JP2012202446A5 - - Google Patents

Description

The present invention is a fluid pressure cylinder cushion mechanism that decelerates a piston rod in the vicinity of the stroke end of the piston rod with respect to the cylinder tube, and a cushion gap that restricts a flow of working fluid by an outer periphery of a cushion bearing provided on the piston rod, A bypass passage that is provided in a cushion gap defining member that defines a cushion gap between the cushion bearing and the outer periphery of the cushion bearing, and that guides hydraulic oil that bypasses the cushion gap, and a bypass opening area of the bypass passage that is provided in the cushion gap defining member. A bypass diaphragm adjusting mechanism for adjusting. The bypass throttle adjusting mechanism includes a valve housing hole in which the bypass passage is opened, a spool that is housed in the valve housing hole to increase or decrease the passage opening area of the bypass passage, a set screw that supports the spool, and a screw that engages the set screw. And a screw hole for adjustment .

According to the present invention, by adjusting the screwing position of the set screw with respect to the adjusting screw hole , the spool is displaced by the valve housing hole, and the passage opening area of the bypass passage can be changed. By adjusting the cushion pressure in this way, the excess or deficiency of the cushion pressure due to the dimensional variation of the members that define the cushion gap is eliminated.

1 is a cross-sectional view of a hydraulic cylinder showing an embodiment of the present invention. Similarly, sectional drawing of the hydraulic cylinder which expanded a part of FIG. The figure which similarly shows operation | movement of a bypass aperture adjustment mechanism. Sectional view of the hydraulic cylinder showing another embodiment. Similarly, sectional drawing of the hydraulic cylinder which expanded a part of FIG. The figure which similarly shows operation | movement of a bypass aperture adjustment mechanism.

The bypass passage 50 is defined by through holes 51 and 52 and a notch 48 formed in the cylinder head 40 provided as a cushion gap defining member . The through holes 51 and 52 are formed to extend on a straight line parallel to the central axis O. One end of the through hole 51 opens to the supply / discharge port 43, and one end of the through hole 52 opens to the rod chamber 2 through the notch 48. Thereby, the bypass passage 50 communicates the supply / exhaust port 43 and the rod chamber 2.

The bypass throttle adjusting mechanism 65 includes a valve accommodating hole 53 that intersects with the through hole 51 of the bypass passage 50, a spool 64 that is accommodated in the valve accommodating hole 53 and has a variable passage opening area of the bypass passage 50, and the cylinder head 40. A set screw 63 for supporting the spool 64 and an adjustment screw hole 54 for screwing the set screw 63 are provided. The set screw 63 is configured such that the screwing position with respect to the adjustment screw hole 54 is adjusted by an operator.

The valve housing hole 53 is formed so as to extend on a straight line substantially orthogonal to the central axis O, and is also substantially orthogonal to the through hole 51 of the bypass passage 50. The adjustment screw hole 54 is formed coaxially with the valve housing hole 53.

A working hole (screw hole) 55 is formed in the cylinder head 40 coaxially with the adjustment screw hole 54. This working hole 55 opens in the outer wall surface of the cylinder head 40, and the stopper 74 is attached. The plug 74 is screwed into the work hole 55 and is attached to the valve hole 53 so that the hydraulic oil does not leak out through the valve hole 53.

The set screw 63 has a head portion 72 that is screwed into the adjusting screw hole 54 and a shaft portion 70 that is in contact with the end face 64 a of the spool 64. A male screw that is screwed into the adjustment screw hole 54 is formed on the outer periphery of the head portion 72, and a tool engaging portion 71 that engages with a tool is opened on the end surface of the head portion 72. For example, the tool engaging portion 71 is a hexagonal hole, and a hexagon wrench is used as a tool that engages with the tool engaging portion 71.

As described above, in the present embodiment, the cushion mechanism 6 of the fluid pressure cylinder 1 that decelerates the piston rod 30 in the vicinity of the stroke end of the piston rod 30 with respect to the cylinder tube 10, and the cushion gap 8 that restricts the flow of the working fluid; A bypass passage 50 that guides hydraulic oil that bypasses the cushion gap 8, a valve accommodation hole 53 that opens the bypass passage 50, and a spool 64 that is accommodated in the valve accommodation hole 53 and increases or decreases the passage opening area of the bypass passage 50. And a set screw 63 that supports the spool 64 and an adjustment screw hole 54 into which the set screw 63 is screwed.

Based on the above configuration, by adjusting the screwing position of the set screw 63 with respect to the adjustment screw hole 54, the spool 64 is displaced in the valve housing hole 53, and the passage opening area of the bypass passage 50 is changed. As a result, the cushion pressure is adjusted by changing the resistance applied to the working fluid flowing through the bypass passage 50, so that the excess or deficiency of the cushion pressure due to the dimensional variation of the members defining the cushion gap 8 is eliminated. The As a result, the variation in cushioning performance can be suppressed without increasing the dimensional accuracy of the members that define the cushion gap 8, thereby reducing the cost of the product.

A bypass passage 28 is provided in a holder 23 provided as a cushion gap defining member . The bypass passage 28 is defined by a notch 25 formed in the holder 23 , through holes 26 and 27, and a notch 29. The through holes 26 and 27 are formed to extend on a straight line parallel to the central axis O. One end of the through hole 26 opens into the supply / discharge passage 5 through the notch 25, and one end of the through hole 27 opens into the rod chamber 2 through the notch 29. As a result, the bypass passage 28 communicates the supply / exhaust port 43 and the rod chamber 2 via the supply / discharge passage 5.

During the contraction operation of the hydraulic cylinder 1, the hydraulic oil in the rod chamber 2 flows through the cushion gap 8 and through the bypass passage 28 to the supply / discharge passage 5 as indicated by arrows in FIG. 5 .

As shown in FIG. 5, the bypass throttle adjusting mechanism 65 has a valve housing hole 33 that intersects the through hole 51 of the bypass passage 50, and is accommodated in the valve housing hole 33 so that the passage opening area of the bypass passage 28 is variable. A spool 64, a set screw 63 that supports the spool 64 with respect to the holder 23, and an adjustment screw hole 34 into which the set screw 63 is screwed are provided. The set screw 63 is configured such that the screwing position with respect to the adjustment screw hole 34 is adjusted by an operator.

In the holder 23, the valve accommodation hole 33 is formed so as to extend on a straight line substantially orthogonal to the central axis O, and an adjustment screw hole 34 is formed coaxially with the valve accommodation hole 33.

A working hole (screw hole) 55 is formed in the cylinder tube 10 coaxially with the adjustment screw hole 34. One end of the work hole 55 faces the adjustment screw hole 34 of the holder 23, the other end opens on the outer wall surface of the cylinder tube 10, and the plug 74 is attached.

1 Hydraulic cylinder (fluid pressure cylinder)
5 Supply / exhaust passage 6 Cushion mechanism 8 Cushion gap 10 Cylinder tube 23 Holder ( cushion gap defining member )
28, 50 Bypass passages 33, 53 Valve housing holes 34, 54 Adjustment screw hole 55 Work hole 30 Piston rod 40 Cylinder head ( cushion gap defining member )
43 Supply / exhaust port 60 Cushion bearing 61 Bearing outer peripheral surface 63 Set screw 64 Spool 65 Bypass throttle adjustment mechanism 66 Spring

Claims (3)

A fluid pressure cylinder cushion mechanism that decelerates the piston rod near the stroke end of the piston rod relative to the cylinder tube,
A cushion gap that restricts the flow of working fluid by the outer periphery of a cushion bearing provided on the piston rod ;
A bypass passage that is provided in a cushion gap defining member that defines the cushion gap between the outer periphery of the cushion bearing and guides hydraulic oil that bypasses the cushion gap;
A bypass throttle adjusting mechanism that is provided in the cushion gap defining member and adjusts a passage opening area of the bypass passage;
The bypass throttle adjusting mechanism is
A valve accommodating hole in which the bypass passage is opened,
A spool to increase or decrease the passage opening area of the bypass passage is accommodated in the valve accommodating hole,
A set screw for supporting the spool,
A fluid pressure cylinder cushion mechanism comprising: an adjustment screw hole into which the set screw is screwed. The fluid pressure cylinder cushion mechanism according to claim 1,
A holder interposed inside the cylinder tube;
It said bypass throttle adjusting mechanism interposed by Ru flow body pressure cylinder cushion mechanism together with the bypass passage is formed in the holder. A cushion mechanism for a fluid pressure cylinder according to claim 2,
The cushion gap image made is Ru flow body pressure cylinder cushion mechanism by the inner peripheral surface of the holder.