JP2906008B2 - Rotary joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary joint used for transferring a fluid between a fixed pipe and a rotary pipe.

[0002]

2. Description of the Related Art There is a spindle-through coolant device that circulates a working fluid or pressurized air inside a main spindle device of a machine tool and supplies the working fluid or pressurized air to a tool mounted on a tip of the main spindle. In a known rotary joint that transfers a fluid from a fixed pipeline to a rotary pipeline used in the spindle through coolant device or the like, a rotating shaft and a moving shaft have end faces,
The material of the pair of seal members attached is made of wear-resistant cemented carbide, ceramics, or the like, and its sliding surface is extremely smoothed by lapping or the like.

That is, the moving shaft provided on the fixed conduit side and movable in the axial direction is urged in the axial direction by a compression spring, and the opposed sliding surfaces of the pair of seal members are always
In the contact state, when the pressurized fluid is passed through the fluid passages of the moving shaft and the rotating shaft while driving the rotating shaft, the opposing sliding surfaces of the pair of seal members function as a rotary seal therebetween. The fluid passing through the passage of the moving shaft and the rotating shaft is:
Although the sliding surfaces of the pair of seal members are partially lubricated, the rotary shaft may be driven without passing the fluid through the passage. Wear and heat generation of the sliding surface cannot be avoided, and the service life of the seal member is shortened. In particular, as the rotational speed of the rotating shaft increases, it cannot be left unattended.

In order to solve the above-mentioned inconvenience, a diaphragm is mounted on the fluid passage inlet side of the moving shaft and locked on the housing side, so that the sliding surfaces of the pair of seal members are separated from each other at a fixed position. A rotary joint (see JP-A-3-61786) has been developed. According to this type of rotary joint, the sliding surfaces of the pair of sealing members are always separated, so that even if the rotating shaft side is driven without passing the fluid between the moving shaft and the rotating shaft, the pair of sealing members is Since the sliding surfaces of the members do not contact and slide with each other, there is no possibility that the seal member will be worn.

When a pressurized fluid is passed through the fluid passage of the joint, the fluid pressure acts on the diaphragm to displace the moving shaft in the direction of the rotation axis, thereby pressing and contacting the sliding surfaces of the seal member in a gas-tight manner. Therefore, the airtightness of the rotary joint is maintained. That is, since the sliding surface of the seal member of the rotary joint is in close contact only when a fluid is passed through the joint, it is possible to effectively perform the required function of the rotary joint and, of course, greatly extend the service life of the seal member. Can be.

[0006] As another conventional technique, the moving shaft is air-tightly and plunger-mounted on a housing inner cylinder.
A rotary joint (actually-open flat type 2) which is slidably fitted and axially urges the sliding surfaces of the pair of seal members so as to isolate the sliding surfaces from each other, and is provided with a check valve in the fluid passage of the moving shaft.
19987).

A rotary joint of this type always has
Since the sliding surfaces of the pair of seal members are separated from each other, the sliding surfaces of the pair of seal members do not wear when the rotating shaft is driven without passing the fluid through the passage of the joint. When supplying the pressurized fluid to the fluid passage, the plunger-type moving shaft is first displaced in the direction of the rotating shaft against the urging force by the same fluid pressure, and the sliding surfaces of the pair of seal members are brought into airtight pressure contact with each other, Ensuring the sealing action of the member. Thereafter, the check valve provided in the fluid passage of the moving shaft is opened by the pressure fluid, so that the pressure fluid passes through the passage after the airtightness of the sliding contact surfaces of the pair of seal members is completed. .

[0008]

SUMMARY OF THE INVENTION Incidentally, Japanese Patent Application Laid-Open No.
When a liquid is allowed to flow through a fluid passage of a rotary joint disclosed in Japanese Patent No. 61786, the liquid is introduced in a non-contact state with a pair of seal members. Part of the liquid exerts pressure on the diaphragm, displacing the moving shaft against the elastic biasing force of the diaphragm, and bringing the pair of seal members into contact, but also during this time, part of the introduced liquid is the fluid of the moving shaft It begins to flow through the passage and leaks between a pair of seal members that have not yet contacted. However, the pair of seal members immediately come into contact with each other, and thereafter, no leakage occurs. When the supply of the liquid is stopped during the flow of the liquid, when the pressure acting on the diaphragm is reduced, the pair of seal members is brought into a non-contact state, and the pair of seal members is provided for a short time until the supply of the liquid is completely stopped. Liquid leaks from between. As described above, there is a problem that the liquid leaks from between the pair of seal members in the transient state at the time of starting and stopping the supply of the liquid.

Next, when a liquid is allowed to flow through the fluid passage of the rotary joint disclosed in Japanese Utility Model Laid-Open No. 2-19987, a check valve provided in the fluid passage is opened after a pair of seal members come into contact with each other, and the liquid is allowed to flow. In the case of circulating and stopping the supply of the liquid, the pair of seal members are brought into a non-contact state after the check valve is closed, so that there is almost no leakage of liquid from between the pair of seal members. However, the spring pressure of the check valve must be set in accordance with the pressure of the supplied liquid, and the check valve is provided in the fluid passage of the rotary joint, so that the structure of the rotary joint is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to prevent the liquid from leaking between the pair of seal members even when the liquid is supplied to the rotary joint and when the liquid is stopped, and to reduce the wear of the pair of seal members. It is intended to provide a rotary joint having a small number and a simple structure.

[0011]

According to the present invention, a gas is introduced prior to the flow of a liquid to be supplied to a rotary joint, a pair of seal members are brought into contact with each other, and the liquid to be supplied is circulated. The gas is introduced at the same time as or shortly before the liquid supply is stopped, and the supply of the liquid and the gas is controlled so that the pair of seal members are kept in contact for a predetermined time after the liquid supply is stopped. It is.

That is, the present invention has been made to solve the above problems.
It is configured as follows.

A housing, and a housing provided in the housing.
A rotating shaft having a fluid passage in an axial center thereof;
Inside the shaft and opposed to the rotation axis, and move in the axial direction
A movable shaft having a fluid passage in the axial center portion, the movable shaft being fitted to
A pair of rotating shafts and a moving shaft
A tension member is provided between the housing and the moving shaft.
So that the pair of seal members are in a non-contact state.
A diaphragm for biasing the moving shaft, and the pair of
Supply gas or liquid so that tool members are in contact
A space for applying pressure to the diaphragm,
Prior to the supply of liquid to the fluid passage,
Before supplying the gas and bringing the pair of sealing members into contact with each other,
Supply the liquid to the fluid passage, and
Connects a gas supply source to the fluid passage before the supply is stopped
Gas for a predetermined time after the supply of liquid is stopped,
A control means for controlling the sealing member to maintain the contact state
A rotary joint comprising a step.

[0014]

According to the present invention, liquid supply is started or stopped with the pair of seal members kept in contact with the gas pressure, so that no liquid leaks from between the pair of seal members. .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. However, it is apparent from the above description that the present invention is not limited to only the embodiments described below. . In addition, some of the components of the present embodiment described below include those that can be arbitrarily modified by those skilled in the art within the range of technical levels known in the art at the time of filing the present application. In view of the above, the gist of the present invention should not be limited and understood based only on the configuration of the present embodiment without showing any particular reason.

FIG. 1 shows a first embodiment of the rotary joint according to the present invention.
FIG. 2 is a sectional view showing the configuration of the embodiment, and FIG. 2 is a sectional view taken along line II-II of FIG. A rotary joint 1 is attached to a rear end of a spindle device 3 of a machine tool. The spindle device 3 has a configuration in which a spindle 9 is rotatably supported on a spindle head 5 by a bearing 7.

Meanwhile, the first housing 11 of the rotary joint 1 is fixed to the spindle head 5 the end face on the main shaft 9 coaxially. The rotary shaft 13 of the rotary joint 1 is fixed to the end face of the main shaft 9 by screw connection coaxially with the main shaft 9, and is housed in a space formed in the first housing 11.

A seal member 15 is fixed to an end surface of the rotating shaft 13 opposite to the main shaft 9. A seal member 17 facing the seal member 15 is fixed to one end surface of the moving shaft 19,
Is fitted in the cylindrical hole 21 of the first housing 11 so as to be movable in the axial direction.

A diaphragm 31 is fixed with its outer periphery sandwiched between the first housing 11 and the second housing 12 and its inner periphery fixed to the moving shaft 19 to isolate the first housing 11 from the second housing 12. It is stretched to be. The movable shaft 19 is constantly urged in the opposite direction to the main shaft 9 by the elastic force of the diaphragm 31, so that the pair of seal members 15, 17 are brought into a non-contact state. The seal member 17 side of the moving shaft 19 has a flange shape, and a notch formed in the flange shape portion.
The rotation is prevented by the engagement between the pin 22 and the pin 23.

Further, in the space inside the first housing 11,
An annular projection 27 of the housing is formed and a collar 25 is attached by a snap ring with a gap. A carbon ring 29 is fitted on the rotating shaft 13 and is mounted between the collar 25 and the annular projection 27 so as to be fitted in the first housing 11.
And the rotating shaft 13 constitute a sealing means.

In the first housing 11, a space 59 for accommodating the pair of seal members 15, 17 is formed.
The communication passage 33 communicates with a space 35 surrounded by the first housing 11, the diaphragm 31, and the outer periphery of the moving shaft 19. The space 59, the communication passage 33, and the space 35 form a second space, and ports 41 and 43 are opened in the second space.

On the other hand, inside the second housing 12, a first space 37 for receiving a fluid for applying pressure to the diaphragm 31 is provided.
Is formed, and the port 39 is open. The component “space” described in the claims is the first space 37. The port 43 is connected to a drain tank 47 via an electromagnetic valve 45.

The machining fluid from the machining fluid supply source is supplied to the solenoid valve 48.
And introduced to port 39 via check valve 49,
Further, the air from the pressurized air supply source is introduced into the port 39 via the solenoid on-off valve 51 and the check valve 53, and the air from the pressurized air supply source is further supplied via the electromagnetic on-off valve 55 to the port 39.
Piped to be introduced to 41. Solenoid on-off valve 45, 4
The opening / closing timing of 8, 51, 55 is controlled by the control means 60. A coaxial fluid passage 57 is formed in the moving shaft 19, the seal members 15 and 17, the rotating shaft 13, and the main shaft 9, and a working fluid or pressurized air is attached to a tool (not shown) having a tip mounted on the main shaft 9. It is supposed to be sent.

FIG. 3 shows a second example of the rotary joint of the present invention.
In the sectional view showing the configuration of the embodiment, the same components as those of the first embodiment are denoted by the same reference numerals. A configuration other than the configuration in which the rotary shaft 13 is supported via the bearing 61 on the first housing 11 of the rotary joint 1, for example, the mounting of the moving shaft 19, the arrangement of the pair of seal members 15 and 17, the collar 25 and the annular protrusion 27 Moving shaft 19 with carbon ring 29 and diaphragm 31 sandwiched between
The configuration of the urging, working fluid, air, drain piping, fluid passage 57, and the like are the same as those in the first embodiment, and thus description thereof is omitted.

The second embodiment shows a state in which the diaphragm 31 is displaced together with the moving shaft 19 by the fluid pressure introduced into the first space 37, and the pair of seal members 15, 17 are in contact. The configuration different from the first embodiment is that the rotary joint 1 itself has a bearing 61 and is a unit type in which one end of the rotary shaft 13 is connected to the rear end of the main shaft 9. First
The rotary joint 1 of the embodiment has no bearing in itself, and is of a type that functions only when mounted on an external rotary shaft device such as a main shaft device.

Next, the operation of the first embodiment and the second embodiment will be described. When the main shaft 9 is rotated without flowing the machining fluid and the air, the elastic biasing force of the diaphragm 31
The pair of seal members 15, 17 are in a non-contact state. Then, even if the main shaft 9 rotates, the seal members 15 and 17 do not slide and thus do not wear. FIG. 1 shows such a state.

Next, when the working fluid flows through the fluid passage 57, the solenoid valves 45 and 48 are opened, the solenoid valves 51 and 55 are closed, and the machining fluid is introduced from the port 39. Processing fluid is
Pressure is applied to the diaphragm 31 in the first space 37,
The diaphragm 31 is moved together with the moving shaft 19 against the elastic force to bring the pair of seal members 15 and 17 into contact with each other, and the working fluid is supplied to the front end of the main shaft 9 through the fluid passage 57.

At this time, there is almost no leakage of the working fluid from between the pair of seal members 15, 17, and a small amount of the working fluid leaks due to the opening of the solenoid on-off valve 45.
From the drain tank 47. A pair of sealing members 1
The wear of the sliding surface of the seal member is minimized by the lubricating action of the exuded working fluid between the sliding contact surfaces 5 and 17. FIG. 3 shows a state in which the working fluid is supplied. When the supply of the working fluid is stopped, the pressure acting on the diaphragm 31 is eliminated, so that the moving shaft 19 is returned by the elastic urging force of the diaphragm 31, and the pair of seal members 15, 17 are brought into a non-contact state.

Next, when flowing the pressurized air through the fluid passage 57, the solenoid valves 45 and 48 are closed, and the solenoid valves 51 and 55 are opened to introduce the pressurized air into the ports 39 and 41. Then, the pressure in the second space formed by the space 59, the communication passage 33, and the space 35 becomes equal to the pressure in the first space 37.
The pressure that presses 31 in either direction does not act and the moving shaft 19
Does not move. That is, the pair of seal members 15, 17 remain in a non-contact state. In this state, the pressurized air is supplied through the fluid passage 57 toward the tip of the main shaft 9. The solenoid valve 51
May be closed, only the electromagnetic on-off valve 55 is opened, and pressurized air is introduced only from the port 41 to flow through the gap between the pair of seal members 15, 17 to the fluid passage 57.

When the air is circulated in this way, the pair of seal members 15 and 17 are kept in a non-contact state, so that the seal members 15 and 17 do not wear or friction. Solenoid on-off valve 51
Open, close the solenoid on-off valve 55 and supply pressurized air to port 39.
When the pressure is introduced only from the above, the pressure acts on the diaphragm 31 to move the moving shaft 19, so that the pair of seal members 15, 17 come into contact with each other, and wear and friction of the seal members 15, 17 occur, which is not preferable. The working fluid and air are prevented from leaking from the gap between the rotating shaft 13 and the first housing 11 by the rotating shaft 13, the collar 25, and the carbon ring 29 slidably contacting the annular projecting portion 27.

Next, the operation when the working fluid is circulated through the rotary joint 1 will be described with reference to the timing chart of opening and closing the solenoid on-off valve by the control means of the present invention in FIG. As described above, when the machining liquid is introduced into the port 39 by opening the electromagnetic on-off valve 48, the diaphragm 31 is pressed by the pressure, and the pair of sealing members 15 and 17 pass through the fluid passage before they come into contact with each other. The machining fluid that reaches 17 is a seal member
Leak from between 15 and 17. Further, when the electromagnetic on-off valve 48 is closed and the introduction of the working fluid into the boat 39 is stopped, the pressure in the first space 37 is reduced, and the pressing force on the diaphragm 31 disappears,
The pair of seal members 15, 17 are in a non-contact state. At that time, a slight flow of the working fluid in the fluid passage remains and leaks from between the seal members 15 and 17. Sealing members 15 and 17 for the working fluid in the transient state of the supply start and stop of the working fluid.
Before and after starting supply of machining fluid,
Before and after the supply of the working fluid is stopped, pressurized air is supplied to the port 39 for a certain time, and the working fluid is supplied to the pair of seal members.
The seal members 15 and 17 may be brought into contact with each other by air pressure at the time of starting and ending the flow between 15 and 17.

More specifically, first, the solenoid on-off valve 45
Is opened, and the solenoid on-off valve 55 is closed. A predetermined time before opening the electromagnetic on-off valve 48, the electromagnetic on-off valve 51 is opened, pressurized air is introduced into the port 39, the pair of seal members 15, 17 are brought into contact, and then the electromagnetic on-off valve 48 is opened. Then, a working fluid higher in pressure than air is introduced into the port 39. At this time, since the pressure of the working fluid is higher than the pressure of the air, the check valve 53 is closed, and the working fluid flows into the fluid passage while pushing the air in the pipeline, that is, pushing the diaphragm 31 to form a pair of fluids. It passes through the place where the sealing members 15 and 17 are in contact.

Thereafter, the electromagnetic valve 51 is closed, and the supply of air is stopped. Here, even if the electromagnetic on-off valve 51 is left open, air is not supplied to the port 39, so that it may be left open.

This time, when the electromagnetic on-off valve 48 is closed, the electromagnetic on-off valve 51 is opened at the same time as or shortly before, and a pair of seal members is opened.
When the contacts 15 and 17 maintain the contact state, the supply of the working fluid is stopped, the inside of the fluid passage is cleaned with air for a predetermined time, and then the electromagnetic on-off valve 51 is closed. Thus, the solenoid on-off valve 48,
By controlling 51 by the control means 60, the sealing member
Leakage of machining fluid from between 15 and 17 can be eliminated.

It should be noted that the working fluid electromagnetic on-off valve 48, check valve
The piping having 49 and the piping having the electromagnetic open / close valve 51 and the check valve 53 for pressurized air may be connected to the port 39 in parallel, or the processing fluid may be directly provided without the electromagnetic open / close valves 48 and 51. The supply source and pressurized air supply source may be turned off at 0N. The shorter the time during which only air flows through the fluid passage, the better in terms of wear of the seal members 15 and 17. Stop the supply of machining fluid after stopping the rotation,
When the pair of seal members 15 and 17 are in contact with each other and allow only air to flow, care must be taken not to rotate the main shaft.

[0036]

As described above, the present invention has the following advantages. (1) When the supply of liquid to the rotary joint is started or stopped, leakage of liquid from between the pair of seal members does not occur. (2) Since there is almost no time during which only the gas flows with the pair of seal members in contact with each other, wear and friction of the seal members do not matter. (3) Since the supply timing of the liquid and the gas to the rotary joint may be controlled without changing the configuration of the rotary joint, the structure of the rotary joint is not complicated. For example, there are effects that cannot be expected from the conventional device.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of a rotary joint according to the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG.

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

FIG. 4 is a supply timing chart of processing fluid and air by the control means of the rotary joint of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary joint 3 Spindle device 5 Spindle head 7 Bearing 9 Spindle 11 1st housing 12 2nd housing 13 Rotating shaft 15, 17 Seal member 19 Moving shaft 23 Pin 25 Collar 27 Annular projection 29 Carbon ring 31 Diaphragm 33 Communication passage 35 Space 37 First space 39, 41, 43 Port 57 Fluid passage 60 Control means 61 Bearing.

Claims (1)

(57) [Claims] A housing, a rotation shaft provided in the housing, and having a fluid passage in an axis portion; a housing disposed in the housing so as to face the rotation shaft, and fitted to be movable in an axial direction; A moving shaft having a fluid passage in an axis portion, a pair of seal members provided on a surface facing the rotating shaft and the moving shaft, and a pair of the sealing members stretched between the housing and the moving shaft; A diaphragm that urges the moving shaft so that the seal member is in a non-contact state; and a space that supplies gas or liquid so that the pair of seal members is in a contact state to apply pressure to the diaphragm; Prior to the supply of the liquid to the fluid passage, a gas is supplied to the space for a predetermined time to bring the pair of seal members into contact.
The liquid was supplied before Symbol fluid passage Te, outage simultaneously liquid
Or, before the supply is stopped, a gas supply source is
After the connection and the supply of liquid is stopped,
Control means for controlling the pair of seal members so as to maintain the connected state, the rotary joint comprising: