A spindle body assembly, an air bearing electric spindle and a drilling machine

Abstract

The application discloses a main shaft body assembly, an air-floating electric main shaft and a drilling machine, which comprises a body inner sleeve and a body outer sleeve, the body inner sleeve is provided with a first axial inner hole, the body outer sleeve is provided with a second axial inner hole, the body inner sleeve is sleeved in the second axial inner hole of the body outer sleeve to form an integral structure, at least piezoelectric ceramic sheets are arranged between the body inner sleeve and the body outer sleeve at a mounting clamping position of the main shaft body assembly, the piezoelectric ceramic sheets extend from an inner surface to an outer surface along a thickness direction, the inner surface of the piezoelectric ceramic sheets is attached to the body inner sleeve, and the outer surface of the piezoelectric ceramic sheets is attached to the body outer sleeve. The piezoelectric ceramic is innovatively used to constrain the expansion amount of the body, so that the drilling precision is not influenced by the expansion of the main shaft body caused by temperature rise during high-speed machining. The technical scheme of the application greatly enhances the overall rigidity of the main shaft, avoids the influence of temperature rise on the outer diameter size of the main shaft, guarantees the perpendicularity of the main shaft core center line, and greatly improves the machining efficiency and the drilling precision.

Description

Technical Field

[0001] This invention relates to the field of drilling equipment, and in particular to a spindle body assembly, an air-bearing electric spindle, and a drilling rig. Background Technology

[0002] With economic development and technological advancements, PCB drilling machines with higher processing efficiency have been developed. The Z-axis system of these machines on the market boasts a movement acceleration exceeding 3G. After extreme optimization, the theoretical drilling rate of the Z-axis system can reach 800 holes / min. However, the problem of not being able to reduce spindle weight persists (the greater the spindle weight, the greater the inertia, and the lower the ultimate processing efficiency of the PCB drilling machine), severely reducing its processing efficiency. Furthermore, during ultra-high-speed drilling of small holes, low drilling accuracy and even drill bit breakage frequently occur. Summary of the Invention

[0003] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a spindle body assembly, an air-bearing electric spindle, and a drilling rig.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] In a first aspect, a spindle body assembly includes an inner sleeve and an outer sleeve. The inner sleeve has a first axial inner hole, and the outer sleeve has a second axial inner hole. The inner sleeve is fitted into the second axial inner hole of the outer sleeve to form an integral structure. A piezoelectric ceramic sheet is provided between the inner sleeve and the outer sleeve at least at the mounting clamping position of the spindle body assembly. The piezoelectric ceramic sheet extends from its inner surface to its outer surface along the thickness direction. The inner surface of the piezoelectric ceramic sheet is fitted with the inner sleeve, and the outer surface of the piezoelectric ceramic sheet is fitted with the outer sleeve.

[0006] In conjunction with the first aspect, in some implementations of the first aspect, the gap between the inner sleeve and the outer sleeve of the body at the location where the piezoelectric ceramic sheet is disposed is less than the thickness of the piezoelectric ceramic sheet.

[0007] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the piezoelectric ceramic sheet is in the shape of an annular sleeve, and the piezoelectric ceramic sheet is fitted between the inner sleeve and the outer sleeve of the body.

[0008] In combination with the first aspect and the above-mentioned implementation methods, in some implementation methods of the first aspect, the piezoelectric ceramic sheet is tile-shaped, and multiple piezoelectric ceramic sheets are arranged along the circumferential direction of the main spindle body assembly.

[0009] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the inner sleeve and the outer sleeve of the body are provided with pin holes at corresponding positions, and the inner sleeve and the outer sleeve of the body are fixedly connected by pins provided in the pin holes.

[0010] In combination with the first aspect and the above-mentioned implementation methods, in some implementation methods of the first aspect, the inner sleeve of the machine body is an aluminum alloy inner sleeve, the outer sleeve of the machine body is a steel outer sleeve, and the aluminum alloy inner sleeve is provided with an integrated bearing seat inside the mounting clamp position of the spindle body assembly.

[0011] In a second aspect, an air-bearing electric spindle includes a spindle core assembly and a spindle body assembly as described in any of the above implementations. The spindle core assembly is supported in a first axial inner hole within the body of the spindle body assembly via an air bearing. The spindle body assembly is provided with an electronic airflow monitoring component for monitoring the overflow airflow from the air bearing.

[0012] In conjunction with the first aspect, some implementations of the first aspect include the spindle body assembly described in some of the above implementations, wherein the bearing housing has a bearing mounting cavity inside, the bearing mounting cavity has an air bearing, the electronic airflow monitoring assembly includes an air shroud, the air shroud covers one end of the bearing mounting cavity, the air shroud has an exhaust port and a shaft hole, the spindle assembly passes through the shaft hole, and the exhaust port has an electronic airflow monitor.

[0013] In combination with the first aspect and the above-described implementations, some implementations of the first aspect further include a controller and a power supply. The piezoelectric ceramic sheet and the electronic airflow monitoring component are connected to the controller and the power supply. The controller is used to control the expansion and contraction of the piezoelectric ceramic sheet based on the airflow information collected by the electronic airflow monitoring component, so as to offset the expansion of the spindle body assembly caused by temperature.

[0014] Thirdly, a drilling rig includes an air-bearing electric spindle as described in any of the above implementations.

[0015] One of the above technical solutions has at least one of the following advantages or beneficial effects: In the technical solution of this invention, to ensure the rigidity of the spindle's outer diameter and prevent the spindle from deforming easily after the machine tool clamp locks the spindle, a machine body structure design combining an inner sleeve, a piezoelectric ceramic sheet, and an outer sleeve is adopted. Based on the principles of material mechanics, the piezoelectric ceramic sheet and the machine body are integrated at the corresponding positions of the machine tool clamping position. The innovative use of piezoelectric ceramics constrains the expansion of the machine body, preventing the spindle body's temperature rise and expansion from affecting drilling accuracy during high-speed machining. The technical solution of this invention greatly enhances the overall rigidity of the spindle, avoids the impact of temperature rise on the spindle's outer diameter, ensures the perpendicularity of the spindle's centerline, and significantly improves machining efficiency and drilling accuracy.

[0016] 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

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a schematic diagram of an embodiment of the spindle body assembly of the present invention;

[0019] Figure 2 This is a schematic diagram of an embodiment of the air-bearing electric spindle of the present invention;

[0020] Figure 3 yes Figure 2 A schematic diagram of the electronic airflow monitoring component and bearing housing structure is shown in one embodiment. Detailed Implementation

[0021] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0022] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0023] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0025] in, Figure 2 The reference direction coordinate system of this invention is given below, in conjunction with... Figure 2 The directions shown illustrate embodiments of the present invention.

[0026] The inventors of this application have discovered that during ultra-high-speed drilling of small holes, low drilling accuracy and even drill bit breakage frequently occur. One major reason for this is that the spindle body heats up and expands during machining, causing displacement of the machine tool clamping mechanism, reducing the spindle's vertical accuracy, and making it impossible to guarantee that the drill bit is perpendicular to the PCB board during high-speed drilling. In other words, to achieve optimal drilling accuracy, the rigidity of the spindle's outer cylindrical clamping mechanism must be sufficiently large and minimally affected by temperature rise; otherwise, thermal expansion can easily cause clamping displacement, thus affecting drilling accuracy.

[0027] See Figure 1 An embodiment of the present invention provides a spindle body assembly, including an inner sleeve 100 and an outer sleeve 200. The inner sleeve 100 has a first axial inner hole 101 for arranging a motor, a spindle core assembly 300, etc. The outer sleeve 200 has a second axial inner hole. The inner sleeve 100 is fitted into the second axial inner hole of the outer sleeve 200 to form an integral structure. A piezoelectric ceramic sheet 400 is provided between the inner sleeve 100 and the outer sleeve 200 at least at the mounting clamp position of the spindle body assembly. The piezoelectric ceramic sheet 400 extends from the inner surface to the outer surface along the thickness direction. The inner surface of the piezoelectric ceramic sheet 400 is in contact with the inner sleeve 100, and the outer surface of the piezoelectric ceramic sheet 400 is in contact with the outer sleeve 200. The control line of the piezoelectric ceramic sheet 400 passes through the wire hole of the inner sleeve 100, is introduced into the first axial inner hole 101, and finally leads to the end of the spindle body assembly.

[0028] During ultra-high-speed machining, the spindle body inevitably expands due to temperature rise, causing the machine tool clamp to shift and resulting in poor spindle core perpendicularity, ultimately affecting machining accuracy (hole opening, hole wall quality, hole center position, etc.). Therefore, the expansion of the machine body is controlled by applying a corresponding voltage to the piezoelectric ceramic plate 400. Specifically, based on the spindle's operating conditions, such as operating temperature, operating time, and operating speed, the expansion / contraction amount corresponding to the input voltage is applied to the piezoelectric ceramic plate 400 on the spindle body assembly. This causes the piezoelectric ceramic plate 400 to restrain the deformation of the machine body assembly in the opposite direction, thereby counteracting the expansion of the outer casing 200 caused by high temperature, ensuring spindle perpendicularity, and improving drilling accuracy.

[0029] In the technical solution of this invention, to ensure the rigidity of the spindle's outer diameter and prevent deformation after the spindle is clamped in the machine tool, a machine body structure design combining an inner sleeve 100, a piezoelectric ceramic plate 400, and an outer sleeve 200 is adopted. Based on the principles of material mechanics, the piezoelectric ceramic plate 400 and the machine body are integrated at the corresponding positions in the machine tool clamping area. This innovative use of piezoelectric ceramics constrains the expansion of the machine body, preventing the spindle's thermal expansion from affecting drilling accuracy during high-speed machining. The technical solution of this invention significantly enhances the overall rigidity of the spindle, avoids the impact of temperature rise on the spindle's outer diameter, ensures the perpendicularity of the spindle's centerline, and greatly improves machining efficiency and drilling accuracy.

[0030] In some embodiments, see Figure 1 The gap between the inner sleeve 100 and the outer sleeve 200 at the location where the piezoelectric ceramic sheet 400 is set is less than the thickness of the piezoelectric ceramic sheet 400. In other words, the piezoelectric ceramic sheet 400 is interference-fitted between the inner sleeve 100 and the outer sleeve 200, which on the one hand ensures the strength of the body components, and on the other hand greatly improves the ability of the piezoelectric ceramic sheet 400 to offset the expansion of the body components.

[0031] In some embodiments, see Figure 1 The piezoelectric ceramic sheet 400 is in the shape of an annular sleeve. The piezoelectric ceramic sheet 400 is fitted between the inner sleeve 100 and the outer sleeve 200 of the machine body. In actual processing, the spindle temperature rises and the machine body expands. Changing the voltage applied to the piezoelectric ceramic sheet 400 reduces the radial dimension of the piezoelectric ceramic itself, thereby eliminating the influence of thermal expansion in the radial direction of the machine body.

[0032] In some embodiments, the piezoelectric ceramic sheet 400 is tile-shaped, and multiple piezoelectric ceramic sheets 400 are arranged along the circumferential direction of the spindle body assembly. Each piezoelectric ceramic sheet 400 is individually or uniformly connected to a control voltage to flexibly constrain the expansion of the machine body. In actual processing, the spindle temperature rises and the machine body expands. Changing the voltage applied to the piezoelectric ceramic sheet 400 reduces the radial dimension of the piezoelectric ceramic itself, thereby eliminating the influence of thermal expansion in the radial direction of the machine body.

[0033] In some embodiments, see Figure 1 The inner sleeve 100 and the outer sleeve 200 are provided with pin holes at corresponding positions. The inner sleeve 100 and the outer sleeve 200 are fixedly connected by pins 201 set in the pin holes. The inner sleeve 100 and the outer sleeve 200 are assembled and connected by pins, which has high assembly accuracy and is convenient to connect.

[0034] In some embodiments, in order to reduce the overall weight of the machine body components and further improve processing efficiency, the inner sleeve 100 is an aluminum alloy inner sleeve 100 and the outer sleeve 200 is a steel outer sleeve 200. The combination structure of the aluminum alloy inner sleeve 100 and the steel outer sleeve 200 reduces the overall weight of the spindle and significantly improves processing efficiency.

[0035] The aluminum alloy inner sleeve 100 has an integrated bearing seat 102 located inside the mounting clamp position of the spindle body assembly. On one hand, the bearing seat 102 of the aluminum alloy inner sleeve 100, positioned inside the mounting clamp position, further increases the rigidity of the body and enhances spindle stability. On the other hand, the integrated structural design of the bearing seat 102 and the body eliminates the assembly errors inherent in treating the air-bearing spindle bearing seat 102 as a separate part, ensuring spindle perpendicularity.

[0036] See Figure 2 The embodiments of the present invention also provide an air-bearing electric spindle, including a spindle core assembly 300 and a spindle body assembly in any of the above embodiments. The spindle core assembly 300 is supported by an air bearing in the first axial inner hole 101 of the inner sleeve 100. Specifically, a pressure air film is formed between the spindle core assembly 300 and the upper air bearing 301, the lower air bearing 302, and the thrust bearing assembly 303, supporting the spindle core assembly 300 in a suspended state. The stator drives the spindle core assembly 300 to rotate at high speed. Coolant is supplied through the aluminum water jacket 500, the body assembly, and the thrust bearing assembly 303 to cool the lower air bearing assembly 302, the thrust bearing assembly 303, the upper air bearing 301, and the motor. Gas is supplied through the cylinder assembly 600 to cut the spindle core assembly 300, enabling automatic tool changing of the spindle.

[0037] The spindle body assembly is equipped with an electronic airflow monitoring component for monitoring the overflow airflow from the air bearing. This embodiment utilizes the characteristic that the centrifugal expansion of the spindle core assembly 300 after high-speed rotation causes a decrease in the gap between the air bearing and the air float position, resulting in a decrease in airflow. This characteristic serves as the control signal for the piezoelectric ceramic element 400. Specifically, the electronic airflow monitoring component installed on the body assembly feeds the collected airflow information back to the host computer. By changing the input voltage, the spindle temperature rises during actual machining, causing the body to expand. Changing the voltage applied to the piezoelectric ceramic reduces its radial dimension, thus eliminating the effect of thermal expansion in the radial direction of the body. This controls the expansion and contraction of the piezoelectric ceramic on the body assembly, thereby offsetting the expansion of the outer casing 200 due to high temperature, ensuring spindle perpendicularity, and improving drilling accuracy. This embodiment, through the use of a pneumatically controlled piezoelectric ceramic module design, satisfies the influence of body temperature rise and expansion on the spindle outer diameter under ultra-high speed machining conditions, ensuring spindle perpendicularity and improving drilling accuracy.

[0038] In some embodiments, see Figure 3 The air-bearing electric spindle includes the spindle body assembly of some of the embodiments described above. The bearing housing 102 has a bearing mounting cavity 103 inside, and an air-bearing bearing is installed in the bearing mounting cavity 103. The bearing pressure plate is locked in place by three evenly distributed locking screws. The electronic airflow monitoring assembly includes an air shroud 701, which covers one end of the bearing mounting cavity 103. The air shroud 701 has an exhaust port 702 and a shaft hole. The shaft core assembly 300 passes through the shaft hole, and the exhaust port houses the electronic airflow monitor 703. The air shroud 701 is used to collect airflow change information overflowing from the air-bearing bearing and further feed it back to the host computer to provide a source signal for the control voltage of the piezoelectric ceramic plate 400.

[0039] The air-bearing electric spindle also includes a controller and a power supply (not shown in the figure). The piezoelectric ceramic plate 400 and the electronic airflow monitoring component are connected to the controller and power supply. The controller controls the expansion and contraction of the piezoelectric ceramic plate 400 based on the airflow information collected by the electronic airflow monitoring component, in order to offset the expansion of the spindle body components due to temperature. The air-controlled piezoelectric ceramic module design scheme intelligently constrains the body expansion, preventing temperature rise and expansion during high-speed spindle machining from causing misalignment of the machine tool clamps and affecting drilling accuracy.

[0040] Embodiments of the present invention also provide a drilling rig including the air-floating electric spindle of any of the above embodiments.

[0041] In the description of this specification, references to terms such as "example," "embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A spindle body assembly, characterized in that, The device includes an inner sleeve and an outer sleeve. The inner sleeve has a first axial inner hole, and the outer sleeve has a second axial inner hole. The inner sleeve is fitted into the second axial inner hole of the outer sleeve to form an integral structure. A piezoelectric ceramic sheet is provided between the inner sleeve and the outer sleeve at least at the mounting clamp position of the spindle body assembly. The piezoelectric ceramic sheet extends from the inner surface to the outer surface along the thickness direction. The inner surface of the piezoelectric ceramic sheet is in contact with the inner sleeve, and the outer surface of the piezoelectric ceramic sheet is in contact with the outer sleeve.

2. The spindle body assembly according to claim 1, characterized in that, The gap between the inner sleeve and the outer sleeve of the machine body at the location where the piezoelectric ceramic sheet is set is smaller than the thickness of the piezoelectric ceramic sheet.

3. The spindle body assembly according to claim 1, characterized in that, The piezoelectric ceramic sheet is in the shape of an annular sleeve, and is fitted between the inner sleeve and the outer sleeve of the machine body.

4. The spindle body assembly according to claim 1, characterized in that, The piezoelectric ceramic sheet is tile-shaped, and multiple piezoelectric ceramic sheets are arranged along the circumference of the main shaft body assembly.

5. The spindle body assembly according to claim 1, characterized in that, The inner sleeve and the outer sleeve of the body are provided with pin holes at corresponding positions, and the inner sleeve and the outer sleeve of the body are fixedly connected by pins provided in the pin holes.

6. The spindle body assembly according to claim 1, characterized in that, The inner sleeve of the machine body is made of aluminum alloy, and the outer sleeve of the machine body is made of steel. The aluminum alloy inner sleeve has an integrated bearing seat inside the mounting clamp position of the spindle body assembly.

7. An air-bearing electric spindle, characterized in that, The spindle assembly includes a spindle core assembly and a spindle body assembly according to any one of claims 1 to 6. The spindle core assembly is supported in the first axial inner hole of the body sleeve by an air bearing. The spindle body assembly is provided with an electronic airflow monitoring component for monitoring the overflow airflow of the air bearing.

8. The air-bearing electric spindle according to claim 7, characterized in that, The spindle body assembly as described in claim 6 includes a bearing mounting cavity inside the bearing housing, an air bearing in the bearing mounting cavity, and an electronic airflow monitoring assembly including an air shroud covering one end of the bearing mounting cavity. The air shroud has an exhaust port and a shaft hole, the spindle assembly passes through the shaft hole, and an electronic airflow monitor is provided in the exhaust port.

9. The air-bearing electric spindle according to claim 7, characterized in that, It also includes a controller and a power supply. The piezoelectric ceramic sheet, the electronic airflow monitoring component, and the controller and power supply are connected. The controller is used to control the expansion and contraction of the piezoelectric ceramic sheet according to the airflow information collected by the electronic airflow monitoring component, so as to offset the expansion of the spindle body assembly caused by temperature.

10. A drilling rig, characterized in that, Includes the air-bearing electric spindle as described in any one of claims 7 to 9.

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