JPH0811036A - Machine tool with fluid supply joint - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent heat generation, coolant leakage, etc. even when the spindle rotation speed is high, and to prevent a decrease in coolant supply flow rate because there is no limit on the rotation speed of the tool holder. [Structure] The coolant liquid supplied to the fluid supply hole 39 of the joint housing 31 is supplied to the tool gripping side through the radial fluid passage 29 of the tool holder 9 and the fluid supply hole 27. Dynamic pressure is generated in the coolant liquid flowing into 81 by the rotation of the dynamic pressure generating grooves 75 and 79, and most of it is returned to the radial fluid supply passage 29 side. The remaining fluid fills the leaked fluid pressure drop chamber 83. Since the volume of the leaked fluid pressure drop chamber 83 is sufficiently larger than the volume of the pump chamber 77, the pressure of the fluid is lowered to the atmospheric pressure, the fluid filled in the leaked fluid pressure drop chamber 83 is discharged to the outside through the drain hole 85, and the rotary shaft is rotated. It does not flow to the 1 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool having a fluid supply joint for supplying a fluid to a tool holder mounted on a spindle or the like.

[0002]

2. Description of the Related Art A conventional fluid supply joint for a tool holder is, as shown in FIG. 3, an inner surface of a joint housing 104 which is rotatably loosely fitted by a bearing 102 to an outer peripheral portion of a tool holder 100 on a tool gripping side. The inner surface recessed portion 10
The fluid leaking from 6 is sealed. And
The fluid passage 11 is filled with the coolant pressurized by a pump (not shown) from the coolant supply arm 110 through the fluid passage 112 provided in the joint housing 104 into the inner surface concave portion 106 and is bored in the tool holder 100.
The liquid is supplied to the liquid supply hole 120 formed at the center of the tool 118 via 4 and 116.

[0003]

However, when the rotational speed of the main shaft is increased, the seal material is excessively worn, heat is generated, coolant leaks, and the like, and the rotational speed is limited by the seal material. was there. Further, there is a problem that the leaked coolant enters the bearing between the tool holder and the joint housing, and the bearing becomes dirty or damaged.

Further, since the coolant is supplied in the radial direction, it is easily affected by the centrifugal force due to the rotation of the main shaft, and the flow rate of the coolant supply decreases at the time of high speed rotation, resulting in a decrease in the ejection amount from the tool.

The present invention has been made in order to solve the above-mentioned problems, and generates heat even if the rotation speed of the main shaft is high.
There is no leakage, there is no limit on the number of rotations,
It is an object of the present invention to provide a fluid supply joint for a tool holder in which the bearing is not contaminated or damaged, and further, the coolant supply flow rate does not decrease.

[0006]

In order to achieve this object, a machine tool having a fluid supply joint according to claim 1 of the present invention is detachably gripped coaxially with a rotary shaft and a tool gripping side. From the end of the tool holder to the outer end surface of the tool holder, and the tool holder is rotatably arranged with respect to the tool holder. It is arranged between the tool housing and the joint housing in which a fluid supply hole facing the fluid passage of the tool holder is formed for supplying, and leaks from the connecting portion of the fluid supply hole and the fluid passage. Pump means for pushing the fluid back into its connection.

According to a second aspect of the present invention, there is provided a machine tool having a fluid supply joint, wherein the pump means is formed with a spiral dynamic pressure generating groove, and the dynamic pressure generating ring is fixedly arranged on the tool holder. And a joint housing flange portion formed in the joint housing so as to be arranged to face the groove.

A machine tool having a fluid supply joint according to a third aspect of the present invention is detachably gripped coaxially with a rotary shaft, extends from the tool gripping side along the axial center, and extends from the end point to the outer end surface. A tool holder in which a fluid passage opening toward the tool holder is formed, and a fluid supply that is rotatably arranged with respect to the tool holder and that opposes the fluid passage of the tool holder to supply fluid to the fluid passage of the tool holder. A joint housing having a hole formed therein, a fluid leakage hole for communicating the fluid supply hole and the fluid passage, and a fluid leakage pressure drop chamber for reducing the pressure of the fluid leaked from the fluid passage, and the fluid leakage pressure drop chamber. And a drain hole for discharging the leaked fluid whose pressure has dropped to the outside of the joint housing.

Further, a machine tool having a fluid supply joint according to a fourth aspect is detachably gripped coaxially with a rotary shaft, extends from the tool gripping side along the axis, and extends from the end point to the outer end surface. A tool holder in which a fluid passage opening toward the tool holder is formed, and a fluid supply that is rotatably arranged with respect to the tool holder and that opposes the fluid passage of the tool holder to supply fluid to the fluid passage of the tool holder. A joint housing having a hole formed therein, and pump means arranged between the tool holder and the joint housing for pushing back the fluid leaking from the connecting portion of the fluid supply hole and the fluid passage to the connecting portion. , A leaking fluid pressure drop chamber communicating with the pump means for dropping the pressure of the fluid leaked from the pump means, and an opening in the leaking fluid pressure drop chamber for reducing the pressure. It was leakage fluid and a drain hole for discharging to the outside of the joint housing.

[0010]

In the machine tool having the fluid supply joint according to claim 1 of the present invention having the above structure, the joint housing supplies the fluid from the fluid supply hole to the fluid passage of the tool holder, and the pump means supplies the fluid. The fluid leaked from the connecting portion between the hole and the fluid passage is pushed back to the connecting portion.

In the machine tool having the fluid supply joint according to the second aspect, the dynamic pressure generating ring in which the spiral dynamic pressure generating groove is formed rotates together with the tool holder, and the fluid leaked from the connecting portion is removed. Push back to the connecting part.

Further, in a machine tool having a fluid supply joint according to a third aspect of the invention, the joint housing supplies fluid from the fluid supply hole to the fluid passage of the tool holder, and the leaked fluid pressure drop chamber and the fluid supply hole and the fluid supply hole. The pressure of the fluid that has leaked from the portion connected to the passage is reduced, and the drain hole discharges the leaked fluid having the reduced pressure to the outside of the joint housing.

Further, in a machine tool having a fluid supply joint according to a fourth aspect, the joint housing supplies fluid from the fluid supply hole to the fluid passage of the tool holder, and the pump means connects the fluid supply hole and the fluid passage. The fluid leaked from the connecting portion is pushed back to the connecting portion, the leak fluid pressure drop chamber drops the pressure of the fluid leaked from the pump means, and the drain hole discharges the leaked fluid having the lowered pressure to the outside of the joint housing.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a fluid supply joint portion to a tool holder of the machine tool of this embodiment. In the figure, a rotary shaft 1 such as a main shaft of a machine tool is rotatably supported by a housing 5 via a bearing 3. Rotary axis 1
A tapered concave portion 7 is formed in the groove, and the tapered convex portion 11 of the tool holder 9 is fitted therein. Further, a pull stud 13 is screwed onto the upper end of the tool holder 9 in the drawing. The pull stud 13 is arranged in the rotary shaft 1 and is pulled by a draw bar 15 which is urged upward in the drawing by a pulling mechanism (not shown) to fasten the tool holder 9 to the rotary shaft 1.

A small-diameter tapered recess 17 is formed at the lower end of the tool holder 9, and a collet 19 is fitted in the small-diameter tapered recess 17 and fixed to the tool holder 9 by a tightening nut 21. ing. A tool 23 is held at the center of the collet 19. Tool 23
A fluid supply hole 25 is bored at the center of the tool holder and communicates with a tool holder fluid passage 27 drilled in the tool holder 9. At the end of the tool holder fluid passage 27, a plurality of radial fluid passages 29 are bored in communication with the tool holder fluid passage 27.

On the outer periphery of the tool holder 9, a joint housing 31 is rotatably mounted on the tool holder 9 to support the bearing 3.
It is supported by 3. A joint housing flange portion 35 is arranged on the inner peripheral portion of the joint housing 31 so as to face the radial fluid passage 29. An annular recess 37 is formed on the side surface of the joint housing flange portion 35, and a fluid supply hole 39 is formed in connection with the annular recess 37. The end portion of the fluid supply hole 39 communicates with the end surface of the pin slide hole 43 opened from the main shaft side end surface 41 of the joint housing 31. In the pin slide hole 43,
The fluid supply pin 45 is slidably inserted in the axial direction, and is biased toward the rotary shaft 1 by a spring 47.

Further, the O-ring 49 has a pin slide hole 4
The fluid is prevented from leaking through the gap between the fluid supply pin 45 and the fluid supply pin 45. One end of the fluid supply pin 45 is inserted into a rotation stop hole 51 provided in the housing 5. A fluid passage 53 penetrates through the center of the fluid supply pin 45,
By communicating with the housing fluid passage 55 formed in the housing 5, the fluid can be supplied from the housing 5 side to the fluid supply hole 39 of the joint housing 31. Fluid passage 53
Check valves 57 and 59 are provided at the end of the housing and the end of the housing fluid passage 55 to prevent the fluid from leaking to the outside when the tool holder is attached and detached.

A positioning arm 61 is fixed to the outer peripheral portion of the fluid supply pin 45, and the positioning arm 61 is fitted with a notch 63 provided on the outer peripheral surface of the tool holder 9 so that the tool holder can be detached when the tool holder is attached or detached. 9 and the joint housing 31 are prevented from rotating and being out of phase. The positioning arm 61 is configured to be removed from the cutout portion 63 when the tool holder 9 is rotated.

The dynamic pressure generating ring 65 is fixed to the first small diameter portion 69 of the tool holder 9 so as to face the side surface of the joint housing flange portion 35 arranged in the joint housing 31 on the rotary shaft 1 side (upper side in the figure). Has been done. Further, the dynamic pressure generation ring 71 is fixed to the second small diameter portion 73 of the tool holder 9 so as to face the side surface of the joint housing flange portion 35 on the tool 23 side (lower side in the drawing). Then, on the surface of the dynamic pressure generating ring 65 facing the joint housing flange portion 35, as shown in FIG. 2 (a sectional view taken along the line AA of FIG. 1),
A plurality of spiral dynamic pressure generating grooves 75 are formed, and when the dynamic pressure generating ring 65 rotates counterclockwise, the coolant liquid is pushed back toward the center thereof.
That is, the convex portion of the dynamic pressure generation ring 65 forms a first pump chamber 77 that maintains a minute gap with the joint housing flange portion 35 to generate a dynamic pressure effect.

Similarly, a plurality of spiral dynamic pressure generating grooves 79 are formed on the surface of the dynamic pressure generating ring 71 facing the joint housing flange portion 35, and the convex portions thereof are the same as those of the joint housing flange portion 35. A second pump chamber 81 is formed which maintains a minute gap and produces a dynamic pressure effect.

Then, these pump chambers 77 and 81 are
It constitutes the pump means of the present invention.

Adjacent to the first pump chamber 77, a leaked fluid pressure drop chamber 83 is formed between the inner peripheral portion of the joint housing 31 and the outer peripheral portion of the dynamic pressure generating ring 65, and the outer peripheral portion of the joint housing 31 is formed. A drain hole 85 opening to the above is formed so as to communicate with the leaked fluid pressure drop chamber 83. further,
The dynamic pressure generating ring 6 is provided adjacent to the leaked fluid pressure drop chamber 83.
A small gap 91 that constitutes a labyrinth seal is provided by the large diameter portion 87 of 5 and the small diameter portion 89 of the joint housing 31. Further, a second leaked fluid pressure drop chamber 93 is formed adjacent to the minute gap 91, and a second drain hole 95 opening to the outer peripheral portion of the joint housing 31 is formed in communication with the second leaked fluid pressure drop chamber 93. Has been done.

On the other hand, an end plate 97 is arranged on the end surface of the joint housing 31 on the tool 23 side, and a minute gap 99 which constitutes a labyrinth seal is provided by the dynamic pressure generating ring 71 and the end plate 97.

The operation will be described based on the above configuration.

A fluid such as a coolant is supplied from the housing fluid passage 55 of the housing 5. When the tool is replaced, the tapered concave portion 7 of the rotary shaft 1 and the tapered convex portion 11 of the tool holder 9 are fitted together, and the pull stud 13 is pulled upward by the draw bar 15 in the drawing, so that the tool holder 9 is fastened to the rotary shaft 1. At the same time, the fluid supply pin 45 is inserted into the rotation stop hole 51 of the housing 5 to prevent the joint housing 31 from rotating together with the tool holder 9.

In this state, the housing fluid passage 55 communicates with the fluid passage 53 of the fluid supply pin 45, and the fluid is
It flows into the annular recess 37 via the fluid supply hole 39. Most of the fluid that has flowed into the annular recess 37 flows into the radial fluid passage 29, and then, via the tool holder fluid passage 27, is ejected to the outside from the fluid supply hole 25 formed in the tool 23.

A small part of the fluid flows into the first pump chamber 77 and the second pump chamber 81. First pump chamber 77
The fluid that has flowed into the tool has a dynamic pressure effect due to the pumping action of the spiral dynamic pressure generation groove 75 formed in the dynamic pressure generation ring 65 that rotates at a high speed together with the tool holder 9, and most of the dynamic pressure effect is generated in the annular recess 37 Is pushed back to. The remaining fluid leaks into the leaked fluid pressure drop chamber 83, is depressurized to the atmospheric pressure, and then discharged to the outside from the drain hole 85 opening in the outer peripheral portion of the joint housing 31. Further, a minute gap 91 forming a labyrinth seal is provided adjacent to the leaked fluid pressure drop chamber 83 to prevent fluid from leaking upward from the leaked fluid pressure drop chamber 83. However, when there is a fluid passing through the minute gap 91, the fluid flows into the second leaked fluid pressure drop chamber 93 and is discharged to the outside from the second drain hole 95. Does not flow to the side.

On the other hand, the fluid flowing into the second pump chamber 81 also has a dynamic pressure effect due to the pumping action of the spiral dynamic pressure generation groove 79 formed in the dynamic pressure generation ring 71 rotating at high speed. Most of it is pushed back into the annular recess 37. The remaining fluid passes through the minute gap 99 and is discharged to the tool 23 side.

[0029]

As is apparent from the above description, the machine tool having the fluid supply joint of the present invention prevents the leakage of the fluid supplied from the outside by the pump action, and therefore the rotation of the rotary shaft. Even if the number is high, it is possible to prevent heat generation, leakage, etc., and it is possible to discharge the leaked fluid to the outside, and the fluid may pollute or damage the bearing, etc. between the tool holder and the joint housing. Can be prevented.

Further, there is an effect that the number of revolutions is not limited and the coolant supply flow rate does not decrease.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a fluid supply joint portion of a machine tool according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a shape of a dynamic pressure generating groove in the dynamic pressure generating ring of the fluid supply joint.

FIG. 3 is a sectional view showing a configuration of a conventional fluid supply joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotary shaft 9 tool holder 25 fluid supply hole 27 tool holder fluid passage 29 radial fluid passage 31 joint housing 35 joint housing flange portion 39 fluid supply hole 65 dynamic pressure generating ring 71 dynamic pressure generating ring 75 dynamic pressure generating groove 77 first Pump chamber 79 Dynamic pressure generating groove 81 Second pump chamber 83 Leakage fluid pressure drop chamber 85 Drain hole 93 Second leak fluid pressure drop chamber 95 Drain hole

Claims (4)

[Claims] 1. A tool holder, which is detachably gripped coaxially with a rotation shaft, extends along an axis from a tool gripping side, and has a fluid passage formed to open from an end point thereof toward an outer end surface. A joint housing that is rotatably arranged with respect to the tool holder and in which a fluid supply hole facing the fluid passage of the tool holder for supplying fluid to the fluid passage of the tool holder is formed; A fluid which is arranged between the joint housing and provided with pump means for pushing back the fluid leaked from the connecting portion of the fluid supply hole and the fluid passage to the connecting portion. A machine tool having a supply joint. 2. The pump means is provided with a dynamic pressure generating groove having a spiral shape and is fixed to the tool holder, and the coupling is arranged so as to face the dynamic pressure generating groove. A machine tool having a fluid supply joint according to claim 1, which is formed of a joint housing flange portion formed on the housing. 3. A tool holder, which is detachably gripped coaxially with a rotation shaft, which extends along the axis from the tool gripping side, and which has a fluid passage opening from its end point toward the outer end surface. A joint housing that is rotatably arranged with respect to the tool holder and has a fluid supply hole facing the fluid passage of the tool holder for supplying fluid to the fluid passage of the tool holder; A leakage fluid pressure drop chamber for communicating with the connection portion between the fluid passage and the fluid passage and for reducing the pressure of the fluid leaked from the connection portion, and a leakage with the pressure dropped to the leakage fluid pressure reduction chamber. A machine tool having a fluid supply joint, comprising: a drain hole for discharging fluid to the outside of the joint housing. 4. A tool holder, which is detachably gripped coaxially with a rotation shaft, extends along an axis from the tool gripping side, and has a fluid passage formed to open from its end point toward the outer end surface. A joint housing that is rotatably arranged with respect to the tool holder and in which a fluid supply hole facing the fluid passage of the tool holder for supplying fluid to the fluid passage of the tool holder is formed; Pump means arranged between the joint housing and for pushing back the fluid leaked from the connecting portion of the fluid supply hole and the fluid passage to the connecting portion, and a pump means communicating with the pump means. A leak fluid pressure drop chamber for reducing the pressure of the fluid leaked from the means, and a leak fluid whose pressure has dropped, which is opened in the leak fluid pressure drop chamber, Machine tool having a fluid supply coupling, characterized in that and a drain hole for discharging to the outside.