Rod seal HRO

Description

The HRO is a compact single-acting hydraulic rod seal made up of two parts: a PTFE profile ring acting as the main sealing element and an elastomer O-ring that pre-loads it against the rod. It stands out for its low friction, stick-slip-free operation and low housing height, making it ideal for the low and medium pressure range.

Assembly

Fit the HRO into a closed groove according to the drawing dimensions. Chamfer and round off the groove edges and carefully clean the housing before assembly. Do not drag the seal over sharp edges or threads, and lubricate the rod and the seal with the working fluid itself before insertion.

Advantages

Materials

The profile ring is made of high-performance PTFE (bronze-filled to improve extrusion resistance and thermal conductivity) and the pre-loading O-ring can be supplied in NBR or FKM depending on the fluid and working temperature. The PTFE+NBR combination, with a 70 Shore A O-ring, suits mineral hydraulic oils HL and HLP, greases and water-glycol within their ranges. The PTFE+FKM combination offers higher thermal and chemical resistance, suitable for higher temperatures and for HFD fluids. Other material combinations available on request.

Technical data

NO.	Ø d	Ø D	B
U-7112 HRO	7	11	2
U-9132 HRO	9	13	2
U-10142 HRO	10	14	2
U-12162 HRO	12	16	2
U-14182 HRO	14	18	2
U-16222.85 HRO	16	22	2.85
U-18242.85 HRO	18	24	2.85
U-20262.85 HRO	20	26	2.85
U-22282.85 HRO	22	28	2.85
U-25312.85 HRO	25	31	2.85
U-2835.53.8 HRO	28	35.5	3.8
U-3037.53.8 HRO	30	37.5	3.8
U-3239.53.8 HRO	32	39.5	3.8
U-3542.53.8 HRO	35	42.5	3.8
U-3643.53.8 HRO	36	43.5	3.8
U-4047.53.8 HRO	40	47.5	3.8
U-4249.53.8 HRO	42	49.5	3.8
U-4552.53.8 HRO	45	52.5	3.8
U-5062.55.6 HRO	50	62.5	5.6
U-5567.55.6 HRO	55	67.5	5.6
U-6072.55.6 HRO	60	72.5	5.6
U-6375.55.6 HRO	63	75.5	5.6
U-6577.55.6 HRO	65	77.5	5.6
U-7082.55.6 HRO	70	82.5	5.6
U-7587.55.6 HRO	75	87.5	5.6
U-8092.55.6 HRO	80	92.5	5.6
U-8597.55.6 HRO	85	97.5	5.6
U-90102.55.6 HRO	90	102.5	5.6
U-92104.55.6 HRO	92	104.5	5.6
U-100112.55.6 HRO	100	112.5	5.6
U-105117.55.6 HRO	105	117.5	5.6
U-110122.55.6 HRO	110	122.5	5.6
U-115127.55.6 HRO	115	127.5	5.6
U-120132.55.6 HRO	120	132.5	5.6
U-125137.55.6 HRO	125	137.5	5.6
U-1301457.55 HRO	130	145	7.55
U-1401557.55 HRO	140	155	7.55
U-1501657.55 HRO	150	165	7.55
U-1601757.55 HRO	160	175	7.55
U-2002157.55 HRO	200	215	7.55

Technical drawing and installation parameters of the HRO rod seals

This technical drawing defines the essential dimensions and geometric variables for the correct housing and installation of the HRO rod seal. It specifies the critical dimensions linked to the data tables, including the groove width (B), the rod diameter (Ød) and the housing bore diameter (ØD). It also details the groove edge radii (R1 and R ≤ 0.3), the extrusion gap (e) and the 15° angle of the lead-in chamfer, which must be rounded and free of burrs. These values make the most of the profile’s low housing height, ensure the correct assembly of the sliding ring together with the pre-loading O-Ring and prevent damage to the ring during installation.

Three-dimensional view and components of the HRO rod seals

This 3D illustration details the basic structure of the HRO single-acting rod seal for hydraulic applications. The drawing clearly shows its two elements: the high-performance bronze-filled PTFE profile ring, which improves extrusion resistance and thermal conductivity, and the elastomer O-Ring in NBR or FKM, which preloads it against the rod. Its compact design, with a low housing height, offers low friction, stick-slip free operation and a long service life with low heat generation in the low and medium pressure range.

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