RA-Separable Outer Ring Type Precision Crossed Roller Bearings

RA-Separable Outer Ring Type (THK RA Series Slim Type Crossed Roller Bearings)

Slim Type Crossed Roller Bearings THK Series RA (IKO CRBS Series)

LYNBC Crossed Roller Bearings RA series ( THK corresponding to RA series, IKO corresponding to CRBS series), be subject to be separable outer ring type for inner ring rotation, these bearings are slim bearings having a small outside diameter, in comparison with the bore diameter, and a narrow width. The type with cage and the type with separator provide smooth rotation and suitable for applications where rotational speed is comparatively high. Both THK RA series and IKO CRBS series ,which is Slim type crossed roller bearings .

The THK RA be featured with no seal, seal attached on both ends and seal attached on either end. And the IKO CRBS defined by CRBS (open type, with cage); CRBS···V (open type, with full complement); CRBS···AUU(sealed type, with separator); CRBS···VUU(sealed type, with full complement).

▲ The design’s of all these Crossed Roller Bearings RA series are based on standard structures; LYNBC can design and manufacture many other similar structures in accordance to the special and particular requirements of their customers’. If our customer’s have specific requests then the customer should identify the structure, and mounting dimensions that are required. Please contact the LYNBC Technical Center if you need any assistance in this area.

Shaft diameter	Model No.	Main dimensions							Shoulder height		Basic load rating(radial)		Mass (kg)
		Inner diamete d	Outer diameter D	Roller pitch circle diameter dp	Width B B₁	Greasing hole		r_min	ds(max)	Dh(min)	C( kN)	C₀ ( kN)
		Inner diamete d	Outer diameter D	Roller pitch circle diameter dp	Width B B₁	a	b	r_min	ds(max)	Dh(min)	C( kN)	C₀ ( kN)
50	RA 5008	50	66	57	8	2	0.8	0.5	53.5	60.5	5.1	7.19	0.08
60	RA 6008	60	76	67	8	2	0.8	0.5	63.5	70.5	5.68	8.68	0.09
70	RA 7008	70	86	77	8	2	0.8	0.5	73.5	80.5	5.98	9.8	0.1
80	RA 8008	80	96	87	8	2	0.8	0.5	83.5	90.5	6.37	11.3	0.11
90	RA 9008	90	106	97	8	2	0.8	0.5	93.5	100.5	6.76	12.4	0.12
100	RA 10008	100	116	107	8	2	0.8	0.5	103.5	110.5	7.15	13.9	0.14
110	RA 11008	110	126	117	8	2	0.8	0.5	113.5	120.5	7.45	15	0.15
120	RA 12008	120	136	127	8	2	0.8	0.5	123.5	130.5	7.84	16.5	0.17
130	RA 13008	130	146	137	8	2	0.8	0.5	133.5	140.5	7.94	17.6	0.18
140	RA 14008	140	156	147	8	2	0.8	0.5	143.5	150.5	8.33	19.1	0.19
150	RA 15008	150	166	157	8	2	0.8	0.5	153.5	160.5	8.82	20.6	0.2
160	RA 16013	160	186	172	13	2.5	1.6	0.8	165	179	23.3	44.9	0.59
170	RA 17013	170	196	182	13	2.5	1.6	0.8	175	189	23.5	46.5	0.64
180	RA 18013	180	206	192	13	2.5	1.6	0.8	185	199	24.5	49.8	0.68
190	RA 19013	190	216	202	13	2.5	1.6	0.8	195	209	24.9	51.5	0.69
200	RA 20013	200	226	212	13	2.5	1.6	0.8	205	219	25.8	54.7	0.71

Shaft diameter	Model No.	Main dimensions						Shoulder height		Basic load rating(radial)		Mass (kg)
Shaft diameter	Model No.	Inner diameter d	Outer diameter D	Roller pitch circle diameter dp	Width B B₁	Greasing hole d₀	r_min	ds (max)	Dh (min)	C( kN)	C₀( kN)	Mass (kg)
50	RA 5008C	50	66	57	8	1.5	0.5	53.5	60.5	5.1	7.19	0.08
60	RA 6008C	60	76	67	8	1.5	0.5	63.5	70.5	5.68	8.68	0.09
70	RA 7008C	70	86	77	8	1.5	0.5	73.5	80.5	5.98	9.8	0.1
80	RA 8008C	80	96	87	8	1.5	0.5	83.5	90.5	6.37	11.3	0.11
90	RA 9008C	90	106	97	8	1.5	0.5	93.5	100.5	6.76	12.4	0.12
100	RA 10008C	100	116	107	8	1.5	0.5	103.5	110.5	7.15	13.9	0.14
110	RA 11008C	110	126	117	8	1.5	0.5	113.5	120.5	7.45	15	0.15
120	RA 12008C	120	136	127	8	1.5	0.5	123.5	130.5	7.84	16.5	0.17
130	RA 13008C	130	146	137	8	1.5	0.5	133.5	140.5	7.94	17.6	0.18
140	RA 14008C	140	156	147	8	1.5	0.5	143.5	150.5	8.33	19.1	0.19
150	RA 15008C	150	166	157	8	1.5	0.5	153.5	160.5	8.82	20.6	0.2
160	RA 16013C	160	186	172	13	2	0.8	165	179	23.3	44.9	0.59
170	RA 17013C	170	196	182	13	2	0.8	175	189	23.5	46.5	0.64
180	RA 18013C	180	206	192	13	2	0.8	185	199	24.5	49.8	0.68
190	RA 19013C	190	216	202	13	2	0.8	195	209	24.9	51.5	0.69
200	RA 20013C	200	226	212	13	2	0.8	205	219	25.8	54.7	0.71

THK RA Series Slim Type Crossed Roller Bearings

THK's RA series slim-type crossed roller bearings are a popular choice for applications requiring high rigidity, high rotational accuracy, and compact design. Here's a breakdown of their key features, benefits, applications, and considerations:

Key Features

Slim Profile: The defining characteristic of the RA series is its thin cross-section. This allows for significant space savings and contributes to smaller, lighter machine designs.

Crossed Roller Design: Cylindrical rollers are arranged perpendicularly to each other, with alternating rollers supporting different directions of load. This configuration enables the bearing to handle radial loads, axial loads, and moment loads simultaneously.

High Rigidity: The crossed roller arrangement and precision manufacturing contribute to high stiffness, minimizing deflection under load. This is crucial for applications requiring precise positioning and movement.

High Rotational Accuracy: THK's manufacturing processes and quality control result in bearings with exceptional rotational accuracy, minimizing runout and ensuring smooth, precise motion.

Integral Inner and Outer Rings (Generally): Most RA series bearings have integrated inner and outer rings, simplifying mounting and reducing the number of components required. However, be sure to check the specific part number as some variations may exist.

Preloaded: Typically preloaded to optimize rigidity and minimize backlash. The preload is usually specified in the part number or product datasheet.

Lubrication: Requires proper lubrication for optimal performance and longevity. The type of lubricant (grease or oil) and lubrication intervals are typically specified in the THK documentation.

Benefits

Space Saving: The slim profile allows for smaller, more compact machine designs.

High Load Capacity: The crossed roller design can withstand complex loading conditions.

High Rigidity and Accuracy: Provides precise and stable performance.

Simplified Mounting: Integrated rings (generally) simplify the assembly process.

Reduced Component Count: Integrated design reduces the number of components required.

Smooth and Precise Motion: Minimizes runout and provides smooth rotational movement.

Long Service Life: With proper lubrication and maintenance, these bearings can provide a long service life.

Applications

The RA series is well-suited for a variety of applications requiring high precision, rigidity, and compact design, including:

Robotics: Robot joints, especially where space is limited.

Machine Tools: Rotary tables, indexing tables, and precision positioning systems.

Semiconductor Manufacturing Equipment: Wafer handling and processing equipment.

Medical Equipment: CT scanners, X-ray machines, and surgical robots.

Optical Instruments: Telescopes, microscopes, and other precision optical devices.

Aerospace: Actuators and control systems where weight and size are critical.

Other Precision Equipment: Any application requiring high accuracy and stiffness in a compact space.

Considerations When Selecting an RA Series Bearing

Load Capacity: Carefully calculate the static and dynamic loads the bearing will experience and select a bearing with adequate capacity.

Operating Speed: Consider the maximum operating speed and select a bearing with appropriate speed capabilities and lubrication requirements.

Operating Temperature: Ensure the bearing is suitable for the expected operating temperature range.

Preload: Choose the appropriate preload level based on the application's rigidity and backlash requirements.

Lubrication: Select the correct lubricant and establish a proper lubrication schedule.

Mounting: Follow THK's recommended mounting procedures to ensure proper bearing performance and prevent damage. Torque values for mounting bolts are critical.

Sealing: Consider the environment and select a bearing with appropriate sealing to protect against contamination. Some RA series bearings offer integrated seals.

Part Number Configuration: Understand the THK part numbering system to correctly identify and order the specific RA series bearing you need. This includes size, preload, and any other specific features.

Accuracy Class: THK offers different accuracy classes for its bearings. Choose the appropriate class based on the required precision of the application.

Availability: Check the lead time and availability of the desired bearing.