An electric spindle and machine tool

Abstract

The application provides an electric spindle and a machine tool. The electric spindle comprises a shaft core, a flange, a bearing and a displacement sensor. The bearing is sleeved on the outer periphery of the shaft core and is relatively close to the axial front end of the shaft core. The flange is located on the outer periphery of the shaft core. The flange comprises a first part, a second part and a third part. The first part is located at one axial end of the outer ring of the bearing and abuts against the outer ring. The second part is connected to the axial end of the first part away from the outer ring. At least part of the structure of the third part is connected to the outer periphery of the second part. At least part of the structure of the axial end of the second part away from the first part is recessed to form a first recess. At least part of the structure of the displacement sensor is arranged in the first recess. According to the application, the technical problems that the detection surface is easy to be contaminated and the separate occupation of space causes the increase of the volume of the electric spindle can be solved at the same time.

Description

Technical Field

[0001] This invention relates to the field of machine tool technology, and more specifically to an electric spindle and a machine tool. Background Technology

[0002] Electric spindles feature a transmission structure where the built-in motor and machine tool spindle are integrated into one unit. This allows them to better adapt to high-speed, high-precision rotation while minimizing vibration, thus meeting the practical needs of precision machining and high-speed cutting in CNC mold making machine tools. In addition to the built-in spindle motor, electric spindles also integrate lubrication, cooling, encoders, tool clamping, center cooling, and thermal compensation. Compared to traditional mechanical spindles, electric spindles offer advantages such as compact structure, low vibration and noise, stable machining performance, and high machining accuracy.

[0003] Existing electric spindle structures typically include a spindle displacement sensor to detect spindle displacement, with two different installation schemes: 1. The spindle displacement sensor is located outside the electric spindle. However, this scheme is prone to contamination of the detection surface due to the external location of the spindle displacement sensor, resulting in poor detection reliability. 2. The spindle displacement sensor is located inside the electric spindle. However, this scheme requires the spindle displacement sensor to occupy internal space, increasing the size of the electric spindle and causing design redundancy.

[0004] Because existing electric spindle structures either have problems such as the spindle displacement sensor being located outside the electric spindle, making the detection surface easily contaminated, or the displacement sensor being located inside the electric spindle, resulting in separate space occupation and increased electric spindle size, this invention researches and designs an electric spindle and machine tool. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the existing electric spindle structure, which cannot simultaneously solve the problems of easy contamination of the detection surface and the increase in the size of the electric spindle due to its separate space occupation, thereby providing an electric spindle and machine tool.

[0006] To address the above problems, the present invention provides an electric spindle comprising:

[0007] The assembly includes a shaft, a flange, a bearing, and a displacement sensor. The bearing is sleeved on the outer periphery of the shaft and is relatively close to the axial front end of the shaft. The flange is located on the outer periphery of the shaft and includes a first part, a second part, and a third part. The first part is located at one axial end of the outer ring of the bearing and abuts against the outer ring. The second part is connected to one axial end of the first part away from the outer ring. At least a portion of the third part is connected to the outer periphery of the second part. At least a portion of the second part away from the axial end of the first part forms a first groove through a recess. At least a portion of the displacement sensor is disposed in the first groove.

[0008] In some implementations...

[0009] It also includes a front sealing nut, which is also disposed on the outer periphery of a portion of the shaft core. The front sealing nut includes a nut head and a nut post, which are axially connected. The outer diameter of the nut head is larger than the outer diameter of the nut post. A stepped surface is formed at the junction of the outer periphery of the nut head and the outer periphery of the nut post. The stepped surface is opposite to and spaced apart from at least a portion of the structure of the displacement sensor, so that the stepped surface forms the detection surface of the displacement sensor.

[0010] In some implementations...

[0011] At least a portion of the structure of the displacement sensor protrudes from the first groove to form a protruding surface, and the stepped surface is opposite to and spaced apart from at least a portion of the protruding surface so that the stepped surface forms the detection surface of the displacement sensor.

[0012] In some implementations...

[0013] It also includes a sealing ring, which is provided on the radially outer side of the nut head, and one axial end of the sealing ring is connected to at least a portion of the structure of the displacement sensor.

[0014] In some implementations...

[0015] A second groove is formed on the outer circumferential surface of the nut head, and there is a gap between the outer circumferential surface of the nut head and the sealing ring. The second groove and the gap together form a first channel for gas flow. A second channel for gas flow is also formed inside the sealing ring, which extends axially.

[0016] In some implementations...

[0017] One part of the third part is integrally connected to the outer periphery of the second part, and another part of the third part is connected to one axial end of the first part and located on the outer periphery of the sealing ring, so as to lock the sealing ring.

[0018] In some implementations...

[0019] It also includes a front pressure cover, which is sleeved on the outer periphery of the shaft core and located at one axial end of the third part. The front pressure cover is fixed to the third part and abuts against the sealing ring to apply a clamping force to the displacement sensor through the sealing ring. There is a gap between the front pressure cover and the nut head.

[0020] In some implementations...

[0021] It also includes a front sealing spacer, which is also sleeved on the outer periphery of a portion of the shaft core, and one axial end of the front sealing spacer is connected to one axial end of the inner ring of the bearing. The radial inner periphery of the first part of the flange is radially opposite to the front sealing spacer, and the front sealing spacer and the first part form radial and axial limiting.

[0022] In some implementations...

[0023] The front sealing spacer includes a first body, a first protrusion, and a second protrusion. The first protrusion is connected to the radial outer periphery of the first body and extends radially outward. The second protrusion is connected to the radial outer end of the first protrusion and extends along a first axial direction. The first part of the flange includes a second body, a third protrusion, and a fourth protrusion. The third protrusion is connected to the radial inner periphery of the second body and extends radially inward. The fourth protrusion is connected to the radial inner end of the third protrusion and extends along a second axial direction. The first axial direction is opposite to the second axial direction. The second protrusion and the fourth protrusion can form a plug-in fit to form axial and radial limiting between the front sealing spacer and the first part.

[0024] In some implementations...

[0025] When the front sealing nut is also included, and the front sealing nut includes a nut head and a nut post, the axial end face of the first body that is away from the axial bearing is aligned with the axial end face of the nut post.

[0026] In some implementations...

[0027] It also includes a rotary joint connecting rod, a piston, a cylinder head body, and a rotary joint. The rotary joint connecting rod is connected to the axial rear end of the shaft core. The rotary joint has a receiving hole inside. One axial end of the rotary joint connecting rod is inserted into the receiving hole. At least a portion of the structure of the cylinder head body is located on the outer periphery of at least a portion of the structure of the rotary joint connecting rod. At least a portion of the structure of the piston is located on the outer periphery of at least a portion of the structure of the cylinder head body. A first recessed platform is formed on the piston facing the axial front end. A first stepped protrusion is provided on the outer periphery of the cylinder head body at a position opposite to the first recessed platform. The first stepped protrusion engages with the first recessed platform. The first stepped protrusion forms a second recessed platform on the inner periphery of the cylinder head body at a position opposite to the first stepped protrusion. The outer peripheral surface of the rotary joint on one axial side is engaged in the second recessed platform.

[0028] In some implementations...

[0029] The cylinder head body includes a first shaft segment, a second shaft segment, and a third shaft segment. The first shaft segment has a columnar structure and is sleeved on the outer periphery of the rotary joint connecting rod. The radial inner periphery of the second shaft segment is connected to the outer periphery at the shaft end of the first shaft segment. The second shaft segment extends radially outward. One axial end of the third shaft segment is connected to the radial outer portion of the second shaft segment and extends in the axial direction. The second shaft segment and the third shaft segment form the first stepped protrusion.

[0030] The piston includes a fourth shaft segment, a fifth shaft segment, and a sixth shaft segment. The fourth shaft segment has a columnar structure and is sleeved on the radial outer periphery of the first shaft segment. The radial inner periphery of the fifth shaft segment is connected to the outer periphery at the shaft end of the fourth shaft segment. The fifth shaft segment extends radially outward. One axial end of the sixth shaft segment is connected to the radial outer portion of the fifth shaft segment and extends in the axial direction. The fifth shaft segment and the sixth shaft segment form the first recessed platform.

[0031] In some implementations...

[0032] It also includes a hydraulic cylinder, at least a portion of which is fitted around the outer periphery of the piston, and one axial end of the hydraulic cylinder is fixedly connected to the hydraulic cylinder cover. A first cutter auxiliary air intake channel is provided between the inner and outer peripheries of the hydraulic cylinder, and a second cutter auxiliary air intake channel is provided on the hydraulic cylinder cover. The second cutter auxiliary air intake channel is connected to and communicates with the first cutter auxiliary air intake channel, so that air can be sequentially supplied into the interior of the hydraulic cylinder through the second cutter auxiliary air intake channel and the first cutter auxiliary air intake channel.

[0033] In some implementations...

[0034] The cylinder includes a protrusion that protrudes radially toward the piston and connects to the fourth shaft segment of the piston. An air storage groove is provided on the end face of the protrusion toward the fifth shaft segment. An oil cylinder cover hole is provided axially through the cylinder cover body. An oil reservoir is formed between the axial end face of the sixth shaft segment of the piston toward the cylinder cover body and the cylinder cover body, and the cylinder cover hole communicates with the oil reservoir.

[0035] The present invention also provides a machine tool including the aforementioned electric spindle.

[0036] The electric spindle and machine tool provided by this invention have the following beneficial effects:

[0037] 1. This invention forms a first groove by recessing at least a portion of the structure of the second part of the flange inside the electric spindle at one axial end opposite to the first part. At least a portion of the structure of the displacement sensor is disposed in the first groove, thereby allowing the displacement sensor to be housed inside the electric spindle. This effectively solves the problem of detection surface contamination caused by the displacement sensor being disposed on the electric spindle in the prior art. Furthermore, since the displacement sensor is disposed in the groove opened on the end face of the axial end of the second part of the flange, it does not require additional space for the displacement sensor and does not occupy space separately. This allows the displacement sensor to be effectively disposed without increasing the volume of the electric spindle, without occupying extra space, thus solving the problem of design redundancy. Moreover, the built-in design solves the problem of easy contamination of the detection surface and the problem of increased electric spindle volume due to separate space occupation.

[0038] 2. This invention, through the setting of the front sealing nut, forms a stepped surface between the nut column and the nut head that faces the displacement sensor, thus forming a detection surface. The nut structure is integrated with the shaft core, and the displacement sensor is connected to and fixed to the front pressure cover, bearing outer ring, etc. Therefore, the displacement sensor can effectively detect the rotational and displacement parameters of the shaft core by detecting the stepped surface of the nut; providing a detection surface for the displacement sensor; the invention, through the setting of the sealing ring, can form contact with the displacement sensor, thereby fixing and pressing the displacement sensor. Preferably, the outer side of the sealing ring is fixed to the front pressure cover to provide a clamping force for fixing the displacement sensor; the outer peripheral surface of the nut head forms a second groove, and a gap is formed between the outer peripheral surface of the nut head and the sealing ring, which can form a first channel for gas flow, thereby allowing the gas in the gas channel inside the electric spindle to be discharged to the outside of the front pressure cover through the first channel, forming a good seal for the internal shaft core, etc., and preventing external impurities from entering; the sealing ring of this invention also preferably has a second channel inside to ensure that the gas is discharged from the inside of the electric spindle to the outside, improving the sealing performance inside the electric spindle;

[0039] 3. The function of the front sealing spacer of the present invention is to provide a certain degree of sealing for the bearing and the shaft core, preventing gas from the air passage and other structures inside the electric spindle from entering the bearing or shaft core area. The front sealing spacer can effectively position and press the inner ring of the bearing through the structure of the nut column. The front sealing spacer and the first part of the flange form axial and radial limits, but can rotate relative to each other in the circumferential direction. The front sealing spacer is pressed into the inner ring and can rotate, while the flange is connected to the outer ring of the bearing and can be fixed.

[0040] 4. This invention also features a first recessed platform formed by the piston towards its axial front end, and a first stepped protrusion formed by the cylinder cover towards its axial front end, forming a second recessed platform. This allows the rotary joint to be secured within the second recessed platform, enabling deeper insertion of the rotary joint into the electric spindle. This, in turn, allows for a shorter length of the rotary joint connecting rod. The recessed platform and variable diameter design of the cylinder components shorten the length of the central water outlet connecting rod, reducing processing difficulty and increasing strength. Simultaneously, it ensures minimal runout and vibration during operation. The cylinder and cylinder cover of this invention are designed with a broach-assisted air intake channel, and the inner end face of the cylinder is designed with an air storage groove. This increases the air intake volume and ensures more even force distribution during piston upward movement, preventing adhesion. Attached Figure Description

[0041] Figure 1 This is a partial sectional view of the front of the electric spindle of the present invention;

[0042] Figure 2 yes Figure 1 A magnified view of part A in the middle;

[0043] Figure 3 yes Figure 1 A magnified view of part B in the middle section;

[0044] Figure 4 yes Figure 2 A magnified view of part C in the middle;

[0045] Figure 5 yes Figure 2 A magnified view of part D in the middle;

[0046] Figure 6 yes Figure 4 Enlarged view of the mating structure between the middle flange and the displacement sensor;

[0047] Figure 7 yes Figure 5 A close-up view of the middle flange section;

[0048] Figure 8 yes Figure 5 A close-up view of the front-end sealing nut;

[0049] Figure 9yes Figure 5 A magnified view of the front sealing ring;

[0050] Figure 10 Is with Figure 3 Showing partial sectional views of the same component from different perspectives;

[0051] Figure 11 yes Figure 10 Enlarged diagram of the fit between the piston and the cylinder head.

[0052] The reference numerals in the attached figures are as follows:

[0053] 1. Front pressure cap; 2. Sealing ring; 21. Second channel; 3. Flange; 31. First part; 311. Second body; 312. Third protrusion; 313. Fourth protrusion; 32. Second part; 33. Third part; 34. First groove; 4. Front water ring; 5. Bearing seat; 6. Front sealing nut; 61. Nut head; 62. Nut post; 63. Stepped surface; 64. Second groove; 7. Front sealing spacer; 71. First body; 72. First protrusion; 73. Second protrusion; 8. Bearing; 81. Outer ring; 82. Inner ring; 9. Shaft core; 10. Pipeline disc; 11. Hydraulic cylinder; 111. First puller auxiliary air intake channel; 112 113. Protrusion; 12. Air reservoir; 13. Piston; 14. First recessed platform; 15. Fourth shaft section; 16. Fifth shaft section; 17. Sixth shaft section; 18. Oil reservoir; 19. Cylinder head; 10. First stepped protrusion; 10. Second recessed platform; 11. Second puller auxiliary air intake channel; 12. First shaft section; 13. Second shaft section; 14. Third shaft section; 15. Cylinder head hole; 16. Rotary joint; 17. Receiving hole; 18. Rotary joint connecting rod; 19. Proximity switch sensing plate; 10. Proximity switch base; 10. Proximity switch; 111. Set screw; 12. Displacement sensor; 13. Protrusion surface. Detailed Implementation

[0054] 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0055] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0056] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0057] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0058] like Figures 1 to 11 As shown, the present invention provides an electric spindle, which includes:

[0059] The assembly includes a shaft core 9, a flange 3, a bearing 8, and a displacement sensor 20. The bearing 8 is sleeved on the outer periphery of the shaft core 9 and is relatively close to the axial front end of the shaft core 9 (the axial front end is the two ends corresponding to the axial rear end of the rotary joint connecting rod). The flange 3 is located on the outer periphery of the shaft core 9 and includes a first part 31, a second part 32, and a third part 33. The first part 31 is located at one axial end of the outer ring 81 of the bearing 8 and abuts against the outer ring 81. The second part 32 is connected to one axial end of the first part 31 away from the outer ring 81. At least a portion of the structure of the third part 33 is connected to the outer periphery of the second part 32. At least a portion of the structure of the second part 32 away from the axial end of the first part 31 forms a first groove 34 by recessing. At least a portion of the structure of the displacement sensor 20 is disposed in the first groove 34.

[0060] This invention addresses the problem of contamination of the detection surface caused by the placement of the displacement sensor inside the electric spindle. At least a portion of the structure of the second part of the flange inside the electric spindle is recessed to form a first groove on the axial end opposite to the first part. This effectively solves the problem of contamination of the detection surface caused by the displacement sensor being placed inside the electric spindle in the prior art. Furthermore, since the displacement sensor is placed in the groove on the end face of the axial end of the second part of the flange, it does not require additional space for the displacement sensor and does not occupy space separately. This allows for the effective placement of the displacement sensor without increasing the size of the electric spindle, eliminating design redundancy and solving the problem of external contamination. The built-in design also solves the problem of external contamination, thus simultaneously addressing the technical problems of easy contamination of the detection surface and increased electric spindle size due to separate space occupation.

[0061] This invention integrates a displacement sensor, secured by an airtight ring and screws. Located at the air vent of the airtight ring, it features an air curtain for protection, ensuring the cleanliness and reliability of the detection surface. The displacement sensor is embedded within the existing components and mates with the front nut, eliminating the need for separate space design and ensuring structural compactness. It solves the problems of easy contamination and poor reliability associated with externally mounted spindle displacement sensors, and also addresses the issue of redundant design due to the space occupied by an internally mounted sensor. Furthermore, the bearing nut incorporates a triangular toothed airtight structure, with the inner end face of the outer circle serving as the displacement sensor's detection surface. This allows the nut to function as both an airtight seal and a detection surface, resulting in a more compact front-end space.

[0062] In some implementations...

[0063] It also includes a front sealing nut 6, which is also disposed on the outer periphery of a portion of the shaft core 9. The front sealing nut 6 includes a nut head 61 and a nut post 62. The nut head 61 and the nut post 62 are connected axially, and the outer diameter of the nut head 61 is larger than the outer diameter of the nut post 62. A stepped surface 63 is formed at the junction of the outer periphery of the nut head 61 and the outer periphery of the nut post 62. The stepped surface 63 is opposite to and spaced apart from at least a portion of the structure of the displacement sensor 20, so that the stepped surface 63 forms the detection surface of the displacement sensor 20.

[0064] This invention, through the setting of the front sealing nut, forms a step surface between the nut column and the nut head that faces the displacement sensor, thereby forming a detection surface. The nut structure is integrated with the shaft core, and the displacement sensor is connected and fixed to the front cover, bearing outer ring, etc. Therefore, the displacement sensor can effectively detect the rotation parameters and displacement parameters of the shaft core by detecting the step surface of the nut; thus providing a detection surface for the displacement sensor.

[0065] In some implementations...

[0066] At least a portion of the structure of the displacement sensor 20 protrudes from the first groove 34 to form a protruding surface 201. The stepped surface 63 is opposite to at least a portion of the protruding surface 201 and is spaced apart so that the stepped surface 63 forms the detection surface of the displacement sensor 20.

[0067] This is the preferred fit between the displacement sensor and the stepped surface of the nut in this invention. Preferably, at least part of the displacement sensor is provided to protrude from the first groove, thereby forming a protruding surface. This makes the displacement detection between the sensor and the spaced stepped surfaces more accurate and improves the detection precision.

[0068] In some implementations...

[0069] It also includes a sealing ring 2, which is provided on the radially outer side of the nut head 61, and one axial end of the sealing ring 2 is connected to at least a part of the structure of the displacement sensor 20.

[0070] The present invention enables the displacement sensor to be connected to the sealing ring, thereby fixing and pressing the displacement sensor. Preferably, the outer part of the sealing ring is fixed to the front cover to provide a clamping force for fixing the displacement sensor.

[0071] In some implementations...

[0072] A second groove 64 is provided on the outer peripheral surface of the nut head 61, and there is a gap between the outer peripheral surface of the nut head 61 and the sealing ring 2. The second groove 64 and the gap together can form a first channel for gas flow. A second channel 21 for gas flow is also formed inside the sealing ring 2, which runs through the axial direction.

[0073] The outer peripheral surface of the nut head of the present invention forms a second groove, and a gap is formed between the outer peripheral surface of the nut head and the sealing ring, which can form a first channel for gas flow, thereby allowing the gas in the gas channel inside the electric spindle to be discharged to the outside of the front pressure cover through the first channel, forming a good seal for the internal shaft core, etc., and preventing external impurities from entering; the sealing ring of the present invention is also preferably provided with a second channel inside to ensure that the gas is discharged from the inside of the electric spindle to the outside, thereby improving the sealing performance inside the electric spindle.

[0074] In some implementations...

[0075] One part of the third part 33 is integrally connected to the outer periphery of the second part 32, and another part of the third part 33 is connected to one axial end of the first part and located on the outer periphery of the sealing ring 2 so as to lock the sealing ring 2.

[0076] This invention utilizes a flange structure to fix and snap the sealing ring structure, preventing the sealing ring from rotating with the nut and improving the sealing performance between nuts.

[0077] In some implementations...

[0078] It also includes a front pressure cover 1, which is sleeved on the outer periphery of the shaft core 9 and located at one axial end of the third part 33. The front pressure cover 1 is fixed to the third part 33 and abuts against the sealing ring 2 to apply a clamping force to the displacement sensor 20 through the sealing ring 2. There is a gap between the front pressure cover 1 and the nut head 61.

[0079] This invention can effectively fix the flange and the sealing ring by using the front pressure cover, thereby applying a clamping force to the displacement sensor using the sealing ring, thus achieving a fixed and stable setting of the displacement sensor and ensuring stable detection.

[0080] In some implementations...

[0081] It also includes a front sealing spacer 7, which is also sleeved on the outer periphery of a portion of the shaft core 9, and one axial end of the front sealing spacer 7 is connected to one axial end of the inner ring 82 of the bearing 8. The radial inner periphery of the first portion 31 of the flange 3 is radially opposite to the front sealing spacer 7, and the front sealing spacer 7 and the first portion 31 form radial and axial limiting.

[0082] The function of the front sealing spacer of the present invention is to provide a certain degree of sealing for the bearing and the shaft core, preventing gas from the air passage and other structures inside the electric spindle from entering the bearing or shaft core area. The front sealing spacer can effectively position and press the inner ring of the bearing through the structure of the nut column. The front sealing spacer and the first part of the flange form axial and radial limits, but can rotate relative to each other in the circumferential direction. The front sealing spacer is pressed into the inner ring and can rotate, while the flange is connected to the outer ring of the bearing and can be fixed.

[0083] In some implementations...

[0084] The front sealing ring 7 includes a first body 71, a first protrusion 72, and a second protrusion 73. The first protrusion 72 is connected to the radial outer periphery of the first body 71 and extends radially outward. The second protrusion 73 is connected to the radial outer end of the first protrusion 72 and extends along a first axial direction. The first part 31 of the flange 3 includes a second body 311, a third protrusion 312, and a fourth protrusion 313. The third protrusion 312 is connected to the radial inner periphery of the second body 311 and extends radially inward. The fourth protrusion 313 is connected to the radial inner end of the third protrusion 312 and extends along a second axial direction. The first axial direction is opposite to the second axial direction. The second protrusion 73 and the fourth protrusion 313 can form a plug-in fit to form axial and radial limiting between the front sealing ring 7 and the first part 31.

[0085] This is a preferred structural form of the front sealing spacer of the present invention. The first and second protrusions formed can engage with the third and fourth protrusions of the flange to achieve the purpose and function of axial and radial limiting between the flange and the front sealing spacer.

[0086] In some implementations...

[0087] When the invention also includes a front sealing nut 6, which comprises a nut head 61 and a nut post 62, the axial end face of the first body 71 facing away from the axial bearing 8 is aligned with the axial end face of the nut post 62. In this invention, the axial end face of the nut post also abuts against the first body of the front sealing spacer. Both the front sealing spacer and the nut are integral structures that rotate with the shaft core. Through the nut and the front sealing spacer, the inner ring of the bearing can be effectively axially tightened and limited.

[0088] The sealing structure of the present invention:

[0089] An air inlet is located at the rear end of the electric spindle, and an air-sealing flow channel is located inside the spindle housing. The air-sealing flow channels between various parts are sealed with O-rings. One end of the air inlet is connected to an air pipe to introduce high-pressure gas supplied by an air compressor, and the other end is connected to the air-sealing flow channel inside the spindle housing to introduce high-pressure gas into the spindle, forming an air seal. The front end of the spindle consists of a front pressure cover 1, a flange 3 (preferably an annular spray flange), a sealing ring 2 (preferably an air-sealing ring), a front sealing nut 6, and a shaft core 9, forming a sealing assembly. The annular spray flange has an annular groove and a protrusion, and the front sealing nut 6 also has an annular groove and a protrusion. The annular groove and protrusion on the annular spray flange can be matched with the corresponding structure on the front sealing nut, and the two together form a labyrinth seal. Specifically, an annular air reservoir is formed on the annular spray flange and connected to the air-sealing flow channel on the spindle housing. Several air outlets are radially formed on the air-sealing ring, with more than one outlet. The air-sealing ring and the annular spray flange are interference-fitted. The sealing ring and the front sealing nut are clearance-fitted, and the outer circumference of the front sealing nut has double rows of triangular toothed air grooves, forming the first gap. The front pressure cover is connected to the annular spray flange, and a second gap is formed between the front pressure cover, the air-sealing ring, and the shaft core. The first and second gaps are interconnected. High-pressure gas is finally discharged from the outside of the spindle through the gap between the front pressure cover 1 and the shaft core 9, forming an air curtain to protect the gaps in the spindle body. After the annular air reservoir is filled with gas, it exits through the radial air outlets on the air-sealing ring, forming a high-pressure air curtain at the first and second gaps, preventing external impurities from entering the spindle. The air-sealing structure and labyrinth seal structure at the front end of the overall spindle constitute a double seal at the front end of the spindle, with a very significant sealing effect.

[0090] In addition to isolating and protecting impurities on the outside of the spindle, the air curtain of this invention also cleans and protects the displacement sensor 20 built into the spindle. The displacement sensor is built-in and fixed by an air-sealing ring and screws. Because it is located at the air vent of the air-sealing ring, it is protected by the air curtain, ensuring the cleanliness and reliability of the detection surface. The displacement sensor is embedded in the ring-spray flange and engages with the front nut, eliminating the need for a separate space for fixation and ensuring a compact structure.

[0091] In some implementations...

[0092] It also includes a rotary joint rod 15, a piston 12, a cylinder head 13, and a rotary joint 14. The rotary joint rod 15 is connected to the axial rear end of the shaft core 9. The rotary joint 14 has a receiving hole 141 inside, and one axial end of the rotary joint rod 15 is inserted into the receiving hole 141. At least a portion of the structure of the cylinder head 13 is located on the outer periphery of at least a portion of the structure of the rotary joint rod 15, and at least a portion of the structure of the piston 12 is located on the outer periphery of at least a portion of the structure of the cylinder head 13. A first recessed platform 121 is formed on the piston 12 in the direction of the axial front end. A first stepped protrusion 131 is provided on the outer periphery of the cylinder head 13 opposite to the first recessed platform 121. The first stepped protrusion 131 is engaged with the first recessed platform 121. The first stepped protrusion 131 forms a second recessed platform 132 on the inner periphery of the cylinder head 13 opposite to the first stepped protrusion 131. The outer peripheral surface of the rotary joint 14 on one axial side is engaged in the second recessed platform 132.

[0093] This invention also features a first recessed platform formed by the piston towards its axial front end, and a first stepped protrusion formed by the cylinder cover towards its axial front end, forming a second recessed platform. This allows the rotary joint to be secured within the second recessed platform, enabling it to be inserted deeper into the electric spindle. This, in turn, allows the rotary joint connecting rod to be manufactured in a shorter length. The recessed platform and variable diameter design of the cylinder components shorten the length of the center outlet connecting rod, reducing processing difficulty and increasing strength. Simultaneously, it ensures the circular runout and vibration values ​​of the connecting rod during operation.

[0094] In some implementations...

[0095] The cylinder head 13 includes a first shaft segment 134, a second shaft segment 135, and a third shaft segment 136. The first shaft segment 134 has a columnar structure and is sleeved on the outer periphery of the rotary joint connecting rod 15. The radial inner periphery of the second shaft segment 135 is connected to the outer periphery at the shaft end of the first shaft segment 134. The second shaft segment 135 extends radially outward. One axial end of the third shaft segment 136 is connected to the radial outer portion of the second shaft segment 135 and extends in the axial direction. The second shaft segment 135 and the third shaft segment 136 form the first stepped protrusion 131, preferably in an "L" shape in the longitudinal section.

[0096] The piston 12 includes a fourth shaft segment 122, a fifth shaft segment 123, and a sixth shaft segment 124. The fourth shaft segment 122 is a columnar structure sleeved on the radial outer periphery of the first shaft segment 124. The radial inner periphery of the fifth shaft segment 123 is connected to the outer periphery at the shaft end of the fourth shaft segment 122. The fifth shaft segment 123 extends radially outward. One axial end of the sixth shaft segment 124 is connected to the radial outer portion of the fifth shaft segment 123 and extends in the axial direction. The fifth shaft segment and the sixth shaft segment form the first recess 121. The second shaft segment and the third shaft segment form an "L" shape in the longitudinal section.

[0097] This is a further preferred structural form between the piston and the cylinder head of the present invention, which can form the aforementioned first recessed platform, first stepped protrusion and second recessed platform structure, thereby allowing the rotary joint to be inserted deeper into the interior, effectively shortening the length of the central water outlet structure, enhancing strength and reducing vibration.

[0098] In some implementations...

[0099] It also includes a hydraulic cylinder 11, at least a portion of which is fitted around the outer periphery of the piston 12, and one axial end of the hydraulic cylinder 11 is fixedly connected to the hydraulic cylinder cover 13; a first cutter auxiliary air intake channel 111 is provided between the inner and outer peripheries of the hydraulic cylinder 11, and a second cutter auxiliary air intake channel 133 is provided on the hydraulic cylinder cover 13, the second cutter auxiliary air intake channel 133 being connected to and communicating with the first cutter auxiliary air intake channel 111, so that air can be sequentially supplied into the interior of the hydraulic cylinder 11 through the second cutter auxiliary air intake channel 133 and the first cutter auxiliary air intake channel 111.

[0100] The oil cylinder and cylinder cover of the present invention are designed with a puller-assisted air intake channel, and the inner end face of the oil cylinder is designed with an air storage groove, which can improve the air intake volume and make the force more uniform when the piston moves upward, and prevent sticking.

[0101] In some implementations...

[0102] The cylinder 11 includes a protrusion 112 that protrudes radially toward the piston 12 and connects with the fourth shaft segment 122 of the piston 12. An air storage groove 113 is provided on the end face of the protrusion 112 facing the fifth shaft segment 123. An oil cylinder cover hole 137 is provided axially through the cylinder cover body 13. An oil reservoir 125 is formed between the axial end face of the sixth shaft segment 124 of the piston 12 facing the cylinder cover body 13 and the cylinder cover body 13. The cylinder cover hole 137 communicates with the oil reservoir 125.

[0103] This invention also optimizes the sinking space of the cylinder head by adopting a recessed platform design on the piston end face. The cylinder head adopts a stepped variable diameter design, which brings the central rotary joint closer to the end face of the tie rod, shortens the length of the central water outlet connecting rod, reduces the processing difficulty, increases the strength, and ensures the circular runout level of the connecting rod. This solves the problem of the rotary joint being far away from the end face of the tie rod and the central water outlet connecting rod being too long.

[0104] The invention also incorporates a cutter-assisted air intake channel on the cylinder body and an air storage groove on the inner end face of the cylinder, which makes the force more even when the piston moves upward and prevents sticking.

[0105] The present invention preferably incorporates a double fixing thread on the cylinder body for the proximity switch, which ensures the reliability of the proximity switch fixing and the ease of wiring; thus solving the problem of difficult wiring out of the proximity switch's built-in conduit plate.

[0106] The hydraulic cylinder structure of this invention:

[0107] The hydraulic cylinder assembly consists of a hydraulic cylinder 11, a piston 12, a cylinder cover 13, and sealing rings. The cylinder cover is designed with an oil inlet and an air inlet. An oil reservoir is designed between the outer end face of the piston 12 and the cylinder cover 13, allowing for more even force distribution during tool release. When the spindle releases the tool, oil enters the reservoir through the oblique hole in the cylinder cover, creating pressure that pushes the piston forward, causing the proximity switch sensor plate of the pull rod system to move forward, completing the tool release action. The cylinder body is designed with a tool release auxiliary air intake channel, and the inner end face of the cylinder is designed with an air reservoir to ensure more even force distribution during piston upward movement and prevent sticking. High-pressure gas enters the air reservoir on the inner end face of the cylinder through the holes in the cylinder cover and the cylinder, creating pressure that pushes the piston backward, disengaging from the pull rod and completing the tool release action.

[0108] The piston 12 features a countersunk design on its end face, while the cylinder head 13 employs a stepped diameter design. This design, in conjunction with the piston's countersunk design, optimizes the downward space of the cylinder head 13. The stepped diameter design of the cylinder head 13 also incorporates a rotary joint seat hole, allowing the central rotary joint to be closer to the tie rod end face. This shortens the length of the central water outlet connecting rod, reduces machining difficulty, increases strength, and ensures the circular runout level of the connecting rod.

[0109] A proximity switch sensor is installed on the side of the hydraulic cylinder. The proximity switch sensor holder is threadedly connected to the hydraulic cylinder, and a screw hole is also provided on the small end face of the hydraulic cylinder body, so that the proximity switch holder has a double-threaded locking mechanism for reliable fixation. The double fixing threads of the proximity switch designed on the hydraulic cylinder body ensure the reliability of the proximity switch fixation and the ease of wiring.

[0110] The present invention also provides a machine tool including the aforementioned electric spindle.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. An electric spindle, characterized by: Comprising: a shaft core (9), a flange (3), a bearing (8) and a displacement sensor (20), the bearing (8) is sleeved on the outer periphery of the shaft core (9) and is relatively close to the axial front end of the shaft core (9), the flange (3) is located on the outer periphery of the shaft core (9), the flange (3) comprises a first part (31), a second part (32) and a third part (33), the first part (31) is located at one end of the outer ring (81) of the bearing (8) in the axial direction and abuts against the outer ring (81), the second part (32) is connected to the axial end of the first part (31) away from the outer ring (81), at least part of the structure of the third part (33) is connected to the outer periphery of the second part (32), at least part of the structure of the axial end of the second part (32) away from the first part (31) forms a first groove (34) by recessing, and at least part of the structure of the displacement sensor (20) is arranged in the first groove (34); It also comprises a front end sealing nut (6), the front end sealing nut (6) is also arranged on the outer periphery of part of the shaft segment of the shaft core (9), the front end sealing nut (6) comprises a nut head (61) and a nut column (62), the nut head (61) and the nut column (62) are connected in the axial direction, and the outer diameter of the nut head (61) is greater than the outer diameter of the nut column (62), the outer periphery of the nut head (61) and the outer periphery of the nut column (62) are connected to form a stepped surface (63), the stepped surface (63) is opposite and spaced apart from at least part of the structure of the displacement sensor (20), so that the stepped surface (63) forms a detection surface of the displacement sensor (20); at least part of the structure of the displacement sensor (20) protrudes from the first groove (34) to form a protruding surface (201); It also comprises a sealing ring (2), the sealing ring (2) is arranged on the radial outer side of the nut head (61), a second groove (64) is formed on the outer peripheral surface of the nut head (61), and a gap is formed between the outer peripheral surface of the nut head (61) and the sealing ring (2), the second groove (64) and the gap can jointly form a first channel for gas flow.

2. The electric spindle according to claim 1, characterized in that: the stepped surface (63) is opposite and spaced apart from at least part of the surface of the protruding surface (201) to form a detection surface of the displacement sensor (20).

3. The electric spindle according to claim 1, characterized in that: one end of the sealing ring (2) in the axial direction is connected to at least part of the structure of the displacement sensor (20).

4. The electric spindle according to claim 3, characterized in that: the inside of the sealing ring (2) also forms a second channel (21) for gas flow which penetrates in the axial direction.

5. The electric spindle according to claim 3, characterized in that: One part of the third part (33) is connected with the outer periphery of the second part (32) as a whole, and the other part of the third part (33) is connected with the one part at an axial end and located at the outer periphery of the sealing ring (2) to enable clamping of the sealing ring (2).

6. The electric spindle according to claim 3, characterized in that: Further comprising a front gland (1) which is sleeved on the outer periphery of the shaft core (9) and located at an axial end of the third part (33), the front gland (1) is fixedly connected with the third part (33), and the front gland (1) abuts against the sealing ring (2) to apply a pressing force on the displacement sensor (20) through the sealing ring (2); there is a gap between the front gland (1) and the nut head (61).

7. The electric spindle according to any one of claims 1-6, characterized in that: Further comprising a front end sealing spacer ring (7) which is also sleeved on the outer periphery of a part of the shaft segment of the shaft core (9), and an axial end of the front end sealing spacer ring (7) is connected with an axial end of the inner ring (82) of the bearing (8), the radial inner periphery of the first part (31) of the flange (3) is opposite to the front end sealing spacer ring (7) in the radial direction, and the front end sealing spacer ring (7) and the first part (31) form radial and axial limiting.

8. The electric spindle according to claim 7, characterized in that: The front end sealing spacer ring (7) comprises a first main body (71), a first protrusion (72) and a second protrusion (73), the first protrusion (72) is connected with the radial outer periphery of the first main body (71) and extends towards the radial outer side, the second protrusion (73) is connected with the radial outer end of the first protrusion (72) and extends along a first axial direction, the first part (31) of the flange (3) comprises a second main body (311), a third protrusion (312) and a fourth protrusion (313), the third protrusion (312) is connected with the radial inner periphery of the second main body (311) and extends towards the radial inner side, the fourth protrusion (313) is connected with the radial inner end of the third protrusion (312) and extends along a second axial direction, the first axial direction is opposite to the second axial direction, the second protrusion (73) and the fourth protrusion (313) can form a plug-in fit to form the axial and radial limiting between the front end sealing spacer ring (7) and the first part (31).

9. The electric spindle according to claim 8, characterized in that: When further comprising a front end sealing nut (6), the front end sealing nut (6) comprises a nut head (61) and a nut column (62), and the axial end surface of the first main body (71) away from the bearing (8) is arranged opposite to the axial end surface of the nut column (62).

10. The electric spindle according to any one of claims 1-6, characterized in that: Further comprising a swivel joint connecting rod (15), a piston (12), a cylinder cover body (13) and a swivel joint (14), the swivel joint connecting rod (15) is connected to the axial rear end of the shaft core (9), the swivel joint (14) has a receiving hole (141) inside, the axial end of the swivel joint connecting rod (15) is inserted into the receiving hole (141), at least part of the structure of the cylinder cover body (13) is located outside at least part of the structure of the swivel joint connecting rod (15), at least part of the structure of the piston (12) is located outside at least part of the structure of the cylinder cover body (13), the first sunken platform (121) is recessed on the piston (12) towards the direction of the axial front end, the first stepped convex part (131) is arranged at the position opposite to the first sunken platform (121) on the outer periphery of the cylinder cover body (13), the first stepped convex part (131) is clamped and matched with the first sunken platform (121), the second sunken platform (132) is formed at the position opposite to the first stepped convex part (131) on the inner periphery of the cylinder cover body (13) through the first stepped convex part (131), and the outer peripheral surface of the axial side of the swivel joint (14) is clamped in the second sunken platform (132).

11. The electric spindle according to claim 10, characterized in that: The cylinder cover body (13) comprises a first shaft section (134), a second shaft section (135) and a third shaft section (136), the first shaft section (134) is in a columnar structure, is sleeved on the outer periphery of the swivel joint connecting rod (15), the radial inner periphery of the second shaft section (135) is connected with the outer periphery at the axial end of the first shaft section (134), the second shaft section (135) extends towards the radial outer side, the axial end of the third shaft section (136) is connected with the radial outer side part of the second shaft section (135) and extends in the axial direction, and the second shaft section (135) and the third shaft section (136) form the first stepped convex part (131); The piston (12) comprises a fourth shaft section (122), a fifth shaft section (123) and a sixth shaft section (124), the fourth shaft section (122) is in a columnar structure and is sleeved on the radial outer periphery of the first shaft section (134), the radial inner periphery of the fifth shaft section (123) is connected with the outer periphery at the axial end of the fourth shaft section (122), the fifth shaft section (123) extends towards the radial outer side, the axial end of the sixth shaft section (124) is connected with the radial outer side part of the fifth shaft section (123) and extends in the axial direction, and the fifth shaft section and the sixth shaft section form the first sunken platform (121).

12. The electric spindle according to claim 11, characterized in that: Further comprising an oil cylinder (11), at least part of structure of the oil cylinder (11) is sleeved on the outer periphery of the piston (12), and an axial end of the oil cylinder (11) is fixedly connected with the oil cylinder cover body (13); a first pull knife auxiliary air inlet channel (111) is further arranged between the inner periphery and the outer periphery of the oil cylinder (11), a second pull knife auxiliary air inlet channel (133) is arranged on the oil cylinder cover body (13), the second pull knife auxiliary air inlet channel (133) is butt-jointed and communicated with the first pull knife auxiliary air inlet channel (111), so that air can be supplied into the inside of the oil cylinder (11) through the second pull knife auxiliary air inlet channel (133) and the first pull knife auxiliary air inlet channel (111) in sequence.

13. The electric spindle according to claim 12, characterized in that: The oil cylinder (11) comprises a protruding part (112) radially protruding towards the piston (12) and being connected with the fourth shaft section (122) of the piston (12), an air storage groove (113) is arranged on the end face of the protruding part (112) towards the fifth shaft section (123); an oil cylinder cover body hole (137) is arranged through the oil cylinder cover body (13) in the axial direction, the sixth shaft section (124) of the piston (12) is spaced from the axial end face of the oil cylinder cover body (13) to form an oil storage cavity (125), and the oil cylinder cover body hole (137) is communicated with the oil storage cavity (125).

14. A machine tool characterized by: The electric spindle comprises any one of claims 1-13.

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