Supporting mechanism of large-span ball screw

Abstract

The invention discloses a supporting mechanism for a large-span ball screw, which belongs to the technical field of ball screw supporting mechanisms and comprises a supporting wheel group, a supporting wheel group, a supporting wheel group, a supporting wheel group and a supporting wheel group, and the supporting wheel group is tangent to the ball screw; the abutting assembly is installed below the supporting wheel set and used for applying abutting force for abutting against the ball screw to the supporting wheel set; the downward pressing part is mounted on a lead screw nut which is in threaded connection with the ball screw; when the lead screw nut passes through the upper portion of the supporting wheel set, the downward pressing part exerts downward pressing force on the supporting wheel set, so that the supporting wheel set is made to leave the position, and continuous and adjustable upward supporting force can be provided for the large-span ball screw according to the gas-liquid pressurization principle; the supporting mechanism can achieve automatic pressing avoiding when the lead screw nut passes through and rapid resetting after the lead screw nut passes through without an additional sensor or a power source, and compared with a traditional linear sliding rail supporting mode, the system complexity and the maintenance cost are remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of ball screw support mechanism technology, and specifically to a support mechanism for a large-span ball screw. Background Technology

[0002] With the continuous upgrading and progress of the CNC machine tool manufacturing industry, machine tools are becoming larger and larger. Consequently, ball screws, as the main transmission components, are also becoming longer and longer. However, the increase in the length of ball screws brings about many problems, with disadvantages concentrated in structural stability, precision control, and manufacturing costs, as detailed below: Low critical speed makes resonance easy: the critical speed decreases significantly with the increase of span. High-speed operation is prone to approaching the natural resonance frequency, causing bending resonance, which can lead to structural failure in severe cases.

[0003] Poor structural rigidity and easy deformation: The length-to-diameter ratio is easy to exceed the critical value. Its own weight will cause the lead screw to sag and deform, and will also amplify dynamic instability. This will not only reduce positioning accuracy, but also aggravate off-center wear, and even cause permanent deformation.

[0004] Transmission components are prone to failure: When the ball recirculation structure of the nut is running at high speed, it is prone to problems such as breakage of the ball picker teeth or ball jamming due to impact load. In addition, the reduction in the number of balls will also significantly reduce the static stiffness of the feed system.

[0005] High cost and process requirements: The heat treatment and precision grinding processes during manufacturing are difficult to control and are prone to defects such as cracks; Subsequent maintenance requires regular maintenance and replacement of parts, and optimization measures to solve problems such as deflection will increase costs.

[0006] Accuracy is easily affected: If performance is improved by increasing the preload, it will lead to changes in pitch, shorten the life of the lead screw, and may also increase motion noise.

[0007] To reduce the aforementioned problems, ball screw auxiliary support mechanisms are now added to support the ball screw with a large span, ensuring stability, rigidity, and accuracy under high-speed operating conditions.

[0008] Traditional lead screw support methods typically employ linear guides and adjusting shims, which require high manufacturing precision and are costly. To address the problems of traditional lead screw support methods, this invention provides a support mechanism for a large-span ball screw. Summary of the Invention

[0009] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a support mechanism for a large-span ball screw that utilizes the principle of gas-liquid pressurization to provide a continuous and adjustable upward support force to the large-span ball screw. This mechanism achieves automatic downward pressure to avoid the screw nut during passage and rapid reset after passage without the need for additional sensors or power sources. Compared to traditional linear guide rail support methods, this significantly reduces system complexity and maintenance costs.

[0010] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention provides a support mechanism for a large-span ball screw, comprising: A support wheel assembly, which is tangent to the ball screw; A clamping assembly, which is installed below the support wheel assembly, is used to apply a clamping force to the support wheel assembly to clamp the ball screw; The pressing part is installed on the screw nut threaded onto the ball screw; When the lead screw nut passes over the support wheel assembly, the downward pressure part applies downward pressure to the support wheel assembly, causing the support wheel assembly to move aside.

[0011] Preferably, the support wheel assembly includes: The base frame is a rectangular frame with an opening on the top, and the base frame is located below the ball screw; Two support shafts are rotatably mounted inside both ends of the base frame, and the axes of the support shafts are parallel to the axis of the ball screw, and the two support shafts are tangent to the ball screw. The guide portion is installed on both ends of the base frame and is adapted to the pressing portion.

[0012] Preferably, the guide portion includes: Two rollers are rotatably mounted on the two end faces of the base frame.

[0013] Preferably, the pressing part includes: A base sleeve, which is fixedly installed on the outside of the lead screw nut; Two fixing plates are respectively fixedly installed on both sides of the base sleeve. When the lead screw nut passes over the support wheel assembly, the fixing plates apply a downward clamping force to the roller.

[0014] Preferably, the lower side of the fixing plate has two ends that are inclined upwards.

[0015] Preferably, the upper side of the base frame is provided with a groove adapted to the ball screw.

[0016] Preferably, the clamping component includes: The pressure supply unit is used to provide a power source; A hydraulic cylinder assembly, wherein the piston rod of the hydraulic cylinder assembly is connected to a support wheel assembly via a connecting part; The pressure supply unit pressurizes the hydraulic oil inside the hydraulic cylinder assembly, causing the piston rod of the hydraulic cylinder assembly to extend and apply an upward clamping force to the support wheel assembly.

[0017] Preferably, the pressure supply unit includes: A nitrogen accumulator, one end of which is connected to a nitrogen source via a gas valve, and the other end of which is connected to a hydraulic cylinder assembly via an oil valve.

[0018] Preferably, the nitrogen accumulator comprises: The housing has a piston slidably mounted inside it. The piston divides the internal space of the housing into a gas storage space for storing nitrogen and an oil storage space for storing oil. The piston slides inside the housing to achieve the extension and retraction of the piston rod of the hydraulic cylinder assembly.

[0019] Preferably, the connecting portion includes: The base plate is fixedly mounted on the support wheel assembly; Multiple protruding elastic rods, the two ends of which are respectively fixedly connected to the piston rod of the base plate and the hydraulic cylinder assembly; Multiple concave spring rods, with both ends of the multiple concave spring rods being fixedly connected to the piston rod of the base plate and the hydraulic cylinder assembly, respectively; Among them, multiple convex elastic rods and multiple concave elastic rods are evenly distributed along the circumference of the piston rod of the hydraulic cylinder assembly, and the multiple convex elastic rods and multiple concave elastic rods are staggered. An elastic rod is fixedly installed between the convex elastic rods and the concave elastic rods. The cross-section of the elastic rod is elliptical and the elastic rod is designed as a hollow structure.

[0020] The beneficial effects of this invention are as follows: This invention utilizes a nitrogen accumulator, a hydraulic cylinder assembly, and a fixed plate with an inclined surface and a guide roller to provide continuous and adjustable upward support force to a large-span ball screw using the principle of gas-liquid pressurization. This effectively counteracts the deflection deformation caused by the screw's own weight and prevents resonance during high-speed operation. Simultaneously, by utilizing the mechanical cooperation between the inclined surface of the fixed plate and the roller, the support mechanism can automatically press down to avoid the screw nut when it passes and quickly reset after passing without the need for additional sensors or power sources. Compared with traditional linear guide rail support methods, this significantly reduces system complexity and maintenance costs.

[0021] This invention achieves a flexible connection structure with multi-directional buffering and self-adaptive capabilities between the hydraulic cylinder piston rod and the support wheel assembly by using a special arrangement of staggered outward-protruding elastic rods, inward-concave elastic rods, and hollow elastic rods with elliptical cross-sections in the connecting part. This structure can not only absorb the instantaneous impact load generated when the fixed plate forcibly presses down on the support wheel assembly, protecting the internal hydraulic components, but also provide floating compensation through elastic deformation when there is a slight radial runout during the high-speed rotation of the ball screw or when there are minor installation errors, ensuring that the support wheel always flexibly fits the screw, avoiding wear or jamming caused by rigid contact. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the support mechanism for a large-span ball screw provided in an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram showing the connection between the base frame, support shaft, and roller of the present invention.

[0025] Figure 3 This is a schematic diagram showing the connection between the substrate and the base frame of the present invention.

[0026] Figure 4 This is a cross-sectional view of the housing of the present invention.

[0027] Figure 5 This is a cross-sectional view of the elastic rod of the present invention.

[0028] Figure 6 This is an exploded view of the convex elastic rod, concave elastic rod, and elastic rod of the present invention.

[0029] Figure 7 This is a schematic diagram showing the connection between the convex elastic rod, the concave elastic rod, and the elastic rod of the present invention.

[0030] Explanation of reference numerals in the attached figures: 1. Base frame, 2. Support shaft, 3. Roller, 4. Base sleeve, 5. Fixing plate, 6. Hydraulic cylinder assembly, 7. Housing, 8. Piston, 9. Base plate, 10. Outwardly protruding spring rod, 11. Inwardly concave spring rod, 12. Elastic rod. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention provides a support mechanism for a large-span ball screw, such as... Figures 1 to 7 As shown.

[0033] Example 1: A support mechanism for a large-span ball screw includes a support wheel assembly for directly supporting the screw and a pressing part mounted on the screw nut. The main structure of the support wheel assembly is a base frame 1, which is designed as a rectangular frame structure with an opening on the upper side, positioned below the large-span ball screw. Its upper side has a groove adapted to the outer diameter of the ball screw to ensure no interference with the screw during support, allowing the screw portion to sink into the frame. Support shafts 2 are rotatably mounted in the internal spaces at both ends of the base frame 1, with the axes of the two support shafts 2 parallel to the axis of the ball screw. This parallel arrangement ensures that when the support mechanism is lifted upwards, the outer cylindrical surfaces of the two support shafts 2 can accurately make tangential contact with the lower surface of the ball screw. At this time, the support shafts 2 roll as the ball screw rotates, thereby counteracting the deflection deformation caused by the screw's own weight while avoiding resistance and heat from sliding friction, achieving low-friction precision support for the long screw.

[0034] To enable the support mechanism to automatically retract as the lead screw nut passes, guide portions are provided on both end faces of the base frame 1. These guide portions are specifically manifested as two rollers 3 rotatably mounted at both ends. The corresponding pressing portion includes a base sleeve 4 fixedly mounted on the lead screw nut (i.e., the moving part outside the lead screw). Fixing plates 5 are fixedly mounted on both sides of the base sleeve 4. The positions of these two fixing plates 5 spatially correspond to the rollers 3 on the end faces of the base frame 1.

[0035] The lower sides of the fixed plate 5 are designed with upward-sloping inclined surfaces at both ends, forming a wedge-shaped guide surface. When the machine tool moves the lead screw nut along the lead screw axis and approaches the support mechanism, the inclined surface at the bottom of the fixed plate 5 will first contact the roller 3 on the base frame 1. As the nut continues to feed, the wedge effect of the inclined surface converts the horizontal moving force into a vertical downward component, forcing the roller 3 to drive the entire base frame 1 and support shaft 2 downward. This process smoothly overcomes the support force below, allowing the support wheel assembly to temporarily lower and make way for the lead screw nut to pass smoothly. After the nut has completely passed, the fixed plate 5 disengages from the roller 3, and the support mechanism resets under the action of the downward force, continuing to support the lead screw.

[0036] Example 2: This embodiment details the specific structure and collaborative working principle of the power drive and energy storage regulation system in the large-span ball screw support mechanism.

[0037] A clamping assembly is installed below the support wheel assembly. This assembly applies a clamping force to the support wheel assembly, causing it to press against the ball screw. The support wheel assembly includes a hydraulic cylinder assembly 6 and a pressure supply unit that provides the pressure source. The hydraulic cylinder assembly 6, acting as the actuator, has its cylinder body fixed to the machine tool bed, while its internal piston rod extends upwards to transmit thrust. The pressure supply unit employs a combined pneumatic-hydraulic control method, with a nitrogen accumulator as its core component, which is connected to the hydraulic cylinder assembly 6 via pipeline.

[0038] The nitrogen accumulator includes a housing 7, inside which a piston 8 is slidably mounted. This piston 8 acts as a physical separator, dividing the internal space of the housing 7 into two independent chambers: a gas storage space for storing high-pressure nitrogen and an oil storage space for storing hydraulic oil. The gas storage space is pre-charged by an external nitrogen source via a gas valve to set the base pressure; the oil storage space is directly connected to the rodless chamber of the hydraulic cylinder assembly 6 via an oil valve and a high-pressure oil pipe.

[0039] The system utilizes the "gas spring" effect created by nitrogen as a compressible medium. When the system is in a supported state, the high-pressure nitrogen in the gas storage space pushes piston 8 to compress the hydraulic oil in the oil storage space, forcing the hydraulic oil into the hydraulic cylinder assembly 6. This causes the piston rod to extend, providing a continuous and flexible upward clamping force. When the mechanical structure in Embodiment 1 forces the support mechanism to press down, the piston rod of the hydraulic cylinder assembly 6 is forced to retract, pushing the hydraulic oil back into the oil storage space of the housing 7, which in turn pushes piston 8 to compress the nitrogen in the gas storage space. This process converts the kinetic energy of the downward pressure into the internal energy of the nitrogen and stores it. Once the external force is removed, the compressed nitrogen expands rapidly, driving the oil to quickly reset the hydraulic cylinder assembly 6. This design not only eliminates the need for a complex hydraulic pump station and electrical control system, but also utilizes the compressibility of nitrogen to absorb high-frequency vibrations of the system, preventing resonance during high-speed operation.

[0040] The nitrogen accumulator can also adopt a bladder-type structure, that is, a bladder is set inside the shell 7. The bladder separates the nitrogen from the hydraulic oil and plays the role of storing nitrogen. It can absorb and release nitrogen according to the changes in system pressure, thereby realizing the storage and release of energy.

[0041] When the system is in the supported state, the high-pressure nitrogen gas pre-filled in the bladder forces the hydraulic oil into the hydraulic cylinder assembly 6, thereby causing the piston rod to extend.

[0042] Example 3: To better protect the hydraulic cylinder assembly 6 and the ball screw, a connecting part is provided between the output rod of the hydraulic cylinder assembly 6 and the support wheel assembly. The connecting part plays a crucial role in connecting the two parts. It includes a base plate 9 fixedly installed at the bottom of the support wheel assembly, and multiple protruding spring rods 10 and multiple concave spring rods 11 constructed between the base plate 9 and the end face of the hydraulic cylinder piston rod.

[0043] The two ends of the multiple protruding spring rods 10 are rigidly connected to the base plate 9 and the hydraulic cylinder piston rod, respectively, and arch outward (toward away from the axis of the hydraulic cylinder assembly 6). The two ends of the multiple concave spring rods 11 are also connected to the above two components, but are recessed inward (toward closer to the axis of the hydraulic cylinder assembly 6).

[0044] Multiple protruding elastic rods 10 and multiple concave elastic rods 11 are evenly distributed along the circumference of the piston rod of the hydraulic cylinder assembly 6, and are arranged in an alternating pattern (i.e., one protruding elastic rod 10 is adjacent to one concave elastic rod 11). An elastic rod 12 is fixedly installed in the gap between the protruding elastic rods 10 and the concave elastic rods 11. The elastic rod 12 is designed as a hollow structure with an elliptical cross-section.

[0045] Multiple protruding elastic rods 10 and multiple concave elastic rods 11 form a cage-like elastic connection structure, which creates a multi-dimensional flexible joint. When the fixed plate 5 on the lead screw nut rapidly impacts the support mechanism, causing it to descend, the instantaneous impact force is extremely large. At this moment, the protruding elastic rods 10 and concave elastic rods 11 undergo elastic buckling deformation, simultaneously compressing the intermediate elastic rod 12. Since the elastic rod 12 is elliptical and hollow, it undergoes flattening deformation under pressure, absorbing a large amount of impact energy, thereby protecting the hydraulic cylinder seals below from hydraulic shock damage.

[0046] Furthermore, after the lead screw nut passes the support wheel assembly, the support wheel assembly rises and re-engages with the ball screw. At this time, the outer protruding spring rod 10 and the inner concave spring rod 11 will play a buffering role, relieving the instantaneous impact force of the ball screw on the lead screw nut and protecting the lead screw nut.

[0047] During the elastic deformation of the protruding elastic rod 10 and the multiple concave elastic rods 11, the contact points with the elastic rod 12 will move away from each other or move closer to each other. At this time, the elastic rod 12 will play a linkage role with the protruding elastic rod 10 and the multiple concave elastic rods 11, thereby increasing the supporting force of the protruding elastic rod 10 and the multiple concave elastic rods 11 and providing stable support. Furthermore, during the process of the concave spring rod 11 being subjected to a clamping force, multiple concave spring rods 11 will contract towards the center, thereby clamping against each other and avoiding excessive deformation.

[0048] Furthermore, when the ball screw itself has manufacturing errors, misalignment during installation, or radial runout due to high-speed rotation, the base plate 9 will tilt or wobble slightly. The composite structure consisting of the convex spring rod 10, the concave spring rod 11, and the elastic rod 12 allows the base plate 9 to float slightly in all directions relative to the piston rod, ensuring that the upper support wheel can always automatically align and closely fit the screw surface. This effectively prevents wear or jamming of the screw surface caused by rigid connections, greatly improving the system's adaptability and service life.

[0049] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A support mechanism for a large-span ball screw, characterized in that, include: A support wheel assembly, which is tangent to the ball screw; A clamping assembly, which is installed below the support wheel assembly, is used to apply a clamping force to the support wheel assembly to clamp the ball screw; The pressing part is installed on the screw nut threaded onto the ball screw; When the lead screw nut passes over the support wheel assembly, the downward pressure part applies downward pressure to the support wheel assembly, causing the support wheel assembly to move aside.

2. The support mechanism for a large-span ball screw as described in claim 1, characterized in that, The support wheel assembly includes: The base frame (1) is a rectangular frame with an opening on the upper side, and the base frame (1) is located below the ball screw; Two support shafts (2) are rotatably installed inside the two ends of the base frame (1), and the axis of the support shaft (2) is parallel to the axis of the ball screw, and the two support shafts (2) are tangent to the ball screw; The guide portion is installed on both ends of the base frame (1) and is adapted to the pressing portion.

3. The support mechanism for a large-span ball screw as described in claim 2, characterized in that, The guide section includes: Two rollers (3) are rotatably mounted on the two end faces of the base frame (1).

4. The support mechanism for a large-span ball screw as described in claim 3, characterized in that, The pressing part includes: Base sleeve (4), the base sleeve (4) is fixedly installed on the outside of the lead screw nut; Two fixing plates (5) are fixedly installed on both sides of the base sleeve (4). When the lead screw nut passes over the support wheel assembly, the fixing plates (5) apply a downward clamping force to the roller (3).

5. The support mechanism for a large-span ball screw as described in claim 4, characterized in that, The lower side of the fixing plate (5) is designed with upward inclined slopes at both ends.

6. The support mechanism for a large-span ball screw as described in claim 2, characterized in that, The upper side of the base frame (1) is provided with a groove adapted to the ball screw.

7. The support mechanism for a large-span ball screw as described in claim 1, characterized in that, The clamping component includes: The pressure supply unit is used to provide a power source; Hydraulic cylinder assembly (6), wherein the piston rod of the hydraulic cylinder assembly (6) is connected to the support wheel assembly through a connecting part; The pressure supply unit pressurizes the hydraulic oil inside the hydraulic cylinder assembly (6), thereby causing the piston rod of the hydraulic cylinder assembly (6) to extend and apply an upward clamping force to the support wheel assembly.

8. The support mechanism for a large-span ball screw as described in claim 7, characterized in that, The pressure supply unit includes: A nitrogen accumulator, one end of which is connected to a nitrogen source via a gas valve, and the other end of which is connected to a hydraulic cylinder assembly (6) via an oil valve.

9. The support mechanism for a large-span ball screw as described in claim 8, characterized in that, The nitrogen accumulator includes: The housing (7) has a piston (8) slidably mounted inside it. The piston (8) divides the internal space of the housing (7) into a gas storage space for storing nitrogen and an oil storage space for storing oil. The piston (8) slides inside the housing (7) to realize the extension and retraction of the piston rod of the hydraulic cylinder assembly (6).

10. The support mechanism for a large-span ball screw as described in claim 7, characterized in that, The connecting part includes: The base plate (9) is fixedly mounted on the support wheel assembly; Multiple protruding spring rods (10) are provided, with their two ends fixedly connected to the base plate (9) and the piston rod of the hydraulic cylinder assembly (6), respectively. Multiple concave spring rods (11), the two ends of the multiple concave spring rods (11) are respectively fixedly connected to the base plate (9) and the piston rod of the hydraulic cylinder assembly (6); Among them, multiple convex elastic rods (10) and multiple concave elastic rods (11) are evenly distributed along the circumference of the piston rod of the hydraulic cylinder assembly (6), and the multiple convex elastic rods (10) and multiple concave elastic rods (11) are staggered. An elastic rod (12) is fixedly installed between the convex elastic rods (10) and the concave elastic rods (11). The cross-section of the elastic rod (12) is elliptical, and the elastic rod (12) is designed as a hollow structure.

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