JP2007120694A - Rotary joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary joint capable of reducing a stagnant portion of grease and effectively preventing the solidification of the grease. <P>SOLUTION: The rotary joint 1 includes a casing 33, a tube-like rotor 35 protruding from the casing 33, a pair of bearings for rotatably supporting the rotor 35 in the casing 33, a spacer 41 for forming a clearance between the pair of bearings, a tube-like inner tube 43 provided inside the rotor 35, a seat ring 45 attached to the other end side end of the rotor 35, a sealing ring 47 for sealing the inside of the rotor 35 in cooperation with the seat ring 45 at at the other end side position of the rotor 35 and a spring 49 for pressing and energizing the seal ring 47. An outside position of the spacer 41 is positioned at least outside the center of a rolling element of a first bearing 37 and a flow passage for making the grease flow to the first bearing 37 and a second bearing 38 is provided for the spacer 41. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotary joint used for adjusting the temperature (especially high temperature) of a roll.

The rotary joint is attached to, for example, a shaft portion of a rotating roll, and is used for the purpose of adjusting the temperature of the roll by introducing and discharging a heat medium or a refrigerant fluid into the roll.
As this rotary joint, what is shown by patent document 1, for example is proposed.
This includes a casing, and the casing has a pair of bearings spaced axially so as to rotatably support a tubular rotor having an outer end extending from the casing, and penetrates the inside of the rotor. To support the inner pipe arranged. The inner end portion of the rotor is provided with an annular seat ring having a flat surface, and the casing is provided with a seal ring which is installed so as to be movable in the axial direction so as to face the seat ring. By energizing in the direction of the seat ring, the inside of the rotor and the bearing portion of the casing are sealed.
The protruding end of the rotor is connected to a rotating roll, and one end of the inner tube is positioned in the roll.
The fluid supplied from the pipe connected to the other end of the inner pipe is supplied into the roll and discharged through between the rotor and the inner pipe.

JP-A-6-235486 (FIG. 1)

In such a rotary joint, grease is used for lubricating a pair of bearings. In rotary joints that handle high-temperature fluids, urea grease, which is said to be heat-resistant, is often used.
Grease fills the bearings and the space between them. As the rotor rotates, the inner ring and the spacer rotate, and the grease flows and functions as a lubricant. And a part flows out from a bearing outside.
At this time, the grease self-heats by resisting rotation, and further receives heat from a high-temperature fluid, and the temperature rises. When the work is finished, it is cooled and returns to a semi-solid state. By repeating this, the grease deteriorates and eventually solidifies.
Moreover, it heat-degrades and solidifies by the continuous heating for a long time accompanying a continuous driving | operation.
These start at the part in contact with the rotating body, which gradually progresses outward, and can eventually develop into a situation where the bearing is locked.
Also, when the grease flowing out from the bearing toward the seal ring solidifies and grows, it pushes the seal ring against the spring, that is, the solidified grease adheres the seal ring and prevents its movement. Become.
As a result, the seal between the seal ring and the seat ring is broken, and the fluid passing through the rotor flows into the bearing portion.
On the other hand, when the grease flowing out from the bearing is solidified, the appearance is deteriorated, and there is a risk that the surrounding contamination will occur due to the scattering of the grease and the bearing may be locked.

  In view of the above problems, an object of the present invention is to provide a rotary joint that can reduce the staying portion of grease and effectively prevent the grease from solidifying.

In order to solve the above problems, the present invention employs the following means.
That is, the rotary joint according to the present invention includes a casing having an open space opened to one end side, a tubular rotor disposed at the other end side in the open space and protruding from the casing, A pair of bearings that rotatably support the rotor with respect to the casing, a spacer that is mounted between the pair of bearings and that has a space between them, and a casing that penetrates the inside of the rotor. An attached tubular inner tube, a seat ring attached to the other end of the rotor, and a seat ring attached to the other end of the rotor so as to be movable in the axial direction relative to the casing; A seal ring that seals the open space and the interior of the rotor in cooperation with the spring, and a spring that presses and urges the seal ring toward the seat ring, The rotary joint is provided, wherein the spacer has an outer position at least outside a center position of the rolling element of the bearing, and is provided with a flow path through which grease flows toward each bearing. It is characterized by.

As described above, the spacer that provides a gap between the pair of bearings has an outer position located at least outside the center position of the rolling element of the bearing, and thus a space formed by the casing, the pair of bearings, and the spacer. Becomes smaller. When this space becomes small, the amount of grease staying here decreases, so the staying period becomes shorter. For this reason, possibility that deterioration will progress and it will solidify can be reduced significantly.
Further, since the spacer is provided with a flow path for allowing grease to flow toward each bearing, the fluidized grease can easily flow toward the bearing. As a result, the grease is less likely to be repeated between the fluidized state and the semi-solid state, so that the possibility of progress of deterioration and solidification can be further reduced.

  In the rotary joint according to the present invention, the spacer has a middle-high shape in the axial direction, and an outer surface forms the flow path.

Thus, since the spacer has a middle and high shape in the axial direction, the space formed by the casing, the pair of bearings, and the spacer is further reduced. In addition, since the outer surface of the spacer is inclined inward from the central portion in the axial direction toward the bearing to form a flow path, the fluidized grease is supplied to the bearing using this inclination.
Thereby, the possibility that the deterioration of the grease progresses and solidifies can be further reduced.

  In the rotary joint according to the present invention, the portion of the spacer that contacts the grease is formed of a fluororesin.

Thus, since the part which contacts the grease of a spacer is formed with the fluororesin, the peelability from grease is good.
For this reason, since the retention of grease is reduced, the possibility that the deterioration of the grease progresses and solidifies can be further reduced.
Note that polytetrafluoroethylene (PTFE) is suitable as the fluororesin.

  Further, in the rotary joint according to the present invention, the spacer is arranged on the inner side to define a space between the pair of bearings, and the grease is arranged on the outer side of the spacer part and supplies the grease to the bearings. It is characterized by comprising a supply unit.

  Thus, the spacer is composed of a spacer portion that is disposed on the inner side and defines a distance between the pair of bearings, and a grease supply portion that is disposed on the outer side of the spacer portion and supplies grease to each bearing. The part and the grease supply part can be appropriately formed with an appropriate shape and material. Thereby, the freedom degree of design can be improved.

  The rotary joint according to the present invention is characterized in that a seal member configured to cover the periphery of the rotor is provided between the bearing on the other end side and the seal ring.

Thus, since the seal member configured to cover the periphery of the rotor is provided between the bearing on the other end side and the seal ring, the grease flowing out from the bearing is stopped by the seal member, and the seal ring No longer flows out.
For this reason, since grease does not exist between the seal ring and the seat ring, it is possible to prevent a situation where the grease is solidified and pressed against the seal ring. As a result, the seal between the seal ring and the seat ring is broken, and high temperature fluid can be prevented from flowing toward the bearing.
Specifically, the inner diameter of the seal member and the outer diameter of the rotor are approximately the same, and the rotation of the rotor causes the seal member to be slightly worn and settled with almost no gap.

  In the rotary joint according to the present invention, the seal member includes a guide surface for guiding grease on the rotor side, and a grease discharge portion at a lower portion.

As described above, since the seal member is provided with the guide surface for guiding the grease to the rotor side, the grease flowing out from the bearing is guided by the guide surface of the seal member, moves to the lower part, and is discharged out of the system from the lower part. .
For this reason, since the grease is not retained by the seal member, it is possible to prevent deterioration and solidification in this portion.

  In the rotary joint according to the present invention, the grease uses a lithium complex as a thickener.

  Thus, since the grease uses lithium complex as a thickener, the increase in viscosity due to deterioration is very small. For this reason, since the time until solidification can be made, it is possible to prevent the grease from solidifying.

According to the present invention, the spacer that provides a gap between the pair of bearings has an outer position located at least outside the center position of the rolling element of the bearing, so that the amount of remaining grease is reduced and deteriorated. The possibility of solidification and solidification can be greatly reduced.
In addition, since the spacer is provided with a flow path for allowing grease to flow toward each bearing, the possibility of progress of deterioration and solidification can be further reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First embodiment]
A rotary joint 1 according to a first embodiment of the present invention will be described with reference to FIGS.
The rotary joint 1 of this embodiment is attached to an extruder 3 that manufactures a biaxially stretched film sheet.
FIG. 1 is a perspective view showing the overall schematic configuration of the extrusion molding machine 3.
The extrusion molding machine 3 includes an extruder 5, a die 7, a casting 9, a longitudinal stretching machine 11, a lateral stretching machine 13, a take-up machine 15, and a winder 17.

The extruder 5 has a configuration in which, for example, a screw is disposed in a cylinder.
The extruder 5 has a function of heating and pressurizing while feeding the supplied resin, which is a molding material, by a rotating screw, plasticizing the resin, further homogenizing, weighing, and pressurizing the resin and sending it to the die 7. Play.
In the die 7, for example, a slit is formed by a pair of main bodies arranged with a gap therebetween.
The die 7 has a function of forming the resin into a sheet shape along the slit shape by supplying the plasticized resin from one end of the slit and extruding the resin from the other end.

The casting 9 is constituted by, for example, a rotating large-diameter cooling roll.
A rotary joint 1 to be described later is installed at the shaft end of the cooling roll. The cooling roll keeps the roll peripheral surface at a low temperature by supplying cooling water from a cooling water supply means (not shown) to the inside through the rotary joint 1.
The casting 9 has a function of guiding the plasticized sheet-like resin extruded by the die 7 in contact with the peripheral surface of the cooling roll, and rapidly cooling and solidifying the resin to form the original sheet 21. .
As the casting 9, various methods such as a method in which a resin molded into a sheet shape is dipped in a cooling water tank or a method in which the resin is passed through a plurality of cooling rolls can be used.

The longitudinal stretching machine 11 stretches the original sheet 21 in the traveling direction, for example, stretches it several times to form a film 31.
As shown in FIG. 2, the longitudinal stretching machine 11 is provided with a number of temperature raising rolls 23 that sequentially guide the raw sheet 21.
The rotary joint 1 is attached to one shaft portion 25 of the temperature raising roll 23. (See Figure 3)

The temperature raising roll 23 is supplied with steam, hot water or heated oil from the rotary joint 1 and heated to a high temperature, for example, hundreds of degrees Celsius, and the temperature is adjusted to maintain it. .
A number of the temperature raising rolls 23 are controlled so that the peripheral speed becomes faster as going to the downstream side in the flow direction of the raw sheet 21.
A nip roll 27 is provided on the heating roll 21 whose speed on the downstream side is increased, and presses the original fabric sheet 21 toward the heating roll 23 so that the heating roll 23 reliably drives the original fabric sheet 21. Is provided.

The transverse stretching machine 13 further heats the film 31 stretched in the longitudinal direction by the longitudinal stretching machine 11, heats the film 31 to, for example, hundreds of degrees Celsius, and stretches it in the transverse direction, for example, extends it several times in width.
The transverse stretching machine 13 is provided with a heating means for the film 31, a grip for holding both ends of the film 31, and a tenter rail for guiding the grip 31 to move in the lateral direction while moving the grip. (Not shown)
The take-up machine 15 performs cutting of the end portion (ear portion) of the film 31, measurement of the film thickness using the thickness gauge 29, surface treatment of the film 31, and the like.
The winder 17 winds the film 31 sent from the take-up machine 15 on a roll.

Next, the rotary joint 1 will be described with reference to FIGS.
FIG. 4 is a longitudinal sectional view showing the entire configuration of the rotary joint 1.
The rotary joint 1 includes a casing 33, a rotor 35, a first bearing 37 and a second bearing 38 (a pair of bearings), a spacer 41, an inner tube 43, a seat ring 45, a seal ring 47, and a spring. 49, a lubricating seal (seal member) 51, and a scraper 53 are provided.

The casing 33 is made of steel, and three cylinders having different diameters are connected in the order of size, and a large diameter portion 55, a medium diameter portion 57, and a small diameter portion 59 are formed from one end side (the right side in FIG. 4). Yes.
The large diameter portion 55 is provided with a large diameter hollow portion (open space) 61 opened to one end side.
The rotor 35 is made of stainless steel and has a substantially circular tube shape. The rotor 35 has substantially the same axial center as the large-diameter hollow portion 61 and is disposed so as to protrude to one end side.
The rotor 35 is rotatably supported with respect to the casing 33 by a first bearing 37 and a second bearing 38.

A flange 39 for attaching to the shaft portion 25 is fixed to one end side of the rotor 35 by welding.
On the outer periphery of the other end side (left side in FIG. 4) of the rotor 35, a screw 63 is cut within a predetermined range and a groove 65 is provided in the axial direction. (See Figure 5)
A seat ring 45 having an inner diameter substantially the same as that of the rotor 35 and a smaller outer diameter is fitted to the end face of the other end of the rotor 35.
The seat ring 45 is made of ceramic, and a smooth sliding surface 67 is provided on the other end side.

The first bearing 37 includes an outer ring 69, a ball (rolling element) 71, and an inner ring 73.
The second bearing 38 is provided with an outer ring 70, balls (rolling elements) 72, and an inner ring 74.
The distance between the first bearing 37 and the second bearing 38 is regulated by a spacer 41 interposed between the inner rings 73 and 74.
The outer ring 69 of the first bearing 37 is restricted to move toward one end by a C-shaped retaining ring 75 attached to the inner surface of the casing 33, and the inner ring 73 is restricted by a protrusion provided on the outer periphery of the rotor 35.
The position of the outer ring 70 of the second bearing 38 is regulated by a protrusion provided on the inner surface of the casing 33.

The other end side end portion of the inner ring 74 of the second bearing 38 is located at one end side portion of the screw 63 of the rotor 35.
The position of the inner ring 74 is regulated by a washer 75 and a star nut 77 attached to the other end of the rotor 35.
The washer 75 has a thin ring shape, and a plurality of claws 79 inclined toward the other end are provided on the outer peripheral portion, and a guide portion 81 is provided on the inner peripheral portion to be fitted in the groove 65.
The washer 75 is movable in the axial direction with the guide portion 81 guided by the groove 65.
The star-shaped nut 77 has a ring shape, has an outer diameter that engages with the root portion of the claw 79 of the washer 75, and includes a plurality of recesses 83 penetrating in the axial direction on the outer peripheral portion.
The star nut 77 regulates the position of the other end side of the inner ring 74 by screwing the inner peripheral screw with the screw 63 of the rotor 35 and pressing the washer 75 against the other end side of the inner ring 74.

The spacer 41 is made of steel and has a substantially cylindrical shape.
The inner peripheral surface of the spacer 41 is engaged with the outer periphery of the rotor 35.
The outer peripheral surface of the spacer 41 is positioned so that both end portions in the axial direction are substantially at the same position as the center positions of the balls 71 and 72, and protrudes so as to have a middle height in the axial direction.
The spacer 41 has an intermediate position protruding outward in the axial direction, and an inclined surface (flow path) 85 inclined inward toward the first bearing 37 and the second bearing 38 is formed.
The inclined surface 85 may be coated with a fluororesin, for example, PTEF. By doing so, the releasability from the grease is improved, and the flow of grease becomes smooth.
The casing 33 is provided with a grease nipple 87 for supplying grease to the upper portion at a position corresponding to an intermediate position in the axial direction of the spacer 41 and an opening 89 for attaching a member for discharging grease to the lower portion.

The medium diameter part 57 is provided with a medium diameter hollow part 91 having substantially the same axial center as the large diameter hollow part 61.
The seal ring 47 is made of special carbon and has a tubular shape. The seal ring 47 is fitted to one end side of the medium-diameter hollow portion 91 so as to be movable in the axial direction, and is guided in the axial direction by a pin 93 attached to the casing 33.
The seal ring 47 protrudes toward the large-diameter hollow portion 61. The end face on one end side of the seal ring 47 is formed to be smooth and is in contact with the sliding face 67 of the seat ring 45 to form a sealing portion.

An O-ring 95 is attached to the other end of the seal ring 47 between the casing 33 and the medium diameter portion 57.
A ring-shaped spring receiver 97 is engaged with the other end of the O-ring 95.
The spring receiver 97 is urged to one end side by a spring 49 disposed in the medium-diameter hollow portion 91 to compress the O-ring 95.
As a result, the seal ring 47 is pressed in the axial direction via the O-ring 95 and pressed against the sliding surface 67 of the seal ring 47.

The small-diameter portion 59 is provided with a small-diameter hollow portion 99 having substantially the same axial center as the medium-diameter hollow portion 91 passing therethrough.
The other end side of the inner tube 43 is rotatably supported by the small diameter hollow portion 99.
The inner tube 43 is made of stainless steel and has a tubular shape. The inner tube 43 is integrally supported by the rotor 35. A connecting pipe 101 is attached to one end side of the inner pipe 43.
A roll inner tube 103 located in the temperature raising roll 23 is attached to the connecting tube 101 via an O-ring.

A supply pipe 105 is attached to the other end side end of the small diameter part 59 by an attachment pipe 107.
The supply pipe 105 is connected to a heat medium generation source (not shown), and supplies steam, hot water, or heated oil into the heating roll 23 via the inner pipe 43, the connecting pipe 101, and the roll inner pipe 103.
The middle diameter portion 57 is provided with a discharge space portion 109 so as to communicate with the middle diameter space portion 91.
The discharge space portion 109 functions as a discharge port for steam, hot water, or heated oil flowing out from the temperature raising roll 23 passing between the rotor 35 and the inner pipe 43.

Next, the lubricating seal 51 will be described with reference to FIGS.
The lubricating seal 51 has a ring shape, and an inner peripheral portion is fitted to the other end side of the rotor 35.
The outer peripheral portion of the lubrication seal 51 protrudes to one end side and forms a space 111 whose diameter gradually increases. One end side surface of the lubricating seal 51 forming this space 111 constitutes the guide surface 113 of the present invention.
The end face 115 on the one end side of the lubricating seal 51 is disposed so as to contact the outer ring 70 of the second bearing 38.
A pin hole 117 is provided in the upper part of the lubricating seal 51. The lubrication seal 51 is positioned by a pin 119 inserted into the pin hole 117 through the casing 33.
At the lower part of the lubrication seal 51, a discharge part 121 having a notched protrusion is provided.

A scraper 53 is attached to a lower portion on one end side of the large diameter portion 55.
The scraper 53 is a plate material, and is attached so that the upper portion is in contact with one end side of the first bearing 37.
A grease receiver 125 that receives the grease guided by the scraper 53 is attached to one end side of the scraper 53.
The grease receiver 123 includes a guide plate 125 that extends in the up-down direction, and a U-shaped cross-section grease tray 127 that is attached orthogonally to the lower portion on the other end side of the guide plate 125.
The guide plate 125 is attached to the scraper 53 substantially orthogonally.
The grease receiving tray 127 is provided over substantially the entire length of the large diameter portion 55 in the axial direction.

Operation | movement of the extruder 3 using the rotary joint 1 concerning this embodiment demonstrated above is demonstrated.
The resin as the molding material is heated and pressurized by the extruder 5 and plasticized. The extruder 5 further homogenizes this resin, measures it to a required amount, raises the pressure, and sends it to the die 7.
The resin sent to the die 7 is formed into a sheet shape along the slit shape of the die 7.
This sheet-like resin is rapidly cooled and solidified by the cooled large-diameter roll while moving along the large-diameter roll of the casting 9.
In this way, the original fabric sheet 21 is formed.

The original fabric sheet 21 is sent to the longitudinal stretching machine 11.
Steam, hot water, or heated oil is supplied from a heating medium generation source (not shown) into the temperature rising roll 23 by the rotary joint 1 attached to the shaft portion 25 of the temperature increasing roll 23. Maintained at 10 ° C.
The original fabric sheet 21 is heated and softened while being conveyed in contact with the peripheral surface of the temperature raising roll 23.
A number of the temperature rising rolls 23 are controlled so that the peripheral speed becomes faster as going to the downstream side in the flow direction of the original fabric sheet 21, so that the softened original fabric sheet 21 is sequentially pulled to the downstream temperature increasing roll. And stretched in the flow direction.
In this way, the longitudinal stretching machine 11 stretches the original fabric sheet 21 in the traveling direction, for example, extends it several times to form a film 31.

The film 31 stretched in the traveling direction by the longitudinal stretching machine 11 is sent to the lateral stretching machine 13.
The film 31 is conveyed with both ends held by grips.
The film 31 is heated to, for example, hundreds of degrees C. by the heating means. Next, the film 31 is stretched in the lateral direction by moving the grip in the lateral direction along the tenter rail, for example, three times as wide.
The film 31 is cut at both end portions (ear portions) by the take-up machine 15 so as to have a required width, the thickness is measured by the thickness gauge 29, and surface treatment is performed.
The film 31 is wound on the roll of the winder 17.

Next, the operation of the rotary joint 1 in the temperature raising roll 23 of the longitudinal stretching machine 11 will be described.
Since the flange 39 fixed to the rotor 35 is bolted to the end face of the shaft portion 25 of the temperature raising roll 23, the rotor 35 and the inner tube 43 rotate at the same angular velocity as the temperature raising roll 23.
Since the casing 33 rotatably supports the rotor 35, the casing 33 is fixed regardless of the rotation of the rotor 35. Further, the seal ring 47, the scraper 53, the grease receiver 123 and the like attached to the casing 33 remain in a fixed position.

Steam, hot water, or heated oil supplied from a heat medium generation source (not shown) by the supply pipe 105 passes through the inner pipe 43, passes through the connecting pipe 101 and the roll inner pipe 103, and reaches the heating roll 23. Introduced into the interior space.
The introduced steam, hot water or heated oil passes through the space between the rotor 35 and the inner pipe 43 after being heated by the heating roll 23 and is discharged from the discharge space 109 to the outside of the system.
One end side end surface of the seal ring 47 is pressed against a rotating sliding surface 67 of the seal ring 45 attached to the other end side end portion of the rotor 35 by a spring 49. As a result, the seal ring 47 and the seat ring 45 seal the large-diameter hollow portion 61 where the first bearing 37 and the like are located and the internal space of the rotor 35, and steam or hot water passing through the rotor 35 or heated. Oil is prevented from entering the large-diameter hollow portion 61.

In order to lubricate the first bearing 37 and the second bearing 38, for example, lithium complex grease is used. The grease is filled in the space formed by the first bearing 37, the second bearing 38, the spacer 41 and the casing 33, and the first bearing 37 and the second bearing 38.
The grease fluidizes as the inner rings 73 and 74 of the first bearing 37 and the second bearing 38 and the spacer 41 rotate, and lubricates the first bearing 37 and the second bearing 38.
At this time, the grease fluidized in the space formed by the first bearing 37, the second bearing 38, the spacer 41 and the casing 33 flows along the inclined surface 85 and is supplied to the first bearing 37 or the second bearing 38. The

Thus, since the spacer 41 is formed at a middle height in the axial direction and both end portions in the axial direction with the smallest diameter are located outside the center position of the balls 71 and 72, the first bearing 37, the second The space formed by the two bearings 38, the spacer 41, and the casing 33 is significantly smaller than the conventional spacer.
When this space becomes small, the amount of grease staying here decreases, so the staying period becomes shorter. For this reason, it is possible to greatly reduce the possibility that the deterioration of the grease will progress to solidification.

Further, since the grease flows along the inclined surface 85, the fluidized grease can easily flow toward the bearing. As a result, the grease is less likely to be repeated between the fluidized state and the semi-solid state, so that the possibility of progress of deterioration and solidification can be further reduced.
Further, when the inclined surface 85 of the spacer 41 is coated with PTFE, it has good releasability from the grease, so that the retention of the grease is further reduced, and the deterioration of the grease may progress, leading to solidification. Further reduction can be achieved.

The fluidized grease flows out from the other end side of the second bearing 38. The leaked grease is guided by the guide surface 113 of the lubricating seal 51 and moves downward, and is discharged from the discharge portion 121 to the grease receiving tray 127.
Thus, since the grease is not retained by the lubricating sheet 51, it is possible to prevent deterioration and solidification in this portion.

In addition, the lubricating sheet 51 provided at the other end of the rotor 35 seals the grease flowing out from the second bearing 38 and discharges it to the outside of the system, so that the grease does not flow out toward the seal ring 47.
For this reason, since grease does not exist between the seal ring 47 and the seat ring 45, it is possible to prevent a situation where the grease is solidified and pressed to the other end side.
As a result, the seal between the seal ring 47 and the seat ring 45 is broken, and high temperature fluid can be prevented from flowing toward the second bearing 38.

The fluidized grease flows out from one end side of the first bearing 37.
Thus, the grease flowing out of the casing from the bearing on one end side is guided by the scraper 53 and the guide plate 125, moves downward, and is discharged to the grease receiving tray 127.
For this reason, since grease does not solidify outside the casing 33, the appearance is improved, and the situation where the first bearing 37 is locked can be prevented.

The selection of grease will be explained.
A heat resistance test was performed on the four types of heat resistant greases shown in Table 1. In the heat resistance test, the grease was maintained at 150 ° C., and the change in viscosity at that time was examined.

The results of the heat resistance test are shown in FIG. FIG. 9 shows the viscosity (1.5 × 10 ⁶ Pa · S) of the grease when an accident occurs in an actual machine for comparison.
From this, shell stamina RL2 is asymptotic to the viscosity at the time of the accident, and is determined to be incompatible.
For the other three types, the viscosity is one-tenth or less as compared with Shell Stamina RL2, and can be used sufficiently.
Among them, Multemp ET-100K has a lowest initial viscosity, but suddenly rises from the middle and has a problem in long-term use. This is presumed that the consistency (viscosity) changes due to oxidative deterioration and solidifies through curing, softening and curing processes.

In addition, NOXLUB is not as much as Multemp ET-100K, but the rate of increase in viscosity increases in the middle, and at about 2300 hours, the viscosity becomes larger than Daphne Eponex SR2, and the difference over time. Is getting bigger.
This is because fluorine used as a thickener has the property of easily evaporating the base oil, and it is presumed that the base oil evaporates and the viscosity increases with time due to this influence. Fluorine grease is expensive.
Therefore, from the viewpoint of long-term use, Daphne Eponex SR2 using lithium complex as a thickener was most preferable.

Lubricating performance was tested for Shell Stamina RL2, which was conventionally used in actual machines, and Daphne Eponex SR2, which had good heat test results. Two types of tests were performed, one using an SRV tester and the other using a high-speed four-ball tester.
In the SRV tester, a step load that increases the load by 50 N every 30 seconds was applied in an atmosphere of 80 ° C., and the seizure load was measured.
The high-speed four-ball type test machine measured the fusion load at a high speed of 1800 rpm in accordance with the actual machine.
The result is shown in FIG. From this, it was found that the seizure load of Daphne Eponex SR2 was about twice as large as that of Shell Stamina RL2, and the lubrication performance was also excellent.

Thus, the grease using a lithium complex as a thickener has a small increase in viscosity due to deterioration. When this grease is used for lubrication of the first bearing 37 and the second bearing 38, there is an allowance for the time until the grease deteriorates and solidifies, so that it is possible to prevent the grease from solidifying.
Further, the lubrication performance can be improved.

In the present embodiment, the spacer 41 has an integral structure, but the present invention is not limited to this. For example, as shown in FIG. 11, the spacer portion 129 and a grease supply portion 131 disposed outside the spacer portion. It may be divided into and.
The spacer portion 129 is made of metal, for example, steel, and defines the interval between the first bearing 37 and the second bearing 38.
The grease supply unit 131 reduces the space formed by the first bearing 37, the second bearing 38, the spacer 41, and the casing 33 and supplies grease to the first bearing 37 and the second bearing 38. The grease supply unit 131 is made of PTFE, for example, and improves the peelability from the grease.
In this way, since the spacer part 129 and the grease supply part 131 can be formed of appropriate shapes and materials, respectively, the degree of freedom in design can be improved.

[Second Embodiment]
Next, 2nd embodiment of this invention is described using FIGS. 12-14.
In this embodiment, the basic configuration is the same as that of the first embodiment, and the configuration of the spacer 41 is different. Therefore, in this embodiment, this difference is demonstrated and the overlapping description is abbreviate | omitted about another part.
In addition, the same code | symbol is attached | subjected to the component same as 1st embodiment, and the detailed description is abbreviate | omitted.

In the present embodiment, the spacer 41 includes a spacer part 133 and a grease supply part 135.
The spacer part 133 is a steel cylinder and firmly holds the space between the first bearing 37 and the second bearing 38.
The grease supply unit 135 is a PTFE cylinder, and is attached to the outer periphery of the spacer unit 133 with a gap. The grease supply unit 135 is held by the large diameter portion 55 so as not to rotate.
Since the outer diameter of the grease supply part 135 is substantially the same as the inner diameter of the large-diameter hollow part 61, the spacer 41 almost occupies the space between the first bearing 37 and the second bearing 38.

On the outer periphery of the grease supply unit 135, a lubricating groove 137 is provided at a substantially intermediate position in the axial direction so as to surround the periphery. The lubricating groove 137 is provided at a position corresponding to the grease nipple 87 and the opening 89 for attaching a member for discharging grease.
At the bottom of the lubricating groove 137, a plurality of, for example, six grease supply holes 139 facing inward are provided at substantially equal intervals in the circumferential direction.
A grease supply small hole 141 communicating with the first bearing 37 side or a grease supply small hole 143 communicating with the second bearing 38 side is provided at the bottom portion of the grease supply hole 139.
The grease supply small holes 141 and the grease supply small holes 143 are alternately provided in the circumferential direction.
The lubrication groove 137, the grease supply hole 139, and the grease supply small holes 141 and 143 constitute the flow path of the present invention.

Operation | movement of the rotary joint 1 concerning this embodiment comprised in this way is demonstrated.
About operation | movement of the rotary joint 1, since it is the same as that of 1st embodiment, the overlapping description is abbreviate | omitted and operation | movement of the spacer 41 is demonstrated.
Grease is supplied from the grease nipple 87 to the lubricating groove 137. This grease flows from the lubrication groove 137 to each grease supply hole 139.
Then, the grease is supplied from each grease supply hole 139 to the first bearing 37 or the second bearing 38 through the grease supply small hole 141 or the grease supply small hole 143.

Thus, the spacer 41 substantially occupies the space between the first bearing 37 and the second bearing 38, and the grease is in the lubrication groove 137, the grease supply hole 139 and the grease supply small holes 141, 143 of the grease supply part 135. It exists only in the part. Therefore, since the grease staying between the first bearing 37 and the second bearing 38 is further reduced as compared with the first embodiment described above, the grease staying period is shortened and the deterioration of the grease progresses. The possibility of reaching solidification can be further greatly reduced.
Since the other operations and effects are the same as those in the first embodiment described above, a duplicate description is omitted here.

1 is a perspective view showing an overall schematic configuration of an extruder according to a first embodiment of the present invention. It is a front view which shows the longitudinal stretcher concerning 1st embodiment of this invention. It is a perspective view which shows the attachment condition of the rotary joint concerning 1st embodiment of this invention. It is a longitudinal cross-sectional view which shows the whole schematic structure of the rotary joint concerning 1st embodiment of this invention. It is a perspective view which shows the assembly condition of the edge part structure of the rotor concerning 1st embodiment of this invention. It is a front view which shows the lubrication seal concerning 1st embodiment of this invention. It is XX sectional drawing of FIG. FIG. 6 is a YY view of FIG. 4. It is a graph which shows the result of the heat resistance test of grease. It is a graph which shows the result of the lubrication performance test of grease. It is sectional drawing which shows another embodiment of the spacer concerning 1st embodiment of this invention. It is a longitudinal cross-sectional view which shows the whole schematic structure of the rotary joint concerning 2nd embodiment of this invention. It is a front view which shows the grease supply part concerning 2nd embodiment of this invention. It is ZZ sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary joint 33 Casing 35 Rotor 37 First bearing 38 Second bearing 41 Spacer 43 Inner tube 45 Seat ring 47 Seal ring 49 Spring 51 Lubrication seal 53 Scraper 69, 70 Outer ring 71, 72 Ball 85 Inclined surface 113 Guide surface 129, 133 Spacer part 131, 135 Grease supply part 137 Lubrication groove 139 Grease supply hole 141, 143 Grease supply small hole

Claims (7)

A casing having an open space opened to one end side;
A tubular rotor having an end on the other end located in the open space and arranged to protrude from the casing;
A pair of bearings rotatably supporting the rotor with respect to the casing;
A spacer mounted between the pair of bearings and spaced between them;
A tubular inner tube attached to the casing so as to penetrate the inside of the rotor;
A seat ring attached to the other end of the rotor;
A seal ring that is attached to the other end side position of the rotor so as to be movable in the axial direction with respect to the casing, and that seals the open space and the interior of the rotor in cooperation with the seat ring;
A spring that presses and urges the seal ring toward the seat ring;
A rotary joint equipped with
The rotary joint is characterized in that an outer position of the spacer is positioned at least outside a center position of a rolling element of the bearing, and a flow path for supplying grease toward each of the bearings is provided.   2. The rotary joint according to claim 1, wherein the spacer has a middle-high shape in an axial direction, and an outer surface forms the flow path.   The rotary joint according to claim 1 or 2, wherein a portion of the spacer that contacts the grease is formed of a fluororesin.   The spacer includes a spacer portion that is disposed on the inside and defines a distance between the pair of bearings, and a grease supply portion that is disposed on the outside of the spacer portion and supplies the grease to the bearings. The rotary joint according to any one of claims 1 to 3, wherein the rotary joint is characterized.   The seal member configured to cover the periphery of the rotor is provided between the bearing on the other end side and the seal ring, according to any one of claims 1 to 4. Rotary joint.   The rotary joint according to claim 5, wherein the seal member includes a guide surface that guides grease to the rotor side. The rotary joint according to any one of claims 1 to 6, wherein the grease uses a lithium complex as a thickener.

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