Planetary lead screw internal thread superfinishing hard turning equipment

Abstract

A planetary lead screw internal thread superfinishing hard turning device comprises a base, a main shaft, a tool rest, an online contour detection mechanism and a damping mechanism are installed on the base, and the online contour detection mechanism is arranged on the axis of the main shaft and can conduct online contour scanning on parts on the main shaft and conduct real-time feedback to achieve machining amount correction. The tool rest is connected to the base through a driving mechanism capable of adjusting the position of the tool rest, the driving mechanism comprises a first driving mechanism body driving the tool rest to move, the first driving mechanism body is installed on an X-direction hydrostatic guide rail, and the X-direction hydrostatic guide rail is installed on a second driving mechanism body. The second driving mechanism is installed on the Z-direction hydrostatic pressure guide rail, and the first driving mechanism and the second driving mechanism are both moving magnet type linear motors. The machining precision and stability of the machine tool are greatly improved, the walking stability of the driving mechanism is improved, the movement precision is improved, and online contour detection and correction can be conducted.

Description

Technical Field

[0001] The invention belongs to the technical field of hard turning machine tools, and in particular relates to ultra-precision hard turning equipment for the internal threads of planetary screws. Background Art

[0002] For machining high-hardness materials with internal threads of planetary screws (hardness HRC ≥ 65), the industry's most common machining process involves heat treating the screw nut to the required hardness, then rough-milling the part using whirling milling. A second common machining process involves rough-machining the part before heat treatment using a whirling mill or lathe. The part is then heat treated, quenched to the required hardness, and then super-finished on a grinder. Rapid advancements in CBN tooling technology have enabled super-finish turning of high-hardness materials, making it increasingly possible to replace super-finish grinding with super-finish turning.

[0003] In the existing technology, ultra-precision hard turning refers to the process method of ultra-precision machining the internal threads of planetary screws made of hardened steel as the final processing. Hard turning machines can realize the turning of planetary screw internal thread parts with complex tooth shapes, but some existing hard turning machines basically use practical roller linear guides. High-speed machining movement will produce pitch and yaw, which cannot meet the requirements of high-precision turning. Some other machines realize high-speed movement through ball screws, and the movement accuracy and high-speed walking conditions are not ideal, which also affects the processing effect of planetary screw internal threads. In addition, there is no raceway surface detection in China. At present, only the linear and cylindrical dimensions of the parts are detected. The internal threads in the planetary screw pair cannot be accurately scanned online, and the surface contour coordinate point cloud data model of the parts is measured for comparison and remanufacturing compensation. Therefore, it is necessary to design planetary screw internal thread ultra-precision hard turning equipment. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology, the present invention proposes a planetary screw internal thread ultra-precision hard turning equipment, which greatly improves the processing accuracy and stability of the machine tool, improves the static stiffness, dynamic stiffness, thermal stability, and vibration resistance of the machine tool, increases the walking stability of the drive mechanism, improves the motion accuracy, and can perform contour detection and correction online.

[0005] The technical solution adopted in the present invention is:

[0006] Planetary screw internal thread ultra-precision hard turning equipment includes a base, on which a spindle, a tool holder, an online contour detection mechanism, and a shock-absorbing mechanism are installed. The online contour detection mechanism is arranged on the axis of the spindle and can perform online contour scanning of parts on the spindle and provide real-time feedback to achieve processing amount correction. The tool holder is connected to the base through a drive mechanism that can adjust its position. The drive mechanism includes a first drive mechanism that drives the tool holder to move. The first drive mechanism is installed on an X-axis liquid hydrostatic guide rail, and the X-axis liquid hydrostatic guide rail is installed on a second drive mechanism. The second drive mechanism is installed on a Z-axis liquid hydrostatic guide rail. The first drive mechanism and the second drive mechanism both use moving magnet linear motors.

[0007] Furthermore, both inner side walls of the X-direction liquid hydrostatic guide rail and the Z-direction liquid hydrostatic guide rail are provided with oil chamber slider grooves, and sliders are slidably connected in the oil chamber slider grooves. The slider in the X-direction liquid hydrostatic guide rail is fixedly connected to the support plate of the tool holder, and the slider in the Z-direction liquid hydrostatic guide rail is fixedly connected to the bottom surface of the X-direction liquid hydrostatic guide rail.

[0008] Furthermore, the sliders are all pushed by the electromagnetic thrust generated by the corresponding moving magnet linear motors to move in a linear direction.

[0009] Furthermore, the shock absorbing mechanism is two integrated shock absorbing mechanisms, which are respectively arranged on both sides of the base.

[0010] Furthermore, the shock absorbing mechanism adopts an air-floating shock absorber.

[0011] Furthermore, the main shaft is installed on the base through a main shaft seat.

[0012] Furthermore, the base and the spindle seat are both made of marble.

[0013] Furthermore, the online contour detection mechanism is fixedly connected to the base through bolts and nuts and the linear guide rail.

[0014] Furthermore, the detection steps of the online contour detection mechanism are as follows:

[0015] S1, scan the surface profile of the internal thread of the planetary screw to measure the surface profile size and surface micro profile of the part;

[0016] S2, compare the actual value obtained with the corresponding set value one by one to make a qualified judgment;

[0017] If the process is qualified in step S3, the process ends; if the process is unqualified, the process proceeds to step S4.

[0018] S4, perform correction processing according to the corresponding parameter difference.

[0019] Furthermore, the surface micro-profile in step S1 includes surface profile, surface waviness and surface roughness.

[0020] Beneficial effects of the present invention:

[0021] 1. Both the first drive mechanism and the second drive mechanism of the present invention adopt a moving magnet linear motor, which greatly simplifies the structure, greatly reduces the weight and volume, reduces the motion inertia, improves the dynamic response performance and positioning accuracy, and is easy to magnetically levitate, so that there is always a certain air gap between the slider and the stator without contact, eliminating contact friction resistance, greatly improving the sensitivity, speed and servo performance of the system, and the mechanical friction loss is almost zero, the failure rate is low, maintenance-free, safe and reliable operation, and long service life.

[0022] 2. The present invention is equipped with an online contour detection mechanism, which can provide real-time detection feedback and adjust and correct processing, thereby improving processing quality. The online contour detection mechanism can be installed movably to fully consider the processing capacity range of the processing machine tool and is suitable for different specifications and series of raceway detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 Schematic diagram of the structure of the driving mechanism of the present invention.

[0025] In the figure: 1. Base; 2. Spindle; 3. Tool holder; 4. Online contour detection mechanism; 5. Shock absorption mechanism; 6. X-axis hydrostatic guide; 7. Z-axis hydrostatic guide; 8. Moving magnet linear motor; 9. Oil chamber slider groove; 10. Slider; 11. Spindle seat; 12. Nitrogen balance cylinder. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more, unless otherwise clearly defined.

[0028] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0029] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0030] See also Figure 1 、 Figure 2, this embodiment provides a planetary screw internal thread super-precision hard turning equipment, including a base 1, on which are mounted a spindle 2, a tool holder 3, an online contour detection mechanism 4, and a shock-absorbing mechanism 5. The online contour detection mechanism 4 is arranged on the axis of the spindle 2 and can perform online contour scanning of the parts on the spindle 2 and provide real-time feedback to achieve processing amount correction. The tool holder 3 is connected to the base 1 through a driving mechanism that can adjust its position. The driving mechanism includes a first driving mechanism that drives the tool holder 3 to move. The first driving mechanism is mounted on an X-axis liquid hydrostatic guide rail 6, and the X-axis liquid hydrostatic guide rail 6 is mounted on a second driving mechanism. The second driving mechanism is mounted on a Z-axis liquid hydrostatic guide rail 7. The first driving mechanism and the second driving mechanism both adopt a moving magnet linear motor 8.

[0031] In this embodiment, both the X-axis and Z-axis hydrostatic guide rails 6 and 7 are provided with oil chamber slider grooves 9 on their inner sidewalls. Sliders 10 are slidably connected within these oil chamber slider grooves 9. The sliders within the X-axis hydrostatic guide rail 6 are fixedly connected to the support plate of the tool holder 3, while the sliders within the Z-axis hydrostatic guide rail 7 are fixedly connected to the bottom surface of the X-axis hydrostatic guide rail 6. Each slider 10 is driven by the electromagnetic thrust generated by the corresponding moving magnet linear motor 8, thereby moving in a linear direction. When the second drive mechanism is activated, the motor's moving magnets move at high speed, generating a magnetic field on the lower magnetic plate. The slider connected to the X-axis hydrostatic guide rail 6 actuates, thereby driving the X-axis hydrostatic guide rail 6 in linear motion in the Z direction, and in turn, the tool holder 3 in linear motion in the Z direction. When the first drive mechanism is activated, the motor's moving magnets move at high speed, generating a magnetic field on the lower magnetic plate. The slider connected to the tool holder 3 actuates, thereby driving the tool holder 3 in linear motion in the X direction. The oil chamber chute cross-sections of both the X-axis hydrostatic guide 6 and the Z-axis hydrostatic guide 7 are linear, flat structures. This linear, flat guide rail structure increases horizontal and vertical rigidity, enhancing the guide rail's anti-overturning capability and achieving higher motion precision. A nitrogen balancing cylinder 12 is installed on the X-axis hydrostatic guide 6 to balance the weight of the X-axis moving components, increasing operational smoothness and improving X-axis motion precision.

[0032] The shock absorbing mechanism 5 described in this embodiment is two integrated shock absorbing mechanisms, which are respectively arranged on both sides of the base 1. The shock absorbing mechanism 5 adopts an air-floating shock absorber. The spindle 2 is mounted on the base 1 through the spindle seat 11. The base 1 and the spindle seat 11 are both made of marble. Since marble has the advantages of non-deformation, high hardness, strong wear resistance, uniform structure, extremely small linear expansion coefficient, corrosion resistance, high temperature resistance, maintenance-free, good rigidity, stable material, high mechanical precision, rust resistance, anti-magnetic, insulation, etc., the static stiffness, dynamic stiffness, thermal stability and vibration resistance of the machine tool are improved.

[0033] The online contour detection mechanism 4 of this embodiment is fixedly connected to the base 1 through bolts and nuts and a linear guide rail. The detection steps of the online contour detection mechanism are as follows:

[0034] S1, scan the surface profile of the internal thread of the planetary screw to measure the surface profile size and surface micro-profile of the part; the surface micro-profile includes surface profile, surface waviness and surface roughness;

[0035] S2, compare the actual value obtained with the corresponding set value one by one to make a qualified judgment;

[0036] If the process is qualified in step S3, the process ends; if the process is unqualified, the process proceeds to step S4.

[0037] S4, perform correction processing according to the corresponding parameter difference.

[0038] The first drive mechanism and the second drive mechanism of the present invention both use dynamic magnetic linear motors, which greatly simplify the structure, greatly reduce the weight and volume, reduce the motion inertia, improve the dynamic response performance and positioning accuracy, and are easy to magnetically support, so that there is always a certain air gap between the slider and the stator without contact, eliminating contact friction resistance, greatly improving the sensitivity, speed and servo performance of the system, and the mechanical friction loss is almost zero, the failure rate is low, maintenance-free, safe and reliable operation, and long service life. The present invention is provided with an online contour detection mechanism that can detect feedback in real time and adjust and correct processing, thereby improving the processing qualification. The online contour detection mechanism can be movably installed to fully consider the processing capacity range of the processing machine tool to adapt to the detection of raceways of different specifications and different series.

Claims

1. Planetary screw internal thread super-precision hard turning equipment, including a base, on which a spindle, a tool holder, an online profile detection mechanism, and a shock absorption mechanism are installed, characterized by: The online contour detection mechanism is arranged on the axis of the main spindle and can perform online contour scanning of the parts on the main spindle and provide real-time feedback to realize processing amount correction. The tool holder is connected to the base through a driving mechanism that can adjust its position. The driving mechanism includes a first driving mechanism that drives the tool holder to move. The first driving mechanism is installed on the X-direction liquid hydrostatic guide rail, the X-direction liquid hydrostatic guide rail is installed on the second driving mechanism, and the second driving mechanism is installed on the Z-direction liquid hydrostatic guide rail. The first driving mechanism and the second driving mechanism both adopt moving magnet linear motors.

2. The planetary screw internal thread super-precision hard turning equipment according to claim 1, characterized in that: The inner side walls of the X-direction liquid hydrostatic guide rail and the Z-direction liquid hydrostatic guide rail are both provided with oil chamber slider grooves, and sliders are slidably connected in the oil chamber slider grooves. The slider in the X-direction liquid hydrostatic guide rail is fixedly connected to the support plate of the tool holder, and the slider in the Z-direction liquid hydrostatic guide rail is fixedly connected to the bottom surface of the X-direction liquid hydrostatic guide rail.

3. The planetary screw internal thread super-precision hard turning equipment according to claim 2, characterized in that: The sliders are all pushed by the electromagnetic thrust generated by the corresponding moving magnet linear motors to move in a linear direction.

4. The planetary screw internal thread super-precision hard turning equipment according to claim 1, characterized in that: The shock absorbing mechanism is two integrated shock absorbing mechanisms, which are respectively arranged on both sides of the base.

5. The planetary screw internal thread super-precision hard turning equipment according to claim 4, characterized in that: The shock absorbing mechanism adopts an air-floating shock absorber.

6. The planetary screw internal thread super-precision hard turning equipment according to claim 1, characterized in that: The main shaft is installed on the base through a main shaft seat.

7. The planetary screw internal thread super-precision hard turning equipment according to claim 6, characterized in that: The base and the spindle seat are both made of marble.

8. The planetary screw internal thread super-precision hard turning equipment according to claim 1, characterized in that: The online contour detection mechanism is fixedly connected to the base through bolts and nuts and a linear guide rail.

9. The planetary screw internal thread super-precision hard turning equipment according to claim 8, characterized in that: The detection steps of the online contour detection mechanism are as follows: S1, scan the surface profile of the internal thread of the planetary screw to measure the surface profile size and surface micro profile of the part; S2, compare the actual value obtained with the corresponding set value one by one to make a qualified judgment; If the process is qualified in step S3, the process ends; if the process is unqualified, the process proceeds to step S4. S4, perform correction processing according to the corresponding parameter difference.

10. The planetary screw internal thread super-precision hard turning equipment according to claim 9, characterized in that: The surface micro-profile in step S1 includes surface profile, surface waviness and surface roughness.

Images