JP2013184237A - Surface grinding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface grinding machine capable of reducing or preventing inclination of a movable table during grinding.SOLUTION: A surface grinding machine 100 including an X-axis table 2 supporting a workpiece W is provided with a table moving mechanism 20 moving the X-axis table 2, and a gravity center position adjusting mechanism 21 that adjusts the position of the center of gravity GC of a moving body moved by the table moving mechanism 20. The moving body includes the workpiece W, X-axis table 2 and gravity center position adjusting mechanism 21.

Description

  The present invention relates to a surface grinder, and more particularly to a surface grinder provided with a movable table on which an object to be ground is placed.

  2. Description of the Related Art Conventionally, a portal planer having a reciprocating table supported by a hydrostatic bearing mechanism so as to reciprocate on a bed is known (see, for example, Patent Document 1).

  This hydrostatic bearing mechanism supplies the pressure oil discharged from the metering discharge pump to each of the plurality of pockets located on the lower surface of the reciprocating table and facing the sliding rail on the upper surface of the bed. Make the gap between them uniform.

  The hydrostatic bearing mechanism includes a gap sensor at a position corresponding to each of the plurality of pockets, and detects an actual gap amount between the reciprocating table and the slide rail at a specific pocket position. Then, when the actual gap amount falls below the set gap amount, the actual gap amount is adjusted to be the set gap amount by increasing the discharge amount of the metering discharge pump corresponding to the specific pocket.

  In this way, the hydrostatic bearing mechanism of Patent Document 1 prevents the reciprocating table on which the workpiece as the workpiece is placed from moving while being tilted.

JP 2001-132748 A

  However, this hydrostatic bearing mechanism is configured to increase the discharge amount of the metering discharge pump after detecting the decrease in the gap amount so as to cancel the decrease in the gap amount. Can not be prevented. As a result, the hydrostatic bearing mechanism described in Patent Document 1 cannot prevent a reduction in machining accuracy.

  In view of the above points, an object of the present invention is to provide a surface grinding machine that can reduce or prevent the occurrence of tilting of a movable table during grinding.

  In order to achieve the above object, a surface grinding machine according to an embodiment of the present invention is a surface grinding machine including a movable table that supports an object to be ground, and includes a table moving mechanism that moves the movable table, A center of gravity position adjusting mechanism that adjusts the position of the center of gravity of the moving body moved by the table moving mechanism, and the moving body includes the workpiece, the movable table, and the center of gravity position adjusting mechanism. To do.

  By the above-described means, the present invention can provide a surface grinder that can reduce or prevent the occurrence of tilting of the movable table during grinding.

It is a front view of the surface grinding machine concerning the example of the present invention. It is a top view of the surface grinder of FIG. It is a perspective view of the table moving mechanism and center-of-gravity position adjustment mechanism in the surface grinder of FIG. FIG. 4 is an elevational sectional view of the table moving mechanism and the gravity center position adjusting mechanism of FIG. 3. FIG. 4 is a side sectional view of the table moving mechanism and the gravity center position adjusting mechanism of FIG. 3. It is a figure explaining adjustment of the gravity center position of a movable body by a gravity center position adjustment mechanism. It is a figure explaining an example of the determination method of the position of the block for adjustment in a gravity center position adjustment mechanism. It is a figure which shows the relationship between the speed and acceleration of a moving body, and a pitching angle when an X-axis table is reciprocated in the X-axis direction. It is a figure which shows the time transition of the pitching angle of a moving body when an X-axis table is reciprocated in the X-axis direction.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a front view of a surface grinding machine 100 according to an embodiment of the present invention, and FIG. 2 is a top view thereof. The surface grinding machine 100 mainly includes a main body bed 1, an X-axis table 2, a horizontal axis grinding wheel column 3, a horizontal axis grinding wheel head 4, a grinding wheel head rotating motor 5, a grinding wheel head vertical feed motor 6, and a grinding wheel head left and right feeding. Motor 7, table driving motor 8, and control device 9.

  The main body bed 1 is a pedestal that supports the X-axis table 2 so as to reciprocate in the X-axis direction. Specifically, the main body bed 1 has rail grooves 1AL and 1AR for receiving guide rails protruding from the lower surface of the X-axis table 2 on its upper surface.

  The X-axis table 2 is a table that can slide on the main body bed 1 in the X-axis direction, and supports an object (workpiece) W to be ground on its upper surface.

  The horizontal axis grinding wheel column 3 is a device that supports the horizontal axis grinding wheel head 4 so as to be movable in the vertical direction (Z-axis direction) and the horizontal direction (Y-axis direction).

  The horizontal-axis grindstone head 4 is a grindstone head having a grindstone shaft 40 extending in parallel with the horizontal direction (X-axis direction). In the present embodiment, a grinding wheel 41 is attached to the tip of the grinding wheel shaft 40.

  The grindstone head rotating motor 5 is a motor that rotates the grindstone shaft 40 of the horizontal axis grindstone head 4, and for example, an AC servo motor is used.

  The grinding wheel head vertical feed motor 6 is a motor that drives a grinding wheel head vertical movement mechanism for moving the horizontal grinding wheel head 4 in the vertical direction (Z-axis direction). In this embodiment, the grinding wheel head vertical feed motor 6 is an AC servo motor for rotating a ball screw shaft or a ball screw nut in a ball screw mechanism that moves the horizontal grinding wheel head 4 in the Z-axis direction.

  The grindstone head left / right feed motor 7 is a motor that drives a grindstone head left / right movement mechanism for moving the horizontal axis grindstone head 4 in the left / right direction (Y-axis direction). In this embodiment, the grindstone head left-right feed motor 7 is an AC servomotor for rotating a ball screw shaft or a ball screw nut in a ball screw mechanism that moves the horizontal axis grindstone head 4 in the Y-axis direction.

  Note that the vertical movement mechanism and the horizontal movement mechanism may be other mechanisms such as a rack and pinion mechanism.

  The table drive motor 8 is a motor that drives an X-axis table moving mechanism for moving the X-axis table 2 in the X-axis direction.

  The control device 9 is a device that controls the movement of the surface grinding machine 100, and is, for example, a computer including a CPU, a RAM, a ROM, and the like.

  Specifically, the control device 9 controls the table driving motor 8 to move the workpiece W on the X-axis table 2 to a predetermined position. Further, the control device 9 controls the grinding wheel head vertical feed motor 6 and the grinding wheel head lateral feed motor 7 to move the horizontal axis grinding wheel head 4 to a predetermined position.

  Thereafter, the control device 9 controls the grindstone head rotating motor 5 to start the rotation of the horizontal axis grindstone head 4, and controls the table driving motor 8 to move the X-axis table 2 in the + X direction. The grinding wheel 41 is brought into contact with the workpiece W to start the first grinding process.

  When the X-axis table 2 is moved to a predetermined position in the + X direction by the table driving motor 8, that is, when the first grinding process for the workpiece W by the grinding wheel 41 is completed, the control device 9 moves the X-axis table 2 to -X. Move it back to the original position. At that time, the control device 9 may raise the horizontal axis grinding wheel head 4 by the grinding wheel head vertical feed motor 6. This is to prevent the horizontal axis grinding wheel head 4 from coming into contact with the workpiece W when the X-axis table 2 is returned to its original position. At this time, the control device 9 may temporarily stop the grindstone head rotating motor 5.

  Thereafter, the control device 9 rotates the horizontal axis grinding wheel head 4 by the grinding wheel head rotating motor 5 and lowers the horizontal axis grinding wheel head 4 by the grinding wheel head vertical feed motor 6. Then, the control device 9 controls the table driving motor 8 to move the X-axis table 2 in the + X direction, brings the grinding wheel 41 into contact with the workpiece W, and starts the second grinding process.

  By repeating the above-described movement, the control device 9 performs grinding of the workpiece W.

  Next, the table moving mechanism 20 and the gravity center position adjusting mechanism 21 will be described with reference to FIGS. FIG. 3 is a perspective view of the table moving mechanism 20 and the gravity center position adjusting mechanism 21. 4 is a vertical sectional view of the vertical plane including the alternate long and short dash line in FIG. 3 viewed from the direction indicated by arrow IV, and FIG. 5 illustrates the vertical plane including the alternate long and short dash line in FIG. FIG. FIG. 4 is also an elevational cross-sectional view of a vertical plane including the alternate long and short dash line as viewed from the direction indicated by arrow IV. In FIG. 3, the main body table 1 is not shown for the sake of clarity.

  The table moving mechanism 20 is a mechanism that reciprocates the X-axis table 2 in the X-axis direction, and mainly includes a cylinder 20A, a first shaft 20BF, a second shaft 20BB, and a piston 20C.

  The cylinder 20 </ b> A is fixed to the lower surface of the X-axis table 2 and moves in the X-axis direction on the main body bed 1 together with the X-axis table 2. The cylinder 20A includes a cylindrical space 20As (see FIG. 5) inside, and receives the piston 20C in the cylindrical space 20As so that the piston 20C can slide relative to the inner wall of the cylindrical space 20As. As shown in FIG. 5, the cylindrical space 20As is separated into a first cylindrical space 20As1 and a second cylindrical space 20As2 by a piston 20C.

  The first shaft 20BF is a cylindrical member having one end fixed to the + X side surface of the piston 20C and the other end fixed to an external stationary object (not shown). Similarly, the second shaft 20BB is a cylindrical member having one end fixed to the −X side surface of the piston 20C and the other end fixed to an external stationary object. The external stationary object may be any object that can hold the cylinder 20A, the first shaft 20BF, and the second shaft 20BB stationary when the X-axis table 2 is moved. Also good.

  Piston 20C is a disk member accommodated in cylindrical space 20As so that it can move relatively with respect to the inner wall of cylindrical space 20As within cylindrical space 20As of cylinder 20A. The piston 20C has a + X side surface connected to the first shaft 20BF, and a −X side surface connected to the first shaft 20BF.

  With such a configuration, the cylinder 20 </ b> A can reciprocate with respect to the main body bed 1 together with the X-axis table 2, while the first shaft 20 </ b> BF, the second shaft 20 </ b> BB, and the piston 20 </ b> C are attached to the main body bed 1. It arrange | positions so that it may stand still with respect to it.

  More specifically, the X-axis table 2 includes a top plate portion 2A, two V-shaped guide rails 2BL and 2BR protruding in the −Z direction from the lower surface of the top plate portion 2A, and the Y axis of the top plate portion 2A. Side plate portions 2CL and 2CR extending in the −Z direction from both ends of the direction. Further, the X-axis table 2 is supported by the main body table 1 so that it can reciprocate on the main body table 1 in the X-axis direction using a hydrostatic bearing mechanism. Specifically, in the hydrostatic bearing mechanism, an oil film is formed between the rail grooves 1AL and 1AR on the upper surface of the main body table 1 and the guide rails 2BL and 2BR, so that the X-axis table 2 is mounted on the main body bed 1. To be supported in a floating state.

  The reciprocating movement of the X-axis table 2 in the X-axis direction includes a hydraulic pump (not shown) driven by the table driving motor 8 and an electromagnetic switching valve (not shown) that controls the flow of hydraulic oil discharged from the hydraulic pump. (Not shown). Specifically, when the X-axis table 2 is moved in the + X direction, the hydraulic oil discharged from the hydraulic pump passes through the first shaft 20BF and the first cylindrical space 20As1 of the cylinder 20A as shown by the dotted line in FIG. Flow into. On the other hand, the hydraulic oil in the second cylindrical space 20As2 of the cylinder 20A passes through the second shaft 20BB and is discharged to a hydraulic oil tank (not shown). As a result, the volume of the first cylindrical space 20As1 is increased, the volume of the second cylindrical space 20As2 is decreased, and the X-axis table 2 is moved in the + X direction as indicated by an arrow AR in FIG.

  Similarly, when the X-axis table 2 is moved in the −X direction, the hydraulic oil discharged from the hydraulic pump flows into the second cylindrical space 20As2 of the cylinder 20A through the second shaft 20BB. On the other hand, the hydraulic oil in the first cylindrical space 20As1 of the cylinder 20A passes through the first shaft 20BF and is discharged to a hydraulic oil tank (not shown). As a result, the volume of the first cylindrical space 20As1 decreases, the volume of the second cylindrical space 20As2 increases, and the X-axis table 2 is moved in the −X direction.

  Note that, as described above, the first shaft 20BF, the second shaft 20BB, and the piston 20C remain stationary with respect to the main body bed 1 even when the X-axis table 2 moves.

  The center-of-gravity position adjustment mechanism 21 is a mechanism that adjusts the position of the center of gravity GC of the moving body that is moved by the table moving mechanism 20, and mainly includes feed screw mechanisms 21AL and 21AR, and adjustment blocks 21BL and 21BR. The In the present embodiment, the moving body moved by the table moving mechanism 20 includes the X-axis table 2, the cylinder 20 </ b> A, the work W, and the gravity center position adjusting mechanism 21.

  The feed screw mechanisms 21AL and 21AR are mechanisms for moving the adjustment blocks 21BL and 21BR in the Z-axis direction. For example, the feed screw mechanisms 21AL and 21AR move the adjustment blocks 21BL and 21BR in the Z-axis direction by rotating a feed screw that engages with a spiral thread groove formed in the adjustment blocks 21BL and 21BR. . The feed screw mechanisms 21AL and 21AR may be manually operated, or may be automatically operated by a driving mechanism (not shown) such as a hydraulic actuator.

  The adjustment blocks 21BL and 21BR are weights for adjusting the position of the center of gravity GC of the moving body. In the present embodiment, the weight and shape of the adjustment block 21BL are the same as the weight and shape of the adjustment block 21BR. The feed screw mechanisms 21AL and 21AR simultaneously move the adjustment blocks 21BL and 21BR so that the position of the adjustment block 21BL and the position of the adjustment block 21BR are symmetric with respect to the vertical plane including the longitudinal axis of the cylinder 20A. Move. However, the present invention is not limited to this. If the position of the center of gravity GC of the moving body moved by the table moving mechanism 20 can be appropriately adjusted, at least one of the weight and shape of the adjustment block 21BL is different from the weight and shape of the adjustment block 21BR. May be. Further, the feed screw mechanisms 21AL and 21AR may individually change the positions of the adjustment blocks 21BL and 21BR as long as the position of the center of gravity GC of the moving body moved by the table moving mechanism 20 can be appropriately adjusted. .

  In the present embodiment, the gravity center position adjustment mechanism 21 moves the position of the gravity center GC of the moving body vertically downward by moving the adjustment blocks 21BL and 21BR in the −Z direction. Conversely, the center-of-gravity position adjustment mechanism 21 moves the position of the center of gravity GC of the moving body vertically upward by moving the adjustment blocks 21BL and 21BR in the + Z direction. However, the present invention is not limited to this. The center-of-gravity position adjusting mechanism 21 not only moves the position of the center of gravity GC of the moving body in the Z-axis direction but also moves in the X-axis direction and the Y-axis direction by appropriately moving the positions of the adjustment blocks 21BL and 21BR. You may let them.

  In this way, the center-of-gravity position adjusting mechanism 21 brings the position of the center of gravity GC of the moving body close to or coincides with the action line LA (see FIG. 5) of the driving force by the table moving mechanism 20. Alternatively, the center-of-gravity position adjusting mechanism 21 brings the position of the center of gravity GC of the moving body close to or coincides with the point of action PA (see FIG. 5) of the driving force by the table moving mechanism 20.

  As a result, the center-of-gravity position adjusting mechanism 21 can suppress or prevent the generation of a rotational moment (including a pitching moment and a yawing moment) when the X-axis table 2 is moved. In particular, the center-of-gravity position adjusting mechanism 21 can suppress or prevent the generation of a pitching moment when the X-axis table 2 is accelerated or decelerated. The shorter the distance between the position of the center of gravity GC of the moving body and the action line LA, the smaller the rotational moment. Also, if the position of the center of gravity GC of the moving body is on the action line LA, no rotational moment is generated. It is.

  Here, the adjustment of the gravity center position of the moving body by the gravity center position adjustment mechanism 21 will be described in more detail with reference to FIG. FIGS. 6A1, 6 </ b> B <b> 1, and 6 </ b> C <b> 1 are respectively elevational sectional views of the main body bed 1 and the X-axis table 2, and correspond to FIG. 4. 6A2, FIG. 6B2, and FIG. 6C2 are side sectional views of the main body bed 1 and the X-axis table 2, and correspond to FIG. 5. 6A1 corresponds to FIG. 6A2, FIG. 6B1 corresponds to FIG. 6B2, and FIG. 6C1 corresponds to FIG. 6C2.

  6 (A1) and 6 (A2) show a state when the adjustment blocks 21BL and 21BR are moved near the upper end of the adjustable range, and the position of the center of gravity GC of the moving body is within the work W. Indicates a certain state.

  FIGS. 6B1 and 6B2 show a state when the adjustment blocks 21BL and 21BR are moved to the vicinity of the center of the adjustable range, and the position of the center of gravity GC of the moving body is the X-axis table. 2 shows the state inside.

  Further, FIGS. 6C1 and 6C2 show a state when the adjustment blocks 21BL and 21BR are moved to the vicinity of the lower end of the adjustable range, and the position of the center of gravity GC of the moving body is that of the cylinder 20A. The state which exists on the longitudinal axis, ie, the action line LA of the driving force by the table moving mechanism 20, is shown.

  Thus, the center-of-gravity position adjustment mechanism 21 drives the position of the center of gravity GC of the moving body by the table moving mechanism 20 by appropriately adjusting the positions of the adjustment blocks 21BL and 21BR by the feed screw mechanisms 21AL and 21AR. The force action line LA or the action point PA can be brought close to or coincident with each other.

Next, an example of a method of determining the positions of the adjustment blocks 21BL and 21BR in the gravity center position adjustment mechanism 21 will be described with reference to FIG. Incidentally, the work W is a rectangular parallelepiped having a height a and the weight M _1. Further, X-axis table 2 (top plate portion 2A, the guide rail 2 BL, not shown in 2BR (FIG.), And the side plate portion 2CL, including 2CR.) Has a weight _{M 2,} the top plate portion 2A Has a height b. The cylinder 20A is a rectangular parallelepiped symmetric with respect to a longitudinal axis extending in a direction parallel to the X axis, and has a height c. That is, the longitudinal axis of the cylinder 20 </ b> A is located at a distance c / 2 from the lower surface of the X-axis table 2. Each of the adjustment blocks 21BL and 21BR is a rectangular parallelepiped that is symmetric with respect to a longitudinal axis extending in a direction parallel to the X axis, and is arranged to be symmetric with respect to a vertical plane including the longitudinal axis of the cylinder 20A. The adjustment block 21BL, 21BR has a total weight _{M 3.} That is, the adjustment block 21BL, 21BR, respectively, has a weight _M 3/2. Further, the center of gravity of the workpiece W, the center of gravity of the X-axis table 2, and the combined center of gravity of the adjustment block 21BL and the adjustment block 21BR are all on a vertical line passing through the center of gravity of the cylinder 20A.

  Under the above conditions, when the position of the center of gravity GC of the moving body coincides with the position of the center of gravity of the cylinder 20A, the respective centers of gravity GCL, GCR of the adjustment blocks 21BL, 21BR and the lower surface of the X-axis table 2 The distance h between them is derived by the following calculation formula (1) based on a known formula for obtaining the position of the center of gravity of the object.

入力装置（図示せず。）を通じてワークＷの重量Ｍ_１及び高さａが入力されると、平面研削盤１００の制御装置９は、既知の値である、Ｘ軸テーブル２の重量Ｍ_２及び高さｂと、シリンダ２０Ａの高さｃと、調整用ブロック２１ＢＬ、２１ＢＲの合計重量Ｍ_３とに基づいて、距離ｈを算出する。

When the weight M ₁ and the height a of the workpiece W are input through an input device (not shown), the control device 9 of the surface grinding machine 100 determines the weight M ₂ of the X-axis table 2 and the known values. and height b, based the height c of the cylinder 20A, the adjustment block 21bL, to the total weight _{M 3} of 21BR, calculates the distance h.

  Thereafter, the control device 9 displays the calculated value of the distance h on a display device (not shown), and the operator manually positions the adjustment blocks 21BL and 21BR using the feed screw mechanisms 21AL and 21AR. Allow adjustment.

  Alternatively, the control device 9 automatically operates the feed screw mechanisms 21AL and 21AR based on the calculated value of the distance h so that the center of gravity GCL and GCR of the adjustment blocks 21BL and 21BR and the lower surface of the X-axis table 2 The distance between is set to the distance h.

  In this way, the surface grinding machine 100 can match the position of the center of gravity GC of the moving body with the position of the center of gravity of the cylinder 20A.

  In addition, the control apparatus 9 prepared the above calculation formulas separately for every shape of the workpiece | work W, and selected the appropriate calculation formula according to the shape of the workpiece | work W, ie, according to the operator's input. The distance h may be derived above. Further, the control device 9 may derive the distance h using a calculation formula that takes into account the length and width of the workpiece W.

  Next, the relationship between the speed and acceleration of the moving body and the pitching angle will be described based on the actual measurement data with reference to FIG. FIG. 8 is a diagram illustrating the relationship between the speed and acceleration of the moving body and the pitching angle when the X-axis table 2 in a state where the workpiece W is not supported is reciprocated in the X-axis direction. In FIG. 8, the moving body moved by the table moving mechanism 20 includes the X-axis table 2, the cylinder 20 </ b> A, and the gravity center position adjusting mechanism 21. In addition, the center of gravity of the moving body exists above the action line of the driving force by the table moving mechanism 20, and the moving body is likely to generate a pitching moment.

  In FIG. 8, a time axis is arranged on the horizontal axis, an axis related to speed and acceleration is arranged on the left vertical axis, and an axis related to the pitching angle is arranged on the left vertical axis. In FIG. 8, the transition indicated by the dotted line represents the transition of the speed, the transition indicated by the solid line represents the transition of acceleration, and the transition indicated by the broken line represents the transition of the pitching angle. Further, as shown in FIG. 5, the speed is a positive value when the X-axis table 2 is moved in the + X direction and a negative value when the X-axis table 2 is moved in the -X direction. In FIG. 5, the pitching angle in the initial state of the table in FIG. 5 is 0 degree, the angle that increases clockwise with respect to the center of gravity GC of the moving body is a positive value, and the angle that increases counterclockwise is a negative value. .

  As shown in FIG. 8, when the moving body accelerates in the + X direction, it generates a pitching angle (negative value) corresponding to the magnitude of the acceleration (positive value). The moving body moves at a constant speed of about 580 [mm / sec] (about 35 [m / min]), then decelerates and further accelerates in the −X direction (negative value). ) To produce a pitching angle (positive value) according to the magnitude of.

  Thus, when the center of gravity of the moving body is not on the line of driving force, the pitching angle of the moving body tends to increase as the magnitude of acceleration of the moving body increases, and the increasing direction is the acceleration direction. The direction is reversed.

  Further, the relationship between the speed and acceleration of the moving body and the pitching angle when the X-axis table 2 with the workpiece W supported is reciprocated shows the same tendency as described above, and when the workpiece W is not supported. Compared with, the pitching angle becomes larger.

  Next, referring to FIG. 9, the relationship between the distance between the position of the center of gravity of the moving body and the line of action of the driving force (hereinafter referred to as “center of gravity distance”) and the pitching angle of the moving body is simulated. It demonstrates based on a result. FIG. 9 is a diagram showing the temporal transition of the pitching angle of the moving body when the X-axis table 2 is reciprocated in the X-axis direction as in the case of FIG. In FIG. 9, the moving body moved by the table moving mechanism 20 includes the X-axis table 2, the cylinder 20 </ b> A, and the gravity center position adjusting mechanism 21, as in the case of FIG. 8.

  In FIG. 9, the time axis is arranged on the horizontal axis, and the axis related to the pitching angle is arranged on the vertical axis. In FIG. 9, the transition indicated by the dotted line represents the transition when the center-of-gravity distance is 200 [mm] (for example, corresponding to the states shown in FIGS. 6A1 and 6A2), and is indicated by a broken line. The transition shown represents the transition when the center-of-gravity distance is 120 [mm] (for example, corresponding to the states shown in FIGS. 6B1 and 6B2), and the transition indicated by the solid line has a center-of-gravity distance of 0. In the case of [mm] (for example, corresponding to the states shown in FIGS. 6C1 and 6C2), the transition is represented.

  As shown in FIG. 9, the maximum value of the change in the pitching angle is D1 [μrad] when the centroid distance is 200 [mm], whereas D2 [μrad] when the centroid distance is 120 [mm]. μrad]. Further, when the center-of-gravity distance is 0 [mm], that is, when the position of the center of gravity GC of the moving body is on the line of driving force, the distance decreases to 0 [μrad].

  Therefore, the center-of-gravity position adjusting mechanism 21 suppresses or prevents the generation of the pitching moment by decreasing the center-of-gravity distance, that is, by bringing the position of the center of gravity GC of the moving body closer to or coincident with the line of action of the driving force. Can do.

  With the above configuration, the surface grinding machine 100 including the center-of-gravity position adjusting mechanism 21 grinds the workpiece W by suppressing or preventing the tilt of the X-axis table 2 when the X-axis table 2 is reciprocated in the X-axis direction. Accuracy can be increased.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, the table moving mechanism 20 is configured by a hydraulic actuator including the cylinder 20A, but may be configured by other moving mechanisms such as a ball screw mechanism and a linear motor.

  In the above-described embodiment, the center-of-gravity position adjustment mechanism 21 employs a feed screw mechanism as a moving mechanism for moving the adjustment blocks 21BL and 21BR up and down, but other mechanisms may be employed.

  Moreover, in the above-mentioned Example, although a rectangular parallelepiped is employ | adopted as a shape of the blocks 21BL and 21BR for adjustment, arbitrary shapes may be employ | adopted. The adjustment blocks 21BL and 21BR are attached to the feed screw mechanisms 21AL and 21AR as movement mechanisms so as not to be detachable, but some or all of them may be detachably attached to the movement mechanism.

  In the above-described embodiments, weight-invariant members are employed as the adjustment blocks 21BL and 21BR. However, for example, weight-variable members such as containers for storing fluids may be employed. In this case, the weights of the adjustment blocks 21BL and 21BR can be adjusted by changing the amount of fluid to be stored.

  In the above-described embodiment, the adjustment blocks 21BL and 21BR are arranged one by one on both sides of the X-axis table 2, but one is arranged on each side of the cylinder 20A at the lower part of the X-axis table 2. Alternatively, only one may be arranged vertically below the cylinder 20A. Further, the number of adjustment blocks may be one or three or more.

  DESCRIPTION OF SYMBOLS 1 ... Main body bed 1AL, 1AR ... Rail groove 2 ... X-axis table 2A ... Top plate part 2BL, 2BR ... Guide rail 2CL, 2CR ... Side plate part 3 ... Horizontal axis Grinding wheel column 4 ... Horizontal axis grinding wheel head 5 ... Grinding wheel head rotation motor 6 ... Grinding wheel head vertical feed motor 7 ... Grinding wheel head left / right feeding motor 8 ... Table drive motor 9 ..Control device 20 ... Table moving mechanism 20A ... Cylinder 20As ... Cylinder space 20As1 ... First cylinder space 20As2 ... Second cylinder space 20BF ... First shaft 20BB ... No. Biaxial 20C ... Piston 21 ... Center of gravity position adjusting mechanism 21AL, 21AR ... Feed screw mechanism 21BL, 21BR ... Adjusting block 40 ... Whetstone shaft 41 ... grinding wheel 100 ... surface grinding machine GC ··· center of gravity PA ··· action point LA ··· line of action W ··· work

Claims (3)

A surface grinding machine including a movable table for supporting an object to be ground,
A table moving mechanism for moving the movable table;
A center-of-gravity position adjustment mechanism that adjusts the center-of-gravity position of a moving body that is moved by the table moving mechanism
The movable body includes the object to be ground, the movable table, and the gravity center position adjusting mechanism.
Surface grinder characterized by that. The center-of-gravity position adjustment mechanism brings the position of the center of gravity of the movable body close to or coincides with the line of action of the driving force by the table movement mechanism;
The surface grinding machine according to claim 1, wherein: The center-of-gravity position adjusting mechanism brings the position of the center of gravity of the movable body close to or coincides with the point of application of the driving force by the table moving mechanism;
The surface grinding machine according to claim 1 or 2, characterized in that

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