JP7540254B2 - Grinding Equipment - Google Patents

Description

This disclosure relates to a grinding device.

Traditionally, traverse grinding methods have been used to grind the outer peripheral surface of a cylindrical workpiece that is longer than the width of the grinding wheel (see Patent Documents 1 and 2). In traverse grinding methods, the surface of the workpiece is ground while the grinding wheel is moved relatively along the rotation axis of the workpiece while rotating the workpiece. Then, when the end of the workpiece is reached, the grinding wheel is moved relatively in the opposite direction to grind the surface of the workpiece, or the grinding wheel is moved relatively in the opposite direction only without grinding, and then the grinding is performed while moving relatively again.

Japanese Patent Application Publication No. 48-70991 Japanese Patent Application Publication No. 55-58972

Conventional traverse grinding methods have the problem that, depending on the thickness to be ground, the grinding wheel must be moved back and forth a great number of times, which results in a very long grinding time. In addition, the grinding load is concentrated in an area of the grinding surface of the outer periphery of the grinding wheel, which is at the end of the direction of relative movement of the grinding wheel and has a width equivalent to the amount of movement of the grinding wheel along the axial direction of rotation per revolution of the workpiece (hereinafter referred to as "lead"), resulting in a short lifespan of the grinding wheel as a whole (the period during which the shape of the grinding wheel surface can be maintained). For this reason, a technology that can reduce the grinding time while preventing the lifespan of the grinding wheel from being shortened is desired.

The present disclosure can be realized in the following forms.
[Mode 1] A cylindrical grinding device that includes a disk-shaped grinding wheel, and performs traverse grinding by moving the grinding wheel and the workpiece relatively in a cutting direction that intersects with a rotation axis of a cylindrical workpiece, and moving the grinding wheel and the workpiece relatively in a traverse direction along the rotation axis, wherein the outer peripheral surface of the grinding wheel is formed with M (M is an integer of 2 or more) annular grinding surfaces that are stepped and continuous in the traverse direction, and the diameter of the grinding surface located at the rear in the traverse direction is larger than the diameter of the grinding surface located at the front,
The width of each of the M grinding surfaces is equal to the relative movement amount of the grinding wheel in the traverse direction per one rotation of the workpiece, the size of a radial step between adjacent grinding surfaces in the M grinding surfaces is equal to 1/M of a preset amount as a cutting amount in the cutting direction into the workpiece by the traverse grinding, the grinding wheel traverse grinds the workpiece in both the forward and backward movements in the traverse direction, and the M grinding surfaces are ground by a front grinding force in the forward movement. a number of annular grinding surfaces (N: an integer of 2 or more) that are stepped on the outer peripheral surface and grind the workpiece on the return path, the number of grinding surfaces being N (N is an integer of 2 or more) that are continuous in a stepped manner in the traverse direction and that grind the workpiece on the return path, the number of grinding surfaces being N, each having a larger diameter than the diameter of the grinding surface located at the rear of the return path, the number of widths of the N grinding surfaces being all equal to the amount of relative movement, and the size of each radial step between adjacent grinding surfaces among the N grinding surfaces being equal to 1/N of the set amount.

(1) As one embodiment of the present disclosure, there is provided a cylindrical grinding machine including a disk-shaped grinding wheel, which performs traverse grinding by moving the grinding wheel and the workpiece relative to each other in a cutting direction intersecting with a rotation axis of a cylindrical workpiece and moving the grinding wheel and the workpiece relative to each other in a traverse direction along the rotation axis. In this cylindrical grinding machine, the outer peripheral surface of the grinding wheel is provided with M (M is an integer of 2 or more) annular grinding surfaces that are stepped in the traverse direction, the M grinding surfaces being larger in diameter than the grinding surfaces located at the rear in the traverse direction, the widths of the M grinding surfaces being equal to the relative movement of the grinding wheel in the traverse direction per rotation of the workpiece, and the magnitudes of radial steps between adjacent grinding surfaces in the M grinding surfaces being equal to 1/M of a preset amount as the amount of cutting in the cutting direction into the workpiece by the traverse grinding.
According to this embodiment of the cylindrical grinding device, the width of each of the M grinding surfaces formed on the outer peripheral surface of the grinding wheel is equal to the relative movement of the grinding wheel in the traverse direction per revolution of the workpiece, and the magnitude of the radial step between adjacent grinding surfaces among the M grinding surfaces is equal to 1/M of a predetermined set amount as the amount of cutting into the workpiece by traverse grinding, so that for an area ground by 1/M of the predetermined set amount by a certain grinding surface during one revolution of the workpiece, it can be ground by 1/M of the predetermined set amount by an adjacent grinding surface during the next revolution. In this way, the workpiece can be ground by the predetermined cut amount while the grinding wheel moves relatively to the workpiece until it reaches the end of the workpiece. In addition, since the workpiece is ground using a grinding surface having a width M times the amount of relative movement of the grinding wheel in the traverse direction per revolution of the workpiece as the total grinding surface, the grinding area of the grinding wheel can be dispersed and the life of the grinding wheel can be prevented from being shortened compared to the conventional configuration in which the grinding surface has a width equal to the amount of relative movement of the grinding wheel in the traverse direction per revolution of the workpiece as the grinding surface. Thus, with the cylindrical grinding device of this form, the grinding time can be shortened while preventing the life of the grinding wheel from being shortened.
(2) In the cylindrical grinding device of the above embodiment, the outer peripheral surface may further be formed with a spark-out portion that is adjacent to and rearward of an Mth grinding surface that is located at the rearmost position in the traverse direction among the M grinding surfaces, has a diameter equal to that of the Mth grinding surface, and performs spark-out.
According to this form of cylindrical grinding device, a spark-out section that performs spark-out is formed, which is adjacent to the rear of the Mth grinding surface in the traverse direction, has the same diameter as the Mth grinding surface, and performs spark-out.Therefore, even if the central axis of the workpiece and the rotation axis are misaligned, spark-out can be performed after grinding by the M grinding surfaces, and the cross-sectional shape of the workpiece can be formed into a shape that is closer to a perfect circle.
(3) In the cylindrical grinding apparatus of the above embodiment, the grinding wheel traverse grinds the workpiece on both the forward and return paths of movement in the traverse direction, the M grinding surfaces grind the workpiece on the forward path, and the outer peripheral surface is provided with N (N is an integer of 2 or more) annular grinding surfaces that are stepped in the traverse direction and grind the workpiece on the return path, the N grinding surfaces having a larger diameter than the grinding surfaces located at the rear of the return path, the widths of the N grinding surfaces are all equal to the amount of relative movement, and the magnitudes of radial steps between adjacent grinding surfaces among the N grinding surfaces may all be equal to 1/N of the set amount.
According to this type of cylindrical grinding device, N grinding surfaces are further formed on the outer peripheral surface of the grinding wheel, and the workpiece is traverse-ground on both the outward and return paths of movement in the traverse direction, thereby shortening the grinding process time and making it possible to further expand (disperse) the grinding surfaces, thereby further preventing the life of the grinding wheel from being shortened.
(4) As another aspect of the present disclosure, there is provided a surface grinding device including a disk-shaped grinding wheel, and configured to perform grinding by moving at least one of the grinding wheel and the workpiece in a first direction and a second direction perpendicular to each other along the surface of a flat workpiece. In this surface grinding apparatus, the second direction is parallel to the rotation axis of the grinding wheel, P (P is an integer of 2 or more) annular grinding surfaces are formed on the outer peripheral surface of the grinding wheel in a stepped manner in the second direction, where the diameter of the grinding surface located at the rear in the second direction is larger than the diameter of the grinding surface located at the front, the P grinding surfaces have the same width as each other, the grinding wheel surface grinds the workpiece on both the forward and return paths of its movement in the first direction, and moves relatively in the second direction by a length equivalent to the width of the P grinding surfaces at the ends of the forward and return paths, respectively, and the magnitude of the radial step between adjacent grinding surfaces among the P grinding surfaces is all equal to 1/P, a preset set amount as the amount of cutting into the workpiece by the surface grinding.
According to this type of surface grinding device, the widths of the P grinding surfaces formed on the outer peripheral surface of the grinding wheel are all equal to the amount of relative movement in the second direction at the ends of the forward and return paths of the grinding wheel's movement in the first direction, and the magnitudes of the radial steps between adjacent grinding surfaces among the P grinding surfaces are all equal to 1/P of a predetermined set amount as the amount of cutting into the workpiece by surface grinding, so that for an area ground by 1/P of the predetermined set amount by a certain grinding surface on the forward path of the grinding wheel, it is possible to grind by 1/P of the predetermined set amount by an adjacent grinding surface on the return path. In this way, the workpiece can be ground by the predetermined amount of cutting while the grinding wheel reaches the end in the second direction. In addition, since the total grinding surface is a grinding surface having a width P times the amount of movement of the grinding wheel when it moves relatively in the second direction at the ends of the forward and return paths of the movement in the first direction, the grinding area of the grinding wheel can be dispersed and the life of the grinding wheel can be prevented from being shortened, compared to a configuration in which grinding is performed using a grinding surface having a width equal to the amount of movement of the grinding wheel when it moves relatively in the second direction at the ends of the forward and return paths of the movement in the first direction. Thus, with this type of surface grinding device, the grinding time can be shortened while preventing the life of the grinding wheel from being shortened.
The present disclosure may be realized in various forms, for example, in the form of a grinding wheel used in a cylindrical grinding apparatus or a surface grinding apparatus, a control method for a cylindrical grinding apparatus or a surface grinding apparatus, a grinding method for a workpiece, etc.

1 is a block diagram showing a schematic configuration of a grinding device according to an embodiment of the present disclosure. 1 is a plan view showing a schematic external shape of a workpiece to be cut by a grinding device; FIG. 4 is a partial cross-sectional view showing a detailed configuration of a radial end portion of the grinding wheel. FIG. 4 is a plan view showing a schematic diagram of relative movement of the grinding wheels during grinding. FIG. 11 is an explanatory diagram showing a schematic view of details of the grinding operation by the grinding wheel during the forward movement. FIG. 11 is a partial cross-sectional view showing a schematic detailed configuration of a grinding wheel in a grinding device according to a second embodiment. FIG. 11 is a plan view showing a schematic diagram of relative movement of the grinding wheels during grinding in the second embodiment. FIG. 11 is a block diagram showing a part of a schematic configuration of a grinding device according to a third embodiment. FIG. 11 is a partial external view showing a schematic detailed configuration of a grinding wheel in a grinding device according to a third embodiment. FIG. 13 is a perspective view showing a grinding wheel and a workpiece according to a fourth embodiment. FIG. 13 is a perspective view showing a schematic diagram of relative movement of the grinding wheels during grinding in the fourth embodiment.

A. First embodiment:
A1. Overall configuration of the grinding device:
FIG. 1 is a block diagram showing a schematic configuration of a grinding device 100 according to an embodiment of the present disclosure. In FIG. 1, an X1 axis, a Y1 axis, and a Z1 axis that are mutually perpendicular are shown. The X1-Y1 plane corresponds to a horizontal plane. The Z1 axis is parallel to the vertical direction. In this embodiment, the downward direction in FIG. 1, specifically, the direction from a grinding wheel head 48 to a table 40 described later along the Y1 axis, is called the "front side", and the direction from the table 40 to the grinding wheel head 48 along the Y1 axis is called the "rear side". In addition, the right side in FIG. 1, specifically, the direction from a headstock 30 to a tailstock 42 described later along the X1 axis, is called the "right side", and the direction from the tailstock 42 to the headstock 30 is called the "left side".

The grinding device 100 grinds the outer peripheral surface of the workpiece W1. At this time, the grinding device 100 performs traverse grinding by moving the grinding wheel (grinding wheel 46 described later) and the workpiece W1 relatively in a cutting direction intersecting with the rotation axis of the workpiece W1 (rotation axis CX described later), and moving the grinding wheel 46 and the workpiece W1 relatively in a traverse direction along the rotation axis CX. In this embodiment, the above-mentioned rotation axis is parallel to the X1 axis, and the cutting direction is perpendicular to the rotation axis and parallel to the Y1 axis. The grinding device 100 is also called a "cylindrical grinding device". In addition, as described later, the grinding wheel table (grinding wheel table 48 described later) advances and retreats in a direction perpendicular to the rotation axis of the workpiece W1 (rotation axis CX described later), so it is also called a "radial grinding machine". The grinding device 100 includes a bed 36, a table 40, a grinding wheel head 48, a headstock 30, a tailstock 42, and a sizing device 70.

The table 40, the grinding wheel head 48, and the sizing device 70 are attached to the upper surface (upper end surface in the Z1 axis direction) of the bed 36. In addition, the motors 24 and 54 are attached to the bed 36. The motor 24 is used to move the table 40 along the X1 axis direction. The amount of rotation of the motor 24 is detected by the encoder 22. The motor 24 and the encoder 22 are electrically connected to the table movement motor drive circuit 19. The table movement motor drive circuit 19 obtains the amount of rotation detected by the encoder 22 and uses this amount of rotation to control the rotation of the motor 24. The motor 54 is used to move the grinding wheel head 48 along the Y1 axis. The amount of rotation of the motor 54 is detected by the encoder 52. The motor 54 and the encoder 52 are electrically connected to the grinding wheel head movement motor drive circuit 18. The grinding wheel head movement motor drive circuit 18 obtains the number of rotations detected by the encoder 52 and uses this amount of rotation to control the rotation of the motor 54. In addition, a sliding surface is formed on the upper surface of the bed 36 for the table 40 to move along the X1 axis. Similarly, a sliding surface is formed on the upper surface of the bed 36 for the grindstone head 48 to move along the Y1 axis.

The table 40 is fitted with components for supporting, rotating and moving the workpiece W1. Specifically, the headstock 30 and the tailstock 42 are fitted to the table 40.

The grinding wheel head 48 moves and rotates the grinding wheel 46. The grinding wheel head 48 includes the grinding wheel 46, a mounting shaft 44 to which the grinding wheel 46 is attached, a motor 50, an endless belt 51, and a rotating shaft 53. The grinding wheel 46 has a disk-shaped external shape and is provided around the entire circumference of the mounting shaft 44. The detailed configuration of the grinding wheel 46 will be described later. In FIG. 1, the characteristic shape of the outer circumference of the grinding wheel 46, which will be described later, is enlarged to facilitate understanding. The endless belt 51 is stretched across the output shaft of the motor 50 and the rotating shaft 53. The rotating shaft 53 is connected to the grinding wheel 46 with its central axis aligned. Therefore, when the motor 50 rotates, the grinding wheel 46 rotates via the endless belt 51 and the rotating shaft 53. The rotation of the motor 50 is controlled by a drive circuit (not shown).

The headstock 30 includes a spindle 31, a chuck 32, a truing device 33, a motor 28, and an encoder 26. The spindle 31 functions as an axis for rotating the workpiece W1. Therefore, the central axis A0 of the spindle 31 coincides with the rotation axis of the workpiece W1 (rotation axis CX described later). The chuck 32 rotatably holds one end of the workpiece W1. One end of the chuck holds the end of the workpiece W1, and the other end is connected to the spindle 31. The truing device 33 is disposed on the outer peripheral surface of the headstock 30 on the side closer to the grinding head 48. The truing device 33 forms the surface shape of the grinding wheel 46 (the shape of the grinding surfaces BS1 to BS3 described later) into a predetermined shape. The motor 28 rotates the spindle 31. The amount of rotation of the motor 28 is detected by the encoder 26. The motor 28 and the encoder 26 are electrically connected to the spindle motor drive circuit 20.

The tailstock 42 faces the headstock 30 in the X1 axis direction and rotatably supports the end of the workpiece W1 opposite the end gripped by the chuck 32. The tailstock 42 has a center 38 that protrudes to the left along the X1 axis. The center 38 abuts against the right end face of the workpiece W1 to support the workpiece W1 and is configured to be rotatable in accordance with the rotation of the workpiece W1.

The sizing device 70 is disposed opposite the outer peripheral surface of the grinding wheel 46. The sizing device 70 is configured to be movable in the Y1-axis direction and is used to measure the outer diameter of the cylindrical portion of the workpiece W1.

The operation of the grinding machine 100 is controlled by a numerical control device 10. The numerical control device 10 includes a memory 1, a CPU 2, a first interface unit 3, and a second interface unit 4. A control program is stored in the memory 1 beforehand, and the CPU 2 executes various processes as a functional unit for controlling the grinding machine 100 by executing the control program. The first interface unit 3 mediates data transmission between the programmable logic controller (PLC) 14, the amplifier 16, the grinding wheel head movement motor drive circuit 18, the table movement motor drive circuit 19, and the spindle motor drive circuit 20 and the CPU 2. The second interface unit 4 mediates data transmission between the input/output device 12, which is composed of a keyboard, a display, etc., and the CPU 2. The programmable logic controller 14 controls the sizing device 70. The amplifier 16 amplifies the output of the sizing device 70 and also performs analog/digital conversion (A/D conversion).

The wheel head movement motor drive circuit 18 amplifies and outputs a drive control signal to the motor 54 in response to control instructions received from the CPU 2, and also servo-controls the motor 54 using the detection result of the encoder 52. Similarly, the table movement motor drive circuit 19 outputs a drive control signal to the motor 24, and also servo-controls the motor 24 using the detection result of the encoder 22. Similarly, the spindle motor drive circuit 20 outputs a drive control signal to the motor 28, and also servo-controls the motor 28 using the detection result of the encoder 26.

In the grinding device 100, the motor 24 rotates and the table 40 moves in the X1-axis direction, thereby allowing the grinding wheel 46 to move relative to the workpiece W1 in the X1-axis direction.

A2. Workpiece composition:
2 is a plan view showing a schematic external shape of the workpiece W1 to be cut by the grinding device 100. The workpiece W1 has a stepped cylindrical (columnar) external shape. The workpiece W1 includes a first columnar portion R1, two second columnar portions R2 arranged on either side of the first columnar portion R1, and two third columnar portions R3 in contact with the surface of each second columnar portion R2 opposite to the side in contact with the first columnar portion R1. The central axes of the columnar portions R1, R2, and R3 are aligned with each other and are aligned with the central axis A1 of the workpiece W1 as a whole.

The first cylindrical portion R1 has the largest diameter, the second cylindrical portion R2 has the second largest diameter, and the third cylindrical portion R3 has the smallest diameter. Therefore, a radial step ST is formed between the first cylindrical portion R1 and the second cylindrical portion R2. Similarly, a radial step is also formed between the second cylindrical portion R2 and the third cylindrical portion R3.

The workpiece W1 having the above configuration is used, for example, as a core material for a roller used in a rotary press for large-format printing such as newspapers after various processes such as cutting by the grinding device 100. When used as a core material for a roller in this way, it is used, for example, as a cylindrical member for filling the central shaft hole portion of a metallic cylindrical member.

In the roller described above, the workpiece W1 is required to be lightweight due to the requirement for high-speed rotation. For this reason, the workpiece W1 is formed, for example, by extrusion molding and sintering of CFRP (Carbon Fiber Reinforced Plastics). The workpiece W1 obtained through such materials and formation processes has low forming accuracy, so the grinding amount (cut amount) when grinding the surface to match the inner diameter of a metallic cylindrical member is very large. However, in the grinding device 100 of this embodiment, by using the grinding wheel 46 described later, the time required to grind the outer circumferential surface of the workpiece W1 can be shortened. In addition, the life of the grinding wheel 46 can be suppressed from being shortened. Note that the workpiece W1 is not limited to CFRP, and may be formed of any material, such as metals such as SUS (stainless steel) and titanium (Ti). In addition, the workpiece W1 is not limited to the core material of a roller used in a rotary press, and may be a cylindrical member used for any purpose.

A3. Detailed configuration of the grinding wheel 46:
3 is a partial cross-sectional view showing a detailed configuration of the radial end of the grinding wheel 46. A plurality of annular grinding surfaces are formed on the outer peripheral surface of the grinding wheel 46 in a stepped manner in the X1 axis direction. Since the X1 axis is parallel to the traverse direction, it can be said that a plurality of grinding surfaces are formed on the outer peripheral surface of the grinding wheel 46 in a stepped manner in the traverse direction. Specifically, the plurality of annular grinding surfaces correspond to a first grinding surface BS1, a second grinding surface BS2, and a third grinding surface BS3. These three grinding surfaces BS1 to BS3 come into contact with the workpiece W1 to grind the outer peripheral surface of the workpiece W1.

The first grinding surface BS1 is located furthest forward in the traverse direction and has the smallest diameter. The second grinding surface BS2 is adjacent to the rear of the first grinding surface BS1 in the traverse direction and has the second smallest diameter. The third grinding surface BS3 is adjacent to the rear of the second grinding surface BS2 in the traverse direction and has the largest diameter.

The width in the X1 axis direction (in other words, the width in the traverse direction) of the three grinding surfaces BS1 to BS3 is equal to one another and is equal to the relative movement amount 1L in the traverse direction of the grinding wheel 46 per rotation of the workpiece W1 (hereinafter also referred to as "lead 1L"). Lead 1L may be any value within the range of 10 to 20 mm (millimeters), for example. Note that lead 1L is not limited to a value within this range and may be any value.

In addition to the three grinding surfaces BS1 to BS3 described above, the first spark out portion SP1 is formed on the outer peripheral surface of the grinding wheel 46. The first spark out portion SP1 is located behind the third grinding surface BS3 in the traverse direction. The diameter of the first spark out portion SP1 is equal to the diameter of the third grinding surface BS3. The width of the first spark out portion SP1 in the traverse direction is twice the lead 1L (2L). The first spark out portion SP1 performs a so-called "spark out" by rotating itself. "Spark out" is also called zero cut. There is no difference in configuration between the third grinding surface BS3 and the first spark out portion SP1. The third grinding surface BS3 performs grinding (cutting) with a predetermined amount of cut, and the first spark out portion SP1, which corresponds to the two leads 1L located further back in the traverse direction, performs spark out for two leads (2L).

The size of the radial step between the first grinding surface BS1 and the second grinding surface BS2 is equal to the size of the radial step between the second grinding surface BS2 and the third grinding surface BS3. In this embodiment, the size of the step is equal to 1/3 of the set amount that is preset as the amount of cutting into the workpiece W1 in the cutting direction by traverse grinding. In this embodiment, the above-mentioned "preset amount" is "3Δ". Therefore, the size of the step is "1Δ", which is 1/3 of 3Δ. This 1Δ corresponds to the amount of cutting when each of the three grinding surfaces BS1 to BS3 cuts in the cutting direction. In FIG. 3, the cutting amount 1Δ of each grinding surface BS1 to BS3 is shown on the right side of the grinding wheel 46. The cutting amount 1Δ may be any value in the range of 10 to 20 μm (micrometers), for example. The cutting amount 1Δ is not limited to the value in this range and may be any value.

Each time traverse grinding is completed, the grinding surfaces BS1 to BS3 on the outer periphery of the grinding wheel 46 described above are shaped into the above-mentioned shape by the truing device 33.

A4. Grinding action:
4 is a plan view showing a schematic diagram of the relative movement of the grinding wheel 46 during grinding. When the table 40 moves from right to left along the X1 axis at a predetermined speed, the grinding wheel 46 moves from left to right along the X1 axis relative to the workpiece W1 at a predetermined speed. Conversely, when the table 40 moves from left to right along the X1 axis at a predetermined speed, the grinding wheel 46 moves from right to left along the X1 axis relative to the workpiece W1 at a predetermined speed.

The grinding wheel 46 shown by the thick solid line in FIG. 4 is positioned in the Y1 axis direction so that the grinding surfaces BS1 to BS3 are located at the step ST at the left end of the workpiece W1. Then, the grinding wheel 46 grinds the outer peripheral surface of the workpiece W1 while moving from left to right along the X1 axis relative to the workpiece W1, as shown by the forward path m11 indicated by the dashed arrow. When grinding is completed to the right end of the workpiece W1, the grinding wheel 46 moves from right to left along the X1 axis relative to the workpiece W1, as shown by the return path m12 indicated by the dashed arrow, to reach the left end of the workpiece W1. In this embodiment, the workpiece W1 is not ground in this return path m12. Then, the grinding wheel 46 moves to the front side as shown by the thin dashed arrow by moving the grinding wheel 46 to the front side along the Y1 axis. Then, in the same manner as before, the grinding wheel 46 grinds the outer peripheral surface of the workpiece W1 while moving relatively from left to right along the X1 axis with respect to the workpiece W1 as shown by the thin dashed line on the outward path m21, and moves from right to left along the X1 axis with respect to the workpiece W1 as shown by the thin dashed arrow on the return path m22. By repeating this grinding on the outward path and returning to the original position on the return path and moving further forward, the outer peripheral surface of the workpiece W1 can be ground to the desired thickness.

Figure 5 is an explanatory diagram showing the details of the grinding operation by the grinding wheel 46 during the forward movement. As described above, when the workpiece W1 rotates around the rotation axis CX, the grinding wheel 46 moves relatively in the X1-axis direction to grind the outer circumferential surface of the workpiece W1. When grinding starts, the first surface layer WL1 of the workpiece W1 is ground by the first grinding surface BS1 located at the right end. The thickness (length in the Y1-axis direction) of the first surface layer WL1 is equal to the cutting depth 1Δ. When the grinding wheel 46 grinds the lead 1L and moves relatively to the right, the second grinding surface BS2 then comes into contact with the surface of the workpiece W1, i.e., the second surface layer WL2 that appears as a result of grinding the first surface layer WL1, and grinds the second surface layer WL2. At this time, the first grinding surface BS1 also grinds the first surface layer WL1 by the lead 1L. The thickness (length in the Y1-axis direction) of the second surface layer WL2 is equal to the cutting depth 1Δ. After the first grinding surface BS1 and the second grinding surface BS2 have each ground the lead 1L, the third grinding surface BS3 then comes into contact with the surface of the workpiece W1, i.e., the third surface layer WL3 that has appeared as a result of the grinding of the second surface layer WL2, and grinds the third surface layer WL3. At this time, the first grinding surface BS1 and the second grinding surface BS2 grind the surface layers (the first surface layer WL1 and the second surface layer WL2) that they contact, by the lead 1L. The thickness (length in the Y1-axis direction) of the third surface layer WL3 is equal to the cutting depth 1Δ. Then, the first surface layer WL1 is ground by the first grinding surface BS1, the second surface layer WL2 is ground by the second grinding surface BS2, and the third surface layer WL3 is ground by the third grinding surface BS3, all at the same time. The third surface layer WL3 ground by the third grinding surface BS3 is sparked out by the first spark-out part SP1 during the relative movement of the next two leads by 1L (2L).

When one pass of grinding is completed as described above, the outer peripheral surface of the workpiece W1 is ground by the three grinding surfaces BS1 to BS3 by a preset amount (3Δ) as the amount of cutting in the cutting direction. In addition, when one pass of grinding is completed, the first spark-out unit SP1 performs two rotations of spark-out on each area. For example, in the comparative example configuration in which grinding is performed only by the lead 1L of the right end of the outer peripheral surface of the grinding wheel, at the time when one pass of grinding is completed, the workpiece W1 is only ground by the amount of cutting 1Δ. In addition, in the comparative example configuration, grinding is performed only by the lead 1L of the right end of the outer peripheral surface of the grinding wheel, so the grinding load is applied to that part. In contrast, the grinding device 100 of the first embodiment can grind three times the amount of cut in one grinding pass compared to the comparative example, and uses a grinding surface that is three times longer in the X1 axis direction compared to the comparative example, so the grinding load can be applied to a wider area. This makes it possible to further prevent the life of the grinding wheel 46 as a whole (the period during which the shape of the grinding wheel surface can be maintained) from becoming shorter.

According to the grinding device 100 of the first embodiment described above, the outer peripheral surface of the grinding wheel 46 is formed with a first grinding surface BS1, a second grinding surface BS2, and a third grinding surface BS3 that are stepped in the direction of the rotation axis CX. The width of each of the three grinding surfaces BS1 to BS3 in the direction of the rotation axis CX is equal to the relative movement amount (lead 1L) of the grinding wheel 46 in the traverse direction per rotation of the workpiece W1. In addition, the size of the radial step between the first grinding surface BS1 and the second grinding surface BS2 and the size of the radial step between the second grinding surface BS2 and the third grinding surface BS3 are equal to the relative movement amount (lead 1L) of the grinding wheel 46 in the traverse direction per rotation of the workpiece W1. The size of the radial step between the first grinding surface BS1 and the surface BS3 is equal to 1/3 of the preset amount (3Δ) as the amount of cutting into the workpiece W1 in the cutting direction by traverse grinding, so that the first grinding surface BS1 grinds the workpiece W1 by the amount of cutting 1Δ during one rotation of the workpiece W1, the second grinding surface BS2 grinds the workpiece W1 by the amount of cutting 1Δ during the next rotation of the same area, and the third grinding surface BS3 grinds the workpiece W1 by the amount of cutting 1Δ during the next rotation of the same area. Therefore, the workpiece W1 can be ground by the preset amount (3Δ) while the grinding wheel 46 moves relatively until it reaches the end of the workpiece W1. In addition, the workpiece W1 can be ground by using a grinding surface on the outer circumferential surface that is three times the width of the first grinding surface BS1 at the right end in the rotation axis direction, so that the grinding area can be distributed on the grinding wheel 46, and the life of the grinding wheel 46 can be prevented from being shortened. In this way, the grinding device 100 of the first embodiment can reduce the grinding time while preventing the life of the grinding wheel 46 from being shortened.

In addition, a first spark-out portion SP1 that performs spark-out is formed adjacent to the rear of the third grinding surface BS3, which is the rearmost grinding surface in the traverse direction, has the same diameter as the third grinding surface BS3, and performs spark-out. Therefore, even if the central axis A1 of the workpiece W1 is misaligned with the rotation axis CX, spark-out can be performed after grinding with the three grinding surfaces BS1 to BS3 to form the cross-sectional shape of the workpiece W1 into a shape closer to a perfect circle.

B. Second embodiment:
Fig. 6 is a partial cross-sectional view showing a schematic detailed configuration of a grinding wheel 146 in a grinding device 100 of a second embodiment. The grinding device 100 of the second embodiment differs from the grinding device 100 of the first embodiment in that it includes a grinding wheel 146 shown in Fig. 6 instead of the grinding wheel 46, and in that it grinds the outer peripheral surface of the workpiece W1 on the return path in addition to the forward path of movement in the traverse direction. Since the other configurations of the grinding device 100 of the second embodiment are similar to those of the grinding device 100 of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof will be omitted.

The grinding wheel 146 of the second embodiment differs from the grinding wheel 46 of the first embodiment in that it has a second spark out portion SP2 instead of the first spark out portion SP1, and in that it additionally has a fourth grinding surface BS4, a fifth grinding surface BS5, and a sixth grinding surface BS6. The rest of the configuration of the grinding wheel 146 is the same as that of the grinding wheel 46 of the first embodiment, so the same components are given the same reference numerals and detailed descriptions thereof are omitted.

The second sparkout portion SP2 performs sparkout in the same manner as the first sparkout portion SP1 of the first embodiment. The second sparkout portion SP2 is located on the opposite side of the third grinding surface BS3 from the second grinding surface BS2 along the X1 axis, and is adjacent to the third grinding surface BS3. The diameter of the second sparkout portion SP2 is equal to the diameter of the third grinding surface BS3. The width of the second sparkout portion SP2 in the traverse direction corresponds to the lead 1L. The diameter of the second sparkout portion SP2 is equal to the diameter of the third grinding surface BS3.

The three grinding surfaces BS4 to BS6 have a shape symmetrical to the three grinding surfaces BS1 to BS3 across the second spark-out portion SP2. Therefore, the three grinding surfaces BS4 to BS6 are stepped in the X1-axis direction, similar to the three grinding surfaces BS1 to BS3. Specifically, the fourth grinding surface BS4 is located on the opposite side of the second spark-out portion SP2 from the third grinding surface BS3, and is adjacent to the second spark-out portion SP2. The fifth grinding surface BS5 is located on the opposite side of the fourth grinding surface BS4 from the second spark-out portion SP2, and is adjacent to the fourth grinding surface BS4. The sixth grinding surface BS6 is located on the opposite side of the fifth grinding surface BS5 from the fourth grinding surface BS4, and is adjacent to the fifth grinding surface BS5. The diameter of the fourth grinding surface BS4 is equal to the diameter of the third grinding surface BS3. Similarly, the diameter of the fifth grinding surface BS5 is equal to the diameter of the second grinding surface BS2, and the diameter of the sixth grinding surface BS6 is equal to the diameter of the first grinding surface BS1. Therefore, the size of the radial step between the fourth grinding surface BS4 and the fifth grinding surface BS5 and the size of the radial step between the fifth grinding surface BS5 and the sixth grinding surface BS6 are both 1/3 (1Δ) of the above-mentioned set amount (3Δ). In addition, the width of the three grinding surfaces BS4 to BS6 in the direction of the rotation axis CX (width in the X1 axis direction) is common in that it is 1L. The three grinding surfaces BS4 to BS6 grind the workpiece W1 on the return path of the movement of the grinding wheel 46 in the traverse direction. The three grinding surfaces BS1 to BS3 grind the workpiece W1 on the outgoing path of the movement of the grinding wheel 46 in the traverse direction.

Figure 7 is a plan view that shows a schematic diagram of the relative movement of the grinding wheel 146 during grinding in the second embodiment. As described above, in the grinding device 100 of the second embodiment, the outer peripheral surface of the workpiece W1 is ground even on the return path during the grinding operation. Therefore, in the second embodiment, both the direction from left to right along the X1 axis and the direction from left to right correspond to the "traverse direction."

The grinding wheel 146 shown by the thick solid line in FIG. 7 grinds the outer peripheral surface of the workpiece W1 while moving from left to right along the X1 axis relative to the workpiece W1, as shown by the forward path m31 shown by the dashed arrow. At this time, the workpiece W1 is ground by the first grinding surface BS1, the second grinding surface BS2, and the third grinding surface BS3, so that the grinding amount (cutting depth) is the above-mentioned set amount (3Δ). In the second embodiment, in the next rotation after the third grinding surface BS3 has ground by the lead 1L, the second spark out part SP2 performs a spark out, and the fourth grinding surface BS4 acts as a spark out by another lead 1L.

When the grinding wheel 146 reaches the right end of the workpiece W1, unlike the first embodiment, the grinding wheel 146 moves forward along the Y1 axis by a cutting depth of 3Δ while maintaining the position of the X1 axis. Then, as the table 40 moves from left to right, the grinding wheel 146 moves from right to left relative to the workpiece W1, and grinding is performed on the return path.

In the return grinding, first, the sixth grinding surface BS6 located at the leftmost position of the grinding wheel 146 grinds the outer peripheral surface of the workpiece W1, i.e., the surface ground by the third grinding surface BS3 and sparked out by the second spark-out part SP2. After that, when the grinding wheel 146 grinds by lead 1L and moves relatively to the left, the fifth grinding surface BS5 grinds the surface of the workpiece W1, i.e., the surface revealed by grinding by the sixth grinding surface BS6. Furthermore, when the grinding wheel 146 grinds by lead 1L and moves relatively to the left, the fourth grinding surface BS4 grinds the surface of the workpiece W1, i.e., the surface revealed by grinding by the fifth grinding surface BS5. After that, the second spark-out part SP2 performs spark-out by lead 1L (one rotation), and the third grinding surface BS3 acts as a spark-out by another lead 1L. The grinding operation by the sixth grinding surface BS6, the fifth grinding surface BS5, and the fourth grinding surface BS4 on the return path, and the spark-out operation by the second spark-out unit SP2 are the same as the grinding operation by the first grinding surface BS1, the second grinding surface BS2, and the third grinding surface BS3 on the forward path, and the spark-out operation by the second spark-out unit SP2. When the grinding wheel 146 reaches the left end of the workpiece W1 in this way, the grinding operation on the forward path is completed. The surface of the workpiece W1 is ground by the above-mentioned set amount (3Δ) by this grinding operation on the forward path. Therefore, according to the grinding device 100 of the second embodiment, grinding (cutting) twice the above-mentioned set amount (6Δ) is performed by one round trip of the grinding wheel 146.

The grinding device 100 of the second embodiment described above has the same effect as the grinding device 100 of the first embodiment. In addition, since the fourth grinding surface BS4, the fifth grinding surface BS5, and the sixth grinding surface BS6 are formed on the outer peripheral surface of the grinding wheel 146, when the grinding wheel 146 moves relatively from right to left, the workpiece W1 can be ground by the first grinding surface BS1, the second grinding surface BS2, and the third grinding surface BS3, and when the grinding wheel moves relatively from right to left, the workpiece W1 can be ground by the fourth grinding surface BS4, the fifth grinding surface BS5, and the sixth grinding surface BS6. Therefore, the workpiece W1 is traverse ground in both the forward and backward directions in the traverse direction, so that the grinding processing time can be further shortened. In addition, since the grinding surface can be wider (more dispersed), the life of the grinding wheel 146 can be further suppressed from being shortened.

C. Third embodiment:
FIG. 8 is a block diagram showing a part of the schematic configuration of the grinding device 200 of the third embodiment. In the grinding device 200 of the third embodiment, a grinding wheel head (a grinding wheel head 248 described later) advances and retreats in a direction intersecting with the rotation axis A2 of the workpiece W1 at an acute angle θ. The grinding device 200 is also called an "angular grinding machine". The grinding device 200 of the third embodiment includes a bed 236, a table 240, a grinding wheel head 248, a headstock 230, a tailstock 242, and a truing device 243, similar to the grinding device 100 of the first embodiment. In addition, the grinding device 200 of the third embodiment includes a sizing device 70, motors 24, 54, encoders 22, 52, etc., similar to the grinding device 100 of the first embodiment. As in the first embodiment, the motors 24, 54 are controlled by the numerical control device 10 via the respective drive circuits 18, 19, 20 (not shown).

The bed 236 has the same function as the bed 36 in the first embodiment. Similarly, the table 240 has the same function as the table 40 in the first embodiment, the wheel head 248 has the same function as the wheel head 48 in the first embodiment, the headstock 230 has the same function as the headstock 30 in the first embodiment, the tailstock 242 has the same function as the tailstock 42 in the first embodiment, and the truing device 243 has the same function as the truing device 33 in the first embodiment. Note that in this embodiment, the truing device 243 is provided in the tailstock 242, not in the headstock 230.

The grinding wheel head 248 is configured to be movable forward and backward along the movement axis A3 by a motor (not shown). The grinding wheel head 248 has a motor 250. The motor 250 has the same function as the motor 50 in the first embodiment. That is, it drives the grinding wheel 246 to rotate. The rotation axis A4 of the grinding wheel 246 is perpendicular to the movement axis A3 of the grinding wheel head 248.

The table 240 is configured to be movable in the X1 axis direction, similar to the table 40 in the first embodiment. The rotation axis A2 of the workpiece W1 coincides with the central axis (not shown) of the workpiece W1. The angle θ between the movement axis A3 of the grinding wheel head 248 and the rotation axis A2 is an acute angle, as described above.

Figure 9 is a partial external view showing a schematic detailed configuration of the grinding wheel 246 in the grinding device 200 of the third embodiment. The grinding wheel 246 has a seventh grinding surface BS7, an eighth grinding surface BS8, a ninth grinding surface BS9, and a third spark-out portion SP3 on its outer circumferential surface. The three grinding surfaces BS7 to BS9 all have an annular external shape. The widths of the seventh grinding surface BS7, the eighth grinding surface BS8, and the ninth grinding surface BS9 in the X1-axis direction (the direction of the rotation axis CX) all coincide with the lead 1L. The three grinding surfaces BS7 to BS9 grind the outer circumferential surface of the workpiece W1. The seventh grinding surface BS7 is located on the leftmost side along the X1 axis on the outer circumferential surface of the grinding wheel 246. The eighth grinding surface BS8 is adjacent to the seventh grinding surface BS7 on the right side along the X1 axis. The ninth grinding surface BS9 is adjacent to the eighth grinding surface BS8 on the right side along the X1 axis. The diameter of the eighth grinding surface BS8 (average value of the diameter along the movement axis A3) is larger than the diameter of the seventh grinding surface BS7 (average value of the diameter along the movement axis A3). The diameter of the ninth grinding surface BS9 (average value of the diameter along the movement axis A3) is larger than the diameter of the eighth grinding surface BS8 (average value of the diameter along the movement axis A3).

The third sparkout portion SP3 performs sparkout in the same manner as the first sparkout portion SP1 of the first embodiment and the second sparkout portion SP2 of the second embodiment. The third sparkout portion SP3 has an annular external shape, is located on the opposite side of the ninth grinding surface BS9 from the eighth grinding surface BS8, and is adjacent to the ninth grinding surface BS9. The diameter of the third sparkout portion SP3 is equal to the diameter of the ninth grinding surface BS9. The width of the third sparkout portion SP3 in the X1 axis direction is equal to twice the lead 1L (2L).

Unlike the grinding device 100 of the first embodiment, the grinding wheel 246 having the above configuration grinds the outer peripheral surface of the workpiece W1 while moving relative to the workpiece W1 from right to left along the X1 axis.

The grinding device 200 of the third embodiment described above has the same effects as the grinding device 100 of the first embodiment.

D. Fourth embodiment:
Fig. 10 is a perspective view showing the grinding wheel 46 and the workpiece W2 in the fourth embodiment. In Fig. 10, the X2 axis, the Y2 axis, and the Z2 axis, which are perpendicular to each other, are shown. The X2-Y2 plane corresponds to the horizontal plane. The Z2 axis is parallel to the vertical direction. Fig. 11 is a perspective view showing the relative movement of the grinding wheel 46 during grinding in the fourth embodiment. For convenience of illustration, the grinding wheel 46 is omitted in Fig. 11.

The grinding device (not shown) in the fourth embodiment is a so-called surface grinding device, and performs surface grinding of the upper surface S1 of the workpiece W2. The workpiece W2 in this embodiment has a flat plate shape and is fixed to a table (not shown) so that its thickness direction is parallel to the Z2 axis direction and its upper surface S1 is parallel to the X2-Y2 plane. The table (not shown) is configured to be movable in the same manner as the table 40 in the first embodiment. Specifically, it is configured to be movable in the X2 axis direction and the Y2 axis direction. In the fourth embodiment, the direction from the end face S2 to the end face S3 shown in FIG. 11 along the X2 axis is called the "rear side along the X2 axis", and the direction from the end face S4 to the end face S5 along the X2 axis is called the "rear side along the Y2 axis". Also, in the fourth embodiment, the direction from the end face S3 to the end face S2 along the X2 axis is called the "front side along the X2 axis", and the direction from the end face S5 to the end face S4 along the Y2 axis is called the "front side along the Y2 axis".

The direction along the X2 axis in the fourth embodiment corresponds to the "first direction" in this disclosure, and the direction along the Y2 axis corresponds to the "second direction" in this disclosure.

The grinding wheel 46 of the fourth embodiment has a similar configuration to the grinding wheel 46 of the first embodiment. Therefore, the same components of the grinding wheel 46 of the fourth embodiment as those of the grinding wheel 46 of the first embodiment are given the same reference numerals, and detailed description thereof is omitted. The grinding wheel 46 of the fourth embodiment is arranged so that the central axis A5 shown in FIG. 10 is parallel to the Y2-axis direction. As the workpiece W2 moves in the X2-axis direction and the Y2-axis direction, the grinding wheel 46 moves relative to the workpiece W2 in the X2-axis direction and the Y2-axis direction.

As shown in FIG. 11, before grinding starts, the grinding wheel 46 is positioned so as to overlap the workpiece W2 in the Z2-axis direction by the lead 1L at a position closer to the front end surface S2 along the X-axis of the workpiece W2. From this state, the grinding wheel 46 moves relatively from the front side to the rear side along the X2-axis, as shown by the forward path m51 indicated by the dashed arrow. At this time, the first grinding surface BS1 of the grinding wheel 46 performs a cut of 1Δ. When the grinding wheel 46 reaches the rear end of the workpiece W2 along the X2-axis, the grinding wheel 46 performs a relative movement m61 from the rear side to the front side along the Y2-axis. The length of this relative movement m61 is the same as the lead 1L. After that, the grinding wheel 46 moves relatively from the rear side to the front side along the X2-axis, as shown by the return path m52 indicated by the dashed arrow. At this time, the part ground in the forward path m51 is now ground by the second grinding surface BS2 by the cutting depth of 1Δ. Also, a new part is ground by the first grinding surface BS1 by the cutting depth of 1Δ. When the grinding wheel 46 reaches the end of the front side of the workpiece W2, the grinding wheel 46 executes a relative movement m62 from the rear side to the front side along the Y2 axis. The length of this relative movement m62 is the same length as the lead 1L. From this state, the grinding wheel 46 again moves from the front side to the rear side along the X2 axis as shown by the forward path m53 indicated by the dashed arrow. At this time, the part ground by the second grinding surface BS2 in the return path m52 is now ground by the third grinding surface BS3 by the cutting depth of 1Δ. Therefore, the portion ground by the first grinding surface BS1 on the outward path m51, i.e., the region with a length in the Y2-axis direction equivalent to 1L of lead, is ground (cut) by a preset amount (3Δ) as the cutting depth. Also, the portion ground by the first grinding surface BS1 on the return path m52 is then ground by the second grinding surface BS2 by the cutting depth (1Δ). In this way, by repeatedly performing a relative movement of 1L of lead from the back side to the front side along the Y axis at the ends of the outward and return paths while reciprocating in the X2-axis direction, the entire region of the upper surface S1 is ground by the set amount (3Δ) in the Z2-axis direction.

According to the grinding device of the fourth embodiment described above, three grinding surfaces BS1 to BS3 are formed on the outer peripheral surface of the grinding wheel 46, which are stepped in the Y2-axis direction. The widths of the first grinding surface BS1, the second grinding surface BS2, and the third grinding surface BS3 in the direction of the central axis A5 are all equal to the relative movement amount (lead 1L) of the grinding wheel 46 in the Y2-axis direction. In addition, the size of the radial step between the first grinding surface BS1 and the second grinding surface BS2 and the width of the third grinding surface BS3 in the direction of the central axis A5 are all equal to the relative movement amount (lead 1L) of the grinding wheel 46 in the Y2-axis direction. Since the size of the radial step with the third grinding surface BS3 is equal to 1/3 of the preset set amount (3Δ) as the cutting-in amount into the workpiece W2 by surface grinding, the first grinding surface BS1 can grind the workpiece W2 by the cutting-in amount of 1Δ while the grinding wheel 46 moves relatively from the rear side to the front side along the X2 axis, and the second grinding surface BS2 can grind the workpiece W2 by the cutting-in amount of 1Δ while the grinding wheel 46 moves relatively from the rear side to the front side along the X2 axis. Similarly, the second grinding surface BS2 can grind the workpiece W2 by the cutting-in amount of 1Δ while the grinding wheel 46 moves relatively from the rear side to the front side along the X2 axis, and the third grinding surface BS3 can grind the workpiece W2 by the cutting-in amount of 1Δ while the grinding wheel 46 moves relatively from the rear side to the front side along the X2 axis. Therefore, the upper surface S1 of the workpiece W2 can be ground by a preset amount (3Δ) while the grinding wheel 46 reaches the front end of the workpiece W2 in the Y2-axis direction, thereby shortening the grinding processing time. In addition, the workpiece W2 can be ground using a grinding surface three times the width of the first grinding surface B1 in the Y2-axis direction, so the grinding area can be dispersed in the grinding wheel 46, and the life of the grinding wheel 46 can be prevented from being shortened. In this way, according to the grinding device of the fourth embodiment, like the grinding device 100 of the first embodiment, the grinding processing time can be shortened while preventing the life of the grinding wheel 46 from being shortened.

E. Other embodiments:
(E1) In each embodiment, the relative movement of the grinding wheels 46, 146, 246 is realized by moving the tables 40, 240, but the present disclosure is not limited to this. Instead of the tables 40, 240, or in addition to the tables 40, 240, the relative movement may be realized by moving the wheel heads 48, 248. In this configuration, the wheel heads 48, 248 of the first to fourth embodiments are configured to be movable in a direction parallel to the rotation axis of the workpiece W1. Moreover, the wheel head of the fifth embodiment is configured to be movable in the X2 axis direction and the Y2 axis direction.

(E2) In each embodiment, dressing (sharpening) may be performed between relative movements of the grinding wheel 46. For example, in each embodiment, dressing may be performed between the forward and return passes.

(E3) In each embodiment, the number of grinding surfaces of the grinding wheels 46, 146 is three or more, but the present disclosure is not limited to this. It may be any integer of two or more. For example, in a configuration in which the number of grinding surfaces is four, the size of the radial step between adjacent grinding surfaces is set to 1/4 of a preset amount as the cutting amount in the cutting direction, thereby achieving the same effect as each embodiment. That is, in general, in the first to third embodiments, a configuration in which M (M is an integer of 2 or more) annular grinding surfaces are formed on the outer peripheral surface of the grinding wheels 46, 146, 246 in a stepped manner in the traverse direction may be adopted. Note that in the second embodiment, M (M is an integer of 2 or more) grinding surfaces for grinding the workpiece W1 on the outward path may be provided, and N (M is an integer of 2 or more) grinding surfaces for grinding the workpiece W1 on the return path may be provided. In addition, in the fourth embodiment, a configuration may be adopted in which P (P is an integer of 2 or more) annular grinding surfaces are formed in a stepped manner on the outer circumferential surface of the grinding wheel 46 in the second direction (Y2 axis direction). These configurations also have the same effects as the other embodiments.

(E4) In each embodiment, the grinding device 100, 200 may include at least one of three drive circuits 18-20, a programmable logic controller 14, an amplifier 16, a numerical control device 10, and an input/output device 12.

(E5) The width of the spark out portion in each embodiment is merely an example and is not limited to the size shown in each embodiment. For example, in the first and fourth embodiments, the width of the first spark out portion SP1 is two leads (2L), but it may be any lead size, such as one lead (1L) or three leads (3L), or the width of the first spark out portion SP1 may be 0 (zero), i.e., the first spark out portion SP1 may be omitted. Similarly, in the second embodiment, the width of the second spark out portion SP2 may be any lead size, or the second spark out portion SP2 may be omitted. Also, in the third embodiment, the width of the third spark out portion SP3 may be any lead size, or the third spark out portion SP3 may be omitted.

The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in each form described in the Summary of the Invention column can be replaced or combined as appropriate to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described in this specification as essential, it can be deleted as appropriate.

1...Memory, 1L...Lead (relative movement amount), 2...CPU, 3...First interface unit, 4...Second interface unit, 10...Numerical control device, 12...Input/output device, 14...Programmable logic controller, 16...Amplifier, 18...Grinding wheel head movement motor drive circuit, 19...Table movement motor drive circuit, 20...Spindle motor drive circuit, 22...Encoder, 24...Motor, 26...Encoder, 28...Motor, 30...Spindle stock, 230...Spindle stock, 31...Spindle, 32 ...Chuck, 33...Truing device, 243...Truing device, 36...Bed, 236...Bed, 38...Center, 40...Table, 240...Table, 42...Tailstock, 242...Tailstock, 44...Mounting shaft, 46...Grinding wheel, 146...Grinding wheel, 246...Grinding wheel, 48...Grinding wheel head, 248...Grinding wheel head, 50...Motor, 250...Motor, 51...Endless belt, 52...Encoder, 53...Rotating shaft, 54...Motor, 70...Sizing device, 100...Grinding device, 200...Grinding device, A0...center axis, A1...center axis, A2...rotation axis, A3...movement axis, A4...rotation axis, A5...center axis, BP1...ground portion, BP2...ground portion, BP3...ground portion, BP4...ground portion, BS1...first ground surface, BS2...second ground surface, BS3...third ground surface, BS4...fourth ground surface, BS5...fifth ground surface, BS6...sixth ground surface, BS7...seventh ground surface, BS8...eighth ground surface, BS9...ninth ground surface, CX...rotation axis, R1...first cylindrical portion, R2...second cylindrical portion, R3...third cylindrical portion part, S1...upper surface, S2...end face, S3...end face, S4...end face, S5...end face, SP1...first spark out part, SP2...second spark out part, SP3...third spark out part, ST...step, W1...workpiece, W2...workpiece, WL1...first surface part, WL2...second surface part, WL3...third surface part, m11...outward path, m12...return path, m21...outward path, m22...return path, m31...outward path, m51...outward path, m52...return path, m53...outward path, m61...relative movement, m62...relative movement

Claims (2)

A cylindrical grinding device that includes a disk-shaped grinding wheel, and performs traverse grinding by moving the grinding wheel and the workpiece relatively in a cutting direction that intersects with a rotation axis of the cylindrical workpiece, and moving the grinding wheel and the workpiece relatively in a traverse direction along the rotation axis,
The grinding wheel has an outer peripheral surface formed with M (M is an integer of 2 or more) annular grinding surfaces that are continuous in a stepped manner in the traverse direction, and the diameter of the grinding surface located at the rear in the traverse direction is larger than the diameter of the grinding surface located at the front,
The widths of the M grinding surfaces are all equal to the relative movement amount of the grinding wheel in the traverse direction per rotation of the workpiece,
a size of a radial step between adjacent grinding surfaces among the M grinding surfaces is equal to 1/M of a predetermined set amount as a cutting amount in the cutting direction of the workpiece by the traverse grinding ,
The grinding wheel traverse-grinds the workpiece in both the forward and backward directions of movement in the traverse direction;
The M grinding surfaces grind the workpiece on the outward path,
the outer circumferential surface is formed with N (N is an integer of 2 or more) annular grinding surfaces which are stepped in the traverse direction and grind the workpiece on the return path, the N grinding surfaces being larger in diameter than the grinding surfaces located at the rear and front of the return path;
The widths of the N grinding surfaces are all equal to the amount of relative movement,
The magnitude of the radial step between adjacent grinding surfaces in the N grinding surfaces is equal to 1/N of the set amount.
Cylindrical grinding equipment. 2. The cylindrical grinding apparatus according to claim 1,
The outer circumferential surface is further provided with a spark-out portion that is adjacent to an M-th grinding surface located at the rearmost position in the traverse direction among the M grinding surfaces, has a diameter equal to that of the M-th grinding surface, and performs spark-out.
Cylindrical grinding equipment.

Images