CN108161036B - A machining center ultrasonic electric spindle with automatic adjustment of bearing pretightening force - Google Patents

Abstract

An ultrasonic electric spindle of a machining center with automatic adjustment of the bearing pretightening force, a double water cooling structure is designed for the loss and heat generation of the stator and rotor of the electric spindle, and the efficient heat dissipation of the stator and rotor is realized through two layers of cooling water jackets inside and outside the shell, reducing the heat dissipation of the stator and rotor The impact of heat generation and high temperature on the main shaft and bearings; in view of the friction and heat generation of the bearing itself, the bearing outer ring fixing sleeve is designed as a cooling water jacket structure, and the bearing outer ring fixing sleeve with water cooling function can realize efficient heat dissipation of the bearing, supplemented by high-efficiency lubrication, Reduce the thermal deformation of the bearing; in the case of higher speed, the water cooling and lubrication effect will decrease, and the influence of thermal deformation must be offset by applying an appropriate preload to the bearing. First, the temperature sensor of the bearing preload automatic adjustment mechanism is used to monitor the bearing temperature in real time , and feed back the monitored bearing temperature data to the CNC system of the machine tool, and then output control signals through the CNC system of the machine tool to change the elongation of the piezoelectric ceramic column to generate a suitable bearing preload.

Description

A machining center ultrasonic electric spindle with automatic adjustment of bearing pretightening force

technical field

The invention belongs to the technical field of machine tool electric spindles, in particular to an ultrasonic electric spindle of a machining center with automatic adjustment of bearing pretightening force.

Background technique

In recent years, more and more machining centers have adopted ultrasonic electric spindles. Ultrasonic electric spindles not only have the advantages of compact structure, light weight, small inertia, low noise, fast response, high speed and high power, but also can be assisted by ultrasonic waves. processing. The electric spindle is a new technology that integrates the machine tool spindle and the spindle motor, and this transmission structure that combines the machine tool spindle and the spindle motor "into one" effectively makes the spindle components relative to each other from the machine tool's transmission system and the overall structure. independent, while the machine tool spindle is directly driven by the built-in motor, thus shortening the length of the main transmission chain of the machine tool to zero and realizing the "zero transmission" of the machine tool.

Since the machining accuracy of the machine tool directly determines the precision machining quality of the parts, and at the same time, the running accuracy of the electric spindle directly affects the machining accuracy of the machine tool. Therefore, in order to ensure the precision machining quality of the parts, it is necessary to ensure the running accuracy of the electric spindle. The running accuracy of the electric spindle is determined by many factors, one of which is the pretightening force of the bearing. As the core component of the electric spindle, the bearing pretightening force not only determines the performance and life of the bearing, but also affects The vibration amplitude of the shaft end of the electric spindle, as the processing conditions change, the temperature of the bearing may rise rapidly, resulting in thermal deformation of the bearing, and the support accuracy of the bearing will also change accordingly. In order to reduce the variation range of the bearing support accuracy , the usual method is to provide preload through the spring, but due to the limitation of the spring output preload mode, the preload output by the spring cannot be adjusted. Since the bearing preload cannot be adjusted, it is impossible to pass a suitable preload. force to deal with the thermal deformation of the bearing. Therefore, at the present stage, the ultrasonic electric spindle of the machining center that uses the spring as the pre-tightening force application part generally has the situation that the higher the speed is, the lower the machining accuracy is, which seriously restricts the high-speed development of the machining center.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides an ultrasonic electric spindle of a machining center with automatic adjustment of the bearing pretightening force. For the first time, the automatic adjustment function of the bearing pretightening force is introduced into the ultrasonic electric spindle of the machining center, and at the same time, piezoelectric ceramics are used as The pre-tightening force output part can automatically adjust the pre-tightening force output according to the temperature of the bearing, which effectively ensures the bearing support accuracy and provides a strong guarantee for the high-speed development of the machining center. At the same time, in order to further reduce the temperature rise of the bearing, the electric Spindle cooling and lubrication structure.

In order to achieve the above object, the present invention adopts the following technical solutions: a machining center ultrasonic electric spindle with automatic adjustment of bearing pretightening force, including a spindle, a housing, an upper end cover, a lower end cover, a rotor coil, and a stator coil; the rotor coil The fixed sleeve is installed in the middle of the main shaft, the stator coil is fixedly installed on the inner surface of the housing, and the first cooling water jacket is installed between the stator coil and the housing, and the outer surface of the housing at the axial position of the first cooling water jacket is added. A second cooling water jacket is installed; a first spiral cooling water channel is provided in the first cooling water jacket, and the water inlet of the first spiral cooling water channel and the water outlet of the first spiral cooling water channel are both arranged on the shell; A second spiral cooling water channel is arranged in the second cooling water jacket, and the water inlet of the second spiral cooling water channel and the water outlet of the second spiral cooling water channel are directly arranged on the second cooling water jacket; at the water inlet of the first spiral cooling water channel 1. The water outlet of the first spiral cooling water channel, the water inlet of the second spiral cooling water channel and the water outlet of the second spiral cooling water channel are all equipped with cooling water connectors; It is installed in the mouth of the bottom end of the shell, and an adapter sleeve is installed between the lower end cover and the shell, and the main shaft passes through the adapter sleeve and the lower end cover in turn and extends to the outside of the shell; On the main shaft between the rotor coils, from bottom to top, the first angular contact ball bearing, the first bearing lubricating sleeve and the second angular contact ball bearing, the inner ring of the first angular contact ball bearing and the second angular contact ball bearing Interference connection with the main shaft, the outer rings of the first angular contact ball bearing and the second angular contact ball bearing are in interference connection with the inner surface of the adapter sleeve through the first fixed sleeve of the bearing outer ring; on the main shaft above the rotor coil , from bottom to top, the rotor fastening nut, the third angular contact ball bearing, the second bearing lubricating sleeve, the fourth angular contact ball bearing, the automatic adjustment mechanism of bearing pretightening force and the axial limit nut of the bearing, the third angular contact ball The inner rings of the bearing and the fourth angular contact ball bearing are in interference connection with the main shaft, and the outer rings of the third angular contact ball bearing and the fourth angular contact ball bearing are in interference connection with the housing through the second fixed sleeve of the bearing outer ring. The second bearing lubricating sleeve and the bearing pretightening force automatic adjustment mechanism are in interference connection with the second fixed sleeve of the bearing outer ring; the axial limit nut of the bearing is threadedly connected with the second fixed sleeve of the bearing outer ring; the main shaft is a hollow shaft, There is a tie rod in the center hole of the main shaft, the top of the tie rod extends out of the upper hole of the main shaft, a pull rod axial limit nut is installed on the top of the pull rod, and a disc spring is set on the top of the main shaft, between the pull rod axial limit nut and the disc spring A force transmission sleeve is arranged between them; a hydraulic cylinder is installed on the lower surface of the upper end cover directly above the tie rod, the piston rod of the hydraulic cylinder is facing downward, and the piston rod of the hydraulic cylinder is set opposite to the top of the tie rod; at the bottom of the tie rod The end is connected with an ultrasonic generator, a horn and a knife handle locking mechanism in turn, and the knife handle locking mechanism is used in conjunction with the knife handle.

A first lubricating oil passage is arranged in the first fixed sleeve of the bearing outer ring, a second lubricating oil passage is arranged in the adapter sleeve, and the oil outlet end of the first lubricating oil passage is connected with the first bearing lubricating sleeve In communication, the oil inlet end of the first lubricating oil passage communicates with the oil outlet end of the second lubricating oil passage, and a first lubricating oil connector is installed at the oil inlet end of the second lubricating oil passage.

An electric spindle connection port is installed on the upper end cover; a third lubricating oil passage is arranged in the second fixed sleeve of the bearing outer ring, and the oil outlet end of the third lubricating oil passage communicates with the second bearing lubricating sleeve. The housing is provided with a fourth lubricating oil passage, the oil inlet end of the third lubricating oil passage communicates with the oil outlet end of the fourth lubricating oil passage, and the second lubricating oil connection is installed on the oil inlet end of the fourth lubricating oil passage. Mouth.

An annular cooling water tank is also provided in the first fixed sleeve of the bearing outer ring, and an annular cooling water tank inlet water channel and an annular cooling water tank outlet water channel are respectively provided on the adapter sleeve, and the annular cooling water tank inlet water channel and There is an included angle of 180° between the water outlet channels of the annular cooling water tank.

The bearing pretightening force automatic adjustment mechanism includes a piezoelectric ceramic column, a piezoelectric ceramic column fixing seat, a piezoelectric ceramic column radial positioning plate, a first force transmission plate, a spring, a second force transmission plate and a temperature sensor; The ceramic column fixing seat, the piezoelectric ceramic column radial positioning plate, the first force transmission plate and the second force transmission plate are all interference-connected on the second fixed sleeve of the bearing outer ring; the number of the piezoelectric ceramic columns is several, and the number of pressure The electric ceramic columns are uniformly arranged on the circumferential direction of the piezoelectric ceramic column fixing seat; the piezoelectric ceramic column positioning holes are opened on the radial positioning plate of the piezoelectric ceramic columns, and the piezoelectric ceramic columns pass through the piezoelectric ceramic column positioning holes and the second piezoelectric ceramic column positioning hole. A force transmission plate is in contact with it; the spring is connected between the first force transmission plate and the second force transmission plate, and the second force transmission plate is in contact with the outer ring of the fourth angular contact ball bearing; the spring The quantity is several, and several springs are evenly distributed in the circumferential direction between the first force transmission plate and the second force transmission plate; the temperature sensor is installed on the second force transmission plate, and the piezoelectric ceramic column adjusts the axial direction through the temperature data fed back by the temperature sensor. Elongation, by adjusting the axial elongation of the piezoelectric ceramic column to automatically adjust the bearing pretightening force.

Beneficial effects of the present invention:

The ultrasonic electric spindle of the machining center with automatic adjustment of the bearing pretightening force of the present invention introduces the automatic adjustment function of the bearing pretightening force into the ultrasonic electric spindle of the machining center for the first time, and at the same time uses piezoelectric ceramics as the pretightening force output part, which can be used according to the bearing's The temperature automatically adjusts the pretightening force output, which effectively ensures the bearing support accuracy and provides a strong guarantee for the high-speed development of the machining center. At the same time, in order to further reduce the temperature rise of the bearing, the cooling and lubrication structure of the electric spindle is also optimized.

Description of drawings

Fig. 1 is a schematic diagram of the structure of an ultrasonic motorized spindle of a machining center with automatic bearing pretightening force adjustment according to the present invention;

Fig. 2 is an enlarged view of part I in Fig. 1;

In the figure, 1—main shaft, 2—housing, 3—upper end cover, 4—lower end cover, 5—rotor coil, 6—stator coil, 7—first cooling water jacket, 8—second cooling water jacket, 9— The first spiral cooling water channel, 10—the water inlet of the first spiral cooling water channel, 11—the water outlet of the first spiral cooling water channel, 12—the second spiral cooling water channel, 13—the water inlet of the second spiral cooling water channel, 14—the second spiral cooling water channel Water outlet, 15—transfer sleeve, 16—first angular contact ball bearing, 17—first bearing lubricating sleeve, 18—second angular contact ball bearing, 19—automatic adjustment mechanism for bearing preload, 20—bearing The first fixed sleeve of the outer ring, 21—rotor fastening nut, 22—the third angular contact ball bearing, 23—the second bearing lubricating sleeve, 24—the fourth angular contact ball bearing, 25—the axial limit nut of the bearing, 26— The second fixed sleeve of the bearing outer ring, 27—tie rod, 28—the axial limit nut of the pull rod, 29—disc spring, 30—force transmission sleeve, 31—hydraulic cylinder, 32—ultrasonic generator, 33—horn, 34—knife handle locking mechanism, 35—knife handle, 36—first lubricating oil passage, 37—second lubricating oil passage, 38—first lubricating oil connector, 39—electric spindle wiring port, 40—third lubrication Oil passage, 41—the fourth lubricating oil passage, 42—the second lubricating oil nozzle, 43—annular cooling water tank, 44—annular cooling water tank inlet water channel, 45—annular cooling water tank outlet water channel, 46—piezoelectric ceramic column, 47—fixed seat of piezoelectric ceramic column, 48—radial positioning plate of piezoelectric ceramic column, 49—first force transmission plate, 50—spring, 51—second force transmission plate, 52—temperature sensor.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1 and 2, a machining center ultrasonic electric spindle with automatic adjustment of bearing pretightening force includes a spindle 1, a housing 2, an upper end cover 3, a lower end cover 4, a rotor coil 5, and a stator coil 6; The rotor coil 5 is fixedly set in the middle of the main shaft 1, the stator coil 6 is fixedly installed on the inner surface of the housing 2, and a first cooling water jacket 7 is installed between the stator coil 6 and the housing 2, and the first cooling water jacket The outer surface of the housing 2 at the axial position of 7 is equipped with a second cooling water jacket 8; the first spiral cooling water channel 9 is arranged in the first cooling water jacket 7, the first spiral cooling water channel water inlet 10 and The water outlets 11 of the first spiral cooling water channel are all arranged on the housing 2; the second spiral cooling water channel 12 is arranged in the second cooling water jacket 8, the water inlet 13 of the second spiral cooling water channel and the outlet of the second spiral cooling water channel The water outlets 14 are all directly arranged on the second cooling water jacket 8; at the water inlet 10 of the first spiral cooling water channel, the water outlet 11 of the first spiral cooling water channel, the water inlet 13 of the second spiral cooling water channel and the outlet of the second spiral cooling water channel Cooling water nozzles are installed on the nozzles 14; the upper end cover 3 is fixed on the top end of the shell 2, the lower end cover 4 is fixed on the bottom end of the shell 2, and the gap between the lower end cover 4 and the shell 2 An adapter sleeve 15 is installed, and the main shaft 1 passes through the adapter sleeve 15 and the lower end cover 4 in turn and extends to the outside of the housing 2; on the main shaft 1 between the lower end cover 4 and the rotor coil 5, The first angular contact ball bearing 16, the first bearing lubricating sleeve 17 and the second angular contact ball bearing 18 are installed in sequence from bottom to top, the inner ring of the first angular contact ball bearing 16 and the second angular contact ball bearing 18 and the main shaft 1 Interference connection, the outer rings of the first angular contact ball bearing 16 and the second angular contact ball bearing 18 are interference connected with the inner surface of the adapter sleeve 15 through the first fixed sleeve 20 of the bearing outer ring; above the rotor coil 5 On the main shaft 1, the rotor fastening nut 21, the third angular contact ball bearing 22, the second bearing lubricating sleeve 23, the fourth angular contact ball bearing 24, the bearing preload automatic adjustment mechanism 19 and the bearing shaft are sequentially installed from bottom to top To the limit nut 25, the inner rings of the third angular contact ball bearing 22 and the fourth angular contact ball bearing 24 are in interference connection with the main shaft 1, and the outer rings of the third angular contact ball bearing 22 and the fourth angular contact ball bearing 24 pass through the outer ring of the bearing The second fixed sleeve 26 of the ring is in interference connection with the housing 2, and the second bearing lubricating sleeve 23 and the bearing pretightening force automatic adjustment mechanism 19 are in interference connection with the second fixed sleeve 26 of the outer ring of the bearing; the axial limit of the bearing The bit nut 25 is threadedly connected with the second fixed sleeve 26 of the outer ring of the bearing; the main shaft 1 is a hollow shaft, and a pull rod 27 is arranged in the central hole of the main shaft 1, and the top end of the pull rod 27 extends out of the upper opening of the main shaft 1. A pull rod axial limit nut 28 is installed on the top, a disc spring 29 is set on the top of the main shaft 1, and a force transmission sleeve 30 is arranged between the pull rod axial limit nut 28 and the disc spring 29; A hydraulic cylinder 31 is installed on the lower surface of the upper end cover 3, and the piston rod of the hydraulic cylinder 31 is facing downward, and the piston rod of the hydraulic cylinder 31 is arranged opposite to the top of the pull rod 27; , Horn 33 and knife handle locking mechanism 34, and knife handle locking mechanism 34 is used in conjunction with knife handle 35.

A first lubricating oil passage 36 is arranged in the first fixed sleeve 20 of the bearing outer ring, a second lubricating oil passage 37 is arranged in the adapter sleeve 15, and the oil outlet end of the first lubricating oil passage 36 is connected to The first bearing lubricating sleeve 17 communicates, the oil inlet end of the first lubricating oil passage 36 communicates with the oil outlet end of the second lubricating oil passage 37, and the first lubricating oil connector is installed at the oil inlet end of the second lubricating oil passage 37 38.

An electric spindle connection port 39 is installed on the upper end cover 3; a third lubricating oil passage 40 is arranged in the second fixed sleeve 26 of the bearing outer ring, and the oil outlet end of the third lubricating oil passage 40 is connected to the second bearing The lubricating sleeve 23 communicates, and a fourth lubricating oil passage 41 is opened on the housing 2. The oil inlet end of the third lubricating oil passage 40 communicates with the oil outlet end of the fourth lubricating oil passage 41, and the fourth lubricating oil passage 41 A second lubricating oil nipple 42 is installed at the oil inlet end of the lubricating oil.

An annular cooling water tank 43 is also provided in the first fixed sleeve 20 of the bearing outer ring, and an annular cooling water tank inlet water channel 44 and an annular cooling water tank outlet water channel 45 are respectively provided on the adapter sleeve 15, and the annular cooling water tank There is an included angle of 180° between the water inlet channel 44 of the water tank and the outlet channel 45 of the annular cooling water tank.

The bearing pretightening force automatic adjustment mechanism 19 includes a piezoelectric ceramic column 46, a piezoelectric ceramic column fixing seat 47, a piezoelectric ceramic column radial positioning plate 48, a first force transmission plate 49, a spring 50, a second force transmission plate 51 and the temperature sensor 52; the piezoelectric ceramic column fixing seat 47, the piezoelectric ceramic column radial positioning plate 48, the first force transmission plate 49 and the second force transmission plate 51 are all interference connected to the second fixed sleeve 26 of the outer ring of the bearing above; the number of piezoelectric ceramic columns 46 is several, and several piezoelectric ceramic columns 46 are uniformly arranged on the circumferential direction of the piezoelectric ceramic column fixing seat 38; piezoelectric ceramic columns are provided on the radial positioning plate 39 of the piezoelectric ceramic columns The positioning hole, the piezoelectric ceramic column 46 passes through the positioning hole of the piezoelectric ceramic column and contacts the first force transmission plate 49; the spring 50 is connected between the first force transmission plate 49 and the second force transmission plate 51, and the second force transmission plate 51 The second force transmission plate 51 is in contact with the outer ring of the fourth angular contact ball bearing 24; the number of said springs 50 is several, and several springs 50 are arranged circumferentially evenly between the first force transmission plate 49 and the second force transmission plate 51 The temperature sensor 52 is installed on the second force transmission plate 51, and the piezoelectric ceramic column 46 adjusts the axial elongation through the temperature data fed back by the temperature sensor 52, and the bearing is carried out by adjusting the axial elongation of the piezoelectric ceramic column 46. Automatic adjustment of preload.

During the operation of the machining center, the temperature factor is the primary factor affecting the machining accuracy. In order to reduce the heating behavior of the ultrasonic motorized spindle of the machining center, the present invention specially designs a double water-cooling structure for the loss and heating of the stator and rotor. Through the first cooling water jacket 7 and the second The second cooling water jacket 8 quickly generates heat with the loss of the stator and rotor, effectively reducing the temperature of the stator and rotor, thereby reducing the adverse effects of the high temperature of the stator and rotor on the main shaft 1 and bearings. In addition, in addition to the influence factor of stator and rotor loss and heat generation, there is also the frictional heat generation of the bearing itself. The present invention also separately designs a water-cooling structure for the frictional heat generation of the bearings. At the same time, a lubricating structure is designed for all bearings to reduce the degree of bearing friction. Supplemented by water cooling and heat dissipation, the frictional heat of the bearing is limited to the greatest extent.

The above methods are used to prevent the rapid rise of the bearing temperature and alleviate the thermal deformation of the bearing to the greatest extent. However, as the speed continues to increase, the effect of mitigating the thermal deformation of the bearing through water cooling and bearing lubrication will gradually increase. At this time, in order to ensure the machining accuracy of the machine tool under the state of high rotational speed, the automatic bearing pretightening force adjustment mechanism 19 of the present invention will gradually take effect. As the speed increases, the cooling speed of water cooling and bearing lubrication can no longer catch up with the heating speed of the bearing. At this time, it is necessary to use a suitable bearing preload to offset the adverse effects of the thermal deformation of the bearing. First, the bearing is preloaded. The temperature sensor 52 in the force automatic adjustment mechanism 19 monitors the bearing temperature in real time, and feeds back the bearing temperature data detected in real time to the CNC system of the machine tool, and then outputs a control signal through the CNC system of the machine tool to make the elongation of the piezoelectric ceramic column 46 Changes are made to produce a suitable bearing preload and minimize the impact of thermal deformation of the bearing on the machining accuracy, thus ensuring the basic stability of the bearing support accuracy and ultimately providing a strong guarantee for the high-speed development of the machining center.

The solutions in the embodiments are not intended to limit the scope of patent protection of the present invention, and all equivalent implementations or changes that do not deviate from the present invention are included in the patent scope of this case.

Claims (1)

1. An ultrasonic electric spindle of a machining center with automatic adjustment of bearing pretightening force, characterized in that it includes a spindle, a housing, an upper end cover, a lower end cover, a rotor coil, and a stator coil; the rotor coil is fixedly set in the middle of the main shaft, The stator coil is fixedly installed on the inner surface of the casing, and a first cooling water jacket is installed between the stator coil and the casing, and a second cooling water jacket is installed on the outer surface of the casing at the axial position where the first cooling water jacket is located. The first spiral cooling water channel is provided in the first cooling water jacket, and the water inlet of the first spiral cooling water channel and the water outlet of the first spiral cooling water channel are both arranged on the shell; in the second cooling water jacket A second spiral cooling water channel is provided, and the water inlet of the second spiral cooling water channel and the water outlet of the second spiral cooling water channel are directly arranged on the second cooling water jacket; the water inlet of the first spiral cooling water channel, the first spiral cooling water channel Cooling water nozzles are installed on the water outlet, the water inlet of the second spiral cooling water channel and the water outlet of the second spiral cooling water channel; the upper end cover is fixed on the top of the shell, and the lower end cover is fixed on the bottom of the shell The barrel mouth, and an adapter sleeve is installed between the lower end cover and the housing, and the main shaft passes through the adapter sleeve and the lower end cover in turn and extends to the outside of the housing; the main shaft between the lower end cover and the rotor coil On the top, the first angular contact ball bearing, the first bearing lubricating sleeve and the second angular contact ball bearing are installed sequentially from bottom to top. The inner rings of the first angular contact ball bearing and the second angular contact ball bearing are in interference connection with the main shaft. The outer rings of the first angular contact ball bearing and the second angular contact ball bearing are interference-connected to the inner surface of the adapter sleeve through the first fixed sleeve of the outer ring of the bearing; on the main shaft above the rotor coil, they are installed sequentially from bottom to top There are rotor fastening nuts, third angular contact ball bearings, second bearing lubricating sleeves, fourth angular contact ball bearings, bearing pretightening force automatic adjustment mechanism and bearing axial limit nuts, third angular contact ball bearings and fourth angular contact ball bearings The inner ring of the ball bearing is in interference connection with the main shaft, the outer rings of the third angular contact ball bearing and the fourth angular contact ball bearing are in interference connection with the housing through the second fixed sleeve of the bearing outer ring, the second bearing lubricating sleeve and the bearing The pre-tightening force automatic adjustment mechanism is in interference connection with the second fixed sleeve of the bearing outer ring; the axial limit nut of the bearing is threadedly connected with the second fixed sleeve of the bearing outer ring; the main shaft is a hollow shaft in the center hole of the main shaft There is a pull rod, the top of the pull rod extends out of the upper hole of the main shaft, a pull rod axial limit nut is installed on the top of the pull rod, a disc spring is set on the top of the main shaft, and a force transmission sleeve is arranged between the pull rod axial limit nut and the disc spring tube; a hydraulic cylinder is installed on the lower surface of the upper end cover directly above the tie rod, the piston rod of the hydraulic cylinder is facing downward, and the piston rod of the hydraulic cylinder is set opposite to the top end of the tie rod; Generator, horn and handle locking mechanism, the handle locking mechanism is used in conjunction with the handle; a first lubricating oil channel is arranged in the first fixed sleeve of the outer ring of the bearing, and the adapter sleeve There is a second lubricating oil passage inside, the oil outlet end of the first lubricating oil passage communicates with the first bearing lubricating sleeve, the oil inlet end of the first lubricating oil passage communicates with the oil outlet end of the second lubricating oil passage, and the second The oil inlet end of the lubricating oil passage is equipped with a first lubricating oil nozzle; the electric spindle connection port is installed on the upper end cover; the third lubricating oil passage is arranged in the second fixed sleeve of the bearing outer ring, and the third The oil outlet end of the lubricating oil passage communicates with the second bearing lubricating sleeve, the fourth lubricating oil passage is opened on the housing, the oil inlet end of the third lubricating oil passage communicates with the oil outlet end of the fourth lubricating oil passage, The oil inlet end of the fourth lubricating oil passage is equipped with a second lubricating oil nozzle; an annular cooling water tank is also provided in the first fixed sleeve of the outer ring of the bearing, and an annular cooling water tank is respectively provided on the adapter sleeve The water inlet channel and the water outlet channel of the annular cooling water tank, and the angle between the water inlet channel of the annular cooling water tank and the water outlet channel of the annular cooling water tank is 180°; the automatic adjustment mechanism of the bearing pretightening force includes a piezoelectric ceramic column, a piezoelectric ceramic Column fixing seat, piezoelectric ceramic column radial positioning plate, first force transmission plate, spring, second force transmission plate and temperature sensor; piezoelectric ceramic column fixing seat, piezoelectric ceramic column radial positioning plate, first force transmission plate The disk and the second force transmission disk are both interference-connected on the second fixed sleeve of the bearing outer ring; the number of the piezoelectric ceramic columns is several, and the piezoelectric ceramic columns are uniformly arranged on the circumferential direction of the piezoelectric ceramic column fixing seat; A piezoceramic column positioning hole is opened on the radial positioning plate of the piezoelectric ceramic column, and the piezoelectric ceramic column passes through the positioning hole of the piezoelectric ceramic column and contacts with the first force transmission plate; the spring is connected to the first force transmission plate Between the second force transmission plate and the second force transmission plate, the second force transmission plate is in contact with the outer ring of the fourth angular contact ball bearing; the number of the springs is several, and the number of springs is between the first force transmission plate and the second force transmission plate. The temperature sensor is installed on the second force transmission plate, and the piezoelectric ceramic column adjusts the axial elongation through the temperature data fed back by the temperature sensor, and the bearing pre-setting is performed by adjusting the axial elongation of the piezoelectric ceramic column. Automatic adjustment of tension.

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