JP7263125B2 - Abrasion amount estimator of seal part and machine tool - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wear amount estimating device for a seal portion and a machine tool.

In recent years, machine tools are required to be further automated, and as one solution, it has been proposed to mount a robot inside the machine tool. By using an in-machine robot, it is possible to automate many tasks such as attachment and detachment of tools and workpieces, cleaning of the inside of the machine, tools and workpieces, prevention of entanglement of chips, and prevention of chattering of workpieces.

When a robot is mounted inside a machine tool, the in-machine robot must be resistant to chips and cutting water, and for this reason, contact-type rotary seals are required for the rotary mechanism of the joints of the in-machine robot. However, the contact-type rotary seal gradually wears out over time, and if left as it is, chips and cutting water will eventually enter the inside of the rotary mechanism from the outside.

In Patent Document 1, for the purpose of preventing problems caused by foreign matter entering and solidifying in the sliding gap between the rotating shaft portion and the fitting hole, a fluid is placed in the sliding gap on the downstream side. A rotary joint is described with a lip seal to selectively seal only directional flow and pressurizing means to pressurize the pressure in the sliding gap.

In Patent Document 2, for the purpose of performing a leakage inspection of a fluid machine capable of inspecting leakage of the housing due to changes in seal characteristics, gas is enclosed in the housing, the amount of leakage is detected, and based on the amount of leakage, A step of determining whether the housing is acceptable, a step of releasing the gas sealed in the housing to the outside of the housing to reduce the pressure in the housing to near atmospheric pressure, and a step of filling the gas in the housing again to reduce the amount of leakage. Detecting and determining whether the housing is acceptable based on the amount of leakage is described.

In Patent Document 3, for the purpose of diagnosing the abnormality of the sealing device and the deterioration cause and degree of deterioration that is the cause of the abnormality, a detector group such as a pressure system and a flow meter, and a detector group connected to and incorporated It is described that it has a computer that calculates the seal flow rate in an assumed state using a calculation model of the seal device, and detects signs of abnormality by comparing the calculated seal flow rate and the actual seal flow rate when it is assumed that there is no abnormality. It is

Patent Document 4 discloses a capacitive leak sensor, a reference capacity capacitor connected in parallel to the leak sensor, and a leak A leak detection device for a shaft sealing device is described that includes a differential amplifier that detects the difference in capacitance between a sensor and a reference capacitance capacitor.

JP 2014-9720 A JP 2007-78630 A JP-A-2001-241550 JP-A-5-45246

As mentioned above, contact-type rotary seals wear little by little over time, so it is extremely important to understand the state of wear and to be able to perform maintenance before chips and cutting water enter from the outside. be.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus capable of estimating the amount of wear of a contact type rotary seal and thereby clarifying the timing of maintenance.

A wear amount estimating apparatus for a seal portion of the present invention is a device for estimating the wear amount of a seal portion of a rotating mechanism portion provided in a machine tool, wherein the seal portion is inserted into the rotating mechanism portion from the outside. Compressed air is supplied to the inside of the rotary seal, and the pressure is adjusted by the pressure adjusting means for adjusting the pressure of the compressed air and the pressure adjusting means. The amount of wear of the rotary seal is determined based on the air leakage detection means for detecting air leakage of the compressed air, the pressure value adjusted by the pressure adjustment means, and the air leakage detected by the air leakage detection means. estimating means for estimating, wherein the pressure adjusting means increases the pressure of the compressed air from an initial pressure to a first pressure, and further increases the pressure from the first pressure when the air leakage detecting means detects no air leakage; Increase to a second pressure .

In one embodiment of the present invention, in an unworn state, the rotary seal maintains a contact state when the pressure of the compressed air is a predetermined pressure or less, and there is no air leakage from the inside to the outside. It becomes a non-contact state, and air leakage of the said compressed air arises.

In another embodiment of the present invention, it further comprises storage means for storing a correspondence relationship between the wear amount of the rotary seal and the pressure value at which air leakage occurs, and the estimation means stores the correspondence relationship stored in the storage means. Based on this, the amount of wear of the rotary seal is estimated.

In yet another embodiment of the invention, said air leak detection means is a pressure gauge or a flow meter.

Further, a machine tool of the present invention includes any one of the wear amount estimating devices for seal portions described above, and an in-machine robot having the seal portions provided at joints.

ADVANTAGE OF THE INVENTION According to this invention, the wear amount of a contact-type rotary seal can be estimated. Further, according to the present invention, the timing of maintenance can be clarified based on the estimated amount of wear, and the intrusion of chips and cutting water generated during machining can be prevented more reliably.

It is a lineblock diagram of a machine tool of an embodiment. It is a cross-sectional view of the rotary seal of the embodiment. FIG. 4 is an illustration of wear of the rotary seal of the embodiment; It is a graph showing the relationship between the pressure and air leakage of the unworn rotary seal of the embodiment. It is a graph showing the relationship between the pressure of the worn rotary seal of the embodiment and the air leakage. 1 is a configuration block diagram of an apparatus according to an embodiment; FIG. 3 is a circuit diagram of pressure adjusting means and air leakage detecting means of the embodiment; FIG. It is a processing flowchart of the embodiment.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a machine tool 10. As shown in FIG. In the following description, the rotation axis direction of the work spindle device 14 is called the Z-axis, the moving direction perpendicular to the Z-axis of the tool rest 4 is called the X-axis, and the direction perpendicular to the Z-axis and the X-axis is called the Y-axis.

The machine tool 10 is a machine that cuts a workpiece with a tool. Specifically, the machine tool 10 has a turning function of cutting the work 3 by applying a turning tool while rotating the work 3 and a milling function of cutting the work with the rotary tool.

The periphery of the machine tool 10 is covered with a cover (not shown). A space defined by this cover serves as a processing chamber in which the workpiece 3 is processed. By providing the cover, chips and the like are prevented from scattering to the outside. The cover is provided with at least one opening and a door (both not shown) for opening and closing the opening. An operator accesses the inside of the machine tool 10, the workpiece 3, etc. through this opening. A door provided in the opening is closed during processing. This is to ensure safety, environmental friendliness, and the like.

The machine tool 10 includes a work spindle device 14 that holds a work 3 rotatably, and a tool post 4 that holds a tool 100 . The work spindle device 14 includes a headstock installed on the base 22 and a work spindle attached to the headstock. The work spindle is provided with a chuck for gripping and releasably holding the work 3, and the work 3 to be gripped can be appropriately replaced. The figure illustrates a configuration for gripping/releasing the workpiece 3 by opening and closing three claws provided on the chuck. may be configured to grip/release the workpiece 3 by opening and closing the . The work spindle rotates around a work rotation axis extending in the horizontal direction (Z-axis direction).

The tool post 4 holds a turning tool, for example, a tool called a bit. The tool post 4 and the cutting tool are linearly movable in the XZ-axis direction by a drive mechanism.

A discharge mechanism for collecting and discharging chips scattered during cutting is provided at the bottom of the processing chamber. Various forms are conceivable as the discharge mechanism. For example, the discharge mechanism is configured by a conveyor or the like that conveys chips that have fallen due to gravity to the outside.

The machine tool 10 includes a control device that performs various calculations. A control device in the machine tool 10 is also called a numerical control device (NC), and controls driving of each part of the machine tool 10 according to instructions from an operator. The control device includes, for example, one or more CPUs that perform various calculations, a memory that stores various control programs and control parameters, an input/output interface, an input device, and an output device. An input device is, for example, a touch panel or a keyboard, and an output device is a liquid crystal display, an organic EL display, or the like. Both the input device and the output device may be composed of touch panels. The control device also has a communication function, and can exchange various data such as NC program data with other devices. The control device may include, for example, a numerical control device that calculates the positions of the tool 100 and the workpiece 3 as needed. The control device may be a single device, or may be configured by combining a plurality of arithmetic devices.

In addition, the machine tool 10 of this embodiment includes an in-machine robot 20 . The on-board robot 20 includes joints, joints, and a hand 20d. In this embodiment, the robot arranged at a predetermined position in the processing chamber is called an in-machine robot. The predetermined position does not necessarily mean a fixed position, but the concept includes a position that can be moved to a desired position during machining of the workpiece or other times even if it is initially placed at a certain position. By driving and controlling the in-machine robot 20, it is possible to attach and detach tools and workpieces 3, clean the inside of the machine, tools and workpieces 3, prevent entanglement of chips, prevent chattering of workpieces 3, and the like.

A rotary mechanism portion, such as a joint, of the in-machine robot 20 is provided with a seal portion for preventing chips and cutting water from entering from the outside.

FIG. 2 is a cross-sectional view showing an example of a contact-type rotary seal used for joints of the on-board robot 20. As shown in FIG. A contact type rotary seal 40 is provided between the rotary shaft 30 and the fixed portion 32 . Specifically, a groove 34 is formed in the surface of the fixed portion 32 facing the rotary shaft 30 , and a rotary seal 40 having a U-shaped or U-shaped cross section is arranged in the groove 34 . In the rotary seal 40, two seal portions, a rotary side seal portion 42 and a fixed side seal portion 44, extend in a U-shape or U-shape so that the outer side is the opening side of the U-shape or U-shape. It has a cross-sectional shape, and a contact portion 46 projecting toward the rotating shaft 30 is provided on the surface facing the rotating shaft 30 at the tip of the rotating side seal portion 42 . The contact portion 46 is formed in a tapered shape so as to gradually taper in the direction from the rotating side seal portion 42 toward the rotating shaft 30 . Further, the rotating seal portion 42 and the stationary seal portion 44 are biased toward the stationary portion 32 and the rotating shaft 30 by an elastic member or the like arranged along the curved inner surface of the rotating seal 40 . That is, the rotary-side seal portion 42 is pressed toward the rotating shaft 30 by the elastic member, and the fixed-side seal portion 44 is pressed toward the stationary portion 32 by the elastic member. In the drawing, the urging by the elastic member is shown as a spring, but it can be configured by a spring member arranged inside the U-shape or U-shape.

Compressed air is supplied through an air path (not shown) to the inside of the joint sealed by the rotary seal 40 to purge air from the inside. This air purge is normally performed at a pressure slightly higher than the atmospheric pressure (hereinafter this pressure will be referred to as P0). The air purge prevents foreign matter such as chips and cutting water from entering from the outside.

In a normal state, the rotating seal portion 42 and the stationary seal portion 44 of the rotary seal 40 are urged toward the rotating shaft side and the stationary portion side by the elastic member, respectively, so that the contact state is maintained even when the air is purged with compressed air, and the seal portion 44 is compressed. Air does not leak to the outside, but when the pressure of the compressed air is increased from P0, the rotating side seal portion 42 is displaced in the direction away from the rotating shaft 30 against the urging force thereof, forming a tapered contact portion. 46 is separated from the rotating shaft 30 and is in a non-contact state, creating a gap. Compressed air then leaks to the outside through this gap. If the tapered contact portion 46 is in an unworn state, the contact surface pressure of the contact portion 46 is sufficiently high. does not occur.

However, since the contact portion 46 is in contact with the rotating shaft 30, the contact portion 46 gradually deteriorates over time, and the contact surface pressure of the tapered contact portion 46 decreases.

FIG. 3 schematically shows how the contact portion 46 wears. 3(a) shows the rotary seal 40 in an unworn state, and FIG. 3(b) shows a partially enlarged sectional view of the contact portion 46. FIG. The tapered contact portion 46 is unworn and has a relatively large contact surface pressure.

FIG. 3(c) shows a partially enlarged cross-sectional view of the contact portion 46 worn from the unworn state. The contact portion of the tapered contact portion 46 is worn, and the contact surface pressure is relatively reduced compared to the unworn state. FIG. 3(d) shows a partially enlarged sectional view of the contact portion 46 further worn from the unworn state. The contact portion of the tapered contact portion 46 is further worn, and the contact surface pressure becomes relatively smaller than in the case of FIG. 3(c).

As described above, when the contact surface pressure of the contact portion 46 decreases as the wear progresses, air leakage may occur even when the pressure of the compressed air is low. That is, if the pressure of the compressed air is P0 in an unworn state, air leakage does not occur. , air leakage occurs at a pressure lower than the pressure P1 at which air leakage occurs in an unworn state. Considering that the contact surface pressure of the contact portion 46 decreases as wear progresses, there is a certain correlation between the amount of wear and the pressure at which air leakage occurs. The wear amount of the contact portion 46, that is, the wear amount of the rotary seal 40 can be estimated from the pressure obtained.

FIG. 4 exemplarily shows the relationship between the pressure of compressed air and air leakage when the rotary seal 40 is not worn. Air leakage does not occur at the air purge pressure P0, and when the pressure is increased from P0, air leakage occurs at the pressure P1, and when the pressure is further increased from P1, the amount of air leakage increases according to the pressure value.

FIG. 5 shows the relationship between compressed air pressure and air leakage when the rotary seal 40 is worn and deteriorated. As the rotary seal 40 wears, the graph showing the relationship between pressure and air leakage shifts to the left in the drawing, and air leakage occurs at lower pressures. Specifically, when the pressure is increased from P0, air leakage occurs at pressure P2 (P0<P2<P1), and when the pressure is further increased from P2, the amount of air leakage increases according to the pressure value. As the rotary seal 40 wears further, the graph shifts further to the left as shown, and air leakage occurs even at pressure P0. This state means that air leakage occurs even when compressed air is purged, and means that the function of preventing the intrusion of foreign matter cannot be exhibited. In the drawing, the slopes of the graphs are assumed to be the same for convenience, but the slopes of the graphs may also change according to wear.

Therefore, in this embodiment, the presence or absence of air leakage is detected when the pressure of the compressed air is temporarily increased to P0 or more of the air purge pressure, and based on the pressure value when the air leakage occurs, the rotary seal 40 Estimate how worn the

FIG. 6 shows a configuration block diagram of the wear amount estimation device in this embodiment. The wear amount estimation device includes pressure adjustment means 50 , air leakage detection means 52 , wear amount estimation means 54 , and storage means 56 .

The pressure adjusting means 50 adjusts the pressure of compressed air for air purging of the rotary seal 40 to increase or decrease. The pressure adjusting means 50 outputs the adjusted pressure value to the wear amount estimating means 54 . The pressure regulating means 50 has a plurality of pressure paths, for example, composed of a plurality of solenoids and a plurality of regulators, and changes the pressure in a plurality of stages by sequentially switching the pressure paths. The pressure adjusting means 50 sequentially increases the pressure from the air purge pressure P0.

The air leakage detection means 52 detects air leakage from the rotary seal 40 . The air leakage detection means 52 outputs the presence or absence of air leakage to the wear amount estimation means 54 . The air leak detection means 52 has, for example, a differential pressure gauge sandwiching a throttle, and detects air flow, that is, presence of an air leak, when a differential pressure ΔP is detected.

The storage means 56 stores in advance the corresponding relationship between pressure values and air leaks as a table 58 based on calculations, experiments, or the like. The graph shown in FIG. 5 is an example of the table 58 stored in the storage means 56. FIG. The table 58 defines the corresponding relationship between the pressure value of compressed air and the amount of air leakage for each amount of wear. Air leakage amount=0 means that there is no air leakage. The table 58 may define the correspondence relationship between the pressure value at which air leaks and the amount of wear. for example,
Air leak pressure PL1 → Amount of wear f1
Air leak pressure PL2 → Amount of wear f2
Air leak pressure PL3 → Amount of wear f3
・・・
It is like

The wear amount estimation means 54 estimates the wear amount of the rotary seal 40 based on the pressure value from the pressure adjustment means 50 and the air leakage detection result from the air leakage detection means 52 . The wear amount estimating means 54 outputs a control signal instructing the pressure adjusting means 50 to further increase the pressure when the detection result output from the air leakage detecting means 52 indicates no air leakage. The pressure adjusting means 50 increases the pressure in accordance with a command from the wear amount estimating means 54 . On the other hand, when the detection result output from the air leak detection means 52 indicates that there is an air leak, the wear amount estimation means 54 updates the table 58 stored in the storage means 56 based on the pressure value output from the pressure adjustment means 50. By referring to it, the wear amount corresponding to the pressure is estimated. The wear amount estimating means 54 displays and outputs the estimated wear amount on the output device of the machine tool.

The wear amount estimation means 54 and the storage means 56 are specifically composed of a CPU and a memory. The wear amount estimating means 54 and the storage means 56 may be configured by a control device that controls the operation of the machine tool 10. In this case, the CPU of the control device functions as the wear amount estimating means 54, A memory functions as storage means 56 . Further, the wear amount estimation means 54 and the storage means 56 may be configured by a control device separate from the control device of the machine tool 10 .

The wear amount estimating means 54 displays and outputs the estimated wear amount on the output device of the machine tool 10, but the output mode of the estimated wear amount is arbitrary. = 1 mm or the like, or the estimated wear amount may be relatively output as, for example, wear amount = small, wear amount = medium, or wear amount = large. Furthermore, when the amount of wear exceeds a certain threshold value, a message to that effect may be output together with the amount of wear, assuming that the rotary seal 40 needs to be replaced. In short, along with the amount of wear, the timing of maintenance based on the amount of wear may be output as a message.

FIG. 7 shows specific examples of the pressure adjusting means 50 and the air leakage detecting means 52. As shown in FIG.

The pressure adjusting means 50 includes a filter 510 , solenoids 520 , 530 , 540 and 560 , regulators 521 , 531 and 541 and check valves 522 , 532 and 542 .

Filter 510 filters compressed air from the compressor and supplies it downstream.

The three solenoids 520 , 530 , 540 are connected in parallel with each other downstream of the filter 510 . A regulator 521 is connected downstream of the solenoid 520 to reduce the pressure of the compressed air to a first pressure. A differential pressure gauge 550 sandwiching a throttle is connected to the downstream side of the regulator 521 via a check valve 522 .

A regulator 531 is connected downstream of the solenoid 530 to reduce the pressure of the compressed air to the second pressure. A differential pressure gauge 550 is connected to the downstream side of the regulator 531 via a check valve 532 .

A regulator 541 is connected downstream of the solenoid 540 to reduce the pressure of the compressed air to a third pressure. A differential pressure gauge 550 is connected to the downstream side of the regulator 541 via a check valve 542 .

Solenoids 520 , 530 , 540 connected in parallel to filter 510 are sequentially ON/OFF controlled by a control signal from wear amount estimating means 54 . That is, first, the solenoid 520 is turned ON, and the solenoids 530 and 540 are turned OFF. As a result, the compressed air from the filter 510 is reduced to the first pressure by the regulator 521 and output. Next, the solenoid 530 is turned ON, and the solenoids 520 and 540 are turned OFF. As a result, the compressed air from the filter 510 is reduced to the second pressure by the regulator 531 and output. Next, the solenoid 540 is turned ON and the solenoids 520 and 530 are turned OFF. As a result, the compressed air from the filter 510 is reduced to the third pressure by the regulator 541 and output. Assuming that the first pressure<the second pressure<the third pressure, the pressure of the compressed air increases stepwise by sequentially turning on the solenoids 520, 530, and 540. FIG. Assuming that the first pressure is the air purge pressure P0, the solenoid 520 is controlled to be ON, and the solenoids 530 and 540 are controlled to be OFF, thereby air purging the rotary seal 40 from the inside.

A rotation mechanism is connected to the downstream side of the differential pressure gauge 550 across the throttle, and a solenoid 560 is connected in parallel. The downstream side of the solenoid 560 is connected to the atmosphere side via a throttle 570 . Solenoid 560 functions as a depressurization valve.

A differential pressure gauge 550 as the air leak detection means 52 measures the differential pressure ΔP between the upstream side and the downstream side of the throttle. When there is no air leakage, there is no air flow, so the differential pressure ΔP=0. However, when air leakage occurs, air flow occurs, so the differential pressure ΔP is detected. That is, ΔP=0 corresponds to no air leakage, and ΔP≠0 corresponds to air leakage. The differential pressure gauge 550 outputs the detected differential pressure ΔP to the wear amount estimating means 54 as an air leakage detection result.

FIG. 8 shows a processing flowchart of this embodiment. In FIG. 8, for convenience of explanation, the solenoid 520 is abbreviated as SOL1, the solenoid 530 as SOL2, the solenoid 540 as SOL3, and the solenoid 560 as SOL4.

First, the wear amount estimating means 54 outputs control signals to SOL1, SOL2, and SOL3, turns ON SOL1, and turns OFF SOL2 and SOL3 (S101). Further, the wear amount estimating means 54 outputs a control signal to SOL4 to ON-control SOL4 (S102). After ON control of SOL4, the system shifts to a standby state for a predetermined short period of time (S103), and after a predetermined short period of time has passed, SOL4 is controlled OFF to end depressurization (S104), and then for a predetermined long period of time. Wait (S105). Specifically, the short and long standby times are stored in the storage means 56 as control parameters.

Since SOL1 is ON-controlled during this long standby state, the first pressure is applied to the inside of the rotary seal 40, and the differential pressure gauge 550 measures the differential pressure ΔP. The measured differential pressure ΔP is output to the wear amount estimating means 54, and the wear amount estimating means 54 determines whether or not the differential pressure ΔP is 0 (S106).

If ΔP is not 0 (NO in S106), air leakage has already been detected when the first pressure is applied. is determined to be excessively large, that is, the wear has progressed considerably (S107).

If ΔP=0 (YES in S106), the wear amount estimating means 54 determines that there is no air leakage, outputs control signals to SOL1, SOL2, and SOL3 again, turns SOL1 OFF, and turns SOL2 ON. and turns off SOL3 (S108). Note that SOL4 remains under OFF control. After that, as in S105, it waits for a predetermined long time (S109).

Since SOL2 is ON-controlled during this long standby state, the second pressure is applied to the inside of the rotary seal 40, and the differential pressure gauge 550 measures the differential pressure ΔP. The measured differential pressure ΔP is output to the wear amount estimating means 54, and the wear amount estimating means 54 determines whether or not the differential pressure ΔP is 0 (S110).

If ΔP is not 0 (NO in S110), air leakage is not detected under the first pressure, and air leakage is detected when the second pressure is applied. , with reference to the table 58, it is determined that the amount of wear of the rotary seal 40 is large, that is, the wear is progressing (S111).

If ΔP=0 (YES in S110), the wear amount estimating means 54 determines that there is no air leakage, outputs control signals to SOL1, SOL2, and SOL3 again, turns SOL1 and SOL2 OFF, and turns SOL3 off. ON control is performed (S112). SOL4 remains under OFF control. After that, as in S105 and S109, it waits for a predetermined long time (S113).

Since SOL3 is ON-controlled during this long standby state, the third pressure is applied to the inside of the rotary seal 40, and the differential pressure gauge 550 measures the differential pressure ΔP. The measured differential pressure ΔP is output to the wear amount estimating means 54, and the wear amount estimating means 54 determines whether or not the differential pressure ΔP is 0 (S114).

If ΔP is not 0 (NO in S114), air leakage is not detected at the first and second pressures, and air leakage is detected when the third pressure is applied. The means 54 determines that the wear amount of the rotary seal 40 is medium, that is, the wear has progressed to some extent (S115).

On the other hand, if ΔP=0 (YES in S114), the wear amount estimating means 54 determines that there is no air leakage and determines that the wear amount of the rotary seal 40 is small, that is, the wear has hardly progressed. (S116).

In this manner, the applied pressure is increased stepwise from the first pressure to the second pressure and further to the third pressure, and the amount of wear of the rotary seal 40 is excessively increased according to the air leakage detection result at that time. Estimation is performed in four stages of large, medium, and small, and the estimation result is output to the output device of the machine tool. As mentioned above, the output form is arbitrary, but for example, if the amount of wear is estimated to be excessive, "The rotary seal is worn out. Please replace it immediately."
If it is estimated that the amount of wear is large, a message such as "The amount of wear of the rotary seal is large. Please replace it."
If it is estimated that the amount of wear is medium, a message such as "The amount of wear of the rotating seal is medium. It will be necessary to replace it soon."
Outputs a message such as "The amount of wear of the rotary seal is small" when it is estimated that the amount of wear is small.
You can output messages such as

The process of FIG. 8 is repeatedly executed at a predetermined control cycle to estimate and output the wear amount of the rotary seal 40 .

According to this embodiment, the inside of the rotary seal 40 is purged with compressed air, and the pressure of the compressed air is used to temporarily increase the pressure of the compressed air to detect the presence or absence of air leakage. The wear amount of the rotary seal 40 can be easily estimated and output. Further, the process of temporarily increasing the pressure of the air purge to estimate the amount of wear can be executed periodically or irregularly at any desired timing. It is possible to grasp the wear amount of the rotary seal 40 and clarify the necessary maintenance timing before the dust enters the inside.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications are possible.

For example, in the present embodiment, the rotary seal 40 having a U-shaped or U-shaped cross-sectional shape as shown in FIG. 2 is exemplified. can be used, and a U-packing type or an oil seal type can be used.

Here, "has directivity" means preventing foreign matter from entering from the outside to the inside of the rotation mechanism. Also, the rotary seal 40 can be multi-staged, and may be combined with a labyrinth seal or the like.

In this embodiment, the applied pressure is adjusted by sequentially turning on SOL1, SOL2, and SOL3. The applied pressure may be adjusted more finely.

Further, in this embodiment, a combination of a throttle and a differential pressure gauge 550 as shown in FIG. 7 is used as the air leakage detection means 52, but an air flow meter may be used.

Further, in the present embodiment, the wear amount of the rotary seal 40 is estimated, but the service life of the rotary seal 40 may be further estimated from the estimated wear amount and output. That is, it is also possible to estimate and output how much life is left from the estimated amount of wear (the point in time when the amount of wear reaches a predetermined threshold is defined as 0).

Furthermore, in this embodiment, the wear amount estimating means 54 periodically or irregularly executes the process shown in FIG. 8 to estimate and output the wear amount of the rotary seal 40. The wear amount estimating means 54 may execute the processing of FIG. In this case, for example, when machining the workpiece 3, the operator instructs the control device as the wear amount estimating means 54 to start executing the process of FIG. 8 prior to the machining, and confirms the output result of the estimated wear amount. After that, processing may be performed. Of course, the control device may automatically perform the processing of FIG. 8 prior to machining, and determine whether or not to perform machining of the workpiece 3 according to the estimated wear amount.

3 work 4 turret 10 machine tool 14 work spindle device 20 in-machine robot 50 pressure adjustment means 52 air leakage detection means 54 wear amount estimation means 56 storage means 58 table 100 tool.

Claims (5)

A device for estimating the amount of wear of a seal portion of a rotating mechanism provided in a machine tool,
The seal portion includes a contact-type rotary seal that prevents foreign matter from entering the inside of the rotary mechanism portion from the outside, and compressed air is supplied to the inside of the rotary seal,
pressure adjusting means for adjusting the pressure of the compressed air;
air leakage detection means for detecting an air leakage of the compressed air when the pressure is adjusted by the pressure adjustment means;
estimating means for estimating the amount of wear of the rotary seal based on the pressure value adjusted by the pressure adjusting means and the air leak detected by the air leak detecting means;
with
The pressure adjusting means increases the pressure of the compressed air from an initial pressure to a first pressure, and further increases the pressure from the first pressure to a second pressure when no air leakage is detected by the air leakage detecting means.
A device for estimating wear of seals. In an unworn state, the rotary seal maintains a contact state when the pressure of the compressed air is a predetermined pressure or less, and there is no air leakage from the inside to the outside. 2. The apparatus for estimating the amount of wear of a seal portion according to claim 1, wherein air leakage of . further comprising storage means for storing a correspondence relationship between the amount of wear of the rotary seal and the pressure value at which air leakage occurs;
3. The wear amount estimating device for a seal portion according to claim 1, wherein the estimation means estimates the wear amount of the rotary seal based on the correspondence stored in the storage means. The wear amount estimating device for a seal portion according to any one of claims 1 to 3 , wherein the air leakage detecting means is a pressure gauge or a flow meter. A wear amount estimating device for a seal portion according to any one of claims 1 to 4 ;
an in-flight robot in which the seal portion is provided at a joint;
Machine tools with

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