JP5789220B2 - Machine Tools - Google Patents

Description

  The present invention relates to a machine tool including a column such as a horizontal machining center that can slide in a predetermined direction.

  Conventionally, for example, a general machine tool such as a horizontal machining center is provided with a column on which a spindle head is installed on a bed. In such a machine tool, when the temperature of a structure such as a bed or a column changes due to a change in room temperature, for example, the ambient temperature differs depending on the environment on the front and rear surfaces of the structure. There is also a difference in change. Therefore, due to the difference in temperature change, the structure is subject to thermal deformation such as warping and tilting, and as a result, a problem that the dimensional accuracy is lowered is caused.

  Therefore, in view of the above-described problems, the invention described in Patent Document 1 employs a configuration in which a cooling medium is allowed to flow inside the structure to suppress a temperature change itself, thereby suppressing thermal deformation. Moreover, in the invention described in Patent Document 2, an air curtain (that is, a heat insulating layer) is generated on the surface of the structure using a blower or the like, and a temperature change of the structure due to a room temperature change or the like is suppressed. Adopted to suppress thermal deformation.

JP-A-10-249660 JP-A-8-281533

  However, in the configurations described in Patent Documents 1 and 2, peripheral devices such as a cooling medium circulation device (Patent Document 1) and a blower device (Patent Document 2) are required. However, there is a problem that the cost increases. Needless to say, not only the machine tool but also the peripheral devices need to operate normally, that is, many devices that must operate normally are necessary.

  Therefore, the present invention has been made in view of the above problems, and does not require a peripheral device, can be manufactured and operated at low cost, and has a high reliability in terms of the effect of suppressing thermal deformation. Is to provide a machine.

In order to achieve the above object, the invention according to claim 1 of the present invention comprises a bed and a column erected so as to be slidable on the bed in a predetermined direction, and the sliding direction of the column The space on one side of the column is a processing space, the space on the other side is a moving space of the column, and at least the moving space is covered with a cover body, and air is applied to the bed. A first temperature measuring means for providing an air entrance / exit space and communicating the air entrance / exit space and the moving space, while measuring a temperature above the air entrance / exit space in the bed; A second temperature measuring means for measuring a temperature below the air entrance / exit space, a third temperature measuring means for measuring an ambient temperature in the moving space, and the air entrance / exit air Provided with a fourth temperature measuring means for measuring the ambient temperature inside, and a control device for controlling the reciprocating movement of the column based on the measured values by the first to fourth temperature measuring means, The estimated temperature change at the upper part of the bed and the estimated temperature change at the lower part of the bed are calculated at predetermined processing intervals based on the measured values by the first to fourth temperature measuring means, and both are estimated. Based on the temperature change, the difference in the estimated temperature change between the upper part and the lower part of the bed is calculated, and it is determined that the difference in the estimated temperature change exceeds a predetermined limit value during the processing interval. The column is reciprocated to change the air in the moving space and the air in / out space.
In order to achieve the above object, the invention according to claim 2 of the present invention includes a bed and a column slidably installed on the bed in a predetermined direction. A machine tool in which a space on one side of the column in the sliding direction is a processing space, and a space on the other side is a movement space of the column, and at least the movement space is covered with a cover body, A first temperature measuring means for providing an air in / out space through which air can enter and exit, and communicating the air in / out space and the moving space, while measuring a temperature above the air in / out space of the bed; A second temperature measuring means for measuring a temperature below the air entrance / exit space, a third temperature measuring means for measuring an ambient temperature in the moving space, and the air Provided with a fourth temperature measuring means for measuring the ambient temperature in the entrance space, and a control device for controlling the reciprocating movement of the column based on the measured values by the first to fourth temperature measuring means. The apparatus calculates an estimated temperature change at the upper part of the bed and an estimated temperature change at the lower part of the bed based on the measurement values obtained by the first to fourth temperature measuring means at a predetermined processing interval. Based on both estimated temperature changes, the difference in estimated temperature change between the upper part and the lower part of the bed is calculated, and the difference in estimated temperature change is calculated before a predetermined time elapses beyond the processing interval. If it is determined that a predetermined limit value is exceeded, the column is reciprocated to replace the air in the moving space and the air in / out space.
According to a third aspect of the present invention, the control device according to the first or second aspect of the present invention is configured such that the control device detects the measured value by the third temperature measuring unit and the fourth temperature with the start of the reciprocating movement of the column. It is determined whether or not the difference from the measured value by the measuring means has converged below a predetermined ambient temperature limit value, and the reciprocation of the column is stopped when the difference has converged below the predetermined ambient temperature limit value. It is characterized by that.

According to the present invention, the bed is provided with an air entrance / exit space through which air can enter and exit, and the air entrance / exit space and the column moving space are communicated by the duct, while the temperature above the air entrance / exit space in the bed, The temperature below the air access space, the ambient temperature in the moving space, and the ambient temperature in the air access space are measured, and based on those measured temperatures, the estimated temperature change at the top of the bed, Calculate the estimated temperature change in the lower part of the bed and calculate the difference in estimated temperature change between the upper and lower parts of the bed based on both estimated temperature changes. If it is determined that the difference in estimated temperature change exceeds a predetermined limit before the time elapses, the column is reciprocated to exchange the air in the moving space and the air in / out space. Therefore, it is possible to suppress thermal deformation such as warpage and inclination generated in the bed due to the difference in estimated temperature change, and it is possible to realize highly accurate machining. In addition, since a peripheral device is not required separately as in the prior art, not only the manufacturing cost but also the running cost can be kept low, and the number of devices that need to operate normally can be reduced. be able to.
Further, according to the first aspect of the present invention, when it is determined that the difference in estimated temperature change exceeds a predetermined limit value during the processing interval, the column is moved back and forth. The column can be reciprocated at the most recent timing that is likely to exceed the above, and the number of machining interruptions associated with the reciprocating movement of the column, that is, the reduction in machining efficiency can be suppressed. On the other hand, according to the second aspect of the invention, the column is reciprocated when it is determined that the difference in estimated temperature change exceeds the predetermined limit before the predetermined time elapses beyond the processing interval. The column can be reciprocated at the timing, and thermal deformation due to the difference in estimated temperature change can be further suppressed.
According to the third aspect of the present invention, the difference between the ambient temperature in the moving space and the ambient temperature in the air inlet / outlet space converges to a predetermined ambient temperature limit value or less as the column starts to reciprocate. It is determined whether the difference has converged to a predetermined ambient temperature limit value or less, and the column reciprocation is stopped. Therefore, it is possible to ensure that thermal deformation can be reliably suppressed, i.e., no significant difference in estimated temperature change occurs between the upper and lower portions of the bed, and the column can be reciprocated over an unnecessarily long time. In addition, the processing interruption time can be minimized and the processing efficiency can be improved.

It is perspective explanatory drawing which showed the horizontal machining center. It is explanatory drawing which showed the state in which a column exists in an advance position, It is explanatory drawing which showed the state which has a column in a retracted position. It is a flowchart figure which concerns on the suppression control of a thermal deformation. It is a flowchart figure which concerns on the suppression control of a thermal deformation. It is the graph which showed the relationship between the difference of an estimated temperature change, and a limit value. It is the graph which showed the relationship between the difference of an estimated temperature change, and a limit value. It is the graph which showed the relationship between the difference of an estimated temperature change, and a limit value. It is a flowchart figure which concerns on the example of a change of suppression control of a thermal deformation. It is a flowchart figure which concerns on the example of a change of suppression control of a thermal deformation.

  Hereinafter, a machine tool according to an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, the X axis, the Y axis, and the Z axis are orthogonal to each other. The X axis direction is the left-right direction, the Y axis direction is the up-down direction, and the Z-axis direction is the front-rear direction.

FIG. 1 is a perspective explanatory view showing a horizontal machining center 1. FIG. 2 is an explanatory view showing a state where the column 6 is in the forward movement position, and FIG. 3 is an explanatory view showing a state where the column 6 is in the backward movement position. 2 and 3, the left side is described as the front side of the horizontal machining center 1, and the right side is described as the rear side.
The horizontal machining center 1 includes a bed 2 having an X-axis guide rail 3 and a Z-axis guide rail 4 laid on the upper surface, a table 5 attached so as to slide in the left-right direction along the X-axis guide rail 3, and a Z A column 6 erected so as to slide in the front-rear direction along the shaft guide rail 4, a spindle head 8 that slides up and down along the Y-axis guide rail 7 laid on the front surface of the column 6, and a spindle head 8 and an NC apparatus 10 for controlling various operations such as a sliding operation of the table 5 and the column 6 and a rotating operation of the main shaft 9.

  Further, a peripheral cover 11 is provided so as to surround the front and rear, left and right of the horizontal machining center 1 and the upper portions of both front and rear ends. Further, a first ceiling cover 13 that can be expanded and contracted in the front-rear direction is provided at the front portion of the peripheral cover 7, and expands and contracts as the column 6 slides in the front-rear direction, and a space (front space from the column 6 ( A so-called machining space (A1) in which the table 5 and the spindle 9 are installed is covered. In addition, a second ceiling cover 14 that can be expanded and contracted in the front-rear direction is provided at the rear part of the peripheral cover 7, and expands and contracts as the column 6 slides in the front-rear direction, and the space behind the column 6 ( A so-called column 6 moving space) A2 is covered. Then, by covering the horizontal machining center 1 as a whole with the surrounding cover 11, the first ceiling cover 13, and the second ceiling cover 14, the influence of room temperature change and air conditioning on the temperature change of the structure such as the bed 2 and the column 6 etc. We are trying to suppress this. Reference numeral 12 denotes a moving cover that is attached to both the left and right sides of the column 6 and slides in the front-rear direction together with the column 6 according to the sliding of the column 6. The movable covers 12, 12 partition a space A 1 ahead of the column 6 and a space A 2 behind the column 6. Further, although the space A2 is covered by the peripheral cover 11 and the second ceiling cover 14, it is not hermetically sealed, and air can move between the inside and outside of the covers 11 and 14.

  Furthermore, an air entrance / exit space 16 is formed by partitioning the lower side of the space 15 existing inside the bed 2, and a space A <b> 2 behind the air entrance / exit space 16 and the column 6 on the rear surface of the peripheral cover 11. Is provided with a duct 17 that communicates with each other. Therefore, when the drive device 18 operates and the column 6 reciprocates in the front-rear direction under the control of the NC device 10, the volume of the space A2 increases or decreases, so that positive / negative pressure is instantaneously generated in the space A2. As a result, the air moves inside and outside the surrounding cover 11 and the second ceiling cover 14, and the air in the air access space 16 is also exchanged through the duct 17.

  In addition, the temperature sensor ch1 that measures the temperature of the upper part of the bed 2 (above the air entrance / exit space 16), the temperature sensor ch2 that measures the temperature of the lower part of the bed 2 (below the air entrance / exit space 16), and the space A2 A temperature sensor ch3 that measures the ambient temperature in the vicinity of the installation position of the temperature sensor ch1 and a temperature sensor ch4 that measures the ambient temperature in the vicinity of the installation position of the temperature sensor ch2 in the air access space 16 are installed. Further, the temperature measurement device 21 that converts the analog signals output from the temperature sensors ch1 to ch4 into digital signals and digitizes them, and the temperature difference and temperature time based on the temperature measurement values digitized by the temperature measurement device 21. A temperature calculation device 22 that calculates a change in temperature (hereinafter referred to as a temperature change), and a determination device 23 that executes control as described later based on the calculation result of the temperature calculation device 22.

Here, control related to suppression of thermal deformation in the horizontal machining center 1 which is a main part of the present invention will be described based on flowcharts shown in FIGS. 4 and 5 and graphs shown in FIGS.
The following processes S1 to S25 executed by the temperature measurement device 21, the temperature calculation device 22, and the determination device 23 are repeatedly executed at predetermined processing intervals Δt (for example, 30 minutes) preset by the operator. Shall. Further, by a preliminary test or analysis, the temperature time constant τ1 of the upper part of the bed 2 where the temperature sensor ch1 is installed, the temperature time constant τ2 of the lower part of the bed 2 where the temperature sensor ch2 is installed, the upper and lower parts of the bed 2 It is assumed that the relationship between the temperature change difference and the machining accuracy is obtained in advance and set in the determination device 23 and the like. Furthermore, since the limit value Tmax of the temperature change difference between the upper part and the lower part of the bed 2 can be easily calculated from the processing accuracy set by the operator (required by the operator), It shall be set as a table.

  Then, as shown in FIG. 5, for example, if the operation of the horizontal machining center 1 is started at 8 am, first, the temperature T1 of the upper part of the bed 2 and the bed 2 are detected using the temperature sensors ch1 to ch4 and the temperature measuring device 21. The temperature T2 of the lower part of the bed, the ambient temperature T3 of the upper part of the bed 2, and the ambient temperature T4 of the lower part of the bed 2 are measured (S1), and ON / OFF of the determination flag that is turned on due to the conditions described later is confirmed. (S2). And of course, since it is OFF in the first confirmation at the time of operation start (it is judged as NO by S2), in temperature calculator 22, initial temperature difference Ts between the upper part of bed 2 and the lower part is expressed by the following formula (1). (S3).

  Further, using the temperatures T1 to T4 measured in S1 and the temperature time constants τ1 and τ2, the estimated temperature change Tu (t) at the upper part of the bed 2 as a function of the time t as shown in the following equation (2). And an estimated temperature change Td (t) in the lower part of the bed 2 as a function of time t as shown in the following equation (3) is obtained in association with time, and both estimated temperature changes Tu (t), Td (t) From this, a difference ΔT (t) of the estimated temperature change between the upper part and the lower part of the bed 2 as a function of the time t as shown in the following equation (4) is obtained in association with the time (S4).

  Then, the determination device 23 compares the estimated temperature change difference ΔT (t) with the temperature change difference limit value Tmax satisfying the machining accuracy preset by the operator (S5), and in the future, the estimated temperature change. If it is determined that there will be no situation where the difference ΔT (t) exceeds the limit value Tmax (NO in S5), the processing continuation determination (S11) is performed, and after the processing interval Δt from this processing (here Then, the temperature measurement (S1) is performed again at 8:30 am. In this situation, the second process is performed as the first process. In S3, the temperatures T1 ′ to T4 ′ measured in the second process are set as temperatures T1 to T4, and the temperatures T1 to T4 are used. Is stored as an initial temperature difference Ts. In S4, functions Tu (t), Td (t), and ΔT (t) are newly obtained using the temperatures T1 to T4 measured in the second processing, and the comparison with Tmax is performed again in S5. Do. The same applies to the third and subsequent processing.

  On the other hand, as shown in FIG. 6, for example, if it is determined that a difference ΔT (t) of the estimated temperature change will exceed the limit value Tmax in the future (YES in S5), the determination device 23 determines the current tn (here Then, whether or not the difference ΔT (t) in the estimated temperature change exceeds the limit value Tmax from the time n = 1) until the processing interval Δt elapses, that is, whether Δt> tmax−tn is satisfied. Is determined (S6). Then, as a result of the determination in S6, if it is determined that the time tmax has not been reached even if the processing interval Δt has elapsed (NO in S6), the determination flag is turned on (S7), and then the determination to continue processing (S11) is made. Go back to S1. Therefore, in the second and subsequent processes, the determination result in S2 is YES, and the process proceeds to S21 described later.

  On the other hand, as a result of the determination in S6, if it is determined that the time tmax is reached before the processing interval Δt elapses (YES in S6), the driving device 18 is operated via the NC device 10 to move the column 6 back and forth. By reciprocating in the direction (S8), the air in the space A2 and the air inlet / outlet space 16 is exchanged so that a large difference in estimated temperature change does not occur between the upper part and the lower part of the bed 2. Further, the determination device 23 determines the end of the reciprocating movement (S9), and if it is determined to be the end (YES in S9), the reciprocating movement of the column 6 is stopped (S10), and then the process continuation determination ( Perform S11) and return to S1. The end of reciprocation in S9 is determined by appropriately measuring the ambient temperature T3 at the upper part of the bed 2 and the ambient temperature T4 at the lower part of the bed 2 as the column 6 starts to reciprocate. Whether or not the difference from T4 has converged to a predetermined ambient temperature limit value ΔTc or less (the following equation (5)), the difference between the ambient temperature T3 and the ambient temperature T4 is equal to or less than a predetermined ambient temperature limit value ΔTc. It is judged that the process is over when it has converged. Since the determination flag is not turned ON at this time, in the second processing after the processing interval Δt, as described above, the second processing is processed as the first processing, and in S3, the measurement is performed in the second processing. The temperatures T1 ′ to T4 ′ are defined as temperatures T1 to T4, and the temperature difference calculated using the temperatures T1 to T4 is stored as the initial temperature difference Ts. In S4, the temperature T1 measured during the second process is stored. Using ~ T4, new functions Tu (t), Td (t), and ΔT (t) are obtained, and compared with Tmax again in S5.

  Next, when the determination flag is turned on in S7, in the second process (for example, the process executed at 8:30 am if the determination flag is turned on in the process executed at 8 am), the temperature T1 is set. It becomes YES by the determination in S2 after measuring “˜T4” (S1). Therefore, the process proceeds to S21, and the temperature calculation device 22 calculates the current temperature difference Ts' by the following equation (6). Further, using the temperatures T1 ′ to T4 ′ and the temperature time constants τ1 and τ2, the estimated temperature change Tu ′ (t) at the upper part of the bed 2 as a function of the time t as shown in the following equation (7): The estimated temperature change Td ′ (t) in the lower part of the bed 2 as a function of the time t as shown in the following equation (8) is obtained in association with the time, and the initial temperature difference Ts and the current temperature difference Ts ′. And the difference ΔT ′ (t of the estimated temperature change between the upper part and the lower part of the bed 2 as a function of the time t as shown in the following equation (9) from the estimated temperature changes Tu ′ (t) and Td ′ (t). ) In association with the time. That is, in the second and subsequent processes, the initial temperature difference Ts calculated in the first process (in other words, the machine state at the start of operation) is taken into consideration, and as shown in FIGS. Changes in the actual temperature difference between the upper part and the lower part (difference between the initial temperature difference Ts and the current temperature difference Ts ′) are added.

  Thereafter, whether or not the determination device 23 reaches a time tmax ′ at which the difference ΔT ′ (t) in the estimated temperature change exceeds the limit value Tmax before the processing interval Δt elapses from the current time tn (here, n ≧ 2). That is, it is determined whether or not Δt> tmax′−tn (S22). As a result of the determination in S22, for example, as shown in FIG. 7, if it is determined that the time tmax 'will not be reached even if the processing interval Δt has elapsed (NO in S22), the process proceeds to S11, and the determination to continue the process is made. Do. On the other hand, as a result of the determination in S22, for example, if it is determined that time tmax ′ is reached (YES in S22) before the processing interval Δt elapses as shown in FIG. Is operated to reciprocate the column 6 back and forth (S23), so that the air in the space A2 and the air inlet / outlet space 16 is exchanged, and there is no significant difference in the estimated temperature change between the upper part and the lower part of the bed 2. The state is as follows. Further, the determination device 23 determines the end of the reciprocating movement (S24), and if it is determined to be the end (YES in S24), the reciprocating movement of the column 6 is stopped (S25), and then the determination to continue the process ( S11) is performed. Then, the determination of the end of the reciprocating movement in S24 is made in the same manner as in S9 above. (The following equation (10)), and it is determined that the process is finished when the difference between the ambient temperature T3 ′ and the ambient temperature T4 ′ has converged to a predetermined ambient temperature limit value ΔTc or less. In addition, when the reciprocating movement of the column 6 is started, if the machining is being performed in the horizontal machining center 1, the machining may be stopped and then started. Then, when it is determined that the processing is not continued in S11 when the processing is finished, the control related to suppression of thermal deformation is also finished.

  According to the horizontal machining center 1 that executes the control as described above, the air entrance / exit space 16 is formed by partitioning the lower side of the space 15 existing inside the bed 2, and the air entrance / exit space 16 and the column 6 are formed. A duct 17 that communicates with the rear space A2 is provided, and the air in the space A2 and the air in / out space 16 can be exchanged by reciprocating the column 6 in the front-rear direction. And the temperature of the upper part of the bed 2 (above the air entrance / exit space 16), the temperature of the lower part of the bed 2 (below the air entrance / exit space 16), the ambient temperature in the vicinity of the position where the temperature sensor ch1 is installed in the space A2, and While measuring the ambient temperature in the vicinity of the installation position of the temperature sensor ch2 in the air inlet / outlet space 16 respectively, the difference ΔT (t), ΔT ′ (t) of the estimated temperature change between the upper part and the lower part of the bed 2 is calculated. Before the estimated temperature change differences ΔT (t) and ΔT ′ (t) exceed the limit value Tmax, the column 6 is reciprocated in the front-rear direction, and the air in the space A2 and the air inlet / outlet space 16 is replaced. The upper and lower portions of 2 are in such a state that there is no significant difference in estimated temperature change. Therefore, it is possible to suppress thermal deformation such as warpage or inclination generated in the bed 2 due to the difference in estimated temperature change, and it is possible to realize highly accurate machining. In addition, since a peripheral device is not required separately as in the prior art, not only the manufacturing cost but also the running cost can be kept low, and the number of devices that need to operate normally can be reduced. be able to. In addition, since the column 6 is reciprocated when it is determined that the difference ΔT (t), ΔT ′ (t) in the estimated temperature change exceeds the limit value Tmax during the processing interval Δt, the difference ΔT in the estimated temperature change The column 6 is reciprocated at the latest timing when (t) and ΔT ′ (t) are likely to exceed the limit value Tmax. Therefore, the column 6 is not reciprocated more than necessary, and the number of machining interruptions associated with the reciprocating movement of the column 6 can be suppressed, that is, the reduction in machining efficiency can be suppressed.

In addition, after the second processing, the estimated temperature change difference ΔT ′ (t) is calculated taking into account the machine state at the start of operation of the horizontal machining center 1, so that stable machining is possible without depending on the initial state. It becomes.
Further, the reciprocation of the column 6 is completed based on the comparison between the difference between the ambient temperature T3, T3 ′ at the upper part of the bed 2 and the ambient temperature T4, T4 ′ at the lower part of the bed 2 and a predetermined ambient temperature limit value ΔTc. Therefore, the thermal deformation can be reliably suppressed, that is, the estimated temperature change between the upper part and the lower part of the bed 2 is not greatly changed, and the column 6 is unnecessarily long. Without reciprocating, the processing interruption time can be minimized and the processing efficiency can be improved.

  Note that the machine tool according to the present invention is not limited to the aspect of the embodiment described above, and the overall configuration of the machine tool, the configuration related to control of thermal deformation, and the like do not depart from the spirit of the present invention. Thus, it can be changed as necessary.

  For example, in the above embodiment, the air access space 16 is formed by partitioning the lower side of the space 15 existing inside the bed 2, but a sheet metal or the like is used between the lower surface of the bed 2 and the floor surface. It is also possible to form an air in / out space or to form an air in / out space using a sheet metal or the like at the lower part of the side surface of the bed 2. Further, when the duct 17 is provided, there is no problem even if the duct 17 is provided separately from the surrounding cover 11.

  In the above embodiment, in the control for determining whether or not the column 6 is reciprocated, the difference ΔT (t) in the estimated temperature change is compared with the limit value Tmax, or from the current time tn to the time tmax, Although the time until tmax ′ is compared with the processing interval Δt, the temperature of the bed 2 and the temperature of the space A2 and the like are steadily increasing by continuing operation with a general machine tool (natural In the above formulas (2), (3), (7), and (8), t = Δt, and estimated temperature change differences ΔT, ΔT ′ at the next processing time The limit value Tmax may be compared (determined not at the entire curve of FIGS. 6 to 8 but at each processing time point). In other words, in the first process, as shown in FIG. 9, after executing S4, the estimated temperature change difference ΔT after the process interval Δt (during the second process) is compared with the limit value Tmax (S31). ). If it is determined that the difference ΔT in estimated temperature change after the processing interval Δt does not exceed the limit value Tmax (NO in S31), the determination flag is set to ON (S7), and the process proceeds to S11, while the estimation after the processing interval Δt is performed. When it is determined that the temperature change difference ΔT exceeds the limit value Tmax (YES in S31), the column 6 starts to reciprocate (S8). In the second and subsequent processes, as shown in FIG. 10, after executing S21, the difference ΔT ′ of the estimated temperature change after the processing interval Δt from the current time is compared with the limit value Tmax (S32). When it is determined that the estimated temperature change difference ΔT ′ after the processing interval Δt exceeds the limit value Tmax (YES in S32), the column 6 starts to reciprocate (S23). It becomes composition.

Furthermore, since the environment may change significantly due to air conditioning or the like during the processing interval Δt, the difference ΔT ′ (t) in the estimated temperature change between S21 and S22 in the above embodiment, similar to S5. It is also possible to perform the control so that the process proceeds to S22 only when it is determined that the estimated temperature change difference ΔT ′ (t) exceeds the limit value Tmax in the future.
Furthermore, in the above embodiment, the time is adopted, but it is also possible to execute the same control only by the time from the start of operation. In addition, in the above embodiment, the column 6 is configured to reciprocate when it is determined that the difference ΔT (t), ΔT ′ (t) between the estimated temperature changes exceeds the limit value Tmax during the processing interval. However, the estimated temperature change does not occur during the processing interval but before the predetermined time elapses beyond the processing interval (for example, until 1 hour elapses beyond the processing interval or processing is completed). If it is determined that the differences ΔT (t) and ΔT ′ (t) exceed the limit value Tmax, the column 6 can be configured to reciprocate. And by employ | adopting the said structure, the column 6 can be reciprocated at an early timing, and the thermal deformation resulting from the difference in estimated temperature change can be suppressed further.

In the above-described embodiment, the reciprocation of the column 6 causes the difference between the ambient temperature T3, T3 ′ at the upper part of the bed 2 and the ambient temperature T4, T4 ′ at the lower part of the bed 2 to be within a predetermined ambient temperature limit value ΔTc. For example, the number of reciprocations and the reciprocation time of the column 6 are set in advance, and the reciprocation of the column 6 is terminated based on the number of reciprocations and the reciprocation time. It is also possible to configure.
Further, in the above embodiment, the determination flag is set to ON when it is determined NO in S6. However, the determination flag is set to ON between S5 and S6, that is, the difference in estimated temperature change in the future. If it is determined that a situation where ΔT (t) exceeds the limit value Tmax occurs, there is no problem even if the determination flag is turned on regardless of whether the column 6 is reciprocated.

Furthermore, when it is determined NO in S5, that is, when it is determined that a situation where the estimated temperature change difference ΔT (t) will not exceed the limit value Tmax will not occur in the future, the processing interval Δt is set to a longer time ( For example, control is performed such that the processing interval Δt is changed in accordance with the determination result in S5 such that the processing interval Δt is returned to the original length when the determination in S5 becomes YES. It is also possible to execute.
Furthermore, in the above embodiment, when NO is determined in S5, ΔT (t) is compared with the limit value Tmax in the next processing, but NO is determined in S5. In this case, the determination flag may be turned on, and ΔT ′ (t) may be compared with the limit value Tmax in the subsequent processing.
In addition, although the horizontal machining center has been described in the above embodiment, the present invention can be applied to other machine tools as long as the column can reciprocate in a predetermined direction with respect to the bed.

  1 .... Horizontal machining center, 2 .... Bed, 4 .... Z-axis guide rail, 6 .... Column, 10 .... NC device (control device), 11 .... Surrounding cover (cover body), 12 .... Moving cover ( Cover body), 13 .... first ceiling cover, 14..second ceiling cover (cover body), 18..air inlet / outlet space, 17..duct, 18..drive device, 21..temperature measuring device (first) 1 to 4th temperature measuring means), 22 .... temperature computing device (control device), 23 ... determining device (control device), ch1 ... temperature sensor (first temperature measuring means), ch2 .... temperature sensor (first) 2 temperature measuring means), ch3 ... temperature sensor (third temperature measuring means), ch4 ... temperature sensor (fourth temperature measuring means), A1 ... space (working space), A2 ... space (moving space).

Claims (3)

A bed and a column that is slidable in a predetermined direction on the bed, and a space on one side of the column in the sliding direction of the column is a processing space, and a space on the other side is the column. A machine tool that is a moving space, and at least the moving space is covered with a cover body,
While providing an air entrance / exit space through which air can enter and exit the bed, the air entrance / exit space communicates with the moving space,
A first temperature measuring means for measuring a temperature above the air entrance / exit space in the bed, a second temperature measuring means for measuring a temperature below the air entrance / exit space in the bed, and a surrounding in the moving space A third temperature measuring means for measuring temperature, a fourth temperature measuring means for measuring the ambient temperature in the air inlet / outlet space, and a reciprocating movement of the column based on the measured values by the first to fourth temperature measuring means. And a control device for controlling
The control device calculates an estimated temperature change in the upper part of the bed and an estimated temperature change in the lower part of the bed based on the measurement values obtained by the first to fourth temperature measuring units at a predetermined processing interval. At the same time, based on both estimated temperature changes, the difference in estimated temperature changes between the upper and lower parts of the bed is calculated.
When it is determined that the difference in the estimated temperature change exceeds a predetermined limit value during the processing interval, the column is reciprocated, and the air in the moving space and the air in / out space is switched. Machine Tools. A bed and a column that is slidable in a predetermined direction on the bed, and a space on one side of the column in the sliding direction of the column is a processing space, and a space on the other side is the column. A machine tool that is a moving space, and at least the moving space is covered with a cover body,
While providing an air entrance / exit space through which air can enter and exit the bed, the air entrance / exit space communicates with the moving space,
A first temperature measuring means for measuring a temperature above the air entrance / exit space in the bed, a second temperature measuring means for measuring a temperature below the air entrance / exit space in the bed, and a surrounding in the moving space A third temperature measuring means for measuring temperature, a fourth temperature measuring means for measuring the ambient temperature in the air inlet / outlet space, and a reciprocating movement of the column based on the measured values by the first to fourth temperature measuring means. And a control device for controlling
The control device calculates an estimated temperature change in the upper part of the bed and an estimated temperature change in the lower part of the bed based on the measurement values obtained by the first to fourth temperature measuring units at a predetermined processing interval. At the same time, based on both estimated temperature changes, the difference in estimated temperature changes between the upper and lower parts of the bed is calculated.
If it is determined that the difference in estimated temperature change exceeds a predetermined limit before a predetermined time elapses beyond the processing interval, the column is reciprocated to move the air in the moving space and the air in / out space. Machine tool characterized by replacing   Whether the difference between the measured value by the third temperature measuring means and the measured value by the fourth temperature measuring means has converged to a predetermined ambient temperature limit value or less with the start of reciprocation of the column. 3. The machine tool according to claim 1, wherein the reciprocation of the column is stopped when the difference is converged to be equal to or less than the predetermined ambient temperature limit value.

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