Electric spindle and processing equipment
By using the design of combining CFRP components and metal support shafts in the electric spindle, the vibration and thermal expansion problems of the metal spindle during ultra-high speed operation are solved, and better dynamic performance and accuracy are achieved.
Patent Information
- Application Number
- CN201910621640.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-07-10
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2039-07-10
AI Technical Summary
The existing metal spindles are used to operate at ultra-high speed due to their large weight, high thermal expansion coefficient and poor dynamic performance, resulting in poor vibration and dynamic performance, which limits their application in the field of ultra-high speed machining.
The electric spindle design is adopted that combines a CFRP member and a metal support shaft. The CFRP member is fixed to the support shaft, reducing the weight of the spindle, and providing support with axial and radial static bearings, reducing vibration and thermal expansion, and improving dynamic performance.
It realizes reducing vibration and thermal expansion during ultra-high speed operation, maintaining good dynamic performance, reducing spindle weight, and improving machining accuracy and stability.
Smart Images
Figure CN110385447B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of precision machining, and in particular to an electric spindle and machining equipment using the electric spindle. Background Art
[0002] Ultra-high-speed machining generally refers to machining processes with cutting speeds higher than 150m / s. It is an essential key technology for the development of advanced technologies such as modern materials technology, mechanical technology, optical technology, and electronic information technology. Ultra-high-speed motors are one of the cores for achieving ultra-high-speed machining. As a two-in-one product of motor and spindle, electric spindles can simplify the structure of machine tools, reduce the size of machine tools, and achieve higher motor speeds and energy conversion rates. However, extremely high speeds also place higher demands on the strength and dynamic performance of the spindle. At present, conventional spindles are heavy metal spindles, which will produce greater vibrations when running at ultra-high speeds. In addition, metal spindles have a high thermal expansion coefficient, and dynamic performance such as dynamic stiffness, dynamic balance, and vibration mode will gradually deteriorate with the increase in speed. The above defects restrict the application of electric spindles in the field of ultra-high-speed machining. Summary of the invention
[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, one object of the present invention is to provide an electric spindle that can reduce the weight of the spindle and reduce vibration during ultra-high-speed operation compared to a metal spindle, and at the same time has a lower thermal expansion coefficient and can maintain good dynamic performance during ultra-high-speed operation.
[0004] The second object of the present invention is to provide a processing equipment that can reduce the weight of the spindle and reduce vibration during ultra-high-speed operation compared to processing equipment using a metal spindle. At the same time, it has a lower thermal expansion coefficient and can maintain better dynamic performance during ultra-high-speed operation.
[0005] The technical solution adopted by the present invention is:
[0006] In a first aspect, an electric spindle is provided, comprising:
[0007] case;
[0008] A main shaft is rotatably connected to the housing, and the main shaft includes a support shaft and a CFRP component fixedly connected to the support shaft;
[0009] The motor is fixedly connected to the housing, and the output end of the motor is fixedly connected to the main shaft.
[0010] Further, the CFRP component is fixedly connected to the outer side of the support shaft, at least partially covering the outer surface of the support shaft;
[0011] Alternatively, a first through hole is axially provided inside the support shaft, and the CFRP component is fixedly connected in the first through hole to at least partially cover the inner surface of the support shaft.
[0012] Alternatively, a second through hole is axially provided inside the support shaft, and CFRP components are fixedly connected to the outside of the support shaft and the inside of the second through hole, and the CFRP component located on the outside of the support shaft at least partially covers the outer surface of the support shaft, and the CFRP component located inside the second through hole at least partially covers the inner surface of the support shaft.
[0013] Furthermore, the CFRP member is a sleeve coaxial with the support shaft.
[0014] Furthermore, the material model of the CFRP component is T700 or T800.
[0015] Furthermore, it also includes a CFRP sleeve, which is fixedly connected to the outer side of the output end.
[0016] Furthermore, it also includes an axial static pressure bearing. The main shaft is provided with a first protrusion extending in the radial direction. The axial static pressure bearing is fixedly connected to the housing and abuts against the radial side surface of the first protrusion.
[0017] Furthermore, it also includes at least two radial static pressure bearings, which are fixedly connected to the housing and distributed along the axial direction of the main shaft, and the radial static pressure bearings abut against the outer surface of the main shaft.
[0018] Furthermore, a first plug-in section is provided on the main shaft, a second protrusion is provided on the outer surface of the first plug-in section, a third through hole is provided on the output end along the axial direction of the main shaft, and the first plug-in section is plugged into the third through hole.
[0019] Furthermore, it also includes a nut, an external threaded sleeve extending along the axial direction of the main shaft is fixedly connected to the output end, a groove extending along the axial direction is provided on the wall of the external threaded sleeve, a second plug-in section with a taper is provided on the main shaft, and the nut is threadedly connected to the external threaded sleeve to fix the second plug-in section plugged into the external threaded sleeve;
[0020] In a second aspect, the present invention provides a processing device, comprising the above-mentioned electric spindle.
[0021] Beneficial effects of the present invention:
[0022] One solution of the present invention fixes a CFRP component on a support shaft, so that the electric spindle of this solution can reduce weight and reduce vibration during ultra-high-speed operation compared to an electric spindle using a metal spindle. At the same time, it has a lower thermal expansion coefficient and can maintain better dynamic performance during ultra-high-speed operation. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1is a cross-sectional view of a first embodiment of the present invention;
[0024] Figure 2 is an axial schematic diagram of a first embodiment of the present invention;
[0025] Figure 3 is a perspective schematic diagram of a first embodiment of the connection between the sleeve and the rotor;
[0026] Figure 4 It is a perspective schematic diagram of a second embodiment in which a sleeve is connected to a rotor. DETAILED DESCRIPTION
[0027] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that each technical feature and the overall technical solution of the present invention can be understood intuitively and figuratively, but it cannot be understood as a limitation on the scope of protection of the present invention.
[0028] In the description of the present invention, if it involves a description of orientation, for example, the orientation or position relationship indicated by "upper", "lower", "front", "back", "left", "right", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply 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 a limitation of the present invention. If a feature is referred to as being "set", "fixed", or "connected" to another feature, it may be directly set, fixed, or connected to the other feature, or it may be indirectly set, fixed, or connected to the other feature.
[0029] In the description of the present invention, if "several" is involved, it means one or more, if "multiple" is involved, it means more than two, if "greater than", "less than" or "exceed" is involved, it should be understood as not including the number itself, if "above", "below" or "within" is involved, it should be understood as including the number itself. If "first" or "second" is involved, it should be understood as being used to distinguish technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0030] In addition, unless otherwise defined, the technical terms and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art. The terms used in the present invention are only for describing specific embodiments, not for limiting the present invention.
[0031] Reference Figure 1 and Figure 2, respectively showing a cross-sectional view and a schematic diagram of the shaft side of the first embodiment of the present invention. As shown in the figure, the electric spindle includes a housing 1, a spindle 2, a motor 3, an axial static pressure bearing 4, a radial static pressure bearing 5 and a radial static pressure bearing 6. The electric spindle is cylindrical in shape, and the motor 3 is installed at the tail end of the electric spindle (the head end referred to in this article is Figure 1 The upper end of Figure 1 The lower end of the spindle 2 is fixedly connected to the output end of the motor 3, and the head end extends from the housing 1 to connect an external tool. The spindle 2 is rotatably connected to the housing 1 through an axial static pressure bearing 4, a radial static pressure bearing 5, and a radial static pressure bearing 6. The axial static pressure bearing 4, the radial static pressure bearing 5, and the radial static pressure bearing 6 can provide axial and radial support for the spindle 2 and realize ultra-high-speed stable rotation of the spindle 2.
[0032] In this embodiment, the housing 1 includes a cylindrical body shell 11, a flow channel shell 12, a front cover 13, a rear cover 14, a front sleeve 15, a middle sleeve 16 and a rear sleeve 17. The head end of the axial static pressure bearing 4 has a flat surface, and the tail end has a stepped surface. The head end of the body shell 11 abuts against and is connected to the stepped surface of the tail end of the axial static pressure bearing 4, the front cover 13 abuts against and is connected to the flat surface of the head end of the axial static pressure bearing 4, and the rear cover 14 is connected to the tail end of the body shell 11, thereby surrounding and forming a cavity for installing the main shaft 2 and the motor 3.
[0033] The flow channel housing 12 is sleeved on the inner side of the body housing 11, and is respectively attached to and connected with the outer side walls of the radial static pressure bearing 5 and the radial static pressure bearing 6. The front sleeve 15, the middle sleeve 16 and the rear sleeve 17 are all sleeved on the inner side of the flow channel housing 12, and the front and rear ends of the front sleeve 15 are respectively abutted against the rear end of the radial static pressure bearing 5 and the front end of the radial static pressure bearing 6, the front and rear ends of the middle sleeve 16 are respectively abutted against the rear end of the radial static pressure bearing 6 and the front end of the motor 3, and the front and rear ends of the rear sleeve 17 are respectively abutted against the rear end of the motor 3 and the rear end cover 14, thereby fixing the radial static pressure bearing 5, the radial static pressure bearing 6 and the motor 3 respectively.
[0034] In order to supply pressure liquid to the axial static pressure bearing 4, the radial static pressure bearing 5 and the radial static pressure bearing 6, an annular flow channel 131 is provided on the interface between the front end cover 13 and the axial static pressure bearing 4, and a main flow channel 121 is provided on the flow channel housing 12. The annular flow channel 131, the main flow channel 121 and the flow channel in the static pressure bearing are connected to each other. In order to achieve sealing, sealing rings are provided on both sides of the flow channel opening at the interface between the front end cover 13 and the axial static pressure bearing 4, at the interface between the flow channel housing 12 and the radial static pressure bearing 5, and at the interface between the flow channel housing 12 and the radial static pressure bearing 6.
[0035] In this embodiment, the main shaft 2 includes a coaxially arranged support shaft 21 and a sleeve 22. The support shaft 21 is made of a metal material with a small thermal expansion coefficient, such as Invar alloy, and the sleeve 22 is made of CFRP (Carbon Fiber Reinforced Polymer). The support shaft 21 has an axial first through hole inside to reduce the weight of the main shaft 2. The first end of the first through hole has an internal thread. The sleeve 22 is sleeved and fixed on the outside of the support shaft 21 and covers the entire outer wall of the support shaft 21. The first end of the sleeve 22 has a taper, which is used together with the internal thread on the support shaft 21 to fix tools such as high-speed grinding wheels. The support shaft 21 and the sleeve 22 can be fixed by bonding or other methods.
[0036] In this embodiment, the support shaft 21 is used as a skeleton, and a sleeve 22 made of CFRP is compounded on the support shaft 21. Since the density of CFRP is much lower than the density of the metal commonly used for the spindle, compared with the spindle made entirely of metal, under the same conditions of diameter, length and wall thickness, the weight of the spindle in this embodiment will be less than that of the metal spindle, that is, the rotational inertia of the spindle will be reduced, thereby ensuring that the spindle responds quickly in high-speed processing and the control accuracy in high-speed processing is ensured. The greater the proportion of CFRP material, the more obvious the weight reduction of the spindle 2. In this embodiment, the support shaft 21 is a thin-walled tube, and the wall thickness of the sleeve 22 is significantly greater than the wall thickness of the support shaft 21, that is, the main structure of the spindle 2 is the sleeve 22 made of CFRP, so the weight can be greatly reduced compared with the metal spindle, and the mechanical strength of the CFRP material is high, and the composite with the support shaft 21 can make up for the strength loss caused by the thinning of the support shaft 21. At the same time, CFRP itself has good shock absorption performance, so it can reduce the vibration generated when the spindle rotates at high speed to a certain extent. In addition, CFRP has a small thermal expansion coefficient, so that the main shaft 2 will not produce excessive expansion and deformation due to rotational heat, and can maintain good dynamic performance even during ultra-high-speed operation.
[0037] The sleeve 22 of this embodiment can ensure the consistency of weight at various locations on the same cross section and reduce vibration caused by weight imbalance.
[0038] The sleeve 22 of this embodiment is coated on the outside of the support shaft 21, which can reduce the difficulty of assembling the sleeve 22 and the support shaft 21; at the same time, compared with metal materials, CFRP is easier to form structures such as the first protrusion 221 and the first plug-in section 222 on the main structure; in addition, the external placement of the sleeve 22 can also reduce the diameter of the support shaft 21, further reducing the weight of the main shaft 2.
[0039] In this embodiment, the optional model of CFRP is T700 or T800, and the adhesive layer between the carbon fibers is epoxy resin. In this embodiment, the axial static pressure bearing 4 is close to the head end of the main shaft 2, and is used to provide axial support to the main shaft 2. An axial first protrusion 221 extends from the sleeve 22, and the first protrusion 221 is inserted into the groove on the axial static pressure bearing 4. The radially extending side surface of the first protrusion 221 serves as the axial support surface of the axial static pressure bearing 4. The radial static pressure bearing 5 is close to the head end of the main shaft 2, and the radial static pressure bearing 6 is located in the middle section of the main shaft 2. The two are used to provide radial support to the main shaft 2. To achieve the above purpose, the radial static pressure bearing 5 and the radial static pressure bearing 6 are both against the outer side wall of the sleeve 22, that is, the outer side wall of the sleeve 22 serves as the radial support surface of the radial static pressure bearing 5 and the radial static pressure bearing 6. In this embodiment, a static pressure bearing with high rotation accuracy is used to support the main shaft 2, so as to further reduce the vibration of the main shaft 2 when it rotates.
[0040] The motor 3 in this embodiment adopts a permanent magnet synchronous motor, which includes a stator 31, a coil winding 32, a rotor 33, a permanent magnet 34 and a CFRP sleeve 35. The coil winding 32 is wound on the stator 31, and the permanent magnet 34 is fixed on the rotor 33 as the output end of the motor 3. The shape, material and connection relationship of the stator 31, the coil winding 32, the rotor 33 and the permanent magnet 34 can all adopt the same technology, which will not be described in detail in this embodiment. The connection method between the main shaft 2 and the motor 3 is shown in FIG. Figure 3 The tail end of the sleeve 22 has a first plug-in section 222, and the outer contour of the cross section of the first plug-in section 222 is similar to a regular polygon, that is, it can be regarded as that a plurality of second protrusions 223 are provided on the outer surface of the first plug-in section 222. The interior of the rotor 33 has an axial third through hole, and the cross-sectional shape of the third through hole is the same as that of the first plug-in section 222. The first plug-in section 222 is plugged into the third through hole and bonded and fixed, thereby realizing the connection between the main shaft 2 and the motor 3. Compared with a main shaft with a circular cross-section, this embodiment can avoid relative sliding between the sleeve 22 and the rotor 33 during high-speed rotation, thereby enabling the electric spindle to reach a higher speed.
[0041] Since the rotor 33 also needs to rotate at ultra-high speed, a CFRP sleeve 35 is fixedly connected to the outside of the rotor 33. The CFRP sleeve 35 can fix the permanent magnet 34 to prevent the permanent magnet 34 from being peeled off due to centrifugal force during high-speed operation. At the same time, the low density and high strength of the CFRP material are used to reduce the inertia of the motor output end.
[0042] Based on the first embodiment, the present invention also discloses other alternative embodiments, such as:
[0043] Second embodiment
[0044] The difference between this embodiment and the first embodiment is that the sleeve 22 is located inside the support shaft 21 and is fitted and fixed to the inner wall of the support shaft 21. Accordingly, the first protrusion 221, the first plug section 222, the second protrusion 223 and other structures are adjusted to the support shaft 21.
[0045] Third embodiment
[0046] The difference between this embodiment and the first embodiment is that a second axial through hole is provided on the support shaft 21 , and a sleeve 22 is fixedly connected to the outer side of the support shaft 21 and the inside of the second through hole.
[0047] Fourth embodiment
[0048] The difference between this embodiment and the first embodiment is that the length of the sleeve 22 is shorter than the length of the support shaft 21, that is, the sleeve 22 does not completely cover the outer wall of the support shaft 21. In this case, the axial connection position of the sleeve 22 on the support shaft 21 is not limited.
[0049] Fifth embodiment
[0050] The difference between this embodiment and the first embodiment is that a groove is provided on the outer side wall of the support shaft, and part or all of the sleeve 22 is embedded in the groove.
[0051] Sixth embodiment
[0052] The difference between this embodiment and the first embodiment is that the CFRP component is not a complete component, but includes multiple components, such as a plurality of rings distributed along the radial direction of the support shaft 21, or a plurality of arc-shaped sheets distributed along the circumferential direction of the support shaft 21.
[0053] Seventh embodiment
[0054] The difference between this embodiment and the first embodiment is that part or all of the body shell 11, flow channel shell 12, front end cover 13, rear end cover 14, front end sleeve 15, middle sleeve 16 and rear end sleeve 17 constituting the shell 1 can be formed into one component, for example, the body shell 11 and the flow channel shell 12 are formed into one component, the body shell 11 and the rear end cover 14 are formed into one component, etc.
[0055] Eighth embodiment
[0056] The difference between this embodiment and the first embodiment is that, when the precision requirement is not high, the permanent magnet synchronous motor can be replaced by an asynchronous motor, and the hydrostatic bearing can be replaced by a ball bearing.
[0057] Ninth embodiment
[0058] Reference Figure 4The difference between this embodiment and the first embodiment is that the end of the rotor 33 is fixedly connected with an external threaded sleeve 331 extending along the axial direction of the main shaft 2, and a groove 332 extending along the axial direction is provided on the wall of the external threaded sleeve 331, and a second plug-in section with a taper (not shown in the figure) is provided on the sleeve 22. When the second plug-in section is plugged into the external threaded sleeve 331, the threaded connection between the nut 7 and the external threaded sleeve 331 causes the external threaded sleeve 331 to shrink inward and clamp the second plug-in section. This connection method can use the taper of the second plug-in section to achieve the centering of the main shaft 2.
[0059] The invention also discloses a processing device, which applies the electric spindle in the above embodiments.
[0060] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalent modifications or substitutions are all included in the scope defined by the claims of this application. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.
Claims
1. An electric spindle, characterized in that: include: case; A main shaft, rotatably connected to the housing, the main shaft comprising a support shaft and a CFRP member fixedly connected to the support shaft; A motor, fixedly connected to the housing, wherein an output end of the motor is fixedly connected to the main shaft; It also includes an axial static pressure bearing, wherein the main shaft is provided with a first protrusion extending in the radial direction, and the axial static pressure bearing is fixedly connected to the housing and abuts against the radial side surface of the first protrusion; It also includes at least two radial static pressure bearings, which are fixedly connected to the housing and distributed along the axial direction of the main shaft, and the radial static pressure bearings abut against the outer surface of the main shaft; The main shaft is rotatably connected to the housing through the axial static pressure bearing and the radial static pressure bearing; The housing comprises a body shell, a flow channel shell, a front end cover and a rear end cover, the head end of the axial static pressure bearing has a flat surface, and the tail end has a stepped surface, the head end of the body shell abuts against and is connected to the stepped surface of the tail end of the axial static pressure bearing, the front end cover abuts against and is connected to the flat surface of the head end of the axial static pressure bearing, and the rear end cover is connected to the tail end of the body shell, thereby surrounding and forming a cavity for installing the main shaft and the motor; The flow channel housing is sleeved on the inner side of the body housing and is respectively attached to and connected with the outer side walls of each radial static pressure bearing. An annular flow channel is provided on the interface between the front end cover and the axial static pressure bearing. A main flow channel is provided on the flow channel housing. The annular flow channel, the main flow channel and the flow channels in each radial static pressure bearing and the axial static pressure bearing are interconnected. The main shaft is provided with a first plug-in section, the outer surface of the first plug-in section is provided with a second protrusion, the output end is provided with a third through hole along the axial direction of the main shaft, and the first plug-in section is plugged into the third through hole; It also includes a nut, and the output end is fixedly connected to an externally threaded sleeve extending along the axial direction of the main shaft, the barrel wall of the externally threaded sleeve is provided with a groove extending along the axial direction, and the main shaft is provided with a second plug-in section with a taper, and the nut is threadedly connected to the externally threaded sleeve to fix the second plug-in section inserted in the externally threaded sleeve.
2. The electric spindle according to claim 1, characterized in that: The CFRP component is fixedly connected to the outer side of the support shaft, and at least partially covers the outer surface of the support shaft; Alternatively, a first through hole is provided inside the support shaft along the axial direction, and the CFRP component is fixedly connected in the first through hole to at least partially cover the inner surface of the support shaft; Alternatively, a second through hole is axially provided inside the support shaft, and the CFRP component is fixedly connected to the outside of the support shaft and the inside of the second through hole, and the CFRP component located on the outside of the support shaft at least partially covers the outer surface of the support shaft, and the CFRP component located inside the second through hole at least partially covers the inner surface of the support shaft.
3. The electric spindle according to claim 2, characterized in that: The CFRP member is a sleeve coaxial with the support shaft.
4. The electric spindle according to claim 1, characterized in that: The material model of the CFRP component is T700 or T800.
5. The electric spindle according to claim 1, characterized in that: It also includes a CFRP sleeve, which is fixedly connected to the outer side of the output end.
6. A processing equipment, characterized in that: The invention comprises the electric spindle according to any one of claims 1 to 5.