JPH1163335A - Rotary joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary joint that can be compactly designed even in case of the inner pipe diameter of a fluid passage being large while minimizing leakage of a fluid. SOLUTION: A rotary joint 1 is provided with a rear housing 4, an intermediate housing 3, and a front housing 2 provided with an air inflow port 5. A floating seat 10 disposed in an axially movable state in these housings and provided with a sealing member 11 at the end face, and a rotary shaft body 20 provided with a fixed member 21 and a support member 22 axially movable but not rotatable in relation to the fixed member 21 are coaxially arranged so that a sealing member 23 provided at the end face of the rotary shaft body 20 and a sealing member 11 provided at the end face of the floating seat 10 are opposed to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary joint for supplying a fluid to a main shaft of a machine tool, and more particularly to a rotary joint suitable for high-speed rotation.

[0002]

2. Description of the Related Art A rotary joint fluidly connects a rotating part and a fixed part in a machine tool or the like in order to supply a fluid to the rotating part from a fixed part. Some machine tools have a structure that sends lubricating fluid, cooling fluid, air, etc. to the tip of the rotating part to reduce friction and wear generated at the contact part when the rotating part such as the main shaft rotates. In such cases, rotary joints are commonly used.

A conventional rotary joint for machine tools is disclosed in Japanese Patent Application Laid-Open No. 9-100976. The rotary joint includes a rotating member and a piston member having a check valve function constantly urged rearward in a housing. A pressing member constantly urged forward with respect to the piston member is provided in the piston member, and a pair of seal members are fixed to the opposing surfaces of the pressing member and the rotating member. Further, the piston member, the pressing member, and the rotating member are provided with a fluid passage at the axis. When liquid is supplied from the fluid supply port, the pressure of the supplied liquid causes the piston member to move forward, bringing the pair of seal members into contact with each other. Supplied to When the supply of the liquid is stopped and the pressurized air is supplied from the pressurized air supply port, the pressurized air is supplied to the fluid passage in the main shaft through the gap between the pair of seal members.

Since this rotary joint has a two-stage structure in which a pressing member is inserted into a piston member, the contact pressure of the pair of seal members applies the pressing member forward regardless of the magnitude of the pressure of the supply liquid. It becomes a constant value equal to the urging force.

[0005]

However, since the conventional rotary joint as described above employs a two-stage structure in which a pressing member is inserted into the piston member, the pressing member or the like is inserted into the piston member. A space or structure for storing a spring or the like for urging the pressing member forward is required. Therefore, the structure of the piston member becomes large and complicated,
A large structure is also required for the housing that stores the piston member. With this two-stage structure, when manufacturing a compact rotary joint, the inner pipe diameter of the fluid supply path is limited, so that there is a problem that the flow rate of the flowing liquid is limited.

According to the present invention, when a main shaft is rotated at a high speed to flow a fluid through a rotary joint, fluctuations in the sliding pressure and the sliding area between the seal members are suppressed flexibly in response to changes in the pressure of the fluid. Accordingly, an object of the present invention is to provide a rotary joint that can be compactly designed even when the inner pipe diameter of the fluid flow passage is increased while minimizing fluid leakage.

[0007]

In order to achieve the above object, a rotary joint according to the present invention has a hollow passage inside, a rotary shaft body attached to a main shaft in rotation with the main shaft, and a hollow passage inside. A floating seat, which is disposed in a fixed housing in a non-rotating state and is movable in the axial direction, and opposes seal members attached to respective ends thereof with a gap provided therebetween, and Disposed, the floating sheet is elastically urged in a direction opposite to the opposing direction of the seal members to close the inlet-side flow path, and axially moves against the elastic urging force by fluid pressure,
The rotary joint, in which the inlet-side flow path is opened and the hollow path of the rotary shaft and the hollow path of the floating sheet communicate with each other due to contact between the seal members, and a fluid flows from the floating sheet side to the rotary shaft side, A first stopper that restricts the movement of the floating sheet in the opposing direction, and a fixed member that rotates in conjunction with the main shaft, and is movable in the axial direction with respect to the fixed member and is elastic in the opposing direction. The support member is configured to be urged and stopped by a second stopper provided on the fixing member, and a seal member fixed to an end of the support member. In addition,
The above-mentioned `` facing direction '' means a direction in which the seal members face each other, and when viewed from the floating sheet side, means a direction from the floating sheet to the rotating shaft body, and when viewed from the rotating shaft body side. , Means the opposite direction. The “opposing direction” described below is used in this sense.

[0008] As described above, since the conventional two-stage structure is not adopted as the structure of the floating seat by providing the elastically biased support member on the fixed member on the rotating shaft side, a compact rotary joint can be designed. Thus, the inner pipe diameter of the hollow passage provided in the floating sheet, the fixing member, and the support member can be designed to be large.

[0009] In addition to the above configuration, the floating sheet closes the inflow-side channel by an elastic urging force,
Further, the distance between the two seal members in a state where the support member is stopped by the second stopper of the fixed member is configured to be smaller than the moving distance of the floating sheet required to open and close the flow path. In addition, it is possible to prevent liquid leakage that is likely to occur when opening and closing the inlet-side flow path.

When the fluid pressure exceeds a certain value, the floating sheet of the present invention moves in the opposite direction against the elastic urging force, and the sealing member at the end of the floating sheet and the sealing member at the end of the rotating shaft body. The member comes into contact with the hollow passage of the floating sheet and the hollow passage of the rotary shaft body to communicate with each other to form a fluid flow passage for supplying fluid to the tip of the main shaft. Thereafter, when the floating sheet further moves, the flow path is opened and the fluid is guided to the fluid flow passage.
In addition, a first stopper is provided in the housing to limit the movement of the floating sheet in the facing direction, and
The present invention provides a rotating shaft body including a support member movable in the axial direction with respect to the fixed member and elastically biased in the opposite direction, and a seal member attached to an end of the support member.
Fluid pressure can flexibly correspond to a wide pressure range from low pressure to high pressure.

That is, when the fluid pressure is higher than the minimum pressure of the fluid required to open the flow path (hereinafter referred to as flow path opening / closing pressure) and relatively weak, the floating sheet mainly
The floating sheet stops at an equilibrium position between the elastic urging force of the floating member and the support member and the fluid pressure, but when the fluid pressure is relatively higher than the flow path opening / closing pressure, the floating sheet is moved to the first stopper before reaching the equilibrium position. Therefore, the contact pressure between the seal members does not increase more than necessary.

Further, since the distance between the seal members is configured to be smaller than the moving distance of the floating sheet required to open and close the flow path, the seal members surely come into contact with each other before the flow path is opened. Therefore, leakage of the fluid can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, typical embodiments according to the present invention will be described with reference to the drawings.

FIGS. 1 and 2 are cross-sectional views of the rotary joint according to the present invention passing through the central axis. FIG. 1 shows a non-contact state between the seal members of the rotary joint 1, and FIG. 2 shows a contact state between the seal members when a relatively high-pressure fluid such as a working fluid is flowing. FIG. In addition, a main shaft 40 is attached to the rotary shaft body 20 of the rotary joint in both figures.

The housing includes a rear housing 4 provided with a fluid inlet 7 and an air inlet 6, a middle housing 3 provided with a stop 8, and a front housing 2 provided with an air inlet 5. And is fixed to a fixed portion other than the main shaft 40. The front housing 2 and the middle housing 3, and the middle housing 3 and the rear housing 4 are connected by screws 9, 9,. In this housing, a floating sheet 10 provided with a seal member 11 on an end face is disposed so as to be movable in the axial direction. In addition, the rotating shaft body 20 provided with the sealing member 23 on the end face is mounted on the end of the main shaft 20 so as to rotate together with the main shaft 40, and the sealing member 23 provided on the rotating shaft body end face and the floating sheet 10 are provided. Are arranged coaxially with the floating sheet 10 so that the seal member 11 provided on the end face of the floating sheet 10 faces the same. Seal member 1
As the materials 1 and 23, one is made of a material having a high hardness such as SiC or WC, and the other is made of a special high-hardness member or a material having a relatively low hardness such as carbon depending on the application.

The floating sheet 10 has a hollow path 16 along the axis. The hollow passage 16 is opened through the seal member 11 on the end surface of the floating sheet. On the side opposite to the opening in the axial direction, the end surface is closed, and a through hole 17 penetrating the floating sheet 10 in the radial direction is formed. Communicating. The fluid flows from the through hole 17 and flows through the hollow passage 16 to the opening of the seal member 11. An annular stopper 12 is joined to the entire outer periphery of the floating seat, and the outer periphery of the stopper is in contact with the inner surface of the rear housing 4. Sealing members 13, 13 such as O-rings are provided at the joint between the floating sheet 10 and the first stopper 12 and at the contact between the first stopper 12 and the rear housing 4. Is designed not to leak. Further, a spring 14 that elastically urges the first stopper 12 in a direction opposite to a direction in which the seal members face each other is provided between the first stopper 12 and the middle housing 3. Further, the guide pins 15, 15 are fixed to the middle housing 3, and engage with the engagement holes 19 provided in the flange portion 18 of the floating seat 10, thereby facilitating the axial movement of the floating seat 10. , And serves to stop the axis rotation movement of the floating sheet 10.

The rotating shaft 20 includes a fixing member 21 attached to the end of the main shaft 40, and a supporting member 22 that cannot rotate and can move in the axial direction with respect to the fixing member 21.
And a seal member 2 provided on an end face of the support member 22.
3 and a spring 25 that elastically urges the support member 22 in a direction opposite to the fixing member 21. The rotation shaft side spring 25 is provided between the fixed member 21 and the support member 22. Further, the hollow passage 28 through which the fluid flows,
29, along the axis, the fixing member 21, the support member 22,
And a seal member 23 provided on the end surface of the support member. Also, the guide pins 24, 24
The support member 22 is fixed to the fixing member 21 in parallel with the axial direction and engages with a notch hole 32 provided in the flange portion 31 of the support member 22 to facilitate movement of the support member 22 in the axial direction. And stops the rotation of the shaft with respect to the fixing member 21. Further, a stop ring serving as the second stopper 30 is fixed to the inner periphery of the fixing member 21 to limit the movement of the support member 22 in the facing direction. The main shaft 4
A sealing member 26, such as an O-ring, is provided at the joint between the fixing member 21 and the fixing member 21 and the contact between the fixing member 21 and the supporting member 22.
27 is provided to prevent liquid and the like from leaking out of the hollow path from the joint or contact portion. In actual use, the fixed member 21 is engaged with the main shaft 40.
At this time, the fixing member 21 is interlocked with the rotational movement of the main shaft 40.
And the support member 22 rotates. As shown in FIG. 1, the floating sheet 10 closes the inflow channel by the elastic force of the spring 25, and the second stopper 30 is pressed while the support member 22 is pressed by the spring 25 in the facing direction.
The distance between the two seal members in the state of being stopped is configured to be smaller than the moving distance of the floating sheet required to open and close the inlet-side flow path. This is to prevent the inlet-side flow path from opening before the two seal members contact each other when a fluid having a pressure higher than the flow path opening / closing pressure flows.

In the rotary joint 1 having the above-described structure, when a relatively low-pressure fluid is fed into the fluid inlet 7, as shown in FIG.
Numeral 0 closes the flow path on the inlet side by the elastic force of the spring 14, and the support member 22 of the rotating shaft 20 is pressed against the second stopper 30 while being pushed in the opposite direction by the elastic force of the spring 25. The seal members 11 and 23 are not in contact with each other. At this time, the floating seat 10 is pressed against the elastic force of the spring 14.
To open the channel. In order to feed compressed air or the like to the tip of the spindle, the air inlet 5 or 6 is used. The air flowing from the air inlet 5 or 6 is sent to the tip of the main shaft through the hollow passage 16 of the floating sheet 10 and the hollow passages 28 and 29 of the rotary shaft 20. At this time, since the seal members do not come into contact with each other or slide, wear and friction of the seal members do not occur. When supplying pressurized air, it is necessary to prevent the seal members 11 and 23 from coming into contact with each other.
It is desirable to use the air inlet 5 provided toward the gap 3.

Next, a fluid having a pressure slightly higher than the flow path opening / closing pressure,
For example, when a working fluid or the like flows into the fluid inlet 7,
Floating sheet 1
0 moves, and the floating sheet side seal member 11 comes into contact with the rotary shaft side seal member 23, so that the hollow path 16 of the floating sheet 10 and the hollow path 28 of the rotary shaft body 20 communicate with each other. Thereafter, the floating sheet 10 further moves in the opposite direction to open the flow path on the inlet side, and the machining fluid and the like flowing from the fluid inlet 7 flow through the communicating hollow passages 16, 28, 29, and the main shaft. Supplied to the tip. The movement of the floating sheet 10 mainly depends on the elastic force and the fluid pressure applied to the floating sheet and the support member 2.
It stops when the elastic force applied to 2 equilibrates. More precisely, in addition to these forces, a force pressing in the opposite direction also acts on the support member 22 due to the pressure balance.

At this time, the support member 22 is
Therefore, the floating sheet 10 can be moved while the seal members 11 and 23 are in contact with each other to open the flow path. Further, when the machining fluid or the like is circulated while the rotating shaft body 20 rotates in conjunction with the main shaft 40,
The spring 25 reduces the sliding pressure between the seal members, the runout of the rotary shaft 20 following the runout of the main shaft 40, and the thermal expansion of the rotary shaft 20 and the seal member caused by frictional heat and the like. Therefore, the friction and wear of the sealing member are reduced without impairing the sealing performance.

Next, when a working fluid or the like considerably higher than the flow path opening / closing pressure flows into the fluid inlet 7, the floating sheet 10 moves due to the pressure of the working fluid or the like, and the state shown in FIG. Becomes That is, the sealing member 1
While the floating sheets 10 and 23 are in contact with each other,
The stopper 12 provided on the middle housing 3 is in a state of abutting against the abutting portion 8 of the middle housing 3. At this time, the contact pressure between the sealing members 11 and 23 provided on the floating sheet 10 and the rotating shaft body 20 is mainly determined by the elastic force of the spring 25 applied to the support member 22. Here, the elastic force of the spring 25 is adjusted by pressure balance in consideration of the force pressing the support member 22 in the direction in which the seal members face each other. Thus, even if a high-pressure fluid flows through the rotary joint, the seal members 11 and 23 do not need to receive the fluid pressure entirely. Therefore, since excessive contact pressure is not applied between the seal members 11 and 23, friction and wear between the seal members 11 and 23 are reduced.

As described above, the rotary joint 1 according to the present invention adjusts the elastic urging force on the floating sheet 10 and the elastic urging force on the support member 22 so that the fluid pressure can be changed from a low pressure to a high pressure. Can respond flexibly to the range.

[0023]

The rotary joint according to the present invention has a first stopper in the housing for restricting the movement of the floating seat in the facing direction, and the rotary shaft body can move in the axial direction with respect to the fixed member. And a support member elastically biased in the opposite direction, and a seal member fixed to an end of the support member.
The fluid pressure can flexibly correspond to a wide pressure range from low pressure to high pressure, and the friction and wear of the seal member can be reduced. Further, according to this configuration, since a conventional two-stage structure is not adopted as the structure of the floating seat, a compact design is possible, and a large inner pipe diameter of the hollow passage through which the fluid flows can be secured, so that a large flow rate can be secured.

Further, the distance between the two seal members in a state where the floating sheet closes the flow path on the inlet side by the elastic urging force and the support member is stopped by the second stopper of the fixed member is the flow path. When it is configured to be smaller than the moving distance of the floating sheet required to open and close, when high-pressure fluid such as machining fluid flows in,
Since the seal members can be brought into contact with each other before the flow path is opened, it is possible to prevent the leakage of the working fluid or the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a rotary joint according to the present invention, showing a non-contact state between seal members.

FIG. 2 is a sectional view showing a contact state between seal members in the rotary joint according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary joint 2 Front housing 3 Middle housing 4 Rear housing 5, 6 Air inlet 7 Fluid inlet 8 Stop part 10 Floating seat 11 Seal member 12 First stopper 13 Sealing member 14 Spring 15 Guide pin 16 Hollow path 17 Through-hole 18 Flange part of floating sheet 19 Engagement hole 20 Rotating shaft 21 Fixed member 22 Support member 23 Seal member 24 Guide pin 25 Spring 26, 27 Seal member 28, 29 Hollow path 30 Second stopper 31 Flange of support member Part 32 Notch hole 40 Main shaft

Claims (2)

[Claims] 1. A rotary shaft body having a hollow passage therein and attached to a main shaft in a rotating state together with the main shaft, and a non-rotating state and axially inside a fixed housing having a hollow passage therein. A floating sheet movably disposed opposes the seal members attached to respective ends thereof with a gap provided therebetween, and is coaxially disposed, and the floating sheet is in a direction opposite to a direction in which the seal members oppose each other. From the state in which the inlet-side flow path is closed by being elastically urged, the shaft moves against the elastic urging force by the fluid pressure, the inlet-side flow path is opened, and the rotating shaft is brought into contact by the seal members. A rotary joint in which the hollow passage of the body and the hollow passage of the floating sheet communicate with each other and a fluid flows from the floating sheet side to the rotary shaft side; A first stopper for restricting movement of the seal member in the opposite direction, wherein the rotating shaft body rotates in conjunction with the main shaft, and the seal member is movable with respect to the fixed member in the axial direction. A rotary joint, comprising: a support member elastically biased in a facing direction and stopped by a second stopper provided on the fixed member; and a seal member fixed to an end of the support member. 2. The space between the two seal members in a state where the floating sheet closes the flow path on the inlet side by an elastic urging force and the support member is stopped by the second stopper of the fixed member is the flow path. The rotary joint according to claim 1, wherein the rotary joint is configured to be smaller than a moving distance of a floating sheet required to open and close the rotary seat.