JPH048166B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a machining fluid supply device for an electric discharge machine,
In particular, this electrical discharge machine is designed to enable continuous supply of machining fluid easily and inexpensively, and is applied to an electrical discharge machine that 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 device for a machining machine.

[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 circuit device is The hollow electrode is made removable and rotation is applied to the workpiece, as well as vertical and horizontal feed to promote electrical discharge machining. 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 coexistence of electric circuits such as electric pump control circuits and piping circuits, which may cause failures and failures of the electric pump itself. In addition, there are inherent problems such as the need for periodic maintenance, and furthermore, the machining fluid supply means is relatively expensive, resulting in an increase in 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 system 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 is a new method that does not use the electric pump that was previously required. This is a machining fluid supply device for an electrical discharge machine. That is, according to the present invention, a rotating spindle is rotatably held at the lower end of the spindle head of an electrical discharge machine via an outer casing and has an electrode gripping device at the lower end, and a rotating spindle is provided at the center of the rotating shaft. A machining fluid pipe passage formed through the outer housing, an oil seal provided between the inner surface of the outer casing and the rotating main shaft, and a machining fluid supply passage in the outer casing and a machining fluid pipe passage of the rotating main shaft. A pair of sealed pipe joints that are connected to a machining fluid supply tank and alternately receive and send machining fluid by means of pressurized air from a pressure supply source, and are connected oppositely to the piston rod. a machining fluid supply cylinder, a pressure air switching valve that alternately supplies pressurized air to each of the machining fluid supply cylinders to a pressure air path between the pair of machining fluid supply cylinders, and a predetermined position of the piston rod. a dog that engages with a switching rod of the pressure air switching valve to switch the pressure air switching valve so that the piston changes direction at both moving ends of the piston rod; and a machining fluid supply path having a check valve that is piped from the machining fluid supply cylinder to the machining fluid supply path in the outer casing so that machining fluid is supplied to the machining fluid conduit. A machining fluid supply device for an electrical discharge machine is provided.

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 device for an electric discharge machine according to the present invention and an electrode rotation device for gripping and rotating an electrode.

In the following, prior to explaining the machining fluid supply device 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 rotating device 20 is attached to the lower end of the spindle head 10 of the electrical discharge machine by bolt connection or the like, and an electrode gripping device such as a collet type is provided at the lower end of the electrode rotating device 20. device 22
An electrode El in the form of a hollow rod or the like is removably attached to the holder. 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 a mounting flange 24 and a cylindrical housing 2 fixed and integrated with the mounting flange 24.
The main shaft 32 is rotatably supported by rotary bearings 30, 30, which are mounted and held in the hollow hole 26a of the housing 26. The main shaft 32 has a liquid conduit 34 at its inner center, and the electrode gripping device 22 described above is attached to the lower end of the main shaft 32 by screwing or the like via a suitable holding plate 36 or the like. At this time, the liquid pipe line 34 of the main shaft 32 and the electrode gripping device 2
Needless to say, the electrode gripping device 22 is positioned in advance so as to be aligned in the axial direction with the center hole of the electrode El attached to the electrode El. Electrode rotation device 20
Furthermore, 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 this motor 38, and a driven main shaft attached at an appropriate position along the axial direction of the main shaft 32. a pulley 42, and both drive and main shaft pulleys 40,
It is equipped with a transmission mechanism consisting of a transmission belt 44 stretched between 42, and rotation of the main shaft 32 imparts rotation to the hollow bar-shaped electrode El. The transmission mechanism can also be formed by a gear mechanism consisting of a gear train of pinions and gear wheels instead of the belt/pulley mechanism described above.

The electrode rotating device 20 further receives machining fluid supplied from the outside from a machining fluid supply path 46 formed in the mounting flange 24 of the outer casing 28, and connects the machining fluid pipe to the machining fluid conduit 34 of the main shaft 32. A joint portion 50 is provided. The pipe joint portion 50 includes a machining fluid reservoir chamber 48 in which the inner end of a machining fluid supply path 46 formed in the mounting flange 24 is open, and a machining fluid reservoir chamber 48 formed in the mounting flange 24 .
A first oil seal 52 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 liquid pipe of the main shaft 32. The passage 34 opens into the machining liquid reservoir 48 at the upper end of the main shaft 32. Here, the first pipe forming the pipe joint part 50 is
A second oil seal 54 is disposed below the oil seal 52, that is, on the outside or in the back area of the liquid sealing portion of the first oil seal 52, with an appropriate gap in the axial direction of the main shaft 32. Similarly, it is inserted and installed between the inner wall of the mounting flange 24 and the outer periphery of the main shaft 32, and is formed between the second oil seal 54 and the first oil seal 52. An annular gap is secured around the main shaft 32 as a pressurizing chamber 56 using pressurized air. That is, a pressurized air passage 58 formed by penetrating and drilling both the mounting flange 24 of the outer casing 28 and the housing 26 communicates with this pressurizing chamber 56, and air is supplied from the outside through this pressurized 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 is extracted from the machining fluid supplied from the outside to the machining fluid reservoir chamber 48 via the machining fluid supply path 46. First oil seal 52
Applying air pressure against the hydraulic pressure applied to the first oil seal 52, and therefore, when the hydraulic pressure and air pressure are balanced, no leakage will occur from the liquid sealing part of the first oil seal 52. Not only is this occurrence sufficiently prevented, but also 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.

When the above-mentioned backup action is performed on the pipe joint part 50 by air pressure, it is necessary to apply air pressure approximately equivalent to the hydraulic pressure of the machining fluid to obtain pressure equilibrium between the oil seals, especially the first oil seal 52. Needless to say, it is desirable to prolong the durability of the machining fluid, 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, it is sufficient to maintain the pressure equilibrium as described above in the pressure relationship between the two. However, according to the machining fluid supply device of the present invention described below, firstly, the above-mentioned pressurized air is continuously supplied at the same time as the machining fluid is continuously supplied. This makes it possible to balance the back pressure caused by the hydraulic pressure with the hydraulic 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. The machining fluid supply cylinders 62a, 62b have machining fluid chambers 64a, 64b and a pressure air chamber 66, respectively.
a, 66b, and each machining fluid supply cylinder 62
The machining liquid chambers 64a, 64b and pressure air chambers 66a, 66b of pistons 68a and 62b are
8b, and both pistons 68a and 68b have opposing structures in which their respective piston rods 70a and 70b are connected and integrated by a connecting flange 72, so that they reciprocate as one. It is located. Here, each machining fluid chamber 64a and 64b of both machining fluid supply cylinders 62a and 62b
are connected to the machining fluid tank 60 via check valves 74a and 74b, respectively, and the check valves 74a and 74b are connected to the machining fluid supply cylinder 62 from the machining fluid tank 60 side.
The valve is arranged so that it can be opened when supplying machining fluid to the machining fluid chambers 64a and 64b of a and 62b, and the machining fluid is blocked in the opposite direction. Further, each machining liquid chamber 64a, 64b is connected and coupled to a machining liquid supply path 46 formed in the mounting flange 24 of the electrode rotation position 20 described above through other check valves 76a, 76b, respectively.

On the other hand, the machining fluid supply cylinders 62a, 6 mentioned above
Each pressure air chamber 66a, 66b of 2b has 4 ports 2
It is connected to a pressure air supply source 88 via a pressure air switching valve 78 consisting of a position switching valve, and a pressure regulating valve 80 equipped with a filter 82, a relief valve 84, and a lubricator 86. After the pressure air supplied from the pressure air supply source 88 is adjusted and set to a desired pressure level by the pressure regulating valve 80, each pressure air chamber 66a, 66
This pressurized air causes the pistons 68 of both machining fluid supply cylinders 62a and 62b to
a and 68b are designed to be reciprocated. In other words, when both pistons 68a and 68b reciprocate, one machining fluid supply cylinder 62a or 62
A check valve 76a is connected from b to the electrode rotating device 20.
Or the machining fluid is supplied by opening 76b,
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, the machining fluid is supplied to both machining fluid supply cylinders 62.
Since the machining is performed alternately from a and 62b, the machining fluid is continuously supplied to the electrode rotating device 20. In addition, the dogs 90 provided at the positions of the connecting flanges 72 of both piston rods 70a, 70b engage alternately with the switching rods 92a, 92b of the pressure air switching valve 78 as the pistons reciprocate, thereby switching the pressure air. Since the valve 78 is equipped with a structure that automatically switches the valve 78, as long as the supply of pressurized air is continued,
The switching of the pressure air switching valve 78 is automatically repeated as described above.

In addition, a pressure regulating valve 8 is connected to a pressure air supply source 88.
A pipe line is provided for supplying regulated pressure air to the pressure air passage 58 of the electrode rotation device 20 described above through the tube 0, and this pressure air is supplied to the pipe of the electrode rotation device 20 as described above. The first part in the joint part 50
Back pressure is applied to the oil seal 52 from the pressurizing chamber 56. Here, both the pressure air supplied to the electrode rotating device 20 and the pressure air supplied alternately 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 that 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 storage chamber 48 of the pipe joint 50, the pressure of this machining fluid is approximately equal to the air pressure, and therefore the pressure of the machining fluid is approximately equal to the air pressure.
The pressure of the machining fluid acting on the first oil seal 52 and the pressurizing chamber 56 outside the first oil seal 52
The pressure acting on the liquid sealing portion of the first oil seal 52 can be balanced with the pressure acting on the liquid sealing portion of the first oil seal 52.

As described above, the machining fluid is once supplied from the machining fluid tank 60 to the machining fluid supply cylinders 62a and 62b,
Then, by pressurizing and supplying the fluid to the electrode rotating device under the action of pressurized air, not only can pressure equilibrium with the pressure air as described above be obtained, but compared to when machining fluid is supplied by a pump. It is possible to avoid the effects of pump vibration and also avoid the noise caused by pump operation.

Now, in FIG. 1, to explain the operation of the pair of machining fluid supply cylinders 62a and 62b in the machining fluid supply device, as shown in the figure, the pressure air switching valve 7
8 is switched, the pressure air from the pressure air supply source 88 is regulated by the pressure regulating valve 80, and then
It is supplied to the pressurized air chamber 66b in the right machining fluid supply cylinder 62b. Therefore, the air pressure of this pressurized air acts on the piston 68b, causing the piston rods 70a, 70b to move together to the left in the direction of the arrow.
Therefore, the machining fluid chamber 64b of the machining fluid supply cylinder 62b
The machining fluid received in the electrode rotating device 20 is continuously supplied to the machining fluid supply path 46 of the electrode rotating device 20 by opening the check valve 76b. The above piston rods 70a, 70b
In response to the left movement of the dog 90, the switching rod 92b
When the pressure air switching valve 78 is disengaged and then engaged with the switching rod 92a, the pressure air switching valve 78 is switched. Note that during leftward movement of the piston rods 70a and 70b, the pressure air chamber 66 in the left machining fluid supply cylinder 62a
Pressure air is pushed out from a, and the switching valve 78
During this time, as the volume of the machining fluid chamber 64a increases, a machining fluid receiving action occurs in the machining fluid chamber 64a, opening the check valve 74a and allowing machining fluid to be received from the machining fluid tank 60. This is done continuously.

When the pressure air switching valve 78 is switched,
The pressurized air is now supplied to the machining fluid supply cylinder 6 on the left side.
Since pressurized air is supplied to the pressurized air chamber 66a in 2a, the pistons 68a, 68b and the piston rods 70a, receive the air pressure of this pressurized air.
70b now moves 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, in the machining fluid supply cylinder 62b on the right side, the check valve 74b is opened from the machining fluid tank 60 into the machining fluid chamber 64b to receive the machining fluid. In this way, the pair of left and right machining fluid supply cylinders 62a and 62b arranged opposite each other alternately receive and supply machining fluid, and continuously supply 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 device, so that pump control is possible. 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 device is constructed of low-cost elements such as regulating valves, there is an effect that the cost of the machining fluid supply device can be reduced. Furthermore, the pressure on the oil seal forming the pipe joint is balanced by the processing fluid pressure and the air pressure regulated to the pressure that resists the processing fluid pressure, which reduces the burden on the oil seal. .

[Brief explanation of drawings]

FIG. 1 is a mechanical diagram including a sectional view showing the connection between the mechanism of the machining fluid supply device of the electrical discharge machine according to the present invention and the electrode rotation device. 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...Processing liquid tank, 62
a, 62b... machining fluid supply cylinder, 74a, 7
4b, 76a, 76b... Check valve, 78... Pressure air switching valve, 80... Pressure adjustment valve, 88... Pressure air supply source, 90... Dog, 92a, 92b...
Switching rod.

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 rotating spindle formed through the center of the rotating spindle. A machining fluid pipe line formed by providing an oil seal between the inner surface of the outer casing and the rotary main shaft, and a machining fluid supply passage in the outer casing and the machining fluid pipe line of the rotating main shaft are connected to each other. It has a sealed pipe joint for communication, and a pair of pistons that are connected to a machining fluid supply tank and alternately receive and send out machining fluid using pressurized air from a pressure supply source, with their respective piston rods facing each other. a pair of connected machining fluid supply cylinders; a pressure air switching valve that alternately supplies pressurized air to each of the machining fluid supply cylinders in a pressure air path between the pair of machining fluid supply cylinders; a dog provided at a predetermined position and engaged with a switching rod of the pressure air switching valve to switch the pressure air switching valve so that the piston changes direction at both moving ends of the piston rod; and a dog from the machining fluid supply cylinder. and a machining fluid supply path having a check valve piped from the machining fluid supply cylinder to the machining fluid supply path in the outer casing so that machining fluid is continuously supplied to the machining fluid conduit. A machining fluid supply device for an electric discharge machine, characterized in that: 2. Machining in an electric discharge machine according to claim 1, wherein pressurized air is supplied from the pressurized air supply source to the sealed pipe joint portion for applying back pressure against the hydraulic pressure of the machining fluid. Liquid supply device.