NTN Drawn Cup Needle Roller Bearings

Detail Introduction :

This type of needle roller bearings generally do not use the inner ring, if you need to use the inner ring, you can choose IR type inner ring. drawn cup needle roller bearings are divided into bearing two ends perforated and bearing one end closed type. Compared with the perforated type drawn cup needle roller bearings, the closed end of the bearing is closed type, suitable for the shaft end, and can withstand small axial travel force.

Open and closed type drawn cup needle roller bearings are needle roller bearings with very small radial cross-sectional dimensions. They consist of a thin-walled drawn outer ring and needle rollers together with a cage assembly to form a complete unit. These designs make drawn cup needle roller bearings particularly compact, easy to mount and have a high radial load carrying capacity. To withstand axial forces, these bearings can be used in combination with thrust needle roller bearings.

Features of Drawn Cup Needle Roller Bearings:

Drawn Cup Needle Roller Bearings are equipped with thin and long rollers (roller length of 3 to 10 times the diameter, the diameter is generally not greater than 5mm), so the radial structure is compact, its inner diameter size and load capacity with other types of bearings of the same, the outer diameter is the smallest, especially suitable for radial installation size is limited by the support structure. Drawn outer ring needle roller bearings according to the use of different occasions, processing accuracy and surface quality should be combined with the bearing collar, use. Drawn cup needle roller bearings are bearing units that are a combination of radial needle roller bearings and thrust bearing components.

Most of the drawn cup needle roller bearings are single row design and have no lubrication holes, for special applications, open type drawn cup needle roller bearings are also available in full complement needle roller design. Drawn Cup Needle Roller Bearing require the raceways on the shaft to be hardened and ground. Since axial positioning methods such as shoulders and snap rings are not used, the bearing housing holes are easy and inexpensive to manufacture, so the mounting of Drawn Cup Needle Roller Bearings is simple.

In general, drawn cup needle roller bearings are characterized by a small structural space and a large load capacity.

Application of Drawn Cup Needle Roller Bearings:
NTN is a leading company in the bearing industry, in which the Drawn Cup Needle Roller Bearing developed and produced has a large load capacity and is suitable for support structures with restricted mounting dimensions. The surface of the journal is hardened as the rolling surface, and the bearing is fitted into the seat hole with a press fit, without the need to locate it axially again. The bearing should be filled with appropriate amount of grease before installation, usually, after assembly, no need to lubricate again, can be used in the bearing without the protruding end of the journal, the end face is closed to play a sealing role, and can withstand small axial play.

Since Drawn Cup Needle Roller Bearings are sealed with grease (lithium base grease), they can be used for long-term operation within the operating temperature range of -20 to +120°C. If the appropriate grease is replenished at the right time or in short-term use, they can be used at +130°C.

Nowadays, NTN's drawn outer ring needle roller bearings are widely used in automobiles, motorcycles, power-assisted vehicles, power tools, spinning machines, agricultural machines, industrial sewing machines, engineering machinery and other fields. The main application area is some machinery industry, of course the advantages of drawn cup needle roller bearings will be more obvious in the future, in the future, we will have a more comprehensive understanding of the use of drawn cup needle roller bearings.

More details about drawn cup needle roller bearing are shown below

1.Bearing Fits

It is common that drawn cup needle bearing is pressfitted in a housing by shrinkage fit so post press-fit inscribed circle diameter (Fw) comes to ISO Tolerance Rang Class F8. The post press-fit inscribed circle diameter (Fw) depends on the housing material and rigidity. It is therefore desirable to decide the interference based on the data measured in pre-testing. Where the housing rigidity is adequately high, the post press-fit inscribed circle diameter (Fw) is secured in nearly F8 range and nearly ordinary radial clearance can be got by adopting the data of bearing fit in housing and on shaft as shown in Table-1.

Table-1

2.Bearing installation

When installing a drawn cup needle roller bearing to a housing, place the jig on the marking side of the bearing,and then press-fit the bearing into the correct location in the housing bore. (A “pre-bent” bearing marked with a suffix including “M” has no directivity for installation.) Further, hammering directly the bearing ring in installing (press-fitting) is not allowed absolutely. In installing, it is recommended to use a mandrel with O-ring as illustrated in Fig.1 as a press-fitting jig. The use of this mandrel would enable to insert easily any drawn cup needle bearing in a housing without risk of twisting and fall-down.  Drawn cup needle roller bearing needs no a snap ring and a shoulder for positioning itself in a housing, but the bearing must be press-fitted so carefully as not to allow its side face to strike the shoulder for preventing it from deforming, where press-fitted in a housing with shoulder.

Fig. 1

The Type HCK for application to universal joints is fixed to the joint yoke by caulking, using a special-purposed assembler. Feel free to contact NTN for any inquiry about the special-purposed assembler (IPH Machine).

Fig. 2

3、Bearing Tolerances and Measuring Methods 

The outer ring of drawn cup needle roller bearing is so thin-walled that deformation thereof to a certain extent is unavoidable in the manufacturing processes, particularly in the heat-treating process. However, the outer ring is so designed that it is reformed normally from such deformation when being press-fitted in a housing with specific dimensional accuracy and, as a result, it can have the accuracy required to fulfill its specific function.

Hence, it is meaningless to measure the dimensional accuracy of bearing itself before being press-fitted. So, the following measuring method is used; a bearing to be measured is press-fitted in a linkage of specific dimension (20mm or more in wall thickness) and thereafter the inscribed circle diameter (Fw) is measured using a plug gauge or a taper gauge to evaluate the bearing accuracy.  Tables 4 to 7 show the dimensional tolerances for the bore diameter of each ring gauge and the roller set bore diameter (Fw) each of standard metric series drawn cup needle roller bearings Type HK and BK, heavy load series Type HMK (metric series), inch series Type DCL, and inch series HCK for application to universal joints. When measuring the roller set bore diameter (Fw) of a drawn cup needle roller bearing, the GO side dimension shall be the lower limit of dimensional tolerance of the roller set bore diameter; and the NOT GO side dimension shall be a sum of the upper limit of dimensional tolerance of the roller set bore diameter and 2μm. When measuring the roller set bore diameter of a drawn cup needle roller bearing, do not repeat insertion/removal with the ring gage. Also, do not install a bearing, which has been press-fitted into the ring gage for inspection, to an actual machine product.

Table 4

Table 5

Table 6

Table 7

4、Calculation Examples

Shrinkage factor and post-installation clearance of drawn cup needle roller bearing The recommended fit data for the standard bearings is as described in Table 1 on page B-35. This paragraph describes hereunder the calculation methods to be used when the bearing fit conditions are reviewed in detail.
1) Calculation of bearing shrinkage factor
For the drawn cup bearings, the shrinkage factor is For the drawn cup bearings, the shrinkage factor is calculated using the following method.

Fig. 3

λ＝  ・（0.7S2＋1.3）（1－t²）＋（0.7＋1.3t²）（1－S²2） 1－S2 E1 E2 E2
2t ……（1）
Where,
λ ：Outer ring shrinkage factor
DH ：Housing outer diameter mm 
dnom：Nominal diameter of fitting portion mm 
de ：Rolling surface diameter of outer ring mm
E1 ： Modulus of housing vertical elasticity
(Young’s modulus) MPa (kgf／mm2) E2 ：Modulus of outer ring vertical elasticity
(Young’s modulus)
2.07×106
MPa (21 200kgf／mm2

2)Inscribed circle diameter after complete bearing fit in the housing on actual machine
[1]Inscribed circle diameter in press-fitting of master ring

Fig. 4

H ：Housing inner diameter mm 
T ：Roller diameter + plate thickness mm 
D ：Outer diameter of drawn cup needle roller bearing mm 
Li ：Post press-fit inscribed circle diameter mm When the master ring is press-fitted, the dimension of "roller diameter + plate thickness" remains unchanged.Hence, the inscribed circle diameter Li is determined by the following formula.
Li＝D−2T−λ（D−H）＝（1−λ）D−2T＋λH …………(2)
Determine the mean value of "roller diameter + plate thickness" (=T) and standard deviation from formula (2).The mean value of formula (2) is determined as follows.

mLi＝（1−λ）mD−m2T＋λmH ………………………(3) 
Standard deviation of formula (2) 
σLi2＝（1−λ）2・σD2＋σ2T 2＋λ2σH 2 ………………(4) 
In the case of master ring, due to σH 2=0 the formula 
(4) is expressed as follows. 
σLi2＝（1−λ）2・σD2＋σ2T 2 ……………………………(5) 
The unknown values in formulas (3), (5) are only m2T and σ2T 2 . Hence, substitute the known numerical values for formulas (3), (5) to determine m2T and σ 2T 2. 
[2] Even when bearing ring is press-fitted in the housing on actual machine, consider the inscribed circle diameter similarly to the master ring press-fit. Herein, the calculation formulas for press-fit in the housing on actual machine can be discriminated as follows from formula (3), (4) by adding " ' " to each formula. 
mLi'＝（1−λ'）mD−m2T＋λ'mH' ……………………(6) 
σLi'2＝（1−λ'）2・σD2＋σ2T 2＋λ'2σH'2 ……………(7) 
[3] For m2T and σ2T 2 in formula (6), (7), substitute the values determined previously for the respective formula. 
[4] From the calculations, the inscribed circle diameter in press-fitting in the housing on actual machine can be expressed in the following formula 
Li'＝mLi'±3σLi' …………………………………………(8) 
[5] Radial internal clearance can be determined considering the mean value and standard deviation of shaft in formulas (6), (7). 
[6] The aiming radial internal clearance value is generally set up so an ordinary clearance can be got. However, the recommended clearance values are available 
every the individual portions in the case of bearing application to automobile. Feel free to contact NTN for the detail.

A complete guide to drawn cup needle roller bearings.
NTN is a bearing company with a very high reputation in the industry, can process and produce many different types of bearings, each bearing has a very high quality, of which drawn cup needle roller bearings is unanimously recognized by many manufacturers, different types of bearings have different use environments, today will provide you with a detailed introduction to drawn cup The needle roller bearings.

Some common questions about drawn cup needle roller bearings, the following will provide you with detailed answers: 1.

1. What is drawn cup needle roller bearings?

The outer ring of drawn cup needle roller bearings is precision stamped with thin steel plates, with a small structural space and a large load capacity. Suitable for installation space is limited and the shell hole is not suitable for the occasion of the raceway. And pressed into the bearing seat hole without further axial positioning.

Drawn outer ring needle roller bearings are needle roller bearings with thin drawn outer ring. Its main feature is the low cross-sectional height and high load bearing capacity. Mainly used for compact, inexpensive and bearing box bore can not be used as needle roller cage assembly raceway bearing configuration. The bearing and the bearing box must be installed by interference fit.

The drawn cup needle roller bearing generally does not have an inner ring attached, and the outer ring of the hardened steel plate of the drawn cup needle roller bearing is not separable from the needle roller cage assembly. The free space for storing lubricant can prolong the interval of supplementary lubrication. The bearings are generally of single row design, they are equipped with two needle roller cage assemblies, and the outer ring of the bearing has lubrication holes.

2. What are the advantages of drawn cup needle roller bearings?

drawn cup needle roller bearings are equipped with thin and long rollers (roller length is 3~10 times the diameter, the diameter is generally not more than 5mm), so the radial structure is compact, its inner diameter size and load capacity is the same as other types of bearings, the outer diameter is the smallest, especially suitable for radial installation size is restricted support structure. Needle roller bearings according to the use of different occasions, processing accuracy and surface quality should be combined with the bearing collar, use. drawn cup needle roller bearings is a combination of radial needle roller bearings and thrust bearing components of the bearing unit.

But because of the drawn cup needle roller bearingss bearing capacity, suitable for installation size restricted support structure, journal surface by hardening as rolling surface, bearing with press fit into the seat hole, no need to it again for axial positioning. The bearing should be injected with appropriate amount of grease before installation, usually, no need to lubricate again after assembly BK type bearing is used in the bearing of the journal without protruding end, the end face is closed to play a sealing role, and can withstand small axial play.

3.Why needle roller bearings should be axially positioned?

All shaft parts should have a definite position in the work, which has nothing to do with whether it is a bearing or not, whether it is a needle roller bearing.

Needle roller bearings are generally used to support the moving end of the part, allowing a small amount of axial displacement of the shaft and the housing (may be caused by the thermal deformation of the shaft). The bearing can be a needle roller bearing or a deep groove ball bearing, both of which are different due to the structure of the bearing and involve different parts of the shaft system. Deep groove ball bearings inside and outside the circle can not be separated, there is a fixed relative position, so you need to fix the inner ring of the bearing in the shaft ends fixed, the outer ring in the bearing seat swimming. drawn cup needle roller bearings itself inside and outside the circle can be separated, the bearing itself can achieve the purpose of swimming, so both inside and outside the circle to be fixed, imagine if also and deep groove ball bearings the same Imagine if and deep groove ball bearings, only fixed inner ring, outer ring is not fixed, the outer ring can also be unrestrained axial movement, even with the rolling body, inner ring completely separated.

4.drawn cup needle roller bearings axial fixation should be taken which way?

For the case of shaft rotation, bearing seat fixed, if the load direction remains unchanged, then generally take the shaft and the inner ring tightly, bearing seat and outer ring loose match. However, Drawn Cup Needle Roller Bearings are different, the outer ring of the drawn cup needle roller bearing and the bearing seat must be tightly matched, or interference fit, the reason is to ensure the roundness of the outer ring raceway, etc..

However, another role of interference fit is a certain degree of fixed outer ring, for needle roller most cases is enough, do not forget the characteristics of needle roller bearings ---- do not bear axial force. So can the installation of the bearing seat shoulders to limit it? Definitely not, in order to put the needle roller and cage into, a lip of the outer ring need annealing treatment, so very soft. Because it is very soft, this side should not be pressed into the end cap or the shoulder when mounting.

5. The process of drawn cup needle roller bearings.

The production process of drawn cup needle roller bearings includes blank forming, deburring, heat treatment, rough, fine, final grinding rolling surface, super finishing rolling surface or sawdust polishing and other processes. The front aspect of drawn cup needle roller bearings need to be well designed in order to produce the ideal needle roller bearing products. The heat treatment work of stamping outer ring needle roller bearings has high requirements on the process, if the problem of dimensional loss of control occurs during the processing of needle roller bearing blanks, then it is necessary to increase the grinding double end face process.

6.How should needle roller bearings be installed?

1. Installation of full complement needle roller bearings is generally carried out using auxiliary sleeves. Auxiliary roller or auxiliary sleeve to hold the needle roller does not make the needle roller fall out, the journal with its own chamfer will lift the needle roller, as the needle roller bearing in the journal slowly move in, auxiliary roller or auxiliary sleeve will slowly exit, until installed to the work position. Auxiliary roller, auxiliary sleeve outer diameter should be smaller than the shaft diameter 0.1-0.3mm.

Needle roller bearings can also be installed in this way, that is, the outer diameter of the auxiliary sleeve coated with a thin layer of lubricant, set into the outer ring of the bearing, so that the auxiliary sleeve and the outer ring of the bearing constitute an annular hole, and then installed in the annular hole needle roller. After installing the needle, use the work axis to push out the auxiliary sleeve.

3. For no inner ring or no outer ring needle roller bearings, installation, you can first shaft or shell hole rolling surface coated with a thin layer of grease, and the needle roller in turn close to the installation parts of the grease. Stick the last needle roller should leave a gap, the size of the gap in the circumference of the needle roller bearing to 0.5mm is appropriate.

4. For only the stamping outer ring needle roller bearings, because the outer ring wall is very thin, do not use the hand hammer to knock the installation, should use the press press into. Because when hammering, the pressure is not uniform, easy to make the outer ring of needle roller bearings produce local deformation.

7. What are the methods of disassembly of drawn cup needle roller bearings?

1. knocking method: knocking force is generally added to the inner ring of the bearing, shielding machine room knocking force should not be added to the rolling body of the bearing and keep frame, this method is simple and easy to use, but easy to damage the bearing, when the bearing is located at the end of the shaft, with less than the inner diameter of the bearing copper rod or other soft metal material against the shaft end, the lower part of the bearing with a cushion, with a hand hammer gently knocked, can be removed. Application of this method should pay attention to the placement of the cushion block to the appropriate location, the point of force should be correct.
2. Hot demolition method: used to dismantle the tight-fitting bearings. First, the oil heated to about 100 ℃ with the oil pot poured on the bearing to be removed, to be heated bearing ring expansion, you can use the pulling tool to pull out the bearing.
3. Push-press method: use the press to push the bearing, work smoothly and reliably, without damaging the machine and bearing shield machine room. Presses have manual pushing, mechanical or hydraulic presses pushing. Need to pay attention to the press point of force should be in the center of the shaft, shall not be pressed off.
4. Pull out method: using special pulling tools, when disassembling, just rotate the handle, the bearing will be slowly pulled out. When dismantling the outer ring of the bearing, the two legs of the puller should be bent outward and open; when dismantling the inner ring of the bearing, the two legs of the puller should be inward and stuck on the end surface of the inner ring of the bearing.
5.Open drawn outer ring needle roller bearings: open drawn outer ring needle roller bearings can be provided with needle roller and cage assembly or full loaded needle roller assembly of two types. Needle roller and cage assembly bearings have higher speed than full complement needle roller bearings.

8. What are the causes of drawn cup needle roller bearings?

By and large, 33.3% of drawn cup needle roller bearings damage is due to fatigue damage, 33.3% of drawn cup needle roller bearings are due to poor lubrication, and another 33.3% are due to contaminants entering the bearing or improper disposal of equipment.

Micro-dust cleaning bearings and the surrounding environment, invisible to the naked eye fine dust are powerful killers of bearings, it can increase the bearing wear, vibration and noise. Stamping in the use of equipment to form a strong stamping, it is very likely to lead to drawn cup needle roller bearing damage or the use of hammer direct knocking bearings, through the tumbling body to transfer pressure, etc.. The impact of non-professional tools installed using suitable and accurate equipment, you can strongly avoid the use of cloth and short fibers and other things. drawn cup needle roller bearings whether in the laboratory test or in actual use, it is clear to see that the appearance of the same needle roller bearings in the same operating conditions, the actual it has a great difference in life.

Bearings Model: