JP2009142919A - Temperature controller for machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature controller for a machine tool, capable of carrying out temperature control in various modes by bi-directionally sending/receiving data to/from the machine tool while greatly increasing a degree of freedom in communication information between the machine tool and the temperature controller to meet various needs for temperature control. <P>SOLUTION: The temperature controller comprises a bi-directional communication interface 15 for receiving instruction data from the machine tool 30 and sending response data responding to the instruction data, a communication data processing part 14 for analyzing the contents of the instruction data, creating the response data to the instruction data, and sending it through the bi-directional communication interface, a cooling circuit 2 for circulating heat medium liquid into the machine tool, and temperature control means 10, 11 for controlling the temperature of the heat medium liquid to be circulated in the cooling circuit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a temperature control device for a machine tool that suppresses thermal deformation by controlling the temperature of a heat medium liquid to be circulated through the machine tool. The present invention relates to a temperature control device for a machine tool capable of responding to various needs and performing various forms of temperature control.

  The machine tool body deforms due to environmental temperature, heat from the heat generating part, and the like. Since the deformation of the airframe affects the processing accuracy, conventionally, the temperature of each part of the airframe has been controlled to a constant temperature. Various methods of temperature control have been proposed, but a constant flow-controlled cooling oil that is normally temperature-controlled is always supplied to the heat generating part of the machine tool to cool the heat generating part. This cooling oil is cooled by the refrigerant through the heat exchanger.

  Such exchange of information (signals) between the temperature control device and the machine tool is normally sent from the machine tool to the temperature control device or from the temperature control device to the machine tool. Only normal / abnormal signals. These signals are sent through a dedicated signal line.

In addition, as a technique for improving the accuracy of temperature control of a machine tool, a technique such as the following Patent Document 1 has already been proposed by the inventors of the present invention. Patent Document 1 describes a temperature control method for a machine tool in which a transient deviation and a steady deviation are reduced by feedforward control. In such feedforward control, information on the rotational speed of the spindle of the machine tool is sent to the temperature control device. A dedicated signal line is also required for information for feedforward control.
Japanese Patent No. 2529905

  In a conventional temperature control device, a start / stop signal for the temperature control device and a normal / abnormal signal from the temperature control device are exchanged via a dedicated signal line. Furthermore, when feedforward control as in Patent Document 1 is performed, or when new information (signals) is required to be exchanged due to other needs, a dedicated signal line or interface circuit is also provided for the information. It becomes necessary. As described above, in the conventional temperature control device, the type of information exchanged with the machine tool is almost fixed, and it is difficult to cope with the need for new information exchange. Met.

  Furthermore, with the high precision and diversification of machining, various new functions have been required for temperature control devices for machine tools. For example, in order to shorten the warm-up operation time at the start of the machine tool and improve the operating rate, it is required to perform special temperature control different from that at the normal operation at the start of the machine tool. In addition, the control parameters of the temperature control device can be changed as appropriate according to the operating state of the machine tool, and the temperature and operating state of each part of the temperature control device can be monitored to ensure the machining accuracy of the machine tool even during long-time machining. It is requested to do. Further, it is conceivable to temporarily perform feedforward control according to the operating state of the machine tool to shorten the response time of temperature control. It has been difficult for conventional temperature control devices to meet such diverse needs.

  Therefore, the present invention enables bidirectional data transmission / reception with the machine tool, greatly expands the degree of freedom of communication information between the machine tool and the temperature control device, and responds to various needs for temperature control, An object of the present invention is to provide a temperature control device for a machine tool capable of performing various forms of temperature control.

  In order to achieve the above object, a temperature control device for a machine tool according to the present invention receives command data from a machine tool and transmits response data to the command data, and the command data. The communication data processing unit that analyzes the contents of the command data and generates response data for the command data and transmits the response data via the bidirectional communication interface, the cooling circuit that circulates the heat medium liquid to the machine tool, and the cooling circuit And a temperature control means for controlling the temperature of the circulating heat medium liquid.

  In the temperature control device for a machine tool, it is preferable that the command data includes a command for requesting the temperature control device by designating a type of information.

  In the temperature control device for a machine tool, it is preferable that the command data includes an identifier for designating a type of information.

  In the temperature control device for a machine tool, the identifier can specify various temperature measurement values, set temperature of the heat transfer medium, operation / stop state of the temperature control device, temperature control parameters, and various alarm information. It is preferable.

  In the temperature control device for a machine tool, the command data preferably includes a command for specifying a type of information and setting a value and a state to the temperature control device.

  In the temperature control device for a machine tool, the response data preferably includes an identifier for designating a type of information.

  Since this invention is comprised as mentioned above, there exist the following effects.

  By providing a two-way communication interface, it is possible to send and receive data to and from the machine tool, greatly expanding the degree of freedom of communication information between the machine tool and the temperature control device, and meet various needs for temperature control. In response to this, various forms of temperature control can be implemented. Various statuses of the temperature control device can be read from the machine tool side, the status of the temperature control device can be changed, and various parameter settings can be changed. It is also possible to change the temperature control mode, and the degree of freedom in the control mode of the temperature control is drastically improved.

  Since the command data from the machine tool includes a command for requesting the temperature control device by specifying the type of information, various states and values of the temperature control device can be read, and the state of the temperature control device can be changed. It is possible to grasp accurately and in detail.

  The command data from the machine tool includes commands to specify the type of information for the temperature control device and set the value and status, so the temperature control device status change and various parameter setting changes can be performed automatically Thus, the degree of freedom in the control mode of temperature control is dramatically improved.

  Since the response data includes an identifier for designating the type of information, the machine tool can confirm whether or not the type of the response data matches that requested by this identifier.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a state in which the temperature control device 1 of the present invention is connected to a machine tool 30. The machine tool 30 includes a machine tool body 31 that actually performs machining and an NC (numerical control) device 32 for controlling the machine tool body 31. The spindle head is a typical heat source for machine tools. A spindle is rotatably supported on the spindle head, and a tool or a workpiece is attached to the spindle and is driven to rotate.

  Since the rotation speed of the spindle fluctuates from a stopped state to several thousand revolutions per minute, the spindle head supporting the spindle is cooled to control the temperature, and the spindle head temperature is always constant with respect to the reference temperature. Keep the temperature difference. That is, the control target is to keep the temperature of the spindle head at a constant temperature difference with respect to the reference temperature. However, the constant temperature difference in this case includes the case where the temperatures are equal (temperature difference 0).

  The reference temperature is generally set to a room temperature or a temperature of a member (for example, a bed or a column) having a large time constant (a large heat capacity) in a component of the machine tool. The temperature of the reference part measured by the reference temperature sensor 33 is set as the reference temperature. The reference temperature may be selected from among the temperatures measured at a plurality of positions, or an average value of a plurality of measured values may be used as the reference temperature. Moreover, it is good also as a reference temperature by giving an appropriate calculation to a measured value.

  In FIG. 1, the cooling circuit 2 is circulated so as to cool the spindle head and the like of the machine tool 30. That is, the cooling circuit 2 coming out of the temperature control device 1 is arranged so as to circulate through the spindle head of the machine tool and return to the temperature control device 1 again. In the cooling circuit 2, cooling oil is circulated as a heat medium liquid. The cooling oil is cooled by the temperature adjusting unit 10 of the temperature control device 1, adjusted and controlled so as to have a constant temperature, and sent to the machine tool 30.

  The temperature control device 1 includes a temperature adjustment unit 10 for cooling the cooling oil and a temperature control unit 11 for controlling the temperature adjustment unit 10. Note that the temperature control means in the present invention corresponds to a combination of both the temperature adjustment unit 10 and the temperature control unit 11. The configuration of the temperature adjustment unit 10 will be described in detail later. In addition, the temperature control apparatus 1 is provided with a bidirectional communication interface 15 for exchanging information with the machine tool 30 bidirectionally.

  A bidirectional communication interface is also provided on the NC device 32 side of the machine tool 30, and the machine tool 30 and the temperature control device 1 can transmit and receive information bidirectionally via these interfaces. is there. That is, command data from the machine tool 30 to the temperature control device 1 is received via the bidirectional communication interface 15, and response data and transmission data for the command data are also transmitted via the bidirectional communication interface 15.

  The communication data processing unit 14 processes data transmitted / received via the bidirectional communication interface 15. The communication data processing unit 14 analyzes the content of the command data from the machine tool 30 and rewrites the data stored in the internal memory of the temperature control unit 11 according to the command data, if necessary. Further, the contents of the data stored in the internal memory of the temperature control unit 11 are read according to the command data, response data for the command data is created and transmitted to the machine tool 30 via the bidirectional communication interface 15. The communication data processing unit 14 is disposed between the bidirectional communication interface 15 and the temperature control unit 11.

  FIG. 2 is a diagram illustrating an overall configuration of the temperature control apparatus 1. The temperature adjusting unit 10 in FIG. 1 comprehensively shows the refrigerator 5, the condenser 6, the expansion valve 7, the heat exchanger 8, and the like in FIG. A cooling pump 22 provided in the cooling circuit 2 is driven by a drive motor 23 to circulate the cooling oil in the cooling circuit 2 at a constant flow rate. The cooling oil is cooled by the heat exchanger 8, and then flows into the spindle head to cool the spindle head. The cooling oil after cooling the spindle head returns to the cooling pump 22 through the cooling circuit 2.

  The temperature (return oil temperature) of the cooling oil after cooling the spindle head is detected by the temperature sensor 21, and feedback control is performed so that the return oil temperature becomes the set temperature. The set temperature is set to a value having a certain temperature difference from the reference temperature. The temperature difference may be 0. In this case, the set temperature is equal to the reference temperature. The temperature sensor 21 is not limited to the illustrated position, and may be disposed at any position as long as the return oil temperature can be detected. For example, it may be arranged on the inflow side of the cooling pump 22.

  On the other hand, regarding the refrigerant flowing into the heat exchanger 8, first, the refrigerant gas is compressed by the refrigerator 5 and sent to the condenser 6. In the condenser 6, the heat of the refrigerant gas that has been compressed and has risen in temperature is radiated and liquefied. The condenser 6 is cooled by air cooling by a cooling fan 61. The liquefied refrigerant gas is further squeezed and expanded when passing through the expansion valve 7 to be in a low-temperature and low-pressure gas-liquid mixed state. This low-temperature and low-pressure gas-liquid mixed refrigerant gas flows into the heat exchanger 8 to cool the cooling oil. The refrigerant gas takes the heat of the cooling oil in the heat exchanger 8 and vaporizes, and efficiently cools the cooling oil by the heat of vaporization. The refrigerant gas flowing out from the heat exchanger 8 returns to the refrigerator 5 and circulates in the circulation circuit 3.

  The refrigerator 5 is driven by, for example, an inverter control drive device. In that case, the rotation speed of the refrigerator 5 can be continuously changed and controlled, and the cooling capacity of the refrigerator 5 can be changed and controlled continuously. The refrigerator 5 may be driven at a constant rotational speed by a normal AC power source. When the refrigerator 5 is driven at a constant rotational speed, an inverter control drive device is not required, and the cost of the temperature control device 1 can be reduced and the temperature control device 1 can be downsized. In this case, the cooling capacity of the refrigerator 5 is adjusted by the opening degree of the expansion valve 7 and the opening degree of the bypass valve 9.

  In the circulation circuit 3 in which the refrigerant gas from the refrigerator 5 circulates, a bypass path 4 is provided for allowing a part of the refrigerant gas that has been compressed to rise in temperature to flow into the heat exchanger 8 without being cooled. The bypass passage 4 is provided with a bypass valve 9 which is a flow rate adjusting valve. The bypass 4 is provided to reduce and adjust the cooling capacity for cooling the cooling oil. When the bypass valve 9 is in the open state, the high temperature gas is mixed with the low temperature refrigerant gas and flows into the heat exchanger 8, so that the cooling capacity is reduced. By changing and controlling the opening degree of the bypass valve 9, the cooling capacity can be changed and controlled. When the bypass valve 9 is fully closed, the high temperature gas is not mixed, and the cooling capacity of the refrigerator 5 is maximized.

  The temperature controller 11 controls the cooling oil temperature by controlling the rotational speed of the refrigerator 5, the opening degree of the expansion valve 7, and the opening degree of the bypass valve 9. A display unit 12 and an input unit 13 are connected to the temperature control unit 11. Various parameters relating to temperature control can be confirmed by the display unit 12, and these parameters can be input by the input unit 13. Further, the communication parameter of the bidirectional communication interface 15 can be confirmed and the setting can be changed by the display unit 12 and the input unit 13.

  The temperature control of the cooling oil performs feedback control so that the return oil temperature detected by the temperature sensor 21 becomes the set temperature. The feedback control is performed with high accuracy, high speed response and high stability by PID control. That is, feedback control is performed by changing and controlling the rotational speed of the refrigerator 5, the opening degree of the expansion valve 7, and the opening degree of the bypass valve 9 by PID control. In addition, the rotational speed of the refrigerator 5 and the opening degree of the expansion valve 7 can be simultaneously controlled in conjunction so as to have a one-to-one correspondence relationship. Moreover, the opening degree of the expansion valve 7 and the opening degree of the bypass valve 9 can be simultaneously controlled in conjunction so as to have a one-to-one relationship.

  FIG. 3 is a diagram illustrating an example of a bidirectional communication protocol performed between the temperature control device 1 and the machine tool 30. The bidirectional communication interface 15 may perform communication using serial data (data transmitted / received bit by bit in time series) or may perform communication using parallel data (data transmitting / receiving a plurality of bits simultaneously in time series). Good. Here, a case of bidirectional communication using serial data will be described. As an actual interface circuit, a serial interface circuit such as a so-called RS-232C or a network interface circuit such as Ethernet (registered trademark) for LAN can be used.

  For example, when RS-232C is used, communication parameters such as communication speed, communication data configuration (data length, parity presence / absence, stop bit length, etc.) can be confirmed and changed by the display unit 12 and the input unit 13. it can. FIG. 3A shows a case where polling is performed from the machine tool 30 to the specific temperature control device 1. The polling is an operation for requesting the temperature control device 1 connected to the machine tool 30 to transmit designated data. This is performed when the designated data is read from the temperature control device 1.

  As shown in FIG. 3A, the machine tool 30 side first transmits 2-byte device addresses A1 and A2, and then transmits 2-byte identifiers S1 and S2. Finally, a 1-byte “ENQ” character is transmitted. Device addresses A1 and A2 are addresses uniquely assigned to each device for specifying the temperature control device. Thus, even if a plurality of temperature control devices and other auxiliary devices are connected to the machine tool 30, they can be specified separately. The identifiers S1 and S2 indicate the type of requested data. The “ENQ” character is a transmission control character indicating the end of the polling procedure.

  When the temperature control device 1 receives a data sequence as shown in FIG. 3A indicating the polling procedure, if the device addresses A1 and A2 match their own addresses, the response data as shown in FIG. 3B. Send. The first “STX” character in FIG. 3B is a transmission control character indicating the start of transmission data. The next identifiers S1 and S2 indicate the type of data to be transmitted, and the machine tool 30 side can confirm whether or not the type of response data matches that requested. The next 6 bytes of data D1 to D6 are the contents of the response data indicated by the identifier.

  The next “ETX” character is a transmission control character indicating the end of transmission data. The next error detection codes B1 and B2 are data for error detection of the transmission data block, and are data indicating the horizontal parity (even number) from the identifier S1 to the “ETX” character. Based on the error detection codes B1 and B2, the machine tool 30 can determine the validity of the response data. When there is a transmission error or the like in the response data, it is possible to request retransmission of data from the machine tool 30 side.

  Further, the machine tool 30 side transmits an “ACK” character when the response data as shown in FIG. The “ACK” character is a transmission control character that means an acknowledgment. If the response data cannot be received normally, the machine tool 30 transmits a “NAK” character. The “NAK” character is a transmission control character that means a negative response. In this case, a response data retransmission request is made.

  When the “NAK” character is transmitted from the machine tool 30 side, the temperature control device 1 retransmits the response data. The case where the machine tool 30 cannot normally receive the response data is, for example, when an error is detected in the response data by an error detection code, or when the identifier is different from that requested, the structure of the response data (length or transmission control character) This is a case where the position of the) is abnormal.

  3C and 3D show a case where selecting is performed on the specific temperature control device 1 from the machine tool 30 side. Selecting is an operation of selecting a device as a communication partner from the machine tool 30 side. In the present invention, selecting is used when writing (setting) specified data in the temperature control apparatus 1. As shown in FIG. 3C, device addresses A1 and A2 for designating the temperature control device 1 are first transmitted from the machine tool 30 side. Subsequently, setting data for the temperature control device 1 as shown in FIG. 3D is sent from the machine tool 30 side.

  The configuration of the setting data in FIG. 3D is the same as that of the response data in FIG. The first “STX” character, identifiers S1, S2 indicating the type of setting data, setting data contents D1 to D6, “ETX” character, and error detection codes B1, B2 are sent in succession. The temperature control device 1 selected by selecting (device addresses A1 and A2 match) changes the setting by rewriting the internal data indicated by the identifiers S1 and S2 based on the setting data.

  Further, when the temperature control apparatus 1 has successfully received the setting data as shown in FIG. 3D, the temperature control apparatus 1 transmits an “ACK” character as an acknowledgment. If the setting data cannot be received normally, the temperature control device 1 transmits a negative “NAK” character. The case where the temperature control device 1 cannot normally receive the setting data means that, for example, when an error is detected in the setting data by an error detection code, or when the identifier does not exist in the table, the configuration of the setting data (length or transmission control character) In the case where the setting data is out of the setting range. When the “NAK” character is transmitted from the temperature control device 1, the machine tool 30 side can perform recovery processing such as selecting again.

  Through the bidirectional communication as described above, the state and internal data of the temperature control device 1 can be arbitrarily designated and read from the machine tool 30 side, and setting data can be written to the temperature control device 1 from the machine tool 30 side. You can also change the state or change the internal data. The data that can be read from and written to the temperature control device 1 is given an identifier that can identify each type. Data that can be read from and written to the temperature control device 1 can be, for example, the following data.

  As read-only data, the control mode, various temperature measurement values (master, slave, room temperature, body temperature, etc.), various alarm information, and the like can be read from the temperature control device 1. Data that can be read from and written to the temperature control device 1 includes a set temperature for temperature control, an operation amount (cooling amount: 0 to 100%), a PID setting parameter (0 to 10), an operation / stop state, and the like. As described above, data reading from the temperature control device 1 is performed by polling, and data writing to the temperature control device 1 is performed by selecting.

  As described above, since the various states of the temperature control device 1 can be read from the machine tool 30 side, the state of the temperature control device 1 can be changed, and various parameter settings can be changed by bidirectional communication. It is also possible to automatically change the form and control parameters from the machine tool 30 side, and the degree of freedom of the control form of temperature control is dramatically improved. For example, it is possible to easily execute feed forward control temporarily according to the operating state of the machine tool or monitor the temperature and operating state of each part of the temperature control device.

  Specifically, when the machine tool is started, the control parameter of the temperature control device 1 is set to a value different from the normal value so as to approach the steady temperature in a short time, and the warm-up operation time of the machine tool is shortened to operate. The rate can be improved. Also, when long-time machining is required, such as mold machining, the temperature and operating state of each part of the temperature control device are monitored, and if a problem occurs in the temperature control device, the machine tool is immediately By moving to an avoidance operation, it is possible to maintain the machining accuracy of an expensive mold and avoid a defective product.

  In the above description, the bidirectional communication interface performs communication using serial data. However, the present invention is not limited thereto, and communication may be performed using parallel data. Further, the data read / written to / from the temperature control device is not limited to the exemplified data, and other arbitrary data may be read / written.

  According to the present invention, bidirectional data transmission / reception with a machine tool is enabled, the degree of freedom of communication information between the machine tool and the temperature control device is greatly expanded, and it meets various needs for temperature control, A temperature control device capable of performing various forms of temperature control can be provided.

It is a figure which shows the state which connected the temperature control apparatus 1 of this invention with the machine tool. 1 is a diagram illustrating an overall configuration of a temperature control device 1. FIG. It is a figure which shows the example of a two-way communication protocol.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Temperature control apparatus 2 Cooling circuit 3 Circulation circuit 4 Bypass path 5 Refrigerator 6 Condenser 7 Expansion valve 8 Heat exchanger 9 Bypass valve 10 Temperature adjustment part 11 Temperature control part 12 Display part 13 Input part 14 Communication data processing part 15 Both Communication interface 21 Temperature sensor 22 Cooling pump 23 Drive motor 30 Machine tool 31 Machine tool body 32 NC device 33 Reference temperature sensor 61 Cooling fan

Claims (6)

A bidirectional communication interface (15) for receiving command data from the machine tool (30) and transmitting response data to the command data;
A communication data processing unit (14) that analyzes the content of the command data, creates response data for the command data, and transmits the response data via the bidirectional communication interface (15);
A cooling circuit (2) for circulating a heat medium liquid to the machine tool (30);
A temperature control device for a machine tool, comprising temperature control means (10, 11) for controlling the temperature of the heat medium liquid to be circulated in the cooling circuit (2). A temperature control device for a machine tool according to claim 1,
The command data includes a command for designating and requesting a type of information to the temperature control device. A temperature control device for a machine tool according to claim 2,
The command data is a temperature control device for a machine tool that includes an identifier for designating a type of information. A temperature control device for a machine tool according to claim 3,
The identifier is a temperature control device for a machine tool that can specify various measured temperature values, set temperature of the heat transfer medium, operation / stop state of the temperature control device, parameters related to temperature control, and various alarm information. A temperature control device for a machine tool according to any one of claims 1 to 4,
The command data is a temperature control device for a machine tool that includes a command for specifying a type of information and setting a value and a state to the temperature control device. A temperature control device for a machine tool according to any one of claims 1 to 5,
The response data is a temperature control device for a machine tool that includes an identifier for designating a type of information.

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