JPS62157721A - Machining liquid feeding device of electric discharge machine - Google Patents

Abstract

PURPOSE:To obtain an inexpensive nonfailure device by connecting two machining liquid feeding cylinders face to face, continuously feeding the pressure air to continuously operate the cylinders, and continuously feeding a machining liquid to the electric discharge machining section through the hole of a hollow electrode. CONSTITUTION:To feed a machining liquid, the pressure air of a pressure air feeding source 88 is fed into a pressure air chamber 66b, piston rods 70a, 70b are operated, and the machining liquid of a machining liquid chamber 64b is fed to a machining liquid feeding path 46. In this case, a dog 90 is removed from a switching bar 92b and coupled with a switching bar 92a to switch a pressure air selector valve 78. Then, pressure air enters a pressure air chamber 66a, and the piston rods 70a, 70b are moved to the right. Accordingly, the machining liquid is pushed out from a machining liquid chamber 64a and flows to the machining liquid feeding path 46. During this time, the machining liquid is fed into the machining liquid chamber 64b from a machining liquid tank 60. This device has the structure which avoids a bother encountered in case of a motor pump.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a machining fluid supply path for an electrical discharge machine, and in particular, the present invention relates to a machining fluid supply path for an electrical discharge machine, and in particular, it supplies machining fluid for electrical discharge machining from the center hole of a hollow electrode to the electrical discharge machining part between the workpiece and the workpiece. The present invention relates to a machining fluid supply path for an electrical discharge machine that is configured to be applied to a supply type electrical discharge machine so that machining fluid can be continuously supplied easily and inexpensively.

[Prior art]

When performing electrical discharge machining using a hollow electrode such as a rod in an electrical discharge machine, an electrode rotating device is attached to the lower end of the main spindle head of the electrical discharge machine, and an electrode gripping device provided at the lower end of the rotating main shaft of this electrode rotating device is The hollow electrode is made detachable and the electrical discharge machining progresses while applying rotation and vertical and horizontal feed to the workpiece.

In this case, machining fluid for cooling and removing machining debris is supplied to the electrical discharge machining section from the outside through the electrode rotation device and the center hole of the hollow electrode. Conventionally, as an external supply means for this machining fluid, a configuration has been adopted in which an electric pump for machining fluid supply is used to continuously supply machining fluid under pressure during electrical discharge machining, and the machining fluid supplied to the electrical discharge machining section is A structure was adopted in which the waste was collected through filtration means, etc., and recycled.

[Problems to be solved]

However, using conventional external supply means for machining fluid requires a mixed arrangement of electric circuits such as electric pump control circuits and piping circuits, which can lead to failures and failures of the electric pump itself. In addition, there are problems such as the need for periodic maintenance, and the relatively expensive machining fluid supply means, which increases the cost of the electrical discharge machine. Therefore, it is an object of the present invention to solve these problems.

[Means of solution and action]

In view of the above-mentioned object of the invention, the present invention constitutes a machining fluid supply cylinder in which two cylinder means are connected oppositely, and the machining fluid supply cylinder is continuously operated by continuous supply of pressurized air from a pressure air source. This is a new method that continuously supplies machining fluid to the electrical discharge machining section through the electrode rotation device and the center hole of the hollow electrode during electrical discharge machining, and does not use the electric pump that was previously required. This is a machining fluid supply path for an electrical discharge machine. That is, according to the present invention,
A rotating spindle rotatably held at the lower end of the spindle head of the electrical discharge machine via an outer casing and having an electrode gripping device at the lower end, and a machining liquid pipe formed through the center of the rotating spindle. , a sealed pipe joint portion that is formed by providing an oil seal between the inner surface of the outer casing and the rotating main shaft, and that connects the machining fluid supply path in the outer casing and the machining fluid pipe of the rotating main shaft with each other; a pair of opposingly connected machining fluid supply cylinders that are connected to a machining fluid supply tank and alternately receive and send out machining fluid using pressurized air from a pressurized air supply source; and a machining fluid supply path having a check valve piped to the machining fluid supply path in the housing, and the machining fluid in the machining fluid tank is transferred to the electrical discharge machining section through the machining fluid pipe of the rotating spindle. A machining fluid supply path for an electrical discharge machine is provided, which is configured to continuously supply machining fluid.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

〔Example〕

FIG. 1 is a sectional view showing a mechanism of a machining fluid supply path of an electrical discharge machine according to the present invention and an electrode rotating device for gripping and rotating an electrode.

In the following, prior to explaining the machining fluid supply path of the present invention, the electrode rotating device attached to the lower end of the spindle head of the electric discharge machine will be explained first.

Now, referring to FIG. 1, an electrode rotation device 20 is attached to the lower end of the spindle head 10 of the electric discharge machine by bolt connection or the like, and an electrode gripping device 22 such as a collet type is provided at the lower end of this electrode rotation device 20. An electrode E1 in the form of a hollow rod or the like is removably attached to the electrode E1. During the electrical discharge machining operation, this hollow rod-shaped electrode El descends to a lower workpiece (not shown) (fixed on a workpiece mounting table) as the spindle head 10 descends. Now, the electrode rotation device 20 includes an outer casing 28 consisting of a mounting flange 24 and a cylindrical housing 26 fixed and integrated with the mounting flange 24, and is mounted and held in the hollow hole 26a of the housing 26. A main shaft 32 is rotatably supported by rotary bearings 30, 30. And this main shaft 3
2 has a liquid conduit 34 in the inner center thereof, and the electrode gripping device 22 described above is attached to the lower end via a suitable holding plate 36 or the like by fixing with screws or the like. At this time, it goes without saying that the electrode gripping device 22 is positioned in advance so that the liquid conduit 34 of the main shaft 32 and the center hole of the electrode El attached to the electrode gripping device 22 are aligned in the axial direction. The electrode rotation device 20 further includes a motor 38 forming a rotational drive source for rotationally driving the main shaft 32 , a drive pulley 40 attached to the output shaft of the motor 38 , and a drive pulley 40 attached to the output shaft of the motor 38 .
a driven main shaft pulley 42 mounted at an appropriate position along the axial direction of
A transmission mechanism including a transmission belt 44 stretched between them is provided, and rotation of the main shaft 32 imparts rotation to the electrode FJ, such as a hollow rod. In addition, the transmission mechanism can also be formed by a gear mechanism consisting of a gear train of binions and gear wheels instead of the above-mentioned belt-pulley mechanism.

The electrode rotation device 20 further includes a machining fluid supply path 46 formed in the mounting flange 24 of the outer casing 28 for supplying machining fluid supplied from the outside.
In order to receive it from and supply it to the machining fluid pipe line 34 of the main spindle 32,
A pipe joint 50 for machining fluid is provided. This pipe joint part 5
0 is a machining fluid supply path 4 formed in the mounting flange 24.
A machining fluid reservoir chamber 48 with an open inner end of the machining fluid reservoir chamber 6 is provided between the inner wall of the mounting flange 24 and the outer periphery of the upper end portion of the main shaft 32 to prevent leakage of machining fluid from the machining fluid reservoir chamber 48. a first oil seal 52;
The liquid conduit 34 of the main shaft 32 opens into the machining liquid reservoir chamber 48 at the upper end of the main shaft 32 . Here, connect the above pipe joint part 5.
Below the first oil seal 52 that forms the
A second oil seal 54 is also attached to the mounting flange 24 at an appropriate gap in the axial direction of the main shaft 32 in the armor area.
The annular gap formed between the second oil seal 54 and the first oil seal 52 is disposed between the inner wall of the main shaft 32 and the outer periphery of the main shaft 32. A pressurized chamber 56 made of air is secured around the main shaft 32 . That is, a pressure air passage 58 formed by penetrating and drilling both the mounting flange 24 and the hanging 26 of the outer casing 28 communicates with this pressurization chamber 56, and air is supplied from the outside through this pressure air passage 58. It is configured such that the pressurized air can be supplied. When pressurized air is supplied to the outside of the liquid sealing portion of the first oil seal 52 in this way, this pressurized air flows into the machining fluid supply path 4 to the machining fluid reservoir chamber 48.
When the machining fluid supplied from the outside through 6 exerts air pressure on the first oil seal 52 against the hydraulic pressure applied to the first oil seal 52, and therefore, the hydraulic pressure and the air pressure are balanced. Not only is liquid leakage sufficiently prevented from occurring from the liquid sealing portion of the first oil seal 52, but fatigue deterioration due to pressure load on the first oil seal 52 is also prevented. As a result, it is possible to prevent the occurrence of problems in which machining fluid leaks and degrades the rotary bearing 30, etc., and also to sufficiently increase the service life of the first oil seal 52 forming the pipe joint portion 50.

In the backup action of the above-mentioned air pressure on the pipe joint portion 50, it is necessary to apply air pressure approximately equivalent to the hydraulic pressure of the machining fluid to obtain pressure balance between the oil seals, especially the first oil seal 52. Needless to say, it is desirable to extend the durability of the machining fluid over a long period of time, and it goes without saying that for this purpose, it is sufficient to supply the pressurizing chamber 56 with an air pressure commensurate with the hydraulic pressure of the machining fluid. Therefore, even if machining fluid and pressurized air are supplied independently, the pressure relationship between them will be
It is only necessary to maintain the pressure balance as described above, and therefore, it is sufficient to have a configuration in which the supply systems for machining fluid and pressurized air are provided with regulating means such as pressure regulating valves for appropriately regulating the fluid pressure and air pressure, respectively, but this will be explained below. According to the machining fluid supply path of the present invention, first of all, it is possible to continuously supply the machining fluid and at the same time balance the back pressure caused by the pressurized air with the fluid pressure.

That is, the machining fluid is stored in advance in a suitable machining fluid tank 60 and is supplied from this machining fluid tank 60 toward the electrode rotating device 20, but a pair of machining fluid supply cylinders 62a and 62b are provided in the supply path. will be placed.

Each of the machining fluid supply cylinders 62a, 62b has a machining fluid chamber 64a, 64b and a pressure air chamber 66a, 66b.
4a, 64b and the pressure air chambers 66a, 66b are separated by pistons 68a and 68b, and both pistons 68a and 68b are connected to each other by a connecting flange 72, respectively. By being integrated, they are arranged in a facing structure that reciprocates as one. Here, the reprocessing fluid supply cylinder 62a,
Each processing liquid chamber 64a and 64b of 62b has a check valve 74a, respectively.
, 74b to the machining fluid tank 60, and the check valves 74a, 74b connect the machining fluid chambers 54a, 64b of the machining fluid supply cylinders 62a, 62b from the machining fluid tank 60 side.
The valve is arranged so that it can be opened when machining fluid is supplied to the valve, and machining fluid is blocked in the opposite direction. Moreover, each processing liquid chamber 64a.

64b are connected and coupled to the machining fluid supply path 46 formed in the mounting flange 24 of the electrode rotating device 20 described above through other check valves 76a and 76b, respectively.

On the other hand, each pressure air chamber 66a, 66b of the machining fluid supply cylinders 52a, 62b described above is equipped with a pressure air switching valve 78 consisting of a four-bottom, two-position switching valve, a filter 82, a relief valve 84, and a luplicator 86 for pressure adjustment. It is connected to a pressure air supply source 88 via a valve 80, and according to the switching of the pressure air switching valve 78, the pressure air supplied from the pressure air supply aSS is adjusted and set to a desired pressure level by the pressure regulating valve 80. Then, the pressurized air is alternately supplied to each of the pressure air chambers 55a, 66b, and the pistons 58a, 68b of the reprocessing fluid supply cylinders 62a, 62b are reciprocated by this supply of pressurized air. In other words, both pistons 6
When 8a and 68b reciprocate, machining fluid is supplied from one machining fluid supply cylinder 62a or 62b toward the electrode rotating device 20 by opening the check valve 76a or 76b, and the other machining fluid supply cylinder 62b or 62a receives machining fluid from the machining fluid tank 60 via a check valve 74a or 74b. As long as the supply of pressurized air continues, machining fluid is supplied alternately from the re-machining fluid supply cylinders 62a and 62b, so machining fluid is continuously supplied to the electrode rotating device 20. be. In addition, both piston rods 70a, 70b
The dog 90 provided at the position of the connecting flange 72 engages alternately with the switching rods 92a and 92b of the pressure air switching valve 78 according to the reciprocating movement of the piston, thereby automatically switching the pressure air switching valve 78. As long as the supply of pressurized air continues, the switching of the pressurized air switching valve 78 is automatically repeated as described above.

Further, a pipe line is provided for supplying regulated pressure air from the pressure air supply source 88 to the pressure air passage 58 of the electrode rotating device 20 described above via the pressure regulating valve 80, and this pressure air is As described above, the pressurizing chamber 5
6 to exert back pressure. Here, both the pressurized air supplied to the electrode rotating device 20 and the one alternately supplied to the two machining fluid supply cylinders 62a and 62b are regulated to a desired constant pressure by the pressure regulating valve 80. In addition, in the machining fluid supply cylinders 62a and 62b, the machining fluid, which is pressurized by the action of the pressure air whose pressure is regulated at a constant level, is supplied to the machining fluid supply path of the electrode rotating device 20 via the check valve 76a or 76b. 46 to the machining fluid reservoir chamber 48 of the pipe joint 50, the pressure of this machining fluid is approximately equal to the air pressure, and therefore the machining fluid acting on the first oil seal 52 of the pipe joint 50 is Liquid pressure and the first
The pressure acting on the liquid seal portion of the first oil seal 52 from the pressure chamber 56 outside the oil seal 52 can be balanced.

As described above, the machining fluid is once supplied from the machining fluid tank 60 to the machining fluid supply cylinders 62a, 62b, and then is pressurized and supplied to the electrode rotation device under the action of pressurized air, thereby increasing the pressure as described above. Not only can pressure balance with air be obtained, but compared to the case where machining fluid is supplied by a pump, the influence of pump vibrations can be avoided, and noise caused by pump operation can also be avoided.

Now, in FIG. 1, the action of the pair of machining fluid supply cylinders 62a and 62b in the machining fluid supply path will be explained.
As shown in the figure, when the pressure air switching valve 78 is switched, the pressure air from the pressure air supply source 88 is regulated by the pressure regulating valve 80 and then supplied to the pressure air chamber 66b in the right machining fluid supply cylinder 62b. be done. Therefore, the air pressure of this pressurized air acts on the piston 68b, and the piston 11
70a.

70b is moved to the left in the direction of the arrow. Therefore, the machining fluid received in the machining fluid chamber 64b of the machining fluid supply cylinder 62b is continuously supplied to the machining fluid supply path 46 of the electrode rotating device 20 by opening the check valve 76b.

In response to the leftward movement of the piston rods 70a, 70b, the dog 90 is eventually separated from the switching frame 92b, and then the switching frame 92a
When engaged, the pressure air switching valve 78 is switched. Note that while the piston rods 70a and 70b are moving to the left, the left machining fluid supply cylinder 62a has a pressurized air chamber 66a.
Pressure air is pushed out from the air outlet of the switching valve 78 and discharged to the outside, and during this time, the machining liquid chamber 64a receives the machining liquid as the chamber volume increases, and the check valve 7
The machining fluid is continuously received from the machining fluid tank 60 by opening the valve 4a.

When the pressure air switching valve 78 is switched, pressure air is then supplied to the pressure air chamber 66a in the left machining fluid supply cylinder 62a, so that the piston 68a receives the air pressure of this pressure air. , 68b and the piston mechanisms 70a, 70b now move to the right in the opposite direction of the arrow. Therefore, the machining fluid is pushed out from the machining fluid chamber 64a in the left machining fluid supply cylinder 62a, and the machining fluid is supplied toward the electrode rotating device by opening the check valve 76a. During this time, the machining fluid supply cylinder 6 on the right side
2b, the check valve 74b is opened to receive the machining fluid from the machining fluid tank 60 into the machining fluid chamber 64b. In this way, the machining fluid supply cylinders 52a and 6 are arranged oppositely on the left and right sides.
2b alternately receives and supplies the machining fluid, and continuously supplies the machining fluid to the electrode rotating device 20.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the machining fluid can be supplied from a pair of cylinder devices without using an electric pump unlike the conventional machining fluid supply path, and therefore the pump control It is possible to supply machining fluid quietly without the need for complicated configurations such as circuits, and without problems such as vibration and noise caused by pumps. Since the machining fluid supply path is configured with low-cost elements such as regulating valves, it is possible to reduce the cost of the machining fluid supply path.

[Brief explanation of drawings]

FIG. 1 is a mechanical diagram including a sectional view showing a connection between a machining fluid supply path mechanism and an electrode rotating device of an electrical discharge machine according to the present invention. 10... Spindle head, 20... Electrode rotating device,
22... Electrode gripping device, 32... Main shaft, El...
- Electrode, 34... Liquid pipe line, 50... Pipe joint part, 52... First oil seal, 60...
Machining fluid tank, 62a, 62b... machining fluid supply cylinder, 74a,
74b, 76a, 76b ---Check valve, 7
8... Pressure air switching valve, 80... Pressure regulating valve, 88
... Pressure air supply source, 90 ... Dog, 92a, 92
b...Switching frame.

Claims (1)

[Scope of Claims] 1. A rotating spindle rotatably held at the lower end of the spindle head of an electrical discharge machine via an outer casing and having an electrode gripping device at the lower end, and a through-hole formed in the center of the rotating spindle. An oil seal is provided between the inner surface of the outer casing and the rotary main shaft, and the machining fluid supply path in the outer casing and the machining fluid pipe of the rotary main shaft are connected to each other. a pair of opposingly connected machining fluid supply cylinders that are connected to the machining fluid supply tank and alternately receive and send out machining fluid by means of pressurized air from a pressurized air supply source; and a machining fluid supply path having a check valve that is piped from a machining fluid supply cylinder to a machining fluid supply path in the outer casing, and the machining fluid in the machining fluid tank is transferred to the machining fluid pipe of the rotating main shaft. 1. A machining fluid supply device for an electrical discharge machine, characterized in that it is configured to continuously supply fluid to an electrical discharge machining section via a channel. 2. A pressure air switching valve capable of alternately supplying pressurized air to each of the machining fluid supply cylinders is provided in the pressure air path between the pressurized air supply source and the pair of machining fluid supply cylinders, and the machining fluid 2. The machining fluid supply device for an electrical discharge machine according to claim 1, wherein the operating portion of the supply cylinder is engaged with a switching rod of the pressure air switching valve. 3. Pressure air is supplied from the pressure supply source to the sealed tube continuation portion for applying back pressure against the hydraulic pressure of the processing fluid, as set forth in claim 1 or 2. Machining fluid supply device for electric discharge machine. 4. A patent claim in which a check valve is provided between the machining fluid tank and the pair of machining fluid supply cylinders to prevent the machining fluid from flowing from the cylinder side to the machining fluid tank side, thereby ensuring smooth reception of the machining fluid. A machining fluid supply device for an electrical discharge machine according to item 1.