JP3263529B2 - Fluid supply fitting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid supply coupling for guiding fluid to a high-speed rotating shaft such as a main shaft of a machine tool.

[0002]

2. Description of the Related Art A conventional fluid supply coupling is disclosed in Japanese Unexamined Utility Model Publication No.
No. 941 discloses a non-contact type rotary joint. This rotary joint is, as shown in FIG.
11 and a bearing 116.
A small gap 114 is provided between the rotary joint shaft 113 and the rotary joint shaft 113 to prevent the rotary joint shaft 113 from coming into contact with the rotary joint shaft 113. Sealing of cutting oil or the like passing through the oil hole 115 is performed by the small gap 114. Then, high-pressure fluid from the outside is guided through a fluid supply hole 117 formed in the rear lid 112, and the rotary joint shaft 11
The fluid is supplied to a fluid supply passage 120 formed at the center of a main shaft 119 supported by a bearing (not shown) via a supply passage 118 formed at the center of the shaft 3.

[0003]

However, when the pressure of the supply fluid becomes high, the amount of fluid leaking from the minute gap 114 becomes excessive, and the leaked fluid fills the bearings 116 and the like, and the bearings 116 and the like break down. There was a problem. In addition, there is a problem that since the fluid leaking from the gap is not treated at all, it cannot be used when the supply fluid is not an oil such as a cutting oil but a water-soluble working fluid or pure water.

Further, since the rotating shaft supported by the bearing and the joint shaft supported by the bearing are coaxially connected, problems of vibration and heat generation of the bearing occur, and the rotation speed is limited by the bearing. The problem arises.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to supply a fluid at a high pressure regardless of the kind of the supplied fluid, and to provide no limitation on the number of rotations, vibration, heat, and the like. An object of the present invention is to provide a fluid supply coupling that does not cause any problems.

[0006]

In order to achieve this object, a fluid supply joint according to the present invention is mounted coaxially with a rotating shaft, is integrally rotated, and is connected to the rotating shaft along the axis from its outer end face. A joint shaft having a fluid passage extending toward the joint shaft, a concave portion for holding the joint shaft in a non-contact and close state with respect to a peripheral side surface and an outer end surface thereof are formed, and a fluid on an outer end surface of the joint shaft is formed. A joint body in which a fluid outlet is formed on the bottom surface of the concave portion facing the passage opening, a fluid resistance path defined between the outer end surface of the joint shaft and the bottom surface of the concave portion of the joint body, and a joint shaft. A pump chamber is formed by the formed dynamic pressure generating groove and the concave portion of the joint body, and returns the fluid to the fluid resistance path according to the rotation of the joint shaft.

[0007]

Further, a leaked fluid pressure drop chamber formed on the side surface of the concave portion of the joint body so as to communicate with the pump chamber, and the leaked fluid pressure drop chamber opened to the leaked fluid pressure drop chamber, and the leaked fluid having reduced pressure is supplied to the outside of the joint body. And a drain hole for discharging to the drain hole.

Further, a flange provided on the joint body so as to have a minute gap between the joint shaft and the compressed air for supplying compressed air to the leaking fluid pressure drop chamber from the minute gap. A supply passage may be further provided.

[0010]

In the fluid supply joint of the present invention having the above-described structure, the joint shaft is attached coaxially with the rotation shaft, is integrally rotated, and extends from the outer end surface thereof along the axis toward the rotation shaft. A fluid passage is formed, the joint body is formed with a concave portion for holding the joint shaft in a non-contact and close state with respect to a peripheral side surface and an outer end surface thereof, and a fluid passage opening at an outer end surface of the joint shaft. A fluid outlet is formed on the bottom surface of the concave portion facing the fluid passage, the fluid resistance path is defined between the outer end surface of the joint shaft and the bottom surface of the concave portion of the joint body, and the dynamic pressure generating groove is formed on the joint shaft. The pump chamber is formed by the dynamic pressure generating groove and the concave portion of the joint body, and returns the fluid to the fluid resistance path according to the rotation of the joint shaft.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the fluid supply joint of the present invention. In FIG. 1, a rotating shaft 1 such as a main shaft of a machine tool is rotatably supported by a housing 5 via a bearing 3. The rotating shaft 1 is provided with a fluid passage 7 at the shaft center, and a joint shaft 9 is fastened to an end of the rotating shaft 1 by a bolt 11, and rotates integrally with the rotating shaft 1. The joint shaft 9 is provided with a rotation-side fluid passage 13 at the axis thereof, and communicates with the fluid passage 7.

A joint body 15 is fitted and fixed to the right end of the housing 5 in FIG.
A fluid supply hole 19 is formed at the center of the right end face of the joint body 15, and a joint body-side fluid passage 21 communicating with the fluid supply hole 19 is opened at a bottom surface of the concave portion of the joint body 15 via a spout 21 a.

The joint shaft 9 is inserted into the concave portion 16 of the joint main body 15, and a fluid passage opening 13 a of the rotation-side fluid passage 13 is provided so as to face the ejection port 21 a of the joint main body-side fluid passage 21. The joint body side fluid passage 21 and the rotation side fluid passage 13 communicate with each other so that fluid can be supplied to the joint shaft 9.

A fluid resistance path 23 is formed by maintaining a small gap between the convex portion provided at the center of the bottom surface of the concave portion of the joint body 15 and the concave portion provided on the outer end surface 9a of the joint shaft 9.

As shown in FIG. 2, a plurality of spiral dynamic pressure generating grooves 25 are formed on the outer peripheral surface of the right end of the joint shaft 9.
The projection forms a pump chamber 27 that generates a dynamic pressure effect while maintaining a small gap with the joint body 15.

An annular recess 29 is formed in the joint body 15 adjacent to the pump chamber 27. The annular recess 29 constitutes a leakage fluid pressure drop chamber 31 together with the outer peripheral surface of the joint shaft 9, and a drain hole 33 opening in the peripheral surface of the annular concave 29 is formed in the joint main body 15.

A ring-shaped flange 35 is disposed adjacent to the annular recess 29 of the joint body 15 and is fixed to the joint body 15 by bolts 37. The flange 35 and the joint body 15 are sealed by an O-ring 39.
The inner peripheral surface of the flange 35 and the outer peripheral surface of the joint shaft 9 are kept out of contact with each other while maintaining a small gap 41.

An annular groove 43 is formed on the inner peripheral surface of the flange 35, and a compressed air supply passage 45 communicating with the groove 43.
Are formed on the flange 35.

On the other hand, a joint body compressed air supply passage 47 communicating with the compressed air supply passage 45 is formed in the joint body 15, and a compression end communicating with the joint body compressed air supply passage 47 is formed at the right end of the joint body 15. An air supply hole 49 is open. O is provided at the contact portion between the joint body 15 and the flange 35.
The ring 51 is inserted to prevent the compressed air from leaking.
Compressed air supply hole 49, joint body compressed air supply passage 47,
The compressed air supply passage 45 and the annular groove 43 are
1 constitutes an air passage for supplying compressed air.

The joint body 15 is provided with an exhaust port 53.

The operation based on the above configuration will be described.

A fluid such as a high-pressure coolant is supplied to the joint body 15.
Is supplied from the fluid supply hole 19 on the end face. When supplying the fluid, compressed air is simultaneously supplied from the compressed air supply hole 49 on the end face of the joint body 15. The fluid is the fluid passage 2 on the joint body side.
1 is supplied into the fluid passage 7 of the rotating shaft 1 via a rotating fluid passage 13 provided in the joint shaft 9 that rotates at a high speed. A part of the fluid flows from the bottom of the concave portion of the joint body 15 to the joint shaft 9.
And leaks into the pump chamber 27 from the fluid resistance path 23 formed between the two. In the fluid, a dynamic pressure effect is generated by the pump action of the plurality of spiral dynamic pressure generating grooves 25 provided on the outer peripheral surface of the joint shaft 9 rotating at a high speed, and most of the fluid is returned to the fluid resistance path 23.

A small part of the fluid leaks from the pump chamber 27 and blows out to the leaked fluid pressure drop chamber 31. When the fluid passes through the fluid resistance path 23 and the pump chamber 27, the pressure drops, and the cross-sectional area of the leaked fluid pressure drop chamber 31 is
The pressure drop is generated because the pressure is sufficiently large compared to the minute gap of the pump chamber 27, and the pressure of the fluid filling the leaked fluid pressure drop chamber 31 is higher than the fluid pressure in the joint body side passage 21 and the rotation side fluid passage 13. It drops significantly. The fluid that has flowed into the leaked fluid pressure drop chamber 31 is discharged from the drain hole 33.

On the other hand, the compressed air supplied from the compressed air supply hole 49 is filled in the annular groove 43 and the minute gap 41 on the inner peripheral surface of the flange 35, and the compressed air is supplied to the outside of the joint body 15 and the leaked fluid pressure drop chamber 31 side. It is squirted to both sides. Since the pressure of the fluid in the leaked fluid pressure drop chamber 31 is sufficiently reduced, the air pressure in the annular groove 43 and the minute gap 41 must be maintained at a pressure sufficiently higher than the fluid pressure in the leaked fluid pressure drop chamber 31. Therefore, the fluid in the leakage fluid pressure drop chamber 31 does not leak out of the joint body 15.

In the embodiment described above, a set of pump chambers that generate a dynamic pressure effect is provided in the axial direction to reduce leakage of fluid. However, when the pressure or the flow rate of the fluid is large, by installing a plurality of pump chambers in series, leakage of the fluid to the outside can be eliminated.

However, when the pressure or the flow rate of the fluid is even larger, it is possible to completely eliminate leakage of the fluid to the outside by installing a plurality of pump chambers in the radial direction in addition to the pump chambers in the axial direction. I can do it.

FIG. 3 is a sectional view showing one example. FIG.
Members that are substantially the same as those described above are given the same reference numerals, and descriptions thereof are omitted.

Here, a joint end plate 61 is fitted and fixed to the right end of the joint body 15 via the bolts 63 with the joint body 15. A fluid supply hole 19 is formed at the center of the right end surface of the joint end plate 61, and a joint end plate fluid passage 65 communicating with the fluid supply hole 19 opens at the bottom of the concave portion of the joint end plate 61. The shaft end of the joint shaft 9 is inserted into the concave portion of the joint end plate 61 so as to face the end of the joint end plate fluid passage 65, and the rotation side fluid passage 13 and the joint end plate fluid passage 65 communicate with each other. Thus, fluid can be supplied to the joint shaft 9. At the right end of the joint shaft 9 is a large-diameter flange 6
7 are provided on both of the flat plate portions, as shown in FIG. 4 (A in FIG. 3).
As shown in FIG. 2A, a plurality of spiral dynamic pressure generating grooves 69 are arranged.

A first pump chamber 71 and a second pump chamber 73 are formed by the flat plate portion of the large-diameter flange portion 67, the bottom surface of the concave portion of the joint end plate 61, and the right end surface of the joint body 15, respectively. Further, a plurality of spiral dynamic pressure generating grooves 25 are installed around the small diameter portion of the joint shaft 9 by being connected to the large diameter flange portion 67 of the joint shaft 9, and the joint main body 15 and the small diameter portion of the joint shaft 9 are provided. These form the third pump chamber 75.

The joint end plate 61 and the joint body 15 are sealed by an O-ring 77. A joint end plate compressed air supply passage 79 communicating with the joint body compressed air supply passage 47 is formed in the joint end plate 61, and a compression end communicating with the joint end plate compressed air supply passage 79 is provided at the right end of the joint end plate 61. An air supply hole 49 is open. An O-ring 81 is inserted into the close contact portion between the joint body 15 and the joint end plate 61 to prevent leakage of compressed air.

In the above configuration, a part of the fluid supplied from the fluid supply passage 19 of the joint end plate 61 flows into the first pump chamber 71. In the fluid, a dynamic pressure effect is generated by a pump action of a plurality of spiral dynamic pressure generating grooves 69 provided on the outer peripheral surface of the joint shaft 9 rotating at a high speed, and most of the fluid is returned to the fluid resistance path 23. A small part of the fluid leaks from the pump chamber 71 and flows into the second pump chamber 73. Most of the fluid flowing into the second pump chamber 73 is pushed back by the pumping action of the spiral dynamic pressure generating groove 69 and the centrifugal force generated by the rotation of the joint shaft 9, and the remainder flows into the third pump chamber 75. I do. Most of the fluid is returned to the second pump chamber 73 by the pump action of the plurality of spiral dynamic pressure generating grooves 25 provided on the outer peripheral surface of the joint shaft 9 that rotates at a high speed. The part is the third pump room 7
5, and squirts into the leaked fluid pressure drop chamber 31.

The pressure of the leaked fluid drops when passing through the fluid resistance path 23 and the first pump chamber 71, the second pump chamber 73, and the third pump chamber 75, and the cross-sectional area of the leaked fluid pressure drop chamber 31 is determined by the fluid resistance path. 23 and the first pump chamber 71, the second pump chamber 73, and the third pump chamber 75 are sufficiently large compared to the minute gaps, so that a pressure drop occurs, and the pressure of the fluid filling the leaked fluid pressure drop chamber 33 is the joint end plate. Fluid passage 65,
The pressure is greatly reduced as compared with the fluid pressure in the rotation side fluid passage 13. The fluid that has flowed into the leaked fluid pressure drop chamber 31 is discharged from the drain hole 33.

When the pumping action of the first pumping chamber 71 is large, one or both of the second pumping chamber 73 and the third pumping chamber 75 may be omitted.

[0035]

As is apparent from the above description, the fluid supply joint of the present invention can prevent leakage of fluid supplied from the outside by the pumping action of the pump chamber and can reduce the rotation speed of the rotating body. There is an advantage that there is no limitation, and supply at high pressure is possible regardless of the type of supply fluid.

Further, since the rotating body and the joint body are not in contact with each other, idle operation is possible, and intermittent fluid supply is possible. Furthermore, since bearings and the like are not used in the joint, there is no fear of vibration, heat generation, and the like.

Further, since the fluid in the joint is prevented from leaking to the outside by air pressure filling the minute gap communicating with the leaked fluid pressure drop chamber, the high-pressure fluid is applied to the rotating body in a non-contact state with the rotating body. Can be supplied.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a fluid supply coupling according to the present invention.

FIG. 2 is an external view of a joint shaft according to the first embodiment.

FIG. 3 is a sectional view showing a second embodiment of the fluid supply joint according to the present invention.

FIG. 4 is a sectional view taken along line AA of the joint shaft according to the second embodiment.

FIG. 5 is a sectional view of a conventional fluid supply coupling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotation shaft 9 Joint shaft 9a Outer end face 13 Fluid passage 15 Joint main body 16 Concave part 21a Spout port 23 Fluid resistance path 25 Dynamic pressure generation groove 27 Pump chamber 31 Leakage fluid pressure drop chamber 33 Drain hole 41 Micro gap 45 Compressed air supply path 51 Flange 71 First pump chamber 73 Second pump chamber 75 Third pump chamber

Claims (3)

(57) [Claims] 1. A joint shaft having a fluid passage formed coaxially with a rotation shaft and integrally rotated to form a fluid passage extending from an outer end face of the joint shaft to the rotation shaft. A concave portion was formed so as to be kept in non-contact and close proximity to the side surface and the outer end surface, and a fluid outlet was formed on the bottom surface of the concave portion facing the fluid passage opening on the outer end surface of the joint shaft. A joint body, a fluid resistance path defined between an outer end surface of the joint shaft and a bottom surface of a concave portion of the joint body, a dynamic pressure generating groove formed in the joint shaft, and a concave portion of the joint body. And a pump chamber formed to return the fluid to the fluid resistance path according to rotation of the joint shaft. 2. The joint so as to communicate with the pump chamber.
A leaked fluid pressure drop chamber formed on the side surface of the concave portion of the main body; and a leaked pressure drop chamber opened to the leaked fluid pressure drop chamber.
A drain hole for discharging the fluid to the outside of the joint body.
Fluid supply joint according to claim 1, characterized in that it comprises. 3. A small gap is provided between said joint shaft and said joint shaft.
And a flange provided on the joint body, and the leakage flow is provided from the minute gap.
Compressed air supply for supplying compressed air to body pressure drop chamber
3. The fluid supply coupling according to claim 2 , further comprising a passage .