JPH1089355A - Preload control device for main spindle bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the preload of a main spindle bearing continuously variable. SOLUTION: An electromagnetic proportion pressure reducing valve 23 is provided for a line 25 feeding pressure oil to the preload chamber 28 of a main spindle bearing unit 27 from a pressure oil source 21. A numerical control part 42 corrects the target pressure based on the detected value from respective sensors 36 through 40. A digital controller 35 controls the electromagnetic proportion pressure reducing valve 23 by means of feedback operations in such a way that the pressure of the line 25, which is detected by a pressure 44, will be the corrected target pressure. Thus as mentioned above, the pressure of the line 25, that is, the preload to be applied to bearings 32 and 33 is so controlled that the main spindle bearing unit 27 is in the optimum operating condition at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preload control device for a spindle bearing which continuously and optimally controls the preload applied to a spindle bearing of a machine tool or the like.

[0002]

2. Description of the Related Art A spindle bearing of a machine tool is operated by applying a preload so as to have high rigidity without rattling. Such a preload variable spindle unit is shown in FIG.
No. 6034). When the spindle in the variable preload spindle unit is rotated at a high speed, the bearing expands due to heat generation, and if left untreated, seizure occurs and locks. Thus, in the variable preload spindle unit, as shown in FIGS. 3 (a) to 3 (c),
The preload can be switched in three stages.

FIG. 3A shows a state in which the operation is stopped or a minimum preload is performed, and no pressure oil is supplied to the first preload chamber 1 and the second preload chamber 2. Therefore, the bearing housing 3 and the intermediate ring 4
A gap d ₁ is formed in a first step portion 7 a of a movement amount control ring 7 which is located on a side of a first preload chamber 1 and is fixed to an outer cylinder 5 via a positioning flange 6. clearance d ₂ is formed on the stepped portion 7b. Then, a deviation d ₃ occurs between the outer ring and the inner ring of the bearing 8. Thus, bearings 8,9 with minimal force
Is preloaded. The above three gaps d ₁ , d ₂ , d ₃
The relationship is as follows. d _2> d _1> d ₃

FIG. 3 (b) shows a state of medium preload, in which pressure oil is supplied to the first preload chamber 1 from a pressure oil passage. Then, the intermediate ring 4 is moved to the first step portion 7a of the movement amount control ring 7.
And the bearing ring 3 is pressed by the intermediate ring 4. In this way, the outer rings of the bearings 8 and 9 are preloaded through the spacers 10 and 11 with a greater force than in the case of FIG. Preload in this case is (d ₁ -d _3).

FIG. 3 (c) shows a state of maximum preload, in which pressure oil is supplied to the second preload chamber 2 from a pressure oil passage. On the other hand, the pressure oil in the first preload chamber 1 is discharged. Then, the bearing box 3 is pressed until the step 3a of the bearing box 3 comes into contact with the second step 7b of the movement amount control ring 7, and the spacers 10 and 11 are applied with a larger force than in the case of FIG. Thus, the outer rings of the bearings 8 and 9 are preloaded. Preload in this case is (d ₁ -d _3).

[0006]

However, in the above-mentioned conventional preload variable spindle unit, the pressurized oil is switched between the first preload chamber 1 and the second preload chamber 2 and supplied to the outer rings of the bearings 8 and 9. Since the preload is changed, the preload is switched stepwise. Therefore, the above 3
There is a problem that the preload cannot be applied with a force other than the preload at the stage. Further, there is also a problem that high-speed machining cannot be continuously performed because a sudden change occurs in the preload at the time of switching.

The setting of the three stages of preload is performed by the amount of movement of the bearing housing 3 and the intermediate ring 4. Therefore, the dimensions of the _three distances d ₁ , d ₂ , and d ₃ must be set accurately. Therefore, it is necessary to tighten the mechanical tolerance of each part, which causes a problem that the cost of the spindle unit is increased.

In recent years, machine tools have been required to perform high-precision and high-precision machining. Accordingly, a wide range of control from a very low speed to a very high speed has been required for the machining speed. There is a demand for continuously variable control up to high pressure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a main shaft bearing preload control device capable of continuously changing the main shaft bearing preload.

[0010]

In order to achieve the above object, the present invention is directed to a pressure control valve interposed in a line for supplying pressure oil to a preload means of a spindle bearing unit, and a spindle bearing. Target pressure setting means for setting a target pressure of the line corresponding to the preload applied to the sensor, a sensor for detecting an operating state of the spindle bearing unit, and correcting and correcting the target pressure according to an output of the sensor. It is characterized by comprising target pressure correcting means for outputting a target pressure, and pressure control means for controlling the operation of the pressure control valve based on the corrected target pressure.

According to the above configuration, the operation of the pressure control valve is controlled by the pressure control means, and the preload applied to the main shaft bearing is set continuously from an extremely low pressure to a high pressure.
Further, the pressure control means controls an operation of the pressure control valve based on a corrected target pressure corrected according to an operation state of the main shaft bearing unit. Therefore, the operating state of the spindle bearing unit is optimized,
A preload is applied to the spindle bearing.

According to a second aspect of the present invention, there is provided the main shaft bearing preload control device according to the first aspect of the present invention, further comprising a pressure sensor for detecting a pressure of the line.
The pressure control means feedback-controls the pressure control valve so that the pressure detected by the pressure sensor becomes the corrected target pressure.

According to the above configuration, feedback control is performed so that the pressure in the line becomes the corrected target pressure, and the preload applied to the main shaft bearing is accurately controlled based on the corrected target pressure.

According to a third aspect of the present invention, in the main shaft bearing preload control device according to the first aspect of the present invention, the sensor is a vibration sensor that detects vibration of the main shaft, and the target pressure correcting means is The difference between the output of the vibration sensor and the vibration set value is determined, and the target pressure is corrected according to the difference value.

According to the above configuration, a preload is applied to the main shaft bearing in accordance with the difference between the main shaft vibration and the set value so that the main shaft does not vibrate.

According to a fourth aspect of the present invention, in the preload control device for a spindle bearing according to the first aspect of the present invention, the sensor is a position sensor for detecting a relative position of inner and outer rings of the spindle bearing, The target pressure correcting means determines a difference between the output of the position sensor and a position set value, and corrects the target pressure according to the value of the difference.

According to the above configuration, the relative position of the inner and outer wheels of the main shaft bearing is set to a position exhibiting an optimum preload in accordance with the difference between the relative position of the inner and outer rings of the main shaft bearing and the set value. The line pressure is controlled.

According to a fifth aspect of the present invention, in the preload control device for a spindle bearing according to the first aspect of the present invention, the sensor is a rotation speed sensor for detecting a rotation speed of the main shaft, The correction means is characterized in that a difference between the output of the rotation speed sensor and the rotation speed set value is obtained, and the target pressure is corrected according to the difference value.

According to the above configuration, an optimum preload corresponding to the rotation speed of the spindle is applied to the spindle bearing according to the difference between the rotation speed of the spindle and the set value.

According to a sixth aspect of the present invention, in the main shaft bearing preload control device according to the first aspect of the present invention, the sensor is a load sensor for detecting a load of an electric motor that rotationally drives the main shaft, The target pressure correcting means is
A difference between the load sensor and a load set value is obtained, and the target pressure is corrected according to the value of the difference.

According to the above configuration, the pressure in the line is controlled according to the difference between the load of the spindle motor and the set value so that abnormal preload is not applied to the spindle bearing.

According to a seventh aspect of the present invention, in the preload control apparatus for a spindle bearing according to the first aspect of the present invention, the sensor is a temperature sensor for detecting a temperature of the spindle bearing, and The means is characterized in that a difference between an output of the temperature sensor and a temperature set value is obtained, and the target pressure is corrected according to the value of the difference.

According to the above configuration, a preload is applied to the spindle bearing according to the difference between the temperature of the spindle bearing and its set value so that the temperature of the spindle bearing does not become an abnormal temperature.

According to an eighth aspect of the present invention, in the preload control device for a spindle bearing according to the first aspect of the present invention, the preload control device is provided on the line between the pressure control valve and the preload means, A pilot-operated on-off valve that opens the side pressure as a pilot pressure is provided.

According to the above construction, while the workpiece is being machined while a preload is applied to the spindle bearing, the pilot-operated on-off valve and the above-described valve are caused by an abnormality in the pressure oil source or the pressure control valve, a broken pipe, or the like. When the pressure between the pressure control valve and the pressure control valve suddenly decreases, the pressure on the primary side of the pilot operated on-off valve decreases. Therefore, the pilot-operated on-off valve is closed, and the pressure oil is prevented from leaking from the preload means.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a hydraulic circuit diagram and a control block diagram of a main shaft bearing preload control device according to the present embodiment. Pressure oil from the pressure oil source 21 is supplied to the main shaft 2 by a line 25 in which a check valve 22, an electromagnetic proportional pressure reducing valve 23 and a pilot operated check valve 24 are sequentially provided.
6 is supplied to the preload chamber 28 of the spindle bearing unit 27 which receives a load in the thrust direction. Then, a preload is applied to the outer rings of the bearings 32 and 33 as the main shaft bearings via the slider 29 and the inner and outer ring spacers 30 and 31 by the pressure oil.

The pressure in the line 25 is set as follows by an electromagnetic proportional pressure reducing valve 23 whose operation is controlled by a control signal from the digital controller 35.

The numerical control unit 42 selects a machining condition conforming to the work specification from the database 43 based on the work specification such as the material, thickness and length of the work input from the input unit (not shown). To set. Then, according to the set processing conditions, the target pressure of the line 25 and the spindle 26
From the database 43, the vibrations, the positions of the outer rings of the bearings 32 and 33, the load of the electric motor 41, and the set values that determine the respective limit values of the temperatures of the bearings 32 and 33 are obtained. Then, it outputs a pressure command signal representing the obtained target pressure of the line 25 to the digital controller 35, and subsequently outputs a start command signal.

Then, the digital controller 35 receives the start command signal from the numerical control unit 42, and receives the start command signal from the numerical controller 42, based on the pressure signal from the pressure sensor 44.
A control signal corresponding to the differential pressure between the pressure of the solenoid valve and the target pressure from the numerical controller 42 is transmitted to the solenoid 23a of the electromagnetic proportional pressure reducing valve 23.
Output to In this way, the electromagnetic proportional pressure reducing valve 23 is controlled to an opening degree corresponding to the current of the control signal, and the line 25 is controlled.
Is set to the target pressure.

As described above, the digital controller 35 performs feedback control so that the pressure in the line 25 becomes the target pressure, and the pressure in the preload chamber 28 becomes the target pressure. Then, the slider 29
As a result, a preload is applied to the outer races of the bearings 32 and 33, causing a positional shift between the outer races and the inner races. The main shaft 26 is rotated with high rigidity without rattling, and machining of the workpiece is started.

If the work is processed in this state, the work will eventually generate heat due to the cutting friction and the bearing 3
The temperature of 2,33 rises. The temperature rise of the bearings 32 and 33 is detected by the temperature sensor 40. Further, the vibration generated in the main shaft 26 is detected by the vibration sensor 36. Further, the positions of the outer rings of the bearings 32 and 33 to which the preload is applied are detected by the position sensor 37. The rotation speed of the main shaft 26 is detected by a rotation speed sensor 38.
Further, the load of the electric motor 41 is detected by the load sensor 39.

The numerical controller 42 calculates the difference between each value detected based on the signals from the sensors 36 to 40 and its set value. Then, based on the value of the calculated difference, the temperatures of the bearings 32 and 33, the vibration of the main shaft 26, the bearing 3
When any one of the position of the outer ring 2 · 33, the rotation speed of the main shaft 26, and the load of the electric motor 41 reaches the set value, the target pressure is corrected downward by a predetermined pressure. Then, a pressure command signal representing the corrected target pressure is output to the digital controller 35 to reduce the preload on the spindle bearing unit 27. In this way, the operation state of the main shaft bearing unit 27 is monitored, and the pressure in the line 25 is continuously controlled so that the optimum preload is applied to the bearings 32 and 33.

Here, as described above, the bearings 32, 3
While the workpiece is being machined by applying a preload to 3, the pressure in the line 25 may be released due to, for example, a failure of the electromagnetic proportional pressure reducing valve 23 or a broken pipe.
However, even in this case, the pilot-operated check valve 24 that opens the primary-side pressure as the pilot pressure is interposed in the line 25. Therefore, when the primary-side pressure decreases, the pilot-operated check valve is reduced. This prevents the pressure oil in the preload chamber 28 from leaking out due to the closure of the pressure chamber 24.

FIG. 2 shows the digital controller 35.
It is a block diagram of a structure of. The signal input unit 45 receives a pressure command signal, a start command signal, and an alarm reset signal from the numerical control unit 42. Pressure sensor input section 46
Receives a pressure signal from the pressure sensor 44. The valve drive unit 47 outputs the control signal to the solenoid 23a of the electromagnetic proportional pressure reducing valve 23. The signal output unit 48 outputs an alarm signal and a completion signal to the numerical control unit 42.

Based on the signal input from the signal input unit 45, the arithmetic control unit 49 instructs the signal output unit 48 to stop outputting the alarm signal if the signal is an alarm reset signal, Stores the target pressure represented by the pressure command signal in the register. Further, in the case of the start signal, the difference between the pressure of the line 25 based on the pressure signal received at the pressure sensor input section 46 and the target pressure stored in the register is calculated, and the opening degree of the electromagnetic proportional pressure reducing valve 23 is calculated. Is instructed to the valve drive unit 37 to make the opening degree corresponding to the pressure difference. Further, when the pressure in the line 25 becomes abnormal, a signal output unit 48 is instructed to output an alarm signal. When the pressure of the line 25 falls within the allowable range centered on the target pressure, the signal output unit 48 is instructed to output a completion signal indicating that the pressure setting of the line 25 has been completed.

As described above, in the present embodiment, the electromagnetic proportional pressure reducing valve 23 is provided in the line 25 for supplying the pressure oil from the pressure oil source 21 to the preload chamber 28 of the main shaft bearing unit 27. Then, the digital controller 35 performs feedback control so that the pressure of the line 25 detected by the pressure sensor 44 becomes the target pressure set by the numerical controller 42. Therefore, the optimum preload to the bearings 32 and 33 can be set steplessly according to the processing conditions of the work. That is, according to the present embodiment, it is possible to precisely control the preload to the bearings 32 and 33 at an extremely low pressure, and to perform high-speed precision machining of the work.
On the other hand, during low-speed machining, a high preload can be applied, and the rigidity of the machine tool can be increased.

The numerical control unit 42 controls the vibration of the main shaft 26, the positions of the outer rings of the bearings 32 and 33, the rotation speed of the main shaft 26, the load of the electric motor 41, and the temperatures of the bearings 32 and 33 and the set values. The target pressure is corrected according to the difference between the target pressure and the target pressure. Therefore, the spindle bearing unit 2
7, the operation state of the spindle bearing unit 27 is monitored.
A preload can be applied to the bearings 32 and 33 so that the operation state of the bearings is optimized. That is, according to the present embodiment, the life of the bearings 32 and 33 can be extended. In addition, high-precision processing can be performed by suppressing heat generation of the bearings 32 and 33. Further, the starting torque and the friction energy can be reduced by suppressing unnecessary preload, and the running cost of the machine can be reduced. Further, unlike the conventional variable preload spindle shown in FIG. 3, the mechanical tolerances are not strict and the adjustment work does not require much time, so that the cost of the spindle bearing unit 27 can be reduced.

The electromagnetic proportional pressure reducing valve 23 may be a 3-port 2-position electromagnetic proportional switching valve. The pilot operated check valve 24 has a normal position in which the primary side is closed between the primary side and the secondary side, and an offset position in which the primary side and the secondary side communicate with each other using the primary side pressure as a pilot pressure. And a pilot operated two-position switching valve having the following. Further, the shape and arrangement of the preload means constituted by the preload chamber 28 and the slider 29 are not limited to those in the above-described embodiment. Good.

In the above embodiment, the digital controller 35 feeds back the electromagnetic proportional pressure reducing valve 23 so that the pressure in the line 25 based on the pressure signal from the pressure sensor 44 becomes the target pressure (corrected target pressure). Although the present invention is controlled, the present invention is not limited to this. For example, the pressure of the line 25 is changed to the target pressure.
(Corrected target pressure) Current value and target pressure of the above control signal
(Corrected target pressure) and store it in the internal memory of the digital controller 35. When the digital controller 35 receives the pressure command signal from the numerical controller 42, the digital controller 35 refers to the internal memory to set the opening of the electromagnetic proportional pressure reducing valve 23 to a target pressure (corrected target pressure) represented by the pressure command signal. A control signal for setting the opening according to the control signal may be obtained, and the control signal may be supplied to the solenoid 23a.

In the above embodiment, the means for detecting the operating state of the spindle bearing unit 27 includes the vibration sensor 36, the position sensor 37, and the rotation speed sensor 3.
8, the load sensor 39 and the temperature sensor 40 are provided, but only necessary sensors among the sensors 36 to 40 may be appropriately selected and used. In addition, each of the sensors 3
It is not limited to only 6 to 40, for example, bearing 3
A sensor for detecting a load of 2,33 may be used.

[0041]

As apparent from the above description, the preload control device for a spindle bearing according to the first aspect of the present invention has a pressure control valve interposed in a line for supplying pressurized oil to preload means of the spindle bearing unit. Since the operation of the pressure control valve is controlled by the control means, the preload applied to the spindle bearing can be set in a stepless manner from an extremely low pressure to a high pressure, and an optimum preload can be set according to the processing conditions of the work. Therefore, according to the present invention, it is possible to precisely control the preload applied to the spindle bearing at an extremely low pressure, and to perform high-speed precision machining of a work. Also, high rigidity can be achieved by high preload during low-speed machining.

Further, the pressure control means performs the control based on the corrected target pressure corrected by the target pressure correction means in accordance with the operation state of the spindle bearing unit detected by the sensor. By monitoring the condition, a preload can be applied to optimize the operating condition of the spindle bearing unit. Therefore, according to the present invention, the life of the spindle bearing can be extended. Further, the running cost can be reduced by suppressing useless preload. Further, unlike the conventional variable preload spindle shown in FIG. 3, it is not necessary to tighten the mechanical tolerance, so that the cost can be reduced.

The pressure control means in the main shaft bearing preload control device according to the second aspect of the invention controls the pressure control so that the pressure detected by the pressure sensor for detecting the pressure of the line becomes the corrected target pressure. Since the valve is feedback-controlled, the preload applied to the spindle bearing can be accurately controlled based on the corrected target pressure.

Further, in the apparatus for controlling preload of a spindle bearing according to the third aspect of the present invention, the sensor is a vibration sensor for detecting a vibration generated in the spindle, and the target pressure correcting means is configured to detect the vibration of the spindle and its setting. Since the target pressure is corrected according to the value of the difference from the value, a preload can be applied to the spindle bearing so that abnormal vibration does not occur in the spindle.

In the apparatus for controlling preload of a spindle bearing according to a fourth aspect of the present invention, the sensor is a position sensor for detecting the relative position of the inner and outer races of the spindle bearing, and the target pressure correcting means is provided for the spindle bearing. Since the target pressure is corrected in accordance with the value of the difference between the relative position of the inner and outer rings and the set value, the pressure of the line is controlled so that the relative position of the inner and outer rings of the main shaft bearing becomes a position exhibiting an optimal preload. it can.

In the apparatus for controlling preload of a spindle bearing according to a fifth aspect of the present invention, the sensor is a rotation number sensor for detecting the rotation number of the spindle, and the target pressure correcting means is configured to determine the rotation number of the spindle. Since the target pressure is corrected according to the value of the difference from the set value, an optimal preload corresponding to the rotation speed of the spindle can be applied to the spindle bearing.

The sensor in the preload control device for a spindle bearing of the invention according to claim 6 is a load sensor for detecting a load on an electric motor that rotationally drives the spindle.
Since the target pressure correcting means corrects the target pressure according to the value of the difference between the load of the electric motor and its set value, the pressure in the line can be controlled so that an abnormal preload is not applied to the main shaft bearing.

Further, in the apparatus for controlling the preload of a spindle bearing according to the present invention, the sensor is a temperature sensor for detecting the temperature of the spindle bearing, and the target pressure correcting means includes the temperature of the spindle bearing and the temperature of the spindle bearing. Since the target pressure is corrected according to the difference from the set value, a preload can be applied to the spindle bearing so that the temperature of the spindle bearing does not become abnormal. Further, high-precision machining can be performed by suppressing the heat generation of the spindle bearing.

Further, the preload control device for a spindle bearing according to the present invention is characterized in that a pilot-operated on-off valve for releasing the pressure on the primary side as pilot pressure between the pressure control valve of the line and the preload means. If the pressurized oil is released from the line while the workpiece is being machined by applying a preload to the main shaft bearing, the pilot-operated on-off valve closes and the preload means The escape of the pressure oil is prevented. Therefore, the work can be processed safely.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram and a control block diagram of a main shaft bearing preload control device of the present invention.

FIG. 2 is a block diagram showing a configuration of a digital controller in FIG.

FIG. 3 is an explanatory diagram of preload switching in a conventional preload variable spindle unit.

[Explanation of symbols]

21: pressure oil source, 23: electromagnetic proportional pressure reducing valve, 24: pilot operated check valve, 25: line, 26: spindle, 27: spindle spindle unit, 28: preload chamber,
32, 33 ... bearing, 35 ... digital controller,
36: vibration sensor, 37: position sensor,
38: rotation speed sensor, 39: load sensor,
40: temperature sensor, 41: electric motor,
42 Numerical control unit, 43 Database.

Claims (8)

[Claims] 1. A pressure control valve (23) interposed in a line (25) for supplying pressure oil to preload means (28, 29) of a main shaft bearing unit (27), and a main shaft bearing (32, 33). Target pressure setting means (42) for setting a target pressure of the line (25) corresponding to the preload to be applied; sensors (36 to 40) for detecting an operating state of the spindle bearing unit (27); Target pressure correcting means for correcting the target pressure according to the output of (36-40) and outputting a corrected target pressure
(42) and a pressure control means (35) for controlling the operation of the pressure control valve (23) based on the corrected target pressure. 2. The preload control device for a spindle bearing according to claim 1, further comprising a pressure sensor (44) for detecting a pressure of said line (25), and wherein said pressure control means (35) includes: (44) so that the pressure detected by (44) becomes the corrected target pressure,
A preload control device for a spindle bearing, wherein the pressure control valve (23) is feedback-controlled. 3. The preload control device for a spindle bearing according to claim 1, wherein said sensor detects a vibration of said spindle.
(36), wherein the target pressure correcting means (42) is the vibration sensor (36).
A preload control device for a spindle bearing, wherein a difference between an output of the main shaft and a vibration set value is obtained, and the target pressure is corrected according to the value of the difference. 4. The preload control device for a spindle bearing according to claim 1, wherein the sensor is a position sensor (37) for detecting a relative position of an inner and an outer ring of the spindle bearing (32, 33). The target pressure correcting means (42) is provided with the position sensor (37).
A preload control device for a spindle bearing, wherein a difference between the output of the main shaft and a position set value is obtained, and the target pressure is corrected according to the value of the difference. 5. The main shaft bearing preload control device according to claim 1, wherein the sensor is a rotation speed sensor (38) for detecting a rotation speed of the main shaft (26), and the target pressure correcting means (38). 42) is the rotation speed sensor (3)
A preload control device for a spindle bearing, wherein a difference between the output of (8) and the set value of the number of revolutions is obtained, and the target pressure is corrected according to the value of the difference. 6. The preload control device for a spindle bearing according to claim 1, wherein the sensor rotates the spindle (26).
(41) a load sensor (39) for detecting a load, wherein the target pressure correcting means (42) is a load sensor (39);
And a load setting value. The preload control device for a spindle bearing, wherein the target pressure is corrected according to the difference value. 7. The main shaft bearing preload control device according to claim 1, wherein said sensor is a temperature sensor (40) for detecting a temperature of said main shaft bearing (32, 33), and said target pressure correcting means. (42) The temperature sensor (40)
A preload control device for a spindle bearing, wherein a difference between an output of the main shaft and a temperature set value is obtained, and the target pressure is corrected according to the value of the difference. 8. The preload control device for a spindle bearing according to claim 1, wherein said preload control device is provided in said line (25) between said pressure control valve (23) and preload means (28, 29). Pilot operated on-off valve (2
A preload control device for a spindle bearing, comprising: