Symmetrical seal HB

Description

The HB is a single-acting hydraulic sealing element made up of a compact polyurethane U-seal and an elastomer O-Ring acting as a energizing element. It is suitable for both rod and piston. Its rectangular cross-section provides stability in the housing, even in long strokes and high pressure. Thanks to the O-Ring it keeps the contact force at zero or low pressure preventing bypass, and as pressure rises the sealing force increases and the O-Ring ensures full lip actuation

Assembly

Lubricate the seal and the mating surfaces. Chamfer and polish the lead-in edges. Avoid burrs and sharp edges. Fit without twisting or pinching. Check correct seating before commissioning. Do not fit two seals back to back in a double-acting piston, to avoid pressure being trapped between them.

Advantages

Materials

Polyurethane (PU) U-seal for its high resistance to wear and extrusion, with an NBR (nitrile) preloading O-Ring. Suitable for mineral hydraulic oils, bio oils and water-based fluids (water soluble and water glycol) through the appropriate material selection.

Technical data

ALP NO	Ød	ØD	b	B	C
U-19.0525.46.35 HB	19.05	25.4	6.35	6.98	3
U-22.2328.583.18 HB	22.23	28.58	3.18	3.51	3
U-25.431.756.35 HB	25.4	31.75	6.35	6.98	3
U-25.434.934.76 HB	25.4	34.93	4.76	5.28	4
U-25.434.937.94 HB	25.4	34.93	7.94	8.71	4
U-25.438.16.35 HB	25.4	38.1	6.35	6.98	4.5
U-28.5838.14.76 HB	28.58	38.1	4.76	5.28	4
U-28409 HB	28	40	9	10	4
U-30406 HB	30	40	6	7	4
U-30409 HB	30	40	9	10	4
U-31.7538.16.35 HB	31.75	38.1	6.35	6.98	3
U-31.7541.287.94 HB	31.75	41.28	7.94	8.71	4
U-38.147.637.94 HB	38.1	47.63	7.94	8.71	4
U-38.147.639.53 HB	38.1	47.63	9.53	10.49	4
U-38.150.89.53 HB	38.1	50.8	9.53	10.49	4.5
U-40506 HB	40	50	6	7	4
U-44.4553.989.53 HB	44.45	53.98	9.53	10.49	4
U-47.6257.159.52 HB	47.62	57.15	9.52	10.48	4
U-50.860.339.53 HB	50.8	60.33	9.53	10.49	4
U-50.863.59.53 HB	50.8	63.5	9.53	10.49	4.5
U-57.1569.856.35 HB	57.15	69.85	6.35	6.98	4.5
U-63.576.29.53 HB	63.5	76.2	9.53	10.49	4.5
U-76.288.99.53 HB	76.2	88.9	9.53	10.49	4.5
U-76.295.2515.875 HB	76.2	95.25	15.875	17.47	5
U-88.9101.69.53 HB	88.9	101.6	9.53	10.49	4.5
U-92.08101.69.53 HB	92.08	101.6	9.53	10.49	4
U-1051209 HB	105	120	9	10	4.5
U-107.9512715.88 HB	107.95	127	15.88	17.47	5
U-10912510.5 HB	109	125	10.5	11.5	4.5
U-152.4171.4515.875 HB	152.4	171.45	15.875	17.47	5

Technical drawing and installation parameters of the HB symmetrical seals

This technical drawing defines the dimensions and geometric variables required for the correct selection and snap-on installation of the HB symmetrical seal, energized by an O-ring and suitable for both rod and piston. It shows the critical dimensions linked to the specification tables, such as the inside diameter (Ød), the outside diameter (ØD), the seal cross-section width (b), the housing groove width (B) and the lead-in chamfer length (C), together with the groove root fillet radii and the 20° lead-in angle. Working to these dimensions ensures accurate positioning, installation without distorting the profile and optimum static and dynamic sealing performance in double-acting applications at medium and high pressures.

Three-dimensional view and components of the HB symmetrical seals

This 3D illustration shows the basic structure of the HB symmetrical seal in detail. You can clearly see its two key elements: the polyurethane body with symmetrical sealing lips and the energizing O-ring, which provides the permanent radial load. Its compact design and reversible geometry allow it to be used either as a rod seal or as a piston seal, providing effective sealing and simple snap-on installation.

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