Machine tools and splash guards

Abstract

When a maintenance opening in a splash guard is covered with multiple covers, the open / closed state of that opening can be detected with fewer sensors. [Solution] A machine tool in one embodiment includes a splash guard having a maintenance opening, a cover unit assembled to the splash guard to close the opening, and a sensor for detecting the open / closed state of the opening. The cover unit includes a first cover that shields a first opening region of the opening, a second cover that is detachably attached to the splash guard separately from the first cover to shield a second opening region of the opening, and a third cover that is detachably attached to the second cover to shield a third opening region of the opening formed between the first cover and the second cover. The sensor is provided between the first cover and the third cover.

Description

Technical Field

[0005]

[0001] The present invention relates to a machine tool, and particularly to an opening and closing structure of a maintenance opening provided in a splash guard.

Background Art

[0002] The housing of a machine tool is constituted by a cover called a splash guard. By providing the splash guard so as to surround the machining chamber, it is possible to prevent chips and cutting fluid from scattering around during the machining of a workpiece. A door for accessing the inside of the machining chamber is provided on the front surface of the housing, and a maintenance opening may also be provided on the side surface of the housing.

[0003] For example, in the case of a turning center, a connection opening is provided so that a bar feeder can be connected to the workpiece spindle inside the housing. The bar feeder is a device that automatically supplies a long workpiece (bar) from the rear of the workpiece spindle (see Patent Document 1). When connecting the bar feeder to the turning center, the opening of the splash guard located behind the workpiece spindle is opened, and the tip of the bar feeder is connected. On the other hand, when the bar feeder is not in use, the opening is closed with a cover so as not to rotate the workpiece spindle while exposing the workpiece to the outside of the housing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In such cases, multiple covers would need to be placed in close proximity to close these openings. The workpiece spindle must be driven with all of these openings closed. To achieve this, installing a sensor to detect the closed state of each cover would increase costs. On the other hand, a configuration where all of these openings are closed with a single cover is also conceivable, but the cover would be larger, making its removal a greater burden. This problem is not limited to turning centers; it can occur similarly in any machine tool that has multiple maintenance openings located close together on a splash guard. [Means for solving the problem]

[0007] One aspect of the present invention is a machine tool. This machine tool includes a splash guard having a maintenance opening, a cover unit assembled to the splash guard to close the opening, a sensor for detecting the open / closed state of the opening, and an interlock unit that performs an interlock to restrict the driving of the machining part when the open state of the opening is detected. The cover unit includes a first cover that is detachably attached to the splash guard to shield a first opening region of the opening, a second cover that is detachably attached to the splash guard separately from the first cover to shield a second opening region of the opening, and a third cover that is detachably attached to the second cover and, when the second cover is attached to the splash guard, shields a third opening region of the opening formed between the first cover and the second cover. The sensor is provided between the first cover and the third cover.

[0008] Another aspect of the present invention is a splash guard having an opening for maintenance of a machine tool. The splash guard comprises a cover unit assembled to close the opening and a sensor for detecting the open or closed state of the opening. The cover unit includes a first cover which is detachably attached to the splash guard to shield a first opening region of the opening; a second cover which is detachably attached to the splash guard separately from the first cover to shield a second opening region of the opening; and a third cover which is detachably attached to the second cover and which, when the second cover is attached to the splash guard, shields a third opening region of the opening formed between the first cover and the second cover. The sensor is provided between the first cover and the third cover. [Effects of the Invention]

[0009] According to the present invention, when a maintenance opening provided in a splash guard is closed with multiple covers, the open / closed state of the opening can be detected with fewer sensors. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the external appearance of the machine tool according to this embodiment. [Figure 2] This is a hardware configuration diagram of a machine tool. [Figure 3] This is a perspective view showing the internal structure of a machine tool. [Figure 4] This is a front view showing the internal structure of the containment chamber. [Figure 5] This diagram shows the configuration and arrangement of the cover unit. [Figure 6] This is a diagram showing the structure of the cover unit and its surroundings. [Figure 7] This is an enlarged view of section A in Figure 6(B). [Figure 8] This diagram schematically illustrates the detection method using sensors. [Figure 9] This diagram shows the configuration of the cover unit in a modified example. [Modes for carrying out the invention]

[0011] One embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a perspective view showing the external appearance of a machine tool according to this embodiment. For convenience, the vertical, horizontal, and left-right directions, as viewed from the front of machine tool 1, will be described below as the X, Y, and Z directions, respectively.

[0012] Machine tool 1 is a turning center that processes a workpiece into a desired shape by changing tools as needed. A processing chamber 4 is provided inside the housing 2 of machine tool 1. The processing chamber 4 is surrounded by splash guards that form the sides of the housing 2. A processing device for processing the workpiece is installed in the processing chamber 4. An operation panel 6 for operating the processing device is provided on the front of the housing 2.

[0013] A coolant tank 8 for storing coolant supplied to the machining chamber 4 is provided adjacent to the housing 2 of the machine tool 1. The coolant is used as a cutting fluid for heat removal and lubrication of the tool and workpiece during machining, but it is also used as a cleaning fluid to remove chips scattered in the machining chamber 4. Since the coolant becomes a mist in the machining chamber 4, if it is discharged outside the machine as is, it will cause contamination of the factory. For this reason, the machine tool 1 is provided with a mist collector 10 for recovering the misted coolant (also called "oil mist").

[0014] A door 7 for accessing the processing chamber 4 is provided on the front of the housing 2, and a maintenance opening 70 is provided on the left side of the housing 2. A cover unit 50 is provided to close the opening 70. The cover unit 50 is composed of multiple covers, which will be described later. The cover unit 50 is equipped with a sensor that detects when any of these covers are open. In this embodiment, the detection of this open state is achieved with fewer sensors than the number of covers that make up the cover unit 50. The details are described below.

[0015] Figure 2 is a hardware configuration diagram of the machine tool 1. The machine tool 1 includes an information processing device 100, a machining control device 102, and a machining device 104. The machining control device 102 functions as a numerical control unit and outputs a control signal to the machining device 104 according to a machining program (NC program). The machining device 104 drives a work spindle according to an instruction from the machining control device 102, moves a tool, and machines a work.

[0016] The machining device 104 includes a work spindle drive unit 110, a tool post drive unit 112, a coolant supply device 114, and a mist collector drive unit 116. In this embodiment, as will be described later, a first work spindle and a second work spindle are provided as work spindles capable of holding a work. The work spindle drive unit 110 includes a first spindle drive unit 120 that drives the first work spindle and a second spindle drive unit 122 that drives the second work spindle. The tool post drive unit 112 drives a turret-type tool post described later.

[0017] The coolant supply device 114 supplies coolant to the machining chamber 4. The coolant supply device 114 is configured by arranging, in addition to the coolant tank 8 described above, a coolant discharge portion, a pump, and a control valve, which are not shown, in a coolant circulation path. The coolant discharge portion includes a nozzle that discharges coolant and an actuator that drives the nozzle, and discharges coolant toward a set target position. The pump pumps up the coolant stored in the coolant tank 8 and supplies it to the coolant discharge portion. The control valve includes a plurality of on-off valves and appropriately switches the coolant flow path in the coolant circulation path.

[0018] The mist collector drive unit 116 drives the mist collector 10 when coolant is discharged in the machining chamber 4. The mist collector drive unit 116 includes a motor that drives the fan of the mist collector 10.

[0019] The information processing device 100 includes an operation panel 6 and outputs control commands to the processing control device 102 based on the operator's input. The information processing device 100 also controls the screen displayed on the monitor of the operation panel 6 in accordance with the operator's input.

[0020] Each component of the information processing device 100 is realized by hardware including arithmetic units such as a CPU (Central Processing Unit) and various coprocessors, memory and storage devices, and wired or wireless communication lines connecting them, as well as software stored in the storage devices that supplies processing instructions to the arithmetic units. The computer program may consist of device drivers, an operating system, various application programs located at a higher layer, and libraries that provide common functions to these programs.

[0021] The information processing device 100 includes a detection unit 106 and an interlock unit 108. The detection unit 106 acquires detection information from various sensors installed on the machine tool 1, such as the sensors described later that are provided on the cover unit 50. Based on the detection information from the sensors, the interlock unit 108 determines that any of the covers constituting the cover unit 50 is open (i.e., when the open state of the opening 70 is detected), and outputs an interlock command to the machining control device 102. When the machining control device 102 receives this interlock command, it restricts the driving of each part, including the workpiece spindle. In this embodiment, the driving of each part is prohibited by the interlock, but the restriction may be limited to an extent that ensures safety, such as reducing the driving speed of each part by interlocking. Automatic operation of the machining device 104 may be prohibited by the interlock, while manual operation may be permitted.

[0022] Figure 3 is a perspective view showing the internal structure of machine tool 1. For ease of explanation, the front and left and right side covers (splash guards) of the housing 2 are shown removed. The machine tool 1 has a partition wall 12 that divides the space above the bed 3 (base) inside the housing 2 into a processing chamber 4 and a storage chamber 5.

[0023] The machining apparatus 104 is configured by mounting a first headstock 14, a second headstock 16, and a tool post 18, etc., on the bed 3. The first headstock 14 is housed in a storage chamber 5, and the second headstock 16 and tool post 18 are housed in a machining chamber 4. Since no moving parts are provided in the storage chamber 5, it is sized to be sufficient for housing the first headstock 14 and is considerably smaller than the machining chamber 4. The first headstock 14 rotatably supports the first workpiece spindle 20. The tip of the first workpiece spindle 20 penetrates the partition wall 12 and is exposed to the machining chamber 4. A chuck capable of holding a workpiece is attached to the tip of the first workpiece spindle 20. The first workpiece spindle 20 is rotationally driven by the first spindle drive unit 120 described above.

[0024] The second headstock 16 rotatably supports the second work spindle 22. The second headstock 16 is covered with a dedicated cover 17 to prevent the ingress of chips and coolant. The second work spindle 22 is exposed from the cover 17. A chuck capable of holding a workpiece is attached to the tip of the second work spindle 22. The second work spindle 22 is rotationally driven by the second spindle drive unit 122 described above. The second work spindle 22 can be replaced with a tailstock (not shown) as needed.

[0025] The first work spindle 20 and the second work spindle 22 are arranged to face each other coaxially in the Z direction. The first headstock 14 and the second headstock 16 each have built-in spindle motors for rotating the work spindles. The second headstock 16 is movable in the Z direction by driving a moving mechanism (not shown). That is, the second headstock 16 can move the second work spindle 22 closer to or further away from the first work spindle 20, thereby adjusting the distance between the first work spindle 20 and the second work spindle 22. This moving mechanism is, for example, a screw feed mechanism using a ball screw.

[0026] The tool post 18 is located in the machining chamber 4, further back in the depth direction than the second spindle head 16, and functions as a "tool holder." The tool post 18 comprises a turret base 24 and a turret 26. The turret base 24 has a rotation axis extending in the Z direction and rotatably supports the turret 26. The turret base 24 is equipped with a spindle motor for rotationally driving the turret 26. The turret 26 is provided with a plurality of clamping / unclamping mechanisms (not shown) along its periphery. These clamping / unclamping mechanisms allow for the attachment and detachment of multiple different types of tools (not shown).

[0027] The turret base 24 is movable in the X, Y, and Z directions by driving a moving mechanism (not shown), allowing adjustment of the positional relationship between the workpiece held by each workpiece spindle and the tool held by the turret 26. This moving mechanism is, for example, a screw feed mechanism using a ball screw.

[0028] With this configuration, the turret 26 is movable in the X, Y, and Z directions. Furthermore, the turret 26 is rotatable around an axis extending in the Z direction, thereby allowing for the switching of the tool used for machining. In other words, the turret 26 moves relative to the workpiece supported by one or both of the first workpiece spindle 20 and the second workpiece spindle 22 in three orthogonal axial directions, enabling cutting or turning of the workpiece using the tool.

[0029] A coolant discharge unit is provided at a predetermined location in the machining chamber 4 (not shown). The coolant discharge unit discharges coolant toward the tool when machining the workpiece, and also discharges coolant to wash away chips scattered inside the machining chamber 4. Some or all of the tools supported by the turret 26 may also be equipped with the function of a so-called through-spindle coolant system. That is, an internal passage for circulating coolant may be provided in the tool, and this internal passage may be connected to a coolant circulation path. A discharge port is provided at the tip of the tool, forming one end of the internal passage and discharging coolant. By discharging coolant from the tip of the tool in this way during machining, it is possible to improve machining accuracy, shorten machining time, extend tool life, and improve chip evacuation performance.

[0030] The mist collector 10 is positioned in the space above the first headstock 14 in the containment chamber 5. The partition wall 12 is provided with a mist intake port 28 that opens toward the machining chamber 4. In the containment chamber 5, a pipe 30 is provided connecting the intake port 10a of the mist collector 10 to the mist intake port 28. A cover 32 is provided on the side of the partition wall 12 to cover the mist intake port 28 from above. The cover 32 opens toward the bottom to restrict the direct entry of coolant discharged from the coolant discharge port into the mist intake port 28. When the mist collector 10 is driven, oil mist in the machining chamber 4 is taken in by the mist intake port 28 and guided through the pipe 30 to the intake port 10a. The oil mist is collected inside the mist collector 10, and the purified air is discharged from the exhaust port 10b.

[0031] Figure 4 is a front view showing the internal structure of containment chamber 5. In the containment chamber 5, a support column 40 is erected on the bed 3 separately from the first spindle head 14. A table 42 is provided at the upper end of the support column 40, and the mist collector 10 is placed on the table 42. The first spindle head 14 is located on the front side in the depth direction of the containment chamber 5, and the support column 40 is located on the back side in the depth direction. Because the table 42 is provided so as to extend from the upper end of the support column 40 toward the front, the mist collector 10 is cantilevered by the support column 40 and is located in front of the support column 40 in the depth direction.

[0032] The mist collector 10 is positioned relatively further back than the first headstock 14. The outlet 10b of the mist collector 10 communicates with the outside of the machine through an opening 34 provided in the housing 2. The piping 30 extends from the intake port 10a of the mist collector 10, curves slightly towards the front, and connects to the mist intake port 28. The piping 30 is positioned above the first headstock 14. In this way, the mist collector 10 and the piping 30 are positioned to make effective use of the space above the first headstock 14 in the housing chamber 5.

[0033] The mist collector 10 is constructed by housing a fan and a filter (not shown) in a case 44. A motor for rotating the fan is installed in the case 44. A hood 46 (exhaust port cover) is detachably attached to the case 44 so as to surround the outlet 10b. The configuration of the mist collector 10 is publicly known, as described in, for example, Japanese Patent Publication No. 7144631, so a detailed explanation is omitted.

[0034] When the fan is driven by the operation of the mist collector 10, air containing oil mist from the processing chamber 4 is drawn in through the mist intake port 28 and guided through the piping 30 to the intake port 10a of the mist collector 10. This air is purified by passing through a filter to remove the oil mist, and then discharged outside the machine through the outlet port 10b.

[0035] The cover unit 50 is attached to the left side of the housing 2 (splash guard 2a) so as to be positioned opposite the first headstock 14 and the first work spindle 20 in the axial direction. The bar feeder 60 can be installed on the outside of the splash guard 2a so as to be opposite the cover unit 50. The bar feeder 60 is a device that automatically supplies long workpieces W (bar stock) from the rear of the first work spindle 20. When connecting the bar feeder 60 to the machine tool 1, the central cover (third cover 53, which will be described later in relation to Figure 5) that constitutes the cover unit 50 is removed to secure an insertion path for the workpieces W supplied from the bar feeder 60.

[0036] The bar feeder 60 includes a work stocker capable of accommodating multiple workpieces W, a work feeder for taking workpieces W from the work stocker and setting them in a standby position, and a workpiece pushing mechanism for pushing the workpieces W set in the standby position toward the first workpiece spindle 20. Note that the configuration and operation of the bar feeder 60 are publicly known, as described in, for example, Japanese Patent Publication No. 7108148, and therefore a detailed explanation is omitted.

[0037] A chuck cylinder 62 is provided on the first spindle head 14. The chuck cylinder 62 drives the chuck 20a, which is attached to the tip of the first workpiece spindle 20. In this embodiment, the chuck cylinder 62 is a hydraulic cylinder, but an air cylinder may also be used. The operation of the chuck cylinder 62 allows the chuck 20a to perform a gripping operation.

[0038] A sensor 64 for checking the operation of the chuck cylinder 62 is provided behind the first workpiece spindle 20 on the first headstock 14. The sensor 64 detects the tip of a rod (not shown) connected to the piston of the chuck cylinder 62. Based on the detection state by this sensor 64, it is possible to confirm whether or not the gripping operation of the chuck 20a is normal. Note that the configuration and operation of such a chuck cylinder 62, as well as the confirmation of the gripping operation by the sensor 64, are publicly known, as described in, for example, Japanese Patent Application Publication No. 2023-180634, so a detailed explanation is omitted.

[0039] Figure 5 shows the configuration and arrangement of the cover unit 50. For ease of explanation, the front cover (splash guard) of the housing 2 is shown removed. A maintenance opening 70 is provided in the lower half of the splash guard 2a that forms the side of the housing 2. The opening 70 has a width and height approximately equal to that of the first headstock 14 when viewed in the axial direction of the first work spindle 20, and is roughly rectangular in shape. The cover unit 50 has a complementary shape to the opening 70 and is attached to the splash guard 2a to close the opening 70.

[0040] The cover unit 50 is constructed by assembling a first cover 51, a second cover 52, and a third cover 53. The first cover 51 is detachably attached to the splash guard 2a to shield a first opening region 71 corresponding to the upper half of the opening 70. The second cover 52 is detachably attached to the splash guard 2a separately from the first cover 51 to shield a second opening region 72 corresponding to the lower half of the opening 70. The third cover 53 is detachably attached to the second cover 52 to shield a third opening region 73 corresponding to the central part of the opening 70. The third cover 53 is positioned axially opposite to the workpiece supported by the workpiece spindle 20. The first cover 51 and the second cover 52 are arranged to surround the third cover 53.

[0041] An opening 34 is provided in the upper half of the splash guard 2a, exposing the side of the mist collector 10. The opening 34 has approximately the same width and height as the mist collector 10, causing the hood 46 to protrude to the outside of the splash guard 2a. The main body of the mist collector 10 (i.e., the functional parts such as the fan and filter) is housed in the containment chamber 5, and only the hood 46 protrudes to the outside of the housing 2. The hood 46 regulates the direction of air discharged from the mist collector 10 within the factory. By making only the hood 46 protrude in this way, the protrusion from the housing 2 can be reduced.

[0042] By individually removing the three covers that make up the cover unit 50, maintenance can be performed on the equipment installed in the storage chamber 5 individually. Specifically, the third cover 53 is removed when connecting the bar feeder 60 described above. The third cover 53 is of a size that is necessary and sufficient for supplying the workpiece W. In other words, when connecting the bar feeder 60, it is sufficient to remove only the third cover 53. When the bar feeder 60 is not in use, the third cover 53 is reattached to close the opening 70.

[0043] By removing the first cover 51, the sensor 64 used to check the operation of the chuck cylinder 62 can be maintained. Furthermore, the mist collector 10, located directly above the first headstock 14, can also be maintained. Although not shown in the diagram, the mist collector 10 is fixed to the table 42 by several screws, which are mounted on the underside of the table 42. Therefore, by removing the first cover 51, these screws can be loosened. This allows the mist collector 10 to be detached from the table 42 and removed through the opening 34.

[0044] By removing the second cover 52, maintenance can be performed on the equipment located at the bottom of the first spindle head 14. However, since the third cover 53 is fixed to the second cover 52, removing the second cover 52 also removes the third cover 53. Because the cover unit 50 is divided into the first cover 51 and the second cover 52, the first cover 51 and the second cover 52 can be removed individually even when the bar feeder 60 is connected and the workpiece W is inserted. In this way, the workload is reduced because only the appropriate cover needs to be removed depending on the maintenance area.

[0045] On the other hand, since the cover unit 50 is located on the axis of the first workpiece spindle 20, it is unsafe if machining is started with any of the covers removed. For this reason, the cover unit 50 is equipped with a sensor 54 to detect whether any of the three covers have been removed. As described above, the interlock unit 108 outputs an interlock command when it determines, based on the detection information from the sensor 54, that any of the covers constituting the cover unit 50 are open.

[0046] Figure 6 shows the structure of the cover unit 50 and its surroundings. Figure 6(A) is a perspective view of the splash guard 2a seen from its outer side, and Figure 6(B) is a perspective view of the splash guard 2a seen from its inner side (containment chamber 5 side). Figure 7 is an enlarged view of part A in Figure 6(B).

[0047] As shown in Figure 6(A), the splash guard 2a is composed of an upper cover 2b and a lower cover 2c arranged vertically. An opening 34 is provided in the upper cover 2b, and an opening 70 is provided in the lower cover 2c. Each cover can be individually attached and detached to form the left side of the housing 2. In a modified example, the splash guard 2a may be configured as a single cover without being divided into upper and lower sections.

[0048] Covers 51-53 are detachably assembled to the lower cover 2c and open and close the opening 70. Covers 51-53 are obtained, for example, by press-forming a metal plate. The first cover 51 has a rectangular shape with a semicircular cutout in the center of the lower edge. The first cover 51 is fixed to the splash guard 2a (lower cover 2c) by attaching a plurality of screws 56 along its periphery and shields the first opening area 71 of the opening 70.

[0049] The second cover 52 has a rectangular shape with a semicircular cutout in the middle of the upper center. The second cover 52 is fixed to the splash guard 2a (lower cover 2c) by attaching a number of screws 57 along its periphery, and shields the second opening area 72 of the opening 70. When the first cover 51 and the second cover 52 are attached to the splash guard 2a, a circular third opening area 73 is formed in the center of the opening 70.

[0050] The third cover 53 is disc-shaped and is attached to shield its third opening region 73. The third cover 53 is fixed to the second cover 52 by a number of screws 58, but not to the first cover 51. Therefore, when the second cover 52, to which the third cover 53 is fixed, is attached to the splash guard 2a, the third opening region 73 formed between the first cover 51 and the second cover 52 can be shielded. Alternatively, the third cover 53 may be attached to the second cover 52 after the second cover 52 has been attached to the splash guard 2a. On the other hand, if the second cover 52 is removed from the splash guard 2a, the third cover 53 will also be removed. In other words, the third cover 53 can only shield the third opening region 73 when it is attached to the second cover 52. The third cover 53 can be removed independently while the second cover 52 remains attached to the splash guard 2a.

[0051] As shown in Figure 6(B), a sensor 54 is located on the rear side of the cover unit 50. The sensor 54 includes a sensor body 80 and a detection element 82. The detection element 82 is the object to be detected by the sensor body 80 and functions as the "detected part". The sensor body 80 functions as the "detection part" and detects the detection element 82 when it is nearby, outputting the detection signal to the information processing device 100. The sensor body 80 is connected to the information processing device 100 via a signal line 59 (signal cable). The interlock unit 108 acquires the detection information of the sensor 54 via the signal line 59.

[0052] In this embodiment, a non-contact proximity sensor (proximity switch) is used as the sensor 54. Any type of proximity sensor may be used, such as inductive, capacitive, or magnetic. In modified examples, a photoelectric sensor may be used. When a reflective photoelectric sensor is used, a reflector, which serves as the "detected part," is provided on the detection element 82. Alternatively, the reflector may be directly assembled to the third cover 53. A part of the third cover 53 may function as a reflector (reflective area). Furthermore, a contact-type sensor such as a limit switch may be used.

[0053] As shown in Figure 7, the sensor body 80 is fixed to a support member 84 provided on the back surface of the first cover 51. To prevent unauthorized use of the sensor 54, the sensor body 80 is fixed to the support member 84 and, consequently, to the first cover 51 by a unidirectional screw. When removing the first cover 51 from the splash guard 2a, it is necessary to disconnect the signal line 59 from the sensor body 80. On the other hand, the detection element 82 is fixed to a support member 86 provided on the back surface of the third cover 53. A concave slit 88 is provided on the inner periphery of the first cover 51, and the support member 86 is positioned on the housing chamber 5 side by passing through the slit 88. This allows the detection element 82 to be positioned facing the sensor body 80 in the radial direction of the third cover 53.

[0054] As the first cover 51 and the third cover 53 are assembled in this manner, the detection element 82 faces the sensor body 80, allowing the sensor 54 to detect the closed state of the opening 70. Since the third cover 53 is fixed to the second cover 52, all of the covers 51 to 53 are assembled at this time to form the cover unit 50, and the opening 70 is closed.

[0055] When the third cover 53 is removed, it is removed together with the detection element 82. On the other hand, when the first cover 51 is removed, the connection between the sensor body 80 and the signal line 59 must be disconnected, so the sensor 54 is turned off. In this way, since the signal line 59 is disconnected in order to remove the first cover 51, the length of the signal line 59 can be kept to the minimum necessary, and the wiring can be made neater.

[0056] Figure 8 schematically illustrates the detection method by the sensor 54. Figures 8(A) to 8(D) show the relationship between the open / closed state of the cover unit 50 and the detection state by the sensor 54. When the opening 70 of the splash guard 2a is completely closed by the cover unit 50 (Figure 8(A)), the sensor body 80 and the detection element 82 face each other. As a result, the sensor 54 turns on (the sensor body 80 detects the detection element 82). The interlock unit 108 releases the interlock when the detection unit 106 detects this state (sensor 54 is on) (see Figure 2).

[0057] On the other hand, when only the third cover 53 is removed (Figure 8(B)), the detection element 82, which is integrated with the third cover 53, is also removed, so the sensor 54 turns off (the sensor body 80 does not detect the detection element 82). Similarly, when only the first cover 51 is removed (Figure 8(C)), the sensor body 80 cannot face the detection element 82, so the sensor 54 turns off. When the second cover 52 is removed (Figure 8(D)), the third cover 53, which is fixed to the second cover 52, is also removed, so the sensor 54 turns off. The interlock unit 108 performs an interlock when the detection unit 106 detects this state (sensor 54 is off) (see Figure 2).

[0058] Furthermore, even if the splash guard 2a (especially the lower cover 2c) were to be removed, the connection between the cover unit 50 and the signal line 59 would be disconnected (see Figure 6). This would create an interlock, preventing the first workpiece spindle 20 from rotating.

[0059] The machine tool has been described above based on the embodiments. In this embodiment, a maintenance opening 70 is provided in the splash guard 2a that forms the left side of the housing 2. A cover unit 50 is provided to close the opening 70. Since the cover unit 50 is constructed by assembling a first cover 51, a second cover 52, and a third cover 53, it is sufficient to remove only the cover corresponding to the maintenance area. Because it is not necessary to remove the entire cover unit 50, the burden on the worker during maintenance work can be reduced.

[0060] In particular, to ensure safety, the interlock must not be released when the opening 70 is open. However, the state in which any of the three covers is removed (i.e., the opening 70 is open) can be detected by a single sensor 54. In other words, the open / closed state of the opening 70 can be detected with fewer sensors than the number of covers that make up the cover unit 50. This reduces the operational costs related to the interlock. It also contributes to saving space within the device.

[0061] [Differentiation] Figure 9 is a diagram showing the configuration of the cover unit 50 according to a modified example. In this modified example, the cover unit 150 includes a first cover 51, a second cover 52, and a third cover 153. The third cover 153 has a bottomed cylindrical bulge 153a and a flange portion 153b extending radially from the open end of the bulge 153a, forming a top hat shape. The outer diameter of the flange portion 153b is larger than the outer diameter of the third opening region 73. By adopting such a configuration, for example, it is possible to accommodate one end of the workpiece W inside the third cover 153 while ensuring the safety of the worker. It goes without saying that the cover unit is not limited to the configuration of the above embodiment and modified example, but can be any structure in which the cover unit can be composed of multiple covers.

[0062] [Other variations] In the above embodiment, with respect to the sensor 54, an example was shown in which the sensor body 80 is provided on the first cover 51 and the detection element 82 is provided on the third cover 53. In a modified example, the opposite may be true: the sensor body 80 (detection unit) may be provided on the third cover 53 and the detection element 82 (detected unit) may be provided on the first cover 51. In that case, the signal line 59 may be eliminated, and the sensor body 80 and the information processing device 100 may be wirelessly connected. Power to the sensor body 80 may be supplied by a battery or wireless power supply. The detection unit of the sensor and the detected unit of the sensor may be provided on the first cover and the other on the third cover.

[0063] In the above embodiment, an example was shown in which a first work spindle 20 and a second work spindle 22 are provided as work spindles, and the two are arranged opposite each other in the axial direction. In a modified example, a configuration without the second work spindle 22 may be adopted. A tailstock may be provided instead of the second work spindle 22.

[0064] In the above embodiment, the machine tool 1 was described as a turning center, but it may also be a combined machining center that combines the functions of both a turning center and a machining center. It may also be a turning center-based combined machining center capable of milling and turning.

[0065] When machine tool 1 is a multi-tasking machine, a tool spindle is provided instead of a turret (tool post). The tool spindle functions as a "tool holder" and is rotatably supported on the spindle head. The spindle head is driven in the X, Y, and Z directions by a moving mechanism. The multi-tasking machine is further provided with a tool storage unit and a tool changing unit. The tool storage unit includes a magazine for storing tools. The tool changing unit includes an ATC (Automatic Tool Changer) and, according to a change instruction from the machining control device 102, retrieves a tool from the tool storage unit and replaces it with the tool on the tool spindle.

[0066] It should be noted that the present invention is not limited to the embodiments and modifications described above, and the components can be modified and implemented without departing from the spirit of the invention. Various inventions may be formed by appropriately combining the multiple components disclosed in the embodiments and modifications described above. In addition, some components may be deleted from all the components shown in the embodiments and modifications described above. [Explanation of Symbols]

[0067] 1 Machine tool, 2 Housing, 2a Splash guard, 4 Machining chamber, 5 Storage chamber, 8 Coolant tank, 10 Mist collector, 12 Partition wall, 14 First spindle, 16 Second spindle, 18 Tool post, 20 First work spindle, 20a Chuck, 22 Second work spindle, 26 Turret, 28 Mist intake, 30 Piping, 34 Opening, 40 Support column, 42 Table, 46 Hood, 50 Cover unit, 51 First cover, 52 Second cover, 53 Third cover, 54 Sensor, 60 Bar feeder, 62 Chuck cylinder, 64 Sensor, 70 Opening, 71 First opening area, 72 Second opening area, 73 Third opening area, 80 Sensor body, 82 Detection element, 100 Information processing device, 102 Machining control device, 104 Machining device, 106 Detection unit, 108 Interlock unit, 110 Work spindle drive unit, 112 Tool post drive unit, 153 Third cover, W Work.

Claims

1. A splash guard with an opening for maintenance, A cover unit is assembled to the splash guard to close the aforementioned opening, A sensor for detecting the open / closed state of the opening, An interlock unit that restricts the driving of the main spindle when the open state of the aforementioned opening is detected, Equipped with, The aforementioned cover unit is A first cover is detachably attached to the splash guard to shield the first opening area of ​​the opening, A second cover is detachably attached to the splash guard separately from the first cover, thereby shielding the second opening area of ​​the opening. A third cover is detachably attached to the second cover, and when the second cover is attached to the splash guard, the third cover shields the third opening region of the opening formed between the first cover and the second cover. Includes, The sensor is provided between the first cover and the third cover of a machine tool.

2. The machine tool according to claim 1, wherein the third cover is capable of shielding the third opening region only when it is attached to the second cover.

3. The detection unit of the sensor is attached to the first cover. The part to be detected by the sensor is fixed to the third cover. The interlock unit acquires detection information from the sensor via a signal line connected to the detection unit. The machine tool according to claim 1 or 2, wherein the signal line is disconnected from the first cover when the first cover is removed.

4. The interlock unit acquires detection information from the sensor via a signal line connected to the sensor. The machine tool according to claim 1 or 2, wherein the signal line is disconnected from the cover unit when the cover unit is removed together with all or part of the splash guard, including the opening.

5. The aforementioned spindle includes a work spindle that supports the workpiece to be machined, A headstock is positioned adjacent to the inside of the splash guard and rotatably supports the workpiece spindle, Equipped with, In the state in which the cover unit is formed, The third cover is positioned axially opposite to the workpiece supported by the workpiece spindle, The machine tool according to claim 1 or 2, wherein the first cover and the second cover are arranged to surround the third cover.

6. The machine tool according to claim 1 or 2, wherein the sensor is a non-contact proximity sensor.

7. A splash guard having an opening for maintenance of a machine tool, A cover unit assembled to close the aforementioned opening, A sensor for detecting the open / closed state of the opening, Equipped with, The aforementioned cover unit is A first cover is detachably attached to the splash guard to shield the first opening area of ​​the opening, A second cover is detachably attached to the splash guard separately from the first cover, thereby shielding the second opening area of ​​the opening. A third cover is detachably attached to the second cover, and when the second cover is attached to the splash guard, the third cover shields the third opening region of the opening formed between the first cover and the second cover. Includes, The sensor is a splash guard provided between the first cover and the third cover.

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