JP5684166B2 - Fluid pressure cylinder - Google Patents

Description

  The present invention relates to a fluid pressure cylinder equipped with a cushion mechanism.

  As a fluid pressure cylinder, the thing of patent document 1 is mentioned, for example. This fluid pressure cylinder is configured by mounting a cushion mechanism near the stroke end of the piston rod. The cushion mechanism includes a vent hole communicating with the cylinder air chamber in the cylinder tube, a cushion air chamber formed near the stroke end and communicating with the vent hole, and a cushion packing provided on a peripheral surface of the cushion air chamber. And a cushion ring integral with the piston. Furthermore, in the cushion mechanism of Patent Document 1, a cushion valve and a check valve are provided in the vent hole.

  When the cushion mechanism is inserted into the cushion packing near the stroke end, the air in the cylinder air chamber is restricted from flowing into the cushion air chamber by the cushion packing. The air in the cylinder air chamber, which is restricted from flowing into the cushion air chamber, gradually flows into the cushion air chamber while passing through the gap of the cushion valve. At this time, the check valve is closed by the air flow and the cushion valve is in a throttled state, so that the moving speed of the piston rod when reaching the stroke end is reduced.

  In this way, in the fluid pressure cylinder of Patent Document 1, an impact when the piston rod reaches the stroke end is buffered.

Japanese Utility Model Publication No. 6-51507

  However, in such a fluid pressure cylinder, not only the cushion packing has a certain diameter, but also the cushion ring fitted into the cushion packing is attached to the piston rod. It is thicker than that. Thus, in order to mount the cushion mechanism, it is necessary to secure a margin for incorporating these cushion packing and cushion ring in the cylinder tube between the cylinder tube and the piston rod. For this reason, when trying to mount a cushion mechanism on a small bore cylinder with a small diameter difference between the piston rod and the cylinder tube, the piston rod is made narrower as a result of securing a margin for incorporating the cushion packing and cushion ring in the cylinder. Processing is required.

  The present invention has been made in view of such conventional circumstances, and an object thereof is to provide a fluid pressure cylinder capable of mounting a cushion mechanism without being limited by the diameter of the cylinder tube.

In order to achieve the above object, a first aspect of the present invention provides a cylinder tube in which a supply / discharge port for supplying and discharging a fluid is formed, a piston movably accommodated in the cylinder tube, and the piston integrally. A fluid pressure cylinder equipped with a cushion mechanism that can move the piston rod when the fluid is supplied and discharged, and that cushions an impact when the piston rod reaches the stroke end. The cushion mechanism is provided on the same axis as the piston rod in the cylinder tube, and is movable on the same axis by the piston, and on the opposite side of the piston in the movable body in the cylinder tube. And a fluid chamber capable of storing the fluid, and a discharge capable of discharging the fluid stored in the fluid chamber. When, it is configured to include a by the movable body moves in the said fluid chamber side of the piston is configured to reduce the volume of the fluid chamber, wherein the movable body, the fluid chamber A large diameter portion is formed on the side facing the piston, and a small diameter portion is formed on the side facing the piston, and the area of the surface facing the fluid chamber in the large diameter portion is equal to The gist is that it is set larger than the area of the opposing surface .

  According to a second aspect of the present invention, in the fluid pressure cylinder according to the first aspect, the fluid chamber passes through the supply / discharge port and the discharge hole when the piston is moved to the side opposite to the fluid chamber side. The gist is that it is configured to communicate.

  According to a third aspect of the present invention, in the fluid pressure cylinder according to the second aspect, a throttle valve capable of adjusting a flow rate of the fluid discharged from the discharge hole is provided on the discharge hole. The gist.

According to a fourth aspect of the present invention, in the fluid pressure cylinder according to any one of the first to third aspects, the cushion mechanism is provided at each of both ends in the cylinder tube, and the cylinder The gist is that a large-diameter accommodating portion in which the fluid chamber is formed and a small-diameter accommodating portion in which the piston is accommodated are formed in the tube .
According to a fifth aspect of the present invention, in the fluid pressure cylinder according to any one of the first to fourth aspects, the diameter of the surface facing the piston in the small diameter portion is the same as the diameter of the piston. It is set as the gist.

  According to the present invention, the cushion mechanism can be mounted without being limited by the diameter of the cylinder tube.

(A) is sectional drawing which shows the fluid pressure cylinder in an immersion position, (b) is sectional drawing which shows the fluid pressure cylinder in a protrusion position. (A)-(c) is sectional drawing which shows the movement from an immersion position to a protrusion position. (A)-(c) is sectional drawing which shows the movement from a protrusion position to an immersion position. Sectional drawing which shows the fluid pressure cylinder in another example.

An embodiment of the present invention will be described below with reference to FIGS.
As shown in FIGS. 1 (a) and 1 (b), the fluid pressure cylinder of this embodiment has a shell formed by a cylinder tube 10. The cylinder tube 10 includes a first and a second connected to a supply / discharge device that supplies a fluid (compressed air in this embodiment) and discharges the fluid to the outside (in the present embodiment, the atmosphere). Supply / discharge ports P1 and P2 are formed. These supply / discharge ports P1 and P2 are configured to communicate with the outside of the cylinder tube 10, that is, in the atmosphere. These supply / discharge ports P1 and P2 communicate with respective passages T1, T2, T3, and T4 (described later) communicating with respective pressure chambers (21, 22, 23, and 24) described later capable of storing fluid. Each of the supply / discharge ports P1 and P2 is formed so as to be separated from the axial center of the cylinder tube 10 to different end sides in the axial direction.

  Then, by supplying and discharging the fluid, the position of the piston rod 13 accommodated in the cylinder tube 10 is switched and controlled. In the following description, the position where the piston rod 13 is immersed in the cylinder tube 10 as shown in FIG. 1A is referred to as “immersion position”, and the piston rod 13 is removed from the cylinder tube 10 as shown in FIG. The protruding position is called “protruding position”.

  An accommodation hole 11 that can accommodate various components is formed inside the cylinder tube 10. In the accommodation hole 11, a cylindrical rod cover 12a is disposed on the first supply / discharge port P1 side, and a disc-shaped head cover 12b is disposed on the second supply / discharge port P2 side. Moreover, in the accommodation hole 11, while the rod cover 12a side is opened, the head cover 12b side is sealed.

Further, a large-diameter accommodating portion 11a and a small-diameter accommodating portion 11b are formed in the accommodating hole 11 in order from the covers 12a and 12b toward the center. In the housing hole 11, the inner diameter (cylinder bore) of the large-diameter housing portion 11a is set larger than the inner diameter (cylinder bore) of the small-diameter housing portion 11b.

  The accommodation hole 11 accommodates a piston 14 that is movable along the axial direction of the cylinder tube 10 by a fluid pressure based on the fluid supplied and discharged from each of the supply / discharge ports P1 and P2. An integral rod-shaped piston rod 13 is inserted.

In addition, packings 15 (two in this embodiment) are mounted on the outer peripheral surface of the piston 14 to seal between the outer peripheral surface and the inner peripheral surface of the receiving hole 11 (small-diameter receiving portion 11b).
The accommodation hole 11 accommodates first and second buffering pistons 16 and 19 as moving bodies that can move along the axial direction of the cylinder tube 10 by the movement of the piston 14. The first buffering piston 16 is accommodated on the first supply / exhaust port P1 side with the piston 14 as a boundary, while the second buffering piston 19 is on the second supply / exhaust port P2 side with the piston 14 as a boundary. Contained.

  Specifically, the piston rod 13 is inserted into the first buffering piston 16, and the first buffering piston 16 is accommodated on the same axis as the piston rod 13 between the rod cover 12a and the piston 14. Yes. The first buffering piston 16 is movable along the piston rod 13. The first buffer piston 16 is formed with a large diameter portion 16a and a small diameter portion 16b in order from the rod cover 12a side. In the first buffer piston 16, the outer diameter of the large diameter portion 16a is set larger than the outer diameter of the small diameter portion 16b, and the area of the surface of the large diameter portion 16a that faces the rod cover 12a is the piston of the small diameter portion 16b. 14 is set to be larger than the area of the surface facing 14.

  In the first buffer piston 16, the outer peripheral surfaces of the large diameter portion 16a and the small diameter portion 16b are between the outer peripheral surface and the inner peripheral surface of the accommodation hole 11 (the large diameter accommodation portion 11a or the small diameter accommodation portion 11b). Packing 17 (in this embodiment, two places) is attached. Further, in the first buffer piston 16, a packing 18 (one place in the present embodiment) that seals the space between the piston rod 13 and the outer peripheral surface is mounted on the inner peripheral surface of the large diameter portion 16a.

  When such a first buffering piston 16 moves from the rod cover 12a side toward the head cover 12b side, since the large diameter portion 16a cannot enter the small diameter accommodating portion 11b, further movement is restricted. . Thereby, as shown in FIG. 1A, the first buffering piston 16 is movable in the range of the stroke d1 between the rod cover 12a and the first buffering piston 16.

  The second buffering piston 19 is accommodated on the same axis as the piston rod 13 between the head cover 12 b and the piston 14. The second buffer piston 19 is formed with a large diameter portion 19a and a small diameter portion 19b in order from the head cover 12b side. In the second buffer piston 19, the outer diameter of the large diameter portion 19a is set larger than the outer diameter of the small diameter portion 19b, and the area of the surface of the large diameter portion 19a facing the head cover 12b is the piston 14 of the small diameter portion 19b. Is set to be larger than the area of the surface facing the.

  Further, in the second buffer piston 19, the outer peripheral surfaces of the large diameter portion 19a and the small diameter portion 19b are between the outer peripheral surface and the inner peripheral surface of the accommodation hole 11 (the large diameter accommodation portion 11a or the small diameter accommodation portion 11b). A packing 20 (in this embodiment, two places) is attached.

  When the second shock absorbing piston 19 moves from the head cover 12b side toward the rod cover 12a side, the large diameter portion 19a cannot enter the small diameter accommodating portion 11b, and thus further movement is restricted. . Thereby, as shown in FIG. 1B, the second buffering piston 19 is movable in the range of the stroke d2 between the head cover 12b and the second buffering piston 19.

  The piston 14, the first buffering piston 16, and the second buffering piston 19 divide the cylinder tube 10 into pressure chambers 21, 22, 23, and 24. Specifically, a first driving pressure chamber 21 is defined between the wall surface of the piston 14 on the rod cover 12a side and the wall surface of the first buffering piston 16 on the head cover 12b side. A second driving pressure chamber 22 is defined between the wall surface of the piston 14 on the head cover 12 b side and the wall surface of the second buffering piston 19 on the rod cover 12 a side. Further, between the wall surface of the first buffering piston 16 on the rod cover 12a side and the inner wall of the rod cover 12a, that is, on the opposite side of the piston 14 of the first buffering piston 16, is a first buffering fluid chamber. A pressure chamber 23 is defined. A second buffer pressure chamber as a fluid chamber is provided between the wall surface of the second buffer piston 19 on the head cover 12b side and the inner wall of the head cover 12b, that is, on the opposite side of the piston 14 of the second buffer piston 19. 24 is defined.

  The first driving pressure chamber 21 and the second driving pressure chamber 22 are elastically sealed by the packing 15 of the piston 14. The first drive pressure chamber 21 and the first buffer pressure chamber 23 are elastically sealed by packings 17 and 18 of the first buffer piston 16. The second driving pressure chamber 22 and the second buffering pressure chamber 24 are elastically sealed by the packing 20 of the second buffering piston 19. That is, each of these pressure chambers 21, 22, 23, and 24 is configured to be able to store (fill) a fluid.

  The cylinder tube 10 is formed with a first air passage T1 having one end communicating with the first supply / discharge port P1, and the other end of the first air passage T1 communicates with the first drive pressure chamber 21. doing. As a result, in the first driving pressure chamber 21, fluid is supplied and discharged by the first supply / discharge port P1.

  Further, the cylinder tube 10 is formed with a first buffering air passage T2 as a discharge hole whose one end communicates with the first supply / discharge port P1, and the other end of the first buffering air passage T2 is a second one. It communicates with the one buffer pressure chamber 23. A first throttle valve V1 is disposed on the first buffering air passage T2. As a result, in the first buffer pressure chamber 23, the fluid is supplied and discharged through the first supply / discharge port P1 while the flow rate is adjusted by the first throttle valve V1.

  The cylinder tube 10 is formed with a second air passage T3 having one end communicating with the second supply / discharge port P2, and the other end of the second air passage T3 communicates with the second driving pressure chamber 22. doing. Thus, in the second driving pressure chamber 22, the fluid is supplied and discharged by the second supply / discharge port P2.

  Further, the cylinder tube 10 is formed with a second buffering air passage T4 as a discharge hole whose one end communicates with the second supply / discharge port P2, and the other end of the second buffering air passage T4 is a second one. It communicates with the two buffer pressure chambers 24. A second throttle valve V2 is disposed on the second buffering air passage T4. Thus, in the second buffer pressure chamber 24, the fluid is supplied and discharged by the second supply / discharge port P2 in a state where the flow rate is adjusted by the second throttle valve V2.

  The cylinder tube 10 includes a first breathing air passage serving as a breathing hole for a pressure chamber defined on the head cover 12b side of the large diameter portion 16a when the first buffering piston 16 moves to the rod cover 12a side. T5 is formed. The first breathing air passage T5 communicates with the atmosphere, and inhales (supplys) the atmosphere when the first buffering piston 16 moves toward the rod cover 12a. When the head cover 12b is moved, the sucked air is exhausted. The cylinder tube 10 also has a second breathing air passage serving as a breathing hole for a pressure chamber defined on the rod cover 12a side of the large diameter portion 19a when the second buffering piston 19 moves to the head cover 12b side. T6 is formed. The second breathing air passage T6 communicates with the atmosphere, and inhales (supplys) the atmosphere when the second buffering piston 19 moves toward the head cover 12b, and the rod of the second buffering piston 19 When the air is moved to the cover 12a side, the intake air is exhausted.

  Then, when the piston rod 13 is moved by supplying / discharging the fluid from the supply / discharge ports P1, P2, the volumes of the drive pressure chambers 21, 22 are displaced between the maximum volume and the minimum volume. When the buffer pistons 16 and 19 are moved by the piston 14 of the piston rod 13 thus moved, the volumes of the buffer pressure chambers 23 and 24 are displaced between the maximum volume and the minimum volume. In the immersion position, the first driving pressure chamber 21 and the first buffering pressure chamber 23 are displaced to the maximum volume, while the second driving pressure chamber 22 and the second buffering pressure chamber 24 are set to the minimum volume. Displace. In the protruding position, the second driving pressure chamber 22 and the second buffering pressure chamber 24 are displaced to the maximum volume, while the first driving pressure chamber 21 and the first buffering pressure chamber 23 are set to the minimum volume. Displace.

  The piston rod 13 reciprocates between the immersion position and the protruding position as shown in FIGS. 2 (a) to 2 (c) and FIGS. 3 (a) to 3 (c). In FIGS. 2A to 2C and FIGS. 3A to 3C, solid arrows indicate supply / discharge of the air passages T1 and T3, and broken arrows indicate buffer air passages T2. , T4 means supply and discharge.

  As shown in FIG. 2A, in the immersion position, the first drive pressure chamber 21 and the first buffer pressure chamber 23 are filled and pressurized by supplying the fluid to the first supply / discharge port P1. It will be in the state. On the other hand, at the immersive position, the second drive pressure chamber 22 and the second buffer pressure chamber 24 are filled with air and decompressed by discharging the fluid from the second supply / discharge port P2 (substantially at atmospheric pressure). State). In this case, the second buffering pressure chamber 24 communicates with the atmosphere (outside of the cylinder tube 10) through the second buffering air passage T4.

  That is, in the immersion position, the piston 14 biases the second buffering piston 19 toward the head cover 12b due to the pressure difference between the first driving pressure chamber 21 and the second driving pressure chamber 22. Further, at the immersive position, the first buffering piston 16 is moved to a state where movement from the rod cover 12a side to the piston 14 side is restricted due to the pressure receiving area difference of the first buffering piston 16.

  When discharge of fluid from the first supply / discharge port P1 and supply of fluid to the second supply / discharge port P2 are started from this state, the first drive pressure chamber 21 and the first buffer pressure chamber 23 are filled. The discharged fluid is discharged and the fluid is supplied to the second driving pressure chamber 22 and the second buffering pressure chamber 24.

  In this case, as shown in FIG. 2B, the first driving pressure chamber 21 and the first buffering pressure chamber 23 are decompressed by the discharge of the fluid from the first supply / discharge port P1. In this case, the discharge from the first drive pressure chamber 21 is in a state where the atmosphere is filled and the pressure is reduced due to the discharge of the fluid (substantially at atmospheric pressure). Further, in this case, with respect to the discharge of the first buffer pressure chamber 23, the throttle discharge in which the flow rate of the fluid discharged is reduced by the first throttle valve V1 rather than the discharge of the first drive pressure chamber 21 is performed. For this reason, with respect to the pressure reduction of the first buffer pressure chamber 23, a throttling pressure reduction is performed in which the pressure is reduced over the time of the first driving pressure chamber 21. In this case, the first buffering pressure chamber 23 communicates with the atmosphere (outside the cylinder tube 10) through the first buffering air passage T2. On the other hand, as shown in FIG. 2B, the fluid is filled into the second drive pressure chamber 22 and the second buffer pressure chamber 24 and pressurized by supplying the fluid to the second supply / discharge port P2. It becomes a state.

  That is, in this case, the second buffering piston 19 is moved to a state in which the movement from the head cover 12b side to the piston 14 side is restricted due to the pressure receiving area difference of the second buffering piston 19. In this case, the piston 14 moves to the first buffering piston 16 side due to the pressure difference between the first driving pressure chamber 21 and the second driving pressure chamber 22. In such a movement, the piston near the stroke end of the movement from the immersion position is caused by the difference in pressure receiving area of the first buffering piston 16 and the pressure receiving area difference between the first driving pressure chamber 21 and the first buffering pressure chamber 23. 14 contacts the first buffer piston 16. In this case, the pressure in the first buffer pressure chamber 23 is higher than the pressure in the first drive pressure chamber 21 because it is accompanied by throttling.

  Furthermore, when the fluid discharge from the first supply / discharge port P1 and the fluid supply from the second supply / discharge port P2 are continued from this state, the fluid filled in the first buffer pressure chamber 23 is discharged, Fluid is supplied to the second drive pressure chamber 22 and the second buffer pressure chamber 24.

  In this case, as shown in FIG. 2 (c), the fluid is discharged from the first supply / discharge port P1 and the first throttle valve V1 is used to perform the throttle discharge with respect to the first buffer pressure chamber 23. The pressure in the first buffer pressure chamber 23 is reduced by throttling. On the other hand, as shown in FIG. 2 (c), by supplying the fluid to the second supply / discharge port P2, the second drive pressure chamber 22 and the second buffer pressure chamber 24 are filled and pressurized. It becomes a state.

  In other words, in this case, the piston 14 and the first buffering piston 16 are integrally integrated gradually by the pressure reduction of the first buffering pressure chamber 23 and the pressurization of the second driving pressure chamber 22 side. That is, it is in a state of moving to the first buffering pressure chamber 23 side. In such movement, the first buffer piston 16 reduces the volume of the first buffer pressure chamber 23. For this reason, in the first buffering pressure chamber 23, throttle pressure reduction and pressurization by reducing the volume thereof are performed. Such a movement is performed during the stroke d1 after the piston 14 contacts the first buffering piston 16, and as a result of the piston 14 reaching the stroke end, the piston 14 moves from the retracted position to the protruding position. Is completed.

  Subsequently, as shown in FIG. 3A, at the protruding position, the fluid is filled into the second drive pressure chamber 22 and the second buffer pressure chamber 24 by supplying the fluid to the second supply / discharge port P2. Pressure is applied. On the other hand, at the protruding position, the first drive pressure chamber 21 and the first buffering pressure chamber 23 are filled with the atmosphere and are reduced in pressure (substantially atmospheric pressure state) by the discharge of the first supply / discharge port P1. Become. In this case, the first buffering pressure chamber 23 communicates with the atmosphere (outside the cylinder tube 10) through the first buffering air passage T2.

  That is, at the protruding position, the piston 14 biases the first buffering piston 16 toward the rod cover 12a due to the pressure difference between the first driving pressure chamber 21 and the second driving pressure chamber 22. . Further, at the protruding position, the second buffering piston 19 is moved to a state in which movement from the head cover 12b side to the piston 14 side is restricted due to the pressure receiving area difference of the second buffering piston 19.

  When supply of fluid to the first supply / discharge port P1 and discharge of fluid from the second supply / discharge port P2 are started from this state, the fluid is supplied to the first drive pressure chamber 21 and the first buffer pressure chamber 23. While being supplied, the fluid filled in the second drive pressure chamber 22 and the second buffer pressure chamber 24 is discharged.

  In this case, as shown in FIG. 3B, the first drive pressure chamber 21 and the first buffer pressure chamber 23 are filled with fluid and pressurized by supplying the fluid to the first supply / discharge port P1. It will be in the state.

  On the other hand, as shown in FIG. 3B, the second drive pressure chamber 22 and the second buffer pressure chamber 24 are decompressed by the discharge of the fluid from the second supply / discharge port P2. In this case, the discharge from the second drive pressure chamber 22 is in a state where the atmosphere is filled and the pressure is reduced by discharging the fluid (substantially at atmospheric pressure). Further, in this case, with respect to the discharge of the second buffer pressure chamber 24, the throttle discharge in which the flow rate of the fluid discharged is reduced by the second throttle valve V2 rather than the discharge of the second drive pressure chamber 22 is performed. For this reason, with respect to the pressure reduction of the second buffer pressure chamber 24, a throttling pressure reduction is performed in which the pressure is reduced over the time of the second drive pressure chamber 22. In this case, the second buffering pressure chamber 24 communicates with the atmosphere (outside of the cylinder tube 10) through the second buffering air passage T4.

  That is, in this case, due to the pressure receiving area difference of the first buffering piston 16, the first buffering piston 16 is moved to a state where movement from the rod cover 12a side to the piston 14 side is restricted. . In this case, the piston 14 moves toward the second buffering piston 19 due to the pressure difference between the first driving pressure chamber 21 and the second driving pressure chamber 22. In such a movement, the piston near the stroke end of the movement from the protruding position is caused by the difference in pressure receiving area of the second buffering piston 19 and the pressure receiving area difference between the second driving pressure chamber 22 and the second buffering pressure chamber 24. 14 contacts the second buffer piston 19. In this case, the pressure in the second buffer pressure chamber 24 is higher than the pressure in the second drive pressure chamber 22 because it is accompanied by throttling.

  Further, when the supply of fluid to the first supply / discharge port P1 and the discharge of fluid from the second supply / discharge port P2 are continued from this state, the fluid is supplied to the first drive pressure chamber 21 and the first buffer pressure chamber 23. Is supplied, and the fluid filled in the second buffer pressure chamber 24 is discharged.

  In this case, as shown in FIG. 3C, by supplying the fluid to the first supply / discharge port P1, the first driving pressure chamber 21 and the first buffering pressure chamber 23 are filled and pressurized. It will be in the state. On the other hand, as shown in FIG. 3 (c), the discharge of the fluid from the second supply / discharge port P2 and the discharge of the second buffer pressure chamber 24 are performed by the second throttle valve V2, and the second discharge is performed. The pressure in the two buffer pressure chambers 24 is reduced by throttling.

  That is, in this case, the piston 14 and the second buffering piston 19 are gradually integrated with the head cover 12b side by the decompression of the second buffering pressure chamber 24 and the pressurization of the first driving pressure chamber 21. That is, the second buffering pressure chamber 24 is moved. In such movement, the second buffering piston 19 reduces the volume of the second buffering pressure chamber 24. For this reason, in the second buffer pressure chamber 24 in this case, the throttle pressure is reduced and the pressure is reduced by reducing the volume thereof. Such movement is performed during the stroke d2 after the piston 14 contacts the second buffering piston 19, and as a result of the piston 14 reaching the stroke end, the piston 14 moves from the protruding position to the immersive position. Is completed.

Hereinafter, the operation of the present embodiment will be described.
This embodiment is equipped with a cushion mechanism that cushions an impact when the piston rod 13 reaches the stroke end.

  That is, the cushion mechanism of the present embodiment has a structure in which the buffer pistons 16 and 19 are accommodated on the same axis as the piston rod 13 in the cylinder tube 10. Further, the cushion mechanism of the present embodiment has a structure in which the buffer pressure chambers 23 and 24 are formed on the opposite sides of the pistons 14 in the buffer pistons 16 and 19 in the cylinder tube 10. Further, the cushion mechanism of the present embodiment has a structure in which the buffer air passages T2 and T4 that can discharge the fluid stored in the buffer pressure chambers 23 and 24 are formed.

  Thereby, when the piston rod 13 moves from the immersive position to the protruding position, the first buffering piston 16 tends to move toward the first buffering pressure chamber 23 along with the movement. When the piston rod 13 moves from the protruding position to the immersive position, the second buffering piston 19 tends to move toward the second buffering pressure chamber 24 along with the movement. That is, the movement of the buffer pistons 16 and 19 toward the buffer pressure chambers 23 and 24 acts so as to reduce the volume of the buffer pressure chambers 23 and 24.

  Then, by reducing the volume of each buffer pressure chamber 23, 24, the pressure in each buffer pressure chamber 23, 24 is increased, and the moving speed of each buffer piston 16, 19 is adjusted to be reduced. That is, when the piston rod 13 moves from the immersive position to the protruding position, adjustment is made so that the moving speed of the piston rod 13 is decelerated during the stroke d1 after the piston 14 contacts the first buffering piston 16. Thus, the impact when the piston rod 13 reaches the protruding position (stroke end) is buffered. Further, when the piston rod 13 moves from the protruding position to the immersive position, adjustment is made so that the moving speed of the piston rod 13 is decelerated during the stroke d2 after the piston 14 contacts the second buffering piston 19. Thus, the impact when the piston rod 13 reaches the immersive position (stroke end) is buffered.

  Further, the fluid in the buffer pressure chambers 23, 24 is discharged from the buffer air passages T2, T4 as the pressure in the buffer pressure chambers 23, 24 increases. It is also suppressed that the increase prevents the buffer pistons 16 and 19 and the piston rod 13 from moving.

Further, the cushion mechanism of the present embodiment has a structure in which the buffer pressure chambers 23 and 24 are communicated with the supply / discharge ports P1 and P2 through the buffer air passages T2 and T4.
Thus, fluid is supplied to the buffer pressure chambers 23 and 24 from the supply / discharge ports P1 and P2 when the piston rod 13 is moved to the opposite side to the buffer pressure chambers 23 and 24 side. become. That is, the fluid supply to the first buffering pressure chamber 23 accompanying the movement from the protruding position to the immersion position is the opposite side of the first buffering piston 16 from the first buffering pressure chamber 23 side. It acts to move to a state where movement from the rod cover 12a side to the piston 14 side is restricted. The fluid supply to the second buffering pressure chamber 24 accompanying the movement from the immersion position to the projecting position is such that the second buffering piston 19 is on the opposite side of the second buffering pressure chamber 24 side. It acts to move to a state where the movement from the head cover 12b side to the piston 14 side is restricted.

Further, the cushion mechanism of the present embodiment has a structure in which the throttle valves V1 and V2 are provided on the buffer air passages T2 and T4.
As a result, the flow rate of the fluid discharged from the buffer air passages T2 and T4 is adjusted by the throttle valves V1 and V2. By adjusting the throttle valves V1 and V2, the change in the internal pressure of the buffer pressure chambers 23 and 24 can be adjusted. Therefore, when the piston rod 13 is moved to the buffer pressure chambers 23 and 24 side. The degree of deceleration of the moving speed can also be adjusted.

Further, the cushion mechanism of the present embodiment has a structure provided at each of both ends in the cylinder tube 10.
In other words, the first buffering piston 16, the first buffering pressure chamber 23, the first buffering air passage T2, and the first throttle valve V1 are configured to move from the immersion position to the protruding position. Thus, the impact when the piston rod 13 reaches the stroke end is buffered. Further, since the second buffering piston 19, the second buffering pressure chamber 24, the second buffering air passage T4, and the second throttle valve V2 are configured, the projecting position is moved to the immersive position. Thus, the impact when the piston rod 13 reaches the stroke end is buffered.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The movement of the buffer pistons 16 and 19 accompanying the movement of the piston 14 toward the buffer pressure chambers 23 and 24 acts to reduce the volume of the buffer pressure chambers 23 and 24. Then, by reducing the volume of each buffer pressure chamber 23, 24, the pressure in each buffer pressure chamber 23, 24 is increased and the moving speed of each buffer piston 16, 19 is reduced. The movement speed of the piston rod 13 is also reduced and the impact when the piston rod 13 reaches the stroke end can be buffered. Further, the fluid in the buffer pressure chambers 23, 24 is discharged from the buffer air passages T2, T4 as the pressure in the buffer pressure chambers 23, 24 increases. It is also suppressed that the increase prevents the buffer pistons 16 and 19 and the piston rod 13 from moving. As described above, the cushion mechanism can be mounted if there is enough room to accommodate the buffer pistons 16 and 19 on the same axis of the piston rod 13 in the cylinder tube 10, and the diameters of the cylinder tube 10 and the piston rod 13 can be mounted. You will not be caught by the difference. As a result, there is no need to make the piston rod 13 thinner even if the cylinder tube 10 has a smaller diameter, and the cushion mechanism can be mounted without being restricted by the diameter of the cylinder tube.

  (2) Fluid is supplied to the buffer pressure chambers 23 and 24 from the supply / discharge ports P1 and P2 when the piston 14 is moved to the opposite side of the buffer pressure chambers 23 and 24. Become. That is, the supply of fluid to the buffer pressure chambers 23 and 24 operates to move the buffer pistons 16 and 19 to the opposite side to the buffer pressure chambers 23 and 24 side. As a result, when the piston rods 13 are moved toward the buffer pressure chambers 23 and 24 due to the movement of the buffer pistons 16 and 19, the buffer pistons 16 and 19 are brought into a state where the movement speed can be reduced. 19 can be restored.

  (3) The flow rate of the fluid discharged from each buffer air passage T2, T4 is adjusted by each throttle valve V1, V2. The adjustment of the throttle valves V1 and V2 makes it possible to adjust the change in the pressure of the buffer pressure chambers 23 and 24. Therefore, the movement when the piston 14 is moved to the buffer pressure chambers 23 and 24 side. The speed reduction can be adjusted. As a result, the flow rate of the fluid discharged from each buffering air passage T2, T4 can be adjusted according to the load accompanying the movement of the piston rod 13, and when the piston rod 13 reaches the stroke end according to the load. Shock can be buffered.

  (4) The piston rod 13 can buffer an impact when the piston rod 13 reaches the stroke end for each reciprocation. As a result, it is possible to suitably meet the demand of buffering the impact when the piston rod 13 reaches the stroke end every time the piston rod 13 reciprocates.

  (5) The buffer pressure chambers 23 and 24 are defined so as to include the wall surfaces of the buffer pistons 16 and 19 on the opposite side of the piston 14. As a result, the movement of the buffer pistons 16 and 19 toward the buffer pressure chambers 23 and 24 effectively acts to reduce the volume of the buffer pressure chambers 23 and 24. The impact when the piston rod 13 reaches the stroke end can be effectively buffered.

In addition, this embodiment mentioned above can also be implemented with the following forms which changed this suitably.
-This embodiment is good also as a structure which provides 1st and 2nd speed controller SC1, SC2 which can adjust the flow volume of a fluid in detail rather than each throttle valve instead of each throttle valve V1, V2. As such a structure, for example, as shown in FIG. 4, the speed controllers SC1, SC2 and the joints AD1, AD2 respectively correspond to the buffer air passages T2, T4 and the supply / discharge ports P1, P2 respectively. Can be realized by external connection outside the cylinder tube 10.

  In the present embodiment, the throttle valves V1 and V2 and the joints AD1 and AD2 as shown in FIG. 4 are respectively connected to the buffer air passages T2 and T4 and the supply / discharge ports P1 and P2 respectively. 10 may be externally connected.

  -In this embodiment, it can also comprise without providing each throttle valve V1, V2. That is, in each of the buffer pressure chambers 23 and 24, the same effect as in the present embodiment can be obtained even when the fluid is not squeezed out.

-You may make it equip each throttle valve V1, V2 of this embodiment also with a check valve.
In the present embodiment, other members may be interposed between the buffer pressure chambers 23 and 24 and the buffer pistons 16 and 19. As a result, the moving speed of the piston rod 13 can be adjusted stepwise.

  In the fluid pressure cylinder shown in the present embodiment, when it is sufficient to cushion the impact at the time of movement of either the immersive position or the protruding position, the cylinder tube 10 is mounted only on the side in order to exert a buffering effect. It can also be.

  The buffer air passages T2 and T4 of the present embodiment may not be in communication with the supply / discharge ports P1 and P2, but may be in communication with the outside (in the atmosphere) through other configurations. The throttle valves V1 and V2 may be provided on such a passage.

  In the present embodiment, each of the buffer pistons 16 and 19 and each of the buffer pressure chambers 23 and 24 has a structure located near the stroke end of the piston rod 13, but is separated from the stroke end, for example, a cylinder It can also be realized by a structure located near the center of the tube 10.

  In the present embodiment, each of the pressure chambers 21, 22, 23, and 24 can achieve the same effects as in the present embodiment even in a substantially sealed state with a slight fluid leakage due to a slight clearance. That is, for example, a metal seal instead of an elastic seal can be adopted as a seal for each pressure chamber 21, 22, 23, 24.

  -In this embodiment, each buffer piston 16 and 19 is good also as a structure returned to the state by which the movement to each piston 14 side is controlled by elastic force, such as a spring, for example. In this case, a spring or the like is provided between each cover 12a, 12b and each buffer piston 16, 19.

The present embodiment can also be applied to a double rod type fluid pressure cylinder.
-In this embodiment, you may arrange | position the exclusive supply / discharge port for performing supply / discharge of the fluid in each buffer pressure chamber 23,24.

In the present embodiment, the fluid is not limited to air but may be any fluid as long as it is a compressed fluid.
Next, a technical idea that can be grasped from the above-described embodiment and another example (modification) will be additionally described below.

  (B) The fluid pressure cylinder according to any one of claims 1 to 4, wherein the fluid chamber includes a wall surface on the opposite side of the piston in the moving body.

  P1, P2: Supply / discharge port, T1, T3 ... Air passage, T2, T4 ... Buffer air passage, V1, V2 ... Throttle valve, 10 ... Cylinder tube, 13 ... Piston rod, 14 ... Piston, 16, 19 ... Buffer Piston for driving, 21, 22 ... driving pressure chamber, 23, 24 ... buffering pressure chamber.

Claims (5)

A cylinder tube having a supply / discharge port for supplying and discharging a fluid; a piston movably accommodated in the cylinder tube; and a piston rod integrated with the piston; and supplying and discharging the fluid. In the hydraulic cylinder equipped with a cushion mechanism that allows the piston rod to move and cushions an impact when the piston rod reaches the stroke end,
The cushion mechanism is
A movable body provided on the same axis of the piston rod in the cylinder tube and movable on the same axis by the piston;
A fluid chamber formed on the opposite side of the piston in the moving body in the cylinder tube and capable of storing the fluid;
A discharge hole capable of discharging the fluid stored in the fluid chamber, and
The volume of the fluid chamber is reduced by the moving body as the piston moves toward the fluid chamber .
The moving body has a large-diameter portion formed on the side facing the fluid chamber, a small-diameter portion formed on the side facing the piston, and an area of a surface of the large-diameter portion facing the fluid chamber. Is set to be larger than the area of the surface of the small-diameter portion facing the piston .   The fluid pressure cylinder according to claim 1, wherein the fluid chamber is configured to communicate with the supply / discharge port through the discharge hole when the piston is moved to the opposite side to the fluid chamber side.   The fluid pressure cylinder according to claim 2, wherein a throttle valve capable of adjusting a flow rate of the fluid discharged from the discharge hole is provided on the discharge hole. The cushion mechanism is provided at each end of the cylinder tube ,
The large diameter accommodating part in which the said fluid chamber is formed in the said cylinder tube, and the small diameter accommodating part in which the said piston is accommodated are formed as described in any one of Claims 1-3. Fluid pressure cylinder. The fluid pressure cylinder according to any one of claims 1 to 4, wherein a diameter of a surface facing the piston in the small diameter portion is set to be the same as a diameter of the piston.