JP2000110711A - Lubricating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small lubricating device for implementing a high-speed rotation shaft, which can quickly inject an accurately set, fixed, very small quantity of lubricating oil directly onto a lubrication surface of a rotator, facilitates adjustment of the injection quantity, and causes a small temperature rise. SOLUTION: A piston 7 is fixed to the other end 1b of a rod 1 made of a magnetostrictive material and having its one end 1a fixed. This piston 7 is slidably provided within a cylinder 9 forming a pump chamber 11. An inlet port 15 for introducing lubricating oil into the pump chamber 11 is provided in the cylinder 9, and an inlet valve 17 for preventing the lubricating oil from flowing out from the inlet port 15 is provided at the inlet port 15. A nozzle 13 communicating with the pump chamber 11 and having a cross-sectional area smaller than that of a lubricating-oil passage of the inlet valve 17 is provided at the cylinder 9. A coil 23 is provided outside the rod 1, and a controller (driving circuit) 27 for controlling a supply current is connected to the coil 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a trace amount of (0.00
The present invention relates to a lubricating device which is required to adhere a lubricant (approximately 01 to 0.003 cc) to a lubricating surface in an accurate amount.

[0002]

2. Description of the Related Art Conventional lubricating devices for supplying a lubricant to a high-speed rotating body include an oil-air lubricating device, an oil mist lubricating device, and a forced lubricating device. The oil-air lubricating device is composed of a tank, a pump, a distributor, a compressed air source, a plunger, and a nozzle, and a lubricant droplet (0.01 to 0.03 cc) adjusted to a fixed amount by a mechanical mechanism of the plunger.
Is discharged into an air pipe, carried to a nozzle by air, and jetted to a lubricating surface. Oil mist lubrication system
It is composed of a plunger, distributor, compressed air source, electromagnetic valve, and nozzle. The lubricant is made into fine mist, conveyed through the air pipe by compressed air, and sprayed on the lubricated surface. In a forced lubrication (jet lubrication) device, oil is made high in pressure by a pump and a nozzle diameter is reduced to increase a jetting speed in order to penetrate an ultrahigh-speed air wall on a lubrication surface.

[0003] However, the above oil-air lubrication system is
Since it is difficult to continuously and stably supply a small amount of lubricant, it has to be intermittently lubricated, and the bearing temperature rises immediately after lubrication. Further, the oil mist lubricating device has a disadvantage that the amount of the lubricant adhering to the lubricating surface is uncertain because the mist is scattered into the atmosphere, and the working environment is deteriorated. In these lubricating devices, since the lubricant is carried through the pipe by high-pressure air, the amount of oil adhering to the lubricating surface is unstable, and there is also a problem in terms of noise.
Further, the jet lubrication device requires a high-pressure pump, and also requires an oil drainage mechanism to prevent an increase in stirring resistance due to a large amount of oil.

[0004] As a solution to the difficulty of such a minute adjustment of the lubricant, there is one disclosed in the following gazettes. The device for finely dispensing liquid disclosed in Japanese Patent Publication No. Hei 21-15003 enables fine adjustment using an electrostrictive element, and conveys a lubricant to a nozzle by compressed air. Tokuhei 7-65
In the fluid control valve disclosed in Japanese Patent No. 695, a diaphragm is provided at one end of a magnetostrictive element, and an orifice is adjusted by expansion and contraction of the magnetostrictive element to adjust a flow rate and a pressure. JP Hei 3
In the giant magnetostrictive pump disclosed in JP-A-222877, the displacement of the giant magnetostrictive material family is enlarged by a lever, and the diaphragm is driven by the lever to make the pressure in the pump chamber negative and positive, thereby sucking and discharging the fluid. Let it. US Patent 4,795,3
Japanese Patent Publication No. 18,4,804,314 discloses a magnetic precision pump (Magnetostrictive Pump) in which a piston made of a magnetostrictive material is provided in a cylinder, and a voltage is applied to a coil provided around the piston. The piston is expanded and contracted to discharge the fluid in the cylinder. JP-A-4-8
The giant magnetostrictive fuel injection pump disclosed in Japanese Patent No. 1565 opens and closes a needle valve with a giant magnetostrictive material, and injects a fixed amount of high-pressure liquid.

[0005]

However, the pump or fluid control valve using the above-described giant magnetostrictive material has the following problems. Tokuhei 215003
The fine metering device disclosed in Japanese Patent Application Laid-Open Publication No. 2000-214,199 does not solve the drawback caused by transporting the lubricant to the nozzle by high-pressure air. In the fluid control valve disclosed in Japanese Patent Publication No. 7-65695, the diaphragm area to which the liquid pressure is applied becomes larger than the cross-sectional area of the giant magnetostrictive material, and the pressure of the liquid becomes smaller than the pressure of the giant magnetostrictive material. In the giant magnetostrictive pump disclosed in Japanese Unexamined Patent Publication No. Hei 3-222877, the displacement is expanded by the lever, so that the liquid pressure becomes smaller than the pressure of the giant magnetostrictive material. The output of the giant magnetostrictive material increases with an increase in the magnetic field generated by the coil, but the required volume of the coil also increases with an increase in the coil magnetic field. As a result, a new problem arises in that the size of the device using the same increases. U.S. Pat. Nos. 4,795,318, 4,804,314
In the magnetic precision pump disclosed in Japanese Patent Laid-Open Publication No. H11-107, the pressure of the lubricant cannot be higher than the pressure of the giant magnetostrictive material because the piston itself is composed of the drive element. The giant magnetostrictive fuel injection pump disclosed in JP-A-4-81565 does not have a function of increasing the pressure of a liquid.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and it is possible to spray a fixed amount of lubricant set at high precision at a high speed and directly adhere to a lubricating surface of a rotating body, and to adjust a spray amount. And to provide a small lubricating device for realizing a high-speed rotating shaft with small temperature rise.

[0007]

According to a first aspect of the present invention, there is provided a lubricating apparatus for expanding and contracting a rod made of a magnetostrictive material by applying and removing a magnetic field to the rod. A lubricating device that discharges pressurized lubricant using a magnetostrictive pump having a pump chamber that pressurizes the lubricant by the expansion and contraction operation is provided in the middle of a flow path that supplies the lubricant to the magnetostrictive pump. A check valve for preventing the lubricant from flowing out of the magnetostrictive pump, and a check valve disposed on the lubricant discharge side of the magnetostrictive pump, and having a flow passage cross-sectional area smaller than a lubricant flow passage cross-sectional area of the check valve. And a nozzle having the same.

[0008] In this lubricating device, the rod is elongated by applying a magnetic field, and the lubricant in the pump is compressed. This allows
The pressure in the flow path for supplying the lubricant is increased, the check valve is closed, and the lubricant is injected from the nozzle to the outside at a high speed. When the application of the magnetic field is turned off, the rod body contracts, the internal volume in the pump increases, and the lubricant is refilled into the pump through the check valve. At this time, air also flows in from the tip of the nozzle, but since the ratio of the flow rate of the lubricant to the air is proportional to the square of the flow path cross-sectional area ratio of the check valve and the nozzle, the flow rate of the lubricant is larger than that of the air. As a result, the same lubricant can be discharged during the next operation.

A lubricating apparatus according to a second aspect of the present invention is characterized in that one end of the rod is fixed, a piston is connected to the other end, and the piston is slidably provided in the cylinder. Wherein the cross-sectional area of the inner surface of the cylinder is smaller than the cross-sectional area of the rod.

In this lubricating device, the piston in the cylinder moves due to the expansion and contraction of the rod, thereby forming a pump. Then, the pressure of the lubricant in the cylinder becomes higher than the pressure generated by the rod, so that the lubricant can be discharged at a high speed.

According to a third aspect of the present invention, in the lubricating apparatus, the reduced volume of the pump chamber due to the extension of the rod is reduced by the amount of air flowing from the nozzle when the rod is contracted, the check valve, and the nozzle outlet. A volume decrease due to compression of the lubricant in the internal volume, a volume increase of the internal volume due to pressure deformation of components constituting the internal volume, and a required discharge amount of the lubricant. I do.

In this lubricating device, the control of the magnetic field applied to the rod is related to the amount of air flowing from the nozzle, the reduction in volume due to the compression of the lubricant, and the increase in the internal volume due to the pressure deformation of the components constituting the internal volume. Since the correction is performed with a value that takes into account the variable elements, the ejection amount error due to these variable elements is eliminated, and a desired discharge amount can be obtained with high accuracy.

According to a fourth aspect of the present invention, in the lubricating apparatus, the magnetostrictive pump includes a coil for applying a magnetic field, and a control device for controlling expansion and contraction of the rod by controlling a current supplied to the coil. Supplies an electric current until the pressure of the lubricant in the pump chamber at which a desired discharge speed is obtained by the magnetostrictive pump at the time of initial excitation of the coil, and after reaching the pressure, responds to the discharge amount of the lubricant. And supplying a current for keeping the pressure of the lubricant constant, and turning off the supply current after a desired lubricant discharge amount is obtained.

In this lubricating device, when an electric current is passed from the control device to the coil, the rod body extends, and the piston compresses the lubricant in the pump chamber. Thereby, the pressure in the cylinder is increased, the suction valve is closed, and the lubricant is injected from the nozzle to the outside at a high speed. At this time, for example, at the time of initial excitation of the coil, the control device supplies a current until a desired discharge speed is obtained by the magnetostrictive pump, and quickly starts up to the current value. During this time, a high voltage is applied to the coil, and the current rises quickly against the time constant of the coil. Then, after reaching a current value at which a desired discharge speed is obtained, in order to maintain a constant lubricant pressure which decreases in accordance with the discharge amount of the lubricant, the current is reduced so that the cylinder volume is reduced by a volume equal to the discharge amount. Supply. During this time, the voltage is switched to a voltage at which a desired current rising speed is obtained by the time constant of the coil. Next, after a desired lubricant discharge amount is obtained, the supply current to the coil is turned off. As a result, a required lubricant pressure can be obtained from the beginning of the discharge of the lubricant, a constant discharge speed can be maintained after the start of the discharge of the lubricant, and accurate and stable discharge of the lubricant can be performed. When the current is turned off, the rod contracts, the internal volume of the pump chamber increases, and the lubricant is supplied to the pump chamber through the suction valve.

According to a fifth aspect of the present invention, there is provided a lubricating device, wherein: the rotational speed detecting means for detecting a rotational speed of the rotating body to which the lubricant is supplied; and the coil according to the rotational speed detected by the rotational speed detecting means. And a lubricant discharge amount adjusting means for setting a current value of a supply current to the fuel cell and an operation frequency.

In this lubricating device, when supplying the lubricant to the rotating body, it is possible to supply the optimum amount of the lubricant to the rotating body which changes according to the number of rotations, so that excessive supply or insufficient supply of the lubricant is prevented. Is prevented.

According to a sixth aspect of the present invention, there is provided the lubricating apparatus, wherein the measuring means measures one of a current value supplied to the coil, a voltage value proportional to the current, and a magnetic flux value generated by the current. Abnormality determination means for determining whether an abnormality has occurred by comparing the measured value for the elapsed time with the measured value in normal times, and when the abnormality determination means determines that an abnormality has occurred, an abnormality signal is generated. Characterized in that it occurs.

In this lubricating device, for example, when the object to be measured is a current value, the current value measured when a certain time has elapsed from the start of the current supply is larger than the normal current value (design value), that is, If the time required to increase to a certain current value is shorter than the design value, it can be determined that an abnormality such as nozzle clogging has occurred. Conversely, if the current value measured at a certain time after the start of the current supply is smaller than the design value, that is, if the time required to increase to a certain current value is longer than the design value, lubricant leakage etc. Can be determined to have occurred. Further, the abnormality can be determined in the same manner by using the voltage value and the magnetic flux value as the measurement target. By generating an abnormal signal when an abnormality occurs, feedback control such as stopping the operation of the lubricant supply target can be performed.

According to a seventh aspect of the present invention, there is provided the lubricating device, wherein the measuring means measures one of a current value supplied to the coil, a voltage value proportional to the current, and a magnetic flux value generated by the current. An air entrapment determining means for judging the presence or absence of air entrapment by comparing the measured value for the elapsed time with the measured value at the time of no air entrapment,
The current supplied to the coil is increased or the current supply frequency is increased until the air mixing determining means determines that there is no air mixing at the start of the operation of the lubricating device.

In this lubricating apparatus, for example, when the object to be measured is a current, if air is mixed into the lubricant, the rise time of the measured current becomes longer, so that the presence or absence of air mixing can be determined. Further, the abnormality can be determined in the same manner by using the voltage value and the magnetic flux value as the measurement target. At the start of the operation of the lubricating device, the current supplied to the coil is increased, or the supply frequency of the current is increased, or both are performed until it is determined that there is no air mixing. The discharge cycle can be increased, the lubricant can be quickly sucked into the pump from the tank, and the air bleeding can be completed in a short time.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a lubricating device according to the present invention will be described below in detail with reference to the drawings. FIG.
1 is a sectional view of a lubrication device according to the present invention. According to FIG. 1, one end 1 a in the axial direction of a rod 1 made of a positive magnetostrictive material is fixed to a case 5 via a preload adjusting mechanism 3. The giant magnetostrictive material of the rod 1 is, for example, Edge
Technologies (trade name: Terfenol-D, manufactured by Technologies (ETREMA Division)) and magnetostrictive materials, manufactured by TDK, can be suitably used. When a magnetic field is applied by a later-described coil provided coaxially, the rod 1 extends in the axial direction due to a magnetostriction phenomenon (Joule effect).

The preload adjusting mechanism 3 can be, for example, a screw mechanism which protrudes in the axial direction of the rod 1 by rotation, and which can press one end 1a of the rod 1. Pressure is transmitted to the other end 1b in the axial direction of the rod 1 by urging the rod 1 toward the preload adjusting mechanism 3 by a disc spring 2a without generating a gap (play) in the axial direction of the rod 1. The piston 7 is fixed via the pressure transmitting member 2. The piston 7 is slidably provided inside the cylinder 9. Cylinder 9
Is the cross-sectional area S of the piston sliding space in the direction orthogonal to the axis,
The rod body 1 is formed to be smaller than the cross-sectional area A in the direction orthogonal to the axis, and a pump chamber 11 is formed therein.
A nozzle 13 is attached to the cylinder 9 via a pipe, and a discharge opening 13 a of the nozzle 13 communicates with the pump chamber 11. Here, no check valve is provided between the pump chamber 11 and the nozzle 13.

The cylinder 9 is provided with a suction port 15 for sucking lubricant into the pump chamber 11. A suction valve 17 is provided at the suction port 15, and the suction valve 17 is a check valve that prevents the lubricant from flowing out of the pump chamber 11. The flow passage cross-sectional area of the suction valve 17 is formed larger than the cross-sectional area of the discharge opening 13 a of the nozzle 13, and the suction port 15 is connected to a lubricant tank 21 via a lubricant transport pipe 19. ing. Therefore,
The lubricant is supplied from the tank 21 to the pump chamber 11 via the lubricant transfer pipe 19, and the lubricant is supplied from the pump chamber 11 to the tank 2.
The structure does not flow backward to 1. The tank 21
Is not limited to the illustrated shape, and may be any other shape.

A coil 23 is provided coaxially on the outer periphery of the rod 1. Further, on the outer periphery of the coil 23, a rod 1
A yoke 25 made of a magnetic material for forming a magnetic circuit is provided. The yoke 25, the base end of the cylinder 9 on the side of the rod 1, and a part of the lubricant conveying pipe 19 are accommodated inside the case 5.

The coil 23 has a control device (drive circuit) 2
7 are electrically connected. Control device 27 outputs a current for generating a magnetic field to coil 23. When this current is applied to the coil 23, a magnetic field is generated from the coil 23, and the rod 1 is extended to discharge the lubricant in the pump chamber 11 from the nozzle 13. The shape of the nozzle 13 is
As shown in FIG. 1, a substantially straight tubular flow path whose diameter is reduced stepwise along the axis of the cylinder 9 is formed. For example, the discharge opening 22 at the front end of the flow path shown in FIG. May be formed. In this case, the lubricating device 100
The lubricant can be supplied to the target position without lowering the degree of freedom of installation. The nozzle 13 is easily detachable, and an appropriate type of nozzle is mounted according to an application target of the lubricating device 100.

Next, the lubricating device 10 constructed as described above will be described.
The operation of 0 will be described. FIG. 3 is a time chart showing a temporal relationship between the current applied to the coil and the lubricant discharge, and FIG. 4 is a block diagram showing a discharge amount correction procedure calculated by the control device to obtain a constant discharge amount. Was. When a current is output from the control device 27 to the coil 23 in the pattern (31) shown in FIG. 3A, the coil 23 generates a magnetic field, and the rod 1 made of a giant magnetostrictive material is elongated. Since the rod 1 has one end 1a fixed, the rod 1 extends in the axial direction on the other end 1b,
Following the extension operation, the piston 7 moves in a pattern (32) similar to the current shown in FIG. When the piston 7 moves, the lubricant in the pump chamber 11 is compressed, and the pressure in the cylinder 9 increases as shown in FIG.
3). As a result, the suction valve 17 of the suction port 15 is closed, and after the air accumulated at the previous discharge at the tip of the nozzle 13 is discharged from the nozzle 13 (34), the lubricant is injected from the nozzle 13 to the outside at a high speed. (35). When the current to the coil becomes steady, the extension of the rod 1 stops, and the pressure in the pump chamber 11 decreases due to the discharge of the lubricant.

Thereafter, when the current output from the control device 27 to the coil 23 is stopped, the elongated rod 1 contracts to return to the original state, and the internal volume of the pump chamber 11 increases. At this time, the pressure in the pump chamber 11 becomes negative as shown in FIG. 3 (c) (36), whereby the lubricant is refilled into the pump chamber 11 through the suction valve 17 as shown in FIG. 3 (e) ( 3
7). At this time, as shown in FIG. 3D, a small amount of air simultaneously flows in from the nozzle tip (38). This inflow of air is sufficiently small as compared with the replenishment amount of the lubricant. This means that the inflow of lubricant and the inflow of air are
The cross-sectional area of the nozzle 13 in the direction perpendicular to the flow path axis is the suction valve 1
7 is sufficiently smaller than the cross-sectional area of the suction valve 17 in the direction orthogonal to the flow axis, and the suction valve 17 is closer to the piston 7 than the nozzle 13, so that the transmission time of the negative pressure is shortened.
The lubricant inflow from 7 is greater than the air inflow.
Therefore, the lubricant can be discharged in the same manner at the time of the next discharge operation. Preferably, the volume of the nozzle hole of the nozzle 13 is desirably a volume abnormality of the air flowing from the nozzle hole in the suction step. This is because the resistance when air passes through the nozzle hole is smaller than the resistance when lubricant passes, so if all of the inside of the nozzle hole becomes air, the fluid resistance of the nozzle hole is higher than that of the suction check valve. Is reduced, and the lubricant may not be easily sucked from the suction-side check valve. Further, a check valve may be provided between the pump chamber and the pipe on the discharge side. In this case as well, it is considered that some air flows in from the nozzle hole due to the response delay of the discharge-side check valve and the closing operation of the valve, and it is possible to avoid liquid dripping of the lubricant from the nozzle tip. The prevention effect is reduced.

Now, the amount of air inflow from the nozzle 13 during the compression of the rod, the amount of volume reduction due to the compression of the lubricant in the inner volume between the suction valve 17 and the nozzle outlet, and the inner volume of the cylinder, piping, etc. Since the internal volume increase due to the pressure deformation of the components constituting the nozzle is present in a small amount, in order to accurately discharge the desired amount of the lubricant from the nozzle 13, the discharge in consideration of these variable factors is required. You need to set the amount.

For this reason, the lubricating device of this embodiment is characterized in that the current from the control device 27 is applied to the coil 23 in consideration of these variable factors. That is, in the present embodiment, as shown in FIG.
The current is set in consideration of “the amount of decrease in the volume of the lubricant during compression”, “increase in the internal volume”, and “the amount of air suctioned when the rod is contracted” as main variable factors. As the variable element, other elements such as the temperature and the viscous resistance of the lubricant may be added.

The volume reduction of the pump chamber 11 due to the extension of the rod 1 is, as shown in equation (1), the amount of air flowing from the nozzle 13 during compression of the rod and the content between the suction valve 17 and the nozzle outlet. It is equal to the sum of the volume reduction due to the compression of the lubricant in the product, the volume increase of the internal volume due to the pressure deformation of the components constituting the internal volume, and the required discharge amount of the lubricant discharged from the nozzle 13.

Volume reduction of pump chamber 11 (cross-sectional area of piston × movement length of piston) = (amount of air flowing from nozzle when rod is contracted) + (volume reduction of lubricant due to high pressure) + (internal volume due to high pressure) Volume increase) + (required discharge amount Qrf) (1)

By controlling the current applied to the coil 23 so as to satisfy the expression (1), 0.0001 to 0.0
It becomes possible to intermittently eject a very small amount of lubricant of about 03 cc at a high speed of about 50 m / s to about the speed of sound. The value of each item of the formula (1) can be measured and set according to the lubricating device to be used.

The discharge amount of the lubricant can be obtained by the equation (2). Qr = Δ · f (2) Here, Qr [cc / sec] is a required discharge amount (set discharge amount).
Where Δ [cc / shot] is the discharge rate in one operation when the rated current is supplied, and f [shot / sec] is the operating frequency (supply frequency) applied to the coil.

The calculated set discharge amount Qr is controlled by being classified into three conditions shown in FIG. 5 according to the value. First, when the set discharge amount Qr is equal to or smaller than the discharge amount obtained by performing the minimum shot at the highest operation frequency, that is, Qr ≦ Δmin ·
In the case of fmax (51), the discharge amount Δ and the operating frequency f in one operation are set to Δ = Δmin and f = Qr / Δmin.

Here, Δmin [cc / shot] is the minimum discharge amount per operation with the minimum controllable current, and is set to 0.0001 [cc / shot] in the present embodiment. Fmax [shot / sec] is the maximum operating frequency that can be output by this device. Therefore, the final set discharge amount Qrf in this case is set by the equation (3). Qrf = Δmin × (Qr / Δmin) (3)

The set discharge amount Qr is Δmin · fmax
<Qr ≦ Δmax · fmax (52) (where,
Δmax [CC / shot] is the maximum discharge amount in one operation by the controllable maximum current), and sets the discharge amount Δ in the position operation and the operating frequency f as follows. Δ = Qr / f
max, f = fmax Accordingly, the final set discharge amount Qrf in this case is set by the equation (4). Qrf = (Qr / fmax) × fmax (4)

Then, the set discharge amount Qr is Δmax · fmax
In the case of <Qr (53), since the discharge capacity of the apparatus is exceeded, the control unit 27 causes the discharge disable signal (FIG. 4).
Output).

As a result, according to the lubricating device 100 described above, the following effects can be obtained. When the rod body 1 contracts, air flows in from the nozzle 13 and the front end of the lubricant liquid moves into the nozzle, so that the lubricant can be prevented from dripping at the time of rest. When the rod 1 is extended, the pressure of the lubricant in the cylinder 9 increases while the air at the nozzle tip is pushed out. For this reason, a slight delay occurs in the time until the lubricant is discharged from the nozzle end, and this delay time is offset by the time required to raise the lubricant to a predetermined pressure. As a result, a high ejection speed close to the predetermined speed can be obtained at the time of discharging the lubricant, and the discharge of the lubricant at a speed lower than the required predetermined speed can be reduced. Further, since the cross-sectional area S of the cylinder 9 in the direction orthogonal to the axis is smaller than the cross-sectional area A of the rod 1, the pressure of the lubricant in the cylinder can be made higher than the pressure generated by the rod 1 itself. Discharge can be performed at a higher pressure.

By directly attaching the lubricant to the surface to be lubricated, an air pump for transporting the lubricant becomes unnecessary. Further, when the pressure of the lubricant in the cylinder is set to a high pressure, the compression of the lubricant and the expansion of the pump chamber of the cylinder 9 and the like cannot be ignored. The discharge amount can be obtained with high accuracy. Furthermore, since the amount of lubricant attached to the lubricating surface can be easily adjusted by controlling the coil current, a fixed quantity valve is not required. As a result, a compact lubricating device having a simple structure can be realized.

The control device 27 detects the number of rotations of the rotating body to which the lubricant is to be supplied, and determines a current value corresponding to the detection signal, a current supply frequency corresponding to the detection signal, or both. In such a case, the current may be supplied to the coil 23 to adjust the lubricant discharge amount. In this case, it becomes possible to supply an optimal lubricant that changes with the rotation speed,
It is possible to prevent the excessive supply of the lubricant and always obtain the optimal lubrication effect. For example, the rotational speed of the shaft (rotating body) of the bearing to which the lubricant is to be supplied is detected by an encoder or the like, and the obtained rotational speed is input to the control device 27. The control device 27 adjusts the current value of the driving current to the coil 23 and the operating frequency so that the lubricant is supplied more when the rotation speed is high and less when the rotation speed is low, and outputs the coil current. In this case, the control device 27 corresponds to a lubricant discharge amount adjusting unit.

Next, a second embodiment of the lubricating device according to the present invention will be described. FIG. 6 is a diagram showing a circuit configuration of a coil control device in the lubrication device of the present embodiment. The lubricating device according to this embodiment has the same configuration as that of the lubricating device according to the first embodiment except for the control device, and redundant description will be omitted.

The control device 28 of the present embodiment is connected to the coil 23 for extending the rod 1 made of the giant magnetostrictive element shown in FIG. 1, and controls the application of current to the coil 23. As shown in FIG. 6, the control device 28 includes a high-voltage power supply 61 for steeply increasing the applied current, a low-voltage power supply 62 for obtaining a required amount of lubricant discharged after the rising of the applied current, (FETs) Tr1 and Tr2 for switching the power supplies 61 and 62 of the transistors according to the outputs from the comparators 63 and 64
And The operation of the control device 28 will be described. When both Tr1 and Tr2 are first turned on, current is supplied to the coil by the high voltage power supply 61 and the low voltage power supply 62. At this time, as shown in the current waveform in FIG.
The coil current sharply rises to the initial pressure setting level (first current value). The rising characteristic of the coil current is expressed by equation (5).

I (t) = E / r · [1−exp {−rt / L}] (5) where I: current E: voltage r: resistance L: inductance. For example, assuming that the resistance r of the coil is 1.7 [Ω], the inductance L is 5 [mH], and the voltage is 200 [V], the current I (t) is calculated by the above equation.
It reaches 5 [A] in 28 [μs].

As shown in FIG. 7, if 5 [A] is set as the initial pressure setting level, the current becomes 5
Upon detecting that [A] has been reached, Tr1 is turned off. Then, current is supplied to the coil only from the low-voltage power supply side. The voltage E of the low-voltage power supply at this time is obtained as follows. The cross-sectional area of the nozzle is Sn [mm ² ], the cross-sectional area of the cylinder internal volume is Sc [mm ² ], and the elongation of the giant magnetostrictive element is Δ
Assuming that L [mm / A], the required discharge speed is v [mm / A].
s], the elongation speed vm [m of the giant magnetostrictive element required to obtain
m / s] is expressed by equation (6).

Vm = v · Sn / Sc (6) The required current increase rate I ′ [A / s] is given by (7)
It is expressed by an equation. I ′ = vm / ΔL (7)

For example, if the sectional area Sn of the nozzle is 0.008
[Mm ² ] and the required discharge speed v is 50,000 [mm /
s] and the cross-sectional area Sc of the cylinder inner volume is 30 [mm ² ].
Then, the required elongation speed vm of the giant magnetostrictive element is 13.
3 [mm / s]. At this time, assuming that the extension ΔL of the giant magnetostrictive element is 0.01 [mm / A], the required current increase rate ΔI is 1330 [A / s]. If the discharge amount is 1 [mm ³ ], the required increase in current ΔI is ΔI = 1 / (Sc · ΔL) = 3.3 [A], and the time T required to reach this current value is T = 3.3 / 1330 = 2.48 × 10 ⁻³ [s] By substituting the above parameters into the equation (5), the voltage E becomes 18.3 [V]. Therefore, under the above conditions, the voltage E may be set to the voltage value of the low-voltage power supply 62.

By setting the voltage of the low-voltage power supply to a voltage value determined according to the discharge speed, a desired discharge speed can be obtained with a given pump. Then, when the time T has elapsed after reaching the current value of the initial stress setting level, that is, when a required discharge amount is obtained, Tr2 is also turned off to cut the coil current. This T
By generating the coil current by the on / off operation of r1 and Tr2 at a predetermined operation frequency, the lubricant can be intermittently discharged from the lubrication device. According to this method, it is possible to configure the power saving and the cost at a lower cost than the dropper method in which the current is controlled by the current feedback and the pulse width control method. Although the circuit of the present embodiment can automatically switch and turn off the voltage value according to the current value of the coil, the circuit may switch and turn off the voltage value using a timer. Further, in FIG. 7, the current is turned off after the current value reaches the required discharge amount level. At this time, preferably, the current value is gradually reduced so that cavitation does not occur in the pump chamber. desirable.

FIG. 8 is a graph showing an example of a change in the coil current with respect to the elapsed time. In this case, the inductance L of the coil is 5 [mH] and the resistance r is 1.7.
[Ω]. As shown in FIG.
By turning on both 1 and Tr2 and applying a high voltage,
Start the coil current steeply. Next, Tr1 is turned off, and the lubricant is discharged at a predetermined discharge speed using only the low-voltage power supply. FIG. 8 shows that the voltage value of the low-voltage power supply is 24 [V], 1
The voltage is displayed in three types of 8 [V] and 12 [V]. When the voltage E in the above-described calculation example is 18.3 [V], it is substantially equal to the above calculation example of 18 [V].

Next, a third embodiment of the lubricating device according to the present invention will be described. The lubricating device according to the present embodiment is capable of monitoring an operation state of the pump by detecting an abnormality such as lubricant leakage or clogging.

First, the properties of the magnetostrictive element will be described. Representative properties of the magnetostrictive element include the following two properties. One is a so-called Joule effect, in which a magnetostrictive element is distorted by a magnetic field acting thereon. As described above, a magnetostrictive pump that expands the magnetostrictive element by applying a magnetic field to the magnetostrictive element utilizing this property and thereby drives the piston is a magnetostrictive pump.

The other one is called the Villarri effect. The Vilarli effect is an effect in which the magnetic permeability of a magnetostrictive element changes according to the stress applied to the magnetostrictive element. When the magnetostrictive element is provided with a driving coil, the inductance of the coil changes. Generally, in a giant magnetostrictive material, when the stress becomes about 1 [MPa], the inductance becomes about 30% smaller than the inductance when the stress is zero.

By utilizing this Birrari effect as follows,
Anomaly detection can be performed. That is, when the lubrication device is operating normally, the pressure in the cylinder is, for example, 4
[MPa], and if the cross-sectional area of the piston is 1/4 of the cross-sectional area of the giant magnetostrictive element, the stress of the giant magnetostrictive element is 1
[MPa]. In this case, the reduction rate of the inductance of the coil including the giant magnetostrictive element is a reduction rate corresponding to this stress, that is, about 30%.

Here, when an abnormality occurs in the lubrication device and the nozzle is clogged, the pressure in the cylinder is increased to 30 to 4
At a high pressure of 0 [MPa], the stress of the giant magnetostrictive element increases correspondingly, and as a result, the inductance reduction rate of the coil becomes about 40%. Conversely, when a lubricant leaks inside the giant magnetostrictive pump, the pressure in the cylinder and the stress of the giant magnetostrictive element become substantially zero, and the reduction rate of the inductance of the coil also becomes substantially zero. Thus, when an abnormality occurs in the operation state of the giant magnetostrictive pump of the lubricating device, the inductance reduction rate of the coil greatly changes from 0% to 40%.

By the way, the rising characteristic of the current flowing through the coil is expressed by the equation (5) as described above. (5)
According to the formula, as shown in FIG. 9, when the decrease in the inductance L of the coil is small, the current I flowing through the coil rises later than the design value, and conversely, when the decrease in the inductance L of the coil is large, , The current I rises earlier than the design value. Thus, by detecting the rise time of the current flowing through the coil, the rate of decrease of the inductance of the coil, that is, the stress of the giant magnetostrictive element can be detected.

As shown in FIG. 10, the current flowing through the coil 23 is monitored by the detecting resistor 67 and the current judging device 68 to judge whether the operating state of the giant magnetostrictive pump is good or not. The detection resistor 67 and the current determination device 68 correspond to a current measurement unit and an abnormality determination unit. That is, if the rise time of the current flowing through the coil 23 is approximately equal to the design value, it can be understood that the giant magnetostrictive pump is operating well. If the rise time of the current is earlier than the design value, the The pressure in the cylinder 9 increases due to clogging or the like, and the giant magnetostrictive element 1
It can be seen that a large stress is generated at the point. Also, if the rise of the current is later than the design value, it can be seen that a low stress is generated in the giant magnetostrictive element 1 due to a problem such as leakage of the lubricant from the lubricant flow path.

As described above, since there is a close relationship between the pressure in the cylinder 9 and the discharge of the lubricant from the nozzle 13, the rise of the current in the coil 23 deviates from the designed target value. It is estimated that the ejection of the lubricant from the nozzle 13 is abnormal. Here, taking as an example the case where the lubricating device of the present invention is used as a device for supplying a lubricant to a rolling bearing of a high-speed spindle, when a deviation from a target value is detected in a rising characteristic of a coil current, In addition, a feedback control such as transmitting an abnormal signal from the current determination device 68 and urgently stopping the rotation of the high-speed spindle can be performed.

Next, a fourth embodiment of the lubricating device according to the present invention will be described. In the present embodiment, the completion of air removal from the nozzle can be detected. As described above, the inductance when the stress is 1 [MPa] is reduced by about 30% from the inductance when the stress applied to the giant magnetostrictive element is zero due to the Villari effect, which is one of the main properties of the magnetostrictive element. I do.

From this relationship, the rising speed of the current flowing through the coil shown in FIG. 11 is related to the stress applied to the giant magnetostrictive element, that is, the pressure in the cylinder. FIG. 12 is a diagram showing the relationship between the current measuring device 68 and the current measuring device 68 and the air mixing determining device.
By detecting the current flowing through the coil as shown in (2), it is possible to determine the completion of air release of the giant magnetostrictive pump.

That is, when detecting the completion of air bleeding at the time of starting the lubricating apparatus, the rising characteristic of the current is compared with the characteristic in the normal state. It is determined that air remains in the agent flow path. When air remains, the control device 27 shown in FIG. 1 operates the giant magnetostrictive pump so as to drive the piston 7 in a cycle faster than the steady state and with a large stroke in order to bleed air in a short time. Thereafter, when the air bleeding is completed, the operation of the giant magnetostrictive pump is returned to the steady state. Thereby, for example, at the time of the first operation of the lubrication device or the start of the morning, air bleeding can be automatically completed in a short time.

The lubricating apparatus according to each of the embodiments described above can be suitably applied to, for example, a cartridge spindle of a machining center that requires high precision and high speed rotation. Further, as the magnetostrictive material forming the rod body, a pump utilizing the expansion and contraction action can be formed in the same manner by using a magnetostrictive material having bidirectional characteristics in addition to the above-described giant magnetostrictive material having positive characteristics. Then, instead of the above current value, a voltage value proportional to the current value is measured with a voltmeter to measure the voltage drop of the detection resistor shown in FIG. 10, and based on the obtained voltage value, an abnormality determination or a determination of completion of air release is made. May go.
In this case, measurement and determination can be performed simply.
Further, instead of the current value, the strength of the magnetic field proportional to the current value may be measured using a Hall element or the like, and the abnormality determination or the completion of air bleeding may be determined based on the obtained magnetic field value. In this case, it is preferable to dispose the Hall element in the vicinity of the rod 1, whereby the expansion and contraction operation of the rod can be more directly detected, the measurement accuracy can be improved, and the judgment accuracy can be improved. In addition, as another application of the present apparatus, for example, supply of a cutting oil in semi-dry processing or the like can be considered.

[0061]

The lubricating apparatus according to the present invention has a
Since air flows in from the nozzle and the tip of the lubricant moves into the inside of the nozzle, it is possible to prevent the lubricant from dripping at the time of rest.
Since the lubricant pressure in the cylinder is increased while the air at the nozzle tip is extruded, a high ejection speed can be stably obtained from the initial stage of ejection. In addition, since the cross-sectional area of the cylinder in the direction perpendicular to the axis is smaller than the cross-sectional area of the rod, the pressure of the lubricant in the cylinder can be higher than the pressure generated by the rod, and the lubricant can be supplied at high speed. Can be ejected. Therefore, a pump for increasing the pressure of the lubricant is not required, and the apparatus can be downsized. Furthermore, since the value of the current applied to the coil is corrected based on a discharge amount variation element such as compression of the lubricant, expansion of the cylinder, and suction of air, a desired discharge amount can be obtained with high accuracy.

By detecting the operating state of the lubricating device, it is possible to monitor whether or not the supply of the lubricant is performed correctly, and to obtain a lubricating device for a high-speed spindle or the like which requires high reliability. it can. Further, by detecting the completion of the air bleeding in the pump, the air bleeding can be completed in a short time to return to a normal operation state, and a lubricating device with good workability can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lubrication device according to the present invention.

FIG. 2 is a diagram showing another nozzle shape.

FIG. 3 is a block diagram illustrating calculation of a correction amount for a current applied to a coil, which is performed by a control device to obtain a constant discharge amount.

FIG. 4 is a time chart showing a temporal relationship between a current applied to a coil and a lubricant discharge.

FIG. 5 is a block diagram illustrating an example of a current control function for each discharge amount.

FIG. 6 is a diagram showing a circuit configuration of a coil control device in a lubrication device according to a second embodiment.

FIG. 7 is an explanatory diagram showing a coil current waveform accompanying the operation of a transistor.

FIG. 8 is a graph showing an example of a change in a coil current with respect to an elapsed time.

FIG. 9 is an explanatory diagram showing rising characteristics of a coil current in an abnormal state and a normal state.

FIG. 10 is a diagram showing a configuration for detecting a coil current.

FIG. 11 is an explanatory diagram showing rising characteristics of a coil current after air is mixed and after air is completely removed.

FIG. 12 is a diagram showing a coil current detection state from the state of air mixing to the completion of air bleeding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rod (giant magnetostrictive material) 1a One end 1b The other end 7 Piston 9 Cylinder 11 Pump chamber 13 Nozzle 15 Inlet 17 Suction valve 23 Coil 27, 28 Control device 67 Detecting resistance 68 Current judging device 100 Lubricating device

Claims (7)

[Claims] A magnetic field is applied to and removed from a rod made of a magnetostrictive material to expand and contract the rod, and the rod is pressurized using a magnetostrictive pump having a pump chamber for pressurizing a lubricant by the expansion and contraction. A check valve disposed in the middle of a flow path for supplying a lubricant to the magnetostrictive pump, for preventing the lubricant from flowing out of the magnetostrictive pump; A nozzle having a flow path cross-sectional area smaller than a lubricant flow path cross-sectional area of the check valve, the lubricating apparatus being provided on the agent discharge side. 2. A pump chamber comprising one end fixed to the rod body, a piston connected to the other end, and a piston slidably provided inside the cylinder, and an inner surface of the cylinder. The lubricating apparatus according to claim 1, wherein a cross-sectional area of the lubricating body is smaller than a cross-sectional area of the rod. 3. The reduced volume of the pump chamber due to the extension of the rod is determined by the amount of air flowing in from the nozzle when the rod is contracted and the volume of the internal space between the check valve and the nozzle outlet. The volume reduction due to the compression of the lubricant, the increase in the internal volume due to the pressure deformation of the components constituting the internal volume, and the required amount of the lubricant to be discharged are equal to the sum of the required amount. 2. The lubricating device according to 2. 4. The magnetostrictive pump includes a coil for applying a magnetic field, and a control device that controls expansion and contraction of the rod by controlling a current supplied to the coil. The control device includes an initial excitation of the coil. Sometimes, a current is supplied until the pressure of the lubricant in the pump chamber at which a desired discharge speed is obtained by the magnetostrictive pump is reached, and after reaching the pressure, the pressure of the lubricant is kept constant according to the discharge amount of the lubricant. The lubricating device according to any one of claims 1 to 3, wherein a current for holding the lubricating oil is supplied, and the supplied current is turned off after a desired lubricant discharge amount is obtained. . 5. A rotation speed detecting means for detecting a rotation speed of a rotating body to which the lubricant is supplied, and a current value of a current supplied to the coil according to the rotation speed detected by the rotation speed detecting device. The lubricating device according to any one of claims 1 to 4, further comprising: a lubricant discharge amount adjusting means for setting an operating frequency. 6. A measuring means for measuring one of a current value supplied to the coil, a voltage value proportional to the current, and a magnetic flux value generated by the current, and a measured value for an elapsed time measured by the measuring means. Is provided with abnormality determining means for determining whether an abnormality has occurred by comparing the measured value with a normal measurement value, and generating an abnormality signal when the abnormality determining means determines that an abnormality has occurred. The lubricating device according to any one of claims 1 to 5. 7. A measuring means for measuring one of a current value supplied to the coil, a voltage value proportional to the current, and a magnetic flux value generated by the current, and a measured value for an elapsed time measured by the measuring means. Is provided with air mixing determining means for determining the presence or absence of air mixing by comparing with a measured value at the time of non-air mixing, until the air mixing determining means determines that there is no air mixing at the start of operation of the lubrication device. The lubricating device according to any one of claims 1 to 5, wherein a current supplied to the coil is increased or a current supply frequency is increased.