JP4127247B2 - Grinding equipment - Google Patents

Description

  The present invention relates to a grinding apparatus that performs grinding work by blocking an air layer associated with a grinding wheel that rotates around the outer periphery of a grinding surface of a grinding wheel and reliably attaching a coolant flow to the grinding surface.

  In recent years, with the increase in processing speed, grindstones using high-hardness superabrasive grains such as diamond and CBN have been developed. When this superabrasive grindstone is used, the peripheral speed of the grindstone can be increased to 100 m / s or more. Further, when grinding a workpiece with a grindstone, it is necessary to prevent grinding burn, thermal distortion, etc. of the workpiece due to grinding heat by supplying a coolant to the grinding point between the workpiece and the grinding wheel to cool and lubricate.

  By the way, it is known that when the grindstone rotates, air around the grindstone is rotated to form an air layer associated with the grindstone, and this grindstone-associated air layer becomes stronger as the peripheral speed of the grindstone increases. As described above, when the superabrasive grindstone is rotated at a high speed, a strong grindstone-associated air layer is generated around the grindstone, so the grindstone-associated air layer prevents entry of coolant supplied from the outside and the coolant is ground. Could not supply enough. For this reason, in order to sufficiently supply the coolant to the grinding point, a technique as described in Patent Document 1 has been conventionally developed.

As shown in FIG. 1 of Patent Document 1, the technique described in Patent Document 1 is arranged at a position upstream of the rotation direction of the grindstone 14 from a supply point at which the fluid nozzle (first nozzle) 38 supplies coolant. In addition, an air shielding plate 50 for blocking the grinding wheel-associated air layer is provided to eliminate the grinding wheel-associated air layer in the vicinity of the coolant supply point so that the coolant reliably reaches the grinding point between the workpiece and the grinding wheel. . Moreover, as described in Patent Document 1, in order to block the air layer associated with the grindstone, the gap between the tip of the air shielding plate 50 and the outer peripheral surface of the grindstone 14 should be maintained at 0.2 mm or less. is necessary.
JP-A-6-155300 (3rd page paragraph number [0018] to 4th page paragraph number [0020], same page paragraph number [0027], FIGS. 1 and 5)

  The grindstone diameter decreases with use, and it is necessary to adjust the gap between the air shielding plate and the grindstone outer periphery as the grindstone diameter decreases. For this reason, in Patent Document 1, an AE sensor 70 for detecting the contact state between the air shielding plate 50 and the outer periphery of the grindstone is mounted on the air shielding plate 50, and a pulse motor 64 for moving the position of the air shielding plate 50 is provided. The position of the air shielding plate 50 is moved by the pulse motor 64 so that the contact signal from the AE sensor 70 becomes a predetermined value.

  However, when configured as in Patent Document 1, the AE sensor 70, the pulse motor 64, and the controller 72 that controls them are required, and there is a problem that the apparatus becomes large. In general, the grindstone is surrounded by a grindstone guard. However, in recent years, the size of the grindstone guard tends to be reduced in order to make the entire grinding apparatus compact. It has become difficult to store. Further, the AE sensor may malfunction due to detection of ambient vibration such as vibration when grinding a workpiece.

  Therefore, according to the present invention, an appropriate gap can be formed between the air shielding plate and the grinding surface of the grindstone with a simple configuration regardless of changes in the diameter of the grindstone, and the air layer associated with the grindstone can be reliably blocked. The purpose is to do.

  The structural feature of the invention described in claim 1 for solving the above-described problem is that a grindstone is rotatably supported on a grindstone table, and a workpiece support device and a grindstone table are supported relative to each other so that the workpiece can be rotationally driven. In a grinding device that moves and grinds a workpiece with a grinding surface while supplying fluid by a fluid supply device, a grinding wheel-associated air layer that rotates with the grinding wheel at a position upstream of the grinding point where the grinding wheel contacts the workpiece in the grinding wheel rotation direction Air shield plate is provided to shut off the air, and a holding means is provided to hold the air shield plate so that it can move in the direction of contact with and away from the grinding surface of the grindstone, and the air shield plate is biased in the direction of approaching the grinding surface. An urging means is provided, and a buoyancy is imparted to the air shielding plate by the air flow in the air layer accompanying the grindstone to form a minute gap between the air shielding plate and the grindstone surface against the urging force of the contact urging means. The buoyancy imparting part In the provision on the site of Kezumen facing the air shield.

  According to a second aspect of the present invention, in the first aspect, the holding member supports the air shielding plate so as to be pivotable around a support shaft formed in parallel with the grinding surface, and the contact biasing means is In addition, the rotational force about the support shaft is urged to the air shielding plate so that the buoyancy imparting portion approaches the grinding surface of the grindstone against the flow of the air layer accompanying the grindstone.

  The structural feature of the invention described in claim 3 is that, in claim 1 or 2, the air shield plate is slightly upstream of the position where the buoyancy imparting portion of the air shield plate faces the grinding surface of the grindstone. A fluid jet ejecting device that sprays a fluid jet toward the air is provided, and a fluid jet ejecting control unit that sprays the fluid jet from the fluid jet ejecting device toward the air shielding plate when the grinding wheel starts and stops rotating is provided. is there.

  According to a fourth aspect of the present invention, there is provided a movement restricting device for restricting the movement of the air shielding plate in the direction of contacting or separating from the grinding surface of the grindstone according to the first or second aspect. The movement of the air shielding plate is restricted during the stop, and a restriction control device is provided for controlling the movement restricting device so as to allow the movement of the air shielding plate at least during the rotation of the grindstone.

  According to a fifth aspect of the present invention, there is provided a movement restricting device for restricting the movement of the air shielding plate in a direction contacting or separating from the grinding surface of the grindstone. It is provided with a restriction control device that operates the movement restriction device only when the surface is corrected to allow the movement of the air shielding plate.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the fluid nozzle of the fluid supply device is formed integrally with the air shielding plate.

  In the invention according to claim 1 configured as described above, the air flow in the air layer associated with the grindstone acts between the outer peripheral grinding surface of the grindstone of the air shielding plate and the buoyancy imparting portion facing the outer peripheral grinding surface. By generating dynamic pressure and generating buoyancy in the air shielding plate by this dynamic pressure, an appropriate numerical value (0...) Is obtained between the outer peripheral grinding surface and the air shielding plate with a simple configuration regardless of the diameter of the grindstone. 2 mm or less) can be formed.

  In the invention according to claim 2 configured as described above, if the air shielding plate is swiveled around the support shaft, the movement in the direction approaching the grinding surface of the air shielding plate can be achieved with a simple configuration and without resistance. Can be done.

  In the invention which concerns on Claim 3 comprised as mentioned above, rotation of a grindstone is slow by supplying an air jet between an outer periphery grinding surface and a buoyancy provision part in rotation start of a grindstone, and a rotation stop. When sufficient buoyancy due to the air layer associated with the grindstone cannot be obtained, contact between the grindstone and the air shielding plate is prevented. As a result, the air shielding plate can be prevented from being scraped in contact with the grindstone when the grindstone starts and stops rotating.

  In the invention according to claim 4 configured as described above, even if the rotation of the grindstone is stopped, the movement restricting device maintains a minute gap between the outer peripheral grinding surface and the buoyancy imparting portion. It is possible to prevent scraping by contacting the grindstone at the start and stop of rotation. Further, the change in the diameter of the grindstone during grinding does not affect the appropriate minute gap between the grinding surface and the buoyancy imparting portion. Therefore, it is possible to adjust the minute gap to an appropriate amount by releasing the restriction of the movement of the air blocking plate at a time when the rotation of the grindstone becomes a constant speed rotation and again restricting the movement of the air blocking plate. it can.

  In the invention according to claim 5 configured as described above, since the change in the diameter of the grindstone during machining does not affect the appropriate minute gap between the grinding surface and the buoyancy imparting portion, the grindstone correction Sometimes it is possible to adjust the minute gap to an appropriate amount even if the grindstone diameter changes greatly by correcting the movement of the air blocking plate after the correction of the grindstone, and again restricting the movement of the air blocking plate after the grindstone correction. it can.

  In the invention according to claim 6 configured as described above, it is necessary to allow the fluid nozzle to reliably supply the fluid to the grinding point even if the diameter of the grindstone changes. Therefore, by forming the fluid nozzle on the air blocking plate, the fluid nozzle can be moved following the diameter of the grindstone without providing a driving source.

   A grinding apparatus according to a first embodiment of the present invention will be described below with reference to FIGS. A grinding wheel base 11 is slidably mounted on the bed 10 and moved forward and backward in the X-axis direction approaching and separating from the workpiece W by a servo motor 12 via a ball screw mechanism. A grindstone shaft 13 having a grindstone G attached to one end is rotatably supported on the grindstone base 11 and is rotated by an electric motor 29. The grindstone G is configured by adhering a plurality of grindstone chips containing diamond or CBN abrasive grains to the outer peripheral surface of a disc-shaped substrate formed of metal such as iron or aluminum. A table 14 is slidably mounted on the bed 10 and is moved by a servo motor 15 via a ball screw mechanism 16 in the Z-axis direction perpendicular to the X-axis. A spindle stock (not shown) and a tailstock 18 constituting the workpiece support device 17 are mounted on the table 14, and the workpiece W is sandwiched between both centers of the spindle stock and the tailstock 18 and is driven to rotate. .

   A grindstone guard 19 that covers the grindstone G is fixed to the grindstone base 11. The grindstone guard 19 includes a top plate 19a covering the upper surface of the grindstone G and a side plate 19b covering the side surfaces.

   A fluid nozzle 21 of a fluid supply device 20 is attached to the upper surface of the top plate 19a, and coolant is supplied from the fluid nozzle 21 toward a grinding point P where the grindstone G grinds the workpiece W, and this coolant flow is The grinding surface Ga is reached at a reaching point Gd in the vicinity of the grinding point P. In the present embodiment, the coolant means all fluids used for cooling and lubricating the grindstone G and the workpiece W. For example, a liquid such as a lubricating oil, a cooling gas (cold air), and A mist-like fluid in which these liquids and gases are mixed can be used.

  On the ceiling plate 19a of the grindstone guard 19, as shown in FIGS. 2 and 3, a shielding mechanism 30 for blocking the grindstone-associated air layer 27 is attached. The shielding mechanism 30 includes a holding member 31 and an air shielding plate 32, and the holding member 31 has a cylindrical body elongated in the width direction of the outer peripheral grinding surface Ga. The holding member 31 has one end in the longitudinal direction attached to the opening end side of the ceiling 19 a and the other end extending in a direction toward the rotation center of the grindstone G. An air shielding plate 32 is held in the holding member 31 via a slide bearing 33 so as to be slidable in the radial direction toward the rotation axis of the grindstone G. The air shielding plate 32 is a flat plate having a predetermined thickness, and is a push between the ceiling plate 19a and the air shielding plate 32 to press the air shielding plate 32 against the outer peripheral grinding surface Ga of the grindstone G. A spring 34 for applying pressure F1 is interposed. At the end face of the air shielding plate 32 on the grinding surface Ga side of the grindstone G, the outer peripheral grinding surface Ga and both sides of the grindstone G are slightly upstream of the arrival point Gd where the coolant flow reaches the outer circumferential grinding surface Ga. An opening groove 35 surrounding the surfaces Gb and Gc is formed. The groove end portion 35a of the opening groove 35 opposes the outer grinding surface Ga of the grindstone G so as to face the outer grinding surface Ga of the grindstone G in order to block the grinding wheel associated air layer 27 that rotates along with the outer grinding surface Ga of the grindstone G. The groove end portion 35a that extends in the transverse direction and is a buoyancy imparting portion is formed on the groove end surface La parallel to the outer peripheral grinding surface Ga formed by the plate thickness of the air shielding plate 32, and on one side opposite to the rotational direction of the grindstone Ga. The chamfer Lb is formed. Further, both side edges 35b, 35c of the opening groove 35 are opposed to both side faces Gb, Gc of the grindstone G with a slight gap, and extend from the grinding point P to a lower position.

   The groove end portion 35a composed of the groove end surface La and the chamfer Lb uses dynamic pressure generated when the grindstone-associated air layer 27 enters a minute gap formed between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La. Then, it is used to obtain a buoyancy F2 that moves the air shielding plate 32 in the radial direction of the grindstone G, in a direction that widens a minute gap formed between the outer peripheral grinding surface Ga and the groove end surface La.

  Here, the relationship between the pressing force F1 and the buoyancy F2 will be described with reference to FIGS. The minute gap formed between the groove end surface La of the groove end portion 35a and the outer peripheral grinding surface Ga is determined by the position of the air shielding plate 32 where the pressing force F1 = buoyancy F2. As described above, the buoyancy F2 uses dynamic pressure generated when the grinding stone-associated air layer 27 enters the minute gap formed between the outer peripheral grinding surface Ga of the grinding stone G and the groove end surface La. FIG. 4 shows the relationship between the minute gap and the buoyancy F2 generated by the dynamic pressure. As shown in FIG. 4, the buoyancy F2 increases rapidly when the minute gap formed between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La becomes below a predetermined value. Further, the buoyancy F2 is always constant regardless of the diameter of the grindstone G depending on the distance of the minute gap. Therefore, by adjusting the pressing force F1, the gap between the outer peripheral grinding surface Ga and the groove end surface La of the grindstone G is adjusted. It is possible to adjust the size of the minute gap formed on the surface. Further, since the buoyancy F2 does not depend on the diameter of the grindstone G, means for always generating a constant pressing force, for example, the spring 34 in the present embodiment can be used. Further, since the air shielding plate 32 itself has its own weight, the pressing force by the weight of the air shielding plate 32 may be used. Further, as shown in FIG. 5, the buoyancy F2 due to the dynamic pressure is increased by increasing the area of the groove end surface La. Therefore, the area of the groove end surface La, that is, the plate thickness of the air shielding plate 32 is adjusted, and the grindstone The size of the minute gap formed between the outer peripheral grinding surface Ga of G and the groove end surface La can be adjusted. Moreover, the buoyancy F2 by dynamic pressure can also be adjusted by forming the chamfer Lb and adjusting the inclination of the chamfer Lb. In order to block the air layer 27 associated with the grindstone by the air shielding plate 32, the size of the minute gap formed between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La is adjusted to 0.2 mm or less. There is a need to. In the present embodiment, the pressing force F1 is adjusted by the weight of the air shielding plate 32 and the spring 34, and the buoyancy F2 is adjusted by the area of the groove end surface La and the inclination of the chamfer Lb. Since the air layer 27 associated with the grindstone changes depending on the peripheral speed of the grindstone G, the weight of the air shielding plate 32 and the adjustment of the pressing force F1 by the spring 34, the area of the groove end surface La, and the buoyancy F2 due to the inclination of the chamfer Lb. It is necessary to adjust according to the peripheral speed of the grindstone G at the time of grinding.

  1 again, an air jet nozzle 36 is mounted from the ceiling plate 19a at a position upstream of the shielding mechanism 30 in the grinding wheel rotation direction. The air jet nozzle 36 is connected to a pressurized air source such as factory air via an electromagnetically driven on-off valve 37, for example, and the air jet is formed between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La. Injecting toward the gap, buoyancy is imparted to the air shielding plate 32.

  A digital servo control device 40a is connected to the servo motor 12 as shown in FIG. This digital servo device 40a is connected to a CNC device 41 that controls the entire machine, and controls the rotation of the servo motor 12 based on the deviation between the feed command from the CNC device 41 and the position feedback signal of the grinding wheel base 11 from the encoder 12a. The feed speed and movement position of the grinding wheel base 11 are controlled. The servo motor 15 is connected to a digital servo control device 40b, and the digital servo device 40b is connected to a CNC device 41. The digital servo device 40b controls the rotation of the servo motor 15 based on the deviation between the feed command from the CNC device 41 and the position feedback signal of the table 14 from the encoder 15a, and controls the feed speed and moving position of the table 14.

  In addition to the digital servo devices 40 a and 40 b, the CNC device 41 includes a sequence controller (hereinafter referred to as “PLC”) 42 that opens and closes the on-off valve 37 and controls the fluid supply device 20 based on commands from the CNC device 41. An input / output device 43 for inputting / outputting various information is also connected.

  The fluid supply device 20 includes a pump 22, a motor 23, and an inverter circuit 24 that controls the rotation of the motor 23. The inverter circuit 24 is connected to the PLC 42, and controls the rotation of the motor 23 based on the rotation start and rotation stop commands and the rotation speed of the pump 22 that are commanded from the CNC device via the PLC 42. A coolant having a flow rate corresponding to the rotational speed of the pump 22 is supplied.

  The CNC device 41 includes a CPU 44, a ROM 45, and a RAM 46 for storing input data and the like. The ROM 45 stores a grinding program for controlling a grinding cycle as an NC program.

  Next, the operation at the start of grinding of the grinding apparatus configured as described above will be described based on the flowchart of FIG. The flowchart of FIG. 7 shows the operation of the NC program stored in the ROM 45 of the CNC device 41, and is executed when a machining start is instructed from the input / output device 43 to the CNC device 41. At first, when the grindstone G is stopped, the air layer 27 associated with the grindstone is not generated, and the air shielding plate 32 is in contact with the outer peripheral grindstone surface Ga of the grindstone G by the pressing force F1 of the spring 34.

  When the program starts, first, in step 100, the CNC device 41 outputs a command to open the on-off valve 37 via the PLC. When the on-off valve 37 is opened, an air jet is supplied from the pressurized air source 25 to the air jet nozzle through the open on-off valve 37 and injected between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La. Is done. When the air jet is injected between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La, dynamic pressure is generated by the air jet, and the buoyancy F <b> 2 acts on the air shielding plate 32. When the buoyancy F2 acts on the air shielding plate 32, the air shielding plate 32 moves toward the top plate 19a against the pressing force F1 of the spring 34, and a minute gap is formed between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La. Is formed. Then, in step 101, after 1 second has elapsed since opening the on-off valve 37, the process proceeds to step 102, a rotation command is issued to the electric motor 29, and the grindstone G starts rotating. Thus, by separating the air shielding plate 32 from the outer peripheral grinding surface Ga at the start of rotation of the grindstone G, it is possible to prevent the groove end portion 31 from being scraped to the outer peripheral grinding surface Ga.

  When the grindstone G starts to rotate, air is accompanied by the grindstone G around the outer periphery of the outer peripheral grindstone surface Ga as the rotation increases, and the air-associated air layer 27 is gradually generated. Then, with generation | occurrence | production of the grindstone-associated air layer 27, the air shielding plate 32 shields the grindstone-associated air layer 27 before reaching the arrival point Gd. At this time, both the air jet and the air flow of the air associated with the grindstone 27 act between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La. Both the air flow of the air jet and the air layer 27 associated with the grindstone act between the outer peripheral grinding surface Ga and the groove end surface La, and the buoyancy F2 further acts on the air shielding plate 32 to cause the outer peripheral grinding surface Ga of the grindstone G. And a minute gap between the groove end face La is widened. In this state, in step 103, the CNC device 41 detects whether or not the electric motor 29 has rotated at a constant speed. If the electric motor 29 has rotated at a constant speed, the process proceeds to the next step 104, via the PLC 42. A command to close the on-off valve 37 is output, and supply of the air jet is stopped. When this air jet is stopped, only the air flow of the grinding stone associated air layer 27 acts between the outer peripheral grinding surface Ga and the groove end surface La, and the buoyancy F2 is weakened. When the buoyancy F2 is weakened, the air shielding plate 32 is pushed back to the outer peripheral grinding wheel surface side by the action of the pressing force F1 of the spring 34, and the minute gap between the outer peripheral grinding surface Ga and the groove end surface La is 0.2 as originally planned. Stable near mm. As a result, the air shielding plate 32 forms a minute gap of about 0.2 mm between the outer peripheral grinding surface Ga and the groove end surface La by the grinding wheel-associated air layer 27, and moves to the grinding point P side. Layer 27 will be blocked. Then, when the routine proceeds to step 105, a rotation command for the workpiece W is issued, the workpiece W is sandwiched and rotated between both centers of the headstock and the tailstock 18, and the grindstone platform 11 is advanced by the servo motor 12. . In step 106, a coolant supply command is output from the CNC device 41 to the fluid supply device 20 via the PLC 42. When the coolant supply command is output, the fluid supply device 20 supplies the coolant flow from the fluid nozzle 21 toward the reaching point Gd of the grindstone G. At this time, since the grinding wheel-associated air layer 27 does not reach the arrival point Gd by the air shielding plate 32, the coolant flow supplied from the fluid nozzle 21 is in close contact with the outer peripheral grinding surface Ga without being obstructed by the grinding wheel-associated air layer 27. Thus, it is reliably supplied to the grinding point P. Thereafter, in step 107, the workpiece W is ground by the grindstone G. Then, when the grinding of the workpiece W in step 107 is completed, the process proceeds to step 108. In step 108, the CNC device 41 outputs a command to open the on-off valve 37 via the PLC 42. When the on-off valve 37 is opened, an air jet is supplied from the pressurized air source to the air jet nozzle 36 through the open on-off valve 37 and is formed between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La. It is injected toward the minute gap. When the air jet is sprayed toward the minute gap, both the air jet and the air flow of the grinding wheel associated air layer 27 act between the outer peripheral grinding surface Ga of the grinding wheel G and the groove end surface La, and the air jet and the grinding wheel are accompanied. Due to the action of both the air flow in the air layer 27 between the outer peripheral grinding surface Ga and the groove end surface La, the buoyancy F2 further acts on the air shielding plate 32, and the outer grinding surface Ga of the grindstone G and the groove end surface La A minute gap between them will be widened. In this state, when the process proceeds to step 109 and a command to stop the rotation of the electric motor 29 is commanded, the rotation of the grindstone G gradually slows down. As a result, air no longer travels around the grindstone G, and the grindstone-associated air layer 27 disappears. At this time, since the air jet from the jet nozzle 36 acts on the air shielding plate 32, a minute gap between the outer peripheral grinding surface Ga and the groove end surface La is maintained. Thus, by separating the air shielding plate 32 from the outer peripheral grinding surface Ga when the grindstone G stops rotating, the groove end portion 31 can be prevented from being scraped to the outer peripheral grinding surface Ga. In step 110, the CNC device 41 detects whether or not the electric motor 29 has stopped. If the electric motor 29 has stopped, the CNC device 41 proceeds to the next step 111 and outputs a command to close the on-off valve 37 via the PLC 42. Then, the supply of air jet is stopped.

  As described above, the air flow of the grinding wheel-associated air layer 27 acts between the outer peripheral grinding surface Ga of the grindstone G of the air shielding plate 32 and the groove end portion 35a facing the outer peripheral grinding surface Ga, thereby applying dynamic pressure. By generating the buoyancy F2 in the air shielding plate 32 by this dynamic pressure, an appropriate numerical value (0.2 between the outer peripheral grinding surface Ga and the groove end 35a can be obtained with a simple configuration regardless of the diameter of the grindstone G. A minute gap of less than or equal to millimeter) can be formed. In addition, when the rotation of the grindstone G is started and stopped, by supplying an air jet between the outer peripheral grinding surface Ga and the groove end portion 35a, the grindstone G rotates slowly, and the buoyancy F2 sufficient by the grindstone-associated air layer 27 is sufficient. Can not be obtained, the contact between the grindstone G and the air shielding plate 32 can be prevented. As a result, the air shielding plate 32 can be prevented from being scraped in contact with the grindstone G when the grindstone G starts and stops rotating.

  If the air shielding plate 32 is manufactured on the premise that the grindstone G is scraped by the grindstone G when the grindstone G starts and stops rotating, it is not necessary to supply an air jet. In this case, the air shielding plate 32 may be formed of a free-cutting material such as chemical wood.

  Next, a second embodiment will be described. This second embodiment replaces the air jet nozzle 36 in the first embodiment in order to prevent the air shielding plate 32 from being scraped by the grindstone G when the grindstone G starts and stops rotating. When the grindstone G is stopped, a movement restricting device for restricting the movement of the air shielding plate 32 is provided.

  The second embodiment has the same configuration as that of the first embodiment except that a movement restricting device is provided instead of the air jet nozzle 36 and the on-off valve 37. Is omitted.

  The movement restricting device is an electromagnetic solenoid 50 mounted on the side surface of the holding member 31 as shown in FIG. The electromagnetic solenoid 50 includes a plunger 51 that contacts the side surface of the air shielding plate 32, a housing 52, a coil spring 53, and an electromagnet 54. The housing 52 is fixed to the side surface of the holding member 31, and an inner hole 55 is formed in the housing 52 in a direction orthogonal to the moving direction of the air shielding plate 32, and a cylindrical electromagnet 54 is disposed on the outer periphery of the inner hole 55. Has been. A flanger 51 is slidably inserted into the inner hole 55 and restricts the movement of the air shielding plate 32 in the direction of the outer peripheral grinding surface Ga when the plunger 51 comes into contact with the side surface of the air shielding plate 32. A coil spring 53 is inserted into the rear end of the plunger 51 so as to press the plunger 51 against the side surface of the air shielding plate 32. The electromagnet 54 attracts the plunger 51 in a direction in which the plunger 51 is separated from the side surface of the air shielding plate 32 by electromagnetic force. The operation of the grinding apparatus configured as described above will be described. When the grindstone G stops rotating, the plunger 51 is pressed against the side surface of the air shielding plate 32 by the pressing force of the coil spring 53, and the movement of the air shielding plate 32 is restricted. At this time, a minute gap is maintained between the outer peripheral grinding surface Ga of the air shielding plate 32 and the groove end surface La. In this state, when the grindstone G is rotated and the grindstone-associated air layer 27 is generated, the electromagnet 54 is turned on and the movement of the air shielding plate 32 by the plunger 51 is released. As a result, the air flow in the air layer 27 accompanying the grindstone acts between the outer peripheral grinding surface Ga and the groove end surface La, and the air shielding plate 32 is moved by the action of the buoyancy F2 and the pressing force F1, and the outer peripheral grinding is performed. The minute gap between the face Ga and the groove end face La is stabilized in the vicinity of 0.2 mm that was initially planned. Thereafter, grinding is performed. Further, when the rotation stop of the grindstone G is instructed, the electromagnet 54 is turned off to restrict the movement of the air shielding plate 32 by the plunger 51. As a result, even if the rotation of the grindstone G is stopped, the minute gap between the outer peripheral grinding surface Ga and the groove end surface La is maintained, and the air shielding plate 32 comes into contact with the grindstone G to start and stop the rotation of the grindstone G. It will not be shaved. In addition, the change of the diameter of the grindstone G during the grinding process does not affect an appropriate minute gap between the outer peripheral grinding surface Ga and the groove end surface La. Therefore, if the restriction of the movement of the air shielding plate 32 is canceled at the same time when the rotation of the grindstone G becomes a constant speed rotation, and the movement of the air shielding plate 32 is restricted again, the outer peripheral grinding surface Ga and the groove end surface The minute gap between La is adjusted to an appropriate amount.

  Furthermore, the diameter of the grindstone G is greatly reduced when the outer peripheral grinding surface Ga of the grindstone G is corrected. Therefore, if the restriction of the movement of the air shielding plate 32 is canceled when the outer peripheral grinding surface Ga having a large change in the diameter of the grindstone G is corrected, and the movement of the air shielding plate 32 is restricted after the completion of the correction of the outer peripheral grinding surface Ga, the outer peripheral grinding surface. The minute gap between Ga and the groove end face La is adjusted to an appropriate amount.

  Next, a third embodiment will be described. The third embodiment is characterized in that the air shielding plate 32 is supported to swing while the moving direction of the air shielding plate 32 in the first embodiment is a straight line. Specifically, as shown in FIG. 9, the air shielding plate 32 is formed in an approximately L shape, and the vicinity of the center of the air shielding plate 32 can pivot on a support shaft 60 extending in parallel with the outer peripheral grinding surface Ga. It is supported by. The tip of the air shielding plate 32 on the outer peripheral grinding surface Ga side surrounds the grinding surface Ga and both side surfaces Gb, Gc of the grinding wheel G at a position slightly upstream of the point where the coolant flow reaches the grinding surface. An opening groove 35 is formed. The groove end portion 35a of the opening groove 35 opposes the outer grinding surface Ga of the grindstone G so as to face the outer grinding surface Ga of the grindstone G in order to block the grinding wheel associated air layer 27 that rotates along with the outer grinding surface Ga of the grindstone G. The groove end 35a extends in a transverse direction, and has a chamfer Lb formed on a groove end surface La parallel to the outer peripheral grinding surface Ga formed by the thickness of the air shielding plate 32 and on one side opposite to the rotational direction of the grindstone Ga. Consists of The groove end portion 35a composed of the groove end surface La and the chamfer Lb uses dynamic pressure generated when the grindstone-associated air layer 27 enters a minute gap formed between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La. Then, it is used to obtain a buoyancy F2 that moves the air shielding plate 32 in the radial direction of the grindstone G, in a direction that widens a minute gap formed between the outer peripheral grinding surface Ga and the groove end surface La. One end of a spring 61 is fixed to the rear end of the air shielding plate 32 opposite to the side where the opening groove 35 is formed. The other end of the spring 61 is fixed to a fixed plate 61 attached to the side plate 19 b of the grindstone guard 19, and the air shielding plate 32 moves the air shielding plate 32 to the outer peripheral grinding surface Ga of the grindstone G by the pressing force F <b> 1 of the spring 61. A turning force in a direction to be pressed, that is, a clockwise rotation in FIG. 9 is applied.

   The operation of the grinding apparatus configured as described above will be described. When the grindstone-associated air layer 27 is generated by the rotation of the grindstone G, dynamic pressure is generated between the outer peripheral grinding surface Ga and the groove end surface La, and the buoyancy F2 acts on the air shielding plate. With this buoyancy F2, the air shielding plate 32 is turned around the support shaft against the pressing force F1 of the spring 61 (counterclockwise in FIG. 9), and stopped at a position where the pressing force F1 and the buoyancy F2 are balanced. A minute gap (0.2 mm or less) is formed between the grinding surface Ga and the groove end surface La. At this time, the air layer 27 associated with the grindstone does not reach the reaching point Gd by the air shielding plate 32. For this reason, the coolant flow supplied from the fluid nozzle 21 is reliably supplied to the grinding point P in close contact with the outer peripheral grinding surface Ga without being obstructed by the air layer 27 associated with the grindstone.

   At the start and stop of rotation of the grindstone G, the air jet is blown between the outer peripheral grinding surface Ga and the groove end surface La of the grindstone G by using the air jet nozzle 36 and the on-off valve 37 in the first embodiment. Thus, a dynamic pressure may be generated between the outer peripheral grinding surface Ga and the groove end surface La, and the buoyancy F2 may be applied to the air shielding plate 32. Thus, if the air shielding plate 32 is swiveled around the support shaft 60, the movable resistance for moving the air shielding plate 32 can be reduced.

   Next, a fourth embodiment will be described. In the fourth embodiment, the fluid nozzle 21 is moved using the movement of the air shielding plate 32 so that the coolant can be reliably supplied to the grinding point P even if the diameter of the grindstone G changes. Features.

   A specific configuration is shown in FIG. In FIG. 10, the fluid nozzle 21 of the fluid supply device 20 is attached to the upper surface of the top plate 19 a of the grindstone guard 19. The fluid nozzle 21 is attached to the upper surface of the top plate 19a so as to be turnable at the turning center O, and the fluid nozzle 21 hangs down from the top plate 19a toward the grinding point P of the grindstone G and the workpiece W. It is configured to move. A plate-like air shielding plate 32 extending in the direction of the outer peripheral grinding surface Ga of the grindstone G is formed in the middle of the fluid nozzle 21. The air shielding plate 32 is formed with an opening groove 35 that surrounds the grinding surface Ga and both side surfaces Gb, Gc of the grinding wheel G at a position slightly upstream of the arrival point Gd where the coolant flow reaches the grinding surface Ga. Has been. The groove end portion 35a of the opening groove 35 opposes the outer grinding surface Ga of the grindstone G so as to face the outer grinding surface Ga of the grindstone G in order to block the grinding wheel associated air layer 27 that rotates along with the outer grinding surface Ga of the grindstone G. The groove end 35a extends in a transverse direction, and has a chamfer Lb formed on a groove end surface La parallel to the outer peripheral grinding surface Ga formed by the thickness of the air shielding plate 32 and on one side opposite to the rotational direction of the grindstone Ga. Consists of The groove end portion 35a composed of the groove end surface La and the chamfer Lb uses dynamic pressure generated when the grindstone-associated air layer 27 enters a minute gap formed between the outer peripheral grinding surface Ga of the grindstone G and the groove end surface La. Then, it is used to obtain a buoyancy F2 that moves the air shielding plate 32 in the radial direction of the grindstone G, in a direction that widens a minute gap formed between the outer peripheral grinding surface Ga and the groove end surface La. One end of a spring 65 that applies a force (compression force) in a direction in which the fluid nozzle 21 is brought into contact with the outer peripheral grinding surface Ga of the grindstone G is connected to the proximal end of the fluid nozzle 21 near the turning center. The other end of the spring 65 is fixed to the grindstone guard 19, and the force in the direction in which the fluid nozzle 21 comes into contact with the outer peripheral grinding surface Ga of the grindstone G is applied to the fluid nozzle 21 by the compression force of the spring 65. The air shielding plate 32 is pressed against the outer peripheral grinding surface Ga of the grindstone G by the compression force of the spring 65. In other words, the pressing force F <b> 1 pressed against the outer peripheral grinding surface Ga acts on the air shielding plate 32 by the compression force of the spring 65.

   The operation of the grinding apparatus configured as described above will be described. When the grindstone-associated air layer 27 is generated by the rotation of the grindstone G, dynamic pressure is generated between the outer peripheral grinding surface Ga and the groove end surface La, and the buoyancy F2 is applied to the air shielding plate 32. This buoyancy F2 turns the fluid nozzle 21 around the turning center O (counterclockwise in FIG. 10) against the pressing force F1 applied to the air shielding plate 32 acting by the spring 65, and the pressing force F1 and the buoyancy F2 The air shielding plate 32 is stopped at a position where the two are balanced. Then, a minute gap (0.2 mm or less) is formed between the outer peripheral grinding surface Ga and the groove end surface La. At this time, the coolant is supplied from the tip of the fluid nozzle 21 toward the grinding point P where the grindstone G grinds the workpiece W, and this coolant flow reaches the outer peripheral grinding surface Ga at the arrival point Gd near the grinding point P. To do. Then, since the air layer 27 associated with the grindstone is blocked by the air shielding plate and does not reach the reaching point Gd, the coolant flow supplied from the fluid nozzle 21 is in close contact with the outer peripheral grinding surface Ga without being obstructed by the air layer 27 associated with the grindstone. Thus, it is reliably supplied to the grinding point P.

   Further, when the diameter changes during the rotation of the grindstone G, the minute gap widens and the buoyancy F2 becomes smaller, and the air shielding plate 32 maintains the minute gap so as to balance the pressing force F1 and the buoyancy F2. It moves to the direction pressed by the outer periphery grinding surface Ga by the effect | action of 65. FIG. At this time, since the tip of the fluid nozzle 21 similarly turns in the center direction of the grindstone G, the coolant flow is applied to the outer peripheral grinding surface Ga at the arrival point Gd in the vicinity of the grinding point P.

   As described above, the fluid nozzle 21 moves following the movement of the air shielding plate 32, so that the fluid nozzle can be moved following the diameter of the grindstone G without providing a drive source. it can. Therefore, the fluid nozzle 21 can reliably supply the coolant to the grinding point P regardless of the diameter of the grindstone G.

The side view which shows the grinding device which concerns on this invention. The figure which shows the principal part of the air shielding board which concerns on 1st Embodiment. The figure which shows the principal part of the air shielding board which concerns on 1st Embodiment. The graph which shows the relationship between the clearance gap formed between an air shielding board and a grindstone, and buoyancy. The graph which shows the area of the buoyancy provision part formed in the air shielding board, and the relationship of buoyancy. FIG. 2 is a block diagram of a control device according to the first embodiment. 3 is a flowchart for explaining the operation of the grinding apparatus according to the first embodiment. The figure which shows the structure of 2nd Embodiment. The figure which shows the structure of 3rd Embodiment. The figure which shows the structure of 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Bed, 11 ... Whetstone stand, 12, 15 ... Servo motor, 14 ... Table, 17 ... Work support device, 19 ... Whetstone guard, 20 ... Fluid supply device, 21 ... Fluid nozzle, 27 ... Whetstone-associated air layer, 29 DESCRIPTION OF SYMBOLS ... Electric motor, 30 ... Shielding mechanism, 31 ... Holding member, 32 ... Air shielding plate, 34 ... Spring, 35 ... Opening groove, 35a ... Groove end, 36 ... Air jet nozzle, 37 ... Open / close valve, 40a, 40b ... Digital Servo controller, 41 ... CNC device, 42 ... PLC device, 43 ... obtained output device, 50 ... electromagnetic solenoid, 60 ... support shaft, La ... groove end face, Lb ... chamfer, G ... grinding wheel, Ga ... peripheral grinding surface, Gd ... reaching point, P ... grinding point, W ... workpiece.

Claims (6)

A grindstone is rotatably supported on a grindstone table, a workpiece support device that supports a workpiece to be rotationally driven is moved relative to the grindstone table, and the fluid is fed to the grinding surface of the grindstone by a fluid supply device. In the grinding apparatus for grinding by the grinding surface, an air shielding plate is provided at a position upstream of the grinding point where the grindstone and the workpiece are in contact with each other in the grindstone rotation direction to block the air layer accompanying the grindstone that rotates around the grindstone.
A holding member is provided for holding the air shielding plate in a movable manner in a direction in contact with and away from the grinding surface of the grindstone,
Contact urging means for urging the air shielding plate in a direction approaching the grinding surface is provided,
A buoyancy is imparted to the air shield plate by the air flow in the air layer associated with the grindstone to form a minute gap between the air shield plate and the grindstone surface against the bias force of the contact biasing means. A grinding apparatus, wherein an imparting portion is provided at a portion of the air shielding plate facing the grinding surface of the grindstone. In claim 1,
The holding member is supported so that the air shielding plate can pivot about a support shaft formed in parallel with the grinding surface,
The contact biasing means biases the air shielding plate with a rotational force that causes the buoyancy imparting portion to approach the grinding surface of the grindstone against the flow of the grindstone-associated air layer around the support shaft. A grinding device characterized by the above. In claim 1 or 2,
A fluid jet spraying device for blowing a fluid jet toward the air shielding plate is provided slightly upstream from the position where the buoyancy imparting portion of the air shielding plate faces the grinding surface of the grinding wheel, and the grinding wheel rotates. A grinding apparatus, comprising: a fluid jet ejection control unit that sprays a fluid jet from the fluid jet ejection device toward the air shielding plate when starting and stopping rotation. In claim 1 or 2,
A movement restricting device for restricting movement of the air shielding plate in a direction contacting and separating from the grinding surface of the grindstone;
A restriction control device is provided for controlling the movement restricting device so as to restrict the movement of the air shielding plate while stopping the rotation of the grindstone and permit the movement of the air shielding plate at least during the rotation of the grindstone. A grinding apparatus characterized by that. In claim 1 or 2,
A movement restricting device for restricting movement of the air shielding plate in a direction contacting and separating from the grinding surface of the grindstone;
A grinding apparatus, comprising: a restriction control device that operates the movement restricting device only to correct the grinding surface of the grindstone and allows the air shielding plate to move. In any one of claims 1 to 5,
A grinding apparatus, wherein a fluid nozzle of the fluid supply device is formed integrally with the air shielding plate.

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