JP2005249008A - Rotary joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary joint, allowing an arbitrary combination of various additional functional parts related to a sealing part according to a customer's request to be assembled using a common casing, shortening the appointed date of delivery and lowering the manufacturing cost. <P>SOLUTION: This rotary joint RJ has a sealing part 5 communicating a supply hole 3a constituting a rotary shaft side passage with a supply hole 4a constituting a fixed shaft side passage, and various additional functional parts (a leakage detecting function adding module 6, a lubricating function adding module 7 and a breakage detecting function adding module 8a) related to the sealing part 5 are incorporated in the vicinity of the sealing part 5. The various additional functional parts 6, 7, 8 are modularized to be freely removable from predetermined positions (a first circular hole 12, a second circular hole 13) in the casing 1. The various additional functional parts 6, 7, 8a are arbitrarily combined according to purposes and respectively assembled in predetermined positions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rotary joint that is mounted on various machines and is suitable for supplying a liquid such as coolant to a rotating side, and more particularly, to a rotary joint in which various non-functional parts related to the seal portion are incorporated in the vicinity of the seal portion. .

Conventionally, when supplying coolant for cutting to a rotary tool attached to the spindle end of a machine tool, a rotary joint is directly connected to the rear end of the main spindle or the rotor shaft rear end of the direct-coupled spindle motor. The coolant liquid is pumped from the rotary joint through a flow path provided at the shaft center.
Since this type of rotary joint is required to rotate at high speed, a seal ring is installed between the fixed shaft side flow path and the rotary shaft side flow path, respectively, and the fixed part is driven by the hydraulic pressure of the coolant supplied when driving the machine tool. The seal portion is configured by sliding the seal ring on the side in the seal ring direction on the rotating shaft side and bringing them into close contact with each other.

Normally, the sealing surfaces of the seal ring on the fixed side and the seal ring on the rotating shaft side of the seal portion are finished to be smooth on the entire surface so that the coolant liquid flowing in the internal flow path does not leak and completely adhere to each other. ing.
As the rotary joint is operated over a long period of time, the seal surfaces of the fixed seal ring and the rotary shaft seal ring are gradually damaged, resulting in abnormal wear of the seal portion. There are things to do.
Normally, when the seal is damaged, the leaked coolant liquid is discharged from the drain port.However, if the worker immediately notices and shuts down the power supply of the equipment and does not take measures such as stopping the pump, a large amount of coolant liquid is drained. There is a problem in that the coolant cannot be discharged from the opening, and coolant enters the motor from the outer peripheral surface of the main shaft motor arranged on the downstream side, causing coil burnout or bearing breakage due to electric leakage of the main shaft motor, causing large damage. there were.

Therefore, the present inventor has a rotary joint (see Patent Document 1) having a function of detecting leakage of coolant liquid from the seal part, and a rotary joint having a function of detecting abnormal wear or damage of the seal part (patent document 1). The invention of Reference 2) was made.
In addition, in this type of rotary joint, in response to the demand for advanced machining in recent years, when air or the like is pumped instead of the coolant liquid, lubricity is imparted to the seal portion depending on the air or the like. Therefore, the present inventor has invented a rotary joint (see Patent Document 3) that can ensure the lubricity of the seal portion by jetting the lubricating liquid from the outer surface side of the seal portion.

Japanese Patent Application No. 2002-183048 (page 1 of specification, FIG. 1) Japanese Patent Application No. 2002-304607 (Specification page 1, FIG. 1) JP2000-130665 (Specification (page 2), FIG. 4)

  However, the rotary joints of the conventional examples (Patent Documents 1, 2, and 3) have a structure in which each additional function portion is integrally formed with the casing. It is necessary to manufacture a casing having a different specification for each combination of functions, which causes a problem that the delivery time becomes long and the manufacturing cost is high.

  The present invention has been made in order to solve the conventional problems as described above. The purpose of the present invention is to use a common casing, and various additional functional parts related to the seal portion can meet customer demands. It is an object of the present invention to provide a rotary joint that can be assembled in any combination and can reduce delivery time and manufacturing cost.

  In order to solve the above-described problem, the rotary joint according to claim 1 of the present invention has a seal portion that communicates the rotary shaft side flow channel and the fixed shaft side flow channel, and the seal portion is provided near the seal portion. A rotary joint in which various additional functional parts related to the seal portion are incorporated, and the various additional functional parts are modularized in a detachable state at predetermined positions, and the various additional functional parts are used in accordance with applications. Further, the means is characterized in that it can be assembled and installed at a predetermined position in any combination.

  A rotary joint according to a second aspect of the present invention is the rotary joint according to the first aspect, wherein one of the additional functional parts is an abnormality detection means for detecting an abnormality of the seal portion.

  According to a third aspect of the present invention, in the rotary joint according to the second aspect, the abnormality detected by the abnormality detection means is an abnormality due to leakage from the seal portion.

  According to a fourth aspect of the present invention, in the rotary joint according to the third aspect, the rotary joint according to the third aspect has a discharge port that receives the leaked liquid and discharges the leaked liquid when the amount of leakage from the seal portion is within a normal range. The first chamber and the second chamber having a discharge port for receiving the leaked liquid from the first chamber when leaking beyond a normal range and discharging the leaked liquid are provided. .

  According to a fifth aspect of the present invention, in the rotary joint according to the fourth aspect, the leakage from the first chamber is between the partition wall separating the first chamber and the second chamber and the surface of the rotary shaft. It has an annular gap for circulating the liquid to the second chamber, and is provided with air purge means for supplying air toward the annular gap so that the leaked liquid from the seal portion does not flow out from the annular gap. It was a means to do.

  According to a sixth aspect of the present invention, in the rotary joint according to the fourth or fifth aspect, the abnormality detection means is disposed at a position where leakage can be detected when the leakage liquid flows from the first chamber to the second chamber. It was set as the means characterized by.

  A rotary joint according to a seventh aspect is the rotary joint according to the fifth or sixth aspect, wherein the abnormality detection method is configured to introduce a leaked liquid into the abnormality detection means by a force of purge air generated by the air purge means. It was set as the characteristic feature.

  The rotary joint according to an eighth aspect is characterized in that in the rotary joint according to the second aspect, the abnormality detected by the abnormality detection means is an abnormality due to abnormal wear or breakage of the seal portion. .

  The rotary joint according to claim 9 is the rotary joint according to claim 8, wherein the abnormality detecting means detects an abnormality of the seal portion by detecting a vibration of a floating sheet that urges the seal portion to be freely opened and closed. The means is configured to detect wear or breakage.

  The rotary joint according to claim 10 is the rotary joint according to claim 8, wherein the abnormality detection means detects the heat generation of the floating sheet that urges the seal portion to be freely opened and closed, thereby causing the abnormality of the seal portion. The means is configured to detect wear or breakage.

  The rotary joint according to an eleventh aspect is the rotary joint according to the eighth aspect, wherein the abnormality detecting means is transmitted to a floating seat side that urges the seal portion to open and close according to the frictional resistance of the seal portion. By detecting the rotational torque of the rotating shaft, it is configured to detect abnormal wear or breakage of the seal portion.

  A rotary joint according to a twelfth aspect of the present invention is the rotary joint according to the first aspect, wherein one of the additional functional parts is a lubricating means for supplying a lubricating liquid to the seal portion.

  A rotary joint according to a thirteenth aspect is the rotary joint according to any one of the first to twelfth aspects, wherein the rotary shaft is connected to a rotary shaft of a machine tool.

  In the rotary joint according to claim 1, as described above, the various additional functional parts are modularized in a detachable state at predetermined positions, and the various additional functional parts are arbitrarily selected according to the application. It is possible to assemble and install various additional functional parts related to the seal part in any combination according to the customer's request using a common casing by being configured so that it can be assembled and installed at each predetermined position. As a result, it is possible to shorten the delivery time and reduce the manufacturing cost.

In the rotary joint according to the second aspect, as described above, the abnormality of the seal portion is detected by the abnormality detection means. If this abnormality of the seal is continued as it is, it will have an adverse effect on the machine body side, but by using this abnormality detection means, it can be detected at the initial stage of occurrence of the abnormality regardless of manual operation. Thus, the power supply to the fluid pump and the machine main body can be automatically shut down to stop the operation of the machine.
Therefore, it is possible to detect an abnormality of the rotary joint seal portion and to prevent an adverse effect due to the abnormality of the seal portion from spreading to the machine body.

In the rotary joint according to claim 3, if there is an abnormality in the seal portion that communicates the rotary shaft flow path and the fixed side flow path, a large amount of liquid leaks, and if this leaked liquid enters the electric motor or the bearing section, a leakage accident occurs. In order to cause a seizure accident or the like, liquid leakage from the seal portion is constantly monitored by an abnormality detection means.
Therefore, a large amount of liquid leakage from the seal part is automatically detected at the initial stage of occurrence of abnormality without human intervention, the fluid pump and the machine body are turned off, etc., and the rotary joint is stopped to operate. It is possible to prevent the damage from being caused.

In the rotary joint according to the fourth aspect, as described above, when the amount of leakage from the seal portion is within a normal range, the first chamber receives the leaked liquid and discharges it from the discharge port. When the seal part becomes abnormal due to breakage, etc., that is, when the amount of leaked liquid exceeds the normal range, it leaks to the downstream side, and the second chamber receives the leaked liquid and discharges it from the discharge port to the outside. It is possible to prevent the leaked liquid from entering the main shaft side.
Therefore, even when there is an abnormality in the seal portion and the drainage liquid cannot be drained in the first chamber, the second chamber can receive and drain the drainage and reliably prevent damage to downstream equipment. The effect of becoming is obtained.

In the rotary joint according to the fifth aspect, air purging is performed upstream of the annular gap between the first and second chambers between the first chamber and the second chamber. The amount of leaked liquid greatly exceeds the normal range due to breakage of the seal part, and leaks from the first chamber to the second chamber via an annular gap between the partition wall separating the first chamber and the second chamber and the surface of the rotary shaft. However, the air purge performed toward the annular gap prevents entry into the second chamber.
Therefore, even if an abnormal situation occurs in which a liquid leaks from the seal portion of the rotary joint, an effect can be obtained that the leaked liquid can be strictly protected without entering the downstream device.

In the rotary joint according to the sixth aspect, the abnormality detection means immediately detects the leaked liquid from the first chamber to the second chamber.
Therefore, the leaked liquid before entering the second chamber is automatically detected, so that it is possible to prevent the spindle motor and the like from being damaged even if an abnormality occurs in the rotary joint seal portion. The effect is obtained.

  In the rotary joint according to claim 7, since the leakage liquid is introduced into the abnormality detection means by the force of the purge air by the air purge means, the abnormality detection can be performed quickly and reliably, and the introduction port is also set in a narrow place. Therefore, it is possible to select the best place even if it is narrow, and to obtain an effect such that detection with good sensitivity can be performed.

  The rotary joint according to claim 8 is provided with an abnormality detecting means for monitoring the seal portion and detecting an abnormality due to abnormal wear or damage of the seal portion, thereby grasping abnormal wear or breakage of the seal portion from the initial stage. The effect is that it becomes possible to deal with damage before the device is damaged.

  In the rotary joint according to claim 9, when the abnormality detection means detects the vibration of the floating sheet, it is possible to monitor a change in vibration that causes the seal portion to start to be abnormally worn and breakage, and according to the detected vibration. As a result, it is possible to take early measures such as issuing a stepwise warning before the seal portion is broken to prompt the administrator to replace the seal portion.

  In the rotary joint according to claim 10, when the abnormality detection means detects the heat generation of the floating sheet, it is possible to monitor a change in heat generation that causes the seal portion to start abnormal wear and lead to breakage, and according to the detected heat generation. As a result, it is possible to take early measures such as issuing a stepwise warning before the seal portion is broken to prompt the administrator to replace the seal portion.

  In the rotary joint according to claim 11, when the abnormality detection means detects the rotational torque of the rotating shaft transmitted to the floating seat side according to the frictional resistance of the seal portion, the seal portion starts to be abnormally worn and is damaged. Changes in rotational torque can be monitored, and early measures are taken, such as issuing a step-by-step warning and prompting the administrator to replace the seal part before the seal part breaks according to the detected rotational torque. The effect that it will be able to do is acquired.

  The rotary joint according to claim 12 is provided with a lubricating means for supplying a lubricating liquid to the seal portion, thereby ensuring the sealing performance and lubricity of the seal portion even in the case of air having no lubricity. The effect of being able to do it is acquired.

  In the rotary joint according to claim 13, the rotating shaft is connected to the rotating shaft of the machine tool, and when there is an abnormality in the seal part of the rotary joint, the abnormality is detected immediately, and the coolant from the rotary joint is detected. It is possible to prevent damage to important parts such as bearings and spindle motors by taking measures such as issuing an alarm in advance when a leak occurs or before the leak occurs. This function is effective not only when a machine tool is used alone, but also when centrally managing a group of machine tools on a production processing line.

Embodiments of the present invention will be described below with reference to the drawings.
<Example 1>
In Embodiment 1 of the present invention, a case where the rotary joint RJ is mounted on a horizontal main shaft will be described. Of course, this configuration is not limited to the horizontal type, and can be mounted on a vertical main shaft.

  FIG. 1 is a longitudinal sectional view showing a rotary joint RJ according to Embodiment 1 of the present invention. In the figure, 1 is a casing of a spindle motor not shown, 2 is a rotor shaft of a spindle motor not shown, and 3 is a rotating shaft. 4 is a floating sheet, 5 is a seal portion, 6 is a leakage detection function addition module (additional function parts / abnormality detection means), 7 is a lubrication function addition module (additional function parts / lubrication means), and 8a is a damage detection function addition module. (Additional function parts / abnormality detection means) are shown.

  More specifically, the casing 1 of the rotary joint RJ includes a main shaft motor (not shown) on one end side (left side), and the other end side (right side) of the casing 1 has a rotor shaft of the main shaft motor. A shaft hole 11 into which the shaft 2 is rotatably inserted is supported, and a first circular hole 12 having a diameter larger than the shaft hole 11 and concentric with the shaft hole 11 is formed at the end of the shaft hole 11. A second circular hole 13 having a larger diameter and concentric circle than the circular hole 12 is formed.

  The opening of the second circular hole 13 is closed by a lid body 14 that is detachably attached to the opening end surface of the casing 1 with a bolt. A support hole 14a for supporting the shaft portion 41 so as to be slidable in the axial direction is formed, and the support hole 14a is in communication with a connection hole 14b that is connected to a supply portion such as a coolant liquid.

  The floating sheet 4 communicates a fixed shaft side flow path and a rotary shaft side flow path, which will be described later, via a seal portion 5, and the shaft portion 41 is inserted into the support hole 14a so as to be slidable in the axial direction. The space between the inner peripheral surface of the support hole 14a and the outer peripheral surface of the shaft portion 41 is sealed by the seal ring 14c that is supported and provided on the inner peripheral surface of the support hole 14a.

On the other hand, the rotary shaft 3 is screwed to the end of the rotor shaft 2, and is fixed to the end surface of the floating seat 4 and the seal ring 51 (seal portion 5) fixed to the end surface of the rotary shaft 3. The seal ring 52 (seal part 5) faces the substantially circular central part of the second circular hole 13 in the axial direction.
A supply hole 2a that forms a flow path for supplying coolant liquid or the like supplied from the connection hole 14b to a machine tool or the like is provided in the axial center portion of the rotor shaft 2, the rotation shaft 3, and the floating sheet 4. A hole (rotary shaft side flow path) 3a and a supply hole (fixed shaft side flow path) 4a are formed.

  Further, between the flange portion 42 formed on the outer periphery of the end portion of the floating sheet 4 on the seal ring 52 side and the lid body 14, the floating sheet 4 is pressed and urged in a direction in which the seal ring 52 always contacts the seal ring 51. A coil spring 43 is interposed. When the coolant liquid is supplied from the connecting hole 14b, the supply pressure of the coolant liquid is received by the annular end surface of the shaft portion 41 of the floating sheet 4 so that the floating sheet 4 is pressed and slid. By closely contacting the seal ring 51, coolant liquid or the like is supplied to the supply hole 2a of the rotor shaft 2 via the supply holes 4a and 3a communicating with each other. The coil spring 43 is set to a weak biasing force so that there is no gap between the seal rings 51 and 52.

  The leak detection function addition module (additional function component) 6 constitutes an abnormality detection means for detecting an abnormality of the seal portion 5 by detecting an abnormal liquid leak from the seal portion 5, and this leak detection function addition The module 6 is modularized so that it can be detachably assembled to the second circular hole 13 of the casing 1.

  That is, the leakage detection function adding module 6 is formed in an annular partition shape that closes the gap between the second circular hole 13 and the rotary shaft 3 at the bottom of the second circular hole 13. It is positioned and arranged in a state where it abuts and engages with an annular step 15 formed between the bottom of the hole 13, that is, between the first circular hole 12 and the second circular hole 13.

Further, as shown in detail in FIG. 2, the leakage detection function addition module 6 is provided so as to perform air purge toward the annular gap between the rotation shaft 3 and the leakage detection function addition module 6. Two annular grooves 61 and 62 are provided around the inner peripheral surface of the leak detection function addition module 6, and are formed on the upper outer peripheral surface of the leak detection function addition module 6 by the air flow paths 63 and 64, respectively. The air supply port 1 a that opens to the upper part of the casing 1 is communicated with the air through a recess 65.
In the annular grooves 61 and 62, the upstream clearance Sa is made larger than the downstream clearance Sb so that the air purge amount toward the upstream is increased, so that the leaked liquid passes through the annular clearance. (Air purge means).

  Further, a leakage detection groove 66 is provided between the annular grooves 61 and 62, and the detection flow path 1 c extends to the detection opening 1 b formed in the lower part of the casing 1. Reference numeral 67 denotes a detection sensor, which is attached to the detection port 1b via a connector 67a. This connector 67a is directly connected to the detection flow path 1c via a relatively large diameter detection path 67b, and a liquid receiving chamber 67d in which a detection portion 67c composed of a pair of electrodes is disposed, and purge air and leakage from the liquid receiving chamber 67d. A discharge port 67e for discharging the liquid is provided.

  That is, the liquid leakage is introduced into the detection sensor 67 by the force of the purge air supplied from the annular groove 61 while being configured to be able to detect an abnormal liquid leakage when the liquid is about to flow out via the annular gap. It is configured as follows.

  As described above, the leakage detection function addition module 6 is arranged so that the inside of the casing 1 is constituted by the second circular hole 13 between the leakage detection function addition module 6 and the lid body 14, and the seal portion. The first chamber that receives and discharges leaked liquid when the amount of leaked liquid from 5 is within the normal range, and the first chamber that leaks from the annular gap when the amount of leaked liquid greatly exceeds the normal range. It is in a state of being partitioned into a second chamber constituted by the first circular hole 12 that receives and discharges the leaked liquid.

  The lubrication function addition module (additional function component / lubricating means) 7 supplies a lubricating liquid from the outer surface side to the seal portion 5 when supplying a fluid having no lubricity such as air to the machine tool. The lubrication function added module 7 is modularized so that it can be detachably assembled with the second circular hole 13 of the casing 1 to ensure lubricity of the seal portion 5. Has been.

  In other words, the lubrication function added module 7 has the inner peripheral surface of the axial center hole 72 in a state where the outer peripheral portion 71 is in contact with and locked to the end surface of the leak detection function added module 6 in the second circular hole 13. Are positioned and arranged in a state of being arranged in proximity to the outer peripheral portion of the seal portion 5.

  The lubrication function addition module 7 is provided with an ejection port 73 for injecting a lubricating liquid toward the seal portion 5 at the upper part of the inner peripheral surface of the shaft center hole 72. 74, the lubricating function supply module 7 communicates with a lubricating liquid supply port 1 d opened at the top of the casing 1 through an annular groove 75 provided around the outer peripheral surface of the module 7.

  The breakage detection function addition module (additional function component / abnormality detection means) 8 includes a rotary shaft 3 that is transmitted to the side of the floating sheet 4 that urges the seal portion 5 to open and close according to the frictional resistance of the seal portion 5. This is installed in order to detect abnormal wear or breakage of the seal portion 5 by detecting rotational torque, and this breakage detection function addition module 8a is attached to and detached from the second circular hole 13 of the casing 1. It is modularized so that it can be freely assembled and installed.

  That is, the breakage detection function addition module 8a is formed between the outer peripheral end face of the lubrication function addition module 7 in the second circular hole 13 and the outer peripheral end face of the insertion portion of the lid 14 into the second circular hole 13. It is positioned and arranged so as to surround the outer periphery of the floating sheet 4 while being sandwiched therebetween.

  The breakage detection function addition module 8a has a protrusion 42a formed on the flange portion 42 of the floating sheet 4. When the breakage detection function addition module 8a is not installed, the breakage detection function addition module 8a The pin 44 attached and fixed to the portion 42a is inserted and locked so as to be slidable in the axial direction with respect to the sliding locking hole 14d formed in the lid body 14, whereby the floating sheet 4 is prevented from rotating. Yes.

As shown in detail in FIG. 3 (a) (longitudinal sectional view), the damage detection function addition module 8a is applied to the inner peripheral surface of the damage detection function addition module 8a, respectively, on the left and right end surfaces of the protrusion 42a. The shear pins 81 and 82 that are in contact with each other are fixed, and further, stopper pins 83 and 84 that are insulated from the damage detection function addition module 8a and the floating sheet 4 are fixed to the inner peripheral surface of the damage detection function addition module 8a. .
The floating sheet 4 and the stopper pins 83 and 84 are connected to the detection circuit 85, respectively. Reference numeral 86 denotes a power source such as a battery and an 87 alarm.

  The shear pins 81 and 82 are configured to be broken when a torque of a predetermined value or more is applied. The shear pins 81 and 82 serve to prevent the floating sheet 4 from rotating when the seal portion 5 is normal. In the rotational direction on the shaft 3 side, for example, in the direction of the arrow in the figure, the shear pin 81 abuts against the protrusion 42 a of the flange portion 42 to receive the rotational torque transmitted from the rotational shaft 3 side to the floating sheet 4.

  When the seal surfaces of both the seal rings 51 and 52 are uneven, and the seal portion 5 is heated and abnormally worn and the friction of the seal portion 5 increases, the transmission torque transmitted from the rotating shaft 3 side to the floating sheet 4 Will increase. When the transmission torque reaches a predetermined value or more, as shown in FIG. 3B, the shear pin 81 is broken, the floating sheet 4 is rotated in the direction of the arrow, and the protrusion 42a comes into contact with the stopper pin 83.

  At this time, one circuit is formed between the detection circuit 85, the power source 86, and the floating sheet 4, and the detection circuit 85 detects the current of the power source 86, and the alarm device 87 performs step-by-step alarms and power-off of various devices. Is supposed to do.

  In addition, the shear pin 82 and the stopper pin 84 are provided in preparation for the case where the rotation direction on the rotary shaft 3 side is the opposite direction to the arrow in the figure. Omitted.

  Drain ports 1e, 1f, and 1g are formed at the bottoms of the first circular hole 12 and the second circular hole 13 in the casing 1, respectively, and at the bottoms of the lubrication function adding module 7 and the damage detection function adding module 8. Communication holes 76 and 88 communicating with the drain ports 1f and 1g are formed, respectively.

Next, the operation and effect of the present embodiment will be described.
[Actions and effects of modularizing additional function parts]
In the rotary joint RJ of the first embodiment, as described above, various additional function components (leakage detection function addition module 6, lubrication function addition module 7, and breakage detection function addition module 8a) are respectively in predetermined positions. It is modularized in a detachable state, and the various additional functional parts can be assembled and installed at predetermined positions in any combination according to their use, thereby using a common casing 1 and sealing Various additional functional parts related to the unit 5 can be assembled and installed in any combination according to the customer's request.
Accordingly, it is possible to shorten the delivery time and reduce the manufacturing cost.

  Of the various additional functional parts, when the leakage detection function additional module 6 or the lubrication function additional module 7 is not required, a spacer having the same thickness is simply incorporated at each assembly position in the second circular hole 13. Good. When the breakage detection function addition module 8a is not necessary, a spacer having the same thickness is incorporated, and a pin 44 attached and fixed to the protrusion 42a as shown by a two-dot chain line is formed on the lid 14. The floating sheet 4 is prevented from rotating by being inserted and locked to the dynamic locking hole 14d so as to be slidable in the axial direction.

[Operation and effect of leak detection function addition module 6]
The rotary joint RJ configured as described above first slides the floating sheet 4 to the downstream side by the hydraulic pressure of the coolant or the like supplied from the connection hole 14b before starting the spindle motor. The seal ring 52 is brought into close contact with the seal ring 51 at the tip of the rotary shaft 3. In this state, the connecting hole 14b is communicated with the supply port 2a of the rotor shaft 2 via the supply hole 4a, the seal portion 5, and the supply hole 3a, and coolant liquid or the like is supplied to the tool tip with pressure. .

  When purge air is supplied from the air supply port 1a of the casing 1, the purge air is branched into two air flow paths 63 and 64 by the recess 65 and supplied to the annular grooves 61 and 62, respectively. Of these, in the upstream annular groove 62, the outer peripheral surface of the rotary shaft 3 is air purged from the upstream clearance Sa toward the second circular hole 13, and in the downstream clearance Sb, air purge is performed into the detection groove 66.

  In this case, since the upstream clearance Sa> the downstream clearance Sb, the air pressure in the annular grooves 61 and 62 and the detection groove 66 is higher in the annular groove 61 in the downstream arrangement than in the annular groove 62 in the upstream arrangement. Thus, the air flows from the downstream side to the upstream side and the detection groove 66 side. The purge air is discharged to the outside through the drain ports 1e and 1f on the second circular hole 13 side, and from the discharge port 67e to the outside in the liquid receiving chamber 67d through the detection channel 1c and the detection channel 67b in the detection groove 66. To be discharged.

  In this state, the spindle motor is started and the machine tool is in an operating state. During this operation, when the seal portion 5 is in an abnormal state, for example, when a large amount of coolant liquid leaks due to the seal ring 51 or 52 being damaged, Since the part 5 is in the second circular hole 13, the leaked coolant liquid or the like is discharged to the outside of the casing 1 through the drain ports 1e and 1f.

  However, the leakage amount exceeds the drainage amount from the drain ports 1e and 1f, and the leakage coolant liquid or the like fills the second circular hole 13, and reaches the annular gap portion between the leakage detection function addition module 6 and the rotary shaft 3. In this case, the purge air supplied from the annular groove 62 toward the annular gap is purged from the upstream gap Sa toward the second circular hole 13 to prevent the coolant liquid from entering. When the pressure of the coolant liquid or the like wins and enters the gap Sa, the coolant liquid or the like that reaches the downstream detection groove 66 from the upstream gap Sa immediately rides on the purge air supplied from the downstream annular groove 61. It is sent from the detection groove 66 to the liquid receiving chamber 67d via the detection flow path 1c.

  In this liquid receiving chamber 67d, when the leakage coolant liquid or the like shorts the detection portion 67c formed of a pair of electrodes, the circuit from the detection circuit 85 is closed and an abnormal leakage is output. In response to this signal, the detection circuit 85 immediately shuts off the coolant pump and stops the supply of coolant liquid or the like. Also, the power supply of the spindle motor is shut off and only air purge is performed.

  As described above, the leakage coolant liquid or the like that has entered the annular gap is higher in the annular groove 61 in the downstream side than the annular groove 62 in the upstream side in the air pressure in the annular grooves 61 and 62 and the detection groove 66. Therefore, it is less likely to blow back to the upstream side and enter the downstream side.

  As described above, the leak detection function addition module 6 prevents the intrusion of leakage coolant or the like from the first chamber (second circular hole 13) to the second chamber (first circular hole 12) by air purge. can do. Further, since the downstream air purge is set to a pressure higher than that of the upstream air purge, it is possible to prevent the leakage coolant liquid or the like from being pushed downstream by the upstream air purge.

  In the unlikely event that the leaked coolant liquid enters the gap Sa, it reaches the liquid receiving chamber 67d on the purge air flowing into the detection flow path 1c from the detection groove 66 and can be immediately detected by the detection sensor 67. It is possible to prevent leakage to the downstream side and to prevent a large damage from occurring.

Since the detection sensor 67 detects the portion where the downstream leakage of the coolant liquid or the like has occurred in the casing 1, it is possible to perform a damage prevention process immediately after the leakage of the coolant liquid or the like due to an abnormality in the seal portion 5.
In addition, the structure is extremely simple and reasonable, and the overall configuration can be made compact, and effects such as easy installation in a limited range of a target machine such as a machine tool can be obtained.

[Operation and effect of the damage detection function addition module 8]
In the breakage detection function addition module 8, the shear pins 81 and 82 serve to prevent the floating sheet 4 from rotating when the seal portion 5 is normal, and of the shear pins 81 and 82, the rotation direction on the rotary shaft 3 side, for example, In the direction of the arrow shown in FIG. 3A, the shear pin 81 abuts against the protrusion 42a of the flange portion 42 to receive the rotational torque transmitted to the floating sheet 4 from the rotary shaft 3 side.

  When the seal surfaces of both the seal rings 51 and 52 are uneven, and the seal portion 5 is heated and abnormally worn and the friction of the seal portion 5 increases, the transmission torque transmitted from the rotating shaft 3 side to the floating sheet 4 3 and increases to a predetermined value or more, as shown in FIG. 3B, the shear pin 81 is broken, the floating sheet 4 rotates in the direction of the arrow, and the protrusion 42a contacts the stopper pin 83, thereby detecting The circuit 85 detects this, and the alarm device 87 performs stepwise alarms and power-off of various devices.

  Therefore, when the seal part 5 is abnormally worn and the coefficient of friction becomes large, the abnormality is detected, and before the seal part 5 breaks, a stepwise alarm is issued to replace the seal part 5 to the administrator. It is possible to obtain an effect of prompting or taking measures such as power-off of various devices.

  Next, another embodiment of the present invention will be described. The other embodiment shows another example of the damage detection function addition module 8a. In the description of the other embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted, and only differences will be described.

<Example 2>
The breakage detection function addition module 8b of the second embodiment is configured to detect abnormal wear or breakage of the seal portion 5 by detecting the vibration of the floating sheet 4.

  That is, as shown in the cross-sectional view of the main part of FIG. 4, the damage detection function addition module 8b uses an acceleration sensor S1 as vibration detection means, and an annular body provided with the acceleration sensor S1 is connected to a seal ring 52. It is modularized so that it can be detachably assembled and mounted in a state where it is mounted on the outer periphery of the front end portion of the fixed floating sheet 4 and abutted and locked to the flange portion 42.

  The detection signal from the acceleration sensor S1 is connected to a detection circuit 85 provided outside the casing 1, and the vibration value detected by the detection circuit 85 is compared with the vibration value at the normal time, and exceeds this value. In such a case, an alarm signal is transmitted to the alarm device 87 to generate an alarm, or to power off various devices.

  Therefore, in the breakage detection function addition module 8b of the second embodiment, the acceleration sensor S1 detects the vibration of the floating sheet 4, thereby detecting an abnormality from the initial stage where the seal portion 5 is abnormally worn, Before the unit 5 is damaged, a stepwise alarm is issued to prompt the administrator to replace the seal unit 5 or to take measures such as powering off various devices.

<Example 3>
The breakage detection function addition module 8c of the third embodiment is configured to detect abnormal wear or breakage of the seal portion 5 by detecting heat generation of the seal portion 5.

  That is, in the breakage detection function adding module 8c, as shown in the cross-sectional view of the main part in FIG. 5, the temperature sensor S2 is used as the heat generation detection means, and the annular body provided with the temperature sensor S2 It is modularized so that it can be detachably assembled and installed in close contact with the outer periphery of the front end of the fixed floating sheet 4.

  The temperature sensor S2 constantly detects the heat (temperature) transmitted from the seal portion 5 to the floating sheet 4 and transmits it to the detection circuit 85, and the detection circuit 85 gives a stepwise alarm according to the detection value of the temperature sensor S2. Or power off various devices.

  Therefore, in the breakage detection function addition module 8c of the third embodiment, the temperature sensor S2 detects the heat generation of the seal portion 5, thereby detecting an abnormality from the initial stage where the seal portion 5 is abnormally worn, Before the unit 5 is damaged, a stepwise alarm is issued to prompt the administrator to replace the seal unit 5 or to take measures such as powering off various devices.

The embodiment of the present invention has been described above, but the specific configuration of the present invention is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like without departing from the gist of the present invention. include.
For example, in the first embodiment, the detection of leakage (leakage coolant) is described as an electrode type, but the type of the detection sensor is arbitrary, and various methods such as a method of optically detecting a droplet can be employed.

Further, a piezoelectric element may be provided instead of the shear pins 81 and 82 described in the first embodiment, and a current proportional to the load received by these may be detected to monitor the abnormality of the seal portion 5.
Furthermore, it is naturally conceivable that the detection circuit 85 is connected to a personal computer to monitor the detection result, and that the abnormal state of the seal portion 5 and the coping method are communicated by a voice message instead of an alarm.

  In addition to the first to third embodiments, the breakage detection function addition module is composed of an additional body that can be detachably assembled to the floating sheet 4, and a magnet and a coil that circulates in a non-contact state with the magnet. It may be provided with a vibration detection sensor.

  In addition to the case where the vibration detecting means is provided on the floating sheet 4, the vibration detecting means is provided in an annular body that can be removably assembled in the second circular hole 13 in the casing 1, so that the vibration of the floating sheet 4 can be prevented. You may make it detect with the non-contact sensor detected in a contact state.

1 is a longitudinal sectional view showing a rotary joint of Example 1. FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing an air purge part in the rotary joint of Example 1. It is a longitudinal cross-sectional view which shows the destruction detection function addition module 8a part in the rotary joint of Example 1. FIG. It is principal part sectional drawing which shows the destruction detection function addition module 8b part of Example 2. FIG. It is principal part sectional drawing which shows the destruction detection function addition module 8c part of Example 3. FIG.

Explanation of symbols

RJ Rotary joint S1 Acceleration sensor S2 Temperature sensor Sa Upstream clearance of air purge section Sb Downstream clearance of air purge section 1 Casing 1a Air supply port 1b Detection port 1c Detection channel 1d Lubricating fluid supply port 1e Drain port 1f Drain port 1g Drain Port 2 Rotor shaft of spindle motor 2a Supply hole 3 Rotating shaft 3a Supply hole (Rotating shaft side flow path)
4 Floating sheet 4a Supply hole (fixed shaft side flow path)
5 Seal section 6 Leakage detection function addition module (Additional function parts / abnormality detection means)
7 Lubricating function addition module (additional function parts / lubricating means)
8a Damage detection function addition module (additional function parts / abnormality detection means)
8b Damage detection function addition module (additional function parts / abnormality detection means)
8c Damage detection function addition module (additional function parts / abnormality detection means)
11 Shaft hole 12 First circular hole (second chamber)
13 Second circular hole (first chamber)
14 Lid 14a Support hole 14b Connection hole 14c Seal ring 14d Sliding engagement hole 15 Annular step part 41 Shaft part 42 Flange part 42a Projection part 43 Coil spring 44 Pin 51 Seal ring (seal part)
52 Seal ring (seal part)
61 downstream annular groove 62 upstream annular groove 63 air flow path 64 air flow path 65 recess 66 detection groove 67 detection sensor 67a connector 67b detection path 67c detection part 67d liquid receiving chamber 67e discharge port 71 outer peripheral part 72 axial hole 73 jet Outlet 74 Lubricating liquid flow path 75 Annular groove 76 Communication hole 81 Shear pin 82 Shear pin 83 Stopper pin 84 Stopper pin 85 Detection circuit 86 Power supply 87 Alarm 88 Communication hole

Claims (13)

A rotary joint having a seal portion for communicating the rotary shaft side flow path and the fixed shaft side flow path, and various additional functional parts related to the seal portion are incorporated in the vicinity of the seal portion,
The various additional function parts are modularized in a detachable state at predetermined positions, and the various additional function parts can be assembled and installed at predetermined positions in any combination according to the application. A rotary joint characterized by   2. The rotary joint according to claim 1, wherein one of the additional functional parts is an abnormality detection unit that detects an abnormality of the seal portion. 3.   The rotary joint according to claim 2, wherein the abnormality detected by the abnormality detection means is an abnormality due to leakage from the seal portion.   The rotary joint according to claim 3, wherein a first chamber having a discharge port for receiving the leaked liquid and discharging the leaked liquid when the leak amount from the seal portion is within a normal range, and exceeding the normal range. And a second chamber having a discharge port for receiving the leaked liquid from the first chamber and discharging the leaked liquid.   5. The rotary joint according to claim 4, wherein an annular gap is provided between the partition wall separating the first chamber and the second chamber and the surface of the rotary shaft to allow leakage liquid from the first chamber to flow into the second chamber. The rotary joint is provided with air purge means for supplying air toward the annular gap so that the leaked liquid from the seal portion does not flow out from the annular gap.   6. The rotary joint according to claim 4, wherein the abnormality detection means is disposed at a position where leakage can be detected when leaked liquid flows from the first chamber to the second chamber.   7. The rotary joint according to claim 5, wherein the abnormality detection method is configured to introduce a leaked liquid into the abnormality detection means by a force of purge air by the air purge means.   The rotary joint according to claim 2, wherein the abnormality detected by the abnormality detection means is an abnormality due to abnormal wear or damage of the seal portion.   9. The rotary joint according to claim 8, wherein the abnormality detection means is configured to detect abnormal wear or damage of the seal portion by detecting vibration of a floating sheet that urges the seal portion so as to be freely opened and closed. A rotary joint characterized by   9. The rotary joint according to claim 8, wherein the abnormality detection means is configured to detect abnormal wear or breakage of the seal portion by detecting heat generation of a floating sheet that urges the seal portion to open and close. A rotary joint characterized by   9. The rotary joint according to claim 8, wherein the abnormality detection means detects a rotational torque of the rotating shaft transmitted to a floating seat side that urges the seal portion to open and close according to a frictional resistance of the seal portion. Accordingly, the rotary joint is configured to detect abnormal wear or breakage of the seal portion.   2. The rotary joint according to claim 1, wherein one of the additional functional parts is a lubricating means for supplying a lubricating liquid to the seal portion. 3.   The rotary joint according to any one of claims 1 to 12, wherein the rotary shaft is connected to a rotary shaft of a machine tool.

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