JP5415871B2 - Precision processing machine - Google Patents

Description

  The present invention relates to a precision processing machine, and more specifically, a precision in which static pressure oil supplied to a hydrostatic pressure sliding surface is temperature-controlled based on the temperature of a portion placed in a room temperature environment in a block body. It relates to processing machines.

  In surface grinding machines, etc., with the workpiece placed on a machining table that reciprocates in the X-axis direction, the spindle is rotated on a Z-axis saddle that is mounted on a column that reciprocates in the Y-axis direction and reciprocates in the vertical direction. While supporting freely, a grindstone is attached to the tip of the spindle. Then, the workpiece on the processing table is ground by rotating the spindle and the grindstone.

  In general, in a processing machine that requires precision machining, not limited to a surface grinder, a machining table, a column, a Z-axis saddle, and the like are supported on a hydrostatic pressure sliding surface in a reciprocating manner at each part of the machine. And since there is not a little heat generation in this hydrostatic pressure sliding surface, the temperature rise of the hydrostatic pressure sliding surface and its vicinity is suppressed. Further, the temperature of the scale provided in the vicinity of the hydrostatic sliding surface may be out of the allowable temperature range in precision machining, and temperature correction is performed.

  In the “NC machine tool device” disclosed in Patent Document 1, temperature detection means is provided in the digital scale, and the temperature of the coolant is controlled based on the temperature of the digital scale detected by the temperature detection means. Yes. Then, the temperature of the workpiece is controlled by the coolant liquid whose temperature is controlled so that the temperature of the workpiece becomes equal to the temperature of the digital scale. Furthermore, the measurement value correction of the digital scale is calculated based on the temperature of the digital scale and the linear expansion coefficient of the digital scale and the workpiece, and the NC machine tool is controlled based on the corrected measurement value.

  In the "Method for reducing thermal deformation of a hydrostatic main spindle for precision processing machines" disclosed in Patent Document 2, the entire precision processing machine is installed in a constant temperature environment where temperature control is performed, and the working fluid that performs fluid lubrication of the hydrostatic main spindle is used. The temperature is lower than the temperature of the surrounding constant temperature environment and the thermal deformation of the hydrostatic main shaft is controlled. In this way, the influence of heat generated in the working fluid is effectively removed, and the thermal deformation of the hydrostatic main spindle is effectively reduced.

Japanese Patent Laid-Open No. 4-75851 (see [Claims]) JP-A-6-198539 (see [Summary], Detailed Description of the Invention [0010])

  In recent years, precision machining has enabled ultra-precision machining at a level of 10 nm, but there is a demand for the realization of precision machining capable of constantly obtaining machining accuracy of 1 μm or less. It is not enough to simply install the machine in a temperature-controlled room. In addition to fine temperature control for each part of the machine, overall high-harmonic temperature control is achieved, resulting in steady high-precision machining. It has become clear that

  However, in the apparatus of Patent Document 1, the temperature of the workpiece and the temperature of the digital scale are made equal, but a machine main body provided with a digital scale between the digital scale and the workpiece, and on the machine main body. There is a processing table supported so as to be capable of reciprocating. These are usually placed in different temperature conditions even in a constant temperature environment. For example, the sliding surface between the machine body and the processing table always generates heat, and deformation due to the heat cannot be ignored in precision processing. Therefore, even if the temperature of the workpiece and the temperature of the digital scale are made equal and the measurement value is corrected based on the linear expansion coefficient or the like, there is a limit to the machining accuracy that can be obtained.

  The thermal deformation reduction method of Patent Document 2 is intended to remove the influence of heat generated in the working fluid, and seems to be excellent in that individual temperature control is performed. However, this reduction method only uses a working fluid having a temperature lower (5 to 10 degrees C lower) than the temperature of the surrounding constant temperature environment to suppress thermal deformation of the hydrostatic main shaft. That is, neither thermal deformation is made zero nor thermal deformation is controlled to a constant value. Therefore, it seems that there is a limit to the processing accuracy that can be obtained even in this thermal deformation reduction method.

  The present invention has been made paying attention to such problems, and the object of the present invention is to provide precision capable of stably obtaining high machining accuracy by controlling the temperatures of the machine body, scale, workpiece, etc. It is to provide a processing machine.

In order to solve the above-mentioned problem, the precision machining machine according to claim 1 is characterized in that in the precision machining machine provided with a block body that supports a saddle so as to be reciprocally movable on a hydrostatic pressure sliding surface, the hydrostatic pressure is provided. When the hydrostatic oil supplied to the sliding surface is supplied to the hydrostatic sliding surface, the portion of the block body provided with the hydrostatic sliding surface is placed in a room temperature environment. The temperature is adjusted based on the temperature, and the hydrostatic oil is adjusted in temperature and then circulates in a circuit formed on a support plate that supports the scale for measuring the position of the saddle, thereby adjusting the temperature of the scale. It is characterized by this.

According to the above configuration, the temperature of the hydrostatic oil is adjusted based on the temperature of the portion of the block body provided with the hydrostatic sliding surface placed in a room temperature environment. For this reason, even if the oil hydrostatic sliding surface generates heat, the temperature of the hydrostatic oil for removing the influence of the heat generation can be adjusted according to the temperature condition of the block body. Therefore, it is possible to prevent the block body from being bent and deformed as a whole due to the difference in temperature distribution. In addition, a circuit is formed on a support plate that supports the scale, and the hydrostatic oil whose temperature is adjusted flows through the circuit. For this reason, the temperature condition of the scale is determined by the temperature-controlled support plate and the atmosphere in the room where the machine is installed. Therefore, the temperature of the scale can be adjusted stably.

  According to a second aspect of the present invention, in the precision processing machine according to the first aspect, the hydrostatic oil is a surface of the block body that is farthest from the surface on which the hydrostatic sliding surface is provided or in the vicinity thereof. The temperature is adjusted based on the temperature measured in (1).

  According to the said structure, the temperature measurement of the block body was performed in the surface farthest from the surface in which the hydrostatic pressure sliding surface was provided, or its vicinity. For this reason, the hydrostatic pressure sliding surface is provided and is different from the surface that is affected by the temperature of the hydrostatic oil, and the temperature of the hydrostatic oil is under the temperature environment in the room where the machine is installed. The temperature of the hydrostatic oil can be adjusted based on the temperature of the surface that is not affected.

According to a third aspect of the present invention, in the precision processing machine according to the first or second aspect , the scale is covered with a heat insulating material in which a slit that allows movement of a head that reads the scale is formed. It is a feature.

  According to the above configuration, since the scale is covered with the heat insulating material, even if the temperature environment in the room where the machine is installed is disturbed, the temperature of the scale can be efficiently adjusted with hydrostatic oil. .

  According to the present invention, the temperature of the hydrostatic oil supplied to the hydrostatic sliding surface is determined based on the temperature of the portion placed in a room temperature environment in the block body provided with the hydrostatic sliding surface. I adjusted it. For this reason, since the deformation | transformation etc. by the temperature in each location of a block body differing can be suppressed, the precision processing machine which can obtain high processing accuracy stably can be provided.

The perspective view which shows the precision processing machine of embodiment. The perspective view of the partial cross section which shows the position measuring apparatus using a scale. The related figure explaining the control based on the temperature of each site | part.

(Embodiment)
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to FIGS.
As shown in FIG. 1, a surface grinding machine 1 as a precision processing machine according to the present embodiment includes a main bed portion 2 extended along the X-axis direction and a Y-axis direction orthogonal to the X-axis direction. A bed is formed with the extended sub bed portion 3. On the two rows of hydrostatic pressure sliding surfaces 9 provided on the main surface 21 on the upper surface of the main bed portion 2, a processing table 5 constituting a saddle is supported so as to be capable of reciprocating. A workpiece 6 is placed on the processing table 5. In addition, the main bed part 2 and the subbed part 3 each comprise a block body.

  A position measuring device 12 is provided at the upper end side of the side surface 22 that contacts the front surface of the main bed portion 2 so as to extend in the X-axis direction, and the scale on the scale 50 (see FIG. 2) of the position measuring device 12 is optically read. Read head 13 is provided on the processing table 5. In the main bed 2, a measurement point 20 for measuring a temperature that is a basis for temperature adjustment of the hydrostatic oil is provided on a bottom surface 23 that is the surface farthest from the main surface 21 together with a sensor (not shown). Instead of the measurement point 20, the measurement point 44 can be provided together with the sensor on the lower end side of the side surface 22, that is, on the side surface 22 near the bottom surface 23. The measurement point 20 or the measurement point 44 is a point for measuring the temperature of the main bed portion 2 as a portion that is placed in a room temperature environment and is not subjected to temperature control.

  As shown in FIG. 2, the position measurement device 12 is disposed so as to surround the support plate 51 attached to the side surface 22 of the main bed 2, the scale 50 supported by the support plate 51, and the scale 50. It is comprised with the heat insulating material 53. FIG. In this embodiment, as a part of the static pressure oil circuit on the mounting surface of the support plate 51, two grooves 52 along the longitudinal direction are formed, and the static pressure oil circulates in the grooves 52. The temperature of the scale 50 is adjusted via the support plate 51.

  A slit 54 is formed in the heat insulating material 53 in the longitudinal direction along the side surface 22, and the reading head 13 can move along the slit 54 in a state where the reading unit 55 of the reading head 13 is accommodated therein. The reading unit 55 is a part that is arranged close to the scale 50 and optically reads the scale of the scale 50.

  On the main surface 31 on the upper surface of the sub-bed portion 3, there are provided two rows of hydrostatic sliding surfaces 10 that support the column 4 constituting the saddle so as to reciprocate in the Y-axis direction. Further, a position measuring device 14 is provided on the upper end side of the side surface 32 of the sub bed portion 3 so as to extend in the Y-axis direction, and the read head 15 corresponding to the position measuring device 14 is provided on the lower end side of the side surface 42 of the column 4. Is provided. A measurement point 30 for measuring a temperature that is a basis for temperature adjustment of the hydrostatic oil is provided on a bottom surface 33 that is a surface farthest from the main surface 31 of the sub bed portion 3 together with a sensor (not shown). Instead of the measurement point 30, the measurement point 45 can be provided together with the sensor on the lower end side of the side surface 32, that is, on the side surface 32 in the vicinity of the bottom surface 33. The measurement point 30 or the measurement point 45 is a point for measuring the temperature of the sub bed portion 3 as a portion that is placed in a room temperature environment and not subjected to temperature control. Since the position measuring device 14 has the same configuration as the position measuring device 12, the description thereof is omitted.

  The main surface 41 on the main bed portion 2 side of the column 4 constituting the block body is provided with two rows of hydrostatic pressure sliding surfaces 11 that support the saddle 8 so as to reciprocate in the Z-axis direction. A spindle (not shown) is rotatably supported on the frame 81 connected to the saddle 8, and a grindstone 7 is attached to the tip of the spindle. The cover 71 that covers the grindstone 7 is provided with a discharge head 72 for discharging the coolant liquid to the workpiece 6.

  Further, a position measuring device 16 is provided at the end of the side surface 42 of the column 4 on the main surface 41 side so as to extend in the Z-axis direction, and a read head 17 corresponding to the position measuring device 16 is provided in the saddle 8. Yes. Since the position measuring device 16 has the same configuration as the position measuring device 12, the description thereof is omitted.

  A measuring point 40 for measuring a temperature that is a basis for temperature adjustment of the hydrostatic oil is provided on a back surface 43 that is the surface farthest from the main surface 41 of the column 4 together with a sensor (not shown). In place of the measurement point 40, the measurement point 46 can be provided together with the sensor on the back side of the side surface 42, that is, on the side surface 42 in the vicinity of the back surface 43. The measurement point 40 or the measurement point 46 is a point for measuring the temperature of the column 4 that is placed in a room temperature environment and is not subjected to temperature control.

Next, the operation of this embodiment will be described.
In the surface grinding machine 1 as the precision processing machine of the present embodiment, the temperature of the machine body is stably controlled in the place where it is installed, for example, in the temperature environment of a constant temperature room. However, various disturbance elements that disturb stable temperature management are added to each part of the airframe. In the present embodiment, in order to remove the influence of the heat generation of the hydrostatic oil, which has the greatest influence among the disturbance elements, the temperature of the hydrostatic oil whose temperature has been increased is adjusted, and the hydrostatic pressure whose temperature has been adjusted is adjusted. The temperature of the scale 50 was adjusted with oil.

  Further, the operation of the temperature control of the scale 50 and related parts will be described with reference to FIG. Note that the description relates to the main bed portion 2, but in the portion surrounded by the two-dot chain line in FIG. 3, the description related to each of the sub bed portion 3, the column 4, etc. is applied. Can be replaced. The flow of static pressure oil is indicated by a thick solid line, and the electrical flow of data and signals is indicated by a thin solid line.

  The hydrostatic oil in the hydrostatic oil tank 60 is sent out by a hydrostatic oil pump 61. The hydrostatic oil is controlled by a pressure control valve (not shown) and the like, and then the temperature is adjusted by the temperature adjusting device 62 and supplied to the hydrostatic pressure sliding surface 9. At the same time, the temperature-adjusted hydrostatic oil is subjected to temperature adjustment of the scale 50 of the position measuring device 12. The surplus hydrostatic oil is collected in the hydrostatic oil tank 60.

  The temperature adjusting device 62 is in the circuit of the hydrostatic oil, and based on the body temperature 64, that is, the temperature of the main bed portion 2 measured at the measurement point 20, the temperature and the hydrostatic pressure sliding surface 9 temperature. It is controlled by the control device 63 so as to eliminate the difference from 65, and adjusts the temperature of the hydrostatic oil. Normally, the temperature of the hydrostatic oil rises due to frictional heat due to viscosity, and therefore the temperature is adjusted in the direction of lowering the hydrostatic oil temperature to the temperature of the main bed 2. The temperature is adjusted so that the difference between the temperature of the hydrostatic sliding surface 9 and the temperature of the main bed 2 is always within a predetermined range. At this time, the scale 50 arranged near the hydrostatic sliding surface 9 and affected by the temperature rise of the hydrostatic sliding surface 9 is also set to the same temperature as the temperature of the main bed 2. Adjusted. For this reason, since the temperature of the main bed part 2, the temperature of the hydrostatic pressure sliding surface 9, and the temperature of the scale 50 are substantially the same, when correcting the measurement value by the scale, the temperature between each part The effect of the difference can be minimized.

  Further, the control unit 68 calculates a correction value from the temperatures 70 and 66 and the linear expansion coefficient 67 of the workpiece 6 and the scale 50, and outputs them as an axial position correction value 69. For this reason, the temperature of the coolant is adjusted based on the temperature of the portion of the main surface 41 of the column 4 that is substantially the same height as the workpiece 6. Then, the coolant liquid whose temperature has been adjusted is discharged from the discharge head 72 to the work 6 so that the temperature of the work 6 is adjusted.

  As described above, what is shown in FIG. 3 is based on the hydrostatic pressure sliding surface 10 and the scale 50 of the position measuring device 14 when the airframe temperature 64 is based on the temperature of the measurement point 30 of the subbed portion 3. And the relationship. 3 is based on the temperature of the measurement point 40 of the column 4 as the airframe temperature 64, the relationship between the hydrostatic sliding surface 11 and the scale 50 of the position measuring device 16 may be used. it can.

  In addition to the above configuration, if the temperature of a spindle (not shown) with a grindstone 7 attached to the tip is adjusted so that the temperature of the spindle does not vary in the axial direction, higher machining accuracy is more stable. Thus, the surface grinding machine 1 can be obtained. For this reason, it is preferable to measure the temperature and flow rate of the cooling oil supplied to the quill based on the temperature measured at least at two positions on the front end side and the rear end side of the spindle or the quill supporting the spindle. .

Therefore, according to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the temperature of the hydrostatic oil is based on the temperature of the block body such as the column 4 provided with the hydrostatic pressure sliding surfaces 9, 10, 11, the main bed portion 2, and the auxiliary bed portion 3. Adjustment was performed for each of the hydrostatic pressure sliding surfaces 9, 10, 11 to which the hydrostatic oil was supplied. For this reason, even if the hydrostatic pressure sliding surfaces 9, 10 and 11 generate heat, the temperature adjustment of the hydrostatic oil for removing the influence of the heat generation is performed according to the temperature condition of each block body. Can do. Therefore, since each block body can be prevented from being deformed because the temperature varies depending on the part, it is possible to provide a precision processing machine capable of stably obtaining high processing accuracy.

  (2) In the above embodiment, the main surfaces 21, 31 provided with the hydrostatic pressure sliding surfaces 9, 10, 11 are used to measure the temperature of the block bodies such as the column 4, the main bed portion 2, and the auxiliary bed portion 3. The measurement is performed at the measurement points 20, 30, and 40 on the bottom surfaces 23 and 33 and the back surface 43, which are the surfaces farthest from 41. For this reason, unlike the main surfaces 21, 31, and 41 that are affected by the temperature of the hydrostatic oil, the bottom surface is not affected by the temperature of the hydrostatic oil in the indoor temperature environment in which the surface grinding machine 1 is installed. The temperature of the hydrostatic oil can be adjusted on the basis of the temperatures of 23 and 33 and the back surface 43.

  (3) In the above embodiment, the groove 52 as a circuit is formed in the support plate 51 that supports the scale 50, and the hydrostatic oil whose temperature is adjusted flows through the groove 52. Therefore, the temperature condition of the scale 50 is determined by the temperature-adjusted support plate 51 and the atmosphere in the room where the surface grinding machine 1 is installed. Therefore, the temperature of the scale 50 can be adjusted stably.

  (4) In the above embodiment, since the scale 50 is covered with the heat insulating material 53, even if the temperature environment in the room where the surface grinding machine 1 is installed is disturbed, the temperature adjustment of the scale 50 with the hydrostatic oil is efficient. Can be done automatically.

(Example of change)
In addition, the said embodiment can also be changed and actualized as follows.
Although the support plate 51 that supports the scale 50 is provided, the scale 50 is directly attached to the side surfaces 22, 32, and 42 of the main bed portion 2, the sub bed portion 3, and the column 4 without providing the support plate 51. In that case, circuits, such as a groove | channel which enables the distribution | circulation of a static pressure oil, are formed in the side surfaces 22,32,42.
-Although the two grooves 52 along the longitudinal direction are formed on the support plate 51, the two grooves 52 are meandered and intersected at a plurality of locations.
A bed composed of a main bed portion 2 arranged along the X-axis direction and a sub-bed portion 3 arranged along the Y-axis direction, and the processing table 5 and the column 4 are supported so as to be reciprocally movable in each bed. However, on one bed, the processing table 5 and the column 4 are supported so that they can reciprocate in directions orthogonal to each other.
-Apply the configuration applied to the surface grinder 1 to the cylindrical grinder.

Further, technical ideas that can be grasped from the above-described embodiment are described below together with their effects.
(A) Precision equipped with a position measuring device for measuring the position of the saddle which is supported by a hydrostatic pressure sliding surface provided on the block body and moves on a block body which supports the saddle so as to be able to reciprocate. In the processing machine, the temperature of the scale is adjusted by hydrostatic oil supplied to the hydrostatic sliding surface. In such a configuration, the portion of the block body where the hydrostatic pressure sliding surface of the hydrostatic pressure that is substantially the same as the temperature of the hydrostatic oil is provided, and the scale are substantially the same. In correcting the measured value, the influence of temperature can be minimized.

  4 ... Column, 5 ... Processing table, 8 ... Saddle, 9, 10, 11 ... Hydrostatic sliding surface, 12, 14, 16 ... Position measuring device, 50 ... Scale, 51 ... Support plate, 53 ... Insulating material, 54 ... slit, 65, 70 ... temperature, 71 ... cover.

Claims (3)

In a precision processing machine provided with a block body that supports a saddle so that it can reciprocate on an oil hydrostatic sliding surface, the hydrostatic oil supplied to the hydrostatic sliding surface is placed on the hydrostatic sliding surface. When being supplied, the temperature of the block body provided with the hydrostatic pressure sliding surface is adjusted based on the temperature of the portion placed in a room temperature environment , and the hydrostatic oil is adjusted in temperature, A precision processing machine that circulates in a circuit formed on a support plate that supports a scale for measuring the position of the saddle and adjusts the temperature of the scale .   2. The temperature of the hydrostatic oil is adjusted based on a temperature measured on a surface of the block body that is farthest from a surface on which the hydrostatic pressure sliding surface is provided or in the vicinity thereof. The precision processing machine described in 1. 3. The precision processing machine according to claim 1, wherein the scale is covered with a heat insulating material in which a slit that allows movement of a head for reading the scale is formed.

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