JP4573230B2 - Rotary joint for fluid supply - Google Patents

Description

  The present invention relates to a rotary joint for supplying fluid, and more particularly, to a rotary joint that supplies fluid from the outside to a device such as an actuator that rotates with a rotary shaft.

  2. Description of the Related Art Conventionally, a technique is known in which a chuck device including an actuator driven by a fluid (for example, air) is disposed on a rotating main shaft, and fluid is supplied from outside to open and close the claws of the chuck device.

  The flow path for supplying fluid to the actuator is provided so as to extend to the actuator through a housing that supports the main shaft and a rotating main shaft from a fluid supply device arranged outside. Here, a rotary joint using a contact seal or a rotary joint using a non-contact seal such as a labyrinth seal is provided between the non-rotating housing and the rotating main shaft, and fluid flows from the housing into the main shaft. The leakage at the time is prevented (for example, refer to Patent Document 1 or 2).

Japanese Patent Laid-Open No. 5-296376 (page 3, FIG. 1, etc.) Japanese Utility Model Publication No. 5-88809 (page 5-6, FIG. 1 etc.)

In the above-mentioned patent document 1, a rotary joint that rotatably supports a rotary shaft on a joint body by a bearing and an air bearing portion, and a non-contact seal is formed by supplying air from the outside to the air bearing portion. Technology is disclosed.
According to this technique, the air supplied to the air bearing can reduce the leakage of the fluid supplied from the joint body to the rotating shaft in the air bearing. Further, since it is a non-contact seal, the rotating shaft can be rotated at a higher speed and the rotation accuracy can be easily increased as compared with the contact seal.

However, in the rotary joint using the non-contact seal disclosed in the above-mentioned Patent Document 1 or the like, a gap is always formed between the joint body that does not rotate and the rotary shaft that rotates. When the gap is formed, it is difficult to prevent the leakage even though the fluid leakage from the gap can be reduced.
In addition, non-contact seals such as labyrinth seals are likely to increase in size in order to reduce fluid leakage, and thus there is a problem that it is difficult to reduce the size of the joint.

In addition to the method of reducing fluid leakage from the rotary joint, a method of increasing the fluid supply pressure so as to compensate for the fluid leakage is also known.
However, since there is an upper limit to the pressure of the fluid supplied at the factory, there is a problem that it is insufficient to compensate for the above-described reduction in thrust.
In addition, raising the upper limit of the pressure of the supply fluid in the factory has a problem that it cannot be easily performed because it takes a lot of cost and time, such as replacing the pipes arranged in the whole factory with high-strength pipes. It was.

In the above-mentioned Patent Document 2, rotation using a contact seal that has a seal that contacts a rotating main shaft and supplies fluid to the main shaft and that blows air mixed with mist of lubricating oil on the seal in the vicinity. Joint technology is disclosed.
According to this technique, lubricating oil can always be supplied to the sliding surface between the main shaft and the seal. In particular, even when the main shaft is rotated and the lubricating oil is blown from the sliding surface by centrifugal force, the lubricating oil is supplied to the sliding surface. Therefore, it was possible to prevent the seal from being worn out due to running out of the lubricating oil and to maintain the sealing performance for a long time.

  However, in the rotary joint using the contact seal disclosed in Patent Document 2 and the like, frictional heat is generated on the sliding surface between the main shaft and the seal. In particular, when the main shaft is rotated at a high speed, there is a problem that the sliding surface becomes high temperature due to frictional heat, and the sealing performance and durability are lowered.

Further, when an angular bearing is used for supporting the main shaft, a method of supplying a fluid from a housing supporting the main shaft to the main shaft by providing a fluid flow path in a preload spacer of the angular bearing is also known.
In such a case, a non-contact seal type angular bearing is used in order to avoid generation of heat due to sliding friction during high-speed rotation of the main shaft. Furthermore, in order to minimize the fluid leakage from the spacer between the inner and outer rings, the one with the gap narrowed as much as possible is used.
However, even when the above-described method is used, there is a problem in that fluid leakage from an angular bearing or the like occurs and a predetermined fluid supply amount and supply pressure may not be obtained.

  The present invention has been made to solve the above problems, and provides a rotary joint for fluid supply capable of improving hermeticity and capable of supporting high-speed rotation and reducing the installation space. The purpose is to do.

In order to achieve the above object, the present invention provides the following means.
The present invention is arranged between two bearings that support the outer member and the inner member in a relatively rotatable manner, is fixed to the outer member, and is sandwiched between outer rings of the bearings, and the inner member. An inner ring spacer member that is fixed and disposed between the inner rings of the bearings and is disposed with a gap in the radial direction with respect to the outer ring spacer member, and is sandwiched between the inner ring spacer member and the inner ring of the bearing A ring plate-like seal member having a flexible outer peripheral portion disposed with a gap in the axial direction with respect to the outer ring of the bearing, and the inner ring spacer member and the outer ring spacer member, Provided is a rotary joint for fluid supply provided with a flow path through which a fluid passes through in a radial direction.

  According to the present invention, the inner ring spacer is disposed with a gap in the radial direction with respect to the outer ring spacer, and a gap is formed between the outer peripheral portion of the seal member and the outer ring. Therefore, when a fluid of a predetermined pressure is not supplied to the flow path, sliding between the inner ring spacer and the outer ring spacer and the seal member and the outer ring due to relative rotation between the outer member and the inner member is prevented, and sliding is prevented. Heat generation due to movement can be prevented. As a result, it is possible to cope with high-speed relative rotation between the outer member and the inner member.

For example, when the outer member is fixed and the inner member is rotated, the seal member is sandwiched between the inner ring and the inner ring spacer, and thus rotates with the rotation of the inner member. In such a case, since the outer peripheral portion of the seal member extends radially outward due to centrifugal force, a gap is formed between the outer ring and the outer ring. Further, since the fluid in the vicinity of the seal member rotates together with the seal member due to its viscosity, a gap is formed between the outer peripheral portion of the seal member and the outer ring by the pressure of the rotating fluid.
Therefore, sliding between the seal member and the outer ring and sliding between the outer ring spacer and the inner ring spacer does not occur, and it is possible to cope with high-speed relative rotation between the outer member and the inner member.

When a fluid of a predetermined pressure is supplied to the flow path, the outer peripheral portion of the seal member comes into contact with the outer ring or the gap with the outer ring becomes narrow, so that the sealing performance of the fluid supply rotary joint can be improved.
Specifically, when a fluid of a predetermined pressure is supplied to the flow path, most of the fluid flows between the outer member and the inner member through the flow path, and the remaining fluid flows between the outer ring spacer and the inner ring. It flows into the gap between the seat. The fluid flowing into the gap tends to flow out from between the outer ring and the inner ring of the bearing. At this time, the fluid pushes the outer peripheral portion of the seal member toward the outer ring, and the outer peripheral portion contacts the outer ring or the gap between the outer ring and the outer ring becomes narrow. When the outer peripheral portion and the outer ring come into contact with each other, the space between the outer ring spacer and the inner ring spacer is completely sealed, and the fluid supply rotary joint is sealed. Further, when the gap between the outer peripheral portion and the outer ring becomes narrow, it becomes difficult for fluid to flow out between the outer ring spacer and the inner ring spacer, and the sealing performance of the fluid supply rotary joint is improved.

  Since the rotary joint for fluid supply of the present invention is composed of an outer ring spacer, an inner ring spacer, and a seal member arranged between two bearings, a dedicated space for providing a rotary joint as in the prior art is provided. It can arrange | position without providing and an installation space can be made small.

  In the above invention, the axial length of the outer ring spacer is formed to be longer than the axial length of the inner ring spacer, and the outer ring spacer faces the outer ring. It is desirable that a stepped portion that is recessed toward the flow path toward the inner ring spacer is provided.

According to the present invention, since the axial length of the outer ring spacer is longer than the axial length of the inner ring spacer, the distance between the outer rings sandwiching the outer ring spacer is larger than the distance between the inner rings sandwiching the inner ring spacer. Become wider. Therefore, a gap can be formed between the outer peripheral portion of the seal member sandwiched between the inner ring and the inner ring spacer and the outer ring.
Since the stepped portion is provided on the facing surface of the outer ring spacer, a gap can be formed between the outer peripheral portion of the seal member and the outer ring spacer.

In the above invention, the enlarged portion where the gap between the inner ring spacer and the outer ring spacer is widened between the flow path and the bearing in at least one of the inner ring spacer or the outer ring spacer. It is desirable to be provided.
According to the present invention, since at least one of the inner ring spacer and the outer ring spacer is provided with the enlarged portion that widens the gap, the fluid flowing through the gap from the flow path toward the bearing is stopped by the enlarged portion. Can do.

In the said invention, it is desirable that the said sealing member is a film | membrane formed from resin.
According to the present invention, since the seal member is formed of a resin having a relatively small friction coefficient, even if the seal member and the outer ring come into contact with each other while the outer member and the inner member are rotating relative to each other, the slide member slides. It is difficult to generate heat due to. Further, since the sealing member is a resinous film, the sealing member is highly flexible, and the sealing member can be brought into contact with the outer ring even with a slight pressure.

  The present invention is arranged between two bearings that support the outer member and the inner member in a relatively rotatable manner, is fixed to the outer member, and is sandwiched between outer rings of the bearings, and the inner member. An inner ring spacer member that is fixed and disposed between the inner rings of the bearings and is disposed with a gap in the radial direction with respect to the outer ring spacer member, and is sandwiched between the outer ring spacer member and the outer ring of the bearing A ring plate-like seal member having a flexibility, the inner peripheral portion being arranged with a gap in the axial direction with respect to the inner ring of the bearing, and the inner ring spacer member and the outer ring spacer member Provided are fluid supply rotary joints each provided with a flow path through which a fluid passes through in the radial direction.

  According to the present invention, the inner ring spacer is disposed with a gap in the radial direction with respect to the outer ring spacer, and a gap is formed between the outer peripheral portion of the seal member and the outer ring. When fluid of a predetermined pressure is not supplied to the flow path, sliding between the inner ring spacer and the outer ring spacer and the seal member and the inner ring due to relative rotation between the outer member and the inner member is prevented. Heat generation due to movement can be prevented. As a result, it is possible to cope with high-speed relative rotation between the outer member and the inner member.

  When a fluid of a predetermined pressure is supplied to the flow path, the inner peripheral portion of the seal member comes into contact with the inner ring or the gap with the inner ring becomes narrow, so that the sealing performance of the fluid supply rotary joint can be improved. .

  Since the rotary joint for fluid supply of the present invention is composed of an outer ring spacer, an inner ring spacer, and a seal member arranged between two bearings, a dedicated space for providing a rotary joint as in the prior art is provided. It can arrange | position without providing and an installation space can be made small.

  According to the fluid supply rotary joint of the present invention, the inner ring spacer is disposed with a gap in the radial direction with respect to the outer ring spacer, and a gap is formed between the outer peripheral portion of the seal member and the outer ring. The sliding between the inner ring spacer and the outer ring spacer and the seal member and the outer ring due to the relative rotation between the outer member and the inner member is prevented. As a result, it is possible to prevent the generation of heat due to sliding, and it is possible to cope with high-speed relative rotation between the outer member and the inner member.

  When a fluid of a predetermined pressure is supplied to the flow path, the outer peripheral portion of the seal member comes into contact with the outer ring or the gap with the outer ring becomes narrow, so that the sealing performance of the fluid supply rotary joint can be improved. There is an effect.

  Since the rotary joint for fluid supply of the present invention is composed of an outer ring spacer, an inner ring spacer, and a seal member arranged between two bearings, a dedicated space for providing a rotary joint as in the prior art is provided. It can arrange | position without providing and there exists an effect that an installation space can be made small.

A rotary joint according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram illustrating an overall configuration of a chuck device provided with a rotary joint according to the present embodiment.
As shown in FIG. 1, the rotary joint (rotary joint for fluid supply) 1 is used in a chuck device 9 in which a gripping mechanism 7 is provided at an end portion of a spindle 5 of the spindle unit 3.
The main shaft unit 3 includes a bottomed cylindrical housing (outer member) 11, a main shaft (inner member) 5 disposed in the housing 11, and a motor 13 disposed between the housing 11 and the main shaft 5. And the rotary joint 1 and the support bearing 15 that rotatably support the main shaft 5 around the central axis C.
The gripping mechanism 7 is generally configured by a cylinder portion 17 driven by a supply air AR supplied from the outside and a diaphragm chuck portion 19 driven by the cylinder portion 17.

2 is a cross-sectional view taken along the line AA in the chuck device of FIG. 3 is a cross-sectional view taken along line EE in FIG.
As shown in FIGS. 2 and 3, the housing 11 includes a supply joint 21 that distributes supply air (fluid) AR having a predetermined pressure between the outside and the rotary joint 1, and a housing flow path 23. Is provided.
As shown in FIG. 1, the main shaft 5 is formed with a main shaft flow path 25 through which the supply air AR is circulated between the rotary joint 1 and the cylinder portion 17, and is fixed to fix an inner ring of a joint bearing described later to the main shaft 5. A nut 27 is provided.

As shown in FIGS. 1 to 3, the rotary joint 1 includes two joint bearings (bearings) 29, 29, an outer ring spacer 31 disposed between the joint bearings 29, 29, an inner ring spacer 33, A sealing seal (seal member) 35 is generally configured.
The joint bearing 29 is schematically composed of an outer ring 37 disposed in contact with the housing 11, an inner ring 39 disposed so as to rotate together with the main shaft 5, and a ball 41 that rolls between the outer ring 37 and the inner ring 39. Has been. The outer ring 37 and the inner ring 39 are formed with tracks on which the balls 41 roll. The raceway is formed in a shape that allows the joint bearing 29 to receive a radial load (radial load) and a load (axial load) in at least one direction in the central axis C direction (axial direction).
An example of the joint bearing 29 is an angular bearing, but other bearings may be used.

  The two joint bearings 29 are arranged so that the axial loads that can be received are in opposite directions. In the present embodiment, the joint bearing is arranged so that the axial load that can be received by the joint bearing 29 is directed outward from the outer ring spacer 31 and the inner ring spacer 33.

FIG. 4 is a partially enlarged view for explaining a main part of the rotary joint of FIG.
As shown in FIGS. 3 and 4, the outer ring spacer 31 is disposed in contact with the housing 11 and sandwiched between the outer rings 37 of the joint bearing 29.
An annular outer groove (flow path) 43 is formed on the outer peripheral surface of the outer ring spacer 31, and outer supply holes (flow paths) 45 extending in the radial direction are formed at three to four locations on the bottom surface of the outer groove 43. ing. The outer groove 43 is disposed so as to communicate with the housing flow path 23 of the housing 11. On the surface of the outer ring spacer 31 facing the outer ring 37, an outer stepped portion (stepped portion) 47 is formed that is recessed toward the outer supply hole 45 toward the inside in the radial direction.

The inner ring spacer 33 is in contact with the main shaft 5 and is disposed between the inner rings 39 of the joint bearing 29.
An annular middle groove (flow path) 49 and an inner groove (flow path) 51 are formed on the outer peripheral surface and the inner peripheral surface of the inner ring spacer 33, respectively. On the bottom surfaces of the middle groove 49 and the inner groove 51, inner supply holes (flow paths) 53 that allow the grooves 49 and 51 to communicate with each other are formed to extend in three to four locations in the radial direction. The middle groove 49 is arranged to face the opening of the outer supply hole 45 of the outer ring spacer 31, and the inner groove 51 is arranged to communicate with the main shaft flow path 25 of the main shaft 5.
On the surface of the inner ring spacer 33 that faces the inner ring 39, an inner stepped portion 55 that is recessed toward the inner supply hole 53 toward the outer side in the radial direction is formed.

  The outer supply hole 45 and the inner supply hole 53 described above may be formed in three to four places as described above, or may be formed in more places than three to four places. It may be formed in less than 3 to 4 places and is not particularly limited.

The width (length) Lo of the outer ring spacer 31 in the central axis C direction is formed wider (longer) than the width (length) Li of the inner ring spacer 33 in the central axis C direction.
Further, in the outer ring spacer 31 and the inner ring spacer 33, a clearance (gap) having a predetermined interval (for example, several tens of μm) is formed between the inner peripheral surface of the outer ring spacer 31 and the outer peripheral surface of the inner ring spacer 33. Are arranged as follows.
A buffer groove (enlarged portion) 57 that is an annular groove that widens the predetermined interval is formed on the inner peripheral surface of the inner ring spacer 33. The buffer groove 57 is formed between the middle groove 49 and the surface of the inner ring spacer 33 with respect to the joint bearing, and forms a so-called labyrinth seal.

As shown in FIGS. 3 and 4, a sealing seal 35 made of polytetrafluoroethylene (Teflon (registered trademark)) is disposed between the inner ring 39 and the inner ring spacer 33. The sealing seal 35 is a film member formed in a substantially ring plate shape. The outer peripheral portion of the sealing seal 35 extends to the vicinity of the inner side of the outer stepped portion 47 of the outer ring spacer 31, and the outer peripheral portion is formed to be in contact with the outer ring 37 by bending.
In addition, as a film thickness of the sealing seal 35, although about 0.3 mm can be illustrated, it is not limited to this film thickness.
Further, the sealing seal 35 may be formed of polytetrafluoroethylene as described above, or other resin having a small friction coefficient may be used.
Between the outer ring 37 and the outer ring spacer 31, an adjustment seal 36 having substantially the same film thickness as the sealing seal 35 is disposed.

A gap CL having a predetermined width is formed between the outer peripheral portion of the sealing seal 35 and the outer ring 37. The width of the gap CL is adjusted by the difference between the width Lo of the outer ring spacer 31 and the width Li of the inner ring spacer 33.
Further, the inner rings 39, 39 and the outer rings 37, 37 are tightened in the direction of the central axis C, and the joint bearing 29 is preloaded by the fixed position pressurization method due to the difference in width between the outer ring spacer 31 and the inner ring spacer 33. ing.

Next, the operation of the chuck device 9 having the above configuration will be described.
As shown in FIG. 1, the chuck device 9 is supplied with supply air AR from the outside to the cylinder portion 17 via the rotary joint 1 in a state where the main shaft 5 is stopped. When air is supplied to the cylinder part 17, the diaphragm chuck part 19 opens, and the workpiece W can be attached and detached.
After that, when the air supplied to the cylinder portion 17 is caused to flow outside through the rotary joint 1, the diaphragm chuck portion 19 is closed and the workpiece W is gripped. In this state, the main shaft 5 is rotated to process the workpiece W, for example.

Next, the operation of the rotary joint 1 which is a characteristic part of the present invention will be described.
First, an operation when supply air of a predetermined pressure flows into the rotary joint 1 will be described.
First, the supply air AR is supplied from the outside to the rotary joint 1 through the supply joint 21 and the housing flow path 23 as shown in FIG.
As shown in FIGS. 3 and 4, the supply air AR flows into the outer groove 43 of the outer ring spacer 31 and flows in the outer supply hole 45 toward the inner ring spacer 33. Most of the supply air AR that flows out of the outer supply hole 45 flows into the inner groove 49 of the inner ring spacer 33 and flows into the inner supply hole 53 and the inner groove 51. The supply air AR that has flowed into the inner groove 51 flows into the main shaft flow path 25 of the main shaft 5.

On the other hand, the remainder of the supply air AR that has flowed out of the outer supply hole 45 flows into the clearance between the outer ring spacer 31 and the inner ring spacer 33. The supply air AR that has flowed into the clearance flows in the direction of the joint bearing 29, flows into the buffer groove 57, and is blocked by the buffer groove 57.
The supply air AR that has further flowed out toward the joint bearing 29 beyond the buffer groove 57 tends to flow into the space between the outer ring 37 and the inner ring 39 through the clearance CL between the sealing seal 35 and the outer ring 37. At this time, since the supply air AR presses the sealing seal 35 in the direction of the outer ring 37, the sealing seal 35 bends in the direction of the outer ring 37, and the outer peripheral portion of the sealing seal 35 contacts the outer ring 37.

  Thereafter, since the pressure of the supply air AR acts on the sealing seal 35, the outer peripheral portion of the sealing seal 35 and the outer ring 37 are in close contact with each other. When the supply air AR is supplied to the rotary joint 1, since the main shaft 5 is not rotating as described above, no sliding occurs between the sealing seal 35 and the outer ring 37. No heat is generated.

Next, the operation of the rotary joint 1 when the main shaft 5 is rotating will be described.
When the main shaft 5 rotates, as shown in FIGS. 3 and 4, the inner ring 39, the inner ring spacer 33, and the sealing seal 35 rotate together with the main shaft.
When the sealing seal 35 rotates, a centrifugal force acts on the sealing seal 35, so that the outer peripheral portion extends straight outward in the radial direction. Therefore, a gap is formed between the outer peripheral portion of the sealing seal 35 and the outer ring 37 and the outer ring spacer 31.
Further, the air in the vicinity of the sealing seal 35 rotates together with the sealing seal 35 due to its viscosity, so that the pressure of the rotating air causes the air between the outer periphery of the sealing seal 35 and the outer ring 37 and the outer ring spacer 31. A gap is formed.

  Since the sealing seal 35 is not in contact with the outer ring 37 and the outer ring spacer 31, even if the sealing seal 35 rotates, the outer ring 37 and the outer ring spacer 31 do not slide and no sliding heat is generated. Since the supply air AR is not supplied to the rotary joint 1 when the main shaft 5 is rotated, the sealing seal 35 is not pressed toward the outer ring 37 and does not come into contact with the outer ring 37.

  According to the above configuration, a clearance of a predetermined interval is provided between the inner ring spacer 33 and the outer ring spacer 31, and a gap is provided between the outer peripheral portion of the sealing seal 35 and the outer ring 37 and the outer ring spacer 31. Is formed. Therefore, when the supply air AR is not supplied to the rotary joint 1, sliding between the sealing seal 35, the outer ring 37 and the outer ring spacer 31 due to rotation of the main shaft 5 is prevented, and heat is generated by sliding. Can be prevented. As a result, it is possible to cope with high-speed rotation of the main shaft 5.

  When the supply air AR is supplied to the rotary joint 1, the outer peripheral portion of the sealing seal 35 is pressed by the supply air AR and comes into contact with the adjacent outer ring 37, or the gap between the adjacent outer rings 37 is narrowed. The sealing performance of the rotary joint 1 can be improved.

  Since the rotary joint 1 is composed of the outer ring spacer 31, the inner ring spacer 33, and the sealing seal 35 disposed between the joint bearings 29, a dedicated space for providing the rotary joint is provided as in the prior art. Can be arranged without any problem, and the installation space can be reduced.

Since the width Lo of the outer ring spacer 31 in the direction of the central axis C is wider than the width Li of the inner ring spacer 33 in the direction of the central axis C, the outer ring 37 that sandwiches the outer ring spacer 31 more than the interval between the inner rings 39 that sandwich the inner ring spacer 33. The interval of becomes wider. Therefore, when the outer peripheral portion of the sealing seal 35 sandwiched between the inner ring 39 and the inner ring spacer 33 extends radially outward, a gap can be formed between the outer peripheral portion and the outer ring 37.
Further, since the outer stepped portion 47 is provided on the surface of the outer ring spacer 31 facing the outer ring 37, when the outer peripheral portion of the sealing seal 35 extends radially outward, the outer peripheral portion and the outer ring spacer are arranged. A gap can be formed between the gaps 31 and 31.

  Since the buffer groove 57 that widens the predetermined clearance is provided on the inner peripheral surface of the inner ring spacer 33, the clearance between the outer ring spacer 31 and the inner ring spacer 33 is changed from the outer supply hole 45 to the joint bearing 29. The supply air AR flowing toward the

Since the sealing seal 35 is made of polytetrafluoroethylene having a small friction coefficient, heat is generated by sliding even if the sealing seal 35 and the outer ring 37 come into contact with each other while the main shaft 5 is rotating. It becomes difficult to do. Further, since the sealing seal 35 is a polytetrafluoroethylene film, the sealing seal 35 and the outer ring 37 can be brought into contact with each other even with a slight pressure.
In addition, since the polytetrafluoroethylene film can be obtained at a very low cost, the rotary joint 1 of the present invention can be manufactured at a low cost.

As described above, the supply air AR may be supplied to the rotary joint 1 with the main shaft 5 stopped, or the supply air AR may be supplied to the rotary joint 1 with the main shaft 5 rotated. . At this time, the rotational speed of the main shaft 5 is preferably lower than the rotational speed when machining the workpiece.
In this case, since the pressing force by the supply air AR acts on the sealing seal 35, the gap CL between the sealing seal 35 and the outer ring 37 is narrower than in the case where no air is supplied. On the other hand, the sealing seal 35 does not come into contact with the outer ring 37 due to the centrifugal force acting by the rotation of the sealing seal 35 and the air rotating in the vicinity of the sealing seal 35 with the sealing seal 35 due to viscosity.

  As described above, the width Lo of the outer ring spacer 31 may be formed wider than the width Li of the inner ring spacer 33 to form a gap between the sealing seal 35 and the outer ring 37, or the outer ring spacer The width Lo of 31 and the width Li of the inner ring spacer 33 are substantially the same, or the width Lo is formed narrower than the width Li, and a step portion is formed in the outer ring 37 so that the seal 35 and the outer ring 37 A gap may be formed.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the rotary joint of the present invention has been applied to the chuck device. However, the present invention is not limited to the chuck device, and is applicable to all other devices that supply fluid into the rotary shaft from the outside. Is something that can be done.

  In the above embodiment, the case where the casing fixed on the outside is disposed and the main shaft that rotates on the inside is disposed has been described. However, the present invention is not limited to this configuration. It can also be applied to a rotary joint when a rotating casing is arranged and a shaft fixed inside is arranged.

  Furthermore, in the above embodiment, the description has been made by applying the present invention to a rotary joint having a configuration in which a seal member is sandwiched between the inner ring spacer and the inner ring. The present invention can also be applied to a rotary joint having a configuration in which a seal member is sandwiched between them.

It is a figure explaining the whole structure of the chuck device provided with the rotation joint concerning one embodiment of the present invention. It is AA sectional view in the chuck device of FIG. It is the EE sectional view in FIG. It is the elements on larger scale explaining the principal part of the rotary joint of FIG.

Explanation of symbols

1 Rotary joint (rotary joint for fluid supply)
5 Main shaft (inner member)
11 Housing (outside member)
29 Joint bearing (bearing)
31 Outer ring spacer 33 Inner ring spacer 35 Seal for sealing (seal member)
43 Outer groove (flow path)
45 Outer supply hole (flow path)
47 Outside step (step)
49 Middle groove (flow path)
51 Inner groove (flow path)
53 Inside supply hole (flow path)
57 Buffer groove (enlarged part)
AR supply air (fluid)
CL gap

Claims (5)

Disposed between two bearings that support the outer member and the inner member in a relatively rotatable manner;
An outer ring spacer member fixed to the outer member and sandwiched between outer rings of the bearings;
An inner ring spacer member fixed to the inner member, disposed between the inner rings of the bearing, and disposed with a gap in the radial direction with respect to the outer ring spacer member;
A ring-plate-shaped sealing member having flexibility, which is sandwiched between the inner ring spacer member and the inner ring of the bearing, and whose outer peripheral portion is disposed with a gap in the axial direction with respect to the outer ring of the bearing. Have
Fluid supply rotary joints, wherein the inner ring spacer member and the outer ring spacer member are each provided with a flow path through which fluid flows in the radial direction. The axial length of the outer ring spacer is formed longer than the axial length of the inner ring spacer,
The rotary joint for fluid supply according to claim 1, wherein a stepped portion that is recessed toward the flow path toward the inner ring spacer is provided on a surface of the outer ring spacer facing the outer ring.   Between the flow path and the bearing in at least one of the inner ring spacer or the outer ring spacer, there is provided an enlarged portion that widens the gap between the inner ring spacer and the outer ring spacer. The rotary joint for fluid supply according to claim 1 or 2.   The rotary joint for fluid supply according to claim 1, wherein the seal member is a film made of resin. Arranged between two bearings for supporting the outer member and the inner member in a relatively rotatable manner,
An outer ring spacer member fixed to the outer member and sandwiched between outer rings of the bearings;
An inner ring spacer member fixed to the inner member, disposed between the inner rings of the bearing, and disposed with a gap in the radial direction with respect to the outer ring spacer member;
A ring-plate-shaped sealing member having flexibility, which is sandwiched between the outer ring spacer member and the outer ring of the bearing, and has an inner peripheral portion disposed with a gap in the axial direction with respect to the inner ring of the bearing; Have
Fluid supply rotary joints, wherein the inner ring spacer member and the outer ring spacer member are each provided with a flow path through which fluid flows in the radial direction.

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