JP2013226634A - Surface grinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface grinder capable of damping vibration at an early stage, the vibration of a movable table that is caused with the acceleration and deceleration of the movable table.SOLUTION: A surface grinder 100 moves an X-axis table 2 using a table-moving mechanism 20 capable of adjusting a flow rate and flow direction of a hydraulic fluid. The surface grinder includes: a control device 9 for controlling the movement of the X-axis table 2 by using the position or the velocity of the X-axis table 2 as an object for control; and a main controller 9A for controlling the flow rate and flow direction of the hydraulic fluid according to a table position command or a table velocity command from the control device 9 and the acceleration of the X-axis table 2.

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, an electro-hydraulic conversion type driving device that reciprocally moves a movable table using a closed circuit hydraulic system including a bidirectional hydraulic pump and a hydraulic cylinder is known (for example, see Patent Document 1).

  This device controls the rotational speed of an electric servo motor that drives a bidirectional hydraulic pump based on the output of a tachometer that detects the feed speed of the movable table. With this configuration, the feed rate of the movable table can be controlled without the need to provide a valve for controlling the flow of hydraulic oil as in an open circuit hydraulic system, and energy efficiency can be improved.

JP-A-62-184206

  However, the electro-hydraulic conversion drive device of Patent Document 1 controls the rotation speed of the electric servo motor based only on the command speed of the movable table. Therefore, deterioration of controllability due to the vibration of the movable table caused by the acceleration / deceleration of the movable table cannot be prevented. In particular, the variable capacity hydraulic system has a lower vibration loss than the constant capacity hydraulic system because the pressure loss in the hydraulic circuit is small.

  In view of the above-described points, an object of the present invention is to provide a surface grinder that can quickly attenuate the vibration of the movable table caused by the acceleration / deceleration of the movable table.

  To achieve the above object, a surface grinder according to an embodiment of the present invention is a surface grinder that moves a movable table using a hydraulic system capable of adjusting the flow rate and flow direction of a working fluid, A control device that controls movement of the movable table using the position or speed of the movable table as a control target, and a flow rate of the working fluid according to a table position command or table speed command from the control device and acceleration of the movable table And a main controller for controlling the flow direction.

  With the above-described means, the present invention can provide a surface grinder that can quickly attenuate the vibration of the movable table caused by the acceleration / deceleration of the movable table.

It is a side view of the surface grinding machine which concerns on the Example of this invention. It is a top view of the surface grinder of FIG. It is a front sectional view of a table moving mechanism. It is a sectional side view of a table moving mechanism. It is the schematic which shows the structural example of a table moving mechanism. It is a figure which shows the flow of control when the surface grinder which mounts the table moving mechanism of FIG. 5 moves an X-axis table. It is FIG. (1) which shows the structural example of a main controller. FIG. 3 is a diagram (part 2) illustrating a configuration example of a main controller; FIG. 6 is a diagram (part 3) illustrating a configuration example of a main controller; FIG. 6 is a diagram (part 4) illustrating a configuration example of a main controller; It is a figure which shows the time transition of the table position of the X-axis table, table speed, and table acceleration. It is the schematic which shows another structural example of a table moving mechanism. It is a figure which shows the flow of control when the surface grinder which mounts the table moving mechanism of FIG. 12 moves an X-axis table. It is the schematic which shows another structural example of a table moving mechanism. It is the schematic which shows another structural example of a table moving mechanism. It is a figure which shows the flow of control when the surface grinder which mounts the table moving mechanism of FIG. 15 moves an X-axis table. It is the schematic which shows another structural example of a table moving mechanism. It is a figure which shows the flow of control when the surface grinder which mounts the table moving mechanism of FIG. 17 moves an X-axis table.

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

  FIG. 1 is a side 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 movable table that can slide on the main body bed 1 in the X-axis direction, and supports the workpiece (workpiece) W 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 grinding wheel head 4 is a grinding wheel head having a grinding wheel shaft 40. 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. For example, a 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 a 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 grinding wheel head left / right feeding motor 7 is a 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 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 driving motor 8 is a motor that drives a table moving mechanism for moving the X-axis table 2 in the X-axis direction. In the present embodiment, the table driving motor 8 is a servo motor for rotating a bidirectional hydraulic pump constituting a table moving mechanism that is a closed circuit hydraulic system.

  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. The control device 9 may perform grinding by bringing the grinding wheel 41 into contact with the workpiece W when moving the X-axis table in the −X direction.

  Next, the table moving mechanism 20 will be described with reference to FIGS. 3 is a front sectional view of the vertical plane including the alternate long and short dash line in each of FIGS. 1 and 2 as viewed from the direction indicated by arrow III, and FIG. 4 is the alternate long and two short dashes line in each of FIGS. It is the sectional side view which looked at the vertical plane containing No. from the direction shown by arrow IV. FIG. 5 is a schematic diagram illustrating a configuration example of the table moving mechanism 20. In addition, in FIG. 5, illustration of the main body bed 1 is abbreviate | omitted for clarity.

  As shown in FIG. 5, 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 21, a piston 22, a first shaft 23F, a second shaft 23B, and both. It is composed of a closed circuit hydraulic system including a directional hydraulic pump 24.

  The cylinder 21 is fixed to the lower surface of the X-axis table 2 and moves along the X-axis table 2 on the main body bed 1 in the X-axis direction. The cylinder 21 includes a pressure chamber 21S (see FIG. 4) inside, and receives the piston 22 in the pressure chamber 21S so that the piston 22 can slide relative to the inner wall of the pressure chamber 21S. As shown in FIG. 4, the pressure chamber 21 </ b> S is separated into a first pressure chamber 21 </ b> SF and a second pressure chamber 21 </ b> SB by the piston 22.

  The first shaft 23F is a cylindrical member having one end fixed to the + X side surface of the piston 22 and the other end fixed to an external stationary object 23Fa. Similarly, the second shaft 23B is a cylindrical member whose one end is fixed to the −X side surface of the piston 22 and the other end is fixed to the external stationary object 23Ba. The stationary objects 23Fa and 23Ba may be any object that can hold the cylinder 21, the first shaft 23F, and the second shaft 23B stationary when the X-axis table 2 is moved. May be.

  Piston 22 is a disk member accommodated in pressure chamber 21S so that it can move relative to the inner wall of pressure chamber 21S within pressure chamber 21S of cylinder 21. The piston 22 has a + X side surface connected to the first shaft 23F and a −X side surface connected to the first shaft 23F.

  With such a configuration, the cylinder 21 can reciprocate with respect to the main body bed 1 together with the X-axis table 2, whereas the first shaft 23F, the second shaft 23B, and the piston 22 are attached to the main body bed 1. It arrange | positions so that it may stand still with respect to it.

  As shown in FIG. 3, the X-axis table 2 includes two V-shaped guide rails 2BL and 2BR that protrude in the −Z direction from the lower surface thereof. Further, the X-axis table 2 is supported by the main body bed 1 so as to reciprocate in the X-axis direction on the main body bed 1 using a hydrostatic bearing mechanism, a dynamic pressure bearing mechanism, or a combination thereof or other bearing mechanisms. Is done. Note that the shape of the guide rail is not necessarily V-shaped.

  The reciprocating movement of the X-axis table 2 in the X-axis direction is controlled by a bidirectional hydraulic pump 24 driven by the table driving motor 8. Specifically, as shown in FIGS. 4 and 5, when the X-axis table 2 is moved in the direction indicated by the arrow AR (−X direction), the working fluid discharged from the second port 24 </ b> B of the bidirectional hydraulic pump 24. As shown by the dotted line, the hydraulic oil flows through the second shaft 23B and flows into the second pressure chamber 21SB of the cylinder 21. On the other hand, the hydraulic oil in the first pressure chamber 21SF of the cylinder 21 reaches the first port 24F of the bidirectional hydraulic pump 24 through the first shaft 23F. As a result, the volume of the second pressure chamber 21SB increases, the volume of the first pressure chamber 21SF decreases, and the X-axis table 2 is moved in the −X direction.

  Although illustration is omitted, when the X-axis table 2 is moved in the + X direction, the hydraulic oil discharged from the first port 24F of the bidirectional hydraulic pump 24 passes through the first shaft 23F and the first pressure in the cylinder 21. It flows into the chamber 21SF. On the other hand, the hydraulic oil in the second pressure chamber 21SB of the cylinder 21 reaches the second port 24B of the bidirectional hydraulic pump 24 through the second shaft 23B. As a result, the volume of the first pressure chamber 21SF increases, the volume of the second pressure chamber 21SB decreases, and the X-axis table 2 is moved in the + X direction.

  As shown in FIG. 5, the bidirectional hydraulic pump 24 is rotationally driven by the table driving motor 8, and the hydraulic fluid having a flow rate corresponding to the rotational direction and the rotational speed of the table driving motor 8 is supplied to the first port 24 </ b> F or the second. Discharge from port 24B.

  The table driving motor 8 is driven according to the current supplied by the motor driver 8A. The motor driver 8A supplies a current to the table driving motor 8 in accordance with a flow rate command (for example, a motor rotation number command or a torque command) from the main controller 9A of the control device 9.

  The main controller 9A controls the rotational speed of the bidirectional hydraulic pump 24. For example, the main controller 9A generates a motor rotation speed command or a torque command based on various command values from the control device 9 and various sensor outputs from various sensors. Specifically, the various command values are command values generated by the control device 9 in response to an operator's input or the like, and include a table position command, a table speed command, a table acceleration command, a table drive motor rotational speed command (motor Speed command). The various sensor outputs include outputs from the displacement sensor 30, the first cylinder pressure sensor 31F, the second cylinder pressure sensor 31B, the rotation angle sensor 32, and the like.

  The displacement sensor 30 is a displacement sensor that detects the displacement of the X-axis table 2. For example, the displacement sensor 30 detects a linear displacement with respect to a predetermined reference position of the X-axis table 2, and outputs the detection result to the control device 9. In this embodiment, for example, a linear scale is used as the displacement sensor 30.

  The first cylinder pressure sensor 31F is a sensor that detects the pressure of the first pressure chamber 21SF in the cylinder 21, for example, in a pipe line that connects the first shaft 23F and the first port 24F of the bidirectional hydraulic pump 24. The pressure of the hydraulic oil is detected, and the detection result is output to the control device 9.

  Similarly, the second cylinder pressure sensor 31B is a sensor that detects the pressure of the second pressure chamber 21SB in the cylinder 21, and is, for example, a pipe that connects the second shaft 23B and the second port 24B of the bidirectional hydraulic pump 24. The pressure of hydraulic oil in the road is detected, and the detection result is output to the control device 9.

  The first cylinder pressure sensor 31F and the second cylinder pressure sensor 31B may be attached to the first pressure chamber 21SF and the second pressure chamber 21SB, or may be attached to the first shaft 23F and the second shaft 23B. .

  The rotation angle sensor 32 is a sensor that detects the rotation of the table drive motor 8. For example, the rotation angle sensor 32 detects the rotation direction and the rotation angle of the table drive motor 8 and outputs the detection result to the control device 9. In this embodiment, for example, a resolver is used as the rotation angle sensor 32.

  FIG. 6 is a diagram showing a flow of control when the surface grinding machine 100 moves the X-axis table 2. As shown in FIG. 6, the main controller 9 </ b> A acquires various command values including at least one of a table position command, a table speed command, a table acceleration command, and a motor speed command from the control device 9. And main controller 9A acquires various sensor outputs as needed. The various sensor outputs include at least one of a table position signal output from the displacement sensor 30, a cylinder pressure signal output from the cylinder pressure sensors 31F and 31B, and a motor rotation angle signal output from the rotation angle sensor 32.

  Thereafter, main controller 9A generates a motor rotation speed command or torque command based on the acquired various command values and various sensor outputs, and outputs the generated motor rotation speed command or torque command to motor driver 8A.

  Thereafter, the motor driver 8A supplies a current to the table driving motor 8 in accordance with a motor rotational speed command or a torque command from the main controller 9A.

  Here, the transfer function v / Q from the flow rate Q of the hydraulic oil discharged from the bidirectional hydraulic pump 24 to the table speed v of the X-axis table 2 in the closed circuit hydraulic system constituting the table moving mechanism 20 will be described.

  When the center of the X-axis table 2 and the center of the piston 22 are on the same vertical line, the transfer function v / Q is expressed by the following equation (1).

ここで、ｓはラプラス演算子を表し、Ａ_ｃｙｌはピストン２２の受圧面積を表し、Ｖ_ｃｙｌは圧力室２１Ｓの容積を表し、ＭはＸ軸テーブル２の質量を表し、ＢはＸ軸テーブル２の粘性摩擦係数を表し、Ｋ_oilは作動油の体積弾性係数を表す。

Here, s represents a Laplace operator, A _cyl represents the pressure receiving area of the piston 22, V _cyl represents the volume of the pressure chamber 21S, M represents the mass of the X-axis table 2, and B represents the X-axis table 2 The viscous friction coefficient of the hydraulic _oil is represented by K _oil , and the bulk modulus of the hydraulic _oil is represented by K _oil .

Flow rate Q is proportional to the motor rotation speed omega _m of the table drive motor 8, if put the displacement volume per unit rotation speed and W _P, the transfer function from the motor rotation speed omega _m up table velocity v is less (2)

ここで、ω_ｎ、ζ_ｎは、それぞれ、Ｘ軸テーブル２の固有振動数、減衰係数であり、以下の式（３）、（４）で表される。

Here, ω _n and ζ _n are the natural frequency and damping coefficient of the X-axis table 2, respectively, and are expressed by the following equations (3) and (4).

また、Ｋ_ＨＳＴは、閉回路油圧システムによるゲインであり、以下の式（５）で表される。

K _HST is a gain obtained by the closed circuit hydraulic system and is expressed by the following equation (5).

なお、固有振動数ω_ｎは、ζ_ｎ＝０の場合に、Ｘ軸テーブル２の加減速時に生じるＸ軸テーブル２の固有振動数を意味する。また、減衰係数ζ_ｎは、Ｘ軸テーブル２の振動の減衰性を表す係数であり、ζ_ｎ＜１の場合にあっては、値が１に近いほど振動が短時間で減衰することを表す。

The natural frequency ω _n means the natural frequency of the X-axis table 2 generated when the X-axis table 2 is accelerated / decelerated when ζ _n = 0. Further, the damping coefficient ζ _n is a coefficient representing the damping property of the vibration of the X-axis table 2, and in the case of ζ _n <1, it represents that the vibration is damped in a shorter time as the value is closer to 1. .

Further, when feedback of the speed and acceleration of the X-axis table 2 is performed, the transfer function from the speed command v _dir to the table speed v is expressed by the following expression (6) based on the above expression (2).

ここで、ω_ｃ、ζ_ｃは、それぞれ、Ｘ軸テーブル２の速度及び加速度のフィードバックが行われる場合のＸ軸テーブル２の制御固有振動数、制御減衰係数であり、以下の式（７）、（８）で表される。

Here, ω _c and ζ _c are a control natural frequency and a control damping coefficient of the X-axis table 2 when the speed and acceleration of the X-axis table 2 are fed back, respectively, and the following equations (7), It is represented by (8).

なお、Ｋ_ｖ、Ｋ_ａは、それぞれ、速度フィードバックゲイン、加速度フィードバックゲインであり、以下の式（９）、（１０）で表される。

K _v and K _a are a speed feedback gain and an acceleration feedback gain, respectively, and are expressed by the following equations (9) and (10).

上述の関係は、所望の制御減衰係数ζ_ｃの値に応じて加速度フィードバックゲインＫ_ａを決定できること、すなわち、加速度フィードバックゲインＫ_ａを調節することによって所望の制御減衰係数ζ_ｃの値を実現できることを意味する。なお、制御減衰係数ζ_ｃの値は、例えば、０．７（＝１／√２）〜１．０の間の値が選択されることが望ましい。

The above relationship, it can determine the acceleration feedback gain K _a according to the value of the desired control damping coefficients zeta _c, i.e., can be realized the value of the desired control damping coefficients zeta _c by adjusting the acceleration feedback gain K _a Means. For example, a value between 0.7 (= 1 / √2) and 1.0 is preferably selected as the value of the control damping coefficient ζ _c .

  Next, a configuration example of the main controller 9A will be described with reference to FIG.

  In the configuration example of FIG. 7, the main controller 9A acquires a table position command, a table speed command, and a table position signal, and outputs a motor rotation speed command or a torque command to the motor driver 8A.

Specifically, the main controller 9A first subtracts a value PL represented by a table position signal from the displacement sensor 30 from a value represented by a table position command from the control device 9 according to a proportional control law, and obtains a predetermined gain. multiplied by K _p deriving a first control value V1 with. The main controller 9A may use a proportional-integral control law instead of the proportional control law. Specifically, the main controller 9A adds a value obtained by subtracting the value PL from the value represented by the table position command and a value obtained by dividing the integral value of the subtracted value by a predetermined time constant, and then adds a predetermined value. The first control value V1 may be derived by multiplying the gain Kp.

Thereafter, the main controller 9A _adds a speed feedforward value VFF _obtained by multiplying the value represented by the table speed command from the control device 9 by the speed feedforward gain _Kvff and the first control value V1. Then, the main controller 9A from the value after addition (V1 + VFF), by subtracting the speed feedback value VFB obtained by multiplying the velocity feedback gain K _v table position signal to a value represented by the table speed signal obtained by the pseudo-differential The second control value V2 is derived.

Thereafter, the main controller 9A obtains an acceleration feedback gain from the second control value V2 to a value represented by a table acceleration signal obtained by pseudo-differentiating the table speed signal, that is, obtained by second-order pseudo-differentiating the table position signal. by subtracting the acceleration feedback value AFB multiplied by K _a, derive motor rotational speed command or torque command.

The main controller 9A adds an acceleration feedforward value AFF (not shown) obtained by multiplying the value represented by the table acceleration command from the control device 9 by the speed feedforward gain _Kaff and the second control value V2. Then, the motor feedback command or torque command may be derived by subtracting the acceleration feedback value AFB. The main controller 9A may omit the calculation of the speed feedback value VFB and the subtraction of the speed feedback value VFB from the total value of the first control value V1 and the speed feedforward value VFF.

As described above, the main controller 9A shown in FIG. 7 adjusts the acceleration feedback gain K _a under the control model having the transfer function expressed by the equation (6), to thereby obtain a desired control damping coefficient ζ _c. Can be realized. As a result, the surface grinding machine 100 including the main controller 9A shown in FIG. 7 can quickly attenuate the vibration of the X-axis table 2 that occurs when the X-axis table 2 is accelerated or decelerated.

  Next, another configuration example of the main controller 9A will be described with reference to FIG.

  In the configuration example of FIG. 8, the main controller 9A acquires the first cylinder pressure signal and the second cylinder pressure signal from the first cylinder pressure sensor 31F and the second cylinder pressure sensor 31B instead of the table position signal. This is different from the case of FIG. That is, it differs from the control of FIG. 7 in which the table acceleration signal obtained by second-order differentiation of the table position signal is fed back in that the table acceleration signal derived from the differential pressure between the pressure chambers is fed back.

  Further, the main controller 9A differs from the control of FIG. 7 in that the motor rotational speed command or the torque command is derived based on the speed feedforward value VFF without deriving the first control value V1 based on the table position command. .

Specifically, the main controller 9A first subtracts the acceleration feedback value AFB from the speed feedforward value VFF _obtained by multiplying the value represented by the table speed command from the control device 9 by the speed feedforward gain _Kvff , Deriving motor rotation speed command or torque command.

  In the control shown in FIG. 8, the main controller 9A derives the acceleration feedback value AFB based on the first cylinder pressure signal and the second cylinder pressure signal.

  Specifically, the main controller 9A derives the difference between the first cylinder pressure signal and the second cylinder pressure signal, and applies a low-pass filter and a high-pass filter to the derived value. The low-pass filter is a functional element for removing noise included in the difference, and the high-pass filter is a functional element for removing the influence of the frictional force included in the difference. The signal after applying the low-pass filter and the high-pass filter has, for example, a frequency that is about 1/3 to 5 times the natural frequency of the X-axis table 2.

Thereafter, the main controller 9A multiplies the differential pressure signal by A _cyl / M to obtain a table acceleration signal. That is, the main controller 9A multiplies the value represented by the differential pressure signal by the pressure receiving area A _cyl of the piston 22 based on the equation of motion to derive the driving force by the bidirectional hydraulic pump 24, and calculates the driving force by the X-axis table. Divide by the mass M of 2 to derive the acceleration of the X-axis table 2. It should be noted that the mass M used when the velocity feedback gain is determined by the equation (9), the acceleration feedback gain is determined by the equation (10), and the acceleration of the X-axis table 2 is derived from the differential pressure signal, May vary depending on mass. In this case, instead of the actual mass, the nominal mass may be used as the value of the mass M. It is desirable to use the maximum mass of the workpiece W that can be mounted on the X-axis table 2 as the nominal mass.

Thereafter, the main controller 9A derives acceleration feedback value AFB by multiplying the acceleration feedback gain K _a to the value table acceleration signal represents.

In the control shown in FIG. 8, the main controller 9A also uses an acceleration feedforward value AFF (not shown) obtained by multiplying the value represented by the table acceleration command from the control device 9 by the speed feedforward gain _Kaff . After adding the speed feedforward value VFF, the motor feedback command AFB may be derived by subtracting the acceleration feedback value AFB.

  Further, the main controller 9A shown in FIG. 8 does not acquire the cylinder pressure signal from each of the first cylinder pressure sensor 31F and the second cylinder pressure sensor 31B, but instead of the first pressure chamber 21SF and the second pressure chamber 21SB. A differential pressure signal may be acquired from a differential pressure sensor (not shown) that detects a differential pressure therebetween.

Thus, the main controller 9A shown in FIG. 8, similarly to the case shown in FIG. 7, under the control model having a transfer function represented by the formula (6), by adjusting the acceleration feedback gain K _a The desired control damping coefficient ζ _c can be realized. As a result, the surface grinding machine 100 including the main controller 9A shown in FIG. 8 can quickly attenuate the vibration of the X-axis table 2 that occurs when the X-axis table 2 is accelerated or decelerated.

  Next, still another configuration example of the main controller 9A will be described with reference to FIG.

  9 differs from the case of FIG. 7 in that the main controller 9A acquires a table speed signal from a table speed sensor (not shown) such as a tachometer instead of the table position signal. . That is, it differs from the control of FIG. 7 in which the table acceleration signal obtained by second-order differentiation of the table position signal is fed back in that the table acceleration signal obtained by first-order differentiation of the table speed signal is fed back.

  Further, the main controller 9A differs from the control of FIG. 7 in that the motor rotational speed command or the torque command is derived based on the speed feedforward value VFF without deriving the first control value V1 based on the table position command. .

Specifically, the main controller 9A first derives a speed feedforward value VFF _obtained by multiplying the value represented by the table speed command from the control device 9 by the speed feedforward gain _Kvff .

Thereafter, the main controller 9A from the speed feedforward value VFF, by subtracting the speed feedback value VFB obtained by multiplying the velocity feedback gain K _v to the value table speed signal represents, derive a second control value V2.

Thereafter, the main controller 9A, from the second control value V2, by subtracting the acceleration feedback value AFB obtained by multiplying the acceleration feedback gain K _a to the value represented by the table acceleration signal obtained by first-order quasi-differentiation of the table speed signal Thus, the motor rotational speed command or torque command is derived.

Also in the control shown in FIG. 9, the main controller 9 _{</ b> A} has a value AFF (not shown) obtained by multiplying the value represented by the table acceleration command from the control device 9 by the speed feedforward gain K _aff , and the second control. The motor rotation speed command or torque command may be derived by adding the value V2 and subtracting the acceleration feedback value AFB. The main controller 9A may omit calculation of the speed feedback value VFB and subtraction of the speed feedback value VFB from the speed feedforward value VFF.

Thus, the main controller 9A shown in Figure 9, similarly to the case shown in FIG. 7, under the control model having a transfer function represented by the formula (6), by adjusting the acceleration feedback gain K _a The desired control damping coefficient ζ _c can be realized. As a result, the surface grinding machine 100 including the main controller 9A shown in FIG. 9 can quickly attenuate the vibration of the X-axis table 2 that occurs when the X-axis table 2 is accelerated or decelerated.

  Next, still another configuration example of the main controller 9A will be described with reference to FIG.

  In the configuration example of FIG. 10, the main controller 9A is different from the case of FIG. 7 in that it acquires a table acceleration signal from a table acceleration sensor (not shown) instead of the table position signal. That is, it differs from the control of FIG. 7 in which the table acceleration signal obtained by second-order differentiation of the table position signal is fed back in that the table acceleration signal obtained directly from the table acceleration sensor is fed back.

  Further, the main controller 9A differs from the control of FIG. 7 in that the motor rotational speed command or the torque command is derived based on the speed feedforward value VFF without deriving the first control value V1 based on the table position command. .

Specifically, the main controller 9A first derives a speed feedforward value VFF _obtained by multiplying the value represented by the table speed command from the control device 9 by the speed feedforward gain _Kvff .

  Thereafter, the main controller 9A subtracts the acceleration feedback value AFB from the speed feedforward value VFF to derive a motor rotation speed command or a torque command.

Also in the control shown in FIG. 10, the main controller 9 _{</ b> A} has an acceleration feedforward value AFF (not shown) obtained by multiplying the value represented by the table acceleration command from the control device 9 by the speed feedforward gain K _aff . After adding the speed feedforward value VFF, the motor feedback command AFB may be derived by subtracting the acceleration feedback value AFB.

Thus, the main controller 9A shown in FIG. 10, similarly to the case shown in FIG. 7, under the control model having a transfer function represented by the formula (6), by adjusting the acceleration feedback gain K _a The desired control damping coefficient ζ _c can be realized. As a result, the surface grinding machine 100 including the main controller 9A of FIG. 10 can attenuate the vibration of the X-axis table 2 that occurs when the X-axis table 2 is accelerated or decelerated at an early stage.

  The main controller 9A shown in FIGS. 8 to 10 cancels the difference between the actual table position value and the value represented by the table position command, or represents the actual table speed value and the table speed command. The motor rotational speed command or torque command may be derived so as to cancel the difference from the value. For example, the main controller 9A shown in FIGS. 8 to 10 speeds the first control signal V1 calculated based on the value represented by the table position command and the value PL represented by the table position signal, as in the case of FIG. You may make it add to feedforward value VFF.

  Moreover, although the structure of 9 A of main controllers in each of FIGS. 7-10 is comprised with the digital circuit for performing digital control, this invention is not limited to this. For example, the main controller 9A may be configured by an analog circuit including an operational amplifier or the like, an analog computer, or the like.

  Next, the vibration damping characteristics of the X-axis table 2 controlled by the main controller 9A will be described with reference to FIG. FIG. 11 is a diagram showing temporal transitions of the table position, table speed, and table acceleration of the X-axis table 2, and FIG. 11A shows the transition when the acceleration feedback value AFB is not used. (B) shows the transition when the acceleration feedback value AFB is used. Moreover, the time transition of the table position is common in FIG. 11 (A) and FIG. 11 (B).

  The hatched area in FIG. 11 represents the time from when the table acceleration value becomes less than a predetermined value and the table speed is settled until the table acceleration value becomes equal to or more than the predetermined value and the table speed fluctuates. Conversely, in the non-hatched area (white area) in FIG. 11, the table acceleration value becomes less than the predetermined value after the table acceleration value becomes equal to or greater than the predetermined value and the table speed becomes less than the predetermined value until the table speed is stabilized. Represents time. Hereinafter, the hatched area is referred to as a table speed stable period, and the non-hatched area (white area) is referred to as a table speed fluctuation period.

  As shown in FIG. 11, the table speed fluctuation period when the acceleration feedback value AFB is used (white area in FIG. 11B) is the table speed fluctuation period when the acceleration feedback value AFB is not used (FIG. 11A). ) Is shorter than the white area). Further, the table speed stable period when the acceleration feedback value AFB is used (hatched area in FIG. 11B) is the table speed stable period when the acceleration feedback value AFB is not used (hatched area in FIG. 11A). Longer than This means that the portion that can be used for grinding the workpiece W in one stroke of the X-axis table 2 becomes longer. Moreover, it means that the allowable maximum length in the X-axis direction of the workpiece W placed on the X-axis table 2 can be further increased. That is, it means that all of the grinding efficiency, energy efficiency, and acceptability of the workpiece are improved.

  With the above configuration, the surface grinding machine 100 including the main controller 9A attenuates the vibration of the X-axis table 2 caused by the acceleration / deceleration of the X-axis table 2 at an early stage, so that the grinding efficiency, energy efficiency, and processing The object acceptability can be improved.

Also, the operator of the surface grinder 100 with a master controller. 9A, by appropriately adjusting the acceleration feedback gain K _a, it is possible to shorten the settling time of the table velocity in the X-axis table 2.

Further, the operator, by adjusting the acceleration feedback gain K _a to approach the value of the control damping coefficients zeta _c to 1, reduced or that the table velocity in the X-axis table 2 overshoot the value of the speed command Can be prevented.

Note that a general closed circuit hydraulic system does not have a valve for controlling the flow of hydraulic oil and has a small pressure loss in the oil passage as compared with an open circuit hydraulic system, and therefore the vibration damping performance is likely to deteriorate. However, since the table moving mechanism 20 controlled by the main controller 9A can set the value of the control damping coefficient ζ _c to a desired value, it can overcome the disadvantages of such a general closed circuit hydraulic system. .

  Next, another embodiment of the table moving mechanism will be described with reference to FIGS. FIG. 12 is a schematic diagram illustrating a configuration example of the table moving mechanism 20V, and corresponds to FIG. FIG. 13 is a diagram showing a control flow when the surface grinding machine 100 on which the table moving mechanism 20V is mounted moves the X-axis table 2, and corresponds to FIG.

  The table moving mechanism 20V is an open circuit hydraulic system including a unidirectional hydraulic pump 24u, a directional control valve 25, a relief valve 26, and check valves 27 and 28, and the table moving mechanism including the bidirectional hydraulic pump 24 in FIG. Different from the mechanism 20. However, the table moving mechanism 20V is common to the table moving mechanism 20 of FIG. 5 in other points. Therefore, the differences will be described in detail while omitting the description of the common points.

  As shown in FIG. 12, the one-way hydraulic pump 24 u is rotationally driven by the table driving motor 8, and discharges hydraulic oil at a flow rate corresponding to the rotation speed of the table driving motor 8 from the discharge port.

  The table driving motor 8 is driven according to the current supplied by the motor driver 8A. The motor driver 8A supplies current to the table driving motor 8 in accordance with a flow rate command from the main controller 9A of the control device 9.

  The direction control valve 25 is a valve that switches the flow direction of the hydraulic oil in the open circuit hydraulic system, and is, for example, a 4-port 2-position electromagnetic valve that uses switching by a solenoid. The direction control valve 25 may be a proportional valve or a servo valve. Specifically, the direction control valve 25 has two valve positions, a first position and a second position. The first position allows the discharge port of the one-way hydraulic pump 24u and the first pressure chamber 21SF of the cylinder 21 to communicate with each other, and allows the second pressure chamber 21SB of the cylinder 21 and the tank T to communicate with each other. The second position allows the discharge port of the one-way hydraulic pump 24u and the second pressure chamber 21SB of the cylinder 21 to communicate with each other, and allows the first pressure chamber 21SF of the cylinder 21 and the tank T to communicate with each other. In FIG. 12, the directional control valve 25 is in the second position, the hydraulic oil discharged from the one-way hydraulic pump 24u flows into the second pressure chamber 21SB, and the hydraulic oil in the first pressure chamber 21SF flows into the tank T. Indicates the state to be performed. FIG. 12 shows a state in which the X-axis table 2 moves in the direction indicated by the arrow AR (−X direction).

  The relief valve 26 is a valve that maintains the pressure at a predetermined pressure while preventing the pressure of the hydraulic oil flowing through the pipe line C1 from exceeding a predetermined pressure (for example, 2 MPa). The pipe line C1 is a pipe line that connects the tank port of the direction control valve 25 and the tank T. The relief valve 26 stabilizes the flow rate of the hydraulic oil flowing out from the cylinder 21 by maintaining the pressure of the hydraulic oil in the pipe line C1 at a predetermined pressure, and thus stabilizes the movement of the X-axis table 2. Can do.

  Further, the relief valve 26 maintains the pressure of the hydraulic oil flowing through the pipe line C1 at a predetermined pressure, so that the hydraulic oil flowing out from the pressure chamber 21S joins the pipe line C3 via the pipe line C2. This is because the working oil flowing out from the cylinder 21 via the pipe C2 is returned to the suction port of the one-way hydraulic pump 24u to effectively use the back pressure. The pipe C2 is a pipe connecting the pipe C1 and the pipe C3, and the pipe C3 is a pipe connecting the suction port of the one-way hydraulic pump 24u and the tank T.

  The check valve 27 is a valve that is installed on the pipe C2 and prohibits the flow of hydraulic oil from the pipe C3 to the pipe C1. The check valve 28 is a valve that is installed on the pipe C3 and prohibits the flow of hydraulic oil from the one-way hydraulic pump 24u to the tank T. The check valves 27 and 28 are required when returning the hydraulic oil flowing out from the cylinder 21 to the cylinder 21 via the pipe line C2.

  The function of returning the hydraulic oil flowing out from the cylinder 21 to the one-way hydraulic pump 24u may be omitted. In this case, the pipe line C2 and the check valves 27 and 28 are omitted. Further, when the pipe line C2 is omitted, the relief valve 26 may be omitted.

  As shown in FIG. 13, the main controller 9 </ b> A acquires various command values including at least one of a table position command, a table speed command, a table acceleration command, and a motor speed command from the control device 9. And main controller 9A acquires various sensor outputs as needed. The various sensor outputs include at least one of a table position signal output from the displacement sensor 30, a cylinder pressure signal output from the cylinder pressure sensors 31F and 31B, and a motor rotation angle signal output from the rotation angle sensor 32.

  Thereafter, the main controller 9A generates a flow rate command based on the acquired various command values and various sensor outputs. The main controller 9A generates a flow rate command using, for example, the configuration described in any of FIGS. Then, the main controller 9A supplies the directional control valve 25 with a current having a predetermined magnitude selected according to whether the sign of the flow rate command is positive or negative. This is because the direction control valve 25 switches the valve position. Specifically, the main controller 9A relates to the sign of the flow rate command from the I / O port for operating the direction control valve to the relay 9B for connecting / disconnecting the current source (not shown) and the direction control valve 25. Output information. The relay 9B connects the current source and the direction control valve 25 when the sign of the flow rate command is positive, so that the valve position of the direction control valve 25 becomes the first position. On the other hand, when the sign of the flow rate command is negative, the relay 9B shuts off the current source and the direction control valve 25 so that the valve position of the direction control valve 25 becomes the second position. The main controller 9A may supply current directly to the direction control valve 25 without using the relay 9B. One of the two predetermined currents may be zero.

  The main controller 9A outputs information on the absolute value of the flow rate command to the motor driver 8A from the I / O port for operating the table driving motor. The motor driver 8A supplies a current of a magnitude corresponding to the absolute value of the flow rate command from the main controller 9A to the table driving motor 8. The table driving motor 8 rotates at a rotation speed corresponding to the current supplied by the motor driver 8A, and rotates the one-way hydraulic pump 24u. The one-way hydraulic pump 24 u discharges hydraulic oil from the discharge port, and supplies the hydraulic oil to any one of the pressure chambers 21 </ b> S of the cylinder 21 through the direction control valve 25.

  With the above configuration, the table moving mechanism 20V can achieve the same effect as that using the bidirectional hydraulic pump 24 by using the unidirectional hydraulic pump 24u and the directional control valve 25. Specifically, the table moving mechanism 20V can reduce or prevent the table speed of the X-axis table 2 from overshooting the value of the speed command. Further, the table moving mechanism 20V can shorten the settling time of the table speed of the X-axis table 2.

  In addition, the one-way hydraulic pump 24u is less expensive than the bidirectional hydraulic pump 24, and a large-capacity pump is easy to manufacture. Therefore, the design flexibility of the table moving mechanism 20V including the one-way hydraulic pump 24u is increased. Can do.

  Next, still another embodiment of the table moving mechanism will be described with reference to FIG. FIG. 14 is a schematic diagram illustrating a configuration example of the table moving mechanism 20W, and corresponds to FIG.

  The table moving mechanism 20W employs a directional control valve 25A instead of the directional control valve 25, and omits the conduit C2, the relief valve 26, the check valve 27, and the check valve 28 in FIG. This is different from the table moving mechanism 20V. However, the table moving mechanism 20W is common to the table moving mechanism 20V of FIG. 12 in other points. Therefore, the differences will be described in detail while omitting the description of the common points.

  The direction control valve 25A is a valve that switches the direction of the flow of hydraulic fluid in the open circuit hydraulic system, and is, for example, a four-port, three-position electromagnetic valve that uses switching by a solenoid. The direction control valve 25A may be a proportional valve or a servo valve. Specifically, the direction control valve 25A has three valve positions, a first position, a second position, and a third position. The first position and the second position are the same as the first position and the second position of the directional control valve 25 in FIG. The third position shuts off the discharge port of the one-way hydraulic pump 24u and the pressure chamber 21S of the cylinder 21, and shuts off the pressure chamber 21S of the cylinder 21 and the tank T. FIG. 14 shows a state in which the directional control valve 25 is in the third position and the X-axis table 2 is stationary.

  With the above configuration, the table moving mechanism 20W can realize the same effects as the table moving mechanism 20 and the table moving mechanism 20V.

  In addition, the table moving mechanism 20W can reliably stop the X-axis table 2 by setting the direction control valve 25A to the third position.

  The table moving mechanism 20W may include the conduit C2, the check valve 27, and the check valve 28, may include the relief valve 26, or may include all of them. Also good.

  Next, another embodiment of the table moving mechanism will be described with reference to FIGS. 15 and 16. FIG. 15 is a schematic diagram illustrating a configuration example of the table moving mechanism 20X, and corresponds to FIG. FIG. 16 is a view showing a control flow when the surface grinding machine 100 on which the table moving mechanism 20X is mounted moves the X-axis table 2, and corresponds to FIG.

  The table moving mechanism 20X is different from the table moving mechanism 20V of FIG. 12 in that a table driving constant speed motor 8uf is provided instead of the table driving motor 8 which is a variable speed motor. Further, the table moving mechanism 20X is different from the table moving mechanism 20V of FIG. 12 in that a swash plate type variable displacement unidirectional hydraulic pump 24uv and a swash plate driving unit 29 are provided instead of the unidirectional hydraulic pump 24u. However, the table moving mechanism 20X is common to the table moving mechanism 20V of FIG. 12 in other points. Therefore, the differences will be described in detail while omitting the description of the common points.

  The table driving constant speed motor 8uf is a motor that rotates at a predetermined speed in one direction, and is driven according to the current supplied by the motor driver 8A. The motor driver 8A rotates the table driving constant speed motor 8uf in response to the ON command from the main controller 9A, and stops the table driving constant speed motor 8uf in response to the OFF command. The table driving constant speed motor 8uf may be driven by a current directly supplied from a power source. In this case, the motor driver 8A is not necessary. Further, a variable speed motor may be used instead of the table driving constant speed motor 8uf.

  The one-way hydraulic pump 24uv is a swash plate type variable displacement hydraulic pump, and changes the discharge amount per one rotation according to the change of the swash plate tilt angle. In the present embodiment, the one-way hydraulic pump 24uv increases the discharge amount per rotation as the swash plate tilt angle increases. Therefore, the one-way hydraulic pump 24uv can change the discharge amount per unit time according to the change of the swash plate tilt angle even if the rotation speed is constant.

  The swash plate drive unit 29 is a functional element for driving and controlling the swash plate of the one-way hydraulic pump 24uv. In the present embodiment, the swash plate driving unit 29 includes a motor driver 29A and a swash plate driving motor 29B.

  The motor driver 29A changes the tilt angle of the swash plate of the one-way hydraulic pump 24uv by positioning the swash plate driving motor 29B in accordance with the absolute value of the flow rate command from the main controller 9A. The swash plate driving motor 29B is, for example, a stepping motor, and changes the tilt angle of the swash plate of the one-way hydraulic pump 24uv in accordance with a driving pulse from the motor driver 29A.

  Here, referring to FIG. 16, the main controller 9 </ b> A acquires various command values from the control device 9. And main controller 9A acquires various sensor outputs as needed. Thereafter, the main controller 9A generates a flow rate command based on the acquired various command values and various sensor outputs. The main controller 9A generates a flow rate command using, for example, the configuration described in any of FIGS. Then, the main controller 9A supplies the directional control valve 25 with a current having a predetermined magnitude selected according to whether the sign of the flow rate command is positive or negative. This is because the direction control valve 25 switches the valve position. The main controller 9A may supply current directly to the direction control valve 25 without using the relay 9B. One of the two predetermined currents may be zero.

  The main controller 9A outputs an on / off command to the motor driver 8A from the I / O port for operating the table driving motor. The motor driver 8A supplies a current to the table driving constant speed motor 8uf in response to an ON command from the main controller 9A. The table driving constant speed motor 8uf rotates according to the current supplied by the motor driver 8A, and rotates the one-way hydraulic pump 24uv in a predetermined direction at a predetermined speed.

  The main controller 9A outputs information on the absolute value of the flow rate command to the motor driver 29A from the I / O port for operating the swash plate driving motor. The motor driver 29A positions the swash plate driving motor 29B in accordance with the absolute value of the flow rate command from the main controller 9A. The swash plate driving motor 29B rotates in accordance with the drive pulse from the motor driver 29A, and changes the swash plate tilt angle of the one-way hydraulic pump 24uv. The one-way hydraulic pump 24uv discharges hydraulic oil corresponding to the swash plate tilt angle from the discharge port, and supplies the hydraulic oil to one of the pressure chambers 21S of the cylinder 21 via the direction control valve 25. .

  With the above configuration, the table moving mechanism 20X includes the one-way hydraulic pump 24uv and the directional control valve 25, which are rotationally driven by the table driving constant speed motor 8uf and whose swash plate tilt angle is adjusted by the swash plate driving unit 29. By using it, the same effect as when using the bidirectional hydraulic pump 24 as shown in FIG. 5 can be realized. Moreover, the same effect as the case of using the fixed displacement type one-way hydraulic pump 24u and the directional control valves 25 and 25A that are rotationally driven by a variable speed motor as shown in FIGS. 12 and 14 can be realized.

  In addition, the one-way hydraulic pump 24uv is less expensive than the bidirectional hydraulic pump 24, and a large-capacity pump is easy to manufacture. Therefore, the design flexibility of the table moving mechanism 20X including the one-way hydraulic pump 24uv is increased. Can do.

  Next, still another embodiment of the table moving mechanism will be described with reference to FIGS. 17 and 18. FIG. 17 is a schematic diagram illustrating a configuration example of the table moving mechanism 20Y, and corresponds to FIG. FIG. 18 is a diagram showing a control flow when the surface grinding machine 100 on which the table moving mechanism 20Y is mounted moves the X-axis table 2, and corresponds to FIG.

  The table moving mechanism 20Y is different from the table moving mechanism 20 of FIG. 5 in that a table driving constant speed motor 8bf is provided instead of the table driving motor 8 which is a variable speed motor. The table moving mechanism 20Y is different from the table moving mechanism 20 of FIG. 5 in that a swash plate type variable displacement bidirectional hydraulic pump 24bv and a swash plate driving unit 29 are provided instead of the bidirectional hydraulic pump 24. However, the table moving mechanism 20X is common to the table moving mechanism 20 of FIG. 5 in other points. Therefore, the differences will be described in detail while omitting the description of the common points.

  The table driving constant speed motor 8bf is a motor that can rotate in both directions at a predetermined speed. In this embodiment, the table driving constant speed motor 8bf is a three-phase AC motor and is driven according to the current supplied by the motor driver 8A. The motor driver 8A supplies a current to the table driving constant speed motor 8bf according to the flow rate command from the main controller 9A. The table driving constant speed motor 8bf is switched between forward rotation and reverse rotation by switching two phases. The forward / reverse switching of the table driving constant speed motor 8bf may be performed using the motor driver 8A. A variable speed motor may be used instead of the table driving constant speed motor 8bf.

  The bidirectional hydraulic pump 24bv is a swash plate type variable displacement hydraulic pump, and changes the discharge amount per one rotation according to the change of the swash plate tilt angle. In the present embodiment, the bidirectional hydraulic pump 24bv increases the discharge amount per rotation as the swash plate tilt angle increases. Therefore, the bidirectional hydraulic pump 24bv can change the discharge amount per unit time according to the change of the swash plate tilt angle even if the rotation speed is constant.

  The swash plate driving unit 29 is a functional element for driving and controlling the swash plate of the bidirectional hydraulic pump 24bv. In the present embodiment, the swash plate driving unit 29 includes a motor driver 29A and a swash plate driving motor 29B.

  The motor driver 29A positions the swash plate driving motor 29B in accordance with the absolute value of the flow rate command from the main controller 9A. The swash plate driving motor 29B is, for example, a stepping motor, and changes the tilt angle of the swash plate of the bidirectional hydraulic pump 24bv in accordance with a driving pulse from the motor driver 29A.

  Referring now to FIG. 18, the main controller 9 </ b> A acquires various command values from the control device 9. And main controller 9A acquires various sensor outputs as needed. Thereafter, the main controller 9A generates a flow rate command based on the acquired various command values and various sensor outputs. The main controller 9A generates a flow rate command using, for example, the configuration described in any of FIGS. The main controller 9A outputs information related to the sign of the flow rate command to the motor driver 8A from the I / O port for operating the table driving motor. The motor driver 8A supplies the table drive constant speed motor 8bf with an electric current having a predetermined magnitude selected according to whether the sign of the flow rate command from the main controller 9A is positive or negative. The table driving constant speed motor 8bf rotates in a predetermined direction at a predetermined speed according to a current supplied by the motor driver 8A, and rotates the bidirectional hydraulic pump 24bv in a predetermined direction at a predetermined speed.

  The main controller 9A outputs information on the absolute value of the flow rate command to the motor driver 29A from the I / O port for operating the swash plate driving motor. The motor driver 29A positions the swash plate driving motor 29B in accordance with the absolute value of the flow rate command from the main controller 9A. The swash plate driving motor 29B rotates in accordance with the drive pulse from the motor driver 29A, and changes the swash plate tilt angle of the bidirectional hydraulic pump 24bv. The bidirectional hydraulic pump 24bv discharges hydraulic oil corresponding to the swash plate tilt angle from one of the first port 24F and the second port 24B, and operates to either one of the pressure chambers 21S of the cylinder 21. Supply oil.

  With the above-described configuration, the table moving mechanism 20Y includes the swash plate type variable displacement bidirectional hydraulic pump 24bv that is rotationally driven by the table driving constant speed motor 8bf and whose swash plate tilt angle is adjusted by the swash plate drive unit 29. By using this, it is possible to realize the same effect as in the case of using a fixed displacement bidirectional hydraulic pump rotated by a variable speed motor as shown in FIG.

  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 surface grinding machine 100 employs the horizontal axis grinding wheel head 4, but may adopt a vertical axis grinding wheel head. Moreover, the grindstone head may include a tiltable shaft.

  In the above-described embodiment, the main controller 9A controls the flow rate and flow direction of the hydraulic oil in the hydraulic system as the table moving mechanism of the surface grinding machine 100. However, the present invention is not limited to this. For example, the main controller 9A may control the flow rate and flow direction of hydraulic oil in a hydraulic system that moves heavy objects, which is mounted on a construction machine, an injection molding machine, a machine tool, or the like.

  In the above-described embodiment, the hydraulic system uses the pressure (hydraulic pressure) of the hydraulic oil. However, the present invention is not limited to this. For example, the hydraulic system may use the pressure (hydraulic pressure) of a liquid having low compressibility such as water instead of the hydraulic pressure.

  In the above-described embodiment, the main controller 9A controls the flow rate and flow direction of the hydraulic oil in the hydraulic system by the electric motor. However, the present invention is not limited to this. The main controller 9A may control the flow rate and flow direction of hydraulic oil in the hydraulic system, for example, by an internal combustion engine.

  DESCRIPTION OF SYMBOLS 1 ... Main body bed 1AL, 1AR ... Rail groove | channel 2 ... X-axis table 2BL, 2BR ... Guide rail 3 ... Horizontal axis grindstone column 4 ... Horizontal axis grindstone head 5 ... Wheel head rotation motor 6 ... Wheel head vertical feed motor 7 ... Wheel head left / right feed motor 8 ... Table drive motor 8A ... Motor driver 8uf, 8bf ... Table drive constant speed Motor 9 ... Control device 9A ... Main controller 20 ... Table moving mechanism 21 ... Cylinder 21S ... Pressure chamber 21SF ... First pressure chamber 21SB ... Second pressure chamber 22 ..Piston 23F ... first shaft 23B ... second shaft 23Fa, 23Ba ... stationary object 24 ... bidirectional hydraulic pump 24F ... first port 24B ... second port DOO 30 ... displacement sensor 31F, 31B ... cylinder pressure sensor 32 ... rotation angle sensor 40 ... wheel spindle 41 ... grinding wheel 100 ... Surface Grinder W ... work

Claims (9)

A surface grinder for moving a movable table using a hydraulic system capable of adjusting a flow rate and a flow direction of a working fluid,
A control device for controlling the movement of the movable table with the position or speed of the movable table as a control target;
A main controller that controls a flow rate and a flow direction of the working fluid in accordance with a table position command or a table speed command from the control device and an acceleration of the movable table;
Surface grinding machine. The hydraulic system is a closed circuit hydraulic system including a bidirectional hydraulic pump;
The main controller controls the rotational speed of the bidirectional hydraulic pump according to a table position command or a table speed command from the control device and an acceleration of the movable table.
The surface grinding machine according to claim 1. The hydraulic system includes a hydraulic cylinder having a first pressure chamber and a second pressure chamber,
The main controller acquires an acceleration of the movable table based on a differential pressure between the first pressure chamber and the second pressure chamber;
The surface grinding machine according to claim 1 or 2. A displacement sensor for detecting the displacement of the movable table;
The main controller acquires the acceleration of the movable table based on a second-order derivative of the displacement detected by the displacement sensor.
The surface grinding machine according to claim 1 or 2. A speed sensor for detecting the speed of the movable table;
The main controller acquires the acceleration of the movable table based on the first derivative of the displacement detected by the speed sensor.
The surface grinding machine according to claim 1 or 2. An acceleration sensor for detecting the acceleration of the movable table;
The main controller acquires the acceleration of the movable table based on a value detected by the acceleration sensor;
The surface grinding machine according to claim 1 or 2. The hydraulic system is a closed circuit hydraulic system including a bidirectional hydraulic pump;
The main controller controls a swash plate tilt angle of the bidirectional hydraulic pump according to a table position command or a table speed command from the control device and an acceleration of the movable table.
The surface grinding machine according to claim 1. The hydraulic system is an open circuit hydraulic system including a unidirectional hydraulic pump,
The main controller controls the number of rotations of the one-way hydraulic pump according to a table position command or a table speed command from the control device and an acceleration of the movable table.
The surface grinding machine according to claim 1. The hydraulic system is an open circuit hydraulic system including a unidirectional hydraulic pump,
The main controller controls a swash plate tilt angle of the one-way hydraulic pump according to a table position command or a table speed command from the control device and an acceleration of the movable table.
The surface grinding machine according to claim 1.

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