Grinding coolant device

Abstract

To provide a technique which can efficiently separate sludge-like fine chips from a coolant and does not use a filter that becomes waste.SOLUTION: Chips in a coolant passing through a first tank 202A and a second tank 202B are suctioned to a permanent magnet 307B of an endless chain 302B and discharged to a chip box 308. The magnetic force of the permanent magnet 307A of an endless chain 302A is set to be stronger than the magnetic force of the permanent magnet 307B of the endless chain 302B. Therefore, fine chips in the coolant passing through a third tank 202C and a fourth tank 202D can be suctioned to the permanent magnet 307A of the endless chain 302A and discharged to the chip box 308. Therefore, when the coolant passing through the fourth tank 202D flows into a sub coolant tank 105, a coolant pump 107 supplies the coolant in the sub coolant tank 105 to a magnetic inline filter 10 to filter the coolant.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a coolant device for a machine tool. More specifically, it relates to a coolant device for grinding, which is used for separating fine sludge-like chips discharged during gear grinding.

Background Art

[0002] For coolant devices used in machine tools, an oil-based or water-soluble coolant is used for discharging chips from the cutting position, cooling the workpiece and the tool, and improving lubricity. Similarly, the coolant for gear grinding machines is also oil-based or water-soluble. In a water-soluble coolant device used for a gear grinding machine, in order to separate floating chips floating on the water-soluble coolant, a water-soluble coolant recirculation device for a grinding machine that blows them with an injection nozzle and efficiently removes them has been proposed (Patent Document 1). The gear grinding machine of Patent Document 1 uses a vitrified grinding wheel for grinding. On the other hand, in recent years, the tooth surfaces of gears such as those of automotive transmissions have been required to be smooth and have accurate dimensional accuracy. Furthermore, a highly productive grinding method is also required.

[0003] For this reason, instead of a vitrified grinding wheel, a CBN (cubic boron nitride) grinding wheel with high heat resistance and capable of high-speed grinding is used for the grinding wheel of the tooth surface of the gear. In the case of gear grinding using a CBN grinding wheel, since the chips are fine (sludge) for high-speed grinding, they usually do not float. However, after separating large magnetic chips from the coolant with a magnetic drum, it is necessary to further separate finer chips using a paper filter or the like. When using a paper filter, it takes time for regular replacement, and the paper filter must be treated as industrial waste, resulting in high costs, and the discharge of waste is not environmentally friendly. In addition, the coolant device described in Patent Document 1 uses a magnetic drum and a cyclone type filtration device. The cyclone type filtration device has the advantage of not discharging industrial waste.

[0004] In addition, a grinding fluid treatment device has been proposed for separating sludge-like so-called sludge in which metal chips, abrasive grains of grinding wheels, etc. contained in the coolant are mixed, using a roll grinding machine or the like (Patent Document 2). The grinding fluid treatment device of Patent Document 2 separates the tank into two tanks, flows the dirty coolant returned from the machine tool into one tank, and flows the purified coolant into the other tank. Further, the grinding fluid treatment device of Patent Document 2 arranges a magnet on the lower surface (outer surface) of the bottom plate of the grinding fluid storage container to separate magnetic swarf, and uses a chain-driven scraping plate member to remove sludge from the upper surface (inner surface) of the bottom plate. On the other hand, the applicant of the present application has proposed a magnetic in-line filter using the magnetic swarf itself as a filter (Patent Document 3). Since this magnetic in-line filter uses the magnetic swarf itself as a filter, it has the advantage of not requiring a filter that is a consumable and a waste product. Further, there is no need for backwashing or the like, and it is only necessary to flow the accumulated magnetic swarf with the coolant and discharge it.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the case of grinding gears using a CBN grinding wheel, an oil-based coolant is usually often used. When an oil-based coolant is used, fine chips with lipophilicity are coated with oil one by one. Therefore, in a magnetic drum type magnet separator as described in Patent Document 1, the chip recovery rate is low. This is presumably because the magnetization force of the chips is low due to being coated with oil, and they flow out from the magnet separator at the flow rate of the coolant. Also, a cyclone type filtration device has the advantage of not discharging industrial waste, but a dedicated pump is required for this, leading to energy loss. Furthermore, the cyclone type filtration device does not have high separation performance for fine chips coated with oil. The grinding fluid treatment device of Patent Document 2 eliminates sludge with a scraping plate member to separate magnetic chips, so the scraping plate member may wear and chips may mix into the coolant, and it is also necessary to periodically replace the worn scraping plate member.

[0007] The present invention achieves the following objects based on the above background. An object of the present invention is to provide a coolant device for grinding that can efficiently separate fine chips from a coolant. Another object of the present invention is to provide a coolant device for grinding that does not produce industrial waste. Still another object of the present invention is to provide a coolant device for grinding with little energy loss.

Means for Solving the Problems

[0008] To solve the above problems, the present invention adopts the following means. That is, the coolant device for grinding of the first aspect of the present invention is In a coolant device for grinding for separating chips from the coolant discharged from a grinding wheel (101), a non-magnetic coolant tank (102) that receives the coolant discharged from the grinding wheel and separates chips, It is disposed below the bottom plate (106) of the coolant tank (102), has permanent magnets (307A, 307B) arranged at a predetermined interval, and due to the magnetic force of the permanent magnets (307A, 307B), chips of magnetic material deposited on the bottom plate (106) of the coolant tank (102) are adsorbed, separated from the coolant, discharged, and is a magnetic chip conveyor having endless chains (302A, 302B) driven to rotate. The chips of magnetic material deposited on the bottom plate (106) are adsorbed, separated, and supplied minute swarf that is mixed into the coolant and does not precipitate Purified and supplied to the grinding machine (101), which is a double tube composed of a coaxial inner tube (1) and outer tube (2), and the coolant tank (102) adsorbs the swarf of the magnetic material that has precipitated on the bottom plate (106) before A cylindrical body (3) for flowing the separated coolant into the space that is the gap between the double tubes, an inner peripheral surface side magnet (4) disposed on the inner peripheral surface side of the inner tube (1), and an outer peripheral surface side magnet (5) disposed on the outer peripheral surface side of the outer tube (2), and a magnetic in-line filter (10) Characterized by comprising a pump (107) for supplying the coolant from which chips of magnetic material have been separated in the coolant tank (102) to the magnetic in-line filter (10).

[0009] The grinding coolant device of the second aspect of the present invention is, in the first aspect of the present invention, the coolant tank is composed of a plurality of liquid tanks partitioned by partition walls so that the coolant flows in one direction, and due to the magnetic force of the permanent magnet disposed below the bottom plate of the liquid tank on the upstream side of the flow of the coolant, the magnetic force of the permanent magnet disposed below the bottom plate of the liquid tank on the downstream side is stronger. The grinding coolant device of the third aspect of the present invention is, in the second aspect of the present invention, the plurality of liquid tanks are, along the flow of the coolant, the first tank , the second tank, the third tank, and to the fourth tank in order and the magnetic strength of the permanent magnet is the the first tank and the the second tank have the same magnetic strength, the the third tank and the the fourth tank are the the first tank and theIt is characterized by being stronger than the second groove and having the same strength. The coolant device for grinding according to the fourth aspect of the present invention is selected from the first to third aspects of the present invention. one invention In this case, the coolant is an oil-based coolant, and the grinding wheel is a gear grinding wheel for grinding a tooth surface with a CBN grinding wheel.

Advantages of the Invention

[0010] The coolant device for grinding of the present invention can efficiently separate fine chips from the coolant because it separates the chips in the coolant with a magnetic chip conveyor and a magnetic in-line filter.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Best Mode for Carrying Out the Invention

[0012] [Outline of Grinding Coolant Device] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall perspective view showing the grinding coolant device of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a view taken in the direction of arrow P of FIG. 2. FIG. 4 is a perspective view of the coolant tank of FIG. 1, showing a state where the lid on the upper surface is removed. FIG. 5 is a cross-sectional view taken along line A-A of FIG. 2 showing the coolant tank and the magnetic chip conveyor, with the equipment installed on the upper surface of the coolant tank omitted. FIG. 6 is a cross-sectional view taken along line B-B of FIG. 5, and FIG. 7 is a coolant circuit diagram of the grinding coolant device of the present invention. FIG. 8 is a longitudinal sectional view of the magnetic in-line filter, showing a state where the piston rod of the fluid cylinder is retracted to the uppermost position and coolant is supplied from the supply port near the upper end to the machining part. FIG. 9 shows a state where the piston rod of the fluid cylinder in FIG. 8 is extended to the lowermost position, coolant is discharged from the discharge port below, and the accumulated chips are discharged to the outside. As shown in FIGS. 1 to 9, chips ground by the CBN grinding wheel of the gear grinding machine 101 (FIG. 2) and chips washed away from the jig are collected by a chip conveyor (not shown) of the gear grinding machine 101 to collect large chips. Thereafter, the chips are collected together with the oily coolant into the coolant tank 102 through the coolant recovery gutters 104A and 104B.

[0013] [Structure of Coolant Tank] The coolant tank 102 is made of stainless steel (non-magnetic). As shown in Fig. 5, the right end is formed on an inclined surface that slopes upward to the right. At the lower part of the bottom plate 106 of the coolant tank 102, magnets are arranged on the magnetic chip conveyor 103. These magnets move in contact with the back surface of the bottom plate 106, adsorbing the magnetic chips deposited on the bottom plate 106 of the coolant tank 102, separating them from the coolant, and discharging them. On the side surface of the coolant tank 102 (the lower side in Fig. 2), a sub-coolant tank 105 is integrally formed. On the upper surface of the sub-coolant tank 105, a coolant pump 107 and a liquid level gauge 110 are placed. The liquid level gauge 110 detects the upper and lower limits of the coolant level in the sub-coolant tank 105 and displays an alarm on the screen of an operation panel (not shown) of the gear grinding machine 101.

[0014] On the upper surface of the coolant tank 102, two magnetic in-line filters 10 are placed. This magnetic in-line filter 10 was proposed by the applicant of this application, and its structure and function are well-known (Patent Document 3). The coolant pump 107 supplies the coolant in the sub-coolant tank 105 to the inlet 21 (see Figs. 7 to 9) of the magnetic in-line filter 10. As shown in Fig. 7, a pressure gauge 112 and a manual switching valve 113 are attached in the middle of the pipe 111 connecting the coolant pump 107 and the inlet 21. Since the chips in the coolant supplied to the inlet 21 are adsorbed by the magnetic field of the magnetic in-line filter 10, the coolant is filtered.

[0015] The filtered coolant is supplied from the supply port (coolant outlet) 22 of the magnetic in-line filter 10 to the machining part (contact position between the CBN grinding wheel and the gear) of the gear grinding machine 101 via the coolant supply pipe 114 (see Fig. 7), and grinding can be performed with clean coolant. In the middle of the coolant supply pipe 114, a flow switch 115 (see Fig. 7) for detecting the flow rate of the coolant flowing through the coolant supply pipe 114 is attached. It detects the lower limit of the flow rate and displays an alarm on the screen of an operation panel (not shown) of the gear grinding machine 101.

[0016] On the upper surface of the coolant tank 102, a mesh cage 116 is arranged. At the discharge port 23 (see FIGS. 7 to 9) of the magnetic in-line filter 10, a coolant discharge pipe 117 for discharging the coolant discharged from the discharge port 23 to the mesh cage 116 is connected. The mesh cage 116 separates and accumulates chips from the coolant, and returns the coolant from which the chips have been separated to the coolant tank 102. The chips accumulated in the mesh cage 116 are removed from the coolant tank 102 by removing the mesh cage 116 and periodically cleaned.

[0017] As shown in FIG. 4, the coolant tank 102 is composed of four liquid tanks (first tank 202A, second tank 202B, third tank 202C, fourth tank 202D) longitudinally partitioned by partition walls 201A, 201B, 201C. Further, weir plates are arranged in the transverse direction in the four first tanks 202A, second tanks 202B, third tanks 202C, and fourth tanks 202D. This weir plate is formed shorter than the depth of each tank. That is, a gap through which chips can pass is formed at the lower part of the weir plate. The weir plate prevents the turbulent flow of the coolant to and prevents the sludge-like chips from spreading. The coolant discharged from the gear grinding machine 101 flows into the first tank 202A of the coolant tank 102 through the coolant recovery gutters 104A and 104B. A plurality of openings 203A, 203B, 203C are respectively formed at the lower parts of the partition walls 201A, 201B, 201C. Further, two openings 203D are formed in the partition wall 201D between the coolant tank 102 and the sub-coolant tank 105. Therefore, when the coolant in the sub-coolant tank 105 is sucked up by the coolant pump 107, the coolant in the first tank 202A passes through the second tank 202B, third tank 202C, and fourth tank 202D in this order and flows into the sub-coolant tank 105. Note that the grinding coolant device of the present embodiment is energy-saving because only one coolant pump 107 performs the supply to the grinding machine and the filtration.

[0018] [Structure of Magnetic Chip Conveyor] As shown in FIG. 5, the bottom plate 106 of the coolant tank 102 is composed of a horizontal portion 106A, an inclined portion 106B, and a swarf dropping portion 106C. The magnetic chip conveyor 103 includes a box-shaped chip conveyor body 301 that is long in the left-right direction of FIG. 5, and the chip conveyor body 301 is disposed below the horizontal portion 106A, the inclined portion 106B, and the swarf dropping portion 106C of the bottom plate 106 of the coolant tank 102. As shown in FIG. 6, the width W1 of the chip conveyor body 301 is formed to be substantially the same dimension as the width W2 from the first tank 202A to the fourth tank 202D of the coolant tank 102. The chip conveyor body 301 is integrally formed by combining two chip conveyor bodies 301A and 301B having a width W3 that is 1 / 2 of the width W1. Endless chains 302A and 302B are wound around sprocket wheels 303 and 304 and disposed on the chip conveyor bodies 301A and 301B. Although not shown, the sprocket wheels 303 and 304 are rotatably supported on the chip conveyor bodies 301A and 301B, respectively. The sprocket wheel 303 of the chip conveyor body 301A and the sprocket wheel 303 of the chip conveyor body 301B are connected by a single rotating shaft (not shown) disposed in a direction perpendicular to the plane of FIG. 5. Similarly, the sprocket wheel 304 of the chip conveyor body 301A and the sprocket wheel 304 of the chip conveyor body 301B are also connected by a single rotating shaft (not shown) disposed in a direction perpendicular to the plane of FIG. 5. The sprocket wheel 303 at the right end of FIG. 5 on the chip conveyor body 301A side rotates clockwise by a motor 305, and the endless chains 302A and 302B move clockwise in FIG. 5.

[0019] A plurality of plate-shaped magnet holders 306A and 306B are respectively fixed to endless chains 302A and 302B at equal intervals in the longitudinal direction of the endless chains 302A and 302B. A permanent magnet (such as a rare earth permanent magnet) 307A is adhered and fixed to the magnet holder 306A of the endless chain 302A. Similarly, a permanent magnet (such as a rare earth permanent magnet) 307B is adhered and fixed to the magnet holder 306B of the endless chain 302B. A plurality of the permanent magnets 307A and 307B are respectively fixed in the left-right direction in FIG. 6. Since the thickness of the permanent magnet 307A is formed thicker than the thickness of the permanent magnet 307B, the magnetic force (magnetic flux density) of the permanent magnet 307A is set stronger than the magnetic force of the permanent magnet 307B. That is, it can also adsorb fine chips in the form of sludge.

[0020] [Operation of the Magnetic Chip Conveyor] When the sprocket wheel 303 rotates clockwise in FIG. 5 by the motor 305, the endless chains 302A and 302B move clockwise along the back surface of the bottom plate 106 of the coolant tank 102 in FIG. 5. Therefore, the chips deposited on the bottom plate 106 are attracted by the permanent magnets 307A and 303B and move to the right in FIG. 5. That is, the chips separated from the coolant move to the chip dropping portion 106C via the horizontal portion 106A and the inclined portion 106B. In the inclined portion 106B, the chips fall due to gravity. The endless chains 302A and 302B are reversed by the sprocket wheel 303 at the right end, and the permanent magnets 307A and 307B are separated from the chip dropping portion 106C, so the chips fall from the chip dropping portion 106C into the chip box 308.

[0021] The chips in the coolant passing through the first tank 202A and the second tank 202B are attracted by the permanent magnet 307B of the endless chain 302B and discharged into the chip box 308. However, minute chips remain in the coolant flowing into the third tank 202C. The magnetic force of the permanent magnet 307A of the endless chain 302A is set stronger than the magnetic force of the permanent magnet 307B of the endless chain 302B. Therefore, the minute chips in the coolant passing through the third tank 202C and the fourth tank 202D can be attracted by the permanent magnet 307A of the endless chain 302A and discharged into the chip box 308. However, since the minute chips mixed in the coolant do not precipitate, they cannot be processed by the magnetic chip conveyor 103. Therefore, when the coolant passing through the fourth tank 202D flows into the sub-coolant tank 105, the coolant pump 107 supplies the coolant in the sub-coolant tank 105 to the magnetic in-line filter 10 for further filtration.

[0022] [Structure of Magnetic In-line Filter] As shown in FIGS. 8 and 9, the magnetic in-line filter 10 has a cylindrical body 3 composed of an inner tube 1 and an outer tube 2 made of a non-magnetic material such as austenitic stainless steel. The cylindrical body 3 is composed of an inner circumferential surface side magnet 4 disposed on the inner circumferential surface of the inner tube 1, an outer circumferential surface side magnet 5 disposed on the outer circumferential surface of the outer tube 2, and a fluid cylinder 61 for axially moving the inner circumferential surface side magnet 4 and the outer circumferential surface side magnet 5.

[0023] The cylindrical body 3 is a double tube in which a cylindrical inner tube 1 and a cylindrical outer tube 2 are coaxially arranged. The axial length of the inner tube 1 is formed to be approximately twice the axial length of the outer tube 2, and the lower end of the inner tube 1 is fixed to a rectangular lower plate 71 by welding and erected vertically. The outer tube 2 is disposed above the inner tube 1, and the coolant flows through a space 31 which is the gap between the inner tube 1 and the outer tube 2. An upper lid 32 is welded to the upper end of the space 31, and a bottom lid 33 is welded to the lower end of the space 31 to integrate the inner tube 1 and the outer tube 2 and partition the space 31.

[0024] Near the lower end of the axial length of the outer tube 2, an inlet 21 for introducing coolant (sewage mixed with swarf) into the space 31 is formed. Near the upper end of the axial length of the outer tube 2, a supply port 22 for supplying the coolant purified in the space 31 to the processing section is formed. Further, in the outer tube 2, a discharge port 23 is formed below the inlet 21, and the discharge port 23 is an outlet for discharging the swarf accumulated in the space 31 to the outside of the space 31. A switching valve 231 operated by a solenoid is attached to the discharge port 23 to discharge the swarf to the mesh cage 116 of the coolant tank 102. When filtering the coolant, the switching valve 231 shuts off the discharge port 23. The bottom cover 33 is formed on an inclined surface that descends from the inlet 21 toward the discharge port 23, and the swarf is easily discharged to the outside from the discharge port 23.

[0025] On the inner peripheral surface 11 of the inner tube 1, an inner peripheral surface side magnet 4 is arranged with a slight gap from the inner peripheral surface 11. The inner peripheral surface side magnet 4 is composed of a plurality of magnets 42 fixed with an adhesive or the like. The magnet 42 is formed in a fan shape in the shape perpendicular to the axis, and a plurality (12) are arranged at equal angles (30 degrees) intervals over the entire circumference of the inner peripheral surface 11 of the inner tube 1, and are fixed to a cylindrical magnet holder 41. The magnets 42 are stacked in the axial direction by 10 and arranged over an axial length substantially the same as the axial length of the outer tube 2.

[0026] The inner peripheral surface side magnet 4 is movable in the axial direction of the inner tube 1 and is driven between a filtering position facing the space 31 and a swarf discharge position separated from the space 31. That is, between a rectangular lower plate 71 and a rectangular upper plate 72, three cylindrical guide rods 73 made of structural steel are vertically fixed. The upper plate 72 is arranged with a slight gap above the cylindrical body 3. The guide rod 73 passes through the magnet holder 41 and extends vertically, and is slidably assembled to cylindrical linear bushes 74, 74. The linear bushes 74, 74 are fixed to the upper end and the lower end of the magnet holder 41 by pressing plates 43, 43. The pressing plates 43, 43 are disk-shaped and are fixed to the upper end surface and the lower end surface of the magnet 42. A plurality of balls (not shown) are interposed between the guide rod 73 and the linear bushes 74, 74 so as to be able to roll, enabling a smooth linear motion.

[0027] A fluid cylinder 61 is fixed to the upper surface of the upper plate 72, and a piston rod 62 protruding from the lower end of the fluid cylinder 61 is screwed and fixed to the upper end surface of the magnet holder 41. Therefore, by switching the hydraulic pressure supplied to the fluid cylinder 61, the inner peripheral surface side magnet 4 is driven between the filtering position facing the space 31 and the chip discharge position separated from the space 31. On the outer peripheral surface 24 of the outer tube 2, an outer peripheral surface side magnet 5 is arranged with a slight gap from the outer peripheral surface 24. The outer peripheral surface side magnet 5 is composed of two semi-circular arc-shaped magnet holders 51, 51 and a plurality of magnets 52 fixed to the inner peripheral surfaces of the magnet holders 51, 51 with an adhesive. The magnet holders 51, 51 are formed to have an axial length substantially the same as the axial length of the outer tube 2 and are formed of a magnetic metal such as structural steel. The magnet 52 has a sector-shaped cross section in a direction perpendicular to the axis, and a plurality of magnets 52 are arranged at equal angular intervals over the entire circumference of the outer peripheral surface 24 of the outer tube 2. They are stacked in the axial direction in 10 layers and are arranged over an axial length substantially the same as the axial length of the outer tube 2.

[0028] The outer peripheral surface side magnet 5 is movable in the axial direction of the outer tube 2 and is driven between the filtering position facing the space 31 and the chip discharge position separated from the space 31. That is, between the rectangular lower plate 71 and the rectangular upper plate 72, four cylindrical guide rods 75 are vertically fixed. Two guide rods 75 penetrate each of the magnet holders 51, 51 and extend vertically, and are slidably assembled to cylindrical linear bushes 76, 76. The linear bushes 76, 76 are fixed to the upper and lower ends of the magnet holders 51, 51 by pressing plates 53, 53. The pressing plates 53, 53 are plates having a semi-circular arc-shaped cross section in a direction perpendicular to the axis and are fixed to the upper and lower end surfaces of the magnet holders 51, 51. A plurality of balls (not shown) are interposed between the guide rod 75 and the linear bushes 76, 76 so as to be capable of rolling movement, enabling a smooth linear movement.

[0029] The outer peripheral surface side magnet 5 is driven in synchronization with the inner peripheral surface side magnet 4. A pressing plate 53 at the lower end of the outer peripheral surface side magnet 5 and a pressing plate 43 at the lower end of the inner peripheral surface side magnet 4 are connected by a connecting plate 77 having a rectangular cross-section in a direction perpendicular to the axis. Therefore, by switching the hydraulic pressure supplied to the fluid cylinder 61, the inner peripheral surface side magnet 4 and the outer peripheral surface side magnet 5 are driven in synchronization between a filtering position facing the space 31 and a chip discharge position spaced apart from the space 31.

[0030] The magnet 42 of the inner peripheral surface side magnet 4 is fixed to a magnet holder 41 which is a magnetic body. For this reason, the magnetic field lines start from the N pole, come out into the air, and then terminate at the S pole. At this time, since the inner tube 1 made of a non-magnetic material is the closest to the magnet 42, the magnetic field lines are not bent. When chips flow into this magnetic field, they will be trapped on the outer peripheral surface 12 of the inner tube 1. Similarly, the magnet 52 of the outer peripheral surface side magnet 5 is fixed to a magnet holder 51 which is a magnetic body. For this reason, the magnetic field lines start from the N pole, come out into the air, and then terminate at the S pole. At this time, since the outer tube 2 made of a non-magnetic material is the closest to the magnet 52, the magnetic field lines are not bent. When chips flow into this magnetic field, they will be trapped on the inner peripheral surface 25 of the outer tube 2.

[0031] On one hand, the inner peripheral surface side magnet 4 and the outer peripheral surface side magnet 5 are arranged to face each other with different polarities. The magnet 42 of the inner peripheral surface side magnet 4 is set such that the outer peripheral surface side is the S pole and the inner peripheral surface side is the N pole. Also, the magnet 52 of the outer peripheral surface side magnet 5 is set such that the inner peripheral surface side is the N pole and the outer peripheral surface side is the S pole. Usually, it is known that when the N pole of another magnet is brought close to the vicinity of the S pole of a magnet, an attractive force acts. That is, magnetic field lines emerge from the N pole with a positive magnetic quantity and enter the S pole with a negative magnetic quantity. Therefore, between the magnet 52 of the outer peripheral surface side magnet 5 and the magnet 42 of the inner peripheral surface side magnet 4, magnetic field lines that emerge from the N pole with a positive magnetic quantity and enter the S pole with a negative magnetic quantity are formed. In this way, since the magnetic field in the radial direction becomes stronger, the swarf in the coolant is adsorbed to the wall surfaces on both sides of the space 31 (the outer peripheral surface 12 of the inner tube 1 and the inner peripheral surface 25 of the outer tube 2), and the adsorbed swarf accumulates and bridges. As a result, by passing the coolant through the gaps between the bridged swarf, precise filtration becomes possible. Also, since the magnetic field in the radial direction is strong and the swarf is efficiently adsorbed, a special filter member becomes unnecessary. In short, the swarf itself becomes a filter for the swarf.

[0032] [Operation of Magnetic Inline Filter] As shown in FIG. 8, the piston rod 62 of the fluid cylinder 61 is retracted to the uppermost position, and the inner peripheral surface side magnet 4 and the outer peripheral surface side magnet 5 are set at the filtration position facing the space 31. In this state, the solenoid of the switching valve 231 is actuated to block the discharge port 23. The coolant is introduced into the space 31 from the inlet 21 near the lower end of the outer tube 2, and the coolant is supplied to the gear grinding machine 101 from the supply port 22 near the upper end. Since the magnetic field in the radial direction is strong, the swarf in the coolant is adsorbed to the wall surfaces on both sides of the space 31, and the coolant is filtered. When the supply of the coolant continues, the swarf adsorbed to the wall surfaces accumulates and bridges. As a result, since the coolant passes through the gaps between the bridged swarf, precise filtration becomes possible.

[0033] When the machining of the gear grinding machine 101 is completed, as shown in Fig. 9, extend the piston rod 62 of the fluid cylinder 61 to the lowermost end, and move the inner circumferential surface side magnet 4 and the outer circumferential surface side magnet 5 to the chip discharge position far from the space 31. Accordingly, the magnetic force acting on the space 31 disappears, and the chips adsorbed on the wall surfaces on both sides of the space 31 are more likely to be detached from the wall surfaces of the space 31. Actuate the solenoid of the switching valve 231 to discharge the chips from the discharge port 23 to the mesh basket 116 of the coolant tank 102. That is, introduce the coolant into the space 31 from the inlet 21 near the lower end of the outer tube 2, and discharge the coolant from the discharge port 23 below the inlet 21. Since the bottom cover 33 is formed on an inclined surface that descends from the inlet 21 toward the discharge port 23, the chips accumulated in the space 31 are easily discharged to the outside from the discharge port 23. When discharging the chips, the switching valves 232, 233, and 234 shown in Fig. 7 can be switched, and the coolant can be supplied to the gear grinding machine 101 without passing through the magnetic in-line filter 10.

[0034] [Cooler, Mist Collector] As shown in Figs. 1 to 3, a cooler 118 for cooling the coolant to a predetermined temperature is attached to the left side of the coolant tank 102. Operate the manual switching valve 119 shown in Fig. 7 to supply the coolant to the cooler 118 for cooling. The cooled coolant is returned to the coolant tank 102 via the coolant recovery gutter 121. The mist collector 120 on the coolant tank 102 shown in Figs. 1 to 3 collects the mist filling the machining area of the gear grinding machine 101, keeps the working environment good, reduces the risk of fire, and purifies the environment.

[0035] The coolant device for grinding according to the embodiment of the present invention can efficiently separate fine chips from the coolant because it separates the chips in the coolant with a magnetic chip conveyor and a magnetic in-line filter. Further, the coolant tank of the coolant device for grinding according to the embodiment of the present invention is composed of a plurality of liquid tanks partitioned by partition walls so that the coolant flows in one direction, and the magnetic force of the permanent magnet arranged below the bottom plate of the liquid tank on the upstream side of the coolant flow is stronger than the magnetic force of the permanent magnet arranged below the bottom plate of the liquid tank on the downstream side. Therefore, first, the chips are attracted by the permanent magnet 307B of the endless chain 302B arranged below the bottom plate of the liquid tank on the upstream side and discharged into the chip box 308. Next, the minute chips in the coolant that could not be discharged on the upstream side can be attracted by the permanent magnet 307A of the endless chain 302A arranged below the bottom plate of the liquid tank on the downstream side and discharged into the chip box 308. Further, since the coolant device for grinding according to the embodiment of the present invention has no consumables such as paper filters, industrial waste and running costs are reduced. Furthermore, since the coolant device for grinding according to the embodiment of the present invention does not use pumps other than the coolant pump for processing, energy loss is small. Furthermore, since the coolant device for grinding according to the embodiment of the present invention does not require a scraping plate member for separating magnetic chips in the magnetic chip conveyor, there is no worn part and maintenance costs can be reduced.

Description of Reference Numerals

[0036] 10... Magnetic in-line filter 1... Inner tube 11... Inner peripheral surface 12... Outer peripheral surface 2... Outer tube 21... Inlet 22... Supply port 23... Outlet 231, 232, 233, 234... Changeover valves 24... Outer peripheral surface 25... Inner peripheral surface 3... Cylindrical body 31... Space (gap) 32... Upper lid 33... Bottom lid 4... Inner peripheral surface side magnet 41…Magnet holder 42…Magnet 43…Pressing plate 5…Outer peripheral surface side magnet 51…Magnet holder 52…Magnet 53…Pressing plate 61…Fluid cylinder 62…Piston rod 71…Lower plate 72…Upper plate 73…Guide rod 74…Linear bush 75…Guide rod 76…Linear bush 77…Connecting plate 101…Gear grinding machine 102…Coolant tank 103…Magnetic chip conveyor 104A, 104B…Coolant recovery gutter 105…Sub-coolant tank 106…Bottom plate 106A…Horizontal part 106B…Inclined part 106C…Chip dropping part 107…Coolant pump 110…Liquid level gauge 111…Pipe 112…Pressure gauge 113…Manual switching valve 114…Coolant supply pipe 115…Flow switch 116…Mesh cage 117…Coolant discharge pipe 118…Cooler 119…Manual switching valve 120…Mist collector 121…Coolant recovery gutter 201A, 201B, 201C, 201D…Partition wall 202A…First tank 202B…Second tank 202C…Third tank 202D…Fourth tank 203A, 203B, 203C, 203D…Opening 301, 301A, 301B... Chip conveyor body 302A, 302B... Endless chain 303, 304... Sprocket wheel 305... Motor 306A, 306B... Magnet holder 307A, 307B... Permanent magnet 308... Chip box

Claims

1. In a coolant device for grinding for separating chips from coolant discharged from a grinding machine (101), a non-magnetic coolant tank (102) for receiving the coolant discharged from the grinding machine and separating chips; a magnetic chip conveyor having endless chains (302A, 302B) which are disposed below a bottom plate (106) of the coolant tank (102) at a predetermined interval and are rotationally driven, and which adsorb magnetic chips deposited on the bottom plate (106) of the coolant tank (102) by the magnetic force of permanent magnets (307A, 307B) disposed at a predetermined interval, separate the chips from the coolant, and discharge the chips; a magnetic in-line filter (10) which is composed of a double tube including an inner tube (1) and an outer tube (2) disposed coaxially, and which purifies minute chips that are mixed into the coolant from which the magnetic chips deposited on the bottom plate (106) are adsorbed and separated and do not deposit, and supplies the purified coolant to the grinding machine (101), and includes a cylindrical body (3) for flowing the coolant from which the magnetic chips deposited on the bottom plate (106) of the coolant tank (102) are adsorbed and separated into a space which is a gap between the double tubes, an inner peripheral surface side magnet (4) disposed on an inner peripheral surface side of the inner tube (1), and an outer peripheral surface side magnet (5) disposed on an outer peripheral surface side of the outer tube (2); a pump (107) for supplying the coolant from which the magnetic chips are separated in the coolant tank (102) to the magnetic in-line filter (10); and characterized by comprising the above components.

2. The coolant device for grinding according to Claim 1, wherein the coolant tank is composed of a plurality of liquid tanks partitioned by partition walls such that the coolant flows in one direction, and the magnetic force of a permanent magnet disposed below a bottom plate of the liquid tank on the downstream side is stronger than the magnetic force of a permanent magnet disposed below a bottom plate of the liquid tank on the upstream side of the flow of the coolant. and characterized by the above.

3. In the coolant device for grinding according to claim 2, the plurality of liquid tanks are, in the order of a first tank, a second tank, a third tank, and a fourth tank, along the flow of the coolant, and the magnetic intensity of the permanent magnet is such that the first tank and the second tank have the same magnetic intensity, and the third tank and the fourth tank are stronger and have the same intensity than the first tank and the second tank A coolant device for grinding, characterized in that.

4. In the coolant device for grinding according to any one of claims 1 to 3, the coolant is an oil-based coolant, and the grinding machine is a gear grinding machine for grinding a tooth surface with a CBN grinding wheel A coolant device for grinding, characterized in that.

Images