NSK7907A5TYSULP4Super Precision Angular Contact Ball Bearing – Straight Bore, 35 mm ID, 55 mm OD, 10 mm Width, Open, 25° Contact Angle, Polyamide Cage, Light Preload, ABEC 7.

Product Description

What this part is

NSK 7907A5TYSULP4 super precision angular contact ball bearing, single row, 35 mm bore, 55 mm outside diameter, 10 mm width. Open on both faces, polyamide resin ball-guided cage, 25° contact angle, light preload, ISO Class 4 running accuracy. The carton also carries 3MM9307WI SUL and B-71907-E.

Decoding the designation

7 marks NSK’s standard-series high-accuracy angular contact range and 9 the 19 dimension series, the thin-section series. The bore number 07 multiplied by five gives the 35 mm bore. A5 is NSK’s code for a 25° contact angle, confirmed by the 3MM prefix on the Fafnir-scheme marking. TY is the polyamide resin ball-guided cage. SU is single row universal, L light preload and P4 ISO Class 4, equivalent to ABEC 7.

What these specs mean in practice

The 19 series is the slimmest angular contact section for a given bore, which suits compact spindle noses and instrument drives where axial space is short. A 25° contact angle gives more thrust capacity and axial stiffness than a 15° bearing, and this size accepts 7.20 kN of axial load. The polyamide ball-guided cage is light and quiet, and it is what supports 30000 rpm on oil against 22000 rpm on grease. Light preload of 110 N gives 93 N per micron of axial rigidity in a back-to-back or face-to-face pair, with a measured axial clearance of minus 3 microns.

Quantity and configuration

Single bearing. 1 Pc. Universal grinding means any two bearings from the range stack back-to-back, face-to-face or in tandem and come up to the ground preload with no shims.

Fitting notes

The shaft abutment diameter is 40 mm minimum and the housing abutment 50 mm maximum, with a second housing step of 52.5 mm maximum. Corner fillets are 0.6 mm on the shaft side and 0.3 mm on the opposite side. The effective load centre sits 15.5 mm from the reference face, which is the figure used when calculating the load split across a pair. Recommended grease charge is 0.44 g per bearing. The polyamide cage sets a 120°C ceiling, so heat is applied to the shaft rather than the bearing.

Interchange guidance

A 35 x 55 x 10 mm 25° universal bearing at light preload and ISO Class 4 from another maker substitutes directly. Variants of this number with a phenolic outer-ring-guided cage, such as a TR part, or with extra-light preload, or with the P4Y special bore and outside diameter tolerances, are related sizes: they share the envelope but change the speed capability, stiffness or matching tolerance.