JP2020193678A - Device for estimating abrasion amount of seal part, and machine tool - Google Patents

Abstract

To provide a device capable of estimating an abrasion amount of a contact type rotary seal to clarify timing for maintenance.SOLUTION: A contact type rotary seal 40 is placed on joints of a robot of a machine tool. The inside of the rotary seal 40 is air purged with compressed air. When an abrasion amount of the rotary seal 40 is estimated, the pressure of the compressed air is temporarily increased to detect the presence or absence of air leakage. When a contact part 46 of the rotary seal 40 is worn, air leakage occurs at a pressure value corresponding to the abrasion amount. When an air leakage is detected, the abrasion amount of the rotary seal 40 is estimated and output based on the relation between a predetermined abrasion amount and the air leakage.SELECTED DRAWING: Figure 2

Description

The present invention relates to a wear amount estimation 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 the in-flight robot, many operations such as attachment / detachment of tools and workpieces, cleaning of in-flight tools and workpieces, prevention of wrapping of chips, and prevention of chattering of workpieces can be automated.

When a robot is mounted in a machine tool, the in-flight robot must be durable against chips and cutting water, and therefore a contact-type rotary seal is required for the rotation mechanism of the joint of the in-flight robot. However, the contact-type rotary seal gradually wears over time, and if left as it is, chips and cutting water will eventually enter the inside of the rotary mechanism from the outside.

Patent Document 1 describes the downstream side of the fluid in the sliding gap for the purpose of preventing a defect caused by foreign matter being mixed in the sliding gap between the rotating shaft portion and the fitting hole and being deposited and solidified. A rotary joint is described that includes a lip seal that selectively seals only the flow in the direction and a pressurizing means that pressurizes the pressure in the sliding gap.

In Patent Document 2, for the purpose of performing a leak inspection of a fluid machine capable of leak inspection of a housing due to a change in sealing characteristics, a gas is sealed in the housing to detect the leak amount, and the leak amount is detected based on the leak amount. The process of determining the suitability of the housing, the process of releasing the gas enclosed in the housing to the outside of the housing and reducing the pressure inside the housing to near the atmospheric pressure, and the process of re-encapsulating the gas in the housing to reduce the amount of leakage. It is described that a step of detecting and determining whether or not the housing is possible based on the amount of leakage is provided.

Patent Document 3 includes a group of detectors such as a pressure system and a flow meter, and a group of detectors connected to the detector group for the purpose of diagnosing the cause of deterioration and the degree of deterioration which are the causes of the abnormality and the abnormality of the sealing device. It is described that it has a computer that calculates the sealed flow rate in the assumed state using the calculation model of the sealing device, and detects abnormal signs by comparing the calculated sealing flow rate and the actual sealing flow rate when it is assumed that there is no abnormality. Has been done.

Patent Document 4 describes a capacitive leak sensor, a reference capacitance capacitor connected in parallel to the leak sensor, and a leak for the purpose of predicting in advance the occurrence of a large amount of leakage due to deterioration of the sealing function of the shaft sealing device. A leak detection device for a shaft seal device including a differential amplifier for detecting a capacitance difference between a sensor and a reference capacitance capacitor is described.

Japanese Unexamined Patent Publication No. 2014-9720 JP-A-2007-78630 Japanese Unexamined Patent Publication No. 2001-241550 Japanese Unexamined Patent Publication No. 5-45246

As mentioned above, the contact type rotary seal wears little by little over time, so it is extremely important to understand the wear condition and perform maintenance before chips and cutting water enter from the outside. is there.

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

The seal portion wear estimation device of the present invention is a device for estimating the wear amount of the seal portion of the rotation mechanism portion provided in the machine tool, and the seal portion is from the outside to the inside of the rotation mechanism portion. A contact-type rotary seal for preventing foreign matter from entering is provided, and compressed air is supplied to the inside of the rotary seal, and the pressure is adjusted by a pressure adjusting means for adjusting the pressure of the compressed air and the pressure adjusting means. Based on the air leak detecting means for detecting the air leak of the compressed air, the pressure value adjusted by the pressure adjusting means, and the air leak detected by the air leak detecting means, the amount of wear of the rotary seal is determined. It is provided with an estimation means for estimating.

In one embodiment of the present invention, the rotary seal maintains a contact state when the pressure of the compressed air is equal to or lower than a predetermined pressure in an unworn state, and there is no air leakage from the inside to the outside, and the pressure exceeds the predetermined pressure. In a non-contact state, air leakage of the compressed air occurs.

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

In still another embodiment of the present invention, the pressure adjusting means increases the pressure of the compressed air from the initial pressure to the first pressure, and when the air leak detecting means does not detect an air leak, the pressure is increased from the first pressure. Further increase to a second pressure.

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

Further, the machine tool of the present invention includes the wear amount estimation device for the seal portion according to any one of the above, and an in-flight robot in which the seal portion is provided at a joint.

According to the present invention, the amount of wear of the contact type rotary seal can be estimated. Further, according to the present invention, the maintenance time can be clarified from the estimated wear amount, and the intrusion of chips and cutting water generated during machining can be more reliably prevented.

It is a block diagram of the machine tool of embodiment. It is sectional drawing of the rotary seal of embodiment. It is a wear explanatory drawing of the rotary seal of an embodiment. It is a graph which shows the relationship between the pressure of the wearless rotary seal of embodiment and air leakage. It is a graph which shows the relationship between the pressure of the wear rotation seal of an embodiment, and an air leak. It is a block diagram of the structure of the apparatus of embodiment. It is a circuit diagram of the pressure adjusting means and the air leakage detecting means of embodiment. It is a processing flowchart of an embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a machine tool 10. In the following description, the rotation axis direction of the work spindle device 14 is referred to as a Z axis, the moving direction orthogonal to the Z axis of the tool post 4 is referred to as an X axis, and the Z axis and the direction orthogonal to the X axis are referred to as a 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 turning function of cutting the work with the rotating tool.

The circumference of the machine tool 10 is covered with a cover (not shown). The space partitioned by this cover becomes a processing room in which the work 3 is processed. By providing the cover, chips and the like are prevented from being scattered to the outside. The cover is provided with at least one opening and a door (neither shown) that opens and closes the opening. The operator accesses the inside of the machine tool 10, the work 3, and the like through the opening. During processing, the door provided at the opening is closed. This is to ensure safety and environmental friendliness.

The machine tool 10 includes a work spindle device 14 that holds the work 3 so that it can rotate, and a tool post 4 that holds the tool 100. The work spindle device 14 includes a spindle base installed on the base 22 and a work spindle attached to the headstock. The work spindle is provided with a chuck that holds the work 3 so that it can be gripped and released freely, and the gripped work 3 can be replaced as appropriate. The figure illustrates a configuration in which the work 3 is gripped / released by opening and closing the three claws provided on the chuck, but the number of claws is arbitrary and the two claws provided at positions facing each other are arbitrary. The work 3 may be gripped / released by opening and closing. 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 cutting tool. The tool post 4 and the bite can be linearly moved in the XZ axis direction by a drive mechanism.

At the bottom of the processing chamber, a discharge mechanism is provided for collecting and discharging chips scattered during cutting. Various forms can be considered as the discharge mechanism. For example, the discharge mechanism is composed of 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. The control device in the machine tool 10 is also called a numerical control device (NC), and controls the drive of each part of the machine tool 10 in response to an instruction from an operator. The control device is composed of, for example, one or a plurality of CPUs that perform various operations, a memory that stores various control programs and control parameters, an input / output interface, an input device, and an output device. The input device is, for example, a touch panel or a keyboard, and the output device is a liquid crystal display, an organic EL display, or the like. Both the input device and the output device may be configured by a touch panel. Further, the control device has a communication function and can exchange various data, for example, NC program data, etc. with other devices. The control device may include, for example, a numerical control device that calculates the positions of the tool 100 and the work 3 at any time. The control device may be a single device or may be configured by combining a plurality of arithmetic units.

Further, the machine tool 10 of the present embodiment includes an in-flight robot 20. The in-flight robot 20 includes joints, nodes, and a hand 20d. In the present embodiment, a robot arranged at a predetermined position in the processing chamber is referred to as an in-flight robot. The predetermined position does not necessarily mean a fixed position, and even if it is arranged at a certain position in the initial state, the concept includes a position that can move to a desired position during machining of the work or the like. By driving and controlling the in-flight robot 20, it is possible to attach / detach tools and workpieces 3, clean the inside of the in-flight, tools and workpieces 3, prevent chips from wrapping around, and prevent chattering of the workpieces 3.

The rotation mechanism portion of the in-flight robot 20, for example, a joint, is provided with a seal portion for preventing the intrusion of chips and cutting water from the outside, and for the seal portion, for example, a contact type rotary seal is used.

FIG. 2 is a cross-sectional view showing an example of a contact-type rotary seal used for a joint of the in-flight robot 20. A contact-type rotary seal 40 is provided between the rotary shaft 30 and the fixed portion 32. Specifically, a groove 34 is formed on the facing surface of the rotating shaft 30 of the fixing portion 32, and a rotating seal 40 having a U-shaped or U-shaped cross section is arranged in the groove 34. In the rotary seal 40, the two seal portions of the rotary side seal portion 42 and the fixed side seal portion 44 extend in a U shape or a U shape so that the outer side is the opening side of the U shape or the U shape. It has a cross-sectional shape, and has a contact portion 46 projecting toward the rotating shaft 30 on the opposite surface of 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 rotation side seal portion 42 toward the rotation shaft 30. Further, the rotary side seal portion 42 and the fixed side seal portion 44 are urged to the fixed portion 32 side and the rotary shaft 30 side, respectively, by an elastic member or the like arranged along the bent inner surface of the rotary seal 40. That is, the rotating side seal portion 42 is pressed against the rotating shaft 30 side by the elastic member, and the fixed side sealing portion 44 is pressed against the fixed portion 32 side by the elastic member. In the figure, the urging by the elastic member is shown as a spring, but it may be composed of a spring member arranged inside the U-shape or the U-shape.

Compressed air is further supplied to the inside of the joint sealed by the rotary seal 40 via an air path (not shown), and air purging is performed from the inside. This air purge is usually performed at a pressure slightly higher than the atmospheric pressure (hereinafter, this pressure is referred to as P0). The air purge prevents the intrusion of foreign matter from the outside, that is, foreign matter such as chips and cutting water.

In the normal state, the rotary side seal portion 42 and the fixed side seal portion 44 of the rotary seal 40 are urged to the rotary shaft side and the fixed portion side by elastic members, respectively, so that the contact state is maintained even by air purging with compressed air and compression is performed. 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, and the tapered contact portion. The 46 is separated from the rotating shaft 30 to be in a non-contact state, and a gap is created. Then, the compressed air 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, so that air leakage does not occur unless the pressure of the compressed air is a sufficiently high pressure value corresponding to the contact surface pressure. Does not occur.

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

FIG. 3 schematically shows the state of wear of the contact portion 46. FIG. 3A shows a rotary seal 40 in an unworn state, and FIG. 3B shows a partially enlarged cross-sectional view of the contact portion 46. The tapered contact portion 46 is not worn and the contact surface pressure is relatively large.

FIG. 3C shows a partially enlarged cross-sectional view of the contact portion 46 worn from the non-wear state. The contact portion of the tapered contact portion 46 is worn, and the contact surface pressure becomes relatively smaller than in the unworn state. FIG. 3D shows a partially enlarged cross-sectional view of the contact portion 46 that has been 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. 3C.

As described above, if 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 the unworn state, no air leakage occurs, and even if an air leak occurs when the pressure of the compressed air is increased to P1, the wear of the contact portion 46 progresses. , Air leakage occurs at a pressure lower than the pressure P1 at which air leakage occurs in the unweared state. Considering that the contact surface pressure of the contact portion 46 decreases as the wear progresses, there is a certain correlation between the amount of wear and the pressure at which air leakage occurs, and by using this correlation, air leakage occurs. The amount of wear of the contact portion 46, that is, the amount of wear of the rotary seal 40 can be estimated from the pressure.

FIG. 4 schematically shows the relationship between the pressure of compressed air and air leakage when the rotary seal 40 is in an unwear state. Air leakage does not occur at the pressure P0 of the air purge, 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 the pressure of compressed air and air leakage in a state where the rotary seal 40 is worn and deteriorated. When the rotary seal 40 is worn, the graph showing the relationship between pressure and air leakage shifts to the left side in the figure, and air leakage occurs at a lower pressure. Specifically, when the pressure is increased from P0, air leakage occurs at the 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. When the rotary seal 40 is further worn, the graph shifts further to the left as shown in the figure, and air leakage occurs even at the pressure P0. This state means that air leakage occurs even when the compressed air is purged, and it means that the function of preventing foreign matter from entering cannot be exhibited. In the figure, the slope of the graph is the same for convenience, but the slope of the graph may change depending on the wear.

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

FIG. 6 shows a block diagram of the wear amount estimation device according to the present embodiment. The wear amount estimation device includes a pressure adjusting means 50, an air leak detecting means 52, a wear amount estimating means 54, and a storage means 56.

The pressure adjusting means 50 adjusts the pressure of the compressed air for purging the air of the rotary seal 40 by increasing or decreasing. The pressure adjusting means 50 outputs the adjusted pressure value to the wear amount estimating means 54. The pressure adjusting means 50 includes, for example, a plurality of pressure paths including a plurality of solenoids and a plurality of regulators, and the pressure is changed in a plurality of stages by sequentially switching the plurality of pressure paths. The pressure adjusting means 50 sequentially increases the pressure from the pressure P0 of the air purge.

The air leak detecting means 52 detects an air leak in the rotary seal 40. The air leak detecting means 52 outputs the presence or absence of an air leak to the wear amount estimating means 54. The air leak detecting means 52 includes, for example, a differential pressure gauge sandwiching a diaphragm, and if the differential pressure ΔP is detected, it detects an air flow, that is, there is an air leak.

The storage means 56 stores in advance the correspondence between the pressure value and the air leak as a table 58 by calculation, experiment, or the like. The graph shown in FIG. 5 is an example of the table 58 stored in the storage means 56. The table 58 defines the correspondence between the pressure value of the compressed air and the amount of air leakage for each amount of wear. The amount of air leakage = 0 means that there is no air leakage. The table 58 may specify the correspondence between the pressure value of air leakage and the amount of wear. For example
Air leakage pressure PL1 → wear amount f1
Air leakage pressure PL2 → wear amount f2
Air leakage pressure PL3 → wear amount f3
・ ・ ・
It is like.

The wear amount estimating means 54 estimates the wear amount of the rotary seal 40 based on the pressure value from the pressure adjusting means 50 and the detection result of the air leak from the air leak detecting means 52. When the detection result output from the air leak detecting means 52 is no air leak, the wear amount estimating means 54 outputs a control signal instructing the pressure adjusting means 50 to further increase the pressure. The pressure adjusting means 50 increases the pressure in response to a command from the wear amount estimating means 54. On the other hand, when the detection result output from the air leak detecting means 52 is an air leak, the wear amount estimating means 54 stores the table 58 stored in the storage means 56 based on the pressure value output from the pressure adjusting means 50. The amount of wear corresponding to the pressure is estimated by reference. The wear amount estimating means 54 displays the estimated wear amount on the output device of the machine tool and outputs it.

Specifically, the wear amount estimation means 54 and the storage means 56 are composed of a CPU and a memory. The wear amount estimation means 54 and the storage means 56 may be composed of 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 estimation means 54, and the wear amount estimation means 54 of the control device. The memory functions as the storage means 56. Further, the wear amount estimating 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. For example, the absolute value of the estimated wear amount, for example, the wear amount. It may be output as = 1 mm or the like, and the estimated amount of wear may be relatively output as, for example, wear amount = small, wear amount = medium, or wear amount = large. Further, when the wear amount exceeds a certain threshold value, a message to that effect that the rotary seal 40 needs to be replaced may be output together with the wear amount. In short, the maintenance time based on the wear amount may be output as a message together with the wear amount.

FIG. 7 shows a specific example of the pressure adjusting means 50 and the air leak detecting means 52.

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

The filter 510 filters the compressed air from the compressor and supplies it to the downstream side.

The three solenoids 520, 530, and 540 are connected to each other in parallel with respect to the filter 510 on the downstream side of the filter 510. A regulator 521 is connected to the downstream side of the solenoid 520 to reduce the pressure of the compressed air to the 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 to the downstream side of the solenoid 530 to reduce the pressure of the compressed air to a 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 to the downstream side 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.

The solenoids 520, 530, and 540 connected in parallel to the filter 510 are sequentially ON / OFF controlled by a control signal from the wear amount estimation means 54. That is, first, the solenoid 520 is ON-controlled, and the solenoid 530 and the solenoid 540 are OFF-controlled. As a result, the compressed air from the filter 510 is decompressed to the first pressure by the regulator 521 and output. Next, the solenoid 530 is ON-controlled and the solenoid 520 and the solenoid 540 are OFF-controlled. As a result, the compressed air from the filter 510 is decompressed to the second pressure by the regulator 531 and output. Next, the solenoid 540 is ON-controlled and the solenoid 520 and the solenoid 530 are OFF-controlled. As a result, the compressed air from the filter 510 is decompressed to the third pressure by the regulator 541 and output. When the first pressure <second pressure <third pressure, the pressure of the compressed air is gradually increased by sequentially turning on the solenoids 520, 530, and 540. When the first pressure is the air purge pressure P0, the solenoid 520 is ON-controlled and the solenoid 530 and the solenoid 540 are OFF-controlled to air-purge the rotary seal 40 from the inside.

A rotation mechanism unit is connected to the downstream side of the differential pressure gauge 550 sandwiching the diaphragm, and a solenoid 560 is connected in parallel. The downstream side of the solenoid 560 is connected to the atmosphere side via a diaphragm 570. The solenoid 560 functions as a decompression valve.

The differential pressure gauge 550 as the air leak detecting means 52 measures the differential pressure ΔP on the upstream side and the downstream side of the diaphragm. When there is no air leak, the differential pressure ΔP = 0 because there is no air flow, but when an air leak occurs, the differential pressure ΔP is detected because an air flow occurs. That is, ΔP = 0 corresponds to no air leakage, and ΔP ≠ 0 corresponds to the presence of air leakage. The differential pressure gauge 550 outputs the detected differential pressure ΔP to the wear amount estimating means 54 as an air leak detection result.

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

First, the wear amount estimation means 54 outputs control signals to SOL1, SOL2, and SOL3, controls SOL1 ON, and controls SOL2 and SOL3 OFF (S101). Further, the wear amount estimation means 54 outputs a control signal to the SOL 4 and controls the SOL 4 ON (S102). After ON control of SOL4, the state shifts to the standby state for a predetermined short time (S103), and when a predetermined short time elapses, SOL4 is OFF controlled to end decompression (S104), and then only for a predetermined long time. Stand by (S105). Specifically, the short-time and long-time standby times are stored in the storage means 56 as control parameters.

Since SOL1 is ON-controlled in this long-time standby state, a first pressure is applied to the inside of the rotary seal 40, and the differential pressure ΔP is measured by the differential pressure gauge 550. 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 = 0 (NO in S106), air leakage has already been detected when the first pressure is applied. Therefore, the wear amount estimating means 54 refers to the table 58 and the rotary seal 40. Amount of wear = extra large, that is, it is determined that the wear has progressed considerably (S107).

If ΔP = 0 (YES in S106), the wear amount estimation means 54 determines that there is no air leakage, outputs a control signal to SOL1, SOL2, and SOL3 again, controls SOL1 to OFF, and controls SOL2 to ON. Then, SOL3 is turned off (S108). The SOL4 remains OFF control. After that, like S105, it waits for a predetermined long time (S109).

Since SOL2 is ON-controlled in this long standby state, a second pressure is applied to the inside of the rotary seal 40, and the differential pressure ΔP is measured by the differential pressure gauge 550. 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 = 0 (NO in S110), no air leak is detected at the first pressure, and an air leak is detected when the second pressure is applied. Therefore, the wear amount estimating means 54 , It is determined that the amount of wear of the rotary seal 40 = large, that is, the wear is progressing with reference to the table 58 (S111).

If ΔP = 0 (YES in S110), the wear amount estimation means 54 determines that there is no air leakage, outputs a control signal to SOL1, SOL2, and SOL3 again, controls SOL1 and SOL2 to OFF, and sets SOL3. ON control (S112). SOL4 remains OFF control. After that, like S105 and S109, it waits for a predetermined long time (S113).

Since the SOL3 is ON-controlled in this long standby state, a third pressure is applied to the inside of the rotary seal 40, and the differential pressure ΔP is measured by the differential pressure gauge 550. 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 = 0 (NO in S114), no air leakage is detected at the first and second pressures, and air leakage is detected when the third pressure is applied. Therefore, the amount of wear is estimated. The means 54 determines that the amount of wear of the rotary seal 40 = 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 way, the applied pressure is gradually increased from the first pressure to the second pressure and then to the third pressure, and the amount of wear of the rotary seal 40 is oversized according to the detection result of air leakage at that time. Estimates are made in four stages of large, medium, and small, and the estimation results are output to the output device of the machine tool. As mentioned above, the output form is arbitrary, but for example, when it is estimated that the amount of wear = oversized, "The rotating seal is worn. Replace it immediately."
Etc. is output, and when it is estimated that the amount of wear = large, "The amount of wear of the rotating seal is large. Please replace it."
When it is estimated that the amount of wear = medium, the amount of wear of the rotating seal is medium. It needs to be replaced soon.
Etc. is output, and when it is estimated that the amount of wear = small, "the amount of wear of the rotary seal is small".
Etc. may be output.

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

According to the present embodiment, the inside of the rotary seal 40 is air-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 amount of wear 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 at an arbitrary timing of regular or irregular timing, and chips and cutting water are actually deteriorated due to wear of the rotary seal 40. It is possible to grasp the amount of wear of the rotary seal 40 and clarify the necessary maintenance time before the shavings invade the inside.

Although the embodiments of the present invention have 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 illustrated, but the present invention is not limited to this, and any shape can be used as long as it is a directional rotary seal. Can be used, and a U-packing type or an oil seal type can be used.

Here, "having directional" means preventing foreign matter from entering the inside of the rotation mechanism portion from the outside. Further, the rotary seal 40 may have multiple stages, and may be combined with a labyrinth seal or the like.

Further, in the present embodiment, the applied pressure is adjusted by sequentially ON-controlling SOL1, SOL2, and SOL3, but if necessary, four or more solenoids are connected in parallel and these are sequentially ON-controlled. The applied pressure may be adjusted more finely.

Further, in the present embodiment, the combination of the diaphragm and the differential pressure gauge 550 as shown in FIG. 7 is used as the air leak detecting means 52, but an air flow meter may also be used.

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

Further, in the present 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, but the operator of the machine tool 10 informs the machine tool 10. The wear amount estimation means 54 may execute the process of FIG. 8 in response to the operation instruction of FIG. In this case, for example, when machining the work 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 execute the treatment shown in FIG. 8 prior to machining, and may determine whether or not machining of the work 3 is executed according to the estimation result of the amount of wear.

3 work, 4 tool post, 10 machine tool, 14 work spindle device, 20 in-machine robot, 50 pressure adjusting means, 52 air leak detecting means, 54 wear amount estimating means, 56 storage means, 58 tables, 100 tools.

Claims (6)

It is a device that estimates the amount of wear of the seal part of the rotating mechanism part provided in the 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.
A pressure adjusting means for adjusting the pressure of the compressed air and
An air leak detecting means for detecting an air leak of the compressed air when the pressure is adjusted by the pressure adjusting means, and an air leak detecting means.
An estimation 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.
A wear amount estimation device for a seal portion provided with. When the pressure of the compressed air is less than a predetermined pressure, the rotary seal maintains a contact state and there is no air leakage from the inside to the outside when the pressure of the compressed air is not worn. The wear amount estimation device for a seal portion according to claim 1, wherein air leakage occurs. Further provided with a storage means for storing the correspondence between the amount of wear of the rotary seal and the pressure value at which air leakage occurs.
The wear amount estimation device according to any one of claims 1 and 2, wherein the estimation means estimates the wear amount of the rotary seal based on the correspondence relationship stored in the storage means. The pressure adjusting means increases the pressure of the compressed air from the initial pressure to the first pressure, and when the air leak detecting means does not detect the air leak, the pressure is further increased from the first pressure to the second pressure. The device for estimating the amount of wear of the seal portion according to any one of ~ 3. The wear amount estimation device for a seal portion according to any one of claims 1 to 4, wherein the air leak detecting means is a pressure gauge or a flow meter. The wear amount estimation device for the seal portion according to any one of claims 1 to 5,
An in-flight robot with the seal portion provided at the joint, and
Machine tool equipped with.

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