JP2005351363A - Lubricant feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant feeder capable of optimally feeding a lubricant also to rolling bearings used for a device operating under irregular operating conditions. <P>SOLUTION: In the rolling bearings rotating while being lubricated under elastic fluid lubrication, the lubricant is optimally fed while monitoring the changes of the properties of a raceway surface and a rolling surface and the deterioration of the lubricant by using a passive sensor. Accordingly, the maintenance and the reliability of operation of the bearings can be increased by efficiently feeding the lubricant in a machine device used in such operating conditions that it is difficult to predict the replacement intervals of the lubricant such as oils and greases which largely depend on natural conditions. Also, in the machine device installed in a place to which an access cannot be made easily, a load on a maintenance person can be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lubricant replenishing device that periodically replenishes a lubricant, and is used, for example, in places where it is difficult to replace lubricants such as grease and oil and the operation state is difficult. The present invention relates to a lubricant replenishing device suitable for a rotating device that uses a rolling bearing under irregular grease lubrication or oil lubrication, for example, a rolling bearing for a wind turbine main shaft and a rolling bearing for a generator.

  Rolling bearings are lubricated with lubricants such as oil and grease, and are designed to ensure reliability over a long period of time under elastic fluid lubrication. However, in recent years, it has been required to ensure reliability over a longer period of time under more severe load, temperature, and lubrication conditions. Therefore, in rolling bearings made with conventional designs, deterioration of lubricants such as oil and grease after long-term use may cause an increase in rotational resistance, increased wear, temperature rise, etc. There is a risk of inviting. This can be done by periodically collecting grease from the rolling bearings in operation and conducting chemical analysis, etc., to inspect the deterioration of the lubricant, or oil that has deteriorated at the time of replacement estimated from experience. It is conceivable to replace the lubricant such as grease or grease.

  However, in order to replace the above inspection and the lubricant such as oil and grease, the entire apparatus using the rolling bearing must be stopped, so that the operating rate is lowered. Conversely, even if the deterioration of the lubricant quality exceeds the limit for some reason during the maintenance cycle, maintenance will not be performed until the next period in principle, which may cause serious trouble that may damage the equipment. May occur.

On the other hand, in order to solve the above-mentioned problem, Patent Document 1 discloses a mechanism that periodically operates a grease circulation pump and constantly supplies new grease to a bearing device to be lubricated. On the other hand, Patent Document 2 proposes a grease supply device that supplies an appropriate amount of grease to a plurality of portions in the bearing device according to the operation cycle of the device.
JP 11-93957 A JP 2000-257792 A JP 2003-176830 A

  The techniques described in Patent Documents 1 and 2 are effective when the operation state of the bearing device can be grasped, and if the grease replacement timing can be correctly predicted based on the experience, the operation interval of the greasing device is appropriately set. Can be determined. However, the prediction of the replacement time is not always correct, and an incorrect replacement time may be set due to an incorrect prediction. As a countermeasure, it may be possible to shorten the grease supply interval from the predicted replacement time, thereby reducing the probability that the deteriorated grease stays in the bearing and avoiding the occurrence of abnormality in the bearing device. This is not economical because of increased grease consumption.

  Patent Document 3 proposes a grease replenishing device that measures the electrical resistance and supplies the lubricant, and this is also an effective method, but this method measures the oil film thickness by the electrical resistance value. More specifically, a resistance is measured by applying a voltage. Therefore, an active sensor is used. This method is not a method of directly measuring the oil film thickness, but can be said to be measured in terms of other amounts of information.

  However, for example, in an apparatus such as a windmill whose operating state greatly depends on the natural environment, the operating state is irregular. Therefore, when the deterioration time of the grease varies depending on the irregular operating state, the active type is not necessarily used. The sensor is not effective.

  The present invention has been made in view of the problems of the prior art, and provides a lubricant replenishing device that can optimally replenish rolling bearings used in devices that operate under irregular operating conditions. Objective.

A lubricant replenishing device according to the present invention includes a first track portion, a second track portion, and a plurality of rolling elements arranged so as to be freely rollable between the first track portion and the second track portion. In a lubricant replenishing device that replenishes a rolling bearing,
A tank for storing lubricant,
A pump for pumping lubricant,
Piping connecting the rolling bearing, the tank and the pump;
A passive type sensor for monitoring the operational status of the rolling bearing;
And a controller that replenishes the rolling bearing with the lubricant in the tank by driving the pump based on an output signal from the sensor.

  The lubricant replenishing device of the present invention monitors the operating status of the rolling bearing using a passive sensor, and the control unit drives the pump based on an output signal from the sensor, thereby Since the lubricant in the tank is replenished to the rolling bearing through the pipe, the optimum lubricant can be replenished even in an apparatus in which it is difficult to predict the deterioration time of the lubricant such as oil or grease.

  Passively measures vibration values of rolling bearings, rotation speed of bearing components, color tone change due to deterioration of lubricants such as oil and grease, volume resistivity change, gas generation, humidity increase due to high moisture content, etc. In some cases, the passive type sensor can perform measurement more appropriately than the active type sensor. Here, an active sensor is an energy different from the characteristic to be measured, such as one that measures the oil film thickness using electrical resistance or one that measures vibration using a laser Doppler velocimeter. Is a sensor that takes out the amount of change in energy as an output and converts it into a characteristic value. In contrast, acceleration vibration is measured with a piezoelectric accelerometer, rotation speed is measured with a tachometer, color tone is changed with an infrared sensor, volume resistivity is changed with an ohmmeter, gas is generated with a gas sensor, and metal wear noise is measured with an ultrasonic sensor. Thus, what measures the changing characteristic value itself can be said to be a passive sensor.

  For example, in a device such as a windmill where the operating state is highly dependent on the natural environment, the operating state is irregular, so if the grease degradation time varies depending on the situation, use a passive sensor. However, more appropriate monitoring is possible. When oil is used as a lubricant in addition to grease lubrication, for example, in Japanese Patent Laid-Open No. 2002-130593, a switching valve is periodically operated to supply oil intermittently. More efficient lubrication becomes possible by using and monitoring and supplying lubricating oil based on the signal. An example of detection using a passive sensor is given below.

(1) If the raceway surface or rolling surface of the rolling bearing becomes rough, the rolling element of the rolling bearing becomes irregular in movement, and therefore the passing vibration of the rolling element is passively measured by a vibration meter, displacement meter or tachometer. An abnormality can be detected by measuring using a mold sensor. When the change in vibration exceeds a threshold value, the pump is operated to supply the lubricant.

(2) When surface roughness occurs on the raceway surface or rolling surface of a rolling bearing, a partial oil film breakage occurs between the raceway surface of the raceway and the rolling surface of the rolling element, and a wide frequency band due to metal contact. The friction noise is generated. Among these frequencies, the frequency in the low frequency range includes the frequency of the mechanical device other than the frictional noise of the rolling bearing, and therefore, a signal in the high frequency range of 5 to 100 kHz is measured using a passive sensor such as an ultrasonic sensor. Thus, it is possible to detect deterioration associated with a change in diameter of the rolling bearing. When the change in vibration exceeds a threshold value, the pump is operated to supply the lubricant.

(3) When a lubricant such as grease deteriorates (oxidizes), the volume resistivity decreases, while the induction rate and induction tangent increase conversely (see JP-A-2003-172494). Oxidation degradation can be accurately detected by measuring any of these using a passive sensor such as an electrode for measuring resistance. In addition, oxidation deterioration can be detected more accurately by measuring while correcting the temperature. When this value exceeds the threshold value, the pump is operated to supply the lubricant.

(4) When lubricants such as grease are deteriorated, hydrocarbons are generated, and hydrogen sulfide and ammonia gas are generated by a tribochemical reaction on the rolling surface. Therefore, these generated gases are lubricated by a passive sensor such as a gas sensor. The deterioration of the agent is detected (see JP 2003-166696 A). When this value exceeds the threshold value, the pump is operated to supply the lubricant.

(5) Since grease changes to a dark color when it deteriorates, a change in color tone from the initial state (new grease) can be detected by a sensor (for example, an optical sensor) that detects the color tone. Alternatively, a space in which grease enters is provided between a light source such as an LED adjacent to the sensor, and the discoloration of the grease is detected by measuring the transmittance of light emitted from the light source. The sensor is arranged near the bearing raceway surface and detects deterioration of grease used for lubrication. Furthermore, when non-ester grease is used, it is known that the absorption near 1710 cm ⁻¹ increases by infrared spectrum analysis when it deteriorates by oxidation, and the oxidation deterioration can be detected by a passive sensor such as an infrared sensor. is there. When this value exceeds the threshold value, the pump is operated to supply the lubricant.

(6) In order to improve detection accuracy, a plurality of detection methods can be combined.
By these methods, the deterioration of the lubricant such as oil or grease is detected, and the lubricant supply pump is driven by the signal to supply the lubricant in the lubricant storage tank to the rolling bearing through the pipe. The new lubricant supplied at this time is supplied to the entire bearing. However, if the supply pump is driven by an output signal from the rotation sensor so that the lubricant pump is driven only while the rolling bearing is rotating, Consumption is suppressed and efficient.

  It is preferable that a pipe for supplying a lubricant is connected to the fixed-side raceway portion of the rolling bearing, and a lubricant supply hole is provided in or near the fixed-side raceway portion.

  The sensor is a sensor that detects a deterioration state of the lubricant, and is either an optical sensor that detects discoloration of the lubricant or a sensor that measures any one of the volume resistivity, dielectric constant, and dielectric loss tangent of the lubricant. Or both are preferable.

  It is preferable that a rotation sensor for detecting a rotation speed is further provided, and that the controller further replenishes the lubricant based on an output signal from the rotation sensor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a lubricant supply device according to the present embodiment. FIG. 2 is a flowchart showing the operation of the lubricant supply device. FIG. 3 is a cross-sectional view of the bearing portion 1. As shown in FIG. 3, the bearing portion 1 that is a rolling bearing is a rolling member that is disposed between an outer ring (track portion) 9, an inner ring (track portion) 12, and both wheels 10 and 12 so as to be freely rollable. It comprises a plurality of rollers 11 and a cage 10 that holds the rollers 11.

  The grease replenishing hole 7 penetrates from the outer diameter surface of the outer ring 9 to a grinding relief portion in the raceway surface of the outer ring 9, and the outer diameter side is connected to the pump P (FIG. 1) via the supply pipe 3. Grease pushed out from the pump P is inserted into the bearing portion 1 through the supply pipe 3 and the grease replenishment hole 7, and the outer ring 9 of the bearing portion 1, the contact surface of the raceway surface 11 of the inner ring 12, the outer ring 9 and the cage 10. It adheres to the contact surface and is appropriately lubricated. The grease sensor 8 is inserted in the radial direction from the outer diameter surface of the outer ring 9 and penetrates the inner diameter surface of the outer ring 9. A sensor detector 8a that penetrates in the vicinity of the raceway surface of the inner diameter surface of the outer ring 9 detects the deterioration state of the grease inside the bearing.

  A lubricant replenishing device that replenishes the bearing portion 1 with a lubricant (here, grease) sends out grease to the bearing portion 1 through a grease tank 2 in which grease is stored and a supply pipe (pipe) 3 from the grease tank 2. Output from the pump P, the motor M that drives the pump P, the grease sensor S (at least one passive sensor of a resistance sensor, a gas sensor, and an infrared sensor) that measures the deterioration of the grease in the bearing 1 and the grease sensor S The sensor signal is input via the wiring 4 to determine the deterioration of the grease, and the signal indicating the rotation speed of the bearing portion 1 output from the rotation sensor RS is input to determine the use state of the device in which it is used. And a control unit 6 including a determination circuit.

  An appropriate amount of grease is stored in the grease tank 2 in advance. The grease stored in the grease tank 2 is guided to the supply pipe 3 by driving the pump P. One of the supply pipes 3 is connected to the grease tank 2, and the other is connected to the bearing portion 1 via the pump P. In the present embodiment, the pump P is configured to be driven by the rotation of the motor M. Further, the bearing portion 1 may have a discharge pipe (not shown) for discharging the grease from the internal space.

  The bearing portion 1 is configured such that grease is supplied to the internal space from the supply pipe 3. Here, the grease supplied from the supply pipe 3 is supplied to the internal space of the bearing portion 1 through the grease supply hole 7 provided in the outer ring 9.

  The operation of the lubricant supply device according to the present embodiment will be further described with reference to FIG. After starting the operation in Step S101, the control unit 6 grasps the initial state of the grease based on the signal output from the grease sensor S in Step S102. In step S103, the control unit 6 grasps the operating state based on the signal output from the rotation sensor RS. Furthermore, in step S104, based on the signal output from the grease sensor S, the control unit 6 determines whether or not the deterioration of the grease has exceeded a threshold value. If so, the bearing unit 1 operates in step S105. It is determined whether it is in the middle. If not in operation, the process returns to step S101 to resume the operation. If in operation, the motor M is driven and controlled in step S106, the pump P is operated to supply grease from the supply pipe 3 (step S107). Here, since the rotation speed signal from the rotation sensor RS is also input to the control unit 6 at the same time, if the motor M is driven while the bearing unit 1 is rotating, the supplied grease is transferred to the bearing unit 1. It is dispersed throughout and can be efficiently lubricated.

  An appropriate amount of grease is set in advance so that the grease detected by the grease sensor S is replaced with the supplied grease by driving the pump P once. Alternatively, the pump P can be set to be driven until the grease detected by the grease sensor S is replaced with the supplied grease. In that case, if the position of the grease sensor S is installed in the vicinity of the grease supply position, the grease detected by the grease sensor S will be immediately replaced, and the supplied grease will not be distributed over the entire bearing. It is desirable that the position of the sensor S is separated with a relative angle in the rotation direction of the bearing portion 1.

  FIG. 4 is a graph showing the relationship between the volume resistivity of the lubricant and the oxidation degree. Since the lubricant has a characteristic that the volume resistivity is reduced when it is oxidized and deteriorated, a relationship between the deterioration degree of the lubricant supplied to the rolling bearing incorporated in the apparatus and the bearing performance is obtained in advance, and the grease sensor S using the resistance sensor is used. Output signal can be set.

  FIG. 5 is a view similar to FIG. 1 showing the lubricant replenishing device according to the second embodiment. The lubricant supply device of the present embodiment can intermittently supply the lubricant. The configuration of FIG. 5 is the same as that of FIG. 1 except that the grease sensor is replaced with an acceleration sensor (also referred to as a vibration sensor, which is a passive sensor) VS, and thus description of the common configuration is omitted. To do. However, a temperature / humidity sensor may be provided in addition to the rotation speed sensor RS.

  In the present embodiment, the control unit 6 measures the vibration of the bearing unit 1 that is a rolling bearing using the acceleration sensor VS, and extracts only a high frequency component of 5 to 100 kHz in the vibration through a filter, Lubricant is supplied at predetermined operation intervals by driving the pump P based on the signal.

  FIG. 6 is a diagram illustrating an example in which the lubricant replenishing device according to the third embodiment is applied to a spindle device of a machine tool. In FIG. 6, the spindle device 61 of the machine tool supports a spindle 69 with respect to a housing 85 by four rolling bearings 71. The grease stored in the grease tank 2 is guided to the switching valve 70 through the supply pipe 3 by driving the pump P, and is taken into the main shaft device 61 from there through the pipe 63, and each of the grease is stored through the nozzle 65. It is supplied to the rolling bearing 71.

This embodiment is also an example in which lubricating oil or grease is intermittently replenished, and the vibration of the rolling bearing 71 is measured using the vibration sensor VS, and control is performed based on the frequency component of the cage as described above. The part 6 drives the pump P to supply the lubricant. For example, the frequency fc of the cage is expressed by the following mathematical formula.
fc = (fr / 2) (1- (Da / dm) cos α) [Hz]
fr: Inner ring rotational speed [Hz]
Da: Rolling element diameter [mm]
dm: pitch circle diameter [mm]
α: Contact angle of rolling bearing [degree]
Instead of the vibration sensor, an ultrasonic sensor that measures ultrasonic waves of 5 to 100 kHz may be used.

  It is also possible to measure the rolling element passing frequency instead of the cage frequency. Also for this vibration, the absolute value of the amplitude, the fluctuation value of the amplitude, the fluctuation value of the frequency, the value of the rotation unevenness, and the like can be used as the determination value.

  According to the present embodiment described above, in a rolling bearing that rotates while being lubricated under elastohydrodynamic lubrication, while monitoring changes in the properties of the raceway surface and the rolling surface and deterioration of the lubricant using a passive sensor, Lubricant can be replenished optimally. Therefore, it is possible to efficiently supply lubricant in machinery and equipment that is used in operating conditions where it is difficult to predict the replacement time of lubricants such as oil and grease, which greatly depend on natural conditions, and to improve maintenance and operational reliability. Can be improved. Furthermore, in a mechanical device installed in a place where access is not easy, the burden on the maintenance worker can be reduced.

  In the above-described embodiment, the ball bearing is taken as an example. However, the present invention is not limited to this, and the first and second track portions such as a ball screw, a linear guide, and a linear ball bearing are used. The present invention can be applied to a lubricant reinforcing device for a rolling bearing having a plurality of rolling elements interposed between the raceway portions so as to be freely rollable and lubricated with a lubricant such as oil or grease and operating under elastic fluid lubrication.

  The present invention has been described above with reference to the embodiments. However, the present invention is not limited to the above-described embodiments, and can of course be changed or improved within the scope of the invention.

It is a schematic block diagram which shows the lubricant supply apparatus concerning this Embodiment. It is a flowchart which shows operation | movement of a lubricant supply apparatus. 1 is a cross-sectional view of a bearing portion 1. It is a graph which shows the relationship between the volume resistivity of a lubricant, and an oxidation degree. . It is a figure similar to FIG. 1 which shows the lubricant supply apparatus concerning 2nd Embodiment. It is a figure which shows the example which applied the lubricant supply apparatus concerning 3rd Embodiment to the main shaft apparatus of a machine tool.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bearing part 2 Grease tank 3 Supply pipe 4 Wiring 6 Control part 7 Grease supply hole 8 Grease sensor 8a Sensor detection part 9 Outer ring 10 Cage 11 Roller 12 Inner ring 61 Main shaft device 63 Piping 65 Nozzle 69 Main shaft 70 Switching valve 71 Bearing 85 Housing M Motor P Pump RS Rotation sensor RS Rotation speed sensor S Grease sensor VS Acceleration sensor

Claims (4)

Lubricant is supplied to a rolling bearing having a first raceway portion, a second raceway portion, and a plurality of rolling elements arranged so as to be freely rollable between the first raceway portion and the second raceway portion. In the lubricant supply device,
A tank for storing lubricant,
A pump for pumping lubricant,
Piping connecting the rolling bearing, the tank and the pump;
A passive sensor for monitoring the operating status of the rolling bearing;
A lubricant replenishing device comprising: a controller for replenishing the rolling bearing with the lubricant in the tank by driving the pump based on an output signal from the sensor. .   The piping for replenishing lubricant is connected to the raceway portion on the fixed side of the rolling bearing, and a lubricant replenishment hole is provided in or near the raceway portion on the fixed side. Lubricant replenishment device.   The sensor is a sensor that detects a deterioration state of the lubricant, and is either an optical sensor that detects discoloration of the lubricant or a sensor that measures any one of the volume resistivity, dielectric constant, and dielectric loss tangent of the lubricant. 3. The lubricant replenishing device according to claim 1 or 2, wherein both are both. 4. The apparatus according to claim 1, further comprising a rotation sensor that detects a rotation speed, wherein the controller further replenishes the lubricant based on an output signal from the rotation sensor. The lubricant replenishing device described.

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