JP2002126910A - Main spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a main spindle device capable of reliably preventing the occurrence of an accident, such as seizure of a bearing, by rapidly and reliably detecting shortage of a feed of lubricating oil when reduction of a lubrication oil feed amount occurs. SOLUTION: In the main spindle device 1 using an ultramicro oil lubrication system lubricating device 110 to feed lubricating oil, discharged by an ultramicro lubricating oil pump 5, through a nozzle 20 to a lubrication spot in a feed of lubricating oil to rolling bearings 16 and 17 supporting a main spindle 15 a lubrication abnormality detecting means 120 is provided to detect abnormality of a feed state of lubricating oil to the rolling bearings 16 and 17 when the fluctuation width of the drive force of an electric motor 23 right after shot of lubricating oil deviated from a standard range by monitoring the drive force of the electric motor 23 to rotationally drive the main spindle 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spindle device for various high-speed rotating machines such as machine tools.

[0002]

2. Description of the Related Art Conventionally, lubricating devices such as an oil mist system, an oil air system, and a jet system are generally used for lubricating a bearing for a high-speed rotating spindle. However, as the current trend, a higher speed of the spindle device is required, and in the conventional lubricating device described above, with respect to the higher speed of the spindle device,
The following problems occur.

[0003] First, the case of the lubricating device of the oil mist method, the bearing is affected by an air curtain becomes high-speed rotation, d _m · N 2,000,000 (however, d _m is the pitch circle of the bearing Above the diameter (unit: mm) and N is the rotational speed of the bearing (unit: rpm), lubricating oil is hardly supplied into the inside of the bearing, and there is a possibility that the bearing may seize.

On the other hand, in the case of the oil-air system, it is difficult to continuously and stably supply a small amount of lubricating oil. Therefore, it is necessary to intermittently supply the lubricating oil, and the lubricating oil must be supplied at regular intervals (for example, every 8 to 16 minutes). Amount (usually 0.01 to 0.03 cc (m
l)) The lubricating oil is supplied into the air pipe. For this reason, the amount of lubricating oil supplied to the bearing changes with time, and as a result, the lubrication state inside the bearing changes constantly, especially since the lubricating oil is large in the bearing immediately after the lubricating oil is supplied. This causes a phenomenon that the bearing torque and the bearing temperature fluctuate. This phenomenon may cause a decrease in processing accuracy in, for example, a machine tool.

In the case of a jet type lubrication device,
The influence of the air curtain described above is hardly affected compared to the oil mist and oil-air systems. However, an additional device including a high-pressure pump is required, and the agitation resistance on the shaft side due to an increase in the amount of oil supplied to the bearing is required. Due to the increase, a large motor having a large driving force is required for the motor for driving the main shaft, which increases the cost.

In order to solve such a problem, the applicant of the present application has already proposed a lubricating device 100 of an ultra-micro oil lubrication system shown in FIG. Lubricating device 100 shown here
Is disclosed in Japanese Unexamined Patent Publication No. 2000-110711, in which lubricating oil discharged from the ultra-small amount lubricating oil pump 5 whose operation is controlled by the control device 6 is supplied via a pipe 38 serving as a lubricating oil supply path. It is guided to the nozzle and injected directly from the nozzle to the lubrication point.

The micro-amount lubricating oil pump 5 slides a lubricating oil introduced from a lubricating oil tank (not shown) into a pump chamber 37 via a lubricating oil conveying pipe 41 inside a cylinder 36 in the pump chamber 37. The reciprocating piston 35 discharges the lubricating oil to a pipe 38 serving as a lubricating oil supply path.
1 is connected to the suction port 39 of the pump chamber 37 communicating with the pump chamber 3.
A suction valve (return valve) 40 for preventing backflow from the lubricating oil transfer pipe 41 side to the lubricating oil transfer pipe 41 is provided, and the reciprocating operation of the piston 35 is performed by the expansion and contraction operation of the rod 30.

The rod 30 is a giant magnetostrictive element having a positive characteristic which extends in the axial direction by applying a magnetic field. The magnetic field is applied to the rod 30 by applying a current to a coil 43 mounted concentrically around the rod 30. It is performed by application. The current applied to the coil 43 is
The control device 6 controls according to the required discharge amount. That is, the control device 6 controls the piston 35 by the extension of the rod 30.
The supply current to the coil 43 is controlled so that the application of the magnetic field from the coil 43 to the rod 30 is controlled so that the required discharge amount for one shot is obtained by the displacement.

When the lubricating device 100 is used, compressed air is not used to supply the lubricating oil, so that trace oil lubrication or ultra-trace oil lubrication can be easily and accurately realized. It is also possible to prevent torque fluctuations on the shaft side due to intermittent supply, and to improve the rotational performance of the spindle by using it for lubrication of the bearing portion of the spindle that rotates at high speed.

[0010]

However, in the case of using a minute amount of oil lubrication or an ultra minute amount of oil lubrication, if the actual amount of lubricating oil supply is insufficient than expected for some reason,
Problems such as seizure of the rolling bearing supporting the main shaft and significant deterioration of the rotational performance of the main shaft are likely to occur. Therefore, when a minute amount of oil lubrication or a very small amount of oil lubrication is used for lubricating the bearing portion of the main shaft rotating at high speed, it is indispensable to provide a lubrication abnormality detecting means for quickly detecting a decrease in the amount of supplied lubricating oil. .

Therefore, it has been proposed to equip the aforementioned ultra-micro lubricating oil pump 5 itself with lubrication abnormality detecting means for detecting a decrease in the lubricating oil supply amount. However, in order to incorporate the lubrication abnormality detecting means into the ultra-trace lubricating oil pump 5 itself, many parts constituting the ultra-trace lubricating oil pump 5 need to be modified, which causes a problem of cost increase. In addition, inconveniences such as a decrease in the amount of lubricating oil supplied to the lubricating point occur not only due to the failure of the pump itself, but also due to clogging of the nozzle and clogging of the pipe from the pump to the nozzle,
In the case where the lubricating oil supply amount is reduced due to a cause other than the failure of the pump, there is a possibility that the occurrence of an abnormality such as insufficient lubricating oil supply may be overlooked by incorporating the lubricating abnormality detecting means into the ultra-small amount of lubricating oil pump 5 itself.

The present invention has been made in view of the above circumstances, and is not limited to the failure of the pump itself. If the supply of lubricating oil is reduced for some reason, the shortage of the amount of lubricating oil supplied is detected quickly and reliably. It is possible to reliably prevent accidents such as bearing seizure caused by overlooking an abnormality such as insufficient lubricating oil supply, and furthermore, remodeling is required to detect insufficient lubricating oil supply. Since the number of existing components is small, the cost of improvement is low, and therefore, the improvement of the reliability of the lubrication performance can improve the rotation performance of the spindle device and the life of the bearing, and at the same time,
It is an object of the present invention to provide a spindle device capable of reducing manufacturing costs.

[0013]

According to a first aspect of the present invention, there is provided a spindle device, comprising: a spindle; a housing through which the spindle is inserted; and a plurality of spindles spaced apart in an axial direction of the spindle. A rolling bearing rotatably supported by the housing; a shaft driving unit that drives the main shaft to rotate at a high speed by an electric motor; and a lubricating device for supplying lubricating oil to the rolling bearing. A nozzle for injecting oil toward a predetermined portion of the rolling bearing, a lubricating oil pump for intermittently discharging lubricating oil with an extremely small discharge amount, and a lubricating oil which is supplied by the lubricating oil pump. And a lubricant oil supply passage for guiding the lubricant oil to the nozzle at a discharge speed of the lubricant oil from the nozzle in a range of 13 to 200 m / sec and a discharge oil amount of 0.0008 to 0.01 cc per shot.
In the spindle device for intermittently supplying the lubricating oil having a range of (ml), the driving force of the electric motor is monitored, and the fluctuation range of the driving force of the electric motor immediately after the lubricating oil shot is out of a standard range. In this case, lubrication abnormality detecting means for detecting an abnormality in the supply state of the lubricating oil to the rolling bearing is provided.

In the above-described spindle device, when lubricating oil is injected from the nozzle into the inside of the rolling bearing, the injected lubricating oil increases the frictional resistance of the rolling elements in the rolling bearing, so that the dynamic torque of the rolling bearing increases. . This phenomenon of increase in dynamic torque has a degree of increase corresponding to the amount of lubricating oil injected into the rolling bearing, and also depends on the degree of increase in dynamic torque of the rolling bearing in accordance with the driving force of the electric motor driving the main shaft. Brings fluctuation. Therefore, if the lubricating oil supply amount decreases for any reason, such as a failure of the lubricating oil pump constituting the lubricating device or clogging of the nozzle, the driving force of the electric motor driving the main shaft is eventually reduced. According to the above-described configuration in which the fluctuation state of the driving force of the electric motor is monitored by the lubrication abnormality detecting means in order to realize as a phenomenon in which the fluctuation amount is reduced, even if the lubricating oil supply amount is reduced for any reason, it is quick and reliable. This can be detected.

In the above-described spindle device, the driving force of the electric motor monitored by the lubrication abnormality detecting means corresponds to, for example, power consumption of the electric motor, load torque, or driving current. Whether to use power consumption, or load torque, or drive current as the driving force is preferably, in consideration of existing facilities and environment, for example,
It is preferable to select one that reduces the burden on equipment costs. By selecting the driving force of the electric motor monitored by the lubrication abnormality detecting means in this way, the degree of freedom in designing the lubrication abnormality detecting means is improved.

Preferably, in the above spindle device, the monitoring of the driving force of the electric motor by the lubrication abnormality detecting means is performed from about 10 seconds before the shot to about 10 seconds immediately after the shot with reference to the shot timing of the lubricating oil by the nozzle. The time period within one second is defined as the monitoring period. For example, the fluctuation range of the driving force is calculated by comparing the maximum driving force between the monitoring time period before the shot and the monitoring time period immediately after the shot. If it exceeds the width, it may be determined that lubricating oil supply is abnormal. In the ultra-micro oil lubrication system, since the amount of lubricating oil injected is very small, the rise in bearing torque due to the lubricating oil shot returns to the normal value in about 1 second immediately after injection, so subsequent monitoring is , Not so useful data. Generally, in the ultra-micro oil lubrication method, the shot interval is set to an appropriate value, for example, 60 seconds / shot or 120 seconds / shot, and lubricating oil is supplied intermittently. By limiting the band, accumulation of unnecessary data can be minimized, only useful data can be monitored efficiently, and the amount of recorded data can be reduced.

More preferably, for example, when the spindle device is for a machine tool, and the work to be contacted with the spindle has conductivity, the spindle and the work are brought into contact with each other. It is preferable that the state where the main shaft and the workpiece are not short-circuited is detected by detecting the electrical short-circuit state between the two and detecting the electrical short-circuit state therebetween, and monitoring by the lubrication abnormality detecting means. Generally, in a machine tool, the time during which the spindle is rotationally driven in a non-cutting state (that is, a state in which the spindle and the workpiece are not in contact with each other) often occupies several tens% or more. By operating the lubrication abnormality detecting means in the belt, the reliability of detecting the lubricating oil supply abnormality can be improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a spindle device according to the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a configuration of a spindle device according to a first embodiment of the present invention. The spindle device 1 according to the first embodiment includes a main shaft 15, a housing 18 through which the main shaft 15 is inserted horizontally, and rolling that rotatably supports the main shaft 15 on the housing 18 at a plurality of locations spaced apart in the axial direction. Bearings 16 and 17, and a shaft drive unit 25 that drives the main shaft 15 to rotate at high speed by an electric motor 23.
And a lubricating device 110 for supplying lubricating oil to the rolling bearings 16 and 17 and a driving force of the electric motor 23 via the shaft driving unit 25 to monitor the electric motor 23 immediately after the lubricating oil shot.
The lubrication abnormality detecting means 120 for detecting an abnormality in the supply state of the lubricating oil to the rolling bearings 16 and 17 when the fluctuation range of the driving force exceeds the standard range, and the driving of the electric motor 23 monitored by the lubrication abnormality detecting means 120 And a pen recorder 27 for recording a force on a predetermined sheet.

The rolling bearing 16 comprises a front portion 15a of the main shaft 15.
Are rotatably supported, and the rolling bearing 17 is an angular ball bearing that rotatably supports the rear portion 15b of the main shaft 15. The outer rings of the rolling bearings 16 and 17 are fitted on the inner periphery of the cylindrical portion 18a of the housing 18 and the sleeve 18b is fitted on the inner periphery of the cylindrical portion 18a.
And presser lids 18d, 18 provided at both ends of the cylindrical portion 18a.
The movement in the axial direction is regulated by e.

The inner rings of the rolling bearings 16, 17 are
Along with the outer periphery of the main shaft 15, the movement in the axial direction is restricted by the sleeve 18 c fitted on the outer periphery of the main shaft 15 and the holding rings 21 a and 21 b provided at both ends of the main shaft 15. The press ring 21a is pressed toward the rolling bearing 16 by a press nut 22a screwed into the front portion 15a of the main shaft 15. In addition, the holding ring 21b
Axial positioning is performed by contacting a flange 15c provided on a rear portion 15b of the main shaft 15.

The above-described mounting structure allows each of the rolling bearings 16 and 17 to freely rotate relative to each other between the inner and outer rings. Although the main shaft 15 in the present embodiment is supported in a posture in which the axial direction is horizontal, for example, when used in a machining center, it may be used vertically or inclined.

As shown in FIG. 2, the lubricating device 110
A nozzle 20 (see FIG. 1) for injecting lubricating oil toward predetermined portions of the rolling bearings 16 and 17, a lubricating oil tank 2 storing lubricating oil 25, and lubrication supplied from the lubricating oil tank 2 0.0008 oil 25 per shot
An ultra-small amount lubricating oil pump 5 capable of intermittent discharge at a discharge amount in the range of 0.01 cc (ml), a lubricating oil filter 3 for filtering lubricating oil 25 stored in a lubricating oil tank 2, and a lubricating oil An air bleeding device 4 that is provided in an oil supply pipe from the tank 2 to the micro-lubricating oil pump 5 and discharges air mixed in the lubricating oil, and guides the lubricating oil discharged from the ultra-micro-lubricating oil pump 5 to the nozzle 20. The configuration includes a lubricating oil supply path 130 and a control device 61 for controlling the operation of the ultra-trace lubricating oil pump 5. The control device 61 outputs to the lubrication abnormality detecting means 120 an injection signal 61a (see FIG. 1) indicating the timing of injecting the lubricating oil from the nozzle 20.

In the case of this embodiment, the lubricating oil supply passage 130
As shown in FIG. 2, the multi-branch piping device 9 and the piping 1 are connected to the piping 38 connected to the discharge port of the ultra-trace amount lubricating oil pump 5.
0 is combined to form a branch supply path for guiding lubricating oil to a plurality of nozzles 20. In the case of the present embodiment, a clogging sensor (pressure sensor) 8 for detecting clogging of a pipeline by a pressure increase is provided at a connection portion between the pipe 38 and the multi-branch piping device 9.

The ultra-trace lubricating oil pump 5 has the configuration shown in FIG. Although not described in detail in order to avoid repetition of the description, the micro-trace lubricating oil pump 5 pumps the lubricating oil introduced from the lubricating oil tank 2 (see FIG. 2) into the pump chamber 37 via the lubricating oil conveying pipe 41. The lubricating oil supply passage is discharged to a pipe 38 by a piston 35 slidably reciprocating within a cylinder 36 in a pump chamber 37. The lubricating oil conveying pipe 41 communicates with a suction port 39 of the pump chamber 37. A suction valve (check valve) 40 for preventing backflow from the pump chamber 37 to the lubricating oil conveying pipe 41 side is provided, and the reciprocating operation of the piston 35 is performed by the expansion and contraction operation of the rod 30. The reference numeral 30 uses a giant magnetostrictive element that expands when a magnetic field is applied.

The nozzle 20 of the lubrication device 110 is mounted on the housing 18 for each of the rolling bearings 16 and 17. Each nozzle 20 is equipped with the cylindrical portion 18a of the housing 18 and the sleeve 18b inserted therethrough, and directs the injection port to the rolling element between the inner and outer rings of the rolling bearings 16 and 17.

The lubricating device 110 having the above configuration constitutes a lubricating device of an ultra-trace oil lubrication system disclosed in Japanese Patent Application Laid-Open No. 2000-110711, in which the discharge speed of the lubricating oil from each nozzle 20 is 13 to 0.0008 to 0.01 cc (ml) per shot in the range of 200 m / s
Supply of a very small amount of lubricating oil in the range of

The torque output from the electric motor 23 is transmitted to the main shaft 15 via a belt 29 wound around the belt pulley 23a mounted on the output shaft and the main shaft 15. The shaft drive unit 25 of the present embodiment is a control circuit that supplies power to the electric motor 23 so that the main shaft 15 is driven at a required rotation speed. Is output to the pen recorder 27 and the lubrication abnormality detecting means 120. The pen recorder 27 records the power consumption signal output from the shaft drive unit 25 on a predetermined sheet.

In the above-described spindle device 1, when lubricating oil is injected from the nozzle 20 into the rolling bearings 16 and 17,
Since the frictional resistance of the rolling elements in the rolling bearings 16 and 17 increases due to the injected lubricating oil, the dynamic torque of the rolling bearings 16 and 17 increases. This phenomenon of increase in the dynamic torque has a degree of increase corresponding to the amount of lubricating oil injected into the rolling bearings 16 and 17, and the driving force of the electric motor 23 driving the main shaft 15 causes the rolling bearings 16 and 17 to rotate. A fluctuation corresponding to the degree of increase of the dynamic torque is caused. The lubrication abnormality detecting means 120 according to the present embodiment focuses on such operation characteristics of the main shaft 15, and calculates the power consumption of the electric motor 23 based on the power consumption signal notified from the shaft drive unit 25. When the fluctuation range of the driving force of the electric motor immediately after the shot of the lubricating oil exceeds the standard range, the abnormality of the supply state of the lubricating oil to the rolling bearings 16 and 17 is detected. An error notification is sent to the shaft drive unit 25 to stop the operation.

Further, in the ultra-micro oil lubrication system, since the amount of lubricating oil to be injected is very small, the rise in bearing torque due to the shot of lubricating oil returns to the normal value about 1 second immediately after injection. Subsequent monitoring does not see much useful data. Therefore, in the case of the present embodiment, the monitoring of the power consumption of the electric motor 23 by the lubrication abnormality detecting means 120 is based on the timing of the lubricating oil shot by the nozzle 20 notified from the lubricating device 110 for about 10 seconds before the shot. And the monitoring period is set within about 1 second immediately after the shot, and the fluctuation range of the driving force is calculated by comparing the maximum driving force in the monitoring period before the shot with the maximum driving force in the monitoring period immediately after the shot. Then, when the fluctuation range exceeds the standard range, it is determined that the lubricating oil supply is abnormal.
The lubrication abnormality detecting means 120 determines that the supply amount of the lubricating oil is insufficient when the fluctuation range of the driving force is equal to or smaller than the standard range. In any case, the shaft drive unit 25 is notified of the abnormality, and the rotation drive by the electric motor 23 is stopped. The lubrication abnormality detection means 120 notifies the shaft drive unit 25 of an abnormality when, for example, an abnormality is detected for 2 to 5 consecutive shots, in order to avoid a sudden stoppage due to erroneous detection due to the influence of noise. Is performed.

Next, in the ultra-micro oil lubrication system using the lubrication device 110 of the present embodiment, the discharge speed of the nozzle 20
The operation of the spindle device 1 will be described after supplementary explanation based on the test results conducted by the applicant of the present invention, etc., on the reason why the discharge amount is defined as the above-mentioned optimum range.

FIG. 3 is a graph showing the relationship between the discharge diameter of the nozzle 20 for injecting the lubricating oil and the discharge speed, and shows the results of a test using the discharge diameter of the nozzle 20 as a parameter. As shown in the drawing, the smaller the discharge diameter of the nozzle, the smaller the discharge amount and the higher the discharge speed. At this time, the lubricating oil is discharged at a discharge speed of 13 to 200 m / sec, and the discharge oil amount per discharge is 0.1.
0008 to 0.01 cc (ml). Further, the discharge speed and the discharge oil amount are also affected by the dynamic viscosity characteristics of the lubricating oil,
In the case of a lubricating oil having a kinematic viscosity at 5 ° C. of 5 to 50 cSt, the discharge speed is in the range of 10 to 100 m / sec and the discharge oil amount is 0.000.
It will be in the range of 5 to 0.01 cc (ml).

Next, a rotation test was conducted using the spindle device 1 of the present embodiment, and
And a conventional oil-air lubrication system were compared.

Outer ring diameter is 160 mm, inner ring diameter is 100 m
m, the rolling element pitch circle diameter d _m is 132.5Mm, outer inner ring groove curvature from 52 to 56%, the contact angle is 20 °, the inner and outer rings Material S
UJ2, bearing material of rolling element material is Si ₃ N ₄ , lubricating oil is mineral oil VG22 (kinematic viscosity is 22cSt at 40 ° C, axial load is 980N, and the number of nozzles used is 3 in the case of conventional oil-air lubrication; In the case of the lubricating oil pump 5, one lubricating oil pump 5 is used at 0 to 15,000 rpm (partly at 19,000 rpm).
_Dm · N = 2,500,000). Tests such as the relationship between the shaft rotation speed and the bearing torque, the relationship between the shaft rotation speed and the outer ring temperature rise, and the comparison of the bearing torque fluctuation were performed.

FIG. 4 is a graph showing the relationship between the shaft rotation speed and the bearing torque. In the figure, in the case of the oil-air lubrication system, each of the three nozzles has a nozzle diameter of 0.1 mm.
In the case of the ultra-trace oil lubrication system of this embodiment, 03 cc (ml) of lubricating oil is applied every 8 minutes, and 0.002 cc (ml) of lubricating oil is applied from one nozzle to each shot for 10 seconds. Corresponding to the data in the case of discharging at an interval of 40 seconds and 1 second, the amount of oil discharged per unit time is 0.01125 cc (ml) / min and 0.012 cc (m
l) / min, 0.003cc (ml) / min, 0.012c
c (ml) / min. In the conventional oil-air lubrication method, the rotation speed 15,000rpm (d _m · N = 2,00
0,000), the bearing torque is 0.18 N · m, whereas in the ultra-trace oil lubrication system of the present embodiment, it is as low as 0.14 N · m, and further, 19,000 rpm.
(D _m · N = 2,500,000) but, bearing torque was 0.16 N · m, towards the device of the present invention is a low torque.

According to the torque characteristics shown in FIG. 4, when the supplied oil amount is in the range of 0.003 to 0.12 cc (ml) / min, the torque in the case of the ultra-micro oil lubrication system has a rotation speed of 1 rpm.
At 2,000 to 15,000 rpm, at higher speeds, the torque becomes smaller when the supply interval is shorter, that is, when the amount of supplied oil per unit time is larger. This is because a certain amount of lubricating oil is required to prevent a decrease in the oil film forming ability due to a temperature rise at high speed. That is, there are optimal lubricating oil amounts, lubricating oil supply intervals, and discharge oil amounts depending on the operating rotational speed. It is possible to set the optimal lubricating oil amount, lubricating oil supply interval, and discharge amount at this rotational speed according to the maximum rotational speed.However, if a large amount of lubricating oil is supplied, the bearing torque will increase at low speed rotation. It can be too much. In this case, it is desirable that the control device obtains the lubricating oil amount, the lubricating oil supply interval, the discharge oil amount, and the like for each rotational speed in accordance with the rotational speed, and optimizes the lubricating oil supply.

FIG. 5 is a graph showing the relationship between the shaft rotation speed and the outer ring temperature rise. As can be seen from this graph, the ultra-trace amount oil lubrication system is lower in temperature than the conventional oil-air lubrication system even with the outer ring temperature rise. 4 and 5 show the case of the oil-air lubrication system.
Although only data up to a rotation speed of 15,000 rpm is shown, this is because the rotation speed is 15,000 rpm to 1
This is because the temperature rise gradient was steep during the speed increase to 7,000 rpm, and the test was interrupted because the outer ring temperature rise exceeded 60 ° C. That is, compared with the oil-air lubrication system, the ultra-trace oil lubrication system has a smaller torque, can suppress the temperature rise, and can perform high-speed rotation.

In the case where an excessive supply of the lubricating oil causes an increase in the torque on the shaft side or an increase in the bearing temperature during low-speed rotation, as a countermeasure against this, in the ultra-small lubricating oil pump 5, for example, the application to the coil 43 is performed. By reducing the current, the intensity of the magnetic field applied to the rod 30 by the coil 43 is reduced, and the elongation of the rod 30 is reduced, so that the lubricating oil supply amount can be reduced to an appropriate value. Optimization control of the supply amount is easily possible.

To summarize the above, by using the ultra-micro oil lubrication method and setting the discharge speed of the lubricating oil from the nozzle and the discharge amount per shot as described above to the appropriate range, Auxiliary equipment such as oil mist lubrication system, oil air lubrication system, jet lubrication system, lubricating oil forced lubrication system, heat exchanger, lubricating oil recovery system, compressed air, etc. can be simplified and noise level can be kept low. And also consumes less lubricating oil, so it can be considered for the environment, and has low bearing torque and excellent stability.
Since the bearing temperature rise is low, the rotation accuracy of the main shaft can be improved. Therefore, it is possible to provide a small-sized spindle device 1 which is superior to the spindle device 1 using the conventional lubrication method.

In the present embodiment, the giant magnetostrictive element is used as a drive source for reciprocating the piston 35 for discharging the lubricating oil in the micro-lubricating oil pump 5.
The drive source of No. 5 is not limited to the giant magnetostrictive element, and it is possible to use a technique such as an electrostrictive element, a combination of an electromagnet and a disc spring, or another mechanical mechanism. At a discharge speed of 13 to 200 m / sec, 0.0008 to
If a small amount of oil discharge of 0.01 cc (ml) / shot is realized, the same good rotation performance as the spindle device 1 can be obtained. Similar effects can be obtained with a giant magnetostrictive element used for driving the piston 35 in addition to a giant magnetostrictive material having a positive characteristic and a magnetostrictive material having a bidirectional characteristic.

Next, based on FIG. 1 and FIG.
Will be described in detail. The lubricating oil 25 filled in the lubricating oil tank 2 is supplied to the lubricating oil filter 3 and the air release device 4.
And flows into the ultra-trace lubricating oil pump 5. The control device 61 controls the intermittent time for lubricating oil supply, adjusts the amount of lubricating oil, controls the multi-branch piping mechanism, etc., and lubricates each pipe 10 with the multi-branch piping device 9. Oil 2
Send 5 The lubricating oil 25 sent to each pipe 10 is reliably injected and supplied into each of the rolling bearings 16 and 17 by the nozzle 20. In this case, the angle and the position of each nozzle 20 are adjusted to an optimal state, and an appropriate amount of lubricating oil 25 is supplied into each of the rolling bearings 16 and 17. The intermittent time adjustment and the lubricating oil amount adjustment by the control device 61 are performed based on the output of a tachometer (not shown) that detects the rotation speed of the main shaft. The adjustment of the amount of lubricating oil can also be performed using a very small amount of flow sensor.

When supplying the lubricating oil, the lubricating oil filter 3 removes dust and the like that cause clogging at the outlet of the lubricating oil tank 2. However, when dust or the like mixed in the lubricating oil for some reason passes through the lubricating oil filter 3 and causes clogging of the flow path in the ultra-trace lubricating oil pump 5 or in front of the multi-branch piping device 9, If the pressure change in the pipeline due to the clogging exceeds a reference value, the clogging sensor 8 detects the occurrence of clogging, so that oversight of clogging in the vicinity of the ultra-micro amount lubricating oil pump 5 is avoided. Can be. Further, when air is mixed, the mixed air is removed by the air bleeding device 4 made of a porous material, and there is no possibility that the mixed air causes a pressure fluctuation in the pipe line that mistakenly identifies an abnormal supply of the lubricating oil.

Further, in the spindle device 1 of the present embodiment, the lubricating oil supply amount is reduced for some reason such as failure of the ultra-small amount lubricating oil pump 5 constituting the lubricating device 110 or clogging of the nozzle 20. Then, eventually, the phenomenon of the increase in power consumption of the electric motor 23 immediately after the shot is reduced, so that the lubrication abnormality detecting means 120 can quickly and reliably detect the shortage of the lubricating oil supply amount. Therefore, it is possible to reliably prevent an accident such as seizure of a bearing caused by oversight of an abnormality such as insufficient supply of lubricating oil. In addition, the number of existing parts that need to be modified in order to detect the shortage of the lubricating oil supply amount is smaller than that in the case where the lubrication abnormality detecting means is incorporated in the ultra-small amount lubricating oil pump 5 itself. It can be cheap. Accordingly, it is possible to improve the rotational performance of the spindle device 1 and the life of the bearing unit by improving the reliability of the lubrication performance, and at the same time, it is possible to reduce the manufacturing cost.

6 to 9 are power consumption diagrams of the electric motor 23 recorded by the pen recorder 27. FIG. In each figure, the vertical axis indicates the power consumption of the motor, and the horizontal axis indicates the elapsed time. FIG. 6 shows an interval of 120 seconds / shot,
The discharge amount of lubricating oil per shot is 0.0015cc (m
In 1), lubricating oil is supplied, and the number of revolutions of
The power consumption at 00 rpm is recorded. Projection y ₁ to exposed at a substantially constant intervals on consumption power lines f ₁ to take an approximately constant value, is an increase of power consumption due to the increase of the bearing torque immediately after the shot. On consumption power lines f _2, since the increase in power consumption of approximately the same size are obtained stably, it can be seen that satisfactorily stable lubricating oil supply is made.

FIG. 7 shows that lubricating oil is supplied at an interval of 60 seconds / shot at a lubricating oil discharge rate of 0.0015 cc (ml) per shot, and the number of revolutions of the main shaft 15 is 25,000 rpm.
The power consumption at pm is recorded. Projections y ₂ appearing at substantially constant intervals on the power consumption line f ₂ having substantially constant values
Is an increase in power consumption due to an increase in bearing torque immediately after the shot. On consumption power lines f _2, since the increase in power consumption of approximately the same size are obtained stably, it can be seen that satisfactorily stable lubricating oil supply is made.

FIG. 8 shows that lubricating oil is supplied at an interval of 60 seconds / shot at a lubricating oil discharge amount of 0.0015 cc (ml) for each shot, and the number of revolutions of the main shaft 15 is 25,000 rpm.
The power consumption at pm is recorded. And intentionally stopping the supply of the lubricating oil at the time of the middle operating time T _1, and record changes in subsequent power consumption. In the time T ₁ before,
Projection y ₂ be exposed at substantially constant intervals on consumption power lines f ₂ that takes an approximately constant value, is an increase of power consumption due to the increase of the bearing torque immediately after the shot. On consumption power lines f _2, since the increase in power consumption of approximately the same size are obtained stably, it can be seen that satisfactorily stable lubricating oil supply is made. However, the time T ₁ hereinafter, not only the projection y ₂ can not be seen exhibiting elevated power consumption, in a short time, is caused excessive increase y ₃ which power consumption increases rapidly,
It was confirmed that seizure of the bearing occurred.

FIG. 9 shows that lubricating oil is supplied at an interval of 60 seconds / shot at a lubricating oil discharge rate of 0.0015 cc (ml) per shot, and the rotational speed of the main shaft 15 is 24,000 r.
The power consumption at pm is recorded. And causing clogging in the nozzle 20 at the time of the middle operating time T _2,
The subsequent changes in power consumption were recorded. The time T ₂ previously, substantially constant value projection y ₄ that exposed at a substantially constant intervals on the consumption power lines f ₄ taking is, the time T ₂ later, variation of frequent power consumption at small intervals from the shot interval occurs It became clear that stable lubricating oil supply was not achieved.

In this embodiment, the driving force of the electric motor monitored by the lubrication abnormality detecting means is the electric motor 2
Although the power consumption of No. 3 is selected, a load torque or a drive current acting on the electric motor 23 can be selected instead of the power consumption, and the power consumption, the load torque, or the drive power is used as the driving force of the electric motor. Which of the electric currents should be used should be selected in consideration of the existing equipment and environment, for example, one that reduces the burden on equipment costs and the like. By selecting the driving force of the electric motor monitored by the lubrication abnormality detecting means in this way, the degree of freedom in designing the lubrication abnormality detecting means is improved, and the design is facilitated.

In general, in the ultra-trace oil lubrication system, the lubricating oil is intermittently supplied by setting the shot interval to an appropriate value, for example, 60 seconds / shot or 120 seconds / shot. By setting the monitoring time zone to about 10 seconds before the shot and about 1 second immediately after the shot,
Accumulation of unnecessary data is minimized, only useful data is monitored efficiently, and the amount of data recorded can be reduced. Can be reduced.

(Second Embodiment) FIG. 10 shows a spindle device 140 according to a second embodiment of the present invention. The spindle device 140 shown here is used as a spindle device of a machine tool, and has a configuration in which the spindle device 1 of the first embodiment is further equipped with a conduction detecting means 160.
Structures other than the conduction detecting means 160 are the same as those of the first embodiment, and the common structures are denoted by the same reference numerals and description thereof will be omitted.

The conduction detecting means 160 provided in the spindle device 140 is a brush 1 which is electrically connected to the spindle 15.
A power supply 163 and a resistor 164 are connected in series in the middle of a conductive path 162 for electrically connecting the workpiece 61 to the workpiece 150, and the workpiece 150 to which the main shaft 15 contacts is electrically conductive. In the case of having, the state in which the main shaft 15 and the work 150 are in contact with each other is detected by detecting an electrical short-circuit state between the two, and the conduction signal 166 is notified to the lubrication abnormality detection means 120, The monitoring by the lubrication abnormality detecting means 120 is limited to a time when the spindle 15 and the work 150 are in a non-short circuit state. Generally, in a machine tool, the time during which the spindle is rotationally driven in a non-cutting state (that is, a state in which the spindle and the workpiece are not in contact with each other) often occupies several tens% or more. By operating the lubrication abnormality detecting means in the belt, the reliability of detecting the lubricating oil supply abnormality can be improved.

The type of the rolling bearing used in the spindle device of the present invention, the mounting position of the rolling bearing, the number of the rolling bearing, and the like are not limited to the above-described embodiment, and the gist of the present invention. It is needless to say that the design can be changed as appropriate without departing from the range.

In the present embodiment, the electric motor 23
Is not limited to the belt-type power transmission mechanism described in the above embodiment, and may be, for example, a type that is directly connected by a coupling with a built-in reduction gear, or a type that is electrically driven. It is also possible to adopt a motor built-in type structure in which a motor is built in the main shaft 15 itself.

[0053]

According to the spindle device of the present invention, when lubricating oil is injected from the nozzle into the inside of the rolling bearing, the injected lubricating oil increases the frictional resistance of the rolling elements in the rolling bearing. Dynamic torque increases. This phenomenon of increase in dynamic torque has a degree of increase corresponding to the amount of lubricating oil injected into the rolling bearing, and also depends on the degree of increase in dynamic torque of the rolling bearing in accordance with the driving force of the electric motor driving the main shaft. Brings fluctuation. Therefore, if the supply amount of the lubricating oil is reduced for any reason such as failure of the ultra-trace lubricating oil pump constituting the lubricating device or clogging of the nozzle, the driving of the electric motor driving the main shaft is eventually completed. According to the above-described configuration in which the fluctuation state of the driving force of the electric motor is monitored by the lubrication abnormality detecting means in order to be embodied as a phenomenon in which the fluctuation amount of the force is reduced, even if the lubricating oil supply is reduced for any reason, the lubricating oil supply can be performed quickly and Insufficient supply of lubricating oil can be reliably detected, and accidents such as seizure of the bearing caused by oversight of an abnormality such as insufficient supply of lubricating oil can be reliably prevented. In addition, the number of existing parts that need to be modified in order to detect a shortage of lubricating oil supply is smaller than when, for example, incorporating a lubrication abnormality detecting means into the ultra-micro lubricating oil pump itself.
The improvement cost can be reduced. Therefore, the improvement of the reliability of the lubrication performance can improve the rotation performance of the spindle device and the life of the bearing portion, and can reduce the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a spindle device according to the present invention.

FIG. 2 is a block diagram showing a configuration of a lubrication device in the spindle device of FIG.

3 is a graph showing a relationship between a nozzle shape and a discharge speed of lubricating oil in a lubrication device of an ultra-micro oil lubrication system used in the spindle device of FIG.

FIG. 4 is a graph showing a relationship between a shaft rotation speed and a bearing torque in the spindle device of FIG.

5 is a graph showing a relationship between a shaft rotation speed and an outer ring temperature rise in the spindle device of FIG. 1;

FIG. 6 is a perspective view of the shaft receiving device shown in FIG.
FIG. 9 is a measurement diagram of a motor driving force when driven to rotate at 000 rpm.

FIG. 7 is a perspective view of the shaft receiving device shown in FIG.
FIG. 9 is a measurement diagram of a motor driving force when driven to rotate at 000 rpm.

FIG. 8 is a sectional view of the shaft receiving device shown in FIG.
FIG. 9 is a diagram illustrating a measurement of a motor driving force when the supply of lubricating oil is stopped during rotation driving at 000 rpm.

FIG. 9 is a perspective view of the shaft receiving device shown in FIG.
FIG. 9 is a diagram illustrating a measurement of a motor driving force when clogging of a nozzle occurs during rotation driving at 000 rpm.

FIG. 10 is a block diagram showing a configuration of a spindle device according to a second embodiment of the present invention.

FIG. 11 is a schematic explanatory diagram of a conventional lubricating device of an ultra-trace oil lubrication system using an ultra-trace oil lubricant pump.

[Explanation of symbols]

 Reference Signs List 1,140 Spindle device 5 Ultra-micro lubricating oil pump 15 Spindle 16, 17 Rolling bearing 18 Housing 20 Nozzle 23 Electric motor 25 Shaft drive unit 27 Pen recorder 110 Lubricating device 120 Lubrication abnormality detecting means 130 Lubricating oil supply path

Claims (1)

[Claims] 1. A main shaft, a housing through which the main shaft is inserted, and a rolling bearing rotatably supporting the main shaft on the housing at a plurality of positions spaced apart in an axial direction of the main shaft,
A shaft drive unit that drives the main shaft to rotate at a high speed by an electric motor; and a lubrication device that supplies lubricating oil to the rolling bearing, and the lubricating device directs the lubricating oil to a predetermined portion of the rolling bearing. A nozzle for injecting the lubricating oil, a lubricating oil pump that intermittently discharges the lubricating oil with a very small discharge amount, and a lubricating oil supply path that guides the lubricating oil sent by the lubricating oil pump to the nozzle, In a spindle device for intermittently injecting a small amount of lubricating oil from the nozzle to the rolling bearing, a driving force of the electric motor is monitored, and a fluctuation range of the driving force of the electric motor immediately after the lubricating oil is shot is within a standard range. A spindle device provided with lubrication abnormality detection means for detecting an abnormality in the state of supply of the lubricating oil to the rolling bearing when it deviates.