Nitrogen balancing system and numerical control machine tool

Abstract

The application relates to the technical field of processing equipment, and discloses a nitrogen balancing system and a numerical control machine tool. The nitrogen balancing system is used for the numerical control machine tool and comprises a cylinder barrel part, a piston part and a plurality of regulating parts. The cylinder barrel part is arranged on a machine bed and is formed with a main cavity and a plurality of auxiliary cavities. The piston part comprises a piston body and a piston rod. The piston body is slidably arranged in the main cavity and divides the main cavity into a rod cavity and a rodless cavity. The piston rod is slidably arranged in the cylinder barrel and is connected between the piston body and a spindle box. At least part of the piston rod is arranged in the rod cavity. The regulating parts are arranged in one-to-one correspondence with the auxiliary cavities. Each regulating part is used for controlling one auxiliary cavity to be on or off the rodless cavity. A gas supply device is connected to the cylinder barrel part and is used for conveying nitrogen into the rodless cavity. A control device is signal-connected to the regulating parts. The volume of the rodless cavity is positively correlated with the position height of the spindle box. The control device is used for controlling the regulating parts to operate, so that the number of the auxiliary cavities on the rodless cavity is negatively correlated with the position height of the spindle box.

Description

Technical Field

[0001] This application relates to the field of processing equipment technology, and in particular to a nitrogen balance system and a CNC machine tool. Background Technology

[0002] Some CNC machine tools are equipped with nitrogen balancing systems to provide a balancing force to balance the weight of the spindle box. However, in practical applications, it has been found that the balancing force provided by the nitrogen balancing system tends to fluctuate significantly with the spindle box stroke, which is detrimental to ensuring the balancing effect of the nitrogen balancing system on the weight of the spindle box and limits the improvement of the machining accuracy of CNC machine tools. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art or related technologies.

[0004] In view of this, a nitrogen balancing system is provided according to a first aspect of the embodiments of this application for use in a CNC machine tool. The CNC machine tool includes a bed and a spindle box that is vertically and flexibly disposed on the bed. The nitrogen balancing system includes: The cylinder section is located on the bed and forms a main cavity and multiple auxiliary cavities; The piston section includes a piston body and a piston rod. The piston body is slidably disposed in the main cavity and divides the main cavity into a rod chamber and a rodless chamber. The piston rod is slidably disposed in the cylinder section and connected between the piston body and the main shaft box. At least a portion of the piston rod is located in the rod chamber. Multiple control units are arranged in a one-to-one correspondence with the sub-cavities. Each control unit is used to control the conduction or cutoff of a sub-cavity to the rodless cavity. A gas supply device, connected to the cylinder section and used to supply nitrogen gas into the rodless chamber; The control device has signals connected to multiple control units; The volume of the rodless cavity is positively correlated with the position and height of the spindle box; the control device is used to control the operation of multiple adjustment units so that the number of secondary cavities connected to the rodless cavity is negatively correlated with the position and height of the spindle box.

[0005] In one feasible implementation, the axial direction of the main cavity is consistent with the height direction of the cylinder section, the piston body is adapted to slide along the axial direction of the main cavity between a first axial position and a second axial position, and the rod chamber is located between the top end of the cylinder section and the rodless chamber. When the spindle box is in its highest working position, the piston body is in the first axial position, and the volume of the rodless chamber is the first volume; when the spindle box is in its lowest working position, the piston body is in the second axial position, and the volume of the rodless chamber is the second volume. Among them, the volumes of multiple secondary cavities are the same, and the sum of the volumes of multiple secondary cavities is equal to the difference between the first volume and the second volume.

[0006] In one feasible implementation, the control device includes: The acquisition module is used to obtain the real-time position and height of the spindle box; The processing module is used to determine the real-time axial position and actual sliding direction of the piston body in the main cavity based on the real-time position and height of the spindle box. The first control module is used to control multiple adjustment parts to be in a closed state when the piston body is in the first axial position, so that multiple secondary chambers are cut off to the rodless chamber. The second control module is used to control multiple adjustment parts to be in the open state when the piston body is in the second axial position, so that multiple secondary chambers are connected to the rodless chamber. The third control module is used to control an adjustment unit to switch to the open state every time the piston body slides a preset distance along the first direction, so that the corresponding secondary chamber is connected to the rodless chamber. The fourth control module is used to control a regulating unit to switch to the closed state every time the piston body slides a preset distance along the second direction, so that the corresponding secondary chamber is cut off from the rodless chamber; Wherein, the first direction is the direction from the first axial position to the second axial position, and the second direction is opposite to the first direction; the preset distance is one-Nth of the distance between the first axial position and the second axial position, where N is the number of secondary cavities.

[0007] In one feasible implementation, the nitrogen balance system further includes: Multiple pressure relief sections are installed in the cylinder section and connected to the control device. Each pressure relief section is arranged in a one-to-one correspondence with a secondary cavity. Each pressure relief section is used to control the conduction or cut-off of a secondary cavity to the external environment. The control device also includes: The fifth control module is used to control the opening of the pressure relief section corresponding to the secondary cavity when the secondary cavity is cut off from the rodless cavity, so as to connect the secondary cavity to the external environment until the pressure of the secondary cavity is consistent with the external environment air pressure.

[0008] In one feasible implementation, the nitrogen balance system further includes: A pressure detection device is installed in the cylinder section and its signal is connected to the control device. The pressure detection device is used to obtain the actual pressure of the rodless chamber. The control device signal is connected to the gas supply device, and the control device also includes: The sixth control module is used to control the gas supply device to deliver nitrogen into the rodless chamber when the actual pressure is less than or equal to the preset pressure.

[0009] In one feasible implementation, the cylinder section includes: The cylinder is set on the bed and forms a main cavity and multiple secondary cavities. The two ends of the main cavity have a first cavity opening and a second cavity opening, and the two ends of the secondary cavities have a third cavity opening and a fourth cavity opening, respectively. The first cavity opening and the third cavity opening are located at the top of the cylinder, and the second cavity opening and the fourth cavity opening are located at the bottom of the cylinder. The first end cap is detachably disposed at the top of the cylinder. When disposed at the top of the cylinder, the first end cap covers the first cavity opening and the third cavity opening. The second end cap is detachably disposed at the bottom end of the cylinder. When disposed at the bottom end of the cylinder, the second end cap covers the second cavity opening and the fourth cavity opening. The piston rod slides through the first end cap.

[0010] In one feasible embodiment, the cylinder section further includes: A first sealing element is disposed on the first end cap. When the first end cap is disposed at the top of the cylinder, the first sealing element is located between the top of the cylinder and the first end cap. The second sealing element is disposed on the second end cap. When the second end cap is disposed at the bottom end of the cylinder, the second sealing element is located between the bottom end of the cylinder and the second end cap. The main pressure relief valve is located on the second end cover. The main pressure relief valve is used to control the opening or closing of the rodless chamber to the external environment.

[0011] In one feasible implementation, the control unit includes: A connecting tube, one end of which is connected to the rodless cavity and the other end of which is connected to the auxiliary cavity; The first shut-off valve is installed on the connecting pipe and its signal is connected to the control device. The first shut-off valve is used to open or close the connecting pipe.

[0012] In one feasible implementation, the gas supply device includes: Gas source department; The gas delivery pipe has one end connected to the nitrogen output end of the gas source section and the other end connected to the rodless chamber. The second shut-off valve is installed in the gas pipeline and is used to open or close the gas pipeline.

[0013] A second aspect of the embodiments of this application provides a CNC machine tool, comprising: Bed frame; The spindle box is height-adjustable and mounted on the bed; Nitrogen balance system as proposed in any of the first aspects above.

[0014] Compared with the prior art, this application has at least the following beneficial effects: The nitrogen balancing system provided in this application can, in practical applications, increase the number of secondary chambers connected to the rodless chamber as the height of the spindle box decreases, thereby compensating for the volumetric compression of the rodless chamber and preventing a significant increase in gas pressure due to volumetric compression. Conversely, as the height of the spindle box increases, the number of secondary chambers connected to the rodless chamber decreases, thereby limiting the gas volume on the side of the piston body facing the rodless chamber and preventing a significant drop in gas pressure due to volumetric expansion. This improves the stability of the balancing force applied by the nitrogen balancing system to the spindle box, reduces fluctuations in the balancing force during the spindle box's lifting and lowering process, and enhances the gravity balance performance of the vertical axis of the CNC machine tool, providing favorable conditions for high-speed and high-precision machining.

[0015] The above description is merely an overview of the technical solution provided in this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other features and effects of this application more obvious and easy to understand, the following are specific examples of the implementation methods of this application. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of exemplary embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic structural diagram of a nitrogen balance system according to an embodiment of this application, viewed from a first perspective; Figure 2 A schematic structural diagram of a nitrogen balance system according to an embodiment of this application, viewed from a second perspective; Figure 3 A schematic structural diagram of a nitrogen balance system according to an embodiment of this application, viewed from a third perspective; Figure 4 A schematic structural diagram of a nitrogen balance system provided in this application from a fourth perspective; Figure 5 A schematic structural diagram of a CNC machine tool according to an embodiment of this application.

[0017] in, Figures 1 to 5 The correspondence between the reference numerals and component names in the attached drawings is as follows: 100. Nitrogen balance system; 110. Cylinder section; 111. Cylinder body; 112. First end cap; 113. Second end cap; 114. Main pressure relief valve; 120. Piston section; 121. Piston body; 122. Piston rod; 130. Control section; 131. Connecting pipe; 132. First shut-off valve; 140. Gas supply device; 141. Gas source section; 142. Gas delivery pipe; 143. Second shut-off valve; 150. Control device; 160. Pressure relief section; 161. Pressure relief pipe; 162. Secondary pressure relief valve; 170. Pressure detection device; 200. Bed; 210. Base; 220. Post; 230. Beam; 300. Spindle box; 1101, Main cavity; 1101a, Rod cavity; 1101b, Rodless cavity; 1102, Secondary cavity. Detailed Implementation

[0018] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0019] like Figures 1 to 5 As shown, a nitrogen balance system 100 is provided according to a first aspect of the present application for use in a CNC machine tool. The CNC machine tool includes a bed 200 and a spindle box 300 that is vertically and flexibly disposed on the bed 200. The nitrogen balance system 100 includes: a cylinder section 110 disposed on the bed 200 and forming a main cavity 1101 and a plurality of secondary cavities 1102; a piston section 120 including a piston body 121 and a piston rod 122. The piston body 121 is slidably disposed in the main cavity 1101 and divides the main cavity 1101 into a rod cavity 1101a and a rodless cavity 1101b. The piston rod 122 slidably passes through the cylinder section 110 and connects the piston body 121 and the spindle box 300, at least part of which... The piston rod 122 is located in the rod chamber 1101a; multiple control units 130 are arranged one-to-one with the auxiliary chambers 1102, and each control unit 130 is used to control one auxiliary chamber 1102 to be open or closed to the rodless chamber 1101b; a gas supply device 140 is connected to the cylinder section 110 and is used to supply nitrogen to the rodless chamber 1101b; a control device 150 is connected to the multiple control units 130; wherein, the volume of the rodless chamber 1101b is positively correlated with the position height of the spindle box 300; the control device 150 is used to control the operation of the multiple control units 130 so that the number of auxiliary chambers 1102 connected to the rodless chamber 1101b is negatively correlated with the position height of the spindle box 300.

[0020] The nitrogen balance system 100 proposed in this application can be used as a system in a CNC machine tool or installed in a CNC machine tool in practical applications. The nitrogen balance system 100 includes the aforementioned cylinder section 110, piston section 120, gas supply device 140, control device 150, and multiple adjustment sections 130. The cylinder section 110 forms a main cavity 1101. The piston body 121 of the piston section 120 is slidably disposed within the main cavity 1101 and can divide the main cavity 1101 into a rod cavity 1101a and a rodless cavity 1101b. At least a portion of the piston rod 122 of the piston section 120 is located within the rod cavity 1101a. The piston body 121 is connected to the spindle box 300 of the CNC machine tool via the piston rod 122. The gas supply device 140 is used to supply nitrogen to the rodless cavity 1101b to achieve a certain pressure within the rodless cavity 1101b, and the volume of the rodless cavity 1101b is... The position of the spindle box 300 is positively correlated with its height. That is, as the position of the spindle box 300 rises, the volume of the rodless chamber 1101b increases synchronously, and as the position of the spindle box 300 falls, the volume of the rodless chamber 1101b decreases synchronously. Thus, the pressure of the nitrogen gas in the rodless chamber 1101b acting on the piston body 121 can be further applied to the spindle box 300 through the piston rod 122 to balance the gravity of the spindle box 300. In this way, the nitrogen balance system 100 can provide a balancing force to the spindle box 300 and improve the stability of the spindle box 300 during operation.The cylinder section 110 also forms a plurality of secondary chambers 1102, and each secondary chamber 1102 corresponds one-to-one with a control unit 130. A control device 150 controls the operation of the plurality of control units 130 so that the number of secondary chambers 1102 connected to the rodless chamber 1101b is negatively correlated with the position height of the spindle box 300. That is, the control device 150 can control the operation of the plurality of control units 130 according to the position height of the spindle box 300, so that as the spindle box 300 descends, the number of secondary chambers 1102 connected to the rodless chamber 1101b increases, and as the spindle box 300 rises, the number of secondary chambers 1102 connected to the rodless chamber 1101b decreases. Based on this, as the position height of the spindle box 300 decreases, the number of secondary chambers 1102 connected to the rodless chamber 1101b can increase accordingly, thereby balancing the nitrogen gas system. The nitrogen balance system 100 can utilize the volume of the secondary cavity 1102 connected to the rodless cavity 1101b to compensate for the volume compression of the rodless cavity 1101b, thus preventing a significant increase in gas pressure within the rodless cavity 1101b due to volume compression. Furthermore, as the position height of the spindle box 300 increases, the number of secondary cavities 1102 connected to the rodless cavity 1101b can be reduced accordingly. As a result, the nitrogen balance system 100 can limit the gas volume and quantity on the side of the piston body 121 facing the rodless cavity 1101b, preventing a significant decrease in gas pressure within the rodless cavity 1101b due to volume expansion. This, in turn, helps improve the stability of the balancing force applied by the nitrogen balance system 100 to the spindle box 300, weakens the fluctuation of the balancing force during the lifting and lowering of the spindle box 300, and improves the gravity balance performance of the vertical axis of the CNC machine tool, providing favorable conditions for high-speed and high-precision machining of the CNC machine tool.

[0021] It is understood that the aforementioned rodless chamber 1101b and the aforementioned rod chamber 1101a are not connected to each other. In practical applications, the rod chamber 1101a can be connected to the external environment in order to reduce the pressure fluctuation of the rod chamber 1101a during the movement of the piston section 120, and further improve the stability of the balancing force output by the nitrogen balance system 100. The rodless chamber 1101b is not connected to the external environment, or the connection and disconnection state between the rodless chamber 1101b and the external environment is controllable. When the nitrogen balance system 100 needs to provide balancing force to the spindle box 300, the rodless chamber 1101b can be set to be disconnected from the external environment, thereby ensuring the pressure stability in the rodless chamber 1101b.

[0022] It is understandable that, in practical applications, the piston rod 122 and the spindle box 300 can be directly or indirectly connected, and no further restrictions are imposed here.

[0023] Understandably, in practical applications, the sliding direction of the piston body 121 can be set to be consistent with the lifting direction of the spindle box 300, and the piston rod 122 can be located above the piston body 121, so that the pressure in the rodless chamber 1101b can act on the spindle box 300 through the piston part 120 to provide a balancing force for the spindle box 300.

[0024] It is understandable that the operating status of multiple control units 130 can be controlled independently; the specific type of control device 150 can be set according to actual needs, for example, it can be, but is not limited to, a programmable logic controller, a microcontroller, an industrial computer, etc.; in practical applications, control logic settings or program editing can be performed on the control device 150 so that the control device 150 can control the operation of multiple control units 130, and the number of secondary cavities 1102 connected to the rodless cavity 1101b is negatively correlated with the position height of the spindle box 300, without further limitations.

[0025] It is understood that the control device 150 can acquire the position and height of the spindle head 300 in various ways. For example, the control device 150 can be signal-connected to the CNC system of the CNC machine tool to acquire the aforementioned position and height through the CNC system; or, the control device 150 can include a position detection device for monitoring the position of the spindle head 300 to acquire the aforementioned position and height through the position detection device. The specific method by which the control device 150 acquires the position and height of the spindle head 300 can be selected according to actual needs and is not limited to the above examples. Here, we will not list all the feasible methods by which the control device 150 acquires the position and height of the spindle head 300.

[0026] It is understood that before using the nitrogen balance system 100 provided in this application to provide balancing force to the spindle box 300, the airtightness of the rodless cavity 1101b and multiple secondary cavities 1102 can be checked in advance, and the overall control responsiveness of the nitrogen balance system 100 can be checked to ensure the reliability and stability of the nitrogen balance system 100 in practical applications.

[0027] It is understood that the spindle box 300 has a highest working position and a lowest working position in the lifting direction. Correspondingly, during the operation of the CNC machine tool, the volume of the rodless cavity 1101b is the largest when the spindle box 300 is in the aforementioned highest working position, and the smallest when the spindle box 300 is in the aforementioned lowest working position. In practical applications, the gas supply device 140 can input nitrogen into the rodless cavity 1101b when the spindle box 300 is in the aforementioned highest working position and multiple secondary cavities 1102 are all cut off from the rodless cavity 1101b, until the pressure in the rodless cavity 1101b reaches the target pressure, so as to ensure the balancing effect of the nitrogen balance system 100 on the spindle box 300. The aforementioned target pressure can be determined based on the following formula (1): p = G / (A2 - A1) In formula (1), p is the target pressure; G is the gravity of the spindle box 300; A1 is the effective area of ​​the piston body 121 on the side of the rod chamber 1101a; A2 is the effective area of ​​the piston body 121 on the side of the rodless chamber 1101b.

[0028] In one feasible implementation, the axial direction of the main cavity 1101 is aligned with the height direction of the cylinder portion 110. The piston body 121 is adapted to slide along the axial direction of the main cavity 1101 between a first axial position and a second axial position. The rod cavity 1101a is located between the top end of the cylinder portion 110 and the rodless cavity 1101b. When the spindle box 300 is in the highest working position, the piston body 121 is in the first axial position, and the volume of the rodless cavity 1101b is the first volume. When the spindle box 300 is in the lowest working position, the piston body 121 is in the second axial position, and the volume of the rodless cavity 1101b is the second volume. The volumes of the multiple secondary cavities 1102 are the same, and the sum of the volumes of the multiple secondary cavities 1102 is equal to the difference between the first volume and the second volume.

[0029] In this technical solution, the axial direction of the main cavity 1101 can be aligned with the height direction of the cylinder portion 110, and the rod cavity 1101a is located above the rodless cavity 1101b. Thus, the sliding direction of the piston body 121 is aligned with the lifting direction of the spindle box 300, and the piston rod 122 is located above the piston body 121, which facilitates the pressure in the rodless cavity 1101b to act on the spindle box 300 through the piston portion 120, thereby providing a balancing force to the spindle box 300. The piston body 121 slides between a first axial position and a second axial position of the main cavity 1101, and the first axial position and the second axial position are respectively matched with the highest working position and the lowest working position of the spindle box 300.

[0030] The sum of the volumes of the multiple secondary chambers 1102 can be equal to the difference between the first and second volumes. Based on this, the sum of the volumes of the multiple secondary chambers 1102 is consistent with the volume change range of the rodless chamber 1101b. Thus, on the one hand, when the volume of the rodless chamber 1101b is compressed from the first volume to the second volume, the multiple secondary chambers 1102 can be controlled to be connected to the rodless chamber 1101b to compensate for the volume compression of the rodless chamber 1101b and reduce the pressure increase range within the rodless chamber 1101b. On the other hand, when the volume of the rodless chamber 1101b expands from the second volume to the first volume, the multiple secondary chambers 1102 can be controlled to be cut off from the rodless chamber 1101b to avoid excessive gas volume and gas quantity on the side of the piston body 121 corresponding to the rodless chamber 1101b, which helps to reduce the pressure drop phenomenon in the rodless chamber 1101b caused by volume expansion.

[0031] The volumes of the multiple secondary chambers 1102 can be consistent, which facilitates the control of the multiple secondary chambers 1102 to be turned on or off one by one into the rodless chamber 1101b during the descent or ascent of the main spindle box 300. This allows the gas volume on the side of the piston body 121 corresponding to the rodless chamber 1101b to be gradually restored to the aforementioned first volume. This helps to avoid excessive compression or expansion of the gas on the side of the piston body 121 corresponding to the rodless chamber 1101b, and can further improve the stability of the balance force.

[0032] In one feasible implementation, the control device 150 includes: a data acquisition module for acquiring the real-time position and height of the spindle box 300; a processing module for determining the real-time axial position and actual sliding direction of the piston body 121 within the main cavity 1101 based on the real-time position and height of the spindle box 300; a first control module for controlling multiple control units 130 to be in a closed state when the piston body 121 is in a first axial position, so that multiple secondary cavities 1102 are all cut off to the rodless cavity 1101b; and a second control module for controlling multiple control units 130 to be in an open state when the piston body 121 is in a second axial position, so that multiple secondary cavities 1102 are all connected to the rodless cavity 1101b. 101b; A third control module is used to control an adjustment unit 130 to switch to the open state when the piston body 121 slides a preset distance along the first direction, so that the corresponding secondary cavity 1102 is connected to the rodless cavity 1101b; A fourth control module is used to control an adjustment unit 130 to switch to the closed state when the piston body 121 slides a preset distance along the second direction, so that the corresponding secondary cavity 1102 is cut off from the rodless cavity 1101b; wherein, the first direction is the direction from the first axial position to the second axial position, and the second direction is opposite to the first direction; the preset distance is one-Nth of the distance between the first axial position and the second axial position, and N is the number of secondary cavities 1102.

[0033] In this technical solution, the control device 150 may include the aforementioned acquisition module, processing module, first control module, second control module, third control module and fourth control module. Based on the aforementioned configuration, when the spindle box 300 is in its highest or lowest working position, the multiple secondary chambers 1102 can be correspondingly cut off or connected to the rodless chamber 1101b. As a result, the gas volume on the side of the piston body 121 corresponding to the rodless chamber 1101b can be approximately equal to the aforementioned first volume. Furthermore, when the piston body 121 slides along the axial direction of the main chamber 1101 by the aforementioned preset distance, the control device 150 can control one secondary chamber 1102 to be correspondingly connected or cut off to the rodless chamber 1101b to compensate for the volume change of the rodless chamber 1101b. During the lifting and lowering process of the spindle box 300, the gas volume on the side of the piston body 121 corresponding to the rodless chamber 1101b can be gradually restored to the aforementioned first volume. This helps to avoid excessive compression or expansion of the gas on the side of the piston body 121 corresponding to the rodless chamber 1101b, and can further improve the stability of the balance force.

[0034] It is understood that the acquisition module can be connected to the CNC system of the CNC machine tool to obtain the aforementioned actual position height through the CNC system; or, the acquisition module may include a position sensor, which is used to detect the position height information of the spindle box 300.

[0035] It is understandable that the aforementioned actual sliding direction can be determined by combining the aforementioned actual position height change over time. For example, if the actual position height gradually increases over time, it indicates that the spindle box 300 is in the upward stroke, and correspondingly, the movement direction of the piston body 121 is the aforementioned second direction; conversely, if the actual position height gradually decreases over time, it indicates that the spindle box 300 is in the downward stroke, and correspondingly, the movement direction of the piston body 121 is the aforementioned first direction.

[0036] It is understandable that, in practical applications, the actual position height of the spindle box 300 and the actual axial position of the piston body 121 can be pre-calibrated, so as to facilitate the determination of the actual axial position based on the aforementioned actual position height.

[0037] Taking a case where there are six secondary chambers 1102 and six control units 130, when the spindle box 300 is in the aforementioned highest working position, the piston body 121 is in the aforementioned first axial position, and all the secondary chambers 1102 are cut off from the rodless chamber 1101b. When the spindle box 300 descends at a constant speed from the aforementioned highest working position, the piston body 121 will slide accordingly along the aforementioned first direction. When the sliding displacement of the piston body 121 reaches 1 times the aforementioned preset distance, the control device 150 controls one secondary chamber 1102 to be connected to the rodless chamber 1101b. At this time, the gas volume of the piston body 121 on the side of the rodless chamber 1101b is approximately equal to the sum of the current volume of the rodless chamber 1101b and the volume of one secondary chamber 1102, which is approximately equal to the aforementioned first volume, thereby maintaining the relative stability of the nitrogen pressure in the rodless chamber 1101b. As the piston body 121 continues to slide along the first direction, when its displacement reaches 2 times, 3 times, 4 times, 5 times and 6 times the preset distance in sequence, the control device 150 can increase the number of secondary chambers 1102 connected to the rodless chamber 1101b one by one by controlling the adjustment unit 130, until the main shaft box 300 drops to the lowest working position and all secondary chambers 1102 are connected to the rodless chamber 1101b, thereby realizing staged volume compensation, so that the gas volume on the side of the piston body 121 corresponding to the rodless chamber 1101b is gradually restored to the aforementioned first volume. When the spindle box 300 rises at a constant speed from the aforementioned lowest working position, when its displacement reaches 1, 2, 3, 4, 5, and 6 times the preset distance in sequence, the control device 150 can control the adjustment unit 130 to gradually reduce the number of secondary cavities 1102 connected to the rodless cavity 1101b, until the spindle box 300 rises to the highest working position and all secondary cavities 1102 are cut off from the rodless cavity 1101b.

[0038] like Figures 1 to 3 As shown, in one feasible embodiment, the nitrogen balance system 100 further includes: a plurality of pressure relief sections 160 disposed in the cylinder section 110 and signal-connected to the control device 150, wherein the pressure relief sections 160 are arranged in a one-to-one correspondence with the secondary chambers 1102, and each pressure relief section 160 is used to control a secondary chamber 1102 to be connected to or cut off from the external environment; the control device 150 further includes: a fifth control module, used to control the pressure relief section 160 corresponding to the secondary chamber 1102 to open when the secondary chamber 1102 is cut off from the rodless chamber 1101b, so that the secondary chamber 1102 is connected to the external environment until the pressure of the secondary chamber 1102 is consistent with the external environment pressure.

[0039] In this technical solution, the nitrogen balance system 100 may further include multiple pressure relief sections 160, and the control device 150 may further include the aforementioned fifth control module. Based on the aforementioned configuration, the pressure in the secondary chamber 1102 can be released through the pressure relief section 160. Correspondingly, when the secondary chamber 1102 is cut off from the rodless chamber 1101b, the control device 150 can control the pressure relief section 160 to release the corresponding pressure in the secondary chamber 1102, so as to avoid the accumulation and increase of gas pressure in the secondary chamber 1102. This is beneficial to ensuring the pressure balance effect of the secondary chamber 1102 on the rodless chamber 1101b when the secondary chamber 1102 is connected to the main chamber 1101, and further improving the stability of the balancing force provided by the nitrogen balance system 100.

[0040] Understandably, when the pressure in the secondary chamber 1102 is consistent with the external ambient air pressure, the fifth control module can control the corresponding pressure relief section 160 to close, so that the secondary chamber 1102 is cut off from the external environment, thereby preventing the pressure relief of the rodless chamber 1101b when the secondary chamber 1102 is connected to the rodless chamber 1101b.

[0041] For example, the pressure relief section 160 may include a pressure relief pipe 161 and a secondary pressure relief valve 162 disposed on the pressure relief pipe 161. One end of the pressure relief pipe 161 is connected to the secondary cavity 1102, and the other end is connected to the external environment. The aforementioned secondary pressure relief valve 162 may be an electric valve or a solenoid valve. The secondary pressure relief valve 162 may be signal-connected to the control device 150 to open and close under the control of the control device 150.

[0042] like Figure 2 As shown, in one feasible embodiment, the nitrogen balance system 100 further includes: a pressure detection device 170, disposed in the cylinder section 110 and signal-connected to the control device 150, the pressure detection device 170 being used to obtain the actual pressure of the rodless chamber 1101b; the control device 150 being signal-connected to the gas supply device 140, the control device 150 further including: a sixth control module, used to control the gas supply device 140 to supply nitrogen to the rodless chamber 1101b when the actual pressure is less than or equal to the preset pressure.

[0043] In this technical solution, the nitrogen balance system 100 may further include the aforementioned pressure detection device 170, and the control device 150 may further include the aforementioned sixth control module. Based on the aforementioned configuration, the nitrogen balance system 100 can detect the actual pressure of the rodless chamber 1101b through the pressure detection device 170, and when the actual pressure is less than or equal to the preset pressure, the control device 150 can control the gas supply device 140 to replenish nitrogen in the rodless chamber 1101b, so that the pressure in the rodless chamber 1101b is restored to above the preset pressure. This avoids the phenomenon of insufficient balance force caused by the gas pressure in the rodless chamber 1101b being too low, which is beneficial to further ensure the stability of the balance force. In practical applications, it can reduce the manual workload of replenishing gas in the rodless chamber 1101b, and improve the ease of use and automation level of the nitrogen balance system 100.

[0044] Understandably, as the nitrogen balance system 100 is used for an extended period, nitrogen in the rodless chamber 1101b is prone to leakage due to micro-leakage. Therefore, in practical applications, operators often need to periodically turn on the gas supply device 140 to replenish nitrogen in the rodless chamber 1101b. Based on the aforementioned configuration of this technical solution, the nitrogen balance system 100 can automatically detect the pressure in the rodless chamber 1101b through the pressure detection device 170, and automatically activate the gas supply device 140 to replenish nitrogen when the pressure in the rodless chamber 1101b falls below a certain level, which can reduce the workload and intensity of the operators. For example, the sixth control module is used to control the gas supply device 140 to deliver nitrogen into the rodless chamber 1101b when the actual pressure is less than or equal to the first preset pressure and the piston body 121 is stationary in the aforementioned first axial position, until the actual pressure reaches the aforementioned target pressure; the first preset pressure is less than the aforementioned target pressure and greater than or equal to 0.85 times the aforementioned target pressure.

[0045] It is understandable that during the volume expansion of the rodless chamber 1101b, the gas pressure inside the rodless chamber 1101b may sometimes decrease. Based on the aforementioned configuration of this technical solution, the nitrogen balance system 100 can also maintain the pressure inside the rodless chamber 1101b at a high level during the rising of the spindle box 300, thereby avoiding insufficient balance force. For example, the sixth control module is used to control the gas supply device 140 to supply nitrogen to the rodless chamber 1101b when the actual pressure is less than or equal to the second preset pressure and the piston body 121 slides along the aforementioned second direction, until the actual pressure reaches the aforementioned target pressure; the second preset pressure is equal to the aforementioned target pressure.

[0046] like Figures 2 to 4As shown, in one feasible embodiment, the cylinder section 110 includes: a cylinder 111 disposed on the bed 200 and having a main cavity 1101 and a plurality of auxiliary cavities 1102, the main cavity 1101 having a first cavity opening and a second cavity opening at both ends, and the auxiliary cavities 1102 having a third cavity opening and a fourth cavity opening at both ends, the first cavity opening and the third cavity opening being located at the top end of the cylinder 111, and the second cavity opening and the fourth cavity opening being located at the bottom end of the cylinder 111; a first end cap 112 detachably disposed on the top end of the cylinder 111, the first end cap 112 covering the first cavity opening and the third cavity opening when disposed on the top end of the cylinder 111; a second end cap 113 detachably disposed on the bottom end of the cylinder 111, the second end cap 113 covering the second cavity opening and the fourth cavity opening when disposed on the bottom end of the cylinder 111; wherein, the piston rod 122 slidably passes through the first end cap 112.

[0047] In this technical solution, the cylinder section 110 may include the aforementioned cylinder body 111, a first end cover 112, and a second end cover 113. Based on the aforementioned configuration, in practical applications, the cylinder section 110 can easily open the main cavity 1101 and the auxiliary cavity 1102 by disassembling at least one of the aforementioned first end cover 112 and the second end cover 113, thereby improving the convenience of maintenance and cleaning of the piston section 120, the main cavity 1101, and the auxiliary cavity 1102; the piston rod 122 slides through the first end cover 112, thereby being in a relatively high position to facilitate connection to the spindle box 300 in practical applications.

[0048] like Figure 2 and Figure 4 As shown, in one feasible embodiment, the cylinder section 110 further includes: a first seal disposed on the first end cap 112, wherein when the first end cap 112 is disposed on the top end of the cylinder body 111, the first seal is located between the top end of the cylinder body 111 and the first end cap 112; a second seal disposed on the second end cap 113, wherein when the second end cap 113 is disposed on the bottom end of the cylinder body 111, the second seal is located between the bottom end of the cylinder body 111 and the second end cap 113; and a main pressure relief valve 114 disposed on the second end cap 113, the main pressure relief valve 114 being used to control the rodless chamber 1101b to be open or closed to the external environment.

[0049] In this technical solution, the cylinder section 110 may further include the aforementioned first seal, second seal, and main pressure relief valve 114. Based on the aforementioned configuration, the cylinder section 110 can use the first seal to seal the gap between the first end cap 112 and the top end of the cylinder body 111, and can use the second seal to seal the gap between the second end cap 113 and the bottom end of the cylinder body 111, thereby ensuring the airtightness of the rodless chamber 1101b and the secondary chamber 1102, which is beneficial to ensuring the stability of the balancing force provided by the nitrogen balance system 100; the cylinder section 110 can also use the main pressure relief valve 114 to release the pressure in the rodless chamber 1101b, thereby avoiding excessive pressure in the rodless chamber 1101b and reducing the risk of cylinder explosion in the cylinder section 110.

[0050] In some feasible examples, the main pressure relief valve 114 is signal-connected to the control device 150; the acquisition module is also used to acquire acceleration information of the spindle box 300 when the spindle box 300 accelerates; the control device 150 also includes: The calculation module is used to calculate the matching pressure of the rodless cavity 1101b based on the acceleration information and the mass of the spindle box 300; The seventh control module is used to control the main pressure relief valve 114 to open when the actual pressure of the rodless chamber 1101b is higher than the aforementioned matching pressure, until the actual pressure of the rodless chamber 1101b is reduced to the aforementioned matching pressure. The eighth control module is used to control the gas supply device 140 to supply gas to the rodless cavity 1101b when the actual pressure of the rodless cavity 1101b is lower than the aforementioned matching pressure, until the actual pressure of the rodless cavity 1101b is raised to the aforementioned matching pressure. Among them, when the spindle box accelerates upward at 300°, the matching pressure can be determined based on the following formula (2): p1 = (G + ma) / (A2 - A1) When the spindle box accelerates downwards at 300°, the matching pressure can be determined based on the following formula (3): p1 = (G - ma) / (A2 - A1) In formulas (2) and (3), p1 is the matching pressure; G is the gravity of the spindle box 300; m is the mass of the spindle box 300; a is the acceleration of the spindle box 300; A1 is the effective area of ​​the piston body 121 corresponding to the rod chamber 1101a side; A2 is the effective area of ​​the piston body 121 corresponding to the rodless chamber 1101b side.

[0051] Based on this, the balancing force provided by the nitrogen balance system 100 can be matched to the actual motion state of the spindle box 300, which is beneficial to ensure the vertical axis gravity balance performance of the CNC machine tool during the acceleration of the spindle box 300.

[0052] In some feasible examples, the control device 150 also includes: The ninth control module is used to control the main pressure relief valve 114 to open when the actual pressure of the rodless chamber 1101b is greater than or equal to a preset pressure threshold until the actual pressure of the rodless chamber 1101b is lower than the preset pressure threshold; wherein the preset pressure threshold is greater than or equal to the aforementioned target pressure and less than or equal to 1.1 times the aforementioned target pressure.

[0053] Based on this, excessive pressure in the rodless chamber 1101b can be avoided, which can reduce the risk of cylinder explosion in the cylinder barrel 110.

[0054] like Figure 2 and Figure 4 As shown, in one feasible embodiment, the control unit 130 includes: a connecting pipe 131, one end of which is connected to the rodless cavity 1101b and the other end of which is connected to the auxiliary cavity 1102; and a first shut-off valve 132, which is disposed on the connecting pipe 131 and signal-connected to the control device 150, and the first shut-off valve 132 is used to open or close the connecting pipe 131.

[0055] In this technical solution, the control unit 130 may include the aforementioned connecting pipe 131 and the first shut-off valve 132. Based on the aforementioned configuration, when the secondary cavity 1102 corresponding to the control unit 130 needs to be connected to the rodless cavity 1101b, the first shut-off valve 132 of the control unit 130 can be controlled to open; conversely, when the secondary cavity 1102 corresponding to the control unit 130 needs to be shut off from the rodless cavity 1101b, the first shut-off valve 132 of the control unit 130 can be controlled to close. Thus, while ensuring the convenience of on / off control between the secondary cavity 1102 and the rodless cavity 1101b, the structural complexity of the control unit 130 can be reduced, which is beneficial to saving the usage cost and manufacturing difficulty of the control unit 130.

[0056] For example, the aforementioned first shut-off valve 132 can be an electric valve or a solenoid valve.

[0057] For example, the control unit 130 may also include a manifold, through which a plurality of connecting pipes 131 are connected to the rodless cavity 1101b.

[0058] In one feasible embodiment, the gas supply device 140 includes: a gas source 141; a gas delivery pipe 142, one end of which is connected to the nitrogen output end of the gas source 141, and the other end of which is connected to the rodless chamber 1101b; and a second shut-off valve 143 disposed on the gas delivery pipe 142, which is used to open or close the gas delivery pipe 142.

[0059] In this technical solution, the gas supply device 140 may include the aforementioned gas source unit 141, gas delivery pipe 142, and second shut-off valve 143. Based on the aforementioned configuration, the gas supply device 140 can store nitrogen in the gas source unit 141, and the start and stop control of the gas supply to the rodless chamber 1101b can be achieved by controlling the opening and closing of the second shut-off valve 143. This ensures the convenience of gas supply while reducing the structural complexity of the gas supply device 140, which helps to save on the operating cost and manufacturing difficulty of the gas supply device 140.

[0060] For example, the aforementioned gas source unit 141 may include a high-pressure nitrogen source, and the nitrogen output pressure of the aforementioned high-pressure nitrogen source can be set according to actual needs, without further limitations here.

[0061] For example, the aforementioned second shut-off valve 143 can be an electric valve or a solenoid valve.

[0062] like Figure 5 As shown, a second aspect of the embodiments of this application provides a CNC machine tool, including: a bed 200; a spindle box 300, which is vertically and flexibly disposed on the bed 200; and a nitrogen balance system 100 as described in any of the first aspects above.

[0063] For example, the bed 200 may include a base 210, columns 220, and a crossbeam 230. There may be two columns 220, which are arranged parallel to each other on the base 210. The crossbeam 230 is connected between the two columns 220 and can slide up and down along the height direction of the columns 220. The spindle box 300 is disposed on the crossbeam 230. Based on this, the end of the piston rod 122 away from the piston body 121 can be connected to the crossbeam 230 and move up and down synchronously with the crossbeam 230. Correspondingly, the nitrogen balance system 100 can provide a balancing force to the spindle box 300 through the crossbeam 230. In practical applications, the nitrogen balance system 100 can be arranged one-to-one with the column 220. That is, when there are two columns 220, there can also be two nitrogen balance systems 100. The cylinder parts 110 of the two nitrogen balance systems 100 can be respectively set on the two columns 220, and the piston rods 122 of the two nitrogen balance systems 100 can be respectively connected to both ends of the crossbeam 230 to further improve the vertical axis gravity balance performance of the CNC machine tool.

[0064] Furthermore, since the CNC machine tool provided in this application includes the nitrogen balance system 100 as proposed in any of the first aspects above, it possesses all the beneficial effects of the nitrogen balance system 100, which will not be elaborated here.

[0065] In some examples, the control device may also include a user interface, a network interface, a camera, radio frequency (RF) circuitry, sensors, audio circuitry, a Wi-Fi module, and so on. The user interface may include a display screen, input units such as a keyboard, and optional user interfaces may include USB ports, card reader ports, etc. The network interface may include standard wired interfaces, wireless interfaces (such as Wi-Fi interfaces), etc.

[0066] In an exemplary embodiment, the control device may further include an input / output interface and a display device, wherein the various functional units can communicate with each other via a bus. The memory stores a computer program, and the processor executes the program stored in the memory to implement the methods described in the above embodiments.

[0067] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platform, or it can be implemented by hardware.

[0068] In this application, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise expressly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can mean a fixed connection, a detachable connection, or an integral connection; "link" can mean a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0069] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0070] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0071] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A nitrogen balance system (100), characterized in that, For a CNC machine tool, the CNC machine tool includes a bed (200) and a spindle box (300) that is vertically and flexibly disposed on the bed (200), the nitrogen balance system (100) includes: The cylinder section (110) is disposed on the bed (200) and forms a main cavity (1101) and a plurality of auxiliary cavities (1102). The piston section (120) includes a piston body (121) and a piston rod (122). The piston body (121) is slidably disposed in the main cavity (1101) and divides the main cavity (1101) into a rod cavity (1101a) and a rodless cavity (1101b). The piston rod (122) is slidably disposed through the cylinder section (110) and connected between the piston body (121) and the spindle box (300). At least a portion of the piston rod (122) is located in the rod cavity (1101a). Multiple control units (130) are arranged in a one-to-one correspondence with the sub-cavities (1102), and each control unit (130) is used to control one of the sub-cavities (1102) to be turned on or off in the rodless cavity (1101b). A gas supply device (140) is connected to the cylinder section (110) and is used to supply nitrogen gas into the rodless chamber (1101b); The control device (150) is signal-connected to the plurality of the control units (130). The volume of the rodless cavity (1101b) is positively correlated with the position height of the spindle box (300); the control device (150) is used to control the operation of multiple control units (130) so that the number of the secondary cavities (1102) connected to the rodless cavity (1101b) is negatively correlated with the position height of the spindle box (300); The control device (150) includes: The acquisition module is used to obtain the real-time position and height of the spindle box (300); The processing module is used to determine the real-time axial position and actual sliding direction of the piston body (121) in the main cavity (1101) based on the real-time position height of the spindle box (300); The first control module is used to control the plurality of control units (130) to be in a closed state when the piston body (121) is in a first axial position, so that the plurality of secondary chambers (1102) are cut off from the rodless chamber (1101b). The second control module is used to control multiple control units (130) to be in the open state when the piston body (121) is in the second axial position, so that multiple secondary chambers (1102) are connected to the rodless chamber (1101b). The third control module is used to control one of the adjustment units (130) to switch to the open state when the piston body (121) slides a preset distance along the first direction, so that the corresponding secondary chamber (1102) is connected to the rodless chamber (1101b). The fourth control module is used to control one of the adjustment units (130) to switch to the closed state when the piston body (121) slides along the second direction by a preset distance, so that the corresponding secondary chamber (1102) is cut off from the rodless chamber (1101b). Wherein, the first direction is the direction from the first axial position to the second axial position, and the second direction is opposite to the first direction; the preset distance is one-Nth of the distance between the first axial position and the second axial position, where N is the number of the sub-cavities (1102).

2. The nitrogen balance system (100) according to claim 1, characterized in that, The axial direction of the main cavity (1101) is consistent with the height direction of the cylinder (110), the piston body (121) is adapted to slide along the axial direction of the main cavity (1101) between a first axial position and a second axial position, and the rod cavity (1101a) is located between the top end of the cylinder (110) and the rodless cavity (1101b). When the spindle box (300) is in the highest working position, the piston body (121) is in the first axial position, and the volume of the rodless chamber (1101b) is the first volume; when the spindle box (300) is in the lowest working position, the piston body (121) is in the second axial position, and the volume of the rodless chamber (1101b) is the second volume. The multiple sub-cavities (1102) have the same volume, and the sum of the volumes of the multiple sub-cavities (1102) is equal to the difference between the first volume and the second volume.

3. The nitrogen balance system (100) according to claim 1, characterized in that, The nitrogen balance system (100) also includes: Multiple pressure relief sections (160) are disposed in the cylinder section (110) and signal connected to the control device (150). The pressure relief sections (160) are arranged in a one-to-one correspondence with the secondary chambers (1102). Each pressure relief section (160) is used to control one of the secondary chambers (1102) to be open or closed to the external environment. The control device (150) further includes: The fifth control module is used to control the pressure relief section (160) corresponding to the sub-cavity (1102) to open when the sub-cavity (1102) is cut off from the rodless cavity (1101b), so that the sub-cavity (1102) is connected to the external environment until the pressure of the sub-cavity (1102) is consistent with the external environment air pressure.

4. The nitrogen balance system (100) according to claim 1, characterized in that, The nitrogen balance system (100) also includes: A pressure detection device (170) is disposed in the cylinder section (110) and connected to the control device (150). The pressure detection device (170) is used to obtain the actual pressure of the rodless chamber (1101b). The control device (150) is signal-connected to the gas supply device (140), and the control device (150) further includes: The sixth control module is used to control the gas supply device (140) to supply nitrogen gas into the rodless chamber (1101b) when the actual pressure is less than or equal to the preset pressure.

5. The nitrogen balance system (100) according to any one of claims 1 to 4, characterized in that, The cylinder section (110) includes: A cylindrical body (111) is disposed on the bed (200) and forms the main cavity (1101) and a plurality of the secondary cavities (1102). The main cavity (1101) has a first cavity opening and a second cavity opening at both ends, and the secondary cavities (1102) have a third cavity opening and a fourth cavity opening at both ends. The first cavity opening and the third cavity opening are located at the top of the cylindrical body (111), and the second cavity opening and the fourth cavity opening are located at the bottom of the cylindrical body (111). The first end cap (112) is detachably disposed at the top of the cylinder (111). When disposed at the top of the cylinder (111), the first end cap (112) covers the first cavity and the third cavity. The second end cap (113) is detachably disposed at the bottom end of the cylinder (111). When disposed at the bottom end of the cylinder (111), the second end cap (113) covers the second cavity and the fourth cavity. The piston rod (122) is slidably inserted through the first end cap (112).

6. The nitrogen balance system (100) according to claim 5, characterized in that, The cylinder section (110) also includes: A first sealing element is disposed on the first end cap (112). When the first end cap (112) is disposed on the top end of the cylinder (111), the first sealing element is located between the top end of the cylinder (111) and the first end cap (112). The second sealing element is disposed on the second end cap (113). When the second end cap (113) is disposed at the bottom end of the cylinder (111), the second sealing element is located between the bottom end of the cylinder (111) and the second end cap (113). A main pressure relief valve (114) is disposed on the second end cap (113). The main pressure relief valve (114) is used to control the rodless chamber (1101b) to be open or closed to the external environment.

7. The nitrogen balance system (100) according to any one of claims 1 to 4, characterized in that, The control unit (130) includes: A connecting tube (131) is provided, one end of which is connected to the rodless cavity (1101b) and the other end of which is connected to the secondary cavity (1102). A first shut-off valve (132) is disposed on the connecting pipe (131) and signal-connected to the control device (150). The first shut-off valve (132) is used to open or close the connecting pipe (131).

8. The nitrogen balance system (100) according to any one of claims 1 to 4, characterized in that, The gas supply device (140) includes: Gas source section (141); Gas delivery pipe (142), one end of which is connected to the nitrogen output end of the gas source unit (141), and the other end is connected to the rodless cavity (1101b). A second shut-off valve (143) is disposed on the gas supply pipe (142), and the second shut-off valve (143) is used to open or close the gas supply pipe (142).

9. A CNC machine tool, characterized in that, include: Bed frame (200); The spindle box (300) is vertically mounted on the bed (200); The nitrogen balance system (100) as described in any one of claims 1 to 8.

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