Hydrostatic guideway system and method for machine tools

Abstract

The present application relates to the technical field of machine tool processing, and provides a hydrostatic guide rail system and method of a machine tool, the system comprising a controller, a bed base, a slide plate, two hydrostatic guide rails, two hydrostatic sliding parts, two linear motors and two grating rulers, the two hydrostatic guide rails being arranged on the bed base; the slide plate is arranged between the two hydrostatic guide rails through the hydrostatic sliding parts; the two linear motors drive the two sides of the slide plate respectively; the cooling liquid in the cooling liquid flow channels of the two linear motors flows in opposite directions, thereby inhibiting the straightness drift caused by thermal deformation, reducing the frequency of thermal tool setting, and improving the stability of long-time continuous machining precision; in addition, the two grating rulers measure the positions of the two sides of the slide plate respectively, the controller generates a compensation amount based on the position reading difference of the two grating rulers, and controls the two linear motors to generate differential thrust to eliminate the deflection torque, thereby realizing high-precision linear motion of the slide plate.

Description

Technical Field

[0001] This invention relates to the field of machine tool processing technology, and in particular to a hydrostatic guideway system and method for a machine tool. Background Technology

[0002] Ultra-precision five-axis vertical machining centers are key equipment for high-precision machining of complex curved surface parts, optical components and precision molds. Their horizontal motion axes (usually the X-axis or Y-axis that carries the worktable) are the core components for realizing linear feed of the workpiece, and their motion accuracy directly determines the machining accuracy and stability of the whole machine.

[0003] Current ultra-precision five-axis vertical machining centers generally employ linear motor drives paired with rolling guideways for their horizontal motion axes. However, in practical applications, the heat generated by the linear motor and guideway pairs can cause thermal bending deformation of the guideways or machine bed, leading to continuous drift in the straightness of the motion axis during long-term operation. This necessitates frequent thermal tool setting operations, thus affecting machining efficiency and accuracy stability. Furthermore, using a single linear motor to drive the slide is prone to generating deflection torque, which must be passively resisted by the guideway pairs. This not only exacerbates guideway wear but also introduces dynamic positioning errors. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention proposes a hydrostatic guideway system for machine tools to suppress the drift of the linearity of the motion axis caused by thermal deformation and eliminate the deflection torque generated by unilateral drive, thereby achieving high-precision linear motion of the slide.

[0005] This invention also proposes a control method for a hydrostatic guideway system of a machine tool.

[0006] A hydrostatic guideway system for a machine tool according to an embodiment of the present invention includes: Bed base; Two hydrostatic guide rails are provided on the bed base, and the two hydrostatic guide rails extend along a first direction and are arranged in parallel. A slide is positioned between the two hydrostatic guide rails; Two hydrostatic sliding parts are disposed on both sides of the slide along the second direction and are respectively slidably engaged with the two hydrostatic guide rails, wherein the second direction is perpendicular to the first direction; Two linear motors are respectively arranged corresponding to the two hydrostatic guide rails, and are used to drive the two sides of the slide to move along the first direction; each linear motor is equipped with a cooling structure, the cooling structure includes a coolant flow channel extending along the first direction, and the coolant in the coolant flow channel of the two linear motors flows in opposite directions; Two grating rulers are respectively set for the two liquid hydrostatic guide rails, and are used to measure the positions on both sides of the slide. The controller is electrically connected to the two linear motors and the two grating rulers respectively; the controller is configured to: control the movement position of the slide along the first direction based on the position readings measured by the two grating rulers; and determine the difference between the position readings measured by the two grating rulers, and if the difference exceeds a set threshold, generate a position compensation amount based on the difference, and use the position compensation amount to adjust the control commands of the two linear motors respectively to reduce the difference.

[0007] According to one embodiment of the present invention, each of the liquid hydrostatic sliding parts includes two hydrostatic sliders arranged at intervals along the first direction, and each hydrostatic slider has an oil cavity on its sliding surface, and a throttle is disposed in the oil cavity.

[0008] According to one embodiment of the present invention, the two hydrostatic guide rails are arranged symmetrically about the central axis of the slide moving in the first direction, and the two linear motors are arranged symmetrically about the central axis of the slide moving in the first direction.

[0009] According to one embodiment of the present invention, the oil supply lines of the two hydrostatic sliding parts are of equal length.

[0010] According to one embodiment of the present invention, the middle part of the slide is recessed downward to form a mounting cavity, a rotary shaft is provided in the mounting cavity, and a worktable for carrying a workpiece is mounted on the rotary shaft. The support surface of the worktable and the lower surface of the hydrostatic sliding part are located in the same horizontal plane.

[0011] According to one embodiment of the present invention, the mounting cavity is provided with reinforcing ribs.

[0012] According to one embodiment of the present invention, the linear motor includes: A stator is disposed on the bed base. The stator includes a non-magnetic insulating frame and coil windings wound on the non-magnetic insulating frame. The stator is provided with the coolant flow channel. The mover, in conjunction with the stator, is disposed on the slide.

[0013] According to one embodiment of the present invention, a heat insulation element is provided between the stator and the slide.

[0014] According to one embodiment of the present invention, the outer surface of the slide is coated with a heat-insulating coating.

[0015] A control method for a hydrostatic guideway system of a machine tool according to an embodiment of the present invention, applied to the hydrostatic guideway system of any one of the above-described machine tools, the method comprising: Obtain the position readings measured by the two grating rulers; Determine the average value of the two position readings, and control the movement position of the slide along the first direction based on the average value; Determine the difference between the position readings measured by the two grating rulers; If the difference exceeds a set threshold, a position compensation amount is generated based on the difference; The control commands of the two linear motors are adjusted using the position compensation amount to reduce the difference.

[0016] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: By setting two linear motors to drive both sides of the slide respectively, and configuring coolant channels with opposite flow directions, the temperature rise rate of the motors on both sides is made to be more consistent. This maintains a symmetrical temperature field distribution in the bed base and hydrostatic guide rail, effectively suppressing the drift of the motion axis straightness caused by thermal deformation, reducing the frequency of thermal tool setting, and improving the accuracy and stability of long-term continuous machining. At the same time, the controller generates a position compensation amount based on the position reading difference of the two grating rulers, and regulates the two linear motors to generate differential thrust to eliminate the deflection torque. This eliminates the influence of the deflection torque on the uniformity of the oil film between the hydrostatic guide rail and the hydrostatic sliding part, thereby achieving high-precision linear motion of the slide.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention and are not considered as limitations on this application. Moreover, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0019] Figure 1 This is one of the schematic structural diagrams of the hydrostatic guide rail system for machine tools provided by the present invention.

[0020] Figure 2 This is the second schematic structural diagram of the hydrostatic guide rail system for machine tools provided by the present invention.

[0021] Figure 3 This is one of the partial schematic structural diagrams of the hydrostatic guide rail system for machine tools provided by the present invention.

[0022] Figure 4This is the second partial schematic structural diagram of the hydrostatic guide rail system for machine tools provided by the present invention.

[0023] Figure 5 This is a schematic structural diagram of the motion unit provided by the present invention.

[0024] Figure 6 yes Figure 5 A magnified schematic diagram of the structure at point A.

[0025] Figure label: 100. Bed base; 110. Base; 120. Vibration damping component; 130. Support component; 200. Motion unit; 210. Hydrostatic guide rail; 211. Oil guide groove; 220. Slide plate; 221. Mounting cavity; 222. Reinforcing rib; 230. Hydrostatic sliding part; 231. Hydrostatic slider; 240. Linear motor; 241. Stator; 250. Grating ruler; 251. Scale; 252. Reading head; 260. Thermal insulation components; 270. Protective components; 271. Fixed cover; 272. Flexible telescopic protective cover; 273. End plate; 280. Oil collection components; 290. Guide rail pressure plate. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] The specific terms used in this specification are for illustrative purposes only and are not intended to limit the illustrated embodiments. For example, expressions such as "same" and "identical" not only indicate a strictly identical state, but also indicate a state with tolerances or differences in the degree of functionality. For example, expressions indicating relative or absolute arrangement such as "in a certain direction," "along a certain direction," "side by side," "perpendicular," "centered on," "concentric," or "coaxial" not only strictly indicate such an arrangement, but also indicate a state of relative displacement by tolerances or angles or distances with the same degree of functionality.

[0028] The terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0029] Furthermore, features specified as "first" or "second" may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "multiple" means two or more. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified. In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, B1 and / or B2 can represent: B1 existing alone, B1 and B2 existing simultaneously, and B2 existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The following is combined with Figures 1 to 6 The present invention describes a hydrostatic guideway system and method for a machine tool.

[0032] Embodiments of the present invention provide a hydrostatic guideway system for machine tools, such as... Figures 1 to 5 As shown, the system includes a bed base, a motion unit, and a controller.

[0033] The bed base 100 is the basic support component of the machine tool. It can be cast or assembled from high-strength natural granite or other materials, and has high rigidity and good thermal stability. The upper surface of the bed base 100 is precision machined to form an installation reference surface for mounting the various components of the motion unit 200.

[0034] The motion unit 200 is disposed on the bed base 100 and includes a slide 220, two hydrostatic guide rails 210, two hydrostatic sliding parts 230, two linear motors 240, and two grating rulers 250. The two hydrostatic guide rails 210 are disposed on the upper surface of the bed base 100, extending along a first direction (e.g., the horizontal X direction) and arranged parallel to each other. The slide 220 spans between the two hydrostatic guide rails 210 and can reciprocate relative to the bed base 100 and the hydrostatic guide rails 210 along the first direction. The slide 220 is used to support workpieces, rotary shafts, or other functional components.

[0035] Two hydrostatic sliding parts 230 are respectively disposed on both sides of the slide 220 along a second direction, which is perpendicular to the first direction. That is, hydrostatic sliding parts 230 are provided on both sides of the slide 220 along the second direction. Each hydrostatic sliding part 230 slides in cooperation with a corresponding hydrostatic guide rail 210 to achieve reciprocating motion of the slide 220 relative to the bed base 100 along the first direction. During operation, pressurized oil enters the oil chamber of the hydrostatic sliding part 230, forming a high-pressure oil film between the hydrostatic sliding part 230 and the hydrostatic guide rail 210, which floats the slide 220, achieving a nearly frictionless and stable linear motion.

[0036] Two linear motors 240 are respectively set to correspond to two hydrostatic guide rails 210, and are used to drive the two sides of the slide 220 to move along the first direction. That is, the two linear motors 240 each drive one side of the slide 220 to move along the first direction, thereby realizing the synchronous driving of both sides of the slide 220.

[0037] To prevent motor overheating from affecting guide rail accuracy, each linear motor 240 is equipped with a cooling structure. Specifically, the cooling structure includes a coolant channel extending along a first direction, which can be located inside the stator 241 housing or the bed base. During operation, the coolant circulates within the channel, carrying away the heat generated by the motor. It should be noted that the coolant flows in opposite directions within the coolant channels of the two linear motors 240; for example, the coolant in one linear motor 240 flows from front to back, while the coolant in the other linear motor 240 flows from back to front. This reverse flow design ensures that the temperature rise rate of both linear motors 240 is consistent, thereby maintaining a symmetrical temperature distribution in the bed base 100 and the two hydrostatic guide rails 210, effectively suppressing thermal bending deformation caused by temperature differences.

[0038] Two grating rulers 250 are respectively set for the two hydrostatic guide rails 210. The two sets of grating rulers 250 work independently to measure the position of both sides of the slide 220. Therefore, in this embodiment, two linear motors 240 are used to drive both sides of the slide 220 independently, and two independent grating rulers 250 are equipped to provide feedback on the position information of both sides of the slide 220, forming a dual-drive, dual-feedback structure. This eliminates the deflection torque generated by single-sided drive, and enables the system of this embodiment to achieve high acceleration and high positioning accuracy.

[0039] The controller is electrically connected to two linear motors 240 and two grating rulers 250 respectively. The controller is configured to: control the movement position of the slide 220 along a first direction based on the position readings measured by the two grating rulers 250; and determine the difference between the position readings measured by the two grating rulers 250. If the difference exceeds a set threshold, the controller generates a position compensation amount based on the difference and uses the position compensation amount to adjust the control commands of the two linear motors 240 respectively to drive the two linear motors 240 to generate differential thrust, thereby reducing the difference.

[0040] Understandably, the controller obtains the average position readings measured by the two grating rulers 250 as the actual position of the slide 220, and compares this actual position with the target position to obtain the position deviation. Based on this position deviation, the controller generates drive commands through the position adjuster and outputs them to the drivers of the two linear motors 240, driving the slide 220 to move to reduce the position deviation, so that the actual position of the slide 220 follows the target position in real time, thereby forming a position closed-loop control.

[0041] The controller determines in real time the difference between the position readings measured by the two grating rulers 250. This difference reflects the degree of asynchrony in the movement of the two sides of the slide 220, i.e., the possible deflection of the slide 220 in the horizontal plane. When this difference exceeds a set threshold, the controller generates a position compensation amount based on the magnitude and direction of the difference. Using this position compensation amount, the controller adjusts the control commands of the two linear motors 240, causing the two motors to generate differential thrust. Specifically, one linear motor 240 increases its thrust, while the other decreases its thrust, thereby generating an active correction torque that reduces the difference in position readings measured by the two grating rulers 250 to within an acceptable range. Thus, this embodiment not only achieves high-precision positioning of the slide 220 but also suppresses deflection torque through active differential thrust, eliminating the deficiency of the single-sided drive method that relies on the guide rail's passive resistance torque. This allows the straightness of the slide 220 moving along the first direction to reach the sub-micron level, significantly improving the guiding accuracy of horizontal movement.

[0042] In this embodiment, during system operation, the controller receives real-time position feedback (i.e., position readings) from two grating rulers 250, calculates the average of the two position readings as the actual position of the slide 220, and compares this actual position with the target position to form a position closed-loop control, outputting basic drive commands to the two linear motors 240. Simultaneously, the controller continuously monitors the difference between the position readings measured by the two grating rulers 250. When this difference exceeds a set threshold, a compensation amount is generated and superimposed on the basic drive command, causing the two linear motors 240 to generate differential thrust, actively correcting the deflection torque error. Coolant flows in opposite directions in the coolant channels corresponding to the two linear motors 240, maintaining a consistent temperature on both sides. Pressurized oil enters the oil chamber of the hydrostatic sliding part 230 through the oil supply system to form a bearing oil film between the hydrostatic sliding part 230 and the hydrostatic guide rail 210, allowing the slide 220 to slide smoothly in a near-zero friction state.

[0043] The hydrostatic guideway system for the machine tool provided in this embodiment of the invention uses two linear motors 240 to drive both sides of the slide 220 respectively, and configures coolant channels with opposite flow directions. This makes the temperature rise rate of the motors on both sides tend to be consistent, thereby maintaining a symmetrical temperature field distribution between the bed base 100 and the hydrostatic guideway 210. This effectively suppresses the drift of the linearity of the motion axis caused by thermal deformation, reduces the frequency of thermal tool setting, and improves the accuracy and stability of long-term continuous machining. At the same time, the controller generates a position compensation amount based on the position reading difference of the two grating rulers 250, and regulates the two linear motors 240 to generate differential thrust to eliminate the deflection torque. This eliminates the influence of the deflection torque on the oil film uniformity between the hydrostatic guideway 210 and the hydrostatic sliding part 230, thereby achieving high-precision linear motion of the slide 220.

[0044] In one embodiment of the present invention, in order to achieve symmetry of the temperature field and suppress thermal drift, the two hydrostatic guide rails 210, the two linear motors 240, and the two grating rulers 250 are all arranged symmetrically about the motion axis of the slide 220. Specifically, the two hydrostatic guide rails 210 are symmetrically arranged on the bed base 100 with reference to the central axis of the slide 220 moving in the first direction, so that the support stiffness on both sides of the slide 220 is consistent; the two linear motors 240 are also symmetrically arranged about the central axis of the slide 220 moving in the first direction, and are respectively fixed on the bed base 100 on both sides of the slide 220, ensuring that the resultant force of the driving force on both sides passes through the center of mass of the slide 220 and avoids generating additional deflection torque; the two grating rulers 250 are symmetrically arranged about the central axis of the slide 220 moving in the first direction, and are respectively installed on both sides of the slide 220 for independently measuring the position information on both sides of the slide 220.

[0045] In one embodiment of the present invention, each hydrostatic sliding part 230 includes a plurality of hydrostatic sliders 231 arranged at intervals along a first direction, and each hydrostatic slider 231 has an oil cavity on its sliding surface.

[0046] Optionally, each oil chamber of the hydrostatic slider 231 is equipped with a throttle, through which pressurized oil enters the oil chamber and forms a high-pressure oil film between the hydrostatic slider 231 and the hydrostatic guide rail 210.

[0047] Among them, the throttle can be a thin-film feedback throttle, which can automatically adjust the throttle ratio according to the load change, so that the high-pressure oil film has adaptive compensation characteristics, thereby maintaining stable oil film stiffness and thickness under variable load conditions.

[0048] In this embodiment, as Figure 5 As shown, the slide 220 has a rectangular cross-section along the horizontal direction. Each hydrostatic sliding part 230 includes two hydrostatic sliders 231, totaling four hydrostatic sliders 231, which are arranged at the four corners of the slide 220, forming a rectangular support layout. This layout distributes the support points of the slide 220 at the four corners, forming a wide-base support structure, which can effectively resist the overturning moment caused by the shift of the center of gravity, cutting force, or inertial force during the movement of the slide 220, thus enhancing the stability of the movement. At the same time, the four hydrostatic sliders 231 are symmetrically distributed on both sides of the slide 220, making the support stiffness on both sides consistent, which is beneficial to maintaining the movement accuracy of the slide 220 along the first direction. When the slide 220 is subjected to vertical load or deflection load, the four hydrostatic sliders 231 share the load, avoiding local overload and improving the overall load-bearing capacity and stiffness of the system. Furthermore, this layout, combined with the symmetrical structure of the dual linear motors 240 and dual grating rulers 250, makes the entire motion unit 200 more compact and the force more balanced, providing a reliable foundation for achieving high-precision, high-acceleration motion.

[0049] Optionally, the hydrostatic guide rail 210 has an L-shaped cross-section, comprising a mutually perpendicular horizontal base and vertical sidewalls, forming two precision guide surfaces for sliding engagement with the bottom and side surfaces of the hydrostatic slider 231. The hydrostatic slider 231 is mounted on the hydrostatic guide rail 210, and oil chambers are provided on both its bottom and side surfaces. When pressurized oil enters the oil chambers through the throttle, a high-pressure oil film is formed between the hydrostatic slider 231 and the hydrostatic guide rail 210, lifting the hydrostatic slider 231 and the slide plate 220, achieving nearly frictionless and smooth linear motion.

[0050] Furthermore, such as Figure 3 and Figure 4As shown, this embodiment also includes a guide rail pressure plate 290 on the hydrostatic guide rail 210, and an oil cavity on the top surface of the hydrostatic slider 231. The guide rail pressure plate 290 is fixedly installed above the hydrostatic guide rail 210, opposite to the top surface of the hydrostatic slider 231. When pressurized oil enters the oil cavity on the top surface of the hydrostatic slider 231 through the throttle, a high-pressure oil film is formed between the top surface of the hydrostatic slider 231 and the guide rail pressure plate 290. Thus, high-pressure oil films are formed on the bottom, side, and top surfaces of the hydrostatic slider 231, meaning the sliding surface of the hydrostatic slider 231 is covered by the oil film. In this way, the hydrostatic slider 231 is supported and constrained by the oil film in all directions, forming a closed hydrostatic structure, which improves the overall rigidity and load-bearing capacity of the guide rail system. Simultaneously, the oil films in each direction can effectively absorb and suppress cutting forces and inertial forces from different directions, enhancing the system's vibration resistance.

[0051] In one embodiment of the present invention, such as Figure 5 and Figure 6 As shown, the upper part of the hydrostatic guide rail 210, near the slide plate 220, has a rectangular notch. This notch forms two mutually perpendicular guide surfaces in cross-section: a horizontal base and a vertical sidewall, for sliding engagement with the bottom and side surfaces of the hydrostatic slider 231. The lower part of the hydrostatic guide rail 210, near the slide plate 220, has a vertically extending through groove. This through groove serves as an oil guide groove 211, guiding the oil flowing between the hydrostatic slider 231 and the hydrostatic guide rail downwards. An oil collector 280 is located below the hydrostatic guide rail 210. The oil collector 280 has an oil collection cavity located directly below the oil guide groove 211, for collecting the oil flowing down from the oil guide groove 211, thus achieving the recovery and recycling of lubricating oil.

[0052] In one embodiment of the present invention, such as Figure 2 As shown, the motion unit 200 also includes two protective components, corresponding to the two hydrostatic guide rails 210 respectively; each protective component includes a fixed cover 271, a flexible telescopic protective cover 272, and two end plates 273. The fixed cover 271 is a long strip-shaped shell, covering the corresponding hydrostatic guide rail 210 and extending along the first direction. The two end plates 273 are fixed to both ends of the fixed cover 271 respectively, and the flexible telescopic protective cover 272 is disposed between the end plates 273 and the fixed cover 271, and is telescopic along the first direction; the end plates 273, the flexible telescopic protective cover 272, and the fixed cover 271 together form a protective cavity, in which the linear motor 240, the hydrostatic guide rail 210, and the hydrostatic sliding part 230 are all located to prevent external contaminants such as chips and coolant from entering. The fixed cover 271 has an opening groove extending in the first direction. The slide plate 220 passes through the opening groove and is slidably fitted with the corresponding hydrostatic guide rail 210. The length and width of the opening groove match the movement stroke and contour of the slide plate 220 to realize the relative movement between the protective component and the slide plate 220.

[0053] In one embodiment of the present invention, the oil supply lines of the two hydrostatic sliding parts 230 are arranged in the same direction, that is, the lengths of the oil supply lines of the two hydrostatic sliding parts 230 are equal, so as to ensure that the hydrostatic oil flow path lengths supplied to the two hydrostatic sliding parts 230 are consistent, thereby making the oil temperature entering the two hydrostatic sliding parts 230 the same.

[0054] In this embodiment, each hydrostatic sliding part 230 includes two hydrostatic sliders 231, for a total of four hydrostatic sliders 231. Each hydrostatic slider 231 is supplied with oil by an independent oil supply line, and the four oil supply lines are of equal length and have the same diameter. Therefore, the oil supply pressure loss and oil temperature rise of the four hydrostatic sliders 231 remain consistent, ensuring uniform oil film stiffness in each slider, and further improving the smoothness and accuracy of the slide plate 220's movement.

[0055] In one embodiment of the present invention, such as Figure 5 As shown, the middle part of the slide 220 is recessed downward to form a mounting cavity 221. The mounting cavity 221 is used to set components such as a rotary shaft. A worktable for carrying the workpiece is mounted on the rotary shaft. The support surface of the worktable and the lower surface of the hydrostatic sliding part 230 are located in the same horizontal plane.

[0056] Optionally, to further increase the structural rigidity of the mounting cavity 221 and prevent deformation due to load concentration, a reinforcing rib 222 is provided inside the mounting cavity 221.

[0057] In this embodiment, the main body of the slide plate 220 has a hollow box-shaped structure with intersecting diagonal reinforcing ribs 222 inside, similar to the ribs of a ship's hull, to reduce the mass of the slide plate 220 while ensuring sufficient rigidity. The slide plate 220 narrows in a streamlined shape at both ends perpendicular to the first direction, forming a lightweight ship-shaped structure, thereby reducing motion inertia, improving the dynamic response capability of the system, and facilitating high-acceleration motion.

[0058] The slide plate 220 has a downwardly recessed central section forming a mounting cavity 221. A rotating shaft is housed within the mounting cavity 221, and a worktable (i.e., a cradle seat) for supporting the workpiece is mounted on the rotating shaft. The vertical height of the support surface (i.e., the upper surface) of this worktable is lowered, so that the support surface and the lower surface of the hydrostatic sliding part 230 are on the same horizontal plane. The lower surface of the hydrostatic sliding part 230 is the oil film surface where the hydrostatic slider 231 contacts the hydrostatic guide rail 210. This coplanar design geometrically eliminates the overturning moment caused by the shift in the center of gravity, ensuring uniform oil film thickness, improving motion stability, and extending the service life of the guide rail.

[0059] The two sides of the slide plate 220 are used to fix the hydrostatic sliding part 230 to ensure the precise fit between the hydrostatic slider 231 and the hydrostatic guide rail 210.

[0060] The hydrostatic guide rail system for machine tools provided by this invention achieves a symmetrical thermal balance design by symmetrically arranging two hydrostatic guide rails 210, two linear motors 240, and two grating rulers 250 about the central axis of the slide 220's movement direction, with the coolant flowing in opposite directions for the two linear motors 240, the oil supply lines adopting a parallel layout, and a heat insulation layer being installed. This reduces the temperature difference in the motion unit 200, effectively suppressing the drift in the linearity of the motion axis caused by thermal deformation. The dual-drive, dual-closed structure, where two linear motors 240 independently drive both sides of the slide 220 and are equipped with two independent grating rulers 250 to provide position information from both sides of the slide 220, allows the controller to generate compensation based on the position reading difference between the two grating rulers 250, thereby controlling the differential thrust generated by the two linear motors 240. This eliminates the deflection torque generated by single-sided drive, achieving both high acceleration and high positioning accuracy. The lightweight, boat-shaped slide 220 reduces its mass, improves dynamic response, and shortens acceleration and deceleration times. Furthermore, the coplanar design of the worktable support surface and the lower surface of the hydrostatic slider 231, where the worktable support surface and the lower surface of the hydrostatic slider 230 are on the same horizontal plane, eliminates the overturning torque caused by center of gravity shift, ensures uniform oil film thickness, and extends service life. This enables the horizontal motion axis to achieve high straightness and high acceleration, providing support for the five-axis linkage machining accuracy of the whole machine.

[0061] In one embodiment of the present invention, the linear motor 240 is a coreless water-cooled type.

[0062] For example, the linear motor 240 is a coreless, water-cooled type. Specifically, such as... Figure 5 As shown, the linear motor 240 includes a stator 241 and a mover. The stator 241 is fixed to the bed base 100 and extends along a first direction. It includes a non-magnetic insulating frame and coil windings wound on the non-magnetic insulating frame. The stator 241 is also provided with a coolant flow channel. The mover cooperates with the stator 241 and is fixedly mounted on the slide 220.

[0063] In this embodiment, the cooling structure is located at the mating position between the bed base 100 and the stator 241. Specifically, the coolant channel is located inside the bed base 100, and both ends of the coolant channel are connected to an external cooling circulation system. By introducing coolant into the coolant channel, the linear motor 240 is circulated for heat dissipation, thereby controlling the temperature rise of the linear motor 240 during operation. It should be noted that in other embodiments, the coolant channel may also be located in the housing of the stator 241, or simultaneously located in both the stator 241 and the bed base 100.

[0064] In one embodiment of the present invention, such as Figure 3 As shown, two grating rulers 250 are respectively set for two hydrostatic guide rails 210. Each grating ruler 250 includes a scale 251 and a reading head 252, wherein the reading head 252 is fixedly mounted on a stationary component, such as the bed base 100 or the guide rail pressure plate 290, and the scale 251 is fixed along a first direction on the slide 220 or the hydrostatic sliding part 230 and moves with the slide 220. The resolution of the grating rulers 250 can reach the nanometer level, and is used to measure the position information on both sides of the slide 220. The two sets of grating rulers 250 work independently, respectively outputting real-time position signals on both sides of the slide 220.

[0065] It should be noted that in other embodiments, the installation positions of the scale 251 and the reading head 252 can also be interchanged, that is, the scale 251 is fixed while the reading head 252 moves with the slide 220, as long as the relative displacement between the two can be measured.

[0066] In one embodiment of the present invention, such as Figure 5 and Figure 6 As shown, a heat insulation component 260 is provided between the stator 241 and the slide 220. Specifically, a heat insulation component 260 is provided between the stator 241 and the slide 220 of both linear motors 240, and the two heat insulation components 260 have the same thickness and material to block the heat generated by the stator 241 from being transferred to the slide 220, thereby reducing the impact of thermal deformation on motion accuracy.

[0067] It should be noted that a heat insulation layer is also provided between the stator 241 of the two linear motors 240 and the bed base 100, and the two heat insulation layers have the same thickness and material to block the heat generated by the stator 241 from being transferred to the bed base 100 and to maintain the symmetrical distribution of the bed temperature field.

[0068] In one embodiment of the present invention, the outer surface of the slide 220 is coated with a heat-insulating coating to further reduce the thermal impact of ambient temperature changes and external heat sources on the slide 220 and improve the thermal stability of the guide rail system.

[0069] In one embodiment of the present invention, such as Figure 1As shown, the bed base 100 includes a base 110 and leg assemblies for supporting the base 110. There are two sets of leg assemblies, respectively located at both ends of the base 110 along a second direction, and the two sets of leg assemblies are symmetrically arranged about the central axis of the slide's movement along a first direction. Each set of leg assemblies includes three legs spaced apart along the first direction. Each leg includes a damper 120 and a support 130, wherein the support 130 is a shim, and the damper 120 is disposed between the shim and the base 110. A through mounting groove extending along the first direction is provided on the bottom surface of the base 110 for mounting the leg assemblies.

[0070] Based on the hydrostatic guideway system for machine tools provided in any of the above embodiments, embodiments of the present invention also propose a control method for the hydrostatic guideway system for machine tools, the method comprising the following steps: S1. Obtain the position readings measured by the two grating rulers.

[0071] S2. Determine the average value of the two position readings, and control the movement of the slide along the first direction based on the average value.

[0072] S3. Determine the difference between the position readings measured by the two grating rulers.

[0073] S4. If the difference exceeds the set threshold, generate a position compensation amount based on the difference.

[0074] S5. Use position compensation to adjust the control commands of the two linear motors respectively to reduce the difference.

[0075] Understandably, the process involves acquiring position readings from two grating rulers; determining the average of the two position readings; comparing this average with the target position of the slide; generating a drive command based on the position deviation obtained from the comparison; controlling the slide to move along a first direction; ensuring that the actual position follows the target position in real time; and thus forming a closed-loop position control. Simultaneously, the difference between the position readings measured by the two grating rulers is determined in real time. When this difference exceeds a set threshold, a position compensation amount is generated based on the magnitude and direction of the difference. This compensation amount is then used to adjust the control commands of the two linear motors, causing one linear motor to increase thrust and the other to decrease thrust, generating differential thrust to reduce the difference.

[0076] Finally, it should be noted that the above embodiments are only for illustrating the present invention and not for limiting the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be covered within the scope of the claims of the present invention.

Claims

1. A hydrostatic guideway system for a machine tool, characterized in that, include: Bed base; Two hydrostatic guide rails are provided on the bed base, and the two hydrostatic guide rails extend along a first direction and are arranged in parallel. A slide is positioned between the two hydrostatic guide rails; Two hydrostatic sliding parts are disposed on both sides of the slide along the second direction and are respectively slidably engaged with the two hydrostatic guide rails, wherein the second direction is perpendicular to the first direction; the oil supply lines of the two hydrostatic sliding parts are of equal length. Two linear motors are respectively arranged corresponding to the two hydrostatic guide rails, and are used to drive the two sides of the slide to move along the first direction; each linear motor is equipped with a cooling structure, the cooling structure includes a coolant flow channel extending along the first direction, and the coolant in the coolant flow channel of the two linear motors flows in opposite directions; Two grating rulers are respectively set for the two liquid hydrostatic guide rails, and are used to measure the positions on both sides of the slide. The controller is electrically connected to the two linear motors and the two grating rulers respectively; the controller is configured to control the movement position of the slide along the first direction based on the position readings measured by the two grating rulers; And determine the difference between the position readings measured by the two grating rulers. If the difference exceeds a set threshold, generate a position compensation amount based on the difference, and use the position compensation amount to adjust the control commands of the two linear motors respectively to reduce the difference.

2. The hydrostatic guideway system for a machine tool according to claim 1, characterized in that, Each of the liquid hydrostatic sliding parts includes two hydrostatic sliders arranged at intervals along the first direction, and each hydrostatic slider has an oil cavity on its sliding surface, and a throttle is provided in the oil cavity.

3. The hydrostatic guideway system for a machine tool according to claim 1, characterized in that, The two hydrostatic guide rails are arranged symmetrically about the central axis of the slide moving in the first direction, and the two linear motors are arranged symmetrically about the central axis of the slide moving in the first direction.

4. The hydrostatic guideway system for a machine tool according to claim 1, characterized in that, The middle part of the slide is recessed downward to form a mounting cavity. A rotating shaft is provided in the mounting cavity, and a worktable for carrying the workpiece is mounted on the rotating shaft. The support surface of the worktable and the lower surface of the hydrostatic sliding part are located in the same horizontal plane.

5. The hydrostatic guideway system for a machine tool according to claim 4, characterized in that, The mounting cavity is equipped with reinforcing ribs.

6. The hydrostatic guideway system for a machine tool according to claim 1, characterized in that, The linear motor includes: A stator is disposed on the bed base. The stator includes a non-magnetic insulating frame and a coil winding wound on the non-magnetic insulating frame. The stator is provided with the coolant flow channel. The mover, in conjunction with the stator, is disposed on the slide.

7. The hydrostatic guideway system for a machine tool according to claim 6, characterized in that, A heat insulation component is provided between the stator and the slide.

8. The hydrostatic guideway system for a machine tool according to any one of claims 1 to 7, characterized in that, The outer surface of the slide is coated with a heat-insulating coating.

9. A control method for a hydrostatic guideway system of a machine tool, characterized in that, The method, applied to the hydrostatic guideway system of the machine tool according to any one of claims 1 to 8, comprises: Obtain the position readings measured by the two grating rulers; Determine the average value of the two position readings, and control the movement position of the slide along the first direction based on the average value; Determine the difference between the position readings measured by the two grating rulers; If the difference exceeds a set threshold, a position compensation amount is generated based on the difference; The control commands of the two linear motors are adjusted using the position compensation amount to reduce the difference.

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