Coolant supply system

Abstract

A coolant supply device (1, 40) comprising the following: a nozzle (27) from which coolant exits, a motor (4) that adjusts the rotation angle of the nozzle (27), a case (14), a hollow shaft (18, 41) which is rotatably and fluid-tightly inserted into the housing (14), wherein the hollow shaft (18, 41) has a coolant channel (23) inside it, an opening (24) which is arranged on a side wall of the hollow shaft (18, 41) and which is connected to the coolant channel (23), and an inlet channel (25) which is arranged in the housing (14) and is connected to the coolant channel (23) through the opening (24), wherein the nozzle (27) is connected to the hollow shaft (18, 41) and is in communication with the coolant channel (23), characterized in that the hollow shaft (18, 41) is directly connected to the output shaft of the motor and is arranged coaxially with it, or the hollow shaft (41) and the output shaft of the motor are formed in one piece; and that the hollow shaft is supported in bearings (19, 20) which are attached to both ends of the housing (14) and a stepped opening area which penetrates the housing (14) and which includes a large diameter bore (15A) and a small diameter bore (15B), and the hollow shaft (18) is sealed by O-rings (21, 22).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The present invention relates to a coolant supply device for supplying cooling liquid into the machining area of ​​a workpiece when a workpiece is machined with a machining machine. 2. State of the art

[0002] Generally, in machining operations such as cutting or grinding, machining is performed by supplying coolant to the machining area of ​​the workpiece for lubrication, cooling, chip removal, and metal adhesion prevention. In machining, it is desirable to correctly supply the coolant to the machining areas of the workpiece to ensure the stability and precision of the process. As described in Japanese Patent Application Laid-Open No. 2002-18674 and US Patent No. 6,772,042 B1, various types of coolant supply devices with adjustable coolant nozzle angles have been proposed for automatic machine tools such as machining centers or other NC machine tools.With this type of coolant supply device, which allows the angle of the coolant nozzle to be automatically adjusted as the metalworking process progresses, the coolant is correctly supplied to the machining area of ​​the workpiece.

[0003] In the above types of coolant supply systems, a nozzle from which the coolant emerges is driven in a rotating motion by a servo motor. By adjusting the position and angle of the nozzle after a tool change or according to the progress of the machining process, the coolant is precisely supplied to the machining area of ​​the workpiece.

[0004] Since the coolant supply device is exposed to coolant droplets or chip dispersion during machining, the servo motor that moves the nozzle, the reduction gear, and the like must be equipped with sufficient waterproof and dust-proof properties. Furthermore, since the coolant supply device must be housed in a limited space in automatic machine tools, such as machining centers or other NC machine tools, a reduction in the size of the coolant supply device has been required.

[0005] DE 32 41 208 A1 discloses a machine tool with a supply device for coolant and / or lubricant, which has an automatic control by means of which the position of a spray nozzle 4 can be automatically changed by means of a stepper motor, so that the spray nozzle is always aligned, regardless of the position of the workpiece or tool, so that a coolant and / or lubricant jet hits the tool cutting edge or contact zone between the tool and the workpiece.

[0006] DE 33 38 434 A1 discloses a spray device for the cutting fluid of a machine tool, comprising a rotary drive mounted at a suitable location on the machine tool, a nozzle mounted on the output shaft of the rotary drive, a stepper motor suitable for driving the rotary drive, and a control section connected to the numerical control unit of the machine tool. The control section controls the stepper motor according to the signals relating to the cutting tool to change the angle of the nozzle to a suitable position.

[0007] DE 103 33 981 A1 discloses a controlled coolant spray nozzle that automatically positions the coolant jet on the tool cutting edge during each tool change. The controlled coolant spray nozzle contains a servo motor that is positioned by an external control unit. The cooling nozzle control unit calculates the current angular position of the tool in the work spindle using the tool data from the CNC control. However, the position for each tool can also be saved via a CNC command or a button. Controlled coolant spray nozzles increase tool life through optimized cutting edge cooling, which is achieved by consistently maintaining the same position of the nozzles and by higher coolant pressure. Setup time and the risk of accidents are reduced.

[0008] DE 94 17 060 U1 discloses a cooling device for machine tools with tools of different lengths and changing working positions. It includes at least one nozzle, which is adjustably mounted on a pivoting nozzle block for jet pre-adjustment and can be electromechanically moved into the required jet position. The nozzle block is attached to a pivoting element in such a way that it can be adjusted radially to the pivot axis of the pivoting element. DISCLOSURE OF THE INVENTION

[0009] The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a coolant supply device which has excellent waterproof and dustproof properties while meeting the requirements of downsizing.

[0010] The inventive embodiments below illustrate some structural features of the present invention and are listed individually for a better understanding of the various structures of the present invention. These individual features do not limit the technical scope of the present invention. To best carry out the present invention, even if components of the individual parts are partially replaced or removed, or if components are added, these components are to be considered as part of the technical scope of the present invention.

[0011] To achieve the above-mentioned object, the present invention provides a coolant supply device according to claim 1. Advantageous further developments are defined in the dependent claims. The coolant supply device comprises a nozzle from which coolant emerges, and a motor that adjusts the angle of rotation of the nozzle. The coolant supply device further includes a housing, a hollow shaft that is rotatably and fluid-tightly inserted into the housing and in which a coolant channel is located, an opening that is arranged on a side wall of the hollow shaft and that communicates with the coolant channel, and an inlet channel that is arranged in the housing and communicates with the coolant channel via the opening. The nozzle is connected to the hollow shaft and communicates with the coolant channel. The hollow shaft is directly connected to an output shaft of the motor and arranged coaxially therewith.

[0012] Since the coolant supplied from the inlet port flows through the opening located on the side wall of the hollow shaft into the coolant port of the hollow shaft, the stationary inlet port does not need to be directly connected to the rotating hollow shaft by means of joints. This prevents coolant leakage due to defective joints. Furthermore, since the coolant is conveyed to the nozzle through the hollow shaft, the dimensions of the coolant supply device can be reduced. Furthermore, since the number of parts requiring sealing is minimized, the drip-proof and dust-proof properties can be improved.

[0013] In one embodiment of the present invention, the hollow shaft and the output shaft of the motor are formed in one piece.

[0014] Due to the integration of the hollow shaft and the output shaft of the motor, the number of components can be reduced.

[0015] In one embodiment of the present invention, the motor is a stepper motor.

[0016] Since the stepper motor is used, it is possible to use an open control loop, which contributes to simplifying the control circuit. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a coolant supply device according to the first embodiment of the present invention, Fig. 2 is a cross-sectional drawing of the coolant supply device along a line AA, Fig. 3 is a plan view of the coolant supply device with a cover removed, Fig. 4 is a perspective view of the coolant supply device with the cover removed, Fig. 5 is an exploded view of the coolant supply device, Fig. 6 is a cross-sectional view of a coolant supply device according to the second embodiment of the present invention, and Fig. 7 is an exploded view of the coolant supply device of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The embodiments of the invention will be explained below with reference to the accompanying drawings. At the outset, the first embodiment of the present invention will be explained with reference to the Fig. 1 to 5. A coolant supply device 1 of the first embodiment is mounted on an NC (numerically controlled) machine tool such as an NC drilling machine, an NC milling machine, an NC lathe, a machining center, etc., to supply coolant to the machining area of ​​the workpiece. In the coolant supply device 1, an adjustable nozzle unit 3 and a motor 4 are completely housed in a housing 2.

[0018] The housing 2 looks approximately like a rectangular body and consists of a box-shaped housing main body 5, which has one open side, and a cover 6 that closes the open side of the housing main body 5. In the housing 2, a rectangular fastening part 7 is formed integrally with the housing main body 5. The fastening part 7 forms a flat plate that extends in extension of the cover 6. The fastening part 7 is provided with a pair of elongated holes 8 through which the housing 2 is attached to automatic machine tools, etc.

[0019] The interior of the housing 2 is divided by a partition plate 9, which is formed integrally with the housing main body 5 and extends in the longitudinal direction. Furthermore, a cable chamber 10 is formed in the housing main body 5 next to the chamber in which the adjustable nozzle unit 3 and the motor 4 are housed. The cable chamber 10 serves for the wiring of the connecting lines connected to the motor 4. Approximately U-shaped cutouts 11, 12 are formed respectively on the partition plate 9 and the side wall 5A of the housing main body 5 (the side wall closer to the adjustable nozzle unit 3). An opening 13 (see Fig. 2) is on the side wall 5B (see also Fig. 2) of the housing main part 5 opposite cutout 12 of the partition plate 9. At the end of the housing main part 5 where the motor 4 is located, a recess 9A is formed for connecting the connecting cable to the motor 4.

[0020] The cover 6 is attached to the open side of the housing main body 5 by known fastening means (not shown) such as screws, fasteners, adhesives, etc. The housing main body 5 and the cover 6 are sealed to each other by known sealing methods (not shown) such as a gasket. The cover 6 is preferably attached to the housing main body 5 in such a way that it can also be removed again, using detachable fastening means such as screws and the like. The housing 2 is made of any suitable material, such as synthetic resin, aluminum alloy, steel, etc.

[0021] The adjustable nozzle unit 3 consists of a housing 14 whose outer shape represents an approximately rectangular body. A stepped opening portion, including a large-diameter bore 15A and a small-diameter bore 15B, penetrates the housing 14. A cylindrical guide member 16 is fluid-tightly fitted into the large-diameter bore 15A, while a nozzle chamber 17 is formed between the small-diameter bore 15B and the guide member 16. A hollow shaft 18, which penetrates the housing 14, is rotatably and fluid-tightly inserted into the small-diameter bore 15B and the guide member 16. The hollow shaft 18 is rotatably supported by bearings 19, 20 mounted at both ends of the housing 14. The hollow shaft 18 and the small diameter bore 15B, and the hollow shaft 18 and the guide part 16 are each sealed by an O-ring 21 and an O-ring 22, respectively.

[0022] The hollow shaft 18 has a coolant channel 23 that extends along the central axis of the hollow shaft 18. One end of the coolant channel 23 is open at one end of the hollow shaft 18, while the other end of the channel is closed. Furthermore, a plurality of openings 24 are provided on the side wall of the hollow shaft 18, which establish a connection between the coolant channel 23 and the nozzle chamber 17. The side wall of the housing 14 is provided with an inlet channel 25 for connection to the nozzle chamber 17, which inlet channel 25 communicates with a cylindrical inlet pipe 26. A nozzle 27 is attached to the open end of the hollow shaft 18, with the nozzle 27 being aligned at a right angle to the hollow shaft 18. Thus, the coolant channel 23 communicates with the interior of the nozzle 27. A projecting connecting portion 28 with two flat surfaces is formed at the closed end of the hollow shaft 18.At the end of the housing 14 (on the side where the large-diameter bore 15A is located), a rear cover 29 with an opening is attached. The closed end of the hollow shaft 18 is inserted into the opening of the rear cover 29. The adjustable nozzle unit 3 is mounted on the housing main body 5 such that 1) the open end of the hollow shaft 18, to which the nozzle 27 is connected, is inserted into the cutout 11, and 2) the inlet pipe 26 is inserted into the cutout 12 and the opening 13.

[0023] The motor 4 is designed so that its external shape is that of a rectangular body, similar to the nozzle unit 3. Furthermore, one end of the output shaft 30 is provided with a groove-shaped connecting portion 31, which is engaged by the projecting connecting portion 28 arranged at the closed end of the hollow shaft 18. The motor 4, which can be a known servo motor or stepper motor, controls the rotation angle of the output shaft 30. The stepper motor can also be of a variable reluctance type or a permanent magnet type, or a hybrid type that is a combination of the two aforementioned types. In the present embodiment, a hybrid stepper motor is used because the adjustable step angle is sufficiently small. A connecting line (not shown) that supplies the control current is connected to the motor 4.The connecting line extends into the cable chamber 10, passing through the recess 9A of the partition plate 9, and is further connected to an external drive circuit (not shown) via an electrical connection element (not shown) attached to the outer wall of the housing 2.

[0024] In the motor 4, the front cover 32 engages with the rear cover 29 of the adjustable nozzle unit 3, while the rear cover 33 of the motor 4 is adjacent to and fixed to the inner surface of the side wall 5C of the housing main body 5. In Fig. 2, reference numeral 34 indicates a rotor connected to the output shaft 30, reference numeral 35 is a stator arranged to face the outer periphery of the rotor 34, and reference numeral 36 is a bearing that rotatably supports the output shaft 30.

[0025] The adjustable nozzle unit 3 and the motor 4 are completely housed in the housing main body 5 in such a way that the output shaft 30 of the motor 4 is inserted into the rear cover 29 on the side of the adjustable nozzle unit 3, and the connecting portion 31 of the output shaft 30 engages the connecting portion 28 of the hollow shaft 18. The adjustable nozzle unit 3 and the motor 4 are then both fixed in the housing 2 by attaching the cover 6 to the opening of the housing main body 5. Here, the outline of the connecting portion 28 of the hollow shaft 18 and the outline of the connecting portion 31 of the output shaft 30 are not limited to the two-surface configuration described above. As long as the connecting portion 28 and the connecting portion 31 are capable of transmitting the rotation of the output shaft 31 to the hollow shaft 18, any other configuration is also usable.

[0026] While the nozzle 27 is aligned in the correct direction, the thus constructed coolant supply device 1 is installed in automatic machine tools such as machining centers or other types of NC machine tools by inserting bolts into the elongated holes 8 of the mounting part 7. The inlet pipe 26 is connected to the coolant supply, which includes a pump or the like, while the motor 4 is connected to the drive circuit that supplies the control current.

[0027] The coolant is then conveyed to the inlet pipe 26, the inlet channel 25, the nozzle chamber 17, the openings 24, and the coolant channel 23, and exits the nozzle 27. By rotating the output shaft 30 of the motor 4, the angle of rotation of the hollow shaft 18, which is connected to the output shaft 30, can be controlled. Accordingly, the angle of the nozzle 27 can be adjusted, allowing the coolant to be directed in any desired direction. It is also possible to dispense with the nozzle chamber 17, which is arranged within the housing 14. With this design, the coolant can then be guided directly from the inlet channel 25 to the openings 24 of the hollow shaft 18.

[0028] If it is necessary to adjust the initial position of the rotation angle (zero adjustment) of the hollow shaft 18 or the output shaft 30 of the motor 4, a Hall element (not shown) can be mounted on the hollow shaft 18 or the output shaft 30. The zero adjustment can be performed according to the detected rotation angle position. Alternatively, the zero adjustment can be performed by limiting the rotation range of the nozzle 27 with a stopper. The nozzle 27 is rotated until it abuts the stopper, and the zero adjustment is performed based on the position where the nozzle 27 abuts the stopper.

[0029] With the arrangement described above, the rotation angle of the nozzle 27 can be adjusted according to a change in the tool end position after a tool change in the automatic machine tool or according to a change in the distance between the nozzle and the machining position during the progress of machining. This allows the coolant to be precisely supplied to the specified machining position. Since a stepper motor is used as the motor 4, an open-loop control is possible. Compared with a closed-loop control of a servo motor, it is possible to further simplify the motor control circuit.

[0030] When controlling the rotation angle of the nozzle 27, in addition to adjusting the nozzle angle to precisely align the coolant with the cutting zone, the nozzle 27 can also be intentionally rotated at a large angle so that the coolant can effectively remove the chips from the cutting zone. Furthermore, the rotation of the nozzle can be carried out at a constant speed or a variable speed. Furthermore, when a stepping motor is used as the motor 4, the control codes of NC machine tools for tool change or tool specification (i.e., M codes or T codes) can be used as control signals for the motor 4. This makes it possible to adjust the rotation angle of the nozzle 27 to follow the machining area and contributes to simplifying the drive circuit of the coolant supply device.

[0031] By allowing coolant to flow into the coolant channel 23, which is arranged within the hollow shaft 18 that rotates the nozzle 27, a miniaturization of the coolant supply device 1 can be achieved, in particular a reduction in its axial dimensions. Furthermore, by largely avoiding areas that require sealing, drip-proof and dust-proof properties are significantly improved. Because the cover 6 is a removable part, it is possible to replace or repair the adjustable nozzle unit 3 or the motor 4 individually, even if only one of them is defective. This allows for a high level of ease of maintenance.

[0032] Next, the second embodiment of the present invention will be described with reference to Fig. 6 and Fig. 7. Here, like parts mentioned in the first embodiment of the present invention are designated by the same reference numerals, and only parts not described in the first embodiment will be explained in detail.

[0033] As shown in the pictures Fig. 6 and Fig. 7, in the coolant supply device 40, the hollow shaft 18 of the adjustable nozzle unit 3 and the output shaft 30 of the motor 4 of the first embodiment are designed in one piece with each other and thereby form a hollow motor shaft 41. As in the example of Fig.As shown in Figure 7, the hollow motor shaft 41 is already pre-assembled in the motor 4 and is then inserted into the adjustable nozzle unit 3. Alternatively, the hollow shaft of the motor 41 can first be attached to the adjustable nozzle unit 3 and then inserted or pressed into the motor 4. Due to this structure, the coolant supply device according to the second embodiment has the same advantageous properties as the first embodiment. List of reference symbols: 1 coolant supply device 2 housings 3 Adjustable nozzle unit 4 Engine 5 Main housing part 5A side wall 5B side wall 5C side wall 6 Cover 7 Fastening part 8 Elongated hole 9 Dividing plate 9A recess 10 cable chamber 11 Excerpt 12 Excerpt 13 Opening 14 housings 15A large diameter bore 15B small diameter hole 16 Guide part 17 Nozzle chamber 18 hollow shaft 19 camps 20 warehouses 21 O-ring 22 O-ring 23 Coolant channel 24 Opening 25 Inlet channel 26 Inlet pipe 27 nozzle 28 connecting section 29 Rear cover 30 Output shaft 31 connecting section 32 Front cover 33 Rear cover 34 Rotor 35 Stator 36 warehouses 40 Coolant supply device 41 Hollow shaft of the motor

Claims

[1] A coolant supply device (1, 40) comprising: a nozzle (27) from which coolant emerges, a motor (4) which adjusts a rotation angle of the nozzle (27), a housing (14), a hollow shaft (18, 41) which is rotatably and fluid-tightly inserted into the housing (14), wherein the hollow shaft (18, 41) has a coolant channel (23) in its interior, an opening (24) arranged on a side wall of the hollow shaft (18, 41) and communicating with the coolant channel (23), and an inlet channel (25) arranged in the housing (14) and communicating with the coolant channel (23) through the opening (24), wherein the nozzle (27) is connected to the hollow shaft (18, 41) and is connected to the coolant channel (23), characterized bythat the hollow shaft (18, 41) is directly connected to the output shaft of the motor and arranged coaxially therewith or the hollow shaft (41) and the output shaft of the motor are formed in one piece; and that the hollow shaft is mounted in bearings (19, 20) which are mounted at both ends of the housing (14), and a stepped opening area which penetrates the housing (14) and which includes a large diameter bore (15A) and a small diameter bore (15B), and the hollow shaft (18) are sealed by O-rings (21, 22). [2] A coolant supply device (1, 40) comprising: a nozzle (27) from which coolant emerges, a motor (4) which adjusts a rotation angle of the nozzle (27), a housing (14), a hollow shaft (18, 41) which is rotatably and fluid-tightly inserted into the housing (14), wherein the hollow shaft (18, 41) has a coolant channel (23) in its interior, an opening (24) arranged on a side wall of the hollow shaft (18, 41) and communicating with the coolant channel (23), an inlet channel (25) arranged in the housing (14) and communicating with the coolant channel (23) through the opening (24), and a nozzle chamber (17), wherein the hollow shaft (18, 41) extends through the nozzle chamber (17) and the connection between the opening (24) in the hollow shaft (18) and the inlet channel (25) is arranged in the nozzle chamber, wherein the nozzle (27) is connected to the hollow shaft (18, 41) and is connected to the coolant channel (23), wherein the hollow shaft (18, 41) is directly connected to the output shaft of the motor and arranged coaxially therewith, or the hollow shaft (41) and the output shaft of the motor are formed in one piece; and the nozzle (27) is designed to be pivoted at a large angle in order to remove chips from the cutting zone with the aid of the escaping coolant. [3] Coolant supply device (1, 40) according to claim 2, wherein the housing (14) has a bore with a large diameter (15A) and a bore with a small diameter (15B), a guide part (16) is fitted into the large diameter bore (15A); the nozzle chamber (17) is formed in the large diameter bore (15A) between the small diameter bore (15B) and the guide part (16). [4] A coolant supply device (1, 40) according to one of claims 1 to 3, wherein the motor (4) is a stepper motor.

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