JPH0746861Y2 - Rotary joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a rotary joint used when supplying a coolant into a spindle of a machine tool.

(Prior Art) In a machine tool for a machining center, in order to cool the cutting heat during machining, a rotation-side coolant liquid flow path is formed inside the spindle, and is fixed to this rotation-side coolant liquid flow path via a rotary joint. The coolant liquid can be supplied by connecting the side coolant liquid flow path.

As this type of rotary joint, conventionally, for example,
A rotary tube shaft fixed to the rear end of the spindle, and a floating sheet axially slidably supported by the joint body, and a rotation side flow path of the rotary tube shaft formed inside the spindle. Side of the floating sheet, the fixed side flow path of the floating sheet is connected to the fixed side coolant liquid flow path formed inside the joint body, and the floating sheet slides forward to float the floating sheet. By contacting the seal surface of the rotary tube shaft with the seal surface, it is known that the fixed side flow path and the rotary side flow path are connected, and in this case, the rotary tube shaft is The front end is fixed to the rear end of the spindle, and the rear end is supported by a ball bearing shaft support with respect to the joint body.

(Problems to be solved by the invention) However, if the rear end of the rotary tube shaft is supported by the shaft supporting portion by the ball bearing with respect to the joint body as in the conventional case, the spindle is set by the amount corresponding to the setting of the shaft supporting portion. The length of the rear end side protruding from the rear end portion is increased.

As described above, when the length of the rear end side of the rotary tube shaft protruding from the rear end of the spindle becomes long, the joint body needs to be formed correspondingly, and the rotary joint becomes large. was there.

Further, in the case where the spindle rotates at a high speed of 10,000 rotations or more, there is a problem that a shake occurs on the rear end side of the rotary tube shaft, vibrations and loads occur on the shaft support portion, and troubles such as breakage easily occur.

The present invention focuses on the above-mentioned conventional problems and adopts a structure in which the shaft support portion is not provided on the rotary pipe shaft, so that the length of the rear end side of the rotary pipe shaft protruding from the rear end portion of the spindle is reduced. An object of the present invention is to provide a rotary joint that can be shortened, is compact and has a simple structure, and can prevent troubles due to runout.

(Means for Solving the Problems) In order to solve the above problems, in the rotary joint of the present invention, the rotary tube shaft having the rotation-side flow passage formed therein and the fixed-side flow passage formed therein are formed. A seat joint part including a floating seat is formed inside the joint body, and the rotary pipe shaft is fixed to a rear end of a spindle in which a rotation side coolant liquid flow path is formed, and at the A side flow path communicates with the rotation side coolant liquid flow path,
And the rear end surface of the rotary tube shaft is formed on the rotary side sealing surface, and the floating sheet is axially slidably supported by the joint body in which the fixed side coolant liquid flow path is formed, and The fixed-side flow passage communicates with the fixed-side coolant liquid flow passage, the front end surface of the floating sheet is formed as the fixed-side seal surface, and the floating sheet slides forward to fix the fixed-side seal surface to the rotary-side seal. In a rotary joint in which the fixed-side flow passage and the rotation-side flow passage are connected to each other by abutting against the surface, in a cantilever state in which the rotary pipe shaft does not have a shaft supporting portion with respect to the joint body, the front end portion of the spindle is The structure is fixed to the rear end.

(Operation) In the rotary joint of the present invention, the coolant liquid flows from the fixed-side coolant liquid passage formed in the joint body, through the seal joint portion, and into the rotation-side coolant liquid passage formed inside the spindle, It is supplied to the processing part from the tip of the spindle for cooling the cutting heat.

At the time of supplying this coolant liquid, the flow path on the rotating side of the rotary tube shaft that constitutes the seal joint section and the flow path on the fixed side of the floating sheet communicate with each other. In this case, the floating sheet slides forward, The fixed-side sealing surface of the floating sheet contacts the rotating-side sealing surface of the rotary tube shaft, thereby connecting the fixed-side flow path and the rotating-side flow path.

In this rotary joint, the front end portion is fixed to the rear end portion of the spindle in a cantilevered state in which the rotary tube shaft has no shaft supporting portion with respect to the joint body.

Therefore, the length of the rotary tube shaft protruding from the rear end portion of the spindle can be shortened by the amount that does not have the shaft supporting portion, and the joint body can be shortened accordingly, so that the whole can be formed compactly. At the same time, the structure can be simplified due to the absence of the shaft supporting portion, and since the runout on the rear end side of the rotary tube shaft becomes small, troubles such as vibration can be prevented.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view showing a rotary joint of the first embodiment. In this rotary joint, a seal joint portion 3 having a rotary pipe shaft 1 and a floating seat 2 is formed inside a joint body 4.

The rotary tube shaft 1 has a rotary side flow passage 10 formed therein, and a seal ring 12 forming a rotary side sealing surface 11 is fitted to a rear end face of the rotary pipe shaft 1.

The rotary tube shaft 1 is fixed to the rear end of the spindle 5, and in this case, a rotation-side coolant liquid flow path 50 is formed inside the spindle 5, and the rotation-side coolant liquid flow path 50 The front end portion of the rotary tube shaft 1 is screwed into the screw hole 51 formed at the end portion, so that the rotary tube shaft 1 is cantilevered with respect to the joint body 4 in a cantilevered state, and the front end portion is Is fixed to the rear end of the spindle 5, and the internal rotation side flow passage 10 is connected to the rotation side coolant liquid flow passage 50.

The floating sheet 2 has a fixed-side flow passage 20 formed inside, a flange 21 formed on the outer periphery, and a seal ring 23 forming a fixed-side sealing surface 22 is fitted to the front end surface.

The floating sheet 2 is slidably supported in the seal hole 40 formed in the joint body 4 in the axial direction, and the internal fixed-side flow passage 20 is formed in the joint body 4. Check valve in channel 41
It is communicated via 24.

The check valve 24 is an upstream opening of the fixed-side flow passage 20, and is normally urged to the upstream side by a spring 25 so as to close the fixed-side flow passage 20.
The fixed-side flow passage 20 communicates with the fixed-side coolant liquid flow passage 41 by being pushed down to the downstream side to open.

Further, the floating sheet 2 is prevented from rotating in the rotation direction by inserting the guide pin 42 fixed to the joint body 4 into the guide hole 26 formed in the flange 21, and is attached to the guide pin 42. Spring 43
It is always biased backwards by. The spring 43 is set to have a weaker elastic force than the spring 25 of the check valve 24 described above.

The joint body 4 has a storage space 44 for the seal joint portion 3 formed therein and a front end portion fixed to a rear end surface of the spindle cover 6.

Reference numeral 7 in the drawing denotes a rotary pipe shaft cover, and a labyrinth seal portion 70 is formed between the rotary pipe shaft cover 1 and the rotary pipe shaft 1.

Next, the operation of this embodiment will be described.

When the coolant liquid is supplied to the fixed side coolant liquid flow path 41, the liquid pressure is applied to the floating seat 2, the floating seat 2 slides in the forward direction against the spring 43, and the fixed side seal surface 22 is formed. The fixed side flow passage 20 and the rotation side flow passage 10 are connected to each other by contacting the rotation side sealing surface 11. Then, the check valve 24 is opened against the spring 25 by the hydraulic pressure of the coolant liquid, the coolant liquid flows from the fixed-side coolant liquid flow passage 41 into the fixed-side flow passage 20, and further the rotation-side flow passage 10 is passed. After that, the coolant flows through the rotation-side coolant liquid flow path 50 and is supplied from the tip end portion of the spindle 5 to the processing portion for cooling the cutting heat.

As described above, in this embodiment, the fixed side flow passage 20 and the rotation side flow passage 10 can be connected and the check valve 24 can be opened by the hydraulic pressure of the coolant itself.

Further, in this rotary joint, the front end is fixed to the rear end of the spindle 5 in a cantilever state in which the rotary tube shaft 1 does not have a shaft supporting portion with respect to the joint body 4.

Therefore, the length of the rotary tube shaft 5 protruding from the rear end portion of the spindle 5 can be shortened because the shaft support portion is not provided, and the joint body 4 can be shortened by that amount, so that the entire body is made compact. In addition, the structure can be simplified because there is no shaft supporting portion, and since the runout on the rear end side of the rotary tube shaft 1 is reduced, the occurrence of troubles such as vibration can be prevented.

Next, FIG. 2 shows the rotary joint of the second embodiment.

In the second embodiment, the check valve is omitted in the fixed side flow passage 20 of the floating seat 2, and the floating seat 2 is biased forward by the spring 9.

Therefore, since the floating sheet 2 is biased in the forward direction, the fixed side seal surface 22 is always in contact with the rotary side seal surface 11, and the fixed side flow path 20 and the rotary side flow path 10 are always connected. .

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration of the present invention is not limited to the above embodiments.

(Effect of the Invention) As described above, in the rotary joint of the present invention, since the rotary tube shaft does not have the shaft supporting portion, the length protruding from the rear end portion of the spindle can be shortened,
Since the joint body can be shortened by that much, the overall structure can be made compact, and the structure can be simplified because there is no shaft support.

Further, when the rotating tube shaft is shortened, the runout on the rear end side becomes small, so that it is possible to obtain the effect that troubles such as vibration can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing a rotary joint of the first embodiment, and FIG. 2 is a sectional view of a main part showing a rotary joint of the second embodiment. 1: Rotating tube axis 10: Rotating side flow passage 11: Rotating side sealing surface 2: Floating seat 20: Fixed side flow passage 22: Fixed side sealing surface 3: Seal joint part 4: Joint body 41: Fixed side coolant liquid flow passage 5: Spindle 50: Rotating side coolant flow path

Claims (1)

[Scope of utility model registration request] 1. A seal joint portion having a rotary tube shaft having a rotation-side flow passage formed therein and a floating sheet having a fixed-side passage formed therein is formed inside a joint body, The tube shaft is fixed to the rear end of the spindle in which the rotation side coolant liquid flow passage is formed, and the rotation side flow passage inside is connected to the rotation side coolant liquid flow passage,
And the rear end surface of the rotary tube shaft is formed on the rotary side sealing surface, and the floating sheet is axially slidably supported by the joint body in which the fixed side coolant liquid flow path is formed, and The fixed-side flow passage communicates with the fixed-side coolant liquid flow passage, the front end surface of the floating sheet is formed as the fixed-side seal surface, and the floating sheet slides forward to fix the fixed-side seal surface to the rotary-side seal. In a rotary joint in which the fixed-side flow passage and the rotation-side flow passage are connected to each other by abutting against the surface, in a cantilever state in which the rotary pipe shaft does not have a shaft supporting portion with respect to the joint body, the front end portion of the spindle is A rotary joint that is fixed to the rear end.