CN201284790Y

CN201284790Y - Silicon nitride ceramics ball bearing

Info

Publication number: CN201284790Y
Application number: CNU2008201916693U
Authority: CN
Inventors: 吴少伟; 尹大友
Original assignee: Hubei New Torch Science & Technology Co Ltd
Current assignee: The new torch Science and Technology Ltd. in Hubei
Priority date: 2008-10-23
Filing date: 2008-10-23
Publication date: 2009-08-05
Anticipated expiration: 2018-10-23

Abstract

The utility model relates to a silicon nitride ceramic ball bearing used on a spindle of a precise and high-speed machine tool. A groove is arranged between the outer ring and the inner ring of the silicon nitride ceramic ball bearing. A rolling body is installed in a window of a cage and embedded into the groove between the outer ring and the inner ring. A hole is arranged at the center of the inner ring. The material for the rolling body is silicon nitride ceramic. Multi-lip and multi-cavity sealing rings are installed on the two end surface between the outer ring and the inner ring. Dustproof covers are installed outside. The material for the cage is high-rigidity engineering plastics. Magnetic materials are applied to manufacture the dustproof covers. The utility model utilizes a silicon nitride ceramic ball to replace a traditional steel ball used in a rolling body of a bearing. The silicon nitride ceramic ball has the advantages that the density and the elastic deformation after being stressed are small, elative loading rigidity is high and the thermal expansion coefficient, the friction coefficient and the heat generated during operation are relatively small, the accuracy of the ball is improved, the accuracy of the groove between the outer ring and the inner ring and the accuracy of the cage size are improved and the asynchronous thrash accuracy is decreased to one second of the previous asynchronous thrash accuracy. Due to the high accuracy of the bearing, the rotating accuracy of the spindle of the machine tool is improved and the quality of the precise part surface and the mould cutting surface is also improved.

Description

Silicon nitride ceramic ball bearing

Affiliated technical field

The utility model relates to the high-precision bearing in a kind of mechanical transmissioning technology field, especially for silicon nitride ceramic ball bearing accurate, the high-speed machine tool main shaft.

Background technique

Bearing is the complete sets of basic equipment spare of modern machine, it is the foundation stone that the machine finish index guarantees, its performance directly has influence on rotating speed, rotating accuracy, rigidity, trembling vibration cutting ability, noise, temperature rise and the thermal distortion etc. of lathe, and then has influence on precision, the surface quality of processing accessories.In traditional mechanical or common mechanical, rotating speed mainly forwards several thousand rev/mins at hundreds of.Along with the fast development of Numeric Control Technology, " compound, at a high speed, intelligence, accurate, environmental protection " become the main trend of current machine tool industry technical development because, High-speed machining can improve effectively lathe work efficiency, shorten process-cycle of workpiece.Modern High-Speed working machine tool, spindle speed require to reach several ten thousand and forward tens0000 rev/mins to.This just requires machine tool chief axis and associated components thereof will adapt to the demand of High-speed machining, and the design of bearing has been proposed brand-new requirement.If the high speed adaptability of bearing is bad, the temperature rise meeting of axis system is very serious, even can burn inefficacy to death.Therefore, high performance lathe must the high performance bearing of adapted.The precision of bearing can be divided into P0, P6, P5, P4 and five grades of P2, morpheme error such as the circular runout of main shaft bearing, end face run-out, rolling element diameter are inconsistent can have a strong impact on the precision of axis system and workpiece thereof, be used for bearing accuracy on the modern machine main shaft should be P5 and more than, and for numerical control machine tool, machining center etc. at a high speed, the main shaft bearing of high-accuracy lathe, then need select P4 and higher level high-precision bearing thereof for use.Because the machine tool mainshaft bearing highi degree of accuracy, at a high speed, high reliability request, the rolling element material is had some specific (special) requirements, and the rotating speed of general bearing steel rolling body bearing and temperature rise, life-span and bearing capacity, rigidity and vibration resistance, noise can not satisfy the requirement of modern machine.

Summary of the invention

For overcoming the deficiencies in the prior art, goal of the invention of the present utility model is to provide a kind of silicon nitride ceramic ball bearing, by adopting silicon nitride ceramic ball to substitute the rolling element of traditional steel ball as bearing, to realize the high precision int of bearing, the purpose of the main shaft rotation precision of raising lathe and the quality of precise part surface and die cuts bevel.

The technical solution of the utility model is: between the outer ring of bearing and the inner ring groove is arranged, rolling element is contained in the window of retainer, and in the groove between embedding outer ring and the inner ring, the center of inner ring is porose, be used for linking to each other with axle, the transmission of realizable force is characterized in that: the material of rolling element is a silicon nitride ceramics.

The both ends of the surface of the utility model between outer ring and inner ring are equipped with the rubber seal of many lips multi-cavity, and rubber seal is equipped with dust cover outward.The material of retainer is high rigidity engineering plastics, and dust cover is made of magnetic material.

The utility model adopts the ceramic ball higher than Metal Ball rigidity, in the precision that improves ball, has also improved the precision of inner ring and outer ring groove and the dimensional accuracy of retainer, 1/2 before asynchronous runout precision has been reduced to.By the high precision int of bearing, can improve the quality of the main shaft rotation precision of lathe and precise part surface and die cuts bevel, realized effectively the metal rolling element the rotation requirement of inaccessible ultra high speed, ultra-high precision.

The utility model is compared with traditional bearing, has the following advantages:

1, density is little: lightweight and the speed up that can realize bearing.

2, rigidity height: the resiliently deformable after stressed is little, and the rigidity height of load approximately can improve rigidity 15%～20%, thereby alleviate the vibration of lathe relatively.

3, thermal expansion coefficient is little: the temperature variant dimensional changes amount of stupalith is little, and the hot preload that produces is lower, thereby has avoided too much heat accumulation to become fatigue flake to lose efficacy.

4, friction factor is little: the heat that produces during work is less, greatly reduces the stress of material and oiling agent in the traditional bearing.

Description of drawings

Below in conjunction with accompanying drawing the utility model is further described.

Fig. 1 is a structural representation of the present utility model;

Fig. 2 is the local enlarged diagram of Fig. 1 sealing configuration.

Embodiment

As shown in Figure 1, on the external diameter of the internal diameter of outer ring 1 of the present utility model and inner ring 5, with rolling element 6 contact position cross section being arranged all is oval or circular groove, torque is through the raceway groove of inner ring 1, rolling element 6, the raceway groove of outer ring 5 transmits, inner ring 5 is two, two inner ring internal diameter size mutual deviations must not be greater than 0.004mm, outer ring 1, inner ring 5 usefulness Bearing Steels are made, through cold roll, modified, slightly, behind the finish turning, carry out superaudio surface hardening heat treatment, again through isothermal tempering, corase grind, correct grinding, superfine milling is shaped, adopt the superaudio quenching technology, well solved because homemade steel exist oxygen content and the too high problem of impurity, the transition layer of workpiece and the quench-hardened case depth are restive, tissue, quality problems such as uniformity of hardness is relatively poor, production is reached to adopt domestic steel (product cost is reduced), make quality reach external technical standard requirement again, use the homemade inside and outside super smart special purpose grinder of raceway groove, this machine table revolution Location accuracy less than 1 ', use this equipment, inner and outer ring raceway groove deviation from circular from can reach in the 0.09 μ m, and surface roughness can reach between 0.022～0.05 μ m; Rolling element 6 is contained in the window of retainer 4, and rolling element 6 is two row, also can be single-row or 3 row, and in the groove between embedding outer ring 1 and the inner ring 5; The center of inner ring 5 is porose, is used for linking to each other with axle the transmission of realizable force; Axial internal clearance 1-15um; Both ends of the surface between outer ring 1 and inner ring 5 are equipped with

rubber seal

2 and 7, its

outer dust cover

3 and 8 of being equipped with.

Be accompanied by main shaft of numerical control machine tool and develop, main shaft bearing has been proposed high speed, high rigidity, low temperature rise, long-life requirement to speed up.And stupalith (mainly referring to the Si3N4 engineering ceramics) is because of having premium properties such as density is little, Young's modulus is high, thermal expansion coefficient is little, wear-resisting, high temperature resistant, corrosion-resistant, thereby becomes the ideal material of making high-speed precision bearing.The material of rolling element 6 is a silicon nitride ceramics.Substitute the rolling element of Bearing Steel as bearing with the silicon nitride ceramic material, the application of stupalith has broken through many application limit of conventional steel bearing, as high speed, wear resistance, insulating properties, temperature tolerance.Silicon nitride ceramics proportion commonly used only is more than 1/3 of steel, and the 6 pairs of outer rings of rolling element 1 that therefore cause under high speed reduce greatly with the stress level of inner ring 5, and unidimensional bearing limit speed significantly promotes; The hardness of silicon nitride ceramics reaches 1500HV, is a times of Bearing Steel, and high temperature resistant to reach 1200 ℃ be 6 times of Bearing Steel, and these have expanded the using scope of conventional steel bearing undoubtedly.Realized effectively the metal rolling element the rotation requirement of inaccessible ultra high speed, ultra-high precision.

Retainer 4 materials adopt high rigidity engineering plastics, make that 4 pairs of grease degradation influences of retainer are little, it is more abundant to lubricate, heat resistance is better, main shaft bearing temperature rise when running up reduces 10%, and simultaneously, this new bearing series can make the highest lifting 10% of rotating speed under identical boundary conditions.So, not only dimensional accuracy is improved, and the distortion that centrifugal force causes when rotating also reduced, and retainer 4 has also reduced half with the guide clearance of outer ring.With the lathe diameter of axle is that 50 millimeters, rotating speed are that 8000rpm is an example, and the synchronous runout precision of bearing is 0.8 micron, and asynchronous runout precision is 0.07 micron, and the synchronous runout precision of machine tool chief axis has reached 1.1 microns, and asynchronous runout precision has reached 0.15 micron.

High-speed precise machine tool is not only had higher requirement to the design and the manufacturing of bearing, and the development of sealing and lubrication system has been proposed specific (special) requirements.Lubricating condition in order to guarantee bearing operation effectively the time, can reduce as far as possible even prevent sneaking into of dust again, the present invention adopts the both ends of the surface between outer ring 1 and inner ring 5 that

rubber seal

2 and 7 are housed, its outer sealing configuration that

dust cover

3 and 8 are housed is when

seal ring

2 and 7 assembles with

dust cover

3 and 8 and the 1 end face sinking 0.2mm of outer ring.

As shown in Figure 2,1 is the outer ring, and 5 is inner ring, and 2 is rubber seal, and 3 is dust cover.The sealing configuration of many lips multi-cavity is adopted in bearing seal, whole sealing configuration is made up of one three lip seal circle 2 and a magnetic dust cover 3, the metal frame outer rim is through overground processing on the seal ring, ellipse and dimensional accuracy have been guaranteed, this external diameter and bearing outer ring 1 hole wall interference fit, do not produce relative movement between seal ring 2 and the outer ring 1, grease can not ooze out by the surface of contact slit.

Also adopt big interference fit between dust cover 3 and the bearing inner race 5, dust cover 3 rotates with inner ring, is subjected to the effect of rotary centrifugal force, and outside water, dust all can be thrown out along the dust cover outer end, can not enter in the seal ring chamber, can not enter bearing cavity yet through interference face; By three lip contact seals, two lips are in diametric(al) between dust cover 3 and the seal ring 2, and another lip forms three inner chambers in dust cover 3 end face directions between seal ring 2 and the dust cover 3.This structure has effectively increased the product seal space, adopts this technology to leak the fat problem from solved bearing at all; Dust cover 3 usefulness magnetic materials are made, and have greatly strengthened the rigidity of dust cover, and are not yielding after press-fiting, and dust sealing can be good.Be filled into mouthful " POLYREX.EM " lubricating grease 7%p0.5g in the bearing; Realized the long lifetime, low temperature rise.

Claims

1, a kind of silicon nitride ceramic ball bearing, between outer ring (1) and the inner ring (5) groove is arranged, rolling element (6) is contained in the window of retainer (4), and in the groove between embedding outer ring (1) and the inner ring (5), the center of inner ring (5) is porose, be used for linking to each other with axle, the transmission of realizable force is characterized in that: the material of rolling element (6) is a silicon nitride ceramics.

2, silicon nitride ceramic ball bearing according to claim 1 is characterized in that: the material of retainer (4) is high rigidity engineering plastics.

3, silicon nitride ceramic ball bearing according to claim 1 is characterized in that: the both ends of the surface between outer ring (1) and inner ring (5) are equipped with rubber seal (2) and (7).

4, silicon nitride ceramic ball bearing according to claim 3 is characterized in that: said rubber seal (2) and (7) are the sealing configuration of many lips multi-cavity.

5, silicon nitride ceramic ball bearing according to claim 3 is characterized in that: outer dust cover (3) and (8) of being equipped with in rubber seal (2) and (7).

6, silicon nitride ceramic ball bearing according to claim 5 is characterized in that: said dust cover (3) and (8) make of magnetic material.