Rod packing
In one surface of a ring member, a plurality of incision grooves incised in a radial direction from an inner peripheral edge up to an appropriate position and those incised from an outer peripheral edge to an appropriate position are alternately formed, and in the other surface, incision grooves continuing from the inner peripheral edge up to the outer peripheral edge are formed. In order to adapt to the expansion and the contraction due to a temperature change and a change in shape and dimension due to abrasion, the inner incision grooves and the outer incision grooves increase/decrease in width, causing the packing to expand/contract in the circumferential direction, so that the packing is capable of maintaining its contact state with a shaft to minimize the leakage of the fluid.
1. A resin-made rod packing in a ring shape which is disposed at a shaft seal part of a shaft made of metal while housed in a packing case, the rod packing comprising a ring member forming the ring shape,
wherein the ring member includes:
a plurality of inner incision grooves which are arranged in a circumferential direction in an axial-direction of a first surface of the ring member and which each extend in a radial direction from an inner peripheral surface of an inner diameter of the ring member toward an outer peripheral surface of an outer diameter of the ring member, the inner incision groove having a depth in the radial direction;
a plurality of outer incision grooves which are arranged in the circumferential direction in the axial-direction of the first surface of the ring member and which each extend in the radial direction from an outer peripheral surface of an outer diameter of the ring member toward the inner peripheral surface of the inner diameter of the ring member, the outer incision groove having a depth in the radial direction; and
a plurality of inner-to-outer incision grooves which are formed in an axial-direction of a second surface of the ring member and extend in the radial direction from the inner peripheral surface of the inner diameter of the ring member toward the outer peripheral surface of the outer diameter of the ring member, the second surface being opposite to the first surface in the axial-direction, and the inner-to-outer incision groove having a depth in the radial direction;
the inner incision groove does not extend through the outer peripheral surface; and
the outer incision groove does not extend through the inner peripheral surface.
2. The rod packing according to claim 1 , wherein a pair of the inner incision grooves and a pair of the outer incision grooves are alternately arranged, and in each of spaces between the pair of inner incision grooves and between the pair of outer incision grooves, the inner-to-outer incision groove is disposed.
3. The rod packing according to claim 1 or 2 , wherein the inner-to-outer incision grooves face a high-pressure side.
4. The rod packing according to any one of claims 1 to 3 ,
wherein in outer peripheral surface, a biasing member holding groove is formed along the circumferential direction, and
wherein a biasing member is disposed in the biasing member holding groove to bias the inner peripheral surface in such a direction as to press the inner peripheral surface against the shaft.