JP2011156606A - Grinding device and grinding method for brake disc rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and power-saving grinding device for a brake disc rotor that sufficiently reduces surface wobble at low cost, and a grinding method. <P>SOLUTION: The grinding device 10 includes an upper grinding wheel 16, a lower grinding wheel 18, a table driving motor 48, a support member 54, and a work driving motor 56 giving a rotational driving force to the support member 54. The brake disc rotor 58 is supported by the support member 54. The table driving motor 48 moves the support member 54 so that a ground portion of the brake disc rotor 58 is brought into contact with the upper grinding wheel 16 and the lower grinding wheel 18 at its outer peripheral surface, and then enters between the upper grinding wheel 16 and the lower grinding wheel 18. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a brake disc rotor grinding apparatus and grinding method, and more particularly to a brake disc rotor grinding apparatus and grinding method for a disc brake used as a braking device for an automobile.

  Conventionally, a disc brake has been used as a device for braking a rotating shaft such as an automobile axle. This disc brake brakes the brake disc rotor by sandwiching both sides of a brake disc rotor fixed to the rotating shaft and rotating with the rotation of the rotating shaft with a brake pad operated by a hydraulic cylinder or the like. It is configured to brake the rotation.

  When the brake disc rotor is used by being attached to, for example, an automobile axle, the brake disc rotor is attached to the axle via an attachment member. Specifically, as shown in FIG. 18, first, the brake disc rotor 1 is fixed to the hub 3 by bolts 2. The hub 3 is fixed to the end portion of the axle 5 with the bearing 4 attached to the outer periphery of the hub 3. An inner ring 4a of the bearing 4 is attached to the hub 3, and an outer ring 4b disposed coaxially with the inner ring 4a is attached to a frame 6 of the automobile.

  Accordingly, the hub 3 can slide with respect to the frame 6 of the automobile, and when the axle 5 rotates, the hub 3 and the brake disc rotor 1 rotate with reference to the bearing 4.

  Further, as shown in FIG. 19, a recent automobile disc brake includes a structure in which a bearing 7 having an inner ring 7a is assembled to a bearing case 7b, and the bearing case 7b is attached to a frame 6a. In this disc brake, the bearing case 7 b serves as an outer ring of the bearing 7.

  In this way, the disc brake rotates when the brake disc rotor 1 rotates with reference to the bearings 4 and 7 as the axle 5 rotates, and the rotating brake disc rotor 1 is sandwiched from both sides by disc pads (not shown). The axle 5 is braked.

  Therefore, if a rotational runout occurs in the brake disc rotor 1 during rotation, the disc pad cannot successfully sandwich the brake disc rotor 1 and the braking force is reduced or abnormal noise is generated. The rotor 1 is required to be processed with high accuracy. Specifically, it is necessary to reduce the surface runout of the brake disc rotor 1. Therefore, conventionally, in order to reduce the runout of the brake disc rotor 1, both surfaces of the brake disc rotor 1 are ground by an in-feed type grinding device (for example, see Patent Documents 1 to 3).

  FIG. 20 is a diagram for explaining an example of a conventional processing method of a brake disk rotor using an infeed type grinding apparatus. As shown in FIG. 20 (a), in the conventional processing method, the brake disc rotor 1 is supported by the rotating support member 8a and clamped by the clamper 8b, and between the upper grindstone 9a and the lower grindstone 9b. Inserted into. Thereafter, as shown in FIG. 20B, the upper grindstone 9a and the lower grindstone 9b come into contact with the brake disc rotor 1 so as to sandwich the brake disc rotor 1, and both surfaces of the brake disc rotor 1 are ground. Thereby, the magnitude | size of the surface runout of the brake disc rotor 1 is reduced to about 1/2 to 1/3 with respect to the magnitude of the face runout before grinding.

JP 2002-263993 A JP 2004-243488 A Japanese Utility Model Publication No. 49-3180

  Incidentally, in recent years, the demand for the brake disc rotor 1 having a surface runout of 10 μm or less has increased. However, in order to reduce the surface runout of the brake disc rotor 1 to 10 μm or less by the above-described processing method, it is necessary to suppress the surface runout of the brake disc rotor 1 before grinding to about 20 to 30 μm in advance. In this case, high-precision machining is required in the pre-grinding process (turning). For this purpose, it is necessary to improve the function of the lathe (lathe), and it is necessary to frequently replace the blade of the lathe to maintain high-precision turning. Thereby, the manufacturing cost of the brake disc rotor 1 is greatly increased.

  Further, in the above-described infeed type grinding apparatus, the brake disc rotor 1 is ground so that both surfaces of the brake disc rotor 1 are sandwiched between the upper grindstone 9a and the lower grindstone 9b. Therefore, the upper grindstone 9a, the lower grindstone 9b and the brake disc rotor 1 are ground. The contact resistance with is increased. In this case, since a large driving force is required to rotate the upper grindstone 9a and the lower grindstone 9b, a large driving device must be used. This makes it difficult to make the grinding device compact, and increases the power consumption of the grinding device.

  Therefore, a main object of the present invention is to provide a compact and power-saving brake disc rotor grinding apparatus and grinding method that can sufficiently reduce surface runout at low cost.

  In order to achieve the above object, the brake disk rotor grinding apparatus according to claim 1 is a brake disk rotor grinding apparatus having a portion to be ground to be ground, and a support portion for supporting the brake disk rotor. Driving means for applying a rotational driving force to the support portion to rotate the brake disc rotor, an upper grindstone disposed and rotated at the first grinding position, and a second grinding position below the first grinding position. And a rotating lower whetstone, and a first moving means for moving the support portion so that the portion to be ground comes into contact with the upper whetstone and the lower whetstone from the outer peripheral surface and then enters between the upper whetstone and the lower whetstone. It is characterized by providing.

  A grinding apparatus for a brake disk rotor according to a second aspect is the grinding apparatus according to the first aspect, wherein a second moving means for advancing and retracting the upper grindstone with respect to the upper surface of the portion to be ground and a lower grindstone for the portion to be ground are provided. A third moving means for moving back and forth with respect to the lower surface; a detecting means for detecting a first contact position between the upper grindstone and the upper surface; and a second contact position between the lower grindstone and the lower surface; and a second moving means and a third moving means. Control means for controlling, the drive means includes an electric motor, the detection means detects the first contact position and the second contact position based on the current value of the electric motor, and the control means is a portion to be ground. By controlling the second moving means and the third moving means before grinding, the upper grindstone is brought into contact with the upper surface and the lower grindstone is brought into contact with the lower surface, and the first contact position and the second contact detected by the detecting means Based on location And calculating a grinding position and a second grinding position.

  The grinding apparatus for a brake disc rotor according to claim 3 is the grinding apparatus according to claim 2, wherein the control means calculates the first grinding position and the second grinding position, and then the second moving means and the third movement. By controlling the means, the upper grindstone and the lower grindstone are moved to the first grinding position and the second grinding position, and by controlling the first moving means, the portion to be ground is moved from the outer peripheral surface to the upper grindstone and the first grinding position. It contacts the lower grindstone at the 2 grinding position, and then the support portion is moved so as to enter between the upper grindstone and the lower grindstone.

  According to a fourth aspect of the present invention, there is provided the grinding device for a brake disk rotor according to any one of the first to third aspects, wherein the support portion includes a rotating member that is rotated by driving means and a brake disk rotor on the rotating member. A clamper provided on the brake disc rotor to be fixed to the rotor, and a draw bar provided in the rotating member and configured to be able to advance and retreat in the vertical direction and to be locked to the clamper.

  The method for grinding a brake disc rotor according to claim 5, wherein the portion to be ground of the brake disc rotor supported by the support portion is ground with a rotating upper grindstone and a lower grindstone. Applying a rotational driving force to the part to rotate the brake disc rotor, placing the upper grindstone at the first grinding position, placing the lower grindstone at the second grinding position below the first grinding position, The portion to be ground comes into contact with the upper grindstone and the lower grindstone from the outer peripheral surface thereof, and then the support portion is moved so as to enter between the upper grindstone and the lower grindstone.

  In the brake disc rotor grinding apparatus according to the first aspect, the brake disc rotor supported by the support portion is rotationally driven by the driving means. The upper grindstone is disposed at the first grinding position, and the lower grindstone is disposed at the second grinding position below the upper grindstone. In this state, the support portion is moved by the first moving means so that the portion to be ground of the brake disc rotor comes into contact with the upper grindstone and the lower grindstone from the outer peripheral surface and then enters between the upper grindstone and the lower grindstone. Is done. That is, in this grinding apparatus, the portion to be ground of the brake disc rotor is gradually ground from the outer peripheral side to the inner peripheral side by the upper grindstone and the lower grindstone. In this case, it is possible to prevent force from being applied in the thickness direction from the upper grindstone and the lower grindstone to the portion to be ground. As a result, the occurrence of bending stress in the brake disc rotor can be prevented, and the surface runout of the brake disc rotor can be sufficiently reduced. In addition, since the part to be ground is gradually ground from the outer periphery by the upper and lower grinding stones, a large contact resistance is generated between the upper grinding wheel and the part to be ground and between the lower grinding wheel and the part to be ground. Can be prevented. As a result, the driving force required to rotate the upper grindstone and the lower grindstone can be reduced, so that the means for driving the upper grindstone and the lower grindstone (hereinafter referred to as the grindstone driving means) is cheaper. Can be configured. In addition, since a large driving force is not required to rotate the upper grindstone and the lower grindstone, the grindstone driving means can be made small. As a result, the grinding apparatus can be reduced in size and power consumption of the grinding apparatus can be reduced. Further, since the contact resistance between the upper grindstone and the lower grindstone and the brake disc rotor is reduced, the force (clamping force) for fixing the brake disc rotor on the support member can be reduced. Thereby, deformation of the brake disc rotor itself can be sufficiently prevented. The same applies to the method for grinding a brake disk rotor according to claim 5.

  In the brake disk rotor grinding apparatus according to claim 2, the first contact position between the upper grindstone and the upper surface of the portion to be ground and the lower grindstone and the lower surface of the portion to be ground are detected by the detecting means based on the current value of the electric motor. The second contact position can be detected. In this case, since it is not necessary to separately provide a detection means for detecting the first contact position and a detection means for detecting the second contact position, the product cost of the grinding apparatus can be reduced. Further, by detecting the current value of the electric motor by a common detection means, the change in the current value when the upper grindstone and the part to be ground are in contact and the current value when the lower grindstone and the part to be ground are in contact Changes can be detected with the same sensitivity. In this case, the grinding depth of the portion ground by the upper grindstone until the first contact position is detected on the upper surface of the portion to be ground, and the lower grindstone until the second contact position is detected on the lower surface of the portion to be ground. It is possible to prevent a difference from occurring in the grinding depth of the portion to be ground. Thereby, it can prevent that the intermediate position of a 1st contact position and a 2nd contact position shift | deviates largely from the center position in the thickness direction of a to-be-ground part. Therefore, an intermediate position between the first grinding position calculated based on the first contact position and the second grinding position calculated based on the second contact position is greatly deviated from the center position in the thickness direction of the portion to be ground. Can be prevented. That is, the center position in the thickness direction of the portion to be ground after grinding can be easily brought close to an ideal position (designed position). As a result, the dimensional accuracy of the brake disc rotor can be improved. In general, since the capacity of the electric motor for driving the brake disc rotor is small, the current value of the electric motor changes rapidly even when the upper whetstone or the lower whetstone and the brake disc rotor are in slight contact. Therefore, the first contact position and the second contact position can be detected accurately and quickly by detecting the current value of the electric motor for driving the brake disc rotor.

  Note that the surface runout of the upper surface of the portion to be ground before grinding may be measured in advance, and a position lower than the first contact position by the surface runout may be calculated as the first grinding position. In this case, the runout of the upper surface of the part to be ground can be reliably reduced. Similarly, the surface runout of the lower surface of the part to be ground before grinding may be measured in advance, and a position higher by the surface runout than the second contact position may be calculated as the second contact position. In this case, the runout of the lower surface of the part to be ground can be reliably reduced.

  In the brake disk rotor grinding apparatus according to claim 3, the control means controls the second moving means for moving the upper grindstone to the first grinding position, and the second means for moving the lower grindstone to the second grinding position. The control of the 3 movement means and the control of the 1st movement means for performing grinding of a part to be ground are performed. That is, in this grinding apparatus, grinding of the portion to be ground is automatically executed according to the calculated first grinding position and second grinding position. In this case, even when processing a plurality of brake disc rotors continuously, it is not necessary for the operator to set the first grinding position and the second grinding position for each brake disc rotor and execute the grinding process. Will improve.

  In the brake disk rotor grinding apparatus according to the fourth aspect, the draw bar can be locked to the clamper, and the clamper can be pulled downward by the draw bar. As a result, the brake disc rotor is pushed downward by the clamper, and the brake disc rotor is fixed on the rotating member. In this case, it is not necessary to provide a device for fixing the brake disc rotor on the rotating member on the clamper. Thereby, the space above the clamper can be used as a space for performing work, so that work efficiency is improved. Moreover, since the configuration of the grinding apparatus can be simplified, the manufacturing cost of the grinding apparatus can be reduced.

  According to the present invention, it is possible to obtain a compact and power-saving brake disc rotor grinding apparatus and grinding method that can sufficiently reduce surface runout at low cost.

(A) is a top view which shows the grinding device of the brake disc rotor which concerns on embodiment of this invention, (b) is a side view. It is an enlarged view which shows an upper grindstone and a lower grindstone. It is a figure which shows the state by which the brake disc rotor was fixed on the support member. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is a figure which shows the state which rotated the draw bar 90 degree | times from the state of FIG. It is a block diagram which shows the control system of the grinding device which concerns on embodiment of this invention. It is a flowchart which shows the control operation of a calculating part. It is a figure which shows operation | movement of the upper grindstone, the lower grindstone, and a brake disc rotor before grinding start. It is a figure which shows operation | movement of the upper grindstone, the lower grindstone, and a brake disc rotor at the time of grinding. It is a figure which shows the state of the upper grindstone, the lower grindstone, and a brake disc rotor just before the grinding start. It is a figure which shows the state of the surface runout of the brake disc rotor before grinding. It is a figure which shows the relationship between the surface runout of the upper surface of a to-be-ground part, and the surface runout of a lower surface before grinding. It is a figure which shows a mode at the time of grinding a brake disc rotor using the conventional infeed type grinding apparatus. It is a figure which shows the mode at the time of grinding a brake disc rotor using the grinding device which concerns on embodiment of this invention. (A) is a graph which shows the change of the electric current value of the grindstone drive motor in a comparative example, (b) is a graph which shows the change of the electric current value of the grindstone drive motor in an Example. It is a top view which shows the grinding device of the brake disc rotor which concerns on other embodiment of this invention. It is a top view which shows the grinding device of the brake disc rotor which concerns on further another embodiment of this invention. It is sectional drawing which shows the use condition in which the brake disc rotor was attached to the axle. It is sectional drawing which shows another use condition. It is sectional drawing which shows the prior art, (a) shows the state before a grinding process, (b) shows the state at the time of a grinding process.

  A brake disk rotor grinding apparatus according to an embodiment of the present invention will be described below with reference to the drawings. Referring to FIG. 1, a brake disc rotor grinding apparatus 10 according to an embodiment of the present invention is a vertical double-headed surface grinding machine, and includes a column 12 having a U-shape in side view. In the recess 14 of the column 12, an upper grindstone 16 and a lower grindstone 18 that grind a brake disk rotor 58 (described later) are disposed coaxially and oppositely. As shown in FIG. 2, the upper grindstone 16 includes a disk-shaped substrate 16a and a plurality (18 in this embodiment) of grindstone segments 16b provided at equal intervals on the outer peripheral surface of the substrate 16a. The lower grindstone 18 includes a disc-shaped substrate 18a and a plurality (18 in this embodiment) of grindstone segments 18b provided at equal intervals on the outer peripheral surface of the substrate 18a. As a material of the grindstone segment 16b and the grindstone segment 18b, for example, CBN (cubic boron nitride) abrasive grains or diamond abrasive grains can be used.

  As shown in FIG. 1, the upper grindstone 16 and the lower grindstone 18 are rotatably supported by grindstone shafts 20 and 22, respectively. The grindstone shafts 20 and 22 are linked to grindstone drive motors 28 and 30 via belts 24 and 26, respectively. Accordingly, the rotational driving force of the grindstone driving motors 28 and 30 is transmitted to the grindstone shafts 20 and 22 via the belts 24 and 26, whereby the upper grindstone 16 and the lower grindstone 18 are rotationally driven. The grindstone shafts 20 and 22 are provided with grindstone cutting devices 32 and 34, respectively. The grindstone cutting devices 32 and 34 include, for example, electric motors. The grindstone shafts 20 and 22 advance and retreat in the axial direction based on the driving force of the grindstone cutting devices 32 and 34. As a result, the upper grindstone 16 and the lower grindstone 18 move forward and backward with respect to the portion 58b (see FIG. 3 described later) of the brake disc rotor 58.

  A base 36 is provided at a position adjacent to the column 12, and an adjustment plate 38 is provided on the base 36. The adjustment plate 38 is attached to the base 36 via the three connecting members 40. The connecting member 40 includes an adjustment screw 40a and a lock bolt 40b. The adjustment screw 40a has a substantially cylindrical shape, and has a flange portion 40c at the upper end thereof. The adjustment screw 40 a is screwed to the adjustment plate 38 on the base 36. The fixing bolt 40b is inserted into the adjustment screw 40a and screwed to the base 36. A washer (not shown) is provided between the flange portion 40c of the adjustment screw 40a and the head of the lock bolt 40b, and the adjustment screw 40a is pushed downward by the lock bolt 40b via the washer. Thereby, the movement in the up-down direction of the adjusting screw 40a is restricted.

  The adjustment screw 40a is provided so as to be rotatable with respect to the lock bolt 40b. By rotating the adjustment screw 40a, a portion of the adjustment plate 38 that is screwed to the adjustment screw 40a can be moved up and down. . Therefore, the horizontal adjustment of the adjustment plate 38 can be performed by selectively rotating the three adjustment screws 40a.

  A pair of rails 42 are provided in parallel on the adjustment plate 38, and a slide table 44 is provided on the pair of rails 42. The slide table 44 has a roller 46 that rolls on the rail 42, and is movable along the rail 42 in the arrow X direction. A table drive motor 48 is fixed on the adjustment plate 38. One end of a rod-shaped moving screw 50 is fixed to a rotating shaft (not shown) of the table drive motor 48. The other end of the moving screw 50 is screwed to the slide table 44. The moving screw 50 is rotated by the rotational driving force of the table driving motor 48, and the slide table 44 is moved in the arrow X direction.

  Referring to FIG. 1B, a holding member 52 having a bearing 52a is provided on the slide table 44, and a cylindrical rotating shaft 54a (see FIG. 3) is provided on the holding member 52. A support member 54 is provided. The rotating shaft 54a is rotatably held by a bearing 52a. An electric work drive motor 56 is connected to the rotation shaft 54 a, and the rotation shaft 54 a (support member 54) is rotated by the rotation drive force of the work drive motor 56. Although not shown in FIG. 1 in order to avoid complexity of the drawing, the work drive motor 56 includes a current detection unit 86 that detects the value of the current flowing through the work drive motor 56 (see FIG. 6 described later). Is provided. As the current detection unit 86, various current sensors can be used.

  The brake disc rotor 58 is fixed on the support member 54 using a clamper 60. 3 is a partial cross-sectional view showing the support member 54, the brake disc rotor 58, and the clamper 60, and FIG. 4 is a cross-sectional view taken along line AA of FIG. In FIG. 1, in order to avoid the complexity of the drawing, the clamp jig 62, the draw member 64, the draw bar 66, the hydraulic cylinder 68 and the hydraulic cylinder 74 shown in FIGS. 3 and 4 are not shown.

  As shown in FIG. 3, the brake disc rotor 58 is supported by the support member 54 via a hollow disc-shaped clamp jig 62. On the clamp jig 62, a hollow disc-shaped inlay member 64 having an outer diameter smaller than that of the clamp jig 62 is provided. The axes of the support member 54, the clamp jig 62, and the inlay member 64 are substantially coincident. The inlay member 64 is inserted through the hole 58 a at the center of the brake disc rotor 58. As a result, the axis of the brake disc rotor 58 and the axis of the support member 54 substantially coincide. In addition, the thickness of the outer peripheral part 58b of the brake disc rotor 58 is larger than the other parts. In the brake disk rotor 58, the outer peripheral portion 58b is a portion to be ground by the upper grindstone 16 (see FIG. 2) and the lower grindstone 18 (see FIG. 2). Hereinafter, the outer peripheral portion 58b of the brake disc rotor 58 is referred to as a portion to be ground 58b.

  A draw bar 66 and a hydraulic cylinder 68 are provided in the support member 54. The draw bar 66 includes a shaft portion 66a and a locking portion 66b provided at the upper end of the shaft portion 66a, and is provided so as to be rotatable and movable back and forth in the vertical direction (axial direction). The shaft portion 66 a is inserted through the rotation shaft 54 a of the support member 54. A gear groove (pinion gear) 70 is provided in the shaft portion 66a. Referring also to FIG. 4, a rack gear 72 is attached to the hydraulic cylinder 68. The rack gear 72 is provided so as to extend in a direction perpendicular to the shaft portion 66 a and advances and retreats based on the driving force of the hydraulic cylinder 68. The rack gear 72 meshes with a gear groove 70 (see FIG. 3) of the shaft portion 66a, and the draw bar 66 rotates around the shaft as the rack gear 72 advances and retreats. Referring to FIG. 4, locking portion 66b has a substantially rectangular shape with a short side gently curved in plan view. Referring to FIG. 3, a hydraulic cylinder 74 is attached to the lower end of the shaft portion 66a. The shaft portion 66a advances and retreats in the vertical direction (axial direction) based on the driving force of the hydraulic cylinder 74. The hydraulic cylinders 68 and 74 are connected to a controller (not shown), for example, and an operator can operate the hydraulic cylinders 68 and 74 by operating the controller.

  The clamper 60 has substantially cylindrical internal spaces 76 and 78. The internal space 78 opens on the lower surface side of the clamper 60, and the internal space 76 is formed above the internal space 78 in the clamper 60. Referring to FIGS. 3 and 4, a pair of partition walls 80 are provided between the internal space 76 and the internal space 78. A communication passage 82 that connects the internal space 76 and the internal space 78 is formed between the partition wall 80 and the partition wall 80.

  Referring to FIG. 4, communication path 82 has a substantially rectangular shape with a short side gently curved in plan view. In plan view, the width of the communication path 82 is shorter than the length of the long side of the locking portion 66b. Therefore, when the long side of the locking portion 66b is substantially orthogonal to the long side of the communication path 82 in plan view, the partition 80 prevents the locking portion 66b (drawbar 66) from moving downward. Referring to FIG. 5, in plan view, the length of the long side of communication path 82 is longer than the length of the long side of locking portion 66b, and the width of communication path 82 is larger than the width of locking portion 66b. Therefore, when the long side of the locking portion 66 b is substantially parallel to the long side of the communication path 82 in plan view, the locking portion 66 b can pass through the communication path 82. That is, the draw bar 66 (locking portion 66b) can be moved downward.

  Referring to FIG. 3, when the brake disc rotor 58 is fixed on the support member 54 (clamp jig 62), the operator first clamps so that the spigot member 64 is inserted into the hole 58a. A brake disc rotor 58 is placed on the jig 62. Next, the draw bar 66 is raised by operating the hydraulic cylinder 74. Specifically, the draw bar 66 is raised so that the locking part 66b is positioned above the position shown in FIG. 3 (position where the locking part 66b and the partition wall 80 are in contact). Next, referring to FIG. 5, the clamper 60 is placed on the brake disc rotor 58 so that the locking portion 66 b enters the internal space 76 through the communication path 82. Next, referring to FIG. 4, by operating the hydraulic cylinder 68, the draw bar 66 is rotated so that the long side of the locking portion 66 b is substantially orthogonal to the long side of the communication path 82 in plan view. Thereafter, referring to FIG. 3, the draw bar 66 is lowered by operating the hydraulic cylinder 74, and the lower surface of the locking portion 66 b is locked to the upper surface of the partition wall 80. Accordingly, the clamper 60 is pulled downward by the draw bar 66, and the brake disc rotor 58 is pushed downward by the clamper 60. As a result, the brake disc rotor 58 is fixed on the support member 54 (clamp jig 62).

  On the other hand, when removing the brake disc rotor 58 from the support member 54, first, the operator raises the draw bar 66 by operating the hydraulic cylinder 74. Next, by operating the hydraulic cylinder 68, as shown in FIG. 5, the draw bar 66 is rotated so that the long side of the locking portion 66b is substantially parallel to the long side of the communication path 82 in plan view. . Thereafter, the clamper 60 is lifted upward so that the locking portion 66 b passes through the communication path 82, and the clamper 60 is removed from the brake disc rotor 58. As a result, the brake disc rotor 58 can be removed.

  With reference to FIG. 1A, the column 12 is provided with an ECU (electronic control unit) 84. Referring to FIG. 6, ECU 84 includes a determination unit 88, a storage unit 90, and a calculation unit 92. The determination unit 88 and the calculation unit 92 are realized by a CPU (Central Processing Unit) and a program, for example. The storage unit 90 includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory), stores various data, and functions as a work area for the arithmetic unit 92. A part or all of the determination unit 88 or the calculation unit 92 may be realized by hardware such as an electronic circuit.

  The grindstone drive motors 28 and 30, the grindstone cutting devices 32 and 34, the table drive motor 48, and the work drive motor 56 are electrically connected to the calculation unit 92, and the current detection unit 86 is electrically connected to the determination unit 88 of the ECU 84. It is connected to the. The grindstone drive motors 28 and 30, the grindstone cutting devices 32 and 34, the table drive motor 48, and the work drive motor 56 are controlled by the calculation unit 92. Hereinafter, the control operation of the calculation unit 92 will be described.

  7-10 is a figure for demonstrating the control operation | movement of the calculating part 92. FIG. Referring to FIGS. 1, 6 and 7, when starting grinding of brake disc rotor 58, calculation unit 92 first rotates brake disc rotor 58 by starting work drive motor 56 (see FIG. 1, FIG. 6 and FIG. 7). Step S1). The rotational speed of the brake disc rotor 58 is preferably 100 rpm to 500 rpm, for example.

  Next, referring also to FIG. 8A, the calculation unit 92 starts the table drive motor 48 and enters the portion 58 b to be ground of the brake disc rotor 58 between the upper grindstone 16 and the lower grindstone 18. (Step S2). At this time, the gap G1 (see FIG. 8A) between the upper grindstone 16 and the lower grindstone 18 is larger than the thickness of the portion to be ground 58b.

  Next, referring also to FIG. 8B, the calculation unit 92 activates the grindstone drive motor 28 and the grindstone cutting device 32 to lower the upper grindstone 16 while rotating it (step S <b> 3). Next, the calculating part 92 discriminate | determines whether the contact position of the upper grindstone 16 and the to-be-ground part 58b is detected by the determination part 88 (step S4). Here, in the grinding apparatus 10, the contact position between the upper grindstone 16 and the portion to be ground 58b is utilized by utilizing the increase in the current value of the work drive motor 56 due to the contact resistance between the upper grindstone 16 and the portion to be ground 58b. Is detected. Specifically, first, the current detection unit 86 detects the current value of the work drive motor 56 and provides a signal corresponding to the detected current value to the determination unit 88. Next, the determination unit 88 determines whether or not the current value of the work drive motor 56 exceeds a predetermined first threshold based on the signal given from the current detection unit 86. The first threshold will be described later. When the current value exceeds the first threshold value, the determination unit 88 determines that the upper grindstone 16 and the portion to be ground 58b are in contact, and the position (height) of the upper grindstone 16 at that time. ) To set a flag in a predetermined storage area of the storage unit 90. In this way, the determination unit 88 detects the contact position between the upper grindstone 16 and the portion to be ground 58b. The arithmetic unit 92 determines that the contact position between the upper grindstone 16 and the portion to be ground 58b has been detected when a flag is set in a predetermined storage area of the storage unit 90.

  In step S4, when the contact position between the upper grindstone 16 and the portion to be ground 58b is not detected, the arithmetic unit 92 lowers the upper grindstone 16 until the contact position between the upper grindstone 16 and the portion to be ground 58b is detected. Let

  Referring also to FIG. 8C, when the contact position between the upper grindstone 16 and the portion to be ground 58 b is detected in step S <b> 4, the calculation unit 92 controls the grindstone cutting device 32 to control the upper grindstone 16. Is returned to the original position (step S5).

  Next, referring also to FIG. 10, the calculation unit 92, based on the contact position between the upper grindstone 16 and the portion to be ground 58 b detected in step S <b> 4, the grinding position P <b> 1 of the portion to be ground 58 b by the upper grindstone 16. And the calculated grinding position P1 is stored in the storage unit 90 (step S6). The grinding position P1 is calculated as a position below at least the upper surface 58d of the portion to be ground 58b. A method for calculating the grinding position P1 will be described later.

  Next, referring also to FIG. 8D, the calculation unit 92 activates the grindstone drive motor 30 and the grindstone cutting device 34 to raise the lower grindstone 18 while rotating (step S7). Next, the calculation unit 92 determines whether or not the determination unit 88 has detected the contact position between the lower grindstone 18 and the portion to be ground 58b (step S8). The contact position between the lower grindstone 18 and the portion to be ground 58b is detected by a method similar to the method for detecting the contact position between the upper grindstone 16 and the portion to be ground 58b described above. That is, based on the current value of the work drive motor 56 detected by the current detection unit 86, the contact position between the lower grindstone 18 and the portion to be ground 58b is detected by the determination unit 88. In step S4 described above, the first threshold value is used to detect the contact position between the upper grindstone 16 and the portion to be ground 58b. However, in step S8, the lower grindstone 18 and the portion to be ground 58b The second threshold value is used to detect the contact position. The second threshold will be described later.

  In step S8, when the contact position between the lower grindstone 18 and the portion to be ground 58b is not detected, the calculation unit 92 raises the lower grindstone 18 until the contact position between the lower grindstone 18 and the portion to be ground 58b is detected. Let

  8E, when the contact position between the lower grindstone 18 and the portion to be ground 58b is detected in step S8, the calculation unit 92 controls the grindstone cutting device 34 to control the lower grindstone 18. Is returned to the original position (step S9).

  Next, referring also to FIG. 10, the calculation unit 92, based on the contact position between the lower grindstone 18 and the portion to be ground 58 b detected in step S <b> 8, the grinding position P <b> 2 of the portion 58 b to be ground by the lower grindstone 18. And the calculated grinding position P2 is stored in the storage unit 90 (step S10). The grinding position P2 is calculated as a position at least above the lower surface 58e of the portion to be ground 58b. A method for calculating the grinding position P2 will be described later.

  Next, referring also to FIG. 8 (f), the calculation unit 92 moves the brake disc rotor 58 backward by controlling the table drive motor 48 (step S 11). Specifically, the brake disk rotor 58 is moved backward so that the portion 58b to be ground is positioned outside the space between the upper grindstone 16 and the lower grindstone 18.

  Next, referring also to FIG. 9A and FIG. 10, the calculation unit 92 controls the grindstone cutting devices 32 and 34 to move the grindstone 16 and the lower grindstone 18 to the grinding positions P1 and P2, respectively. (Step S12). At this time, the upper grindstone 16 and the lower grindstone 18 are rotating. Further, a gap G2 (see FIG. 10) between the grinding position P1 and the grinding position P2 is smaller than the thickness of the portion 58b to be ground of the brake disc rotor 58.

  Next, referring also to FIGS. 9 (b) to 9 (d), the calculation unit 92 controls the table drive motor 48 to move the grinding target portion 58 b of the brake disk rotor 58 to the upper grinding stone 16 and the lower grinding stone. 18 (step S13). At this time, the brake disc rotor 58 is rotating. In step S13, as shown in FIG. 9B, the calculation unit 92 first sets the outer peripheral surface 58c of the portion 58b to be ground to the grindstone segment 16b of the upper grindstone 16 (see FIG. 2) and the lower grindstone 18. The brake disk rotor 58 is advanced toward the upper grindstone 16 and the lower grindstone 18 so as to come into contact with the grindstone segment 18b (see FIG. 2). Thereafter, the calculation unit 92 causes the portion to be ground 58b to enter between the upper grindstone 16 and the lower grindstone 18 as shown in FIGS. 9 (c) and 9 (d). Then, the calculation unit 92 advances the brake disc rotor 58 to a position where the grinding of the upper surface 58d and the lower surface 58e of the portion to be ground 58b is completed. The position at which grinding of the portion to be ground 58b is completed (the forward stop position of the brake disc rotor 58) is stored in advance in the storage unit 90.

  Next, referring also to FIG. 9E, the arithmetic unit 92 returns the upper grindstone 16 and the lower grindstone 18 to their original positions by controlling the grindstone cutting devices 32 and 34 (step S14). Finally, referring also to FIG. 9 (f), the calculation unit 92 returns the brake disc rotor 58 to the original position by controlling the table drive motor 48 (step S 15). Thereby, the grinding process of the brake disc rotor 58 by the grinding apparatus 10 is completed. Thereafter, the brake disc rotor 58 after grinding and the other brake disc rotor before grinding are replaced, and the above-described processing from step S1 to step S15 is repeated.

Here, a method of calculating the grinding positions P1 and P2 in the above-described step S6 and step S10 will be described.
11 and 12 are diagrams showing an example of a state of surface runout of the brake disk rotor 58 before grinding. FIG. 11 shows the state of the portion to be ground 58b that passes through the position indicated by the line BB in FIG. 4 when the brake disk rotor 58 is rotated once. FIG. 12 shows the locus (up and down) of the outer edge b1 (see FIG. 11) of the upper surface 58d (see FIG. 11) passing through the position indicated by the line BB in FIG. Change in height in the direction) and the locus (change in height in the vertical direction) of the outer edge b2 (see FIG. 11) of the lower surface 58e (see FIG. 11). In FIGS. 11 and 12, the center position in the thickness direction of the portion to be ground 58b is indicated by a broken line C1.

  Referring to FIGS. 11 and 12, brake disc rotor 58 before grinding has surface runouts S1 and S2 (see FIG. 12) on upper surface 58d (see FIG. 11) and lower surface 58e (see FIG. 11), respectively. The trajectory per cycle of the outer edges b1 and b2 passing through the line BB in FIG. 4 is a substantially sine curve. Referring to FIG. 12, when lowering upper grindstone 16 in step S3 described above, upper grindstone 16 moves to upper surface 58d when it is lowered to position P3 that is the same height as the maximum height of outer edge b1 of upper surface 58d. First contact (outer edge b1). Here, the first threshold value used in step S4 described above is equal to the value of the current flowing through the work drive motor 56 when the upper surface 58d (outer edge b1) is ground by the upper grindstone 16 from the position P3 by the depth d1. Therefore, in step S4 described above, when the grinding depth of the upper surface 58d by the upper grindstone 16 exceeds the depth d1, the current value of the work drive motor 56 exceeds the first threshold value, and the determination unit 88 causes the upper grindstone 16 to be processed. And a contact position between the portion to be ground 58b (upper surface 58d). Therefore, the determination unit 88 detects a position P4 that is lower by a depth d1 than the position P3 in the vertical direction as a contact position between the upper grindstone 16 and the portion to be ground 58b (upper surface 58d). The first threshold is preferably set so that the depth d1 is 20 μm to 30 μm, for example. Thereafter, the calculation unit 92 calculates the grinding position P1 by adding the depth d2 to the depth d1. The depth d2 is stored in advance in the storage unit 90. The depth d2 is set, for example, so that the grinding position P1 is a position below the upper surface 58d of the part to be ground 58b before grinding. For example, the surface runout S1 of the upper surface 58d before grinding may be measured in advance, and the measured runout S1 may be set as the depth d2. That is, a position lower than the contact position P4 by at least the surface shake S1 may be calculated as the grinding position P1. In this case, the runout of the upper surface 58d can be reliably reduced.

  With reference to FIG. 12, when raising the lower grindstone 18 in the above-described step S7, the lower grindstone 18 moves to the lower surface 58e when it rises to a position P5 that is the same height as the minimum height of the outer edge b2 of the lower surface 58e. First contact (outer edge b2). Here, the second threshold value used in step S8 described above is equal to the value of the current that flows to the work drive motor 56 when the lower surface 58e (outer edge b2) is ground by the lower grindstone 18 for a depth d4 from the position P5. Accordingly, in step S8 described above, when the grinding depth of the lower surface 58e by the lower grindstone 18 exceeds the depth d4, the current value of the work drive motor 56 exceeds the second threshold value, and the determination unit 88 causes the lower grindstone 18 to be processed. And a contact position between the portion to be ground 58b (lower surface 58e). Therefore, the determination unit 88 detects a position P6 that is higher by a depth d4 than the position P5 in the vertical direction as a contact position between the lower grindstone 18 and the portion to be ground 58b (lower surface 58e). The second threshold is preferably set such that the depth d4 is 20 μm to 30 μm, for example. Thereafter, the calculation unit 92 calculates the grinding position P2 by adding the depth d5 to the depth d4. The depth d5 is stored in advance in the storage unit 90. The depth d5 is set, for example, so that the grinding position P2 is located above the lower surface 58e of the part 58b to be ground before grinding. For example, the surface runout S2 of the lower surface 58e before grinding may be measured in advance, and the measured runout S2 may be set as the depth d5. That is, a position higher than the contact position P5 by at least the surface shake S2 may be calculated as the grinding position P2. In this case, the runout of the lower surface 58e can be reliably reduced. The first threshold value and the second threshold value are appropriately set according to the state (surface runout) of the portion to be ground 58b before grinding, and are set so that the depth d1 and the depth d4 are equal to each other. Although it is preferable, the depth d1 and the depth d4 may be set to be different values.

  In this embodiment, the support member 54, the clamper 60, the clamp jig 62, and the draw bar 66 are included in the support portion, the grinding position P1 corresponds to the first grinding position, the grinding position P2 corresponds to the second grinding position, The work drive motor 56 corresponds to the drive means, the table drive motor 48 and the moving screw 50 function as the first movement means, the grindstone cutting device 32 corresponds to the second movement means, and the grindstone cutting device 34 is the third. The position P4 corresponds to the first contact position, the position P6 corresponds to the second contact position, the current detection unit 86 and the determination unit 88 function as the detection unit, and the calculation unit 92 serves as the control unit. Correspondingly, the support member 54 and the clamp jig 62 are included in the rotating member.

  Next, the effects of the grinding apparatus 10 will be described while comparing with a conventional in-feed type grinding apparatus. FIG. 13 is a diagram showing a state in which a brake disc rotor is ground using a conventional in-feed type grinding apparatus. FIG. 13 is a view of the brake disc rotor 1, the upper grindstone 9a, and the lower grindstone 9b in the direction of the arrow X1 in FIG. FIG. 13B shows a state where the brake disc rotor 1 is rotated 180 degrees from the state shown in FIG.

  As shown in FIG. 13, in the conventional in-feed type grinding apparatus, the upper grindstone 9a and the lower grindstone 9b are arranged such that the upper surface of the brake disc rotor 1 sandwiches the brake disc rotor 1 from above and below as indicated by arrows Y1 and Y2. And grind the lower surface. Here, the brake disc rotor 1 before grinding has a large runout (for example, about 50 μm). Therefore, at the start of grinding, the contact position of the upper surface of the brake disc rotor 1 and the upper grindstone 9a and the contact position of the lower surface of the brake disc rotor 1 and the lower grindstone 9b are determined in the circumferential direction of the brake disc rotor 1 (brake disc rotor 1 (When viewed from the axial direction), they are far apart from each other. In this case, the force F1 (F2) applied in the thickness direction from the upper grindstone 9a to the brake disc rotor 1 and the force F3 (F4) applied in the thickness direction from the lower grindstone 9b to the brake disc rotor 1 In the circumferential direction of the disk rotor 1, they are separated from each other and become forces in the opposite directions. Therefore, a large bending stress is generated in the brake disc rotor 1. This bending stress appears as distortion of the brake disc rotor 1 itself when the upper grindstone 9a and the lower grindstone 9b are separated from the brake disc rotor 1 after the completion of grinding. As a result, the runout of the brake disc rotor 1 cannot be reduced sufficiently.

  On the other hand, as shown in FIG. 14, in the grinding apparatus 10 of this embodiment, the upper grindstone 16 and the lower grindstone 18 are arranged (fixed) at the grinding positions P1 and P2, respectively, when the portion 58b to be ground is ground. Then, the portion 58b to be ground comes into contact with the upper grindstone 16 and the lower grindstone 18 from the outer peripheral surface 58c, and is then ground so as to enter between the upper grindstone 16 and the lower grindstone 18. That is, in the grinding apparatus 10, the portion to be ground 58 b is gradually ground from the outer peripheral side to the inner peripheral side by the upper grindstone 16 and the lower grindstone 18. In this case, it is possible to prevent a force from being applied in the thickness direction from the upper grindstone 16 and the lower grindstone 18 to the brake disc rotor 58 (grinding portion 58b). As a result, it is possible to prevent a bending stress from being generated in the brake disc rotor 58, and thus the runout of the brake disc rotor 58 can be sufficiently reduced. Further, in this case, the upper grindstone 9a and the lower grindstone 9b are located between and below the upper grindstone 16 and the portion 58b to be ground as compared with the conventional Inford type grinding apparatus in which the entire surfaces of the brake disk rotor 1 are ground simultaneously. Generation of a large contact resistance between the grindstone 18 and the portion to be ground 58b can be prevented. Thereby, since the driving force required for rotating the upper grindstone 16 and the lower grindstone 18 can be reduced, cheaper motors can be used as the grindstone drive motors 28 and 30. In addition, since a large driving force is not required to rotate the upper grindstone 16 and the lower grindstone 18, the grindstone drive motors 28 and 30 can be reduced in size. As a result, the grinding device 10 can be reduced in size and power consumption of the grinding device 10 can be reduced.

  Further, since the contact resistance between the upper grindstone 16 and the lower grindstone 18 and the brake disc rotor 58 is reduced, the force (clamping force) for fixing the brake disc rotor 58 on the support member 54 can be reduced. it can. Thereby, the deformation of the brake disc rotor 58 itself can be sufficiently prevented.

  In the grinding apparatus 10 of this embodiment, the grinding position P1 is located below the upper surface 58d of the portion to be ground 58b, and the grinding position P2 is located above the lower surface 58e of the portion to be ground 58b. The surface runout of the grinding part 58b can be reliably reduced.

  Moreover, in the grinding apparatus 10 of this embodiment, based on the current value of the workpiece drive motor 56 detected by the current detection unit 86, the determination unit 88 causes the contact position between the upper grindstone 16 and the portion to be ground 58b and the lower grindstone. The contact position between the portion 18 and the portion to be ground 58b can be detected. In this case, there is no need to separately provide a detection means for detecting the contact position between the upper grindstone 16 and the portion to be ground 58b and a detection means for detecting the contact position between the lower grindstone 18 and the portion to be ground 58b. The product cost of the grinding apparatus 10 can be reduced.

  Further, by detecting the current value of the work drive motor 56 by the common current detection unit 86, the change in the current value when the upper grindstone 16 and the portion to be ground 58b come into contact with each other, the lower grindstone 18 and the portion to be ground 58b, It is possible to detect a change in the current value at the time of contact with the same sensitivity. In this case, the grinding depth d1 (see FIG. 12) of the portion ground by the upper grindstone 16 until the contact position P4 (see FIG. 12) is detected on the upper surface 58d of the portion to be ground 58b, and the contact position on the lower surface 58e. It is possible to prevent a difference from occurring in the grinding depth d4 (see FIG. 12) of the portion ground by the lower grindstone 18 until P6 (see FIG. 12) is detected. Thereby, it is possible to prevent the intermediate position between the contact position P4 and the contact position P6 from greatly deviating from the center position C1 (see FIG. 12) in the thickness direction of the portion to be ground 58b. Therefore, the intermediate position between the grinding position P1 calculated based on the contact position P4 and the grinding position P2 calculated based on the contact position P6 is greatly deviated from the center position in the thickness direction of the portion to be ground 58b after grinding. Can be prevented. That is, the center position in the thickness direction of the portion to be ground 58b after grinding can be easily brought close to an ideal position (design position). As a result, the dimensional accuracy of the brake disc rotor 58 can be improved.

  The contact position between the upper grindstone 16 and the lower grindstone 18 and the portion 58b to be ground can be detected by detecting the current value of the grindstone drive motors 28 and 30, but the current value of the work drive motor 56 is detected. It is preferable. Usually, the capacity of the work drive motor 56 is considerably smaller than the capacity of the grindstone drive motor 28 and the grindstone drive motor 30 (about 1/10 to 1/15), so that the current value of the work drive motor 56 is the grindstone. It is more likely to change than the current value of the drive motors 28 and 30. Therefore, the current value of the work drive motor 56 changes quickly even when the upper grindstone 16 or the lower grindstone 18 and the brake disc rotor 58 are slightly in contact with each other. Therefore, by detecting the current value of the work drive motor 56, it is possible to accurately and quickly detect the contact position between the upper grindstone 16 and the lower grindstone 18 and the portion to be ground 58b.

  Further, in the grinding apparatus 10, the calculation unit 92 controls the grinding wheel cutting devices 32 and 34 for bringing the upper grinding wheel 16 and the lower grinding wheel 18 into contact with the part 58b to be ground, calculation of the grinding positions P1 and P2, and the upper grinding wheel. Control of the grindstone cutting devices 32 and 34 for moving the 16 and the lower grindstone 18 to the grinding positions P1 and P2 and control of the table drive motor 48 for performing grinding of the portion 58b to be ground are performed. That is, in the grinding apparatus 10, the grinding positions P1 and P2 are automatically calculated by the control of the calculation unit 92, and the grinding of the portion to be ground 58b is automatically executed. In this case, even when processing a plurality of brake disc rotors continuously, the operator does not need to set the grinding positions P1 and P2 for each brake disc rotor and execute the grinding process, so that the working efficiency is improved.

  In the grinding apparatus 10, the brake disc rotor 58 is fixed on the support member 54 (clamp jig 62) by pulling the clamper 60 downward by a draw bar 66 provided on the support member 54. Therefore, it is not necessary to provide a device for fixing the brake disc rotor 58 on the support member 54 on the clamper 60. In this case, since the space above the clamper 60 can be used as a space for performing work, work efficiency is improved. Moreover, since the structure of the grinding apparatus 10 can be made simple, the manufacturing cost of the grinding apparatus 10 can be reduced.

  Hereinafter, a case where the brake disc rotor is ground using a conventional in-feed type grinding device will be compared with a case where the brake disc rotor is ground using the grinding device 10 of this embodiment (Example).

  In the comparative example, the brake disc rotor was ground by the method described in FIG. As the upper grindstone and the lower grindstone, the same grindstone as the upper grindstone 16 and the lower grindstone 18 in FIG. 2 was used. CBN abrasive grains were used as the material for the grindstone segment. The rotational speed of the upper grindstone and the lower grindstone was 1000 rpm, and the rotational speed of the brake disc rotor was 200 rpm. The upper grindstone and the lower grindstone were rotated using the same components as the grindstone shafts 20 and 22, belts 24 and 26, and grindstone drive motors 28 and 30 in FIG. The brake disc rotor was rotated using the same components as the bearing 52a and the work drive motor 56 of FIG. Moreover, the upper whetstone and the lower whetstone were moved up and down using the same component as the grindstone cutting device 32 and 34 of FIG. In the comparative example, the contact positions of the upper grindstone and the lower grindstone and the brake disk rotor are detected by a method similar to the method in steps S4 and S8 in FIG. 7, and the detected contact positions are detected by the upper grindstone and the lower grindstone. It was set as the grinding start position.

  In the examples, CBN abrasive grains were used as materials for the grindstone segment 16b and the grindstone segment 18b. The rotational speeds of the upper grindstone 16 and the lower grindstone 18 were each 1000 rpm, and the rotational speed of the brake disk rotor was 200 rpm.

  In both the comparative example and the example, a brake disk rotor having an outer diameter (diameter) of 296 mm was used. In the comparative example, 8 brake disc rotors were ground, and in the example, 20 brake disc rotors were ground. The amount of grinding on the upper and lower surfaces of the brake disk rotor (corresponding to the depth d2 and the depth d5 in FIG. 12) was set to 0.12 mm.

  Tables 1 and 2 show the grinding results (changes in surface runout) of the comparative example and the example, respectively. Tables 1 and 2 show the runout (see the runout S1 in FIG. 12) of the upper surface of the brake disk rotor. Moreover, the average value in Table 1 and Table 2 is the value which rounded off after the decimal point.

  As shown in Table 1, in the comparative example, when the runout of the brake disc rotor before grinding was large, the runout could not be sufficiently reduced. On the other hand, as shown in Table 2, in the example, even when the surface runout of the brake disk rotor before grinding was large, the surface runout could be sufficiently reduced. In particular, even when the surface runout before grinding exceeded 100 μm, the surface runout could be reduced to less than 10 μm.

  In the comparative example and the example described above, the current value of the grindstone drive motor was measured simultaneously with the grinding of the brake disk rotor. The result is shown in FIG. FIG. 15A shows an example of the measurement result in the comparative example, and FIG. 15B shows an example of the measurement result in the example. In FIG. 15, the solid line indicates the current value of the grindstone driving motor that drives the upper grindstone, and the dotted line indicates the current value of the grindstone driving motor that drives the lower grindstone. In the comparative example shown in FIG. 15A, the brake disk rotor is ground in the period T1. The peaks A1 and A2 before the period T1 are generated when the upper grindstone and the lower grindstone are brought into contact with the brake disc rotor in order to calculate the grinding start positions of the upper grindstone and the lower grindstone. In the embodiment shown in FIG. 15B, the brake disk rotor is ground in the period T2. Peaks A3 and A4 before the period T2 contact the upper grindstone 16 and the lower grindstone 18 with the brake disc rotor in order to calculate the grinding positions P1 and P2 (see FIG. 12) of the upper grindstone 16 and the lower grindstone 18. Sometimes it happened.

  As shown in FIG. 15, in the comparative example, the current value of the grindstone drive motor is significantly increased in the period T1, but in the embodiment, the increase amount of the current value of the grindstone drive motors 28 and 30 in the period T2. Is small. Therefore, in the comparative example, a large contact resistance is generated between the upper grindstone and the lower grindstone and the brake disc rotor. However, in the embodiment, the upper grindstone 16, the lower grindstone 18 and the brake disc rotor It can be seen that there is no large contact resistance between them. Therefore, the grinding apparatus 10 used in the embodiment does not require a large driving force to rotate the upper grindstone 16 and the lower grindstone 18. Therefore, it is not necessary to use high-performance motors as the grindstone driving motors 28 and 30, and inexpensive motors can be used. Thereby, the product cost of the grinding device 10 can be reduced.

  In the above-described embodiment, the calculation unit 92 advances the brake disc rotor 58 to a position where the grinding of the upper surface 58d and the lower surface 58e of the portion to be ground 58b is completed in step S13, and then in step S14, the upper grindstone 16 and Although the lower grindstone 18 is returned to the original position, other processing may be performed after step S13 and before step S14. For example, after step S13 is completed, the upper grindstone 16 may be lowered and the lower grindstone 18 may be lifted to perform finish grinding of the upper surface 58d and the lower surface 58e. Moreover, after step S13 is complete | finished or after the above-mentioned finish grinding process, you may perform a spark out. Note that the term “spark out” refers to maintaining the rotation of the upper grindstone 16 and the lower grindstone 18 for a predetermined time while the positions of the upper grindstone 16 and the lower grindstone 18 in the vertical direction are fixed.

  In the above-described embodiment, as shown in FIG. 1, the brake disk rotor 58 is advanced between the upper grindstone 16 and the lower grindstone 18 by advancing the brake disc rotor 58 in the arrow X direction. The moving method of the brake disc rotor 58 is not limited to the above example. Hereinafter, it demonstrates using drawing.

  FIG. 16 is a plan view showing a grinding apparatus 10a according to another embodiment of the present invention. The grinding device 10a shown in FIG. 16 differs from the grinding device 10 shown in FIG. 1 in the following points.

  As shown in FIG. 16, in the grinding apparatus 10a, a pair of rails 42 are provided on the adjustment plate 38 so as to extend in the arrow Z direction (direction orthogonal to the arrow X direction in FIG. 1 in plan view). The slide table 44 has a roller 46 that rolls on the rail 42, and is movable along the rail 42 in the arrow Z direction. A table drive motor 48 is fixed on the adjustment plate 38. A rod-shaped moving screw 50 is fixed to a rotating shaft (not shown) of the table drive motor 48. The distal end side of the moving screw 50 is screwed to the slide table 44. The moving screw 50 is rotated by the rotational driving force of the table driving motor 48, and the slide table 44 moves in the arrow Z direction. A holding member (not shown) and a supporting member (not shown) similar to the holding member 52 of FIG. 1 and the supporting member 54 of FIG. 1 are provided on the slide table 44 on the column 12 side. The brake disc rotor 58 is fixed to the front. In such a configuration, by moving the slide table 44 in the arrow Z direction, the brake disc rotor 58 can be moved between the upper grindstone 16 and the lower grindstone 18.

  FIG. 17 is a plan view showing a grinding apparatus 10b according to still another embodiment of the present invention. The grinding apparatus 10b shown in FIG. 17 is different from the grinding apparatus 10 shown in FIG. 1 in the following points.

  As shown in FIG. 17, in the grinding apparatus 10b, a rotary table 94 is rotatably provided on the base 36. A table rotation motor 96 is provided in the base 36, and a rotation table 94 is fixed to a rotation shaft 98 of the table rotation motor 96. The rotational driving force of the table rotary motor 96 is transmitted to the rotary table 94 via the rotary shaft 98, and the rotary table 94 rotates in the direction of arrow R. On the rotary table 94, a holding member (not shown) and a supporting member (not shown) similar to the holding member 52 of FIG. 1 and the supporting member 54 of FIG. The brake disc rotor 58 is fixed on the support member. In such a configuration, by rotating the rotary table 94 in the direction of the arrow R, the brake disk rotor 58 can enter between the upper grindstone 16 and the lower grindstone 18. In this embodiment, the rotary table 94, the table rotary motor 96, and the rotary shaft 98 function as first moving means.

  In the above-described embodiment, the contact position between the upper grindstone 16 and the portion to be ground 58b and the contact position between the lower grindstone 18 and the portion to be ground 58b are detected based on the change in the current value of the work drive motor 56. However, the method for detecting the contact position between the upper grindstone 16 and the portion to be ground 58b and the contact position between the lower grindstone 18 and the portion to be ground 58b are not limited to the above example. For example, the contact position between the upper grindstone 16 and the portion to be ground 58b and the contact position between the lower grindstone 18 and the portion to be ground 58b based on the change in the drive torque of the workpiece drive motor 56 or the drive torque of the grindstone drive motors 28 and 30. It may be detected. In this case, a torque sensor is provided in the work drive motor 56 or the grindstone drive motors 28 and 30.

  In the above-described embodiment, the upper grindstone 16 is brought into contact with the portion to be ground 58b to calculate the grinding positions P1 and P2, and then the lower grindstone 18 is brought into contact with the portion to be ground 58b. The calculation method of P1 and P2 is not limited to the above example. For example, the upper grindstone 16 and the lower grindstone 18 may be simultaneously brought into contact with the portion to be ground 58b to calculate the grinding positions P1 and P2, and after the lower grindstone 18 is brought into contact with the portion to be ground 58b, the upper grindstone 16 is covered. The grinding positions P1 and P2 may be calculated in contact with the grinding part 58b.

  In the above-described embodiment, the grinding position P1 is located below the upper surface 58d of the portion to be ground 58b, and the grinding position P2 is located above the lower surface 58e of the portion to be ground 58b. The grinding position of the lower grindstone 18 is not limited to the above example. For example, the grinding position of the upper grindstone 16 may be above the position P7 in FIG. 12 (position where the outer edge b1 of the upper surface 58d is lowest), and the grinding position of the lower grindstone 18 is the position P8 (lower surface 58e in FIG. 12). The lower edge of the outer edge b2 may be lower.

10, 10a, 10b Grinding device 12 Column 16 Upper grinding wheel 18 Lower grinding wheel 20, 22 Grinding wheel shaft 28, 30 Grinding wheel drive motor 32, 34 Grinding wheel cutting device 36 Base 38 Adjustment plate 48 Table drive motor 50 Moving screw 54 Support member 56 Work drive motor 58 Brake disc rotor 58b Part to be ground 58d Upper surface 58e Lower surface 60 Clamper 66 Drawbar 84 ECU
94 Rotary table 96 Table rotary motor 98 Rotary shaft P1, P2 Grinding position

Claims (5)

A brake disk rotor grinding apparatus having a portion to be ground to be ground,
A support portion for supporting the brake disc rotor;
Driving means for rotating the brake disc rotor by applying a rotational driving force to the support portion;
An upper grindstone disposed and rotated at a first grinding position;
A lower grindstone disposed and rotated at a second grinding position below the first grinding position;
First moving means for moving the support portion so that the portion to be ground comes into contact with the upper grindstone and the lower grindstone from the outer peripheral surface thereof and then enters between the upper grindstone and the lower grindstone. , Brake disc rotor grinding device. Second moving means for moving the upper grindstone forward and backward with respect to the upper surface of the portion to be ground;
Third moving means for moving the lower grindstone back and forth with respect to the lower surface of the portion to be ground;
Detecting means for detecting a first contact position between the upper grindstone and the upper surface and a second contact position between the lower grindstone and the lower surface;
Control means for controlling the second moving means and the third moving means,
The driving means includes an electric motor,
The detecting means detects the first contact position and the second contact position based on a current value of the electric motor;
The control means controls the second moving means and the third moving means to bring the upper grindstone into contact with the upper surface and bring the lower grindstone into contact with the lower surface before grinding the portion to be ground. The brake disc rotor grinding apparatus according to claim 1, wherein the first grinding position and the second grinding position are calculated based on the first contact position and the second contact position detected by the detection means.   The control means calculates the first grinding position and the second grinding position, and then controls the second moving means and the third moving means to move the upper grindstone and the lower grindstone to the first grinding position. Then, the portion to be ground comes into contact with the upper grindstone at the first grinding position and the lower grindstone at the second grinding position from the outer peripheral surface by moving to the second grinding position and controlling the first moving means. Then, the grinding device for a brake disk rotor according to claim 2, wherein the support portion is moved so as to enter between the upper grindstone and the lower grindstone.   The supporting portion includes a rotating member rotated by the driving means, a clamper provided on the brake disc rotor for fixing the brake disc rotor on the rotating member, and a vertical direction provided in the rotating member. 4. The brake disc rotor grinding apparatus according to claim 1, further comprising a draw bar configured to be capable of moving forward and backward and being capable of being locked to the clamper. A method of grinding a brake disc rotor, wherein a grinding target portion of a brake disc rotor supported by a support portion is ground with a rotating upper grindstone and a lower grindstone,
Applying a rotational driving force to the support portion to rotate the brake disc rotor;
Placing the upper grindstone at the first grinding position;
Placing a lower grindstone at a second grinding position below the first grinding position;
A brake disc comprising: a step in which the portion to be ground comes into contact with the upper grindstone and the lower grindstone from an outer peripheral surface thereof, and then the support portion is moved so as to enter between the upper grindstone and the lower grindstone. Rotor grinding method.

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