CN215903196U

CN215903196U - Novel high-speed and high-precision numerical control internal grinding machine and dynamic and static pressure bearing used by same

Info

Publication number: CN215903196U
Application number: CN202120818435.2U
Authority: CN
Inventors: 邓力凡
Original assignee: Hunan Mechanical and Electrical Polytechnic
Current assignee: Hunan Mechanical and Electrical Polytechnic
Priority date: 2021-04-21
Filing date: 2021-04-21
Publication date: 2022-02-25
Anticipated expiration: 2031-04-21

Abstract

The utility model provides a novel high-speed and high-precision numerical control internal grinding machine and a dynamic and static pressure bearing used by the same, wherein the bearing is a shaft sleeveFormula, dark shallow chamber, four oily cheque structures, including bearing body and main shaft, its characterized in that: an Archimedes spiral surface area is arranged along the circumferential direction of the inner wall of the bearing body, the Archimedes spiral surface area is from 216 degrees to 155 degrees and is 30', and the every degree lift of the Archimedes spiral line of the Archimedes spiral surface area

Figure DEST_PATH_533348DEST_PATH_IMAGE002

. The dynamic and static pressure bearing has the characteristics of high precision, high rigidity, high bearing capacity and good vibration absorption and anti-seismic performance, and provides a foundation for high-precision and high-efficiency processing of inner circle grinding.

Description

Novel high-speed and high-precision numerical control internal grinding machine and dynamic and static pressure bearing used by same

Technical Field

The utility model relates to the field of bearings and processing thereof, in particular to a novel high-speed and high-precision numerical control internal grinding machine and a dynamic and static pressure bearing used by the same.

Background

The hydrodynamic-hydrostatic bearing has high precision, high rigidity, long service life and good vibration absorption and shock resistance, and is mainly used for the main shaft of precision processing machinery and high-speed and high-precision equipment. The machine tool can be used for modifying an old machine tool and can also be used for matching with a new machine tool. The dynamic and static pressure bearing can completely recover the machining precision and the surface roughness of the machine tool lost due to the problem of the main shaft bearing; the precision and the cutting efficiency of the machine tool spindle are improved; and can be continuously used for many years without maintenance. Many enterprises adopt hybrid bearings to form a new machine tool and reform old machine tool equipment, and satisfactory use effects and remarkable economic benefits are obtained.

The hydrodynamic and hydrostatic bearings integrate the advantages of hydrostatic bearings and eliminate the disadvantages of the two bearings. The bearing is characterized in that when the integral bearing and the oil cavity bearing system with the surface deep and shallow cavity structure work, a main shaft is floated by a layer of pressure oil film, and the main shaft is driven by a motor to be suspended between the bearings to generate mechanical friction and abrasion, so that the service life of the bearings is prolonged, and the bearing has good precision retentivity. When the motor drives the main shaft to rotate, a dynamic and static pressure bearing oil film is naturally formed in the bearing oil cavity due to the step effect, and the bearing becomes a dynamic pressure sliding bearing with a static pressure field. Compared with three or five tiles, the hybrid bearing is an integral structure, has large contact area with a box body hole, is in rigid connection, and fully exerts and utilizes the rigidity of an oil film. When the main shaft works, the oil film rigidity is the superposition of the static rigidity and the dynamic rigidity of the bearing, and the bearing capacity is very strong. The homogenization of the pressure oil film can make the main shaft rotation precision higher than the machining precision of the shaft neck and the bearing.

However, the bearing capacity and rigidity of the existing hybrid bearing still need to be improved, and when a bearing structure is designed and improved, a quick calculation method is needed, and a quick calculation method for the bearing capacity and rigidity of the hybrid bearing is absent at present, so that a grinding head spindle system uses a common bearing, the rotation precision and the bearing rigidity of the common bearing have a lifting space, and the machining size precision and the shape and position precision are influenced.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a novel high-speed and high-precision numerical control internal grinding machine and a dynamic and static pressure bearing used by the same, and solves the problems of processing size precision and shape and position precision.

In order to achieve the above purpose, the utility model provides the following technical scheme: a kind of hybrid bearing, including bearing body and main axis, there are Archimedes spiral surface area along the peripheral direction of the inner wall of bearing body, Archimedes spiral surface area is from 216 degrees to 155 degrees 30' end, Archimedes spiral every degree lift range of Archimedes spiral surface area

The Archimedes spiral surface area comprises a shallow cavity, the end part of the Archimedes spiral surface area is provided with a deep cavity for forming a bearing lubricating oil cavity, 4 axial oil return grooves of 4 x 1.26 are uniformly formed in a bearing body, one axial oil return groove is communicated with the deep cavity, and the depth of the deep cavity is h_p＝1.0。

A novel high-speed and high-precision numerical control internal grinding machine is provided, wherein the numerical control internal grinding machine is 5 shafts and comprises an X shaft, a C shaft, a Z shaft, a U shaft and a W shaft, the numerical control internal grinding machine comprises a grinding carriage, a grinding head spindle system, a dresser, a headstock, a direct drive motor, a speed reduction motor, a first sliding plate and a second sliding plate, the grinding carriage is arranged on the first sliding plate to form the Z shaft, the grinding head spindle system and the dresser are both arranged on the grinding carriage, the headstock is arranged on the second sliding plate to form the X shaft, the direct drive motor and the speed reduction motor are arranged on the headstock, and the direct drive motor drives the headstock to rotate to form the C shaft;

the grinding head main shaft system comprises a main shaft motor, a main shaft box body, a main shaft, a front dynamic and static pressure bearing and a rear dynamic and static pressure bearing, wherein the front dynamic and static pressure bearing and the rear dynamic and static pressure bearing are both the dynamic and static pressure bearing, the main shaft is arranged on the main shaft box body through the front dynamic and static pressure bearing and the rear dynamic and static pressure bearing, and an output shaft of the main shaft motor is connected with the main shaft;

the trimmer comprises a first direct-drive servo motor, a first linear guide rail, a second direct-drive servo motor, a second linear guide rail and a trimming diamond cutter, wherein the first direct-drive servo motor is installed on the first linear guide rail to form a W shaft, the second direct-drive servo motor is installed on the second linear guide rail to form a U shaft, and the trimming diamond cutter is arranged on the U shaft.

The beneficial effects are that the technical scheme of this application possesses following technological effect:

the dynamic and static pressure bearing has the characteristics of high precision, high rigidity, high bearing capacity and good vibration absorption and anti-seismic performance, and provides a foundation for high-precision and high-efficiency processing of inner circle grinding.

It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be considered as part of the inventive subject matter of the present disclosure unless such concepts are mutually inconsistent.

The foregoing and other aspects, embodiments and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. Additional aspects of the present invention, such as features and/or advantages of exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of specific embodiments in accordance with the teachings of the present invention.

Drawings

The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a hybrid bearing structure according to the present invention.

Fig. 2 is a whole diagram of the novel high-speed and high-precision numerical control internal grinding machine.

Fig. 3 is a schematic view of the grinding head spindle system of the present invention.

Fig. 4 is a schematic view of a dresser according to the present invention.

Fig. 5 is a schematic diagram of a processing method of the novel high-speed and high-precision numerical control internal grinding machine.

FIG. 6 is a schematic diagram of a method for calculating the bearing capacity and stiffness of a hybrid bearing according to the present invention.

FIG. 7 is a schematic view of a method for calculating the bearing capacity and stiffness of a hybrid bearing according to the present invention

FIG. 8 is a schematic view of a method for calculating the bearing capacity and stiffness of a hybrid bearing according to the present invention

In the figures, the meaning of the reference numerals is as follows: 1. a bearing body; 2. a main shaft; 3. an axial oil return groove; 4. a grinding head spindle system; 5. a finisher; 6. a head frame; 7. a direct drive motor; 8. a first slide plate; 9. a second slide plate; 10. a grinding carriage; 11. a reduction motor; 401. a spindle motor; 402. a rear hybrid bearing; 403. a front hybrid bearing; 501. a first servo motor; 502. A second servo motor; 503. a first linear guide rail; 504. a second linear guide; 405. and (5) finishing the diamond cutter.

Detailed Description

In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings. In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily intended to include all aspects of the utility model. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any one implementation. In addition, some aspects of the present disclosure may be used alone, or in any suitable combination with other aspects of the present disclosure.

The embodiment provides a hybrid bearing, as shown in fig. 1, comprising a bearing body 1 and a main shaft 2, wherein an archimedes spiral surface area is arranged along the circumferential direction of the inner wall of the bearing body 1, the archimedes spiral surface area is from 216 degrees to 155 degrees and ends at 30 degrees, and the archimedes spiral of the archimedes spiral surface area lifts per degree

Defining the flow area as A to increase the flow area A and increase the static pressure load force

The Archimedes spiral surface area comprises a shallow cavity, the end part of the Archimedes spiral surface area is provided with a deep cavity for forming a bearing lubricating oil cavity, 4 axial oil return grooves of 4 x 1.26 are uniformly formed in the bearing body 1, one axial oil return groove is communicated with the deep cavity, the length a of the oil sealing surface is reduced,

decrease; increase the load factor

Thereby increasing the bearing load; as shown in fig. 8.

Depth of deep cavity is h_pThe width of the deep cavity oil wedge is increased to 1.0, so that the dynamic pressure W is increased_dThe load force is increased and the load is increased,

a method for calculating the bearing capacity and rigidity of a hybrid bearing uses the following formula:

the formula of the dynamic pressure bearing capacity of the dynamic and static pressure bearing is as follows:

the formula of the static pressure bearing capacity of the hybrid bearing is as follows:

the formula of the axial bearing force of the hybrid bearing is as follows:

a novel high-speed and high-precision numerical control internal grinding machine is shown in figures 2-4, the numerical control internal grinding machine is 5 shafts and comprises an X shaft, a C shaft, a Z shaft, a U shaft and a W shaft, the numerical control internal grinding machine comprises a grinding carriage 10, a grinding head spindle system 4, a dresser 5, a headstock 6, a direct drive motor 7, a speed reduction motor 11, a first sliding plate 8 and a second sliding plate 9, the grinding carriage 10 is arranged on the first sliding plate 8 to form the Z shaft, the grinding head spindle system 4 and the dresser 5 are both arranged on the grinding carriage 10, the headstock 6 is arranged on the second sliding plate 9 to form the X shaft, the direct drive motor 7 and the speed reduction motor 11 are arranged on the headstock 6, and the direct drive motor 7 drives the headstock 6 to rotate to form the C shaft;

the grinding head main shaft system 4 comprises a main shaft motor 401, a main shaft box body, a main shaft 2, a front hybrid bearing 403 and a rear hybrid bearing 402, wherein the front hybrid bearing 403 and the rear hybrid bearing 402 are both the hybrid bearings, the main shaft is arranged on the main shaft box body through the front hybrid bearing 402 and the rear hybrid bearing 403, and an output shaft of the main shaft motor 1 is connected with the main shaft; the embodiment is an external electric main shaft, a motor rotor shaft, namely a grinding main shaft, is arranged in two dynamic and static pressure bearings with the shaft diameter phi of 60 of 30-003 and 30-004, the load capacity is high, the radial run-out of the main shaft is less than or equal to 0.0015, the rotation precision is high, and the bearing rigidity is high. These criteria are not comparable to rolling bearings of the same specifications. The rotor and the stator of the Swiss are adopted as the motor, the rotating speed is 36000rpm and 4.3kw, and the motor is arranged outside the box body without cooling; taking the minimum grinding wheel phi 15 as an example, the grinding wheel speed is as follows: the minimum is 28m/s, which cannot be achieved by the existing internal grinding machine; the main shaft and the rotor inner hole are as follows: 1:20 taper connection and good self-locking property. At the front end of the main shaft, a grinding wheel cutter bar is positioned in an inner hole of the main shaft by a No. 4 Morse cone, and two end face keys of the main shaft transmit torque.

The dresser 5 includes a first direct-drive servo motor 501, a first linear guide 503, a second direct-drive servo motor 502, a second linear guide 5034, and a dressing diamond blade 505, the first direct-drive servo motor 501 is mounted on the first linear guide 503 to form a W axis, the second direct-drive servo motor 502 is mounted on the second linear guide 504 to form a U axis, and the dressing diamond blade 505 is disposed on the U axis.

The machine tool processing method comprises the following steps: during grinding, according to the shape and size of a workpiece, a longitudinal grinding method can be adopted, as shown in (a) in fig. 5, and a plunge grinding method can be adopted, as shown in (b) in fig. 5, some common internal grinding machines are provided with special end grinding devices, and inner holes and end faces can be ground in one clamping process, as shown in (c) in fig. 5.

In order to verify the bearing capacity and rigidity calculation method of the hybrid bearing, the following derivation process is given, and the length of the bearing is set:

the length of the bearing is as follows: l ═ 156;

the length of the bearing is as follows: l ═ 1 to 1.5D (1);

d, shaft diameter of the bearing;

shallow cavity: consisting of an archimedes spiral (by scraping),

lift per degree

Archimedes spiral area 60.5 °;

starting point radius:

end point radius:

simultaneously, the Archimedes spiral line and the shaft diameter surface form a restrictor (form static pressure), and the width of 1 shallow cavity:

flow area a of the shallow cavity:

A＝B₁×L_x mm² (4)；

L_x-the length of the cavity;

bearing capacity W of 1 shallow cavity oil wedge:

since the bearing load capacity W is the area integral of the bearing gallery pressure distribution, namely:

W＝∫∫_Dp_rAds；

wherein:

(load factor).

Oil seal surface length a:

therefore:

width of deep cavity: width of 1 deep cavity oil wedge:

wherein: the depth of the deep cavity is taken as follows: h is_pThe deep cavity constitutes the dynamic pressure, 1.

A dynamic pressure oil wedge bearing capacity:

wherein:

then: bearing capacity of bearing (1 oil wedge):

to be provided with

The bearings of the shaft diameter are as follows:

W＝W_j+W_d＝700kg。

it can be seen that: of shallow-bore archimedes' spirals

Directly influencing R_mThereby affecting the width B1 of the shallow cavity and also affecting the flow area a, and ultimately affecting the coining bearing capacity; depth h of the deep cavity_pDirectly affects the width B2 of the deep cavity and thus the bearing capacity of the dynamic pressure.

Calculation of the load of a hybrid bearing:

the dynamic pressure radial bearing capacity of the whole bearing is as follows: f_d；

See fig. 6, force analysis:

∴F_d+p₁cos61°+p₂cos29°＝p₃cos61°+p₄cos29°

∴

e, the vertical offset of the center of the main shaft after the bearing is loaded; c_l-a side stream coefficient;

when e is 0.5h, formula 10 is reduced to:

∴

to be provided with

Figure DEST_PATH_GDA00034902744200000910

The bearings of the shaft diameter are as follows: substituting known parameters to obtain:

dynamic pressure load force of the whole bearing: f_d＝3330kg；

The static pressure radial bearing capacity of the whole bearing is as follows: f_j；

See fig. 7 force analysis:

∵

F_j＝A(p_r4-p_r2)＝0.168DπL_x(p_r4-p_r3)；

and:

h₂a gap between the static pressure oil wedge 2 and the shaft diameter; h is₄-clearance of hydrostatic oil wedge 4 with shaft diameter; c. C_T-throttling factor 0.62;

the flow rate coefficient of the water flow is,

when h is generated₄＝0.5h₂And h is₂When 0.04, formula 13 converts to:

to be provided with

The bearing of the shaft diameter is taken as an example: substituting known parameters to obtain:

F_j＝48360N＝4836kg。

therefore, the radial load force of the entire bearing: f_{Radial assembly}＝7716kg。

The radial load of the angular contact roller bearing with the same shaft diameter is as follows: 3600-7500 kg, it can be seen that the radial load of the hybrid bearing is 1-2 times or equal to that of the angular contact roller bearing with the same shaft diameter.

Axial bearing capacity of the whole bearing: f_z；

If the oil pressure of the main shaft system is adjusted as follows: 10kg/cm 2;

F_z＝10×10×10⁴×π(0.12²-0.11²)＝1×10⁶×7.22×10^-3＝7220N＝722kg。

rigidity of dynamic and static pressure bearing dynamic work:

the dynamic working stability of the hybrid bearing is dependent on its stiffness,

f-external load; e-the offset of the shaft diameter center;

defined by the stiffness:

beta-throttle ratio; w- -oil cavity load;

to be provided with

the rigidity of the hybrid bearing with the same shaft diameter is slightly higher or 1-1.5 times higher than that of a rolling bearing, so that the stability, the continuity and the reliability of the precision of the hybrid bearing are much better than those of the hybrid bearing.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. The utility model provides a hybrid bearing, the bearing is axle sleeve formula, dark shallow cavity, four oily cheise structures, including bearing body and main shaft, its characterized in that: an Archimedes spiral surface area is arranged along the circumferential direction of the inner wall of the bearing body, the Archimedes spiral surface area is from 216 degrees to 155 degrees and is 30', and the every degree lift of the Archimedes spiral line of the Archimedes spiral surface area

2. The utility model provides a novel high-speed, high-accuracy numerical control internal grinding machine, numerical control internal grinding machine is 5 axles, including X axle, C axle, Z axle, U axle and W axle, its characterized in that: the numerical control internal grinding machine comprises a grinding carriage, a grinding head spindle system, a dresser, a headstock, a direct drive motor, a speed reduction motor, a first sliding plate and a second sliding plate, wherein the grinding carriage is arranged on the first sliding plate to form a Z axis;

the grinding head main shaft system comprises a main shaft motor, a main shaft box body, a main shaft, a front dynamic and static pressure bearing and a rear dynamic and static pressure bearing, wherein the front dynamic and static pressure bearing and the rear dynamic and static pressure bearing are both dynamic and static pressure bearings as claimed in claim 1, the main shaft is arranged on the main shaft box body through the front dynamic and static pressure bearing and the rear dynamic and static pressure bearing, and an output shaft of the main shaft motor is connected with the main shaft;