and 2, the hydraulic cylinder 100 includes a cylindrical cylinder tube 10, a rod side chamber 2 and an anti-rod side chamber 3 that are slidably inserted into the cylinder tube 10 and use the inside of the cylinder tube 10 as a pressure chamber. And a piston rod 30 which is connected to one end and extends to the outside of the cylinder tube 10 and reciprocates in the cylinder tube 10.

  The rod side chamber 2 and the non-rod side chamber 3 communicate with a hydraulic pump or a tank as a fluid pressure supply source through a switching valve. When one of the rod side chamber 2 and the non-rod side chamber 3 communicates with the hydraulic pump, the other communicates with the tank. The hydraulic cylinder 100 expands and contracts when hydraulic oil (working fluid) is guided from the hydraulic pump to the rod side chamber 2 or the non-rod side chamber 3 and the piston rod 30 moves in the axial direction. As the working fluid, for example, a water-soluble alternative liquid may be used instead of the working oil.

  The cylinder tube 10 is formed with a main port 10a that penetrates in the radial direction and serves as a supply / discharge port for supplying / discharging hydraulic oil to / from the rod side chamber 2. A hydraulic pipe is connected to the main port 10a, and the hydraulic pipe is connected to a hydraulic pump or a tank through a switching valve.

  A cylinder head 40 is provided at the opening end of the cylinder tube 10. The piston rod 30 is slidably inserted into the cylinder head 40 and supported by the cylinder head 40.

  The piston rod 30 includes a small-diameter portion 31 formed at the front end portion and to which the piston 20 is fastened, a large-diameter portion 32 that is supported by the cylinder head 40 and has a larger diameter than the small-diameter portion 31, and the small-diameter portion 31 and the large-diameter. Medium-diameter portion 33 formed between the portions 32 and provided with an annular cushion ring 71 described later. The diameter of the medium diameter portion 33 is larger than the small diameter portion 31 and smaller than the large diameter portion 32. Since the cushion ring 71 is sandwiched between the piston 20 and the large diameter portion 32, the cushion ring 71 does not come out of the piston rod 30.

  When the hydraulic pump communicates with the rod side chamber 2 and the tank communicates with the anti-rod side chamber 3, the hydraulic oil is supplied to the rod side chamber 2 through the main port 10a, and the hydraulic oil in the anti-rod side chamber 3 is discharged to the tank. The As a result, the piston rod 30 moves rightward in FIG. 1 and the hydraulic cylinder 100 is contracted.

  On the other hand, when the hydraulic pump communicates with the anti-rod side chamber 3 and the tank communicates with the rod side chamber 2, the hydraulic oil is supplied to the anti-rod side chamber 3, and the hydraulic oil in the rod side chamber 2 is supplied to the tank through the main port 10a. Discharged. As a result, the piston rod 30 moves leftward in FIG. 1 and the hydraulic cylinder 100 is extended. The hydraulic cylinder 100 includes a cushion mechanism 70 that decelerates the piston rod 30 in the vicinity of the stroke end during the extension operation. FIG. 1 shows a state in which the piston rod 30 is in the normal stroke region, and FIG. 2 shows that the piston rod 30 is in the vicinity of the stroke end when the hydraulic cylinder 100 is extended, and the cushion mechanism 70 exhibits a cushioning action. Indicates the state.

  Hereinafter, the cushion mechanism 70 and the cylinder head 40 will be described in detail with reference to FIGS. 1 and 2.

  The cushion mechanism 70 is provided on the piston rod 30 and is formed on the cylinder head 40 and an annular cushion ring 71 that enters the cylinder head 40 near the stroke end when the hydraulic cylinder 100 is extended. The cushion ring 71 is formed in the cylinder head. And a cushion passage 72 that guides the hydraulic oil in the rod-side chamber 2 to the main port 10a when entering 40.

  The cylinder head 40 is a cylindrical first cylinder head 50 provided on the cylinder tube 10 and a cylindrical shape provided on the cylinder tube 10 and relatively movable in the axial direction of the cylinder tube 10 with respect to the first cylinder head 50. The second cylinder head 60 is provided.

  The first cylinder head 50 and the second cylinder head 60 are arranged along the inner peripheral surface of the cylinder tube 10 and are partially overlapped with each other in the radial direction. The first cylinder head 50 is disposed in the cylinder tube 10 so as to face the rod side chamber 2. Most of the second cylinder head 60 is disposed in the cylinder tube 10, and a part of the second cylinder head 60 is disposed so as to be exposed from the opening end of the cylinder tube 10.

  The first cylinder head 50 includes a fastening portion 51 having a screw 51a formed on the outer peripheral surface, a small diameter portion 52 having a smaller outer diameter compared to the fastening portion 51, and an outer peripheral surface along the inner peripheral surface of the cylinder tube 10. The outer diameter is larger than the fastening part 51, and the outer peripheral surface has a large-diameter part 53 along the inner peripheral surface of the cylinder tube 10. Since the male screw 51a of the fastening portion 51 is formed on the inner peripheral surface of the cylinder tube 10, the end surface of the fastening portion 51 is brought to the inner peripheral surface of the cylinder tube 10 by screwing the male screw 51a into the screw and moving the first cylinder head 50 forward. It is pressed by the formed step portion 10b. On the outer peripheral surface of the large-diameter portion 53, an annular O-ring 54 that seals between the inner peripheral surface of the cylinder tube 10 is provided.

  A cushion passage 72 is formed in the first cylinder head 50. The cushion passage 72 is formed to communicate with the rod side chamber 2 and is formed to open to the main passage 73 extending linearly in the axial direction and the inner peripheral surface of the first cylinder head 50 and to extend linearly in the radial direction. And a throttle passage 74. The main passage 73 and the throttle passage 74 are formed in communication with each other.

  The throttle passage 74 includes a plurality of passages 74 a, 74 b, 74 c, and the throttle passages 74 a, 74 b, 74 c are formed at predetermined intervals in the axial direction of the cylinder tube 10. The total channel cross-sectional area of each throttle passage 74a, 74b, 74c is smaller than the channel cross-sectional area of the main passage 73. Therefore, the flow path resistance imparted to the hydraulic oil passing through the cushion passage 72 is predominantly the flow path resistance due to the throttle passage 74. The flow passage cross-sectional areas of the throttle passages 74a, 74b, and 74c are the same.

  In the present embodiment, the throttle passage 74 includes three passages. However, the number of the passages constituting the throttle passage 74 may be two or more. Further, the flow passage cross-sectional areas of the respective throttle passages 74 may be different from each other.

  The second cylinder head 60 includes a fastening portion 61 having a screw 61a formed on the outer peripheral surface, and a cylindrical portion 62 having a smaller outer diameter than the fastening portion 51 and into which the cushion ring 71 enters along the inner peripheral surface. The operation part 63 is provided outside the cylinder tube 10 and can be operated by an operator.

  An annular passage 79 communicating with the rod side chamber 2 is formed between the inner peripheral surface of the cylindrical portion 62 of the second cylinder head 60 and the outer peripheral surface of the large diameter portion 32 of the piston rod 30. The cylindrical portion 62 is formed with a subport 64 that is formed so as to penetrate in the radial direction and communicate with the annular passage 79. A pressure chamber 78 that connects the main port 10 a and the subport 64 is formed between the first cylinder head 50 and the second cylinder head 60. As described above, the rod side chamber 2 and the main port 10 a communicate with each other through the annular passage 79, the sub port 64, and the pressure chamber 78.

  A cushion adjustment portion 62a that is slidable along the inner peripheral surface of the first cylinder head 50 on the outer peripheral surface of the cylindrical portion 62 and that blocks the throttle passage 74 formed in the first cylinder head 50, and a cushion adjustment An opening 62 b that has a smaller outer diameter than the portion 62 a and opens the throttle passage 74 is formed side by side in the axial direction of the cylinder tube 10. Between the outer peripheral surface of the opening 62b and the inner peripheral surface of the first cylinder head 50, an annular communication passage 77 that is always in communication with the pressure chamber 78 is formed. The flow passage cross-sectional area of the communication passage 77 is larger than the total flow passage cross-sectional area of each passage 74a. As described above, the rod side chamber 2 and the main port 10a communicate with each other through the cushion passage 72, the communication passage 77, and the pressure chamber 78, and in order for hydraulic oil to pass through this passage, the flow passage resistance by the restriction passage 74 dominates. It becomes the target.

  Since the male screw 61a of the fastening portion 61 of the second cylinder head 60 is formed on the inner peripheral surface of the cylinder tube 10, the second cylinder head 60 is moved forward or backward by being screwed into the screw and moving the second cylinder head 60 forward or backward. It can be moved relative to the first cylinder head 50. As a result, the number of throttle passages 74 blocked by the cushion adjustment portion 62a of the second cylinder head 60 changes. Thus, by moving the second cylinder head 60 relative to the first cylinder head 50, the flow passage cross-sectional area of the throttle passage 74 can be changed.

  The flow passage cross-sectional area of the throttle passage 74 is sufficiently smaller than the flow passage cross-sectional areas of the annular passage 79 and the subport 64. Therefore, when the piston rod 30 is in the normal stroke region during the extension operation of the hydraulic cylinder 100 (see FIG. 1), the hydraulic oil in the rod side chamber 2 flows into the annular passage 79, the sub port 64, the pressure chamber 78, and the main port 10a. It is discharged through.

  On the other hand, when the piston rod 30 is near the stroke end during the extension operation of the hydraulic cylinder 100 (see FIG. 2), the cushion ring 71 enters the cylindrical portion 62 of the second cylinder head 60. Here, the outer diameter of the cushion ring 71 is larger than the outer diameter of the large diameter portion 32 of the piston rod 30 and slightly smaller than the inner diameter of the cylindrical portion 62. Therefore, when the cushion ring 71 enters the cylindrical portion 62 of the second cylinder head 60, the flow of the hydraulic oil from the rod side chamber 2 to the sub port 64 is substantially blocked, and the hydraulic oil in the rod side chamber 2 flows into the cushion passage 72, the communication passage. The gas is discharged through the passage 77, the pressure chamber 78, and the main port 10a. That is, the hydraulic oil in the rod side chamber 2 bypasses the annular passage 79 and the subport 64 and is discharged through the cushion passage 72. Since the flow passage cross-sectional area of the throttle passage 74 is sufficiently smaller than the flow passage cross-sectional areas of the annular passage 79 and the sub-port 64, the pressure in the rod side chamber 2 increases and the piston rod 30 decelerates. Thus, the cushioning action is exhibited near the stroke end when the hydraulic cylinder 100 is extended. Hereinafter, the pressure in the rod side chamber 2 when the cushion action is exerted is referred to as “cushion pressure”.

  The adjustment of the cushion pressure is determined by the number of throttle passages 74 blocked by the cushion adjustment unit 62a. Specifically, if the second cylinder head 60 is moved forward, the number of throttle passages 74 blocked by the cushion adjusting portion 62a is reduced, and the flow passage sectional area of the throttle passage 74 is increased. Becomes smaller. Therefore, the deceleration rate of the piston rod 30 becomes small. On the other hand, if the second cylinder head 60 is moved backward, the number of throttle passages 74 blocked by the cushion adjusting portion 62a increases, and the flow passage cross-sectional area of the throttle passage 74 decreases, so that the cushion pressure increases relatively. Therefore, the deceleration rate of the piston rod 30 increases.

  The forward or backward movement of the second cylinder head 60 is performed by operating the operation portion 63 exposed to the outside of the cylinder tube 10. In this way, the cushion pressure can be freely set by operating the operation portion 63 to adjust the relative position of the second cylinder head 60 with respect to the first cylinder head 50. If the relationship between the relative position of the second cylinder head 60 with respect to the first cylinder head 50 and the number of blocked throttle passages 74 is known in advance, the cushion pressure can be adjusted appropriately.

  The operation portion 63 is formed to face the end surface of the cylinder tube 10. A shim 66 is provided between the end face of the operation portion 63 and the end face of the cylinder tube 10 as an adjustment member that defines the relative position of the second cylinder head 60 with respect to the first cylinder head 50. By changing the thickness of the shim 66, the number of throttle passages 74 blocked by the cushion adjusting portion 62a is changed. If a plurality of shims having different thicknesses are prepared and the number of throttle passages 74 to be blocked is changed corresponding to the thickness of the shim, the cushion pressure can be easily changed.

  Since the shim 66 is formed of an elastic material, when the second cylinder head 60 is tightened, the shim 66 is compressed between the operation portion 63 and the cylinder tube 10 to generate a repulsive force. Thereby, loosening of the external thread 61a of the second cylinder head 60 is prevented. In this way, the shim 66 defines the relative position of the second cylinder head 60 with respect to the first cylinder head 50 and also functions as a loosening stopper for the male screw 61a of the second cylinder head 60.

  An annular O-ring 67 is provided on the outer peripheral surface of the second cylinder head 60 to seal the space between the inner peripheral surface of the cylinder tube 10. A seal member 68 that seals between the outer peripheral surface of the piston rod 30 and a dust seal 69 that prevents dust from entering from the outside are provided on the inner peripheral surface of the second cylinder head 60.

  In the fully extended state of the hydraulic cylinder 100, the cushion ring 71 does not close the sub port 64. Therefore, when the hydraulic cylinder 100 is contracted from the most extended state, the hydraulic oil supplied through the main port 10 a is guided to the annular passage 79 through the pressure chamber 78 and the subport 64 and acts on the end of the cushion ring 71. To do. As a result, the hydraulic cylinder 100 starts to contract smoothly.

  According to the above 1st Embodiment, there exists an effect shown below.

  The cylinder head 40 includes a first cylinder head 50 provided in the cylinder tube 10 and a second cylinder head 60 that can be operated from the outside, and a cushion passage is formed by relative movement of the second cylinder head 60 with respect to the first cylinder head 50. The cross-sectional area of 72 changes. Therefore, the adjustment of the cushion performance does not require the hydraulic cylinder 100 to be detached from the body and disassembled, and can be performed while the hydraulic cylinder 100 is attached to the body, so that the cushion performance can be easily adjusted. Thus, the cushion performance can be adjusted in a short time and at a low cost.

  Below, the modification of the said 1st Embodiment is demonstrated.

  (1) In the first embodiment, the case where the throttle passage 74 is composed of a plurality of passages has been described. However, the throttle passage 74 may be constituted by only one passage. In this case, if the relationship between the relative position of the second cylinder head 60 with respect to the first cylinder head 50 and the flow path cross-sectional area of the throttle passage 74 is grasped in advance, the cushion pressure can be adjusted appropriately.

  (2) In the first embodiment, the form in which the first cylinder head 50 and the second cylinder head 60 are screwed to the cylinder tube 10 has been described. In order to prevent the screws from loosening, snap rings are provided between the first cylinder head 50 and the cylinder tube 10 and between the second cylinder head 60 and the cylinder tube 10, and the first cylinder head 50 and the second cylinder head 10 with respect to the cylinder tube 10 are provided. The movement of the two-cylinder head 60 in the axial direction may be restricted.

  (3) As shown in FIG. 3, an annular portion 55 into which the cushion ring 71 enters may be formed on the inner peripheral surface of the first cylinder head 50. The inner diameter of the annular portion 55 is slightly larger than the outer diameter of the cushion ring 71. Therefore, when the cushion ring 71 enters the annular portion 55, the cushion ring 71 slides along the inner peripheral surface of the annular portion 55.

  Since the annular portion 55 on which the cushion ring 71 slides is provided in the first cylinder head 50 fixed to the cylinder tube 10, the stroke position of the hydraulic cylinder 100 at which the cushion action starts to be effective is set to the position of the second cylinder head 60. Regardless, it can always be constant.

  When the annular portion 55 is provided in the first cylinder head 50, resistance is given to the flow of hydraulic oil between the cushion ring 71 and the cylindrical portion 62 when the cushion ring 71 enters the cylindrical portion 62. In order to prevent this, it is desirable that the inner diameter of the cylindrical portion 62 is sufficiently larger than the outer diameter of the cushion ring 71.

Second Embodiment
Next, a hydraulic cylinder 200 according to a second embodiment of the present invention will be described with reference to FIG. Below, a different point from the hydraulic cylinder 100 which concerns on the said 1st Embodiment is demonstrated, the same code | symbol is attached | subjected to the structure same as the hydraulic cylinder 100 in drawing, and description is abbreviate | omitted.

  The hydraulic cylinder 200 is different from the cylinder head 40 of the hydraulic cylinder 100 in the configuration of a cylinder head 41 provided at the opening end of the cylinder tube 10 and through which the piston rod 30 is inserted.

  The cylinder head 41 of the hydraulic cylinder 200 is provided in a cylindrical first cylinder head 80 provided in the cylinder tube 10 and in the first cylinder head 80, and in the axial direction of the cylinder tube 10 with respect to the first cylinder head 80. A cylindrical second cylinder head 90 capable of relative movement.

  The first cylinder head 80 corresponds to the first cylinder head 50 of the hydraulic cylinder 100, and the second cylinder head 90 corresponds to the second cylinder head 60 of the hydraulic cylinder 100. The first cylinder head 50 of the hydraulic cylinder 100 is screwed to the cylinder tube 10, whereas the first cylinder head 80 is fastened to the cylinder tube 10 by a bolt 89. Further, the second cylinder head 60 of the hydraulic cylinder 100 is provided in the cylinder tube 10, whereas the second cylinder head 90 is provided in the first cylinder head 80.

  The first cylinder head 80 includes a cylindrical main body portion 81 that is partially provided along the inner peripheral surface of the cylinder tube 10, a flange portion 82 that is formed so as to protrude in the radial direction from the outer peripheral surface of the main body portion 81, Is provided.

  The first cylinder head 80 is fixed to the cylinder tube 10 via a bolt 89 that passes through a fastening hole 82 a formed in the flange portion 82.

  A main port 10 a and a cushion passage 72 are formed in the first cylinder head 80. Further, an annular portion 55 is formed on the inner peripheral surface of the first cylinder head 80 to make the stroke position of the hydraulic cylinder 200 constant when the cushion ring 71 enters and the cushioning action starts to work.

  The second cylinder head 90 has an outer diameter larger than that of the fastening portion 91 in which the screw 91a is formed on the outer peripheral surface, the cylindrical portion 92 into which the cushion ring 71 enters along the inner peripheral surface, and the fastening portion 51. And an operating portion 93 provided outside the cylinder tube 10 and operable by an operator.

  An annular passage 79 communicating with the rod side chamber 2 is formed between the inner peripheral surface of the cylindrical portion 92 of the second cylinder head 90 and the outer peripheral surface of the large diameter portion 32 of the piston rod 30. The cylindrical portion 92 is formed with a sub-port 64 that is formed so as to penetrate in the radial direction and communicate with the annular passage 79. A pressure chamber 78 that connects the main port 10 a and the subport 64 is formed between the first cylinder head 80 and the second cylinder head 90.

  A cushion adjusting portion 92a that is slidable along the inner peripheral surface of the first cylinder head 80 on the outer peripheral surface of the cylindrical portion 92 and blocks the throttle passage 74 formed in the first cylinder head 80, and a cushion adjustment An opening 92b having an outer diameter smaller than that of the portion 92a and opening the throttle passage 74 is formed side by side in the axial direction of the cylinder tube 10.

  The forward or backward movement of the second cylinder head 90 is performed by operating the operation portion 63 exposed to the outside of the cylinder tube 10. As described above, in the hydraulic cylinder 200 as well, by operating the operation unit 63 and adjusting the relative position of the second cylinder head 60 with respect to the first cylinder head 50 as in the hydraulic cylinder 100 according to the first embodiment. The cushion pressure can be set freely.

  Between the end surface of the main body 81 of the first cylinder head 80 and the end surface of the operation portion 93 of the second cylinder head 90 as an adjustment member that defines the relative position of the second cylinder head 90 with respect to the first cylinder head 80. A shim 66 is provided.

  Also in the second embodiment described above, the same operational effects as in the first embodiment are obtained.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  In the present embodiment, the piston rod 30 provided with the piston 20 is a hydraulic cylinder 100, 200 provided in the cylinder tube 10 so as to be able to reciprocate, and is provided at the open end of the cylinder tube 10. Are inserted into the cylinder heads 40, 41, the rod side chamber 2 defined between the cylinder head 40 and the piston 20, the main port 10a for supplying and discharging hydraulic oil to the rod side chamber 2, and the rod through the main port 10a. And a cushion mechanism 70 that decelerates the piston rod 30 in the vicinity of the stroke end when the hydraulic oil in the side chamber 2 is discharged and the piston rod 30 strokes. The cushion mechanism 70 is provided on the piston rod 30 and is disposed at the stroke end. An annular cushion ring 71 entering the cylinder head 40 in the vicinity; A cushion passage 72 formed in the cylinder heads 40 and 41, which guides the hydraulic oil in the rod side chamber 2 to the main port 10a and applies a cushion pressure to the rod side chamber 2 when the cushion ring 71 enters the cylinder heads 40 and 41. The cylinder heads 40 and 41 are relatively movable in the axial direction of the cylinder tube 10 with respect to the first cylinder heads 50 and 80 and the first cylinder heads 50 and 80 by an external operation. The second cylinder heads 60 and 90 are provided, and the second cylinder heads 60 and 90 move relative to the first cylinder heads 50 and 80, whereby the flow path cross-sectional area of the cushion passage 72 changes.

  In this configuration, the cylinder heads 40 and 41 include first cylinder heads 50 and 80 provided on the cylinder tube 10 and second cylinder heads 60 and 90 that can be operated from the outside, and the first cylinder heads 50 and 80 are provided. The flow passage cross-sectional area of the cushion passage 72 changes due to the relative movement of the second cylinder heads 60 and 90 with respect to the cylinder head. Therefore, the adjustment of the cushion performance is not required to remove the hydraulic cylinders 100 and 200 from the airframe and disassemble them, and can be performed while the hydraulic cylinders 100 and 200 are attached to the airframe. Therefore, the cushion performance can be easily adjusted.

  Further, in the present embodiment, the cushion passage 72 has a main passage 73 formed in communication with the rod side chamber 2 and a flow passage cross-sectional area smaller than that of the main passage 73, and the cushion passage 72 has a first passage relative to the first cylinder heads 50, 80. A throttle passage 74 whose flow path cross-sectional area is changed by relative movement of the two cylinder heads 60, 90, and the throttle passage 74 is formed with a plurality of passages 74a formed at predetermined intervals in the axial direction of the cylinder tube 10. , 74b, 74c.

  In the present embodiment, the first cylinder heads 50 and 80 have a cushion passage 72 formed therein, and the second cylinder heads 60 and 90 have cylindrical portions 62 and 92 into which the cushion ring 71 enters along the inner peripheral surface. Cushion adjusting portions 62a and 92a that are slidable along the inner peripheral surface of the first cylinder heads 50 and 80 on the outer peripheral surfaces of the cylindrical portions 62 and 92, and that block the throttle passage 74, and cushion adjustments Opening portions 62b and 92b that have a smaller outer diameter than the portions 62a and 92a and open the throttle passage 74 are formed.

  In these configurations, the flow passage cross-sectional area of the cushion passage 72 is determined by the number of throttle passages 74 that are blocked by the relative movement of the second cylinder heads 60 and 90 with respect to the first cylinder heads 50 and 80. Easy to adjust the road cross-sectional area.

  Further, in the present embodiment, the first cylinder heads 50 and 80 are disposed facing the rod side chamber 2, and the first cylinder heads 50 and 80 are inserted into the cushion passage 72 and the cushion ring 71 so as to enter the inner peripheral surface. And an annular portion 55 that slides along.

  In this configuration, the stroke positions of the hydraulic cylinders 100 and 200 at which the cushion action starts to work can be made constant regardless of the relative movement of the second cylinder heads 60 and 90 with respect to the first cylinder heads 50 and 80.

  In the present embodiment, the second cylinder head 60 is provided on the cylinder tube 10.

  In the present embodiment, a shim 66 is further provided between the cylinder tube 10 and the second cylinder head 60 and defining the relative positions of the second cylinder heads 60 and 90 with respect to the first cylinder heads 50 and 80.

  In the present embodiment, the second cylinder head 90 is provided on the first cylinder head 80.

  Further, in the present embodiment, an adjustment member 66 that is provided between the first cylinder head 80 and the second cylinder head 90 and defines the relative position of the second cylinder head 90 with respect to the first cylinder head 80 is further provided.

  In these configurations, since the relative movement of the second cylinder heads 60 and 90 with respect to the first cylinder heads 50 and 80 can be defined by changing the thickness of the shim 66, the cushion performance can be easily adjusted. it can.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

100, 200 ... Hydraulic cylinder (fluid pressure cylinder), 1 ... Hydraulic cylinder, 2 ... Rod side chamber, 10 ... Cylinder tube, 10a ... Main port (supply / discharge port), 30 ... Piston rod, 40, 41 ... cylinder head, 50, 60 ... first cylinder head, 55 ... annular portion, 60, 90 ... second cylinder head, 62, 92 ... cylindrical portion 62a, 92a ... Cushion adjustment part, 62b, 92b ... Opening part, 63, 93 ... Operation part, 64 ... Subport, 66 ... Shim (adjustment member), 70 ... Cushion Mechanism: 71 ... Cushion ring, 72 ... Cushion passage, 73 ... Main passage, 74, 74a, 74b, 74c ... Restriction passage, 79 ... Ring passage

Claims (8)

A piston rod provided with a piston is a fluid pressure cylinder provided in a cylinder tube so as to freely reciprocate,
A cylinder head provided at an opening end of the cylinder tube and through which the piston rod is inserted;
A pressure chamber defined between the cylinder head and the piston;
A supply and discharge port for supplying and discharging a working fluid to and from the pressure chamber;
A cushion mechanism that decelerates the piston rod near the stroke end when the working fluid of the pressure chamber is discharged through the supply / discharge port and the piston rod strokes,
The cushion mechanism is
An annular cushion ring provided on the piston rod and entering the cylinder head near the stroke end;
A cushion passage formed in the cylinder head and guiding the working fluid of the pressure chamber to the supply / exhaust port when the cushion ring enters the cylinder head and applying a cushion pressure to the pressure chamber;
The cylinder head is
A first cylinder head provided on the cylinder tube;
A second cylinder head movable relative to the first cylinder head in the axial direction of the cylinder tube by an external operation;
The fluid pressure cylinder according to claim 1, wherein a flow path cross-sectional area of the cushion passage is changed by the relative movement of the second cylinder head with respect to the first cylinder head. The cushion passage is
A main passage formed in communication with the pressure chamber;
A throttle passage having a small passage cross-sectional area as compared to the main passage, and a passage cross-sectional area changing by relative movement of the second cylinder head with respect to the first cylinder head,
The fluid pressure cylinder according to claim 1, wherein the throttle passage includes a plurality of passages formed at predetermined intervals in an axial direction of the cylinder tube. The cushion passage is formed in the first cylinder head,
The second cylinder head includes a cylindrical portion into which the cushion ring enters along an inner peripheral surface,
The outer peripheral surface of the cylindrical portion is slidable along the inner peripheral surface of the first cylinder head, and has a smaller outer diameter than the cushion adjustment portion and the cushion adjustment portion that blocks the throttle passage. The fluid pressure cylinder according to claim 2, wherein an opening portion that opens the throttle passage is formed. The first cylinder head is disposed facing the pressure chamber;
4. The first cylinder head according to claim 1, wherein the first cylinder head includes the cushion passage and an annular portion that the cushion ring enters and slides along an inner peripheral surface. 5. The fluid pressure cylinder described.   The fluid pressure cylinder according to any one of claims 1 to 4, wherein the second cylinder head is provided in the cylinder tube.   The fluid according to claim 5, further comprising an adjustment member provided between the cylinder tube and the second cylinder head and defining a relative position of the second cylinder head with respect to the first cylinder head. Pressure cylinder.   The fluid pressure cylinder according to any one of claims 1 to 4, wherein the second cylinder head is provided in the first cylinder head.   The adjustment member which is provided between the first cylinder head and the second cylinder head and defines a relative position of the second cylinder head with respect to the first cylinder head is further provided. Fluid pressure cylinder.