CN201843898U

CN201843898U - High-speed electric mainshaft bearing for machine tool

Info

Publication number: CN201843898U
Application number: CN2010205512395U
Authority: CN
Inventors: 戴学利; 王苏平; 陈振林; 胡守军; 杜德友; 牛建平
Original assignee: Zhejiang Bahuan Bearing Co Ltd
Current assignee: Zhejiang Bahuan Bearing Co Ltd
Priority date: 2010-10-08
Filing date: 2010-10-08
Publication date: 2011-05-25
Anticipated expiration: 2020-10-08

Abstract

The utility model provides a high-speed electric mainshaft bearing for a machine tool, which has reliable performance and low cost, and comprises an inner ring, an outer ring, a retainer and 18 steel balls. The diameter phi of each steel ball is 7.144mm. The groove depth of the outer ring is 0.2Dw, the channel curvature radius of the inner ring is 0.550Dw, and the fore shaft height of the inner ring 2 is 0.3mm-0.6mm. In the utility model, the working speed of a steel angular contact ball bearing is improved to 30000r/min from 24000r/min, and the rated dynamic load is increased to 22.99kN from 19.0kN, thereby the utility model provides the high-speed electric mainshaft bearing for the machine tool, which has high-speed performance, low cost and high cost performance.

Description

Lathe high-speed electric main shaft bearing

Technical field

The utility model relates to field of bearings.

Background technique

The electricity main shaft is high-speed machine tool " heart " parts, and electric mainshaft bearing should satisfy the requirement of high-speed motion, has higher rotating accuracy and lower temperature rise, has high as far as possible axial and radial accuracy, enough bearing capacitys etc. simultaneously.Adopt more block bearing to mainly contain at present in the high-speed main spindle unit: steel angular contact ball bearing, ceramic bearing, dynamic and hydrostatic bearing and magnetic bearing.

The steel angular contact bearing of ceramic bearing and same specification, same grade of accuracy is compared, though speed, life-span can improve, temperature rise can reduce, but price is about 2～3 times of the steel ball bearing, the machining accuracy of main is China's ceramic ball and ceramic ferrule can't satisfy the requirement of machine tool accuracy, also is not too many so in fact homemade ceramic bearing is used for electrical spindle for machine tool.

Dynamic and hydrostatic bearing is a kind of novel heavy wool wedge filmatic bearing that combines hydraulic bearing and hydrostatic bearing advantage, avoided hydrostatic bearing to generate heat down seriously at a high speed and the oil supply system bulky complex, overcome the weakness of contingent dry friction when hydraulic bearing starts and stops, good high speed performance is arranged, and speed-regulating range width.Its compact structure, dynamic and static rigidity is higher, but its price is higher, and working service is comparatively complicated, and standardization level is low, uses less in the ultra high speed main axle unit.

Magnetic bearing be utilize many secondary on circumference each other 180 ° of controlled electromagnets produce the opposite suction of radial direction, main shaft is suspended in the space, make a kind of novel high-performance bearing that does not have Mechanical Contact between axle journal and the bearing.Owing to do not exist Mechanical Contact, rotating shaft can reach high rotating accuracy, high rotational speed and bigger power, have simultaneously temperature rise low, need not to lubricate, advantage such as no oil pollution, life-span are grown.Again since the position in magnetic bearing axle center automatically adjust by the electron feedback control system, so main axis stiffness and Adjustable Damping, and dynamic balancing automatically, thus vibration is reduced to very low, make its noise little.Because magnetic bearing costs an arm and a leg, control system complexity, not large size popularization on the ultra high speed main axle unit for a long time.

Technological progress along with machining, require the processing of mechanical parts more and more accurate, and precision connects together with high speed, high speed grinding just has low grinding force and grinding heat, just can accomplish 80m/s with plain wheel abroad, and China 60m/s is less than, and will have high-speed spindle bearing to support so will carry out precision optical machinery processing.But under existing conditions, this speed up needs certain cost performance again, and speed is very high but selling at exorbitant prices also is difficult to apply (such as above said ceramic bearing, dynamic and hydrostatic bearing and magnetic bearing), thereby has market.

Summary of the invention

Technical problem to be solved in the utility model provides the low lathe of a kind of reliable performance cost high-speed electric main shaft bearing.For this reason, the utility model is by the following technical solutions: it comprises inner ring, outer ring, retainer and steel ball, the diameter of phi of described steel ball is 7.144mm, the quantity of steel ball is 18, the ditch depth of outer ring is 0.2Dw, the groove curvature radius of inner ring is 0.550Dw, and the fore shaft height of inner ring 2 is 0.3mm～0.6mm.

Also offer oil groove on the outer guide surface of retainer of the present utility model.

The steel electric mainshaft bearing is the angular contact ball bearing of 15 ° or 25 ° mostly with pressure angle, electric mainshaft bearing with medium model (brearing bore diameter 40mm) is an example, common bearing rotating speed is 18000r/min～24000r/min, and rotating speed will improve just very difficult again.Find that by research and test the main cause that influences steel angular contact ball bearing high speed performance is that the centrifugal force and the gyrostatic moment that act on down on the rolling element at a high speed increase.Centrifugal force increases the friction that can increase between rolling element and raceway, and the gyrostatic moment increase then can make between rolling element and raceway and produce sliding friction, makes pivot friction heating aggravation.Reach a conclusion by experimental study, the centrifugal force of rolling element and gyrostatic moment and rolling element diameter are closely related, and big centrifugal force of rolling element diameter and gyrostatic moment just increase.In order to improve the high speed performance of bearing, will take technical measures to reduce the centrifugal force and the gyrostatic moment of rolling element.Therefore the utility model adopts and reduces steel ball size, increases steel ball number, improves ditch depth than coefficient, improves technological means such as inside and outside ditch radius of curvature and realizes the rotating speed that bearing is higher.

Owing to adopt the technical solution of the utility model, the utlity model has following technique effect:

(1), reduce steel ball size (being reduced to Φ 7.144mm) from the Φ 7.938 of standard design, increase steel ball number (16 from standard design are increased to 18), can reduce centrifugal force and gyrostatic moment on the rolling element like this,

(2), the ditch depth of outer ring is increased to 0.2Dw from the 0.15Dw of standard design, can strengthen the bearing axial stiffness;

(3), the groove curvature radius of inner ring is increased by the 0.515Dw of standard design is 0.550Dw, can reduce the degree of making up of steel ball, improves thermal diffusivity between steel ball and raceway groove, helps high speed performance;

(4) increase the fore shaft height: the fore shaft height is increased big 0.3mm～0.6mm from about common 0.1mm, help the high speed rotating of bearing;

(5) on the outer guide surface of retainer, offer oil groove, be convenient to the storage of oil film, help further keeping good lubricating under the high speed conditions.

By above technological improvement, the utility model can improve 30000 r/min from 24000 r/min with the working speed of steel angular contact ball bearing, dynamic load rating is increased to 22.99kN from 19.0kN, thereby has improved a kind of possess high speed performance and the low high lathe of the cost performance high-speed electric main shaft bearing of cost.

Description of drawings

Fig. 1 is an embodiment's provided by the utility model sectional view.

Fig. 2 is for showing the schematic representation of outer ring ditch depth ratio.

Fig. 3 is the schematic representation of the groove curvature radius of demonstration inner ring.

Fig. 4 is for showing the schematic representation of fore shaft height.

Fig. 5 partly cuts open figure for retainer.

Embodiment

With reference to accompanying drawing 1-5.The utility model comprises inner ring 2, outer ring 1, retainer 4 and steel ball 3, and the diameter of phi of described steel ball 3 is 7.144mm, and the quantity of steel ball 3 is 18, the ditch depth H of outer ring 1 _DBe 0.2Dw, the groove curvature radius R of inner ring 2 is 0.550Dw, and the fore shaft height H of inner ring 2 is 0.3mm～0.6mm.

Offer oil groove on the outer guide surface 41 of retainer 4, described oil groove can symmetry be offered two row.

Claims

1. lathe high-speed electric main shaft bearing, comprise inner ring, outer ring, retainer and steel ball, the diameter of phi that it is characterized in that described steel ball is 7.144mm, the quantity of steel ball is 18, the ditch depth of outer ring is 0.2Dw, the groove curvature radius of inner ring is 0.550Dw, and the fore shaft height of inner ring (2) is 0.3mm～0.6mm.

2. lathe high-speed electric main shaft bearing as claimed in claim 1 is characterized in that offering oil groove on the outer guide surface of retainer.

3. lathe high-speed electric main shaft bearing as claimed in claim 2 is characterized in that the outer guide surface symmetry of retainer is offered two row oil grooves.