JP4093403B2 - Rotary joint - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
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 that detects a seal abnormality and protects a directly connected main shaft motor or the like.
[0002]
[Prior art]
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 part and the rotating shaft, and the seal ring on the fixed part side is moved to the rotating shaft side by the hydraulic pressure of the coolant supplied when driving the machine tool. It seals by making it slide to the seal ring direction of this, and adhering both.
In such a seal structure, a small amount of coolant may flow out by loading or unloading the coolant pressure even under normal use conditions. A drain port is provided to discharge the coolant. This drain port is provided with a sufficiently large diameter so that even if the seal breaks during operation and a large amount of coolant flows out, the operator knows the abnormality of the seal from the drain state from this drain port. The equipment is shut down to protect the equipment.
[0003]
[Problems to be solved by the invention]
As described above, if the seal is damaged, a large amount of coolant leaks and 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 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. It was.
In addition, there is an increasing demand for automatic detection of abnormalities that have been performed by visual inspection of workers until now, and for centrally managing abnormalities in a machine group on a production processing line in one centralized location.
[0004]
The present invention has been made in order to solve the above-described conventional problems. The object of the present invention is to detach the seal rings with liquid pressure, for example, so that the rotation-side flow path and the fixed-side flow path are separated. Machine parts in the production processing line are automatically detected by detecting abnormalities in the seals that supply coolant and other liquids to the main parts of the equipment by communicating with them and automatically protecting the spindle motor. An object of the present invention is to provide a rotary joint having a function capable of centrally managing group abnormalities.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the rotary joint according to claim 1 of the present invention has a seal portion that communicates the rotation shaft flow path of the rotation shaft and the fixed-side flow path, and detects an abnormality of the seal section. A first chamber that receives leakage when the leakage from the seal portion is within a normal range; and a first chamber that receives the leaked liquid when the leak amount from the seal portion is within a normal range. Is provided with a second chamber that is partitioned by a partition and receives leaked liquid from the first chamber when leaking greatly beyond the normal range, and two annular grooves are provided around the through hole of the partition. Each of which is communicated with an air supply port by an air flow path, and a detection groove for leakage coolant is provided between two annular grooves in the through-hole, and through a detection flow path extending from the detection groove. When leaked from the first chamber to the second chamber, the leaked liquid And a means, characterized in that knowledge detecting means is disposed.
[0006]
In the rotary joint according to claim 2, in the rotary joint according to claim 1, there is a gap between the partition wall separating the first chamber and the second chamber and the surface of the rotary shaft, The upstream gap which is the first chamber side is made larger than the downstream gap which is the second chamber side, and the air purge amount toward the upstream side which is the first chamber side is increased. It was a means to do.
[0007]
According to a third aspect of the present invention, in the rotary joint according to the first or second aspect of the present invention, the rotary joint having a rotating shaft is a machine tool.
[0008]
In the rotary joint according to claim 4, in the rotary joint according to any one of claims 1 to 3, an air vent opening for allowing purge air to escape from the liquid receiving portion is opened, and the force of purge air is used. The means is characterized in that the leakage liquid is introduced into the detection means.
[0012]
Operation and effect of the invention
In the rotary joint according to the first aspect, the abnormality of the seal portion is detected by the detecting means. If this abnormality of the seal part is continued as it is, it will adversely affect the machine body side, but by using the detection means, it can be detected at the initial stage of occurrence of the abnormality regardless of manual operation. The power supply to the pump and the machine body can be automatically turned off to stop the operation of the machine.
Therefore, in the rotary joint according to the first aspect, it is possible to detect the abnormality of the rotary joint seal portion and to prevent the adverse effect due to the seal portion abnormality from spreading to the machine body.
[0013]
Also, if there is an abnormality in the seal that connects the rotary shaft flow path and the fixed-side flow path, a large amount of coolant leaks, and if this coolant enters the electric motor or bearing section, it will cause an electric leakage accident or seizure accident. The coolant leakage from the seal part is constantly monitored by the detecting means.
Therefore, it performs an operation stop of the rotary joint by performing a power failure of the fluid pump and the machine body automatically detects a large amount of coolant leakage into the initial abnormality occurrence without hands from the sealing portion, on the downstream side The effect of preventing damage to the device can be obtained.
[0014]
Moreover, in the first chamber which is isolated by enclosing the sheet Lumpur unit, Keru receiving leakage fluid when the amount of leakage from the seal portion is in the range of normal. If the seal becomes abnormal due to breakage, etc., that is, if the discharge amount of the coolant greatly exceeds the normal range, it will leak to the downstream side, the second chamber will receive the leaked coolant and the leaked coolant will enter the spindle side. To prevent.
Therefore, the effect of draining this received second chamber even when unable to wastewater treatment leakage coolant in the first chamber when there is abnormality in sheet Lumpur portion, to reliably prevent the damage on the downstream side of the device Is obtained.
[0015]
In the rotary joint according to the second aspect, air purging is performed upstream in the gap between the partition walls separating the chambers and the surface of the rotary shaft. The amount of coolant discharged greatly exceeds the normal range due to breakage of the seal portion, and the leakage from the first chamber to the second chamber side is attempted through a 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 in the gap prevents entry into the second chamber side.
Therefore, in the rotary joint according to claim 2, even in the event that an abnormal situation in the coolant leakage from the seal portion of Russia over Tali joint occurs, it is strictly protected without penetrating the coolant leaks on the downstream side equipment effect of can be Runado is obtained.
[0016]
Also, detection known means immediately detects the leakage coolant to be entering the downstream leaks, i.e. through the partition wall separating the first chamber and the second chamber into the second chamber from the first chamber.
Therefore, automatically detect leakage coolant before entering the second chamber, the effect is obtained that such spindle motor even if an abnormality occurs in the rotary joint seal portion can be prevented from incurring damage .
[0017]
In the rotary joint according to claim 3 , the rotating shaft is a rotating shaft in a machine tool, and even if there is an abnormality in the seal part of the rotary joint, the leakage coolant does not enter from around the main shaft or the main shaft motor rotor shaft, Abnormalities can be automatically detected to prevent damage to important parts such as bearings and spindle motors. 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.
[0018]
In the rotary joint according to claim 4, by performing air purge toward the upstream side in the gap between the partition walls separating the chambers and the surface of the rotary shaft, the leakage coolant is used as detection means by the force of the purge air flow. Because it is a detection method that pushes it in so that it can be pushed in, detection can be performed quickly and reliably, and the introduction port can be set in a narrow place. The effect of being able to do is acquired.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the rotary joint of the first embodiment, FIG. 2 is an explanatory view showing the positional relationship between the detection sensor mounting and the drain, and FIG. 3 (a) is an enlarged explanatory view of the upstream partition wall air purge section. (B) is an enlarged explanatory view of the downstream partition wall air purge section.
In the present embodiment, the case where the rotary joint A is mounted on a horizontal main shaft will be described. Of course, this configuration is not limited to the horizontal type, but can be mounted on a vertical main shaft.
In the figure, reference numeral 1 denotes a frame of the main shaft motor, and reference numeral 2 denotes a rotor shaft as a main shaft whose end is projected from the frame 1, and a flow path 3 is perforated on the axis.
[0020]
First, the housing 4 of the rotary joint A is closed at one end side by a support plate 6 of a floating sheet 5, and the other end side is concentric with the rotor shaft 2 and fixed to the frame 1 of the main shaft motor by a flange 7.
The support plate 6 is provided with an opening 8 for placing the floating sheet 5, and a floating sheet mounting portion 9 is fitted from the outside so as to seal the opening 8. Although not shown, the floating sheet mounting portion 9 is provided with a seal hole communicating with the coolant supply path 10, and the floating sheet 5 is constrained from rotating by the guide pin 11, and the leading end portion of the seal hole is placed in the seal hole. It is slidably attached to.
[0021]
A rotary tube shaft 12 is screwed into the rotor shaft 2 and is disposed so that a seal ring 14 fixed to the front end portion faces a seal ring 13 fixed to the rear end portion of the floating sheet 5. . Accordingly, the coolant pumped from the supply path 10 presses and slides the floating sheet 5 to bring the seal ring 13 into close contact with the seal ring 14, thereby allowing the flow path 3 of the rotor shaft 2 to pass through the respective flow paths. To be supplied.
[0022]
The interior of the housing 4 is divided into three chambers from the upstream side to the downstream side by the two partition walls 15 and 16. That is, the upstream partition 15 is disposed so as to penetrate only the rotary tube shaft 12, thereby enclosing the seal portion 17 including the seal rings 13 and 14 between the support plate 6 of the floating sheet. A first chamber 18 is formed for isolation. A large-diameter drain port 19 is opened at the lower portion of the first chamber.
The downstream partition wall 16 is located between the upstream partition wall 15 and the main shaft motor frame 1 so as to pass through the rotor shaft 2. A second chamber 20 is formed, and a third chamber 21 is formed between the second chamber 20 and the frame 1. A large-diameter drain port 22 is provided at the lower portion of the second chamber 20. In the present embodiment, the third chamber 21 is not provided with a drain port for piping, but is provided with an opening such as a small-diameter drain port or a slit.
[0023]
Further, as shown in detail in FIGS. 3 (a) and 3 (b), the partition walls 15 and 16 perform air purging on the respective outer peripheral surfaces in the gap between the rotating tube shaft 12 and the rotor shaft 2 penetrating. Is provided. Among them, two annular grooves 23 and 23 are provided around the through hole of the partition wall 15 and communicated with an air supply port 25 opened in the housing by air flow paths 24 and 24, respectively. Similarly, one annular groove 26 is provided around the through hole of the partition wall 16 and communicates with the air supply port 25 through an air flow path 27.
The annular groove 26 is formed to be larger than the annular grooves 23 and 23 so as to be purged with air more than the annular grooves 23, 23. Further, in each annular groove, the upstream gap Sa is made larger than the downstream gap Sb and the upstream side. The air purge amount toward is increased.
[0024]
Leakage coolant detection means is provided using the upstream partition 15.
A detection groove 28 for leaking coolant is provided between the annular grooves 23, 23, and a detection flow path 30 is extended to the detection port 29 of the housing. Reference numeral 31 denotes a detection sensor, which is attached to the detection port 29 via a connector 32. The connector 32 passes through the detection flow path 30 directly through a detection path having a relatively large diameter, and a liquid receiving chamber 34 in which a detection unit 33 composed of a pair of electrodes is disposed, and purge air is released from the liquid receiving chamber 34. An air vent 35 is opened.
[0025]
Next, the operation and effect of the present embodiment will be described.
In the rotary joint A configured as described above, the floating seat 5 is first slid downstream in the first chamber by the hydraulic pressure of the coolant supplied from the outside before the main shaft motor is started. The ring 13 is brought into close contact with the seal ring 14 at the tip of the rotary tube shaft 12. In this state, the coolant flow path communicates with the rotor shaft flow path 3 from the supply port 10 via the seal portion 17 of the first chamber 18, and the coolant is supplied to the tool tip with pressure. When the coolant is supplied and stopped, the seal rings are attached and detached so that the coolant leaks little by little, but is discharged from the drain port 19 in the first chamber 18 each time.
[0026]
The purge air is supplied from the air supply port 25 together with the supply of the coolant. This purge air is branched into an upstream partition 15 direction and a downstream partition 16 direction at an air supply port 25, and the partition 15 side is supplied to the annular grooves 23 and 23 by a pair of air flow paths 24 and 24, respectively. In the annular groove on the upstream side, the outer peripheral surface of the rotary tube shaft 12 is air purged from the upstream clearance Sa toward the first chamber 18, and in the detection groove 28 in the downstream clearance Sb. Further, in the downstream annular groove, air is purged from the upstream gap Sa into the detection groove 28 and leaks slightly from the downstream gap Sb toward the second chamber 20. In this case, since the upstream clearance Sa> the downstream clearance Sb, the air pressure in the annular grooves 23 and 23 and the detection groove 28 is higher in the downstream groove than in the upstream groove. The flow flows from the downstream side to the upstream side and the detection flow path 30 side.
Further, also in the downstream partition 16, the outer peripheral surface of the rotor shaft 2 is air purged from the upstream clearance Sa toward the second chamber 20. Only a slight leak will occur downstream.
In the air purge state, purge air is discharged to the outside through the drain ports 19 and 22 in the first chamber and the second chamber, and the detection groove 28 is vented by the liquid receiving chamber 34 via the detection flow path 30 and the detection path 36. It is discharged from the mouth 35 to the outside.
[0027]
In this state, the spindle motor is started and the machine tool is in operation. If an abnormal state of the seal portion occurs during this operation, for example, a large amount of coolant leaks due to damage to the seal ring 13 or 14, the seal portion 17 is in the first chamber 18, so the leaked coolant is discharged from the drain port 19. Is done. When the amount of leakage exceeds the amount of drainage from the drain port 19, the leakage coolant fills the first chamber 18 and reaches the penetration portion of the upstream partition 15 by the rotary tube shaft 12.
Air is purged from the through portion of the rotary tube shaft 12, that is, the upstream clearance Sa, and the coolant is prevented from entering. However, when the coolant pressure wins and enters the clearance Sa, the detection groove 28 downstream from the clearance Sa. The coolant that has reached the point is immediately sent from the detection flow path 30 to the liquid receiving chamber 34 on the air purged air from the annular groove 23 on the downstream side. In the liquid receiving chamber 34, when the leakage coolant short-circuits the detection unit 33 composed of a pair of electrodes, the circuit from the control unit is closed and a leak is output.
Upon receiving this signal, the control unit immediately shuts off the coolant pump and stops the coolant supply. Also, the power supply of the spindle motor is shut off and only air purge is performed.
The leaked coolant that has entered the gap between the partition walls 15 is blown back to the upstream side because the groove disposed downstream is higher than the groove disposed upstream in the air pressure in the annular grooves 23 and 23 and the detection groove 28. In addition, it is less likely to enter the downstream side. Even when there is a very large amount of leakage and leakage coolant enters the gap of the partition wall 16, the air pressure in the annular groove 26 is similarly blown back to the upstream side by setting the upstream gap Sa> the downstream gap Sb. In addition, there is little possibility of leakage coolant entering the third chamber 21 on the downstream side.
[0028]
As described above, in the rotary joint A of the present embodiment, first, the interior of the housing is divided into the three chambers 18, 20, and 21 from the upstream side to the downstream side, and the seal portion 17 is separated from the first chamber. Therefore, it is possible to prevent the coolant leaking from the seal portion 17 from entering the main shaft side in two stages.
In the partition walls 15 and 16 forming the three chambers, air purge is performed from the gaps through which the respective shafts penetrate, so that the intrusion of leaking coolant can be more strictly prevented.
Since the downstream air purge has a higher pressure than the upstream air purge, it is possible to prevent the leakage coolant from being pushed downstream by the upstream air purge.
In the upstream partition 15, the leaked coolant that has entered from the gap Sa reaches the liquid receiving chamber 34 side on the purge air flowing into the detection flow path 30 from the detection groove 28 and can be immediately detected by the sensor. It is possible to prevent leakage to the downstream side and to prevent a large damage from occurring.
Since the detection sensor 31 detects the portion where the downstream leakage of the coolant has occurred in the rotary joint housing, it is possible to perform processing for preventing the occurrence of damage immediately after the coolant leakage due to the seal portion abnormality.
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.
[0029]
Next, Embodiment 2 will be described with reference to FIG. The rotary joint B of the present embodiment shows a state of being attached to the vertical axis type, but of course, it can also be used as a horizontal axis type. In the present description, the same components as those in the first embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.
The rotary joint B of the second embodiment is different from the first embodiment in the downstream side partition wall structure and the air purge method.
[0030]
In the figure, reference numeral 40 denotes a rotating flange fixed to the rotary tube shaft 12, and 41 denotes a fixed side partition fixed to the inner wall of the housing, and this set constitutes a downstream side partition.
The rotary flange 40 is disc-like and has an annular groove 42 on the outer peripheral surface provided very close to the inner peripheral surface of the housing 4, and is provided separately from the air supply port 25 for air purging the upstream partition 15. The air supply port 43 is purged with air. The air supply port 43 is set so that the air purge pressure is higher than that of the air supply port 25.
The fixed partition wall 41 forms a third chamber 21 between itself and the frame 1 of the spindle motor, and rises upward. A vertical inner peripheral surface portion in which the vertical outer peripheral surface upper end portion 44 is provided on the outer peripheral portion of the rotary flange 40. The labyrinth seal 45 is mounted between the vertical surfaces. From the upstream partition 15 to the labyrinth seal 45 is the second chamber 20, and the detection port 29 is located in the upper surface of the rotary flange 40 (that is, the upper portion where the second chamber is divided by the air purge portion). And the drain port 22 of the second chamber is perforated between the rotary flange 40 and the stationary partition 41 (that is, the lower portion where the second chamber is divided by the air purge portion).
[0031]
Next, the function and effect of the second embodiment will be described.
In the rotary joint B of the second embodiment, first, an abnormality occurs in the seal portion 17, and the discharge from the first chamber 18 is insufficient for the discharge from the drain port 19 of the first chamber 18, and leaks into the second chamber 20. When the coolant has entered, the leaked coolant that has reached the rotating flange 40 disposed in the second chamber 20 is brought close to the outer periphery by centrifugal force. Since the air purge is performed upward on the outer periphery, the leaked coolant is introduced on the purge air flowing into the detection port 29 without leaking downward due to the air purge pressure, and is immediately detected by the detection sensor.
Therefore, in the rotary joint B of the present embodiment, it is possible to detect the leakage of the coolant well before the leakage coolant reaches the spindle motor even when the spindle motor is on the downstream side particularly in the vertical type.
In order to make the downstream air purge larger than the upstream air purge, pressure-controlled ones are introduced from the outside, so that the pressure difference is reliably obtained and the upstream air purge is strictly prevented from pushing the leakage coolant into the spindle motor. The effect that it can be obtained.
Further, in the rotary joint B in this embodiment, even if leakage coolant enters the second chamber 20, the leakage is detected at that time and the pump is stopped, so there is no further entry. In addition, since the drain port 22 is at the bottom of the second chamber 20, it can be quickly discharged, and even if leaked coolant accumulates at the bottom, the labyrinth seal 45 that partitions the second chamber 20 and the third chamber 21 from the water surface Since a sufficient height is secured, the risk of flooding the third chamber 21 is extremely low.
[0032]
Although the embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to this embodiment.
For example, the number of partition walls is arbitrary, and the optimal number of arrangement can be selected in terms of function.
Although the seal portion has been described as bringing a pair of seal rings into close contact with each other by the pressure of the coolant to communicate the flow path, it is not limited to the structure of the seal portion.
In the case of a sensor that detects the leakage coolant coming into contact with the electrode, a heater for preventing condensation may be provided, or hot air or dry air may be blown onto the electrode portion in advance by another path and dried.
The air purging annular groove 26 and the air flow path 27 of the downstream partition 16 may be omitted if the discharge from the drain port 22 of the second chamber 20 is sufficient.
The number of air purging annular grooves 23 provided in the upstream partition 15 is not limited, and may be three or more or one.
Although detection of leakage (leakage coolant) has been described with an electrode type, the type of detection sensor is arbitrary, and various methods such as a method of optically detecting droplets can be employed.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a rotary joint A according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a positional relationship between the detection sensor mounting and the drain according to the first embodiment.
FIGS. 3A and 3B show an air purge unit according to the first embodiment, where FIG. 3A is an enlarged explanatory view showing an upstream partition air purge unit, and FIG. 3B is an enlarged explanatory view showing a downstream partition air purge unit.
4 is a sectional view showing a rotary joint B according to Embodiment 2. FIG.
[Explanation of symbols]
A, B Rotary joint Sa Upstream clearance Sb of air purge section Downstream clearance of air purge section 1 Spindle motor frame 2 Spindle motor rotor shaft 3 Rotor shaft flow path 4 Housing 15 Upstream partition 16 Downstream partition 17 Seal Portion 18 First chamber 19 First chamber drain port 20 Second chamber 21 Third chamber 22 Second chamber drain port 23 Annular groove in upstream partition (air purge)
24 Air flow path (Air purge)
26 Downstream partition annular groove (air purge)
27 Air flow path (Air purge)
28 Detection groove 29 of leakage coolant 29 Detection port 31 of housing Detection sensor 40 Rotating flange (upstream partition)
41 Fixed bulkhead (upstream bulkhead)
42 Annular groove of rotating flange (air purge)

Claims (4)

It has a seal part that communicates the rotary shaft flow path of the rotary shaft and the fixed side flow path, and includes a detecting means for detecting an abnormality of the seal part ,
The detection means monitors leakage from the seal portion, and the first chamber that receives the leaked liquid when the amount of leakage from the seal portion is within a normal range and the first chamber are partitioned by a partition wall. And has a second chamber that receives the leaked liquid from the first chamber when leaking greatly beyond the normal range,
Two annular grooves are provided around the through hole of the partition wall and communicated with the air supply port through the air flow path,
A detection groove for leaking coolant is provided between two annular grooves in the through hole, and the second chamber extends from the first chamber to a liquid receiving portion communicated through a detection flow path extending from the detection groove. A rotary joint characterized in that a detecting means for detecting leaked liquid when it flows into the chamber is arranged . There is a gap between the partition wall separating the first chamber and the second chamber and the surface of the rotary shaft, and the upstream gap on the first chamber side of the gap is more than the downstream gap on the second chamber side. The rotary joint according to claim 1, wherein the rotary joint is formed so as to increase the amount of air purge toward the upstream side which is the first chamber side . The rotary joint according to claim 1 or 2 , wherein a machine tool is provided with a rotating shaft . 4. The apparatus according to claim 1, wherein an air vent opening for allowing purge air to escape from the liquid receiving portion is provided so that leakage liquid is introduced into the detection means by the force of the purge air. Rotary joint as described in

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