JPH0762512B2 - Rotary joint for refueling - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving a rotary joint for refueling used in a machining center or the like.

[0002]

2. Description of the Related Art In a conventional rotary joint for refueling of this type, a casing having a flow passage in the axial direction on the stationary side and a casing having a flow passage in the axial direction to rotatably support a shaft in the casing. And a rotary tube shaft on the rotating side, and an insert provided on the inner end surface of the rotary tube shaft by fluid pressure so as to be slidable in the axial direction of the seal hole formed in the flow path of the casing. A floating seat that is rotatably connected by a seal, a check valve that is provided in the casing and that opens the flow path of the casing by fluid pressure, and a floating seat that is mounted between the casing and the floating seat. A seal release spring that urges the surface to slide away from the seal surface of the insert seal, and the check valve has a floating seal. The repulsive force of the seal-releasing spring, which is provided in the communication hole of the valve, has a size such that the floating seat slides due to the fluid pressure lower than the cracking pressure of the check valve, and the sealing surface makes pressure contact with the sealing surface of the insert seal. The set one is known.

[0003]

However, in this conventional rotary joint for refueling, since the check valve is provided in the communication hole of the floating seat, extra parts such as a valve spool and a spring are required, so that the assembly is not possible. There is also a problem that cost is increased because it takes time and labor to manage parts and components. Also, in order to increase the size of the check valve and reduce the pressure loss, the floating seat must be enlarged, and the rotating part cannot be made compact, and the large rotating part is disadvantageous for high-speed rotation. was there.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to:
A rotary joint with a check valve that prevents the seizure of the seal member by separating the sealing surface of the floating sheet from the sealing surface of the insert seal when fluid pressure does not act on the flow path. It is an object of the present invention to provide a rotary joint for refueling that has a small number of points and has a compact check valve structure that is advantageous for high-speed rotation.

[0005]

As a means for achieving the above object, in the rotary joint for refueling of the present invention,
A casing having a flow passage in the axial direction and on the fixed side, a rotary tube shaft having a flow passage in the axial direction and rotatably supported in the casing on the rotation side, and a flow passage in the casing. A floating sheet that is slidably mounted in the formed seal hole in the axial direction thereof and is rotatably seal-connected with an insert seal provided on the inner end surface of the rotary pipe shaft by fluid pressure; A check valve that is provided in the opening of the casing to open the flow path of the casing by a fluid pressure, and a seal that is mounted between the casing and the floating seat and that biases the floating seat in a direction in which its sealing surface separates from the sealing surface of the insert seal. In a rotary joint for refueling provided with a release spring, the valve spool of the check valve has a floating seat. While being formed integrally with Lumpur hole mounting tip, it has a configuration in which the valve seat is formed on the upstream side opening edge of the seal hole.

[0006]

In the rotary joint for oil supply of the present invention, the valve spool of the check valve is integrally formed at the tip of the seal hole mounting portion of the floating seat, so that the valve spool receives hydraulic pressure when the cutting oil is supplied and the seal is released. The floating seat slides to the downstream side against the repulsive force of the spring, and the sealing surface and the insert seal provided on the rotary tube shaft are pressed together to connect both flow paths, and away from the valve seat. The cutting oil can be supplied from the fixed side to the rotating side by opening the opening and allowing the cutting oil to flow. In addition, when the cutting oil is stopped, the hydraulic pressure in the flow path disappears, so the floating seat slides upstream due to the repulsive force of the seal release spring, separating its seal surface from the seal surface of the insert seal and removing the valve spool. It will be in close contact with the valve seat and close the flow path. Therefore, since the rotary tube shaft does not have a contact portion with the fixed side, even if the rotary tube shaft is rotated in this state, it is possible to prevent heat generation and seizure of the seal member.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. In addition, in this embodiment, the case of being used as a rotary joint for refueling of a machining center is taken as an example. First, the configuration of the embodiment will be described. Rotary joint A for lubrication in the machining center of this embodiment
As shown in FIG. 1, the casing 1 and the rotary tube shaft 2 are
The rotary seal member 3 and the check valve 4 are provided as main components. The casing 1 is an oil pump 5
Which forms a fixed side member for directly connecting the oil supply pipe 50 from the above, and is formed in a substantially cylindrical shape having the flow passage 10 therein, and the downstream side opening portion of the flow passage 10 is a rotary pipe shaft. 2 is formed in a large-diameter bearing hole 11 for axial support, an oil supply joint 12 for connecting an oil supply pipe 50 is integrally formed on the upstream side, and the outer opening of the oil supply joint 12 is connected to the oil supply port. 13 is said.

A seal hole 14 for mounting the floating sheet 3b is formed on the upstream side of the flow path 10. A valve seat 40 is formed in the seal hole 14 with its upstream opening edge protruding inward, and an annular groove 41 is provided adjacent to the downstream side of the valve seat 40.

An oil drain port 15 is formed in the side wall of the bearing hole 11, and an oil drain pipe 5 is installed in the oil drain port 15.
2 is connected, and the tip of the oil drain pipe 52 is connected to the oil tank 5
I am trying to connect to 3.

The rotary tube shaft 2 constitutes a rotary member for connecting to the motor main shaft 6 side, is formed in a substantially cylindrical shape having a flow passage 20 inside, and one end thereof is It is rotatably supported by ball bearings 21 and 21 in a bearing hole 11 in the casing 1, and a seal joint portion for connecting to a motor main shaft 6 is provided at the other end of the rotary tube shaft 2. 22 is provided.

The rotary seal member 3 is a member for rotatably sealingly connecting the flow passage 10 of the casing 1 which is a stationary member and the flow passage 20 of the rotary tube shaft 2 which is a rotating member. In this embodiment, the insert seal 3a
And the floating sheet 3b. The insert seal 3a is made of ceramics in an annular shape, and is fitted to the inner end surface of the rotary tube shaft 2.

The floating sheet 3b is formed in a cylindrical shape having a communication hole 30 therein, and a flange 31 is provided on an outer peripheral surface of a midway portion thereof, and one outer peripheral surface of the floating sheet 3b with respect to the seal hole 14 in the casing 1. And an O-ring 16 and a backup ring 17 for sealing between the inner peripheral surface of the seal hole 14 and the sliding outer peripheral surface of the floating seat 3b. ing. This floating sheet 3b
A valve spool portion 42, which is in close contact with the valve seat 40, is integrally provided at one end side thereof, and a communication hole 43 for communicating between the annular groove 41 and the communication hole 30 is formed in a side wall thereof. There is.

The seal surface 32 of the insert seal 3a
An annular insert seal 3 made of a ceramic material is provided on the downstream end surface of the floating sheet 3b facing the
3 is fitted. Further, a total of four truss screws 35, the amount of screwing of which is regulated by a bush 34, are screwed into the downstream end surface of the seal hole 14 at equal intervals, and the flange 3 of the floating sheet 3b is also attached.
By mounting the sliding engagement holes 36 formed in No. 1 so as to be slidable along the bushes 34, the floating seat 3b is prevented from rotating.

A spring mounting hole 37 having a diameter larger than that of the sliding engaging hole 36 is coaxially formed on the downstream side of the sliding engaging hole 36, and an annular bottom portion 37a of the spring mounting hole 37 and a truss screw are formed. A seal release spring 38 is press-fitted between the head 35 and the back surface 35a of the head 35, and the repulsive force of the seal release spring 38 causes the floating sheet 3b to have the seal surface 33a of the insert seal 33 of the rotary tube shaft 2 side insert. The seal 3a is biased to slide in a direction away from the seal surface 32. The seal releasing spring 38, the valve spool portion 42 and the valve seat 40 constitute the check valve 4.

Next, the operation of this embodiment will be described. When the oil pump 5 is operated to supply the cutting oil to the oil supply port 13 of the oil supply rotary joint A, the oil supply pressure causes the valve spool portion 42 to move down the floating seat 3b against the repulsive force of the seal release spring 38. Press and slide to the side. As a result, the seal surface 33a of the insert seal 33 provided on the floating sheet 3b side is brought into pressure contact with the seal surface 32 of the insert seal 3a provided on the rotary tube shaft 2 side, and the communication hole 30 of the floating sheet 3b and the rotary tube shaft 2 are provided. And the flow path 20 of are rotatably connected. Then, at this time, the valve spool portion 42 is attached to the valve seat 40.
Since it is opened, from the oil supply port 13 through the annular groove 41, the communication hole 43, the communication hole 30, and the flow path 20 of the rotary pipe shaft 2, through the hollow portion of the motor main shaft 6 and the hollow portion of the spindle. Supplied to the drill.

Next, when the oil pump 5 is stopped and the supply of cutting oil is stopped, the oil supply pressure to the oil supply port 13 of the oil supply rotary joint A decreases, so that the seal release spring 38 repels the floating seat 3b. Is pushed and slid to the upstream side until the valve spool portion 42 comes into close contact with the valve seat 40. As a result, the insert seal 3 provided on the floating seat 3b side
The seal surface 33a of No. 3 and the seal surface 32 of the insert seal 3a provided on the rotary tube shaft 2 side are in a non-contact state, and even if the rotary seal member 3 is rotated without supplying cutting oil, heat generation and seizure of the rotary seal member 3 are prevented. it can. In addition, both sealing surfaces 33a, 3
The oil leakage due to the separation of No. 2 will be collected in the oil tank 53 from the oil discharge port 15 via the oil discharge pipe 52.

As described above, in the refueling rotary joint A in the machining center of the present embodiment, as described above, even if the oil need not be discharged, the refueling is simply stopped. Rotating seal member 3
Both sealing surfaces 33a, 32 can be automatically separated, and thus, even if the sealing surfaces 33a and 32 are rotated as they are, it is possible to prevent heat generation and seizure of the rotating seal member 3 without any special operation.

Further, since the valve spool portion 42 is integrally provided on one end side of the floating seat 3b, and the spool spring also serves as the seal releasing spring 38, the number of parts can be reduced.
Assembly and parts management are easy and cost reduction can be achieved. Further, since the valve spool portion 42 can be formed to have the same size as the flow passage 10 of the casing 1, the influence of pressure loss can be reduced even if the whole is made compact, and it is also advantageous for high speed rotation.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific structure is not limited to this embodiment, and there are design changes and the like within the scope not departing from the gist of the present invention. Also included in the present invention. For example, in the embodiment, the floating seat 3b is integrally provided with the insert seal 33 which is brought into pressure contact with the insert seal 3a provided on the inner end surface of the rotary tube shaft 2, but the insert seal 33 is not limited to this, and the insert seal 33 is disc-shaped. The reinforcing sheet may be fixed to the reinforcing sheet, and the reinforcing sheet may be mounted between the floating sheet 3b and the rotary tube shaft 2 so as to be urged by a spring to the upstream side together with the reinforcing sheet. The floating sheet 3b may have any shape. Is.

[0020]

As described above, the rotary joint for refueling of the present invention has the above-mentioned structure,
It is possible to prevent both heat generation and seizure by separating both seal surfaces of the rotary seal member simply by stopping the fuel supply. Also,
With a simple structure, the number of parts is small, assembly and parts management are easy, and cost can be reduced. Further, even if the check valve is made large, there is an effect that it can be formed in a compact size that does not affect the outer shape and is advantageous for high-speed rotation.

[Brief description of drawings]

FIG. 1 is a sectional view showing an oil supply rotary joint according to an embodiment of the present invention in a state where hydraulic pressure is applied.

FIG. 2 is a cross-sectional view showing a refueling rotary joint in a state in which the above hydraulic pressure is not applied.

[Explanation of symbols] A Rotary joint for refueling 1 Casing 2 Rotating pipe shaft 3 Rotating seal member 3a Insert seal 3b Floating seat 4 Check valve 10 Flow path in casing 14 Seal hole 20 Flow path in rotating pipe shaft 30 Floating seat Communication hole 33 Insert seal 38 Seal release spring 40 Valve seat 42 Valve spool

Claims (1)

[Claims] 1. A casing having a flow channel in the axial direction on the fixed side, a rotary tube shaft having a flow channel in the axial direction on the rotating side rotatably supported in the casing, and A floating sheet that is slidably mounted in the axial direction of the seal hole formed in the flow path of the casing and is rotatably seal-connected with an insert seal provided on the inner end surface of the rotary tube shaft by fluid pressure. And a check valve provided in the casing for opening a flow path of the casing by fluid pressure, and mounted between the casing and the floating seat to slide the floating seat in a direction in which a sealing surface of the floating seat separates from a sealing surface of the insert seal. A rotary joint for refueling, comprising a seal releasing spring for dynamically urging the valve spool portion of the check valve. Together are formed integrally with the seal bore attached tip of Ngushito,
A rotary joint for refueling, characterized in that a valve seat is formed at the upstream opening edge of the seal hole.