JPH11221767A - Coolant feeding device for double-head surface finishing processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coolant feeding device for double-head surface finishing processor which can feed the coolant to a grinding surface without giving any influence in the coolant feeding even though the rotating number of a surface plate is increased, and can feed the coolant positively by utilizing a centrifugal force generated by rather increasing the rotating number. SOLUTION: This coolant feeding device has a coolant pipe 20 set in the hollow part 13 of a sun gear 11 a discharge part 23 formed by opening the tip of the coolant pipe 20 at the upper side of the sun gear 10, and a pocket 30 provided on a lower surface plate 6, and to store a part of the coolant discharged from the discharge part 23. The coolant 19 is fed to a work W from the outer periphery at the upper side of the sun gear 10, during the grinding of the work W, and the coolant 19 in the pocket 30 is fed to the work W by rising its liquid level by a centrifugal force, so as to cool the work W sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coolant supply device for a two-head flat finishing machine known as a so-called lapping machine, and in particular, to supply a coolant to a grinding surface of a grinding wheel to cool a work, and The present invention relates to a coolant supply device that performs grinding while cleaning.

[0002]

2. Description of the Related Art Generally, a two-head flat finishing machine is shown in FIG.
As shown in the above, the upper grinding stone 101 and the lower grinding stone 111 which are annular disks are arranged at intervals vertically so that their axes coincide, and the upper grinding stone 101 and the lower grinding stone 111 are rotated in directions opposite to each other, Work W installed on lower whetstone 111
The upper grindstone 101 moves downward as indicated by an arrow A, and presses the upper grindstone 101 against the upper surface of the work W, whereby both surfaces of the work W are ground by the upper grindstone 101 and the lower grindstone 111. ing. Upper whetstone 101 and lower whetstone 11
In 1, an upper spindle 102 attached to an upper stool 100 and a lower spindle 112 attached to a lower stool 110 are normally driven to rotate in opposite directions by a motor or the like (not shown). The upper spindle 102 is an upper spindle head 103
The lower spindle 112 is rotatably supported by the lower headstock 113.
It is supported rotatably. 114 is sun gear and 1
Reference numeral 15 denotes a sun gear shaft. A work holder (not shown) meshes with the sun gear 114, and the work holder also meshes with an inner peripheral gear (not shown) so that the work holder performs planetary motion by driving the sun gear 114 to rotate. .

[0003] In the grinding of a work such as a semiconductor wafer, the heat of the grinding causes systematic deformation, grinding burn, grinding cracks, residual stress, and the like. For this reason, it is necessary to supply coolant to the ground surface in order to remove the grinding heat during the grinding as much as possible.

Conventionally, as can be seen from FIG. 3, a coolant (coolant) 108 is supplied to a toyo 105 from a nozzle 106 fixed above the upper headstock 103, and further, a pipe 1
The coolant 108 is supplied to the ground surface of the work W via the reference numeral 07. Although the nozzle 106 is fixed to the upper headstock 103 and does not rotate, the toyo 105 is attached to the bracket 104 of the upper platen 100,
5 and the pipe 107 rotate together with the upper stool 100. Further, the pipe 107 is embedded in the upper surface plate 100 and the upper grindstone 101, and the coolant 108 is dropped from the upper grindstone 101 and supplied onto the work W if there is no influence of the centrifugal force due to the rotation of the upper surface plate 100. . Then, the coolant 108 supplied to the grinding surface cools the work W, and is collected in the coolant collecting tub 117 from the plurality of drain holes 116 formed in the lower platen 110.

[0005]

However, the conventional coolant supply apparatus has the following disadvantages. 1. Ring-shaped toyo 10 that rotates together with upper surface plate 100
The coolant 108 is supplied from the upper surface plate 100 side to the ground surface, which is a processing portion, by its own weight via the pipe 107 via the pipe 107. Therefore, when the rotation speed of the upper surface plate 100 is increased, the pipe 108 is affected by centrifugal force. It becomes difficult for the coolant 108 to flow downward in the interior 107, so that a sufficient coolant 108 is not supplied to the work W. Therefore, the grinding heat is accumulated in the work W, which causes systematic deformation of the work W, grinding burn, grinding cracks, residual stress, etc., and also causes early clogging of the grindstone, and the dimensional accuracy of the work W varies. Cause various troubles. 2. Even if the coolant 108 flows downward in the pipe 107, the coolant 108 scatters radially outward due to centrifugal force and is not effectively supplied to the ground surface. 3. It is difficult to incorporate a device for increasing the supply pressure of the coolant 108 or supplying a large amount of the coolant 108 to the grinding surface on the upper surface plate 100 side, and even if these devices can be incorporated, these devices are incorporated. Therefore, there are problems such as preparing an expensive device and complicating the structure.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to increase the rotation speed of a surface plate without affecting the supply of coolant at all, but rather utilizing the centrifugal force generated by increasing the rotation speed. It is an object of the present invention to provide a coolant supply device for a two-head flat finishing machine, in which coolant is supplied to a ground surface.

[0007]

In order to achieve this object, a coolant supply device according to the present invention comprises a rotatable upper plate having a circular upper grindstone coaxially mounted on a lower surface thereof, and a rotatable upper plate below the upper plate. A rotatable lower surface plate having a coaxially mounted upper lower whetstone and an annular lower whetstone coaxially mounted on the upper surface thereof, and the upper whetstone and the lower whetstone on the inner peripheral side of the upper whetstone and the lower whetstone. A rotatable sun gear provided coaxially, an inner peripheral gear rotatable coaxially with the sun gear, and an outer gear provided between the sun gear and the inner peripheral gear and meshing with the sun gear and the inner peripheral gear. In a coolant supply apparatus for a two-head flat finishing machine having a plurality of work holders having gears, a non-rotating coolant pipe is provided through the lower platen and the axis of the sun gear, and a pump for supplying coolant is provided. Connect to the coolant pipe and At the upper end of the port pipe, an outlet for discharging the coolant to the upper surface of the sun gear is provided, and a cup-shaped pocket receiving the coolant from the outlet is formed coaxially with the lower platen on the upper surface of the lower platen, A coolant is supplied to the work from the outlet through the upper surface of the sun gear, and a coolant received in the pocket is supplied to the work by centrifugal force generated by rotation of the lower platen.

A coolant guard for covering the upper grindstone, the lower grindstone and the lower platen and receiving coolant from the outer periphery of the work holder and the pocket; and a drain hole provided in a circumferential direction of the lower platen. And a lid provided on the bottom surface of the pocket, communicating with the drain hole, having a smaller diameter than the drain hole, and restricting a flow rate of coolant from inside the pocket to the coolant guard. And a coolant recovery section comprising:

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic front view of a two-head flat finishing machine incorporating a coolant supply device according to the present invention, and shows a main part in cross section.
FIG. 2 is a longitudinal sectional view showing a coolant discharge section and a recovery section.

Reference numeral 1 denotes an upper surface plate on which an annular upper grindstone 2 is mounted on a lower end surface thereof. An upper spindle 3 is coaxially mounted on the upper surface plate 1 at the center of the upper surface on the opposite side of the upper grindstone 2. The upper spindle 3 is rotatably supported by an upper headstock 4. ing. Although not shown, the upper spindle 3
Is rotationally driven by a motor or the like provided on the upper headstock 4. Thus, the upper surface plate 1 and the upper grindstone 2 are driven to rotate together with the upper main shaft 3. Reference numeral 6 denotes a lower stool, which is arranged below the upper stool 1 so as to be coaxial with and opposed to the lower stool 1. An annular lower grindstone 7 having substantially the same inner diameter as the upper grindstone 2 is coaxially mounted on the upper surface of the lower grindstone 6, and the upper grindstone 2 and the lower grindstone 7 are coaxial and have a predetermined shape. They are arranged to face each other at intervals. Lower surface plate 6
A lower spindle 8 is attached through the center of the lower spindle 8, and the lower spindle 8 is rotatably supported by a lower headstock 9. Although not shown, the lower spindle 8 is also driven by a motor or the like.
It is driven to rotate in the opposite direction. Thus, the lower grindstone 7 is driven to rotate together with the lower surface plate 6. Accordingly, the upper grindstone 2 and the lower grindstone 7 rotate in opposite directions. For example, when the upper grindstone 2 rotates clockwise, the lower grindstone 7 rotates counterclockwise.

Reference numeral 10 denotes a sun gear, and 11 denotes a sun gear shaft. The sun gear shaft 11 penetrates the lower main shaft 8 and the bearing 1
2 rotatably supported on the lower main shaft 8. The gear 14 attached to the lower end of the sun gear shaft 11 is a motor 16
The sun gear shaft 11 is rotationally driven by meshing with the gear 15 of FIG.

The sun gear 10 is disposed on the inner periphery of the upper grindstone 2 and the lower grindstone 7 and meshes with an external gear 38 formed on the outer periphery of the work holder 17 as in the prior art. The work holder 17 is also engaged with a peripheral gear 18 (not shown, but attached to the processing machine body), and the work holder 17 is rotated by the rotation of the sun gear 10 or the simultaneous rotation of the sun gear 10 and the inner peripheral gear 18. The planetary motion is performed around the sun gear 10 at a predetermined rotation speed. While the work W held by each work holder 17 also carries out planetary movement together with the work holder 17, the upper and lower surfaces thereof are pressed against the lower surface of the upper grindstone 2 and the upper surface of the lower grindstone 7, and both surfaces of the work W are And the lower grindstone 7.

The sun gear shaft 11 has a concentric cylindrical hollow portion 13, into which a coolant pipe 20 is inserted, and through a bearing 25 (see FIG. 2).
Is held in. Since the bearing 25 is provided, even if the sun gear 10 rotates, the coolant pipe 2
0 does not rotate.

The coolant pipe 20 has a pump 2 at its lower end.
1 is provided, and the coolant 19 in the coolant tank 22 is sucked up by driving the pump 21,
It rises in the coolant pipe 20. The upper end of the coolant pipe 20 is a discharge portion 23 for the coolant 19. As shown in FIG. 2, the discharge portion 23 has an opening 24 at the upper end of the coolant pipe 20, an inverted cup-shaped cover member 26 fixed to the center of the upper surface of the sun gear 10, and a circumferential surface on the side surface of the cover member 26. It comprises a plurality of outlets 27 open in the direction. For this reason, referring to FIGS. 1 and 2, when the pump 21 is driven, the coolant 19 rises in the coolant pipe 20 toward the discharge portion 23, and fills the space in the cover member 26 from the opening 24, Further, it flows out from the plurality of outlets 27 toward the outer periphery of the sun gear 10 as shown by the arrow D.

Reference numeral 30 denotes a pocket formed by recessing the center of the upper surface of the lower platen 6, and serves as a housing for the coolant 19. Drain holes 34 are formed in the lower surface plate 6 at a plurality of locations obliquely downward from the bottom of the pocket 30. 3
Reference numeral 5 denotes a coolant collecting tub, which is attached to the lower headstock 9 below the outlet of the drain hole 34 so as to collect the coolant 19 flowing out from the drain hole 34. A coolant guard 36 is formed above the coolant collecting tub 35 to receive the coolant 19 flowing from between the upper grindstone 2 and the lower grindstone 7. It is to be collected in a collection tub 35.

The portion connected to the drain hole 34 from the bottom of the pocket 30 has a small diameter having a diameter that allows the coolant 19 to flow out of the pocket 30 at an appropriate speed. It does not flow out of the drain hole 34. According to the present invention, as shown in FIG. 2, an annular lid 31 having a hole 32 having a small diameter as described above is attached to the bottom surface of the pocket 30 at a location corresponding to the drain hole 34.
Here, the diameter of each hole 32 is about 1/4 of the diameter of the drain hole 34. When the lower surface plate 6 rotates at a high speed by operating the two-head flat finishing machine, the coolant 19 in the pocket 30 receives centrifugal force and is brought close to the inner wall of the pocket 30 as shown in FIG. Outflow into the hole 34 is restricted. Here, the lid 31, the small-diameter hole 32, the drain hole 34, the coolant collecting tub 35, and the coolant guard 36 constitute a coolant collecting unit 33.

The operation of the present invention configured as described above will now be described.

The work W is set on the work holder 17,
This work holder 17 is placed on the lower grindstone 7 and the external gear 3
8 meshes with the sun gear 10 and the inner peripheral gear 18. Next, when the lower spindle 8 is driven to rotate at a predetermined speed, the lower platen 6 is rotated.
And the lower grindstone 7 rotates. At the same time, when the sun gear 10 is driven to rotate by the motor 16, the work holder 17 makes a planetary movement around the sun gear 10. Further, the upper spindle 3 is rotated at a predetermined speed in a direction opposite to that of the lower spindle 8 to lower the upper headstock 4 while rotating the upper stool 1 and the upper grindstone 2 so that the upper grindstone 2 is fixed on the upper surface of the work W. Contact with pressure. As a result, the work W is ground by the upper grindstone 2 and the lower grindstone 7.

During the grinding process, the coolant supply device according to the present invention operates to remove the grinding heat of the work W.
That is, the pump 21 is driven to suck up the coolant 19 from the coolant tank 22, move up the coolant pipe 20, and flow out from the discharge portion 23 to the upper surface of the sun gear 10. Here, the coolant pipe 20 is connected to the sun gear shaft 11
Is stationary in the hollow portion 13 of the lower platen 6.
Even if the sun gear 10 rotates at high speed, the coolant 19 is easily sucked up and flows out from the discharge unit 23 without being affected by any rotation (for example, the effect of centrifugal force).

The coolant 19 flowing out of the discharge section 23
Flows radially outward on the upper surface of the sun gear 10 rotated by centrifugal force generated by the rotation of the sun gear 10, most of which is supplied to the work holder 17 and the work W, and the work W
Cool the surface to be ground. On the other hand, part of the coolant 19 falls into the pocket 30. Pocket 3 like this
The coolant 19 that has fallen into the inside of the
As shown in FIG. 1, the coolant level rises due to centrifugal force and is supplied to the work holder 17 and the work W without cooling the work W to cool the ground surface of the work W.

As described above, in the prior art, the coolant is supplied from the outer peripheral portion of the lower surface of the rotating upper surface plate, so that the coolant moves radially outward of the upper surface plate by centrifugal force generated by rotation of the upper surface plate. The coolant was scattered, and the coolant was not sufficiently supplied to the work immediately below the upper surface plate and held by the work holder. And, as the rotation speed of the upper stool increases, the coolant is more strongly scattered outward in the radial direction, and the supply amount to the work is further reduced.

On the other hand, in the case of the present invention, the coolant is reliably and sufficiently supplied to the work by positively utilizing the centrifugal force. That is, a non-rotating coolant pipe 20 is provided through the center of the sun gear 10 and the lower platen 6, a pump 21 for supplying coolant is connected to a lower end of the coolant pipe 20, and an outlet 27 is provided at an upper end of the coolant pipe 20. Is formed. Then, the coolant is supplied from the outlet 27 to the upper surface of the sun gear 10, and then supplied to the inside of the work 30 placed on the work holder 17 and the pocket 30 of the lower platen 6. As the rotation speed of the sun gear 10 increases, the coolant 19 on the upper surface is subjected to a larger centrifugal force, and a larger amount reaches the work W. If the rotation of the lower platen 6 increases, the pocket 30
The inner coolant 19 is pushed up more by the centrifugal force on the inner wall of the pocket 30, and more coolant 19 is supplied to the work W. This is a significant advantage of the present invention. In addition, the present invention allows the coolant 19 to overflow from the pocket 30 toward the work W by supplying a larger amount of coolant 19 than the amount flowing out from the small-diameter hole 32. Cooling of the work is effective during processing.

The coolant 19 that has cooled the work W flows out of the outer periphery of the work holder 17 to the coolant guard 36 and is collected in the coolant collecting tub 35. When the machining is completed, the rotation of the platen stops, and the coolant 19 in the pocket 30 is collected in the coolant collecting tub 35 through the small-diameter hole 32 and the drain hole 34 of the lid 31.

[0024]

As described above, the coolant supply apparatus for a two-head flat finishing machine according to the present invention has the following effects. (1) The coolant flows out of the upper surface of the sun gear and from the upper end of the non-rotating coolant pipe at the center thereof, and further passes through the upper surface of the rotating sun gear to the work holder and the work mounted on the work holder. , Regardless of the rotation speed of the upper and lower platens. Then, as the rotation speed of the sun gear is increased, more coolant on the upper surface of the sun gear is supplied to the work holder and the work therein, so that the work can be sufficiently cooled. (2) A cup-shaped pocket is provided at the center of the upper surface of the lower stool, and the liquid level of the coolant stored therein is raised along the inner peripheral surface of the pocket according to the rotation speed of the lower stool. Accordingly, more coolant is supplied to the work in the work holder in accordance with the increase in the rotation speed of the lower platen, and the work can be surely and sufficiently cooled. (3) The amount of coolant discharged and the coolant pressure can be set only by the pump connected to the coolant pipe regardless of the centrifugal force caused by the rotation of the upper and lower platens. By supplying the coolant, the coolant overflows from the pocket to sufficiently cool the workpiece. (4) Since a required amount of coolant can be reliably supplied, grinding heat does not accumulate. Therefore, there is no occurrence of systematic deformation of the work, grinding burn, grinding cracks or residual stress, and the like. It is possible to eliminate all the conventional troubles and to process the work with high precision without causing the clogging of the grinding wheel at an early stage.

[Brief description of the drawings]

FIG. 1 is a schematic view of a two-head flat finishing machine incorporating a coolant supply device of the present invention.

FIG. 2 is a longitudinal sectional view showing a coolant discharge section and a recovery section.

FIG. 3 is a schematic longitudinal sectional view of a two-head flat finishing machine incorporating a conventional coolant supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper surface plate 2 Upper grindstone 3 Upper spindle 4 Upper headstock 6 Lower surface plate 7 Lower grindstone 8 Lower spindle 9 Lower headstock 10 Sun gear 11 Sun gear shaft 12 Bearing 13 Hollow part 14, 15 Gear 16 Motor 17 Work holder 18 Inner peripheral gear DESCRIPTION OF SYMBOLS 19 Coolant 20 Coolant pipe 21 Pump 22 Coolant tank 23 Discharge part 24 Opening port 26 Cover member 27 Outlet 30 Pocket 31 Lid 32 Small diameter hole 33 Coolant recovery part 34 Drain hole 35 Coolant recovery tub 36 Coolant guard 38 External gear W Work

Claims (2)

[Claims] 1. A rotatable upper surface plate having an annular upper grindstone coaxially attached to a lower surface thereof, and a rotatable upper surface plate provided below and below the upper surface plate and coaxially therewith. A rotatable lower surface plate having a lower grindstone attached thereto, a rotatable sun gear provided coaxially with the upper grindstone and the lower grindstone on the inner peripheral side of the upper grindstone and the lower grindstone, and a coaxial with the sun gear. For a two-head flat finishing machine, comprising: a rotatable inner peripheral gear; and a plurality of work holders provided between the sun gear and the inner peripheral gear and having an outer gear meshing with the sun gear and the inner peripheral gear. In the coolant supply device, a non-rotating coolant pipe is provided through the lower platen and the axis of the sun gear, a pump for supplying coolant is connected to the coolant pipe, and at an upper end of the coolant pipe,
An outlet for allowing coolant to flow out is provided on the upper surface of the sun gear, and a cup-shaped pocket for receiving coolant from the outlet is formed on the upper surface of the lower platen and coaxially with the lower platen. And supplying a coolant received in the pocket to the work by centrifugal force generated by rotation of the lower platen, while supplying coolant to the work from the outlet through the outlet. Coolant supply device. 2. A coolant guard that covers the upper grindstone, the lower grindstone, and the lower surface plate, and receives coolant from the outer periphery of the work holder and the pocket, and a drain hole disposed in a circumferential direction of the lower surface plate. And a lid provided on the bottom surface of the pocket, communicating with the drain hole, having a smaller diameter than the drain hole, and restricting a flow rate of coolant from inside the pocket to the coolant guard. 2. The coolant supply device for a two-head flat finishing machine according to claim 1, further comprising a coolant recovery unit comprising: