Machine tool with temperature control system
By employing an independent temperature control loop and control unit on the machine tool, combined with a heat source, a cold source, and a liquid-air heat exchanger, the problem of decreased accuracy of the machine tool in temperature fluctuation environments is solved, achieving high-precision temperature control and machining.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-08
- Publication Date
- 2026-03-31
AI Technical Summary
When machine tools are in non-air-conditioned rooms or environments with fluctuating temperatures, the geometric changes caused by changes in ambient temperature affect machining accuracy. Existing technologies cannot effectively control the temperature to meet the requirements of high-precision machining.
The machine tool with a temperature control system uses an independent temperature control loop and control unit to precisely control the temperature of each area of the machine tool. It uses a mixing valve, heat source and cold source to regulate the temperature, and combines a liquid-air heat exchanger and temperature sensor to achieve temperature stability in each area.
It enables high-precision machining of machine tools in temperature-fluctuating environments, reduces additional costs, simplifies the components of the temperature control system, and improves machining accuracy.
Smart Images
Figure CN121773003A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a machine tool having a temperature control system for cooling and / or heating areas of the machine tool. Background Technology
[0002] As precision requirements increase, geometric changes within machines caused by ambient temperature fluctuations at the machine's installation location are playing an increasingly significant role, especially when the machine tool is not operating in an air-conditioned room or a room with air conditioning, even if the room is air-conditioned, as temperatures can fluctuate. In most cases, the temperature constantness in air-conditioned rooms or machine rooms is no better than + / -1°C or even + / -2°C throughout the day. This has led to considerable heat-induced geometric changes within the machine, and consequently, undesirable machining inaccuracies, as the machine is exposed to varying temperatures throughout the day. Using new temperature control units, the temperature of different areas of the machine can be controlled very effectively, so that temperature fluctuations at the machine's installation location no longer, or almost no longer, affect the machine's geometry. Summary of the Invention
[0003] Therefore, the object of the present invention is to provide a machine tool for machining workpieces, which has a simple structure and simple, cost-effective manufacturability, and has the maximum possible temperature independence during machining in order to meet the highest accuracy requirements during machining.
[0004] This objective is achieved by a machine tool having the features of claim 1. The dependent claims illustrate other preferred modifications of the invention.
[0005] In contrast, the machine tool according to the invention for machining workpieces, having the features of claim 1, has the following advantages: The highest precision requirements during workpiece machining are made possible by means of an improved temperature control system. Therefore, ultra-precision machining of the workpiece can be achieved reliably. In this case, the temperature control system according to the invention requires relatively few and simple components and can be well integrated into the machine tool. As a result, the additional costs resulting from the temperature control system according to the invention can be kept low. Electrical components in the temperature control system, such as Peltier elements, can also be omitted.
[0006] The temperature control system according to the invention is configured for temperature control of various areas of a machine tool. These areas can be, for example, drives, worktables, beds, Z-columns, covers or housings, Z-axis with a spindle, working areas, etc. In this case, the temperature control system according to the invention can reliably and with the highest accuracy control the temperature of two components of the machine tool, as well as, for example, air-filled areas (such as the working area). Each area is temperature-controlled by a separate temperature control loop. The temperature control system includes a tank, a pump for delivering temperature-controlled fluid from the tank, and a temperature control loop for each area to be temperature-controlled. Each temperature control loop returns to the tank. Furthermore, the temperature control system includes branches in the lines connected to the pump. Additionally, the temperature control system includes a cold source, with the branches connected to the inlet of the cold source. In each temperature control loop of the temperature control system, a mixing valve is configured downstream of the branch and the cold source in the flow direction. Each mixing valve has a first inlet connected to the branch, a second inlet connected to the cold source, and an outlet connected to one of the temperature control loops. The mixing valve is configured, on the one hand, to mix the mixture of temperature-controlled fluid from the cold source and the tank, and on the other hand, to allow complete disconnection from either the cold source or the tank. The temperature control system also includes a control unit configured to set a predetermined setpoint temperature in each temperature control loop by means of a mixing valve.
[0007] The corresponding setpoint temperature depends on the actual temperature in the corresponding area of the machine tool. If the actual temperature in the considered area of the machine tool corresponds to the setpoint temperature, the mixing valve can also be completely closed by the control unit, so that temperature control is not performed on the area of the machine tool with the correct temperature.
[0008] If, during operation, the machine tool releases a relatively large amount of heat into the temperature control loop, the temperature-controlled fluid in the tank will heat up to a temperature higher than the maximum setpoint temperature of one of the temperature control loops. If this is a relatively rapid occurrence, the heat source in the temperature control system can be omitted.
[0009] Preferably, the heat source is located between the branch and the first inlet of the mixing valve. The heat source is configured to heat the temperature-controlled fluid supplied to the inlet of the mixing valve.
[0010] Alternatively or additionally, a heat source can be configured in the tank. Then, for example, before starting the machine tool, the temperature control fluid is heated to a level higher than the highest setpoint temperature of one of the temperature control loops. During machine tool operation, the heat source can then be shut off, as the returning heated temperature control fluid maintains a sufficiently high temperature in the tank.
[0011] More preferably, at least one temperature control loop directly controls the temperature of an area of the machine tool. This directly temperature-controlled area is preferably the machine tool bed or Z-column. In these areas of the machine tool, due to their size, there is sufficient installation space to integrate the heat exchanger with, for example, a meandering wiring section for the temperature control loop.
[0012] More preferably, a liquid-air heat exchanger is configured in at least one temperature control loop to control the temperature of at least one area of the machine tool using air. Using the liquid-air heat exchanger, for example, the air-filled area of the machine tool can be temperature-controlled. Preferably, in this case, the temperature-controlled area of the machine tool is the working area of the machine tool.
[0013] Particularly preferably, the air, temperature-controlled by a liquid-air heat exchanger, is used as barrier air in a predetermined area of the machine tool. This can be done, for example, at the Z-axis with the spindle, at a machining location used to blow away debris, or near an oil mist extraction zone to guide the oil mist in a predetermined direction.
[0014] According to another preferred embodiment of the invention, the temperature control system includes a plurality of temperature sensors. In this case, the temperature sensors may be directly configured in a section of the temperature control system and / or configured in an area of the machine tool to be temperature-controlled, in order to obtain information about the current temperature of the area to be temperature-controlled. Preferably, all temperature sensors are connected to a control unit of the temperature control system. The control unit is configured to set the setpoint temperature of each temperature control loop based on the temperature values detected via the temperature sensors.
[0015] More preferably, the heat source is a cylindrical heater. The cylindrical heater is preferably equipped with a power supply and capable of rapidly adjusting the temperature of the control fluid. The cylindrical heater is preferably integrated into the machine tool or into a separately installed temperature control unit. More preferably, the cold source is an internal refrigeration unit within the machine tool or the separately installed temperature control unit. Alternatively, the cold source is an external cold source. This could also be, for example, a cooling device installed in the ambient air outside the machine room, wherein the machine tool is equipped with a temperature control system according to the invention.
[0016] More preferably, the liquid-air heat exchanger is an air temperature control unit or a recirculation unit. The air temperature control unit can be constructed as a simple passive water-air heat exchanger, in which air is blown through the heat exchanger by means of a fan or the like, through which the temperature-controlled fluid flows. The recirculation unit can be used, for example, in the enclosure or housing of a machine tool, particularly when air isolation is not required or when extraction from the hollow space of the machine tool to be temperature-controlled is unnecessary. In this way, energy can be saved.
[0017] More preferably, the control unit of the temperature control system is configured such that the area to be temperature-controlled via a liquid-air heat exchanger is controlled first. Only subsequently, the area to be temperature-controlled via a direct temperature control loop is controlled. This is necessary because the temperature control of areas of the machine tool, such as the bed or other areas, directly temperature-controlled using a temperature-control fluid reaches the desired temperature significantly faster through heat conduction than in the case of air-based temperature control (e.g., in the machine tool's working area). Therefore, for energy reasons, priority temperature control of the areas to be temperature-controlled via the liquid-air heat exchanger is advantageous. Particularly preferably, in this case, the direct temperature control loop can be shut off by means of an additional shut-off valve.
[0018] According to another preferred embodiment of the invention, the control unit is configured to precisely operate the heat source such that the temperature of the temperature-controlled fluid leaving the heat source precisely corresponds to the highest setpoint temperature of the temperature control loop of the temperature control system. Additionally or alternatively, the control unit is also configured to operate the cold source such that the temperature of the temperature-controlled fluid leaving the cold source precisely corresponds to the lowest setpoint temperature of the temperature control loop. This ingenious measure also enables significant energy savings in the temperature control system.
[0019] More preferably, the control unit of the temperature control system is configured to shut off the heat source when the temperature control fluid supplied to the heat source has a temperature greater than or equal to the highest setpoint temperature of one of the temperature control loops.
[0020] Preferably, the control unit is also configured to shut off the cold source when the temperature-controlled fluid supplied to the cold source has a temperature less than or equal to the minimum setpoint temperature of one of the temperature control loops. This measure also enables energy-saving operation of the temperature control system.
[0021] More preferably, the pump is a speed-controlled pump. In this way, different quantities of temperature-controlled fluid can be delivered at different operating times of the machine tool. Alternatively, an auxiliary pump can be connected in parallel with the main pump to meet different quantities of temperature-controlled fluid.
[0022] The temperature control system according to the invention is preferably integrated into the machine tool. However, the temperature control system may also be configured as a separate modular unit outside the machine tool housing, with only the wiring of the temperature control loop being introduced and led out of the machine tool. Attached Figure Description
[0023] Preferred exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings:
[0024] Figure 1This is a schematic diagram of a machine tool with a temperature control system according to a preferred exemplary embodiment of the present invention, and
[0025] Figure 2 It has different temperature control loops, only partially shown. Figure 1 A schematic cross-sectional view of the machine tool. Detailed Implementation
[0026] The following is for reference. Figure 1 and Figure 2 A detailed description of machine tool 1 with temperature control system 2 is provided.
[0027] Temperature control system 2 is configured for temperature control of various areas or components of the machine tool.
[0028] like Figure 2 As shown, these areas or components may be, for example, bed 100, Z-column 101, cover 102, drive housing 103 or drive, Z-axis with spindle 104 or work area 106.
[0029] Each area of machine tool 1 is temperature-controlled by a separate temperature control loop.
[0030] Temperature control system 2 includes tank 3 and pump 4 (see...) Figure 1 The auxiliary pump 44 can also be connected in parallel with the main pump 4.
[0031] Pump 4 and / or auxiliary pump 44 are configured to deliver a temperature-controlled fluid from tank 3. The temperature-controlled fluid may be water, oil, emulsion, or another liquid.
[0032] like Figure 1 Specifically shown, a temperature control loop is provided for each area to be subject to temperature control. The first temperature control loop 10 is provided for temperature control of the Z-pillar 101. The second temperature control loop 20 is provided for temperature control of the bed 100. The third temperature control loop 30 is provided for temperature control of the working area 106. The fourth temperature control loop 40 is provided for temperature control of the drive housing 103. The fifth temperature control loop 50 is provided for temperature control of the lubricating oil or cooling lubricant.
[0033] The temperature control system 2 also includes a heat source 6 and a cold source 7. Figure 1 As can be seen, tank 3 is connected to inlet 60 of heat source 6. Tank 3 is also connected to inlet 70 of cold source 7. Supply line 110 is split at branch 111, so that temperature-controlled fluid supplied by means of a pump can be supplied to both heat source 6 and cold source 7.
[0034] from Figure 1As can be seen, a mixing valve is provided in each temperature control loop. More specifically, the first mixing valve 11 is configured in the first temperature control loop 10, the second mixing valve 21 is configured in the second temperature control loop 20, the third mixing valve 31 is configured in the third temperature control loop 30, the fourth mixing valve 41 is configured in the fourth temperature control loop 40, and the fifth mixing valve 51 is configured in the fifth temperature control loop 50.
[0035] from Figure 1 It can be further seen that, starting from the outlet 61 of the heat source, the wiring for the temperature control loop is branched, such that the outlet 61 of the heat source 6 is connected to each mixing valve 11, 21, 31, 41, 51. In the same manner, the outlet 71 of the cold source 7 is also connected to each mixing valve 11, 21, 31, 41, 51 via multiple branches (see...). Figure 1 ).
[0036] Therefore, each mixing valve has a first inlet 81 connected to a heat source, a second inlet 82 connected to a cold source, and an outlet 83 connected to one of the temperature control loops 10, 20, 30, 40, 50.
[0037] The temperature control system 2 also includes a control unit 8, which in Figure 1 The diagram is schematically shown. Control unit 8 is configured to set a predetermined setpoint temperature for each of the temperature control loops 10, 20, 30, 40, and 50 via mixing valves 11, 21, 31, 41, and 51. In this configuration, corresponding to the desired setpoint temperature, the inflow from heat source 6 and / or cold source 7 increases, decreases, or is completely interrupted. The mixing valves can also be completely shut off, preventing the supply of heated or cooled temperature control fluid to the temperature control loop. For clarity, Figure 1 The connection between the control unit 8 and the corresponding mixing valve is not shown.
[0038] from Figure 1 It can be further seen that temperature sensor 9 is configured downstream of each mixing valve 11, 21, 31, 41, 51 in the corresponding temperature control loops 10, 20, 30, 40, 50. Temperature sensor 9 detects the temperature in the corresponding temperature control loop. Temperature sensor 9 is also connected to control unit 8, which therefore controls the mixing valve based on the temperature recorded in the corresponding temperature control loop. For clarity, the connection between temperature sensor 9 and control unit 8 is shown in the diagram. Figure 1 It was not drawn in the middle either.
[0039] from Figure 1 and Figure 2It can be further seen that the first temperature control loop 10 is configured to directly control the temperature of the temperature control loop. That is, the first temperature control loop 10 is directly introduced into the area of the machine tool to be temperature controlled, which is the Z-pillar 101 in this exemplary embodiment. Here, the heat exchanger 12 is directly integrated into the Z-pillar 101. As a result, no further heat transfer to other loops occurs.
[0040] The other temperature control loops 20, 30, 40, and 50 are configured such that a liquid-air heat exchanger is disposed in each of these temperature control loops. More specifically, the first liquid-air heat exchanger 22 is disposed in the second temperature control loop 20. The second liquid-air heat exchanger 32 is disposed in the third temperature control loop 30. The third liquid-air heat exchanger 42 is disposed in the fourth temperature control loop 40. The fourth liquid-air heat exchanger 52 is disposed in the fifth temperature control loop 50 (see...). Figure 2 ).
[0041] Four liquid-air heat exchangers 22, 32, 42, and 52 can now control the temperature of the area of machine tool 1 using air. This is in Figure 2 It is shown schematically in the middle.
[0042] In this configuration, the second liquid-air heat exchanger 32 is used to provide barrier air 107 in the region along the Z-axis, which has the main shaft 104. This is in Figure 2 The diagram is schematically shown. Air blocking can be used, for example, to deflect or redirect debris (e.g., oil mist) in the working area 106 of a machine tool.
[0043] Reference numeral 105 relates to a bellows that enables axial movement of the Z-axis having the spindle 104 and specifically protects the components configured in the drive housing 103 from contamination.
[0044] Advantageously, the control unit 8 is configured such that temperature control of the machine tool bed 100 or other areas via direct temperature control by heat conduction occurs only after temperature control in the machine tool area via liquid-air heat exchangers 22, 32, 42, 52 has already occurred. This is because, due to heat conduction, temperature regulation occurs significantly faster in the case of direct temperature control than in the case of temperature control via air (e.g., in the working area). Therefore, for energy reasons, it is useful to first supply temperature control fluid to the liquid-air heat exchangers and thus perform temperature control on the air temperature control area of the machine tool in order to prepare the machine tool for operation. Only at a later point in time can the area of the machine tool to be temperature controlled by direct temperature control be temperature controlled. Therefore, as Figure 1 As shown, for example, the first temperature control loop 10 can be completely shut off by means of an additional shut-off valve 108.
[0045] like Figure 1 As further shown, all temperature control loops 10, 20, 30, 40, and 50 are routed back to tank 3.
[0046] The number of temperature control loops is chosen for illustrative purposes only. At least two loops are allowed, but more than five loops as shown are also permitted.
[0047] Furthermore, the temperature control system 2 can be operated via the control unit 8 such that when the temperature of the temperature control fluid in tank 3 corresponds to the hottest desired setpoint temperature in one of the temperature control loops, the mixing valve is configured to allow only 100% of the temperature control fluid from the line branch equipped with heat source 6 to pass through for that temperature control loop. Heat source 6 can, of course, be shut off here because the temperature of the temperature control fluid precisely corresponds to the highest setpoint temperature without requiring additional heat input.
[0048] When the machine tool releases relatively more heat to the temperature control fluid, keeping the temperature control fluid in tank 3 at a relatively high temperature, the heat source 6 in the temperature control system 2 can be omitted. The temperature control fluid flows directly from branch 111 to the first inlet 81 of the mixing valves 11, 21, 31, 41 and 51.
[0049] Alternatively or additionally, heat source 6 may be configured in tank 3 to heat the temperature control fluid to a temperature corresponding to the hottest desired setpoint temperature in one of the temperature control loops, for example, before machining on a machine tool.
[0050] When the temperature of the temperature-controlled fluid supplied from tank 3 to cold source 7 corresponds to the coldest temperature in the temperature control system, this also applies to the cold branch of temperature control system 2. Therefore, cold source 7 can of course be shut off under this operating condition.
[0051] Explanation of reference numerals in the attached figures
[0052] 1 Machine tool
[0053] 2 Temperature Control System
[0054] 3 cans
[0055] 4 pumps
[0056] 6. Heat source
[0057] 7. Cold source
[0058] 8 Control Unit
[0059] 9. Temperature sensor
[0060] 10 First Temperature Control Loop
[0061] 11 First mixing valve
[0062] 12 Heat Exchangers
[0063] 20 Second temperature control loop
[0064] 21 Second mixing valve
[0065] 22 First Liquid-Air Heat Exchanger
[0066] 30 Third temperature control loop
[0067] 31 Third mixing valve
[0068] 32 Second Liquid-Air Heat Exchanger
[0069] 40 Fourth temperature control loop
[0070] 41 Fourth mixing valve
[0071] 42 Third Liquid-Air Heat Exchanger
[0072] 44 Auxiliary Pump
[0073] 50 Fifth temperature control loop
[0074] 51 Fifth mixing valve
[0075] 52 Fourth Liquid-Air Heat Exchanger
[0076] 60. Heat source inlet
[0077] 61. Heat source outlet
[0078] 70. Cold source inlet
[0079] 71. Cold source outlet
[0080] 81 First inlet of the mixing valve
[0081] 82 Second inlet of mixing valve
[0082] 83. Mixing valve outlet
[0083] 100 bed frame
[0084] 101 Z-pillar
[0085] 102 Cover / Shell
[0086] 103 Driver Housing
[0087] 104 Z-axis with a spindle
[0088] 105 Corrugated Pipe
[0089] Work Area 106
[0090] 107. Blocks air
[0091] 108 Stop Valve
[0092] 110 Supply Line
[0093] 111 branches
Claims
1. Machine tool with a temperature control system (2) which is configured for temperature control of regions of the machine tool, wherein the temperature control system (2) comprises: - a tank (3) which is filled with a temperature control fluid, - a pump (4) for delivering the temperature control fluid from the tank (3), - a temperature control circuit (10, 20, 30, 40, 50) for each region of the machine tool to be subjected to temperature control, wherein each temperature control circuit leads back to the tank (3), - a branch (111), wherein the branch (111) is connected to the pump (4), - a cold source (7), wherein the branch (111) is connected to an inlet (70) of the cold source (7), - wherein a mixing valve (11, 21, 31, 41, 51) is configured in each temperature control circuit (10, 20, 30, 40, 50), wherein each mixing valve has a first inlet (81) connected to the branch (111), a second inlet (82) connected to the cold source (7) and an outlet (83) leading to the temperature control circuit, and - a control unit (8) which is configured to set a predetermined setpoint temperature for each temperature control circuit by means of the mixing valves (11, 21, 31, 41, 51).
2. Machine tool according to claim 1, wherein a heat source (6) is configured between the branch (111) and the first inlet (81) of the mixing valve, which heat source is configured to heat the temperature control fluid supplied to the inlet (81) of the mixing valve.
3. Machine tool according to claim 1 or 2, wherein a heat source (6) is configured in the tank (3), which heat source is configured to heat the temperature control fluid in the tank (3).
4. Machine tool according to any of the preceding claims, wherein at least one temperature control circuit (10) directly temperature controls a region of the machine tool.
5. Machine tool according to any of the preceding claims, wherein at least one temperature control circuit (11, 21, 31, 41, 51) has a liquid-air heat exchanger (22, 32, 42, 52) in order to temperature control a region of the machine tool by means of air.
6. Machine tool according to claim 5, wherein the region of the machine tool to be temperature controlled by means of air is a work zone (106) of the machine tool.
7. Machine tool according to claim 5 or 6, wherein the temperature controlled air from the liquid-air heat exchanger is barrier air (107) at a region of the machine tool.
8. Machine tool according to any of the preceding claims, further comprising a plurality of temperature sensors (9), wherein the temperature sensors (9) are configured on the temperature control system (2) and / or at regions of the machine tool to be subjected to temperature control.
9. Machine tool according to any of the preceding claims, wherein the heat source (6) is a cartridge heater and / or wherein the cold source (7) is an internal cold source or an external cold source of the machine tool. 10. Machine tool according to any one of claims 5 to 9, wherein the liquid-air heat exchanger (22, 32, 42, 52) is an air temperature control unit or a recirculation unit.
11. Machine tool according to any one of claims 5 to 10, wherein the control unit (8) is configured to first temperature control the areas to be temperature controlled by means of the liquid-air heat exchanger (22, 32, 42, 52) and subsequently to temperature control the areas to be directly temperature controlled by means of a temperature control circuit.
12. Machine tool according to any one of the preceding claims, - wherein the control unit (8) is configured to operate the heat source (6) such that the temperature of the temperature control fluid leaving the heat source (6) exactly corresponds to the highest setpoint temperature of one of the temperature control circuits (10, 20, 30, 40, 50), and / or - wherein the control unit (8) is configured to operate the cold source such that the temperature of the temperature control fluid leaving the cold source (7) exactly corresponds to the lowest setpoint temperature of a temperature control circuit.
13. Machine tool according to any one of the preceding claims, wherein the control unit (8) is configured to switch off the heat source (6) when the temperature control fluid supplied from the tank (3) to the heat source (6) has a temperature greater than or equal to the maximum setpoint temperature of one of the temperature control circuits.
14. Machine tool according to any one of the preceding claims, wherein the control unit (8) is configured to switch off the cold source (7) when the temperature control fluid supplied from the tank (3) to the cold source (7) has a temperature less than or equal to the minimum setpoint temperature of one of the temperature control circuits.