CN2668301Y - High speed spindle pretightening device combining constant pressure pretightening with positioning pretightening - Google Patents

Abstract

The utility model discloses a high speed spindle pretightening device combining constant pressure pretightening with positioning pretightening, characterized in that an outer sleeve (4), a spring sleeve (2) which is provided with a spring (3) inside and an inner sleeve (5) are arranged between two groups of main shaft bearings (1). The sum of the length of the outer sleeve (4) and the spring sleeve (2) is equal to the length of the inner sleeve (5). The utility model overcomes the defect of a single positioning pretightening device and a constant pressure pretightening device. When the main shaft runs up, the deformation of the main shaft can be automatically compensated through the deformation of the spring, which can ensure the preload of the bearings elementally constant; when the main shaft and the bearings are dismounted, the bearings disengage from the bearing saddle bores by buffeting or oppressing the outer ring of the bearing, which can avoid the damage to the grounders of the bearings and the inner and the outer raceway.

Description

The high-speed main spindle pre-tightening apparatus that the level pressure pretension combines with the location pretension

Technical field the utility model belongs to mechanical manufacturing field, is specifically related to a kind of pre-tightening apparatus of high-speed processing machine tool high speed main shaft.

The background technique high-speed main spindle is the key feature of high-speed processing machine tool.High-speed main spindle realizes that the key of high speed and precision processing is that main shaft not only can run up in operation process, and running accuracy height, vibration are little, and main shaft has enough rigidity and bears radial and axial chip-load simultaneously.Realize speed, precision and the rigidity requirement of above-mentioned main shaft, one of key technology applies appropriate preload to main shaft bearing exactly.But main shaft is in running, because bearing heating produces factor affecting such as spindle deformation, the preload of bearing is constantly changing.Should Bearing preload appropriate, require preload stable again, and will guarantee the easy installation and removal of main shaft and bearing, become one of the key issue that will consider in the main shaft design.

The firmly beforehand means that the tradition main shaft bearing adopts is single level pressure firmly beforehand means or location firmly beforehand means.The level pressure pretension helps main shaft and realizes speed up, and when main shaft caused the main shaft elongation because of temperature distortion, the level pressure pretension can compensate the distortion of main shaft automatically by camber of spring, and guaranteed that the preload of bearing is constant substantially.The deficiency of this firmly beforehand means is during from bearing saddle bore dismounting main shaft and bearing, owing to there is big gap between the sleeve of both ends of the spring, need axial impact or compressing main shaft, and by main shaft upper bearing (metal) inner ring and spin bearing outer ring is applied active force and just can make bearing break away from bearing support, be easy to damage bearing.The location firmly beforehand means is owing to saved component such as spring, and structure is simple relatively, has obtained extensive use in the not high occasion of rate request, and its dismounting is also simple and easy to do.But when spindle speed was very high, because bearing temperature rise is higher, elongation strain can take place in main shaft vertically, and this distortion can cause Bearing preload to change; If preload increases, can cause bearing temperature further to raise, shorten bearing working life, the stuck or burnout failure of bearing takes place when serious; If preload reduces, can produce negative effects such as main axis stiffness decline, limit speed reduction and running accuracy reduction.

Model utility content technical problem to be solved in the utility model is to provide a kind of level pressure pretension and locatees the high-speed main spindle pre-tightening apparatus that pretension combines, it can not only be when main shaft runs up, can compensate the distortion of main shaft by camber of spring automatically, guarantee that the preload of bearing is constant substantially; And when dismounting main shaft and bearing, can be directly by impacting or the compressing bearing outer ring make bearing break away from bearing saddle bore, can not produce destruction to bearing ball and inside and outside raceway.

The utility model is to solve above-mentioned technical problem by following technological scheme: the high-speed main spindle pre-tightening apparatus that level pressure pretension of the present utility model combines with the location pretension, it is characterized in that: it is to be provided with outer sleeve, spring spool and inner sleeve between two groups of main shaft bearings, be provided with spring in the spring spool, the length sum of described outer sleeve and spring spool and the equal in length of inner sleeve.

Described outer sleeve is provided with and makes itself and main shaft casing that the locating stud that axially relatively moves not take place.

The utility model combines the level pressure pretension of main shaft in the high-speed processing machine tool effectively with the pre-clamping method in location, has overcome the shortcoming of single location pre-tightening apparatus or level pressure pre-tightening apparatus.The length sum of outer sleeve and spring spool is set to the equal in length with inner sleeve.When dismounting main shaft or main shaft when turning round under the low speed, bearing outside tube and spring spool are in contact condition, main shaft bearing shows as the location firmly beforehand means; Can directly make bearing break away from bearing saddle bore during dismounting, can not produce destruction bearing ball and inside and outside raceway by impacting or oppressing bearing outer ring.When main shaft runs up, because bearing temperature rise makes main shaft that elongation strain take place vertically, cause bearing outside tube and spring spool separating contacting state, bearing becomes the level pressure firmly beforehand means; Can compensate the distortion of main shaft by camber of spring automatically, guarantee that the preload of bearing is constant substantially, to adapt to the needs of main shaft speed up.

Description of drawings

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

Each label is represented among the figure:

1, main shaft bearing, 2, spring spool, 3, spring, 4, outer sleeve,

5, inner sleeve, 6, locating stud, 7, main shaft, 8, the main shaft casing.

Embodiment

As shown in Figure 1, the high-speed main spindle pre-tightening apparatus that level pressure pretension of the present utility model combines with the location pretension, be that 1 of two groups of main shaft bearing at main shaft 7 are provided with outer sleeve 4, spring spool 2 and inner sleeve 5, be provided with spring 3 in the spring spool 2, outer sleeve 4 and the length sum of spring spool 2 and the equal in length of inner sleeve 5.Both error in lengths should guarantee that the actual preload of main shaft bearing 1 in the preload that allows, is generally less than 50 microns.Outer sleeve 4 is provided with locating stud 6, is fixed on the main shaft casing 8 by this locating stud 6, makes itself and main shaft casing 8 not take place axially to relatively move.When dismounting main shaft 7 or main shaft 7 when turning round under the low speed, the firmly beforehand means of main shaft bearing 1 is the location pretension; Can directly make main shaft bearing 1 break away from bearing saddle bore during dismounting, can not produce destruction the spin and the inside and outside raceway of main shaft bearing 1 by impacting or oppressing main shaft bearing 1 outer ring.When main shaft 7 ran up, main shaft bearing 1 temperature rise made main shaft 7 that elongation strain take place vertically, and the firmly beforehand means of main shaft bearing 1 becomes the level pressure pretension; It can compensate the distortion of main shaft 7 automatically by spring 3 distortion, and guarantees that the preload of bearing 1 is constant substantially.

Working principle of the present utility model is: during main shaft 7 low-speed runnings, outer sleeve 4 and the length sum of spring spool 2 and the equal in length of inner sleeve 5, the crack is zero between outer sleeve 4 and the spring spool 2, the firmly beforehand means of main shaft bearing 1 shows as the location pretension, at this moment, main shaft bearing 1 preload is by the relative position decision of each abutment sleeve of the inside and outside circle of the bearing left and right sides.When main shaft 7 ran up, main shaft bearing 1 temperature rise made main shaft 7 heatings, and elongation strain takes place vertically, and the gap between outer sleeve 4 and the spring spool 2 no longer is zero; Because the generation in gap, at this moment, the firmly beforehand means of main shaft bearing 1 shows as the level pressure pretension, and the preload of main shaft bearing 1 is by the amount of deformation decision of spring 3; Can compensate the distortion of main shaft 7 automatically by spring 3 distortion, and guarantee that the preload of main shaft bearing 1 is constant substantially.

Claims (2)

1, a kind of level pressure pretension and the location high-speed main spindle pre-tightening apparatus that combines of pretension, it is characterized in that: it is to be provided with outer sleeve (4), spring spool (2) and inner sleeve (5) between two groups of main shaft bearings (1), be provided with spring (3) in the spring spool (2), described outer sleeve (4) and the length sum of spring spool (2) and the equal in length of inner sleeve (5).

2, level pressure pretension according to claim 1 and the location high-speed main spindle pre-tightening apparatus that combines of pretension is characterized in that described outer sleeve (4) is provided with to make itself and main shaft casing (8) that the locating stud (6) that axially relatively moves not take place.