Working machinery

Abstract

To provide a machine tool having a drain structure that prevents the ingress of minute foreign matter. [Solution] A machine tool comprising a plurality of processing devices for processing a workpiece, having a drain structure in which oil supplied to a hydraulic drive means constituting a predetermined processing device is recovered through a drain pipe, wherein the drain structure is connected to an oil receiving member for recovering oil leaked in connection with the supply of hydraulic pressure to the hydraulic drive means, via an atmospheric opening member having an atmospheric hole formed in the pipe that opens to the atmosphere, and a filter member is attached to the atmospheric hole of the atmospheric opening member.

Description

Technical Field

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[0001] The present invention relates to a machine tool having a drain structure for recovering a part of oil supplied to a hydraulic driving means such as a hydraulic cylinder through a drain pipe.

Background Art

[0002] In order to handle the oil used by a machine tool through an appropriate flow path, for example, Patent Document 1 below discloses a machine tool provided with a circuit for sending oil to a predetermined location. Specifically, a circuit for sending the separated water-insoluble processing oil and water-soluble processing oil to the downstream side is configured in a secondary separation tank that stores the once-separated mixed processing oil. One is a first supply pipeline provided between the secondary separation tank and the workpiece, and the water-insoluble processing oil separated in the secondary separation tank by a second pump device is branched into a plurality of nozzle pipes and supplied to the workpiece. On the other hand, a drain pipeline for sending the water-soluble processing oil provided between the secondary separation tank and the primary separation tank is configured.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional machine tool described above, an adjustment hole is formed on the upper side of the drain pipe. This adjustment hole allows the inside of the drain pipe to communicate with the outside air (atmosphere), maintaining a constant liquid level in the secondary separation tank and preventing overflow, thus eliminating the need to install a pump. However, because the adjustment hole formed in the drain pipe faces upward, minute foreign matter can enter the pipe and subsequently mix with the oil used. However, in the conventional example, since the oil is sprayed onto the workpiece, even if foreign matter small enough to enter through the adjustment hole mixes with the oil, it does not have a significant impact. On the other hand, in oils that operate hydraulic drive means such as actuators, even minute foreign matter can cause malfunctions in the equipment.

[0005] Therefore, the present invention aims to provide a machine tool having a drain structure that prevents the ingress of minute foreign matter in order to solve the above problems. [Means for solving the problem]

[0006] The machine tool according to the present invention is composed of a plurality of processing devices that perform processing on a workpiece, and has a drain structure in which oil supplied to a hydraulic drive means constituting a predetermined processing device is recovered through a drain pipe, wherein the drain structure is connected to an oil receiving member for recovering oil leaked in connection with the supply of hydraulic pressure to the hydraulic drive means, via an atmospheric opening member having an atmospheric hole formed in the pipe that opens to the atmosphere, and a filter member is attached to the atmospheric hole of the atmospheric opening member. [Effects of the Invention]

[0007] According to the above configuration, when machining is performed on a workpiece by a machining device, oil is supplied to the hydraulic drive means that constitute the predetermined machining device. However, if the oil is supplied through, for example, a rotary lubrication joint, some of the oil will leak out, so the oil is recovered through a drain pipe. In such a drain structure, an atmospheric venting member with an atmospheric hole is formed to open the inside of the pipe on the upstream side near the oil receiving member to the atmosphere, improving the flow of oil in the drain pipe, and a filter member provided for the atmospheric hole prevents foreign matter from entering the drain pipe. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the internal structure of one embodiment of a machine tool. [Figure 2] This is a perspective view showing the drain structure installed in the workpiece spindle mechanism of a machine tool. [Figure 3] This is a perspective view showing the configuration of the atmospheric opening section in the drain structure. [Figure 4] This is a perspective view showing the configuration of the atmospheric opening section with a filter component attached in the drain structure. [Modes for carrying out the invention]

[0009] An embodiment of the machine tool according to the present invention will be described below with reference to the drawings. Figure 1 is a perspective view showing the internal structure of the machine tool according to this embodiment. The machine tool 1 of this embodiment is a two-axis opposing NC lathe on which various machining devices for machining a workpiece are assembled on a forward-tilting slant-type bed 6. The machining devices constituting the machine tool 1 are a first workpiece spindle device 3 that rotatably grips a workpiece, a second workpiece spindle device 4 that is positioned opposite the first workpiece spindle device 3 and rotatably grips a workpiece, and a turret device 5 having a plurality of turret tools T.

[0010] The first and second workpiece spindle units 3 and 4 are configured such that the spindles are in the machine width direction and horizontal, and that their spindles overlap coaxially. The first and second workpiece spindle units 3 and 4 have the same structure, with a spindle rotatably mounted within a casing 11, and a spindle chuck 12 integrated with the spindle rotated by a spindle motor to impart rotation to the gripped workpiece. In addition, in the first workpiece spindle unit 3, the casing 11 is fixed to the bed 6 as an integral part of the headstock 13, while in the second workpiece spindle unit 4, the casing 11 is mounted on a slidable headstock 14 and is configured to move in a direction parallel to the spindle according to a guide rail 15.

[0011] The turret device 5 is positioned above and behind the second work spindle device 4. The turret device 5 is configured such that multiple turret tools T are mounted at equal intervals in the circumferential direction on a disc-shaped turret tool post 16, and the rotation of the turret tool post 16 is used to index the turret tools T used for machining. The turret device 5 is also configured such that the turret tool post 16 can be moved in a predetermined direction by guide rails 17, etc. The machine tool 1 can move and position the cutting edges of the turret tools T to the machining position relative to the workpieces held by the first work spindle device 3 and the second work spindle device 4, respectively.

[0012] In the machining of a workpiece in machine tool 1, after machining is performed on the workpiece in the first workpiece spindle unit 3, the machine tool 1 can receive the machined workpiece by moving the second workpiece spindle unit 4. Through this movement of the workpiece within the machine tool 1, the first machining of the surface and the second machining of both reversed surfaces are performed consecutively on a single workpiece.

[0013] Incidentally, the first and second workpiece spindle devices 3 and 4 have a spindle rotatably mounted within a cylindrical casing 11, and a spindle chuck 12 is fixed to the tip of the spindle. The spindle is configured to be driven by a drive motor, and by controlling this drive motor, rotation is imparted to the spindle chuck 12 that grips the workpiece. The spindle chuck 12 requires opening and closing of the chuck jaws to grip and release the workpiece, and a hydraulic cylinder 21 is used as the hydraulic drive means to perform this opening and closing operation.

[0014] The first and second workpiece spindle devices 3 and 4 have a cylindrical spindle through which a rod-shaped drawbar is positioned at the center of rotation. The drawbar is connected to the piston rod of a hydraulic cylinder 21, which is located on the opposite side of the spindle chuck 12. The drawbar is displaced in the direction of the rotation axis by the extension and retraction of the hydraulic cylinder 21, and the spindle chuck 12 is configured with a drive transmission mechanism that converts this linear displacement into opening and closing movements of the chuck jaws.

[0015] The hydraulic cylinder 15 is configured to rotate in conjunction with the spindle in order to continuously apply a gripping force to the spindle chuck 12, which rotates during machining, to firmly hold the workpiece. Therefore, in order to maintain the piston rod in an extended or retracted state so that a gripping force can be obtained, it is necessary to continuously apply hydraulic pressure to the hydraulic cylinder 21. For this reason, a rotary lubrication coupling 22 (see Figure 2) is used for the hydraulic cylinder 21, and is configured so that the supply of hydraulic fluid (oil) to the cylinder tube is maintained even when the hydraulic cylinder 21 is rotating.

[0016] However, hydraulic equipment such as the rotary lubrication coupling 22 used in the machine tool 1 makes it difficult to completely seal the oil passage, and oil leaks through even the smallest gaps. Therefore, the first and second work spindle units 3 and 4 are provided with a drain structure to recover the oil leaked from the rotary lubrication coupling 22. Here, Figure 2 is a perspective view showing the drain structure provided in the first work spindle unit 3 of the machine tool 1 shown in Figure 1. Although not shown in detail, the hydraulic cylinder 21 of the second work spindle unit 4 is also provided with a similar drain structure to recover leaked oil.

[0017] The hydraulic cylinder 21 is fitted with a rotary lubrication coupling 22, to which an oil pipe (not shown) is connected, and is configured to supply and discharge oil used as hydraulic fluid. As mentioned above, oil leaks from the rotary lubrication coupling 22, so a box-shaped oil receiver 221 is integrally formed to receive the leaked oil. In this embodiment, the drain structure has a drain pipe 23 connected to a drain port formed on the bottom surface of the oil receiver 221. The drain pipe 23 is routed so that the leaked oil flows to an oil tank for oil recovery, but in particular, the drain structure on the first work spindle device 3 side shown in the figure has a long drain pipe 23.

[0018] The machine tool 1 has first and second workpiece spindle devices 3 and 4 respectively arranged on the left and right sides of the bed 6. In the space 61 formed at the center of the bottom surface of the bed 6, a chip conveyor for discharging chips and the like generated during machining to the outside of the machine is incorporated. Therefore, the oil tank is arranged on either the left or right side of the machine body. Among the first and second workpiece spindle devices 3 and 4 located on both the left and right sides, the drain pipe 23 of the drain structure at a distant position needs to be extended to the opposite side. In particular, since the chip conveyor is configured to protrude rearward of the machine body, the drain pipe 23 cannot pass around the rear side of the bed 6 and passes through the front side. Due to this, the drain pipe 23 has become long. On the other hand, for the second workpiece spindle device 4 (not shown), since the hydraulic cylinder 21 is arranged near the oil tank, the drain pipe of its drain structure can be shortened.

[0019] The drain pipe 23 has a first portion 231 that extends forward from the left side of the machine body as viewed from the front, which is continuous with a second portion 232 that extends longer than the width dimension along the front side of the bed 6, and further bends and is continuous with a third portion 233 that extends rearward along the right side of the machine body, and is connected to the oil tank behind the machine body. The drain pipe 23 is piped across the front of the bed 6 and has a length exceeding the width dimension of the machine body. Moreover, since the first workpiece spindle device 3 is installed on the front side of the slant-type bed 6, the rotary oil supply joint 22 is not at a high position. Therefore, the oil flows from the rotary oil supply joint 22 to an oil tank (not shown) with a small inclination over the entire length of the drain pipe 23.

[0020] Therefore, the oil sent into the drain pipe 23 is difficult to flow. Especially, since the rotary oil supply joint 22 has a sealed structure, it is pushed by the atmospheric pressure on the outlet side and the flow deteriorates further. Thus, in the drain structure, an atmospheric release portion is configured between the drain pipe 23 and the port of the oil receiver 221. That is, the upstream side of the drain pipe 23 near the oil receiver 221 is configured to be open to the atmosphere.

[0021] FIG. 3 is a perspective view showing the configuration of the atmosphere release portion in the drain structure, and particularly shows it from the diagonally upper side of the rotary oil supply joint 22. A T-shaped joint 25 is connected between the drain port of the oil receiver 221, and an atmosphere release member 26 that opens the inside of the drain pipe 23 to the atmosphere is connected to the joint portion protruding in the horizontal direction. The atmosphere release member 26 is an L-shaped hollow member, and an air hole 28 is formed at the tip portion attached upward. Therefore, the inside of the drain pipe 23 is opened to the atmosphere, and the oil flowing into it is pushed by the atmospheric pressure and sent to the downstream side and recovered in the oil tank.

[0022] By the way, while the atmosphere release member 26 improves the flow of oil in the thin drain pipe 23, since the air hole 28 opens upward, fine foreign matters can enter. The air hole 28 is a fine hole of about 2 mm to 3 mm, but if the fine foreign matters that have entered from there mix into the oil and flow into the oil tank, it may cause clogging or the like in the rotary oil supply joint 22 that is sent again. Therefore, in order to prevent the intrusion of foreign matters without impairing the effect of the air hole 28, a filter member 31 shown in FIG. 4 is attached to the atmosphere release member 26 with respect to the air hole 28. FIG. 4 is a perspective view showing the configuration of the atmosphere release portion in the drain structure as in FIG. 3, and particularly shows it at a horizontal angle where the attachment state of the filter member 31 is easy to understand.

[0023] The filter member used here blocks foreign matters while allowing air to pass through by closing the air hole 28. In the present embodiment, as a preferable one among such filter members, a commercially available silencer is attached as the filter member 31. For example, the silencer has exhaust holes formed in a cylindrical member as a core, and a cylindrical fine-mesh filter sheet is layered around it. And the upper end portion is closed, and a screw portion having a through hole formed at the center so as to communicate with the inside of the cylindrical member is formed at the lower end portion. Therefore, the atmosphere release member 26 has an improvement in the attachment portion for using such a silencer as the filter member 31.

[0024] The atmospheric release member 26 shown in Figure 3 has an atmospheric release nut member 27 fixed to its tip, which has an atmospheric hole 28 formed therein. However, this does not allow commercially available silencers to be used as filter members 31, so a coupling nut member 33 is used at the tip of the atmospheric release member 26. The coupling nut member 33 has a female threaded portion of a predetermined depth in its center, and a through-hole for atmospheric pressure is drilled in the center of the bottom surface of the female threaded portion. Although not shown, this atmospheric hole can have a larger diameter because it does not need to be designed to withstand the intrusion of foreign matter, unlike the atmospheric hole 28 shown in Figure 2. The atmospheric release member 26 can be easily attached by screwing the filter member 31 onto the coupling nut member 33 at its tip using the threaded portion, thereby sealing the atmospheric hole with a cylindrical filter.

[0025] Therefore, although the drain pipe 23 of the machine tool 1 in this embodiment is long due to its structure, the drain structure is equipped with an atmospheric release member 26 with an atmospheric hole, so that the oil can flow to the oil tank and be collected without stopping along the way. Furthermore, by attaching a filter member 31 to the atmospheric release member 26, the inside of the drain pipe 23 is kept open to the atmosphere while preventing the intrusion of foreign matter from the outside, thereby preventing interference with hydraulic-related equipment such as the rotary lubrication joint 22. In particular, in this embodiment, a commercially available silencer is used as the filter member 31, so it is inexpensive and easy to obtain. Moreover, since the filter member 31 using a silencer has a three-dimensional shape such as a cylinder and has a large surface area, it is possible to avoid the effects of clogging even when used for a long time.

[0026] Although one embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications are possible without departing from its spirit. For example, in the above embodiment, a silencer was used as an example of the filter member 31, but the invention is not limited to this and can be applied to filters in general. Furthermore, in the above embodiment, the drain structure for handling oil was described for the rotary lubrication coupling 22 to the hydraulic cylinder 21 of the first and second work spindle devices 3 and 4, but it may also be applied to the handling of drains in other hydraulic-related equipment. Furthermore, the machine tool is not limited to the lathe configuration shown in Figure 1; it may also be a machining center or other type of machine tool. [Explanation of Symbols]

[0027] 1...Machine tool 3...First workpiece spindle unit 4...Second workpiece spindle unit 5...Turret unit 12...Spindle chuck 21...Hydraulic cylinder 22...Rotating lubrication coupling 23...Drain pipe 26...Atmospheric release member 28...Atmospheric hole 31...Filter member 221...Oil receiver

Claims

1. A machine tool comprising multiple machining devices for machining a workpiece, and having a drain structure in which oil supplied to a hydraulic drive means constituting a predetermined machining device is recovered through a drain pipe, The drain structure is a machine tool in which the drain pipe is connected to an oil receiving member for recovering oil leaked in connection with the supply of hydraulic pressure to the hydraulic drive means, via an atmospheric opening member having an atmospheric hole formed in the pipe that opens to the atmosphere, and a filter member is attached to the atmospheric hole of the atmospheric opening member.

2. The machine tool according to claim 1, wherein the atmospheric release member is an L-shaped hollow member connected laterally to a T-joint connecting the drain port of the oil receiving member and the drain pipe, and a filter member is attached to the tip of which the atmospheric hole opens upward.

3. The machine tool according to claim 1, wherein the filter member is a commercially available three-dimensional silencer.

4. The drain structure is a machine tool according to any one of claims 1 to 3, wherein the drain pipe is piped to a length exceeding the width dimension of the machine body.

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