Electric spindle and machine tool

Abstract

The invention provides an electric spindle and a machine tool, and belongs to the field of electric spindles. The motorized spindle includes: a spindle core; the bearing seat is arranged on the periphery of the shaft core in a sleeving mode, an opening facing the axial side of the shaft core is defined by the bearing seat and the periphery of the shaft core, and the bearing seat is arranged on the periphery of the shaft core in a sleeving mode and arranged in the opening; the spacer ring assembly is arranged on the periphery of the shaft core in a sleeving mode, located on the opening side and used for axially pre-tightening a bearing arranged in the bearing seat; a protruding structure used for being in interference fit with the inner circumferential face of the spacer ring assembly is arranged on the periphery of the shaft core in a protruding mode, and in the axis direction of the shaft core, the protruding height of the protruding structure gradually increases from the side away from the bearing to the side close to the bearing. According to the bearing pre-tightening device, the protruding structure with the protruding height gradually increasing from the side away from the bearing to the side close to the bearing is arranged on the periphery of the shaft core in the protruding mode, the distance ring assembly and the protruding structure are arranged to be in interference fit, and online pre-tightening operation can be conducted on the bearing through the distance ring assembly arranged on the shaft core in a sleeving mode.

Description

Technical Field

[0001] The present application relates to the technical field of electric spindles, and in particular to an electric spindle and a machine tool. Background Art

[0002] The electric spindle is a new technology that integrates the machine tool spindle and the spindle motor. The spindle is directly driven by a built-in motor, eliminating the gear, belt or coupling drive of the traditional spindle, thereby shortening the transmission chain length of the machine tool spindle to zero. It is widely used in the manufacturing of cutting-edge products such as precision molds, automobiles, ships, and aerospace. The electric spindle has a complex structure. The shaft core is the core part of the electric spindle, and the bearings, motors and other parts are assembled on it. The overall assembly accuracy determines the rotation accuracy of the electric spindle.

[0003] The bearing is the core component of the electric spindle, transmitting the torque of the rotating shaft core. More than 85% of the failures of most electric spindles are caused by bearing damage. The main factors affecting the life of the bearing are the preload and internal cleaning of the bearing. Cutting fluid or other impurities entering the bearing will cause the bearing to rotate unsteadily, reducing the service life of the bearing, thus causing the electric spindle failure.

[0004] Bearing preload can prevent the bearing from heating up due to incorrect installation position during operation. In other words, proper bearing preload can make the bearing run smoothly and increase the service life of the bearing.

[0005] At present, the preload of the electric spindle bearings is done by adjusting the bearing seat and the bearing to the assembly position before assembly. During the assembly process on the shaft core, the actual situation does not match the theory, so the bearing preload adjustment is performed multiple times, which increases the workload and the preload effect is not good. Therefore, it is particularly important to preload the bearings on the shaft core. Summary of the invention

[0006] The embodiment of the present application provides an electric spindle and a machine tool, which has a protrusion structure with a protrusion height increasing from the side away from the bearing to the side close to the bearing protruding from the outer periphery of the shaft core, and sets the spacer ring assembly and the protrusion structure to be interference fit, so that the bearing can be pre-tightened online through the spacer ring assembly sleeved on the shaft core, without adjusting the assembly position of the bearing and the bearing seat in advance. Specifically:

[0007] A first aspect of an embodiment of the present application provides an electric spindle, comprising:

[0008] Axis core;

[0009] The bearing seat and the bearing, the bearing seat is sleeved on the outer periphery of the shaft core and defines an opening facing one axial side of the shaft core with the outer periphery of the shaft core, and the bearing is sleeved on the outer periphery of the shaft core and placed in the opening;

[0010] A spacer ring assembly is sleeved on the outer periphery of the shaft core and is located on the opening side, and is used to axially preload the bearing placed in the bearing seat;

[0011] The outer periphery of the shaft core is convexly provided with a protruding structure for interference fit with the inner periphery of the spacer ring assembly, and in the axial direction of the shaft core, the protruding height of the protruding structure increases from the side away from the bearing to the side close to the bearing.

[0012] In the above technical solution, the protrusion structure includes a thread structure formed on the outer periphery of the shaft core, and the thread structure spirally extends from a side away from the bearing to a side close to the bearing;

[0013] The tooth height of the thread teeth of the thread structure increases from the side far away from the bearing to the side close to the bearing.

[0014] In the above technical solution, the thread structure has a plurality of adjacent thread teeth in the axial direction of the shaft core;

[0015] The tooth height difference between two adjacent thread teeth is within the first tooth height difference range.

[0016] In the above technical solution, the tooth height difference between two adjacent thread teeth is e, wherein 0.005 mm<e<0.01 mm.

[0017] In the above technical solution, the protrusion structure includes a plurality of annular protrusions formed on the outer periphery of the shaft core;

[0018] The protrusion heights of the plurality of annular protrusions are increased gradually from a side away from the bearing to a side close to the bearing.

[0019] In the above technical solution, the outer periphery of the shaft core is formed with a bearing seat mounting position, a bearing mounting position and a spacer ring assembly mounting position, and a convex structure is formed at the spacer ring assembly mounting position;

[0020] A first step is formed between the bearing seat mounting position and the bearing mounting position, and a second step is formed between the bearing mounting position and the spacer ring assembly mounting position;

[0021] The first step is used to axially limit the bearing when the bearing is sleeved on the outer periphery of the shaft core, and the second step is used to axially limit the spacer ring assembly when the spacer ring assembly is sleeved on the outer periphery of the shaft core.

[0022] In the above technical solution, the spacer ring assembly includes a first spacer ring and a second spacer ring matched in the axial direction of the shaft core, the inner circumference of the first spacer ring is used for interference fit with the outer circumference of the shaft core, the second spacer ring is fixed on the bearing seat, and the inner circumference of the second spacer ring is used for clearance fit with the outer circumference of the first spacer ring;

[0023] A sealing structure is formed between the first spacer ring and the second spacer ring which are clearance-fitted.

[0024] In the above technical solution, the sealing structure includes a sealing section formed between the first spacer ring and the second spacer ring matching surface, and the sealing section includes a first sealing section, a second sealing section and a third sealing section formed along the sealing path;

[0025] The first sealing section and the third sealing section are labyrinth seals, and the second sealing section is a gap seal.

[0026] In the above technical solution, the first spacer ring is sequentially formed with a first sealing position, a second sealing position and a third sealing position from the side away from the bearing to the side close to the bearing, the first sealing position cooperates with the second spacer ring to form a first sealing section, the second sealing position cooperates with the second spacer ring to form a second sealing section, and the third sealing position cooperates with the second spacer ring to form a third sealing section;

[0027] The first sealing position includes a first ring tooth that obliquely protrudes along the radial direction of the first spacer ring, and the third sealing position includes a second ring tooth that obliquely protrudes along the axial direction of the first spacer ring;

[0028] A dirt storage groove is formed on the tooth surface of the first ring tooth and / or the tooth surface of the second ring tooth.

[0029] In the above technical solution, the first ring teeth obliquely protruding along the radial direction of the shaft core form an angle a with the axial direction of the shaft core;

[0030] The second ring teeth obliquely protruding along the axial direction of the shaft core form an angle a1 with the radial direction of the shaft core;

[0031] Among them, 45°≤a=a1≤60°.

[0032] In the above technical solution, the tooth width of the first ring tooth in the axial direction of the shaft core is b, and the tooth height of the first ring tooth in the radial direction of the shaft core is c;

[0033] The tooth width of the second ring tooth in the radial direction of the shaft core is b1, and the tooth height of the second ring tooth in the axial direction of the shaft core is c1;

[0034] Where b and c satisfy: 0.2

[0035] In the above technical solution, the clearance fit between the first spacer ring and the second spacer ring is h;

[0036] Where h satisfies: 0.3mm <h<0.5mm。

[0037] A second aspect of an embodiment of the present application provides a machine tool, which includes the electric spindle provided by the first aspect of an embodiment of the present application.

[0038] ​After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0039] In the embodiment of the present application, a protrusion structure is provided on the outer periphery of the shaft core, the protrusion height of which increases gradually from the side away from the bearing to the side close to the bearing, and the spacer ring assembly and the protrusion structure are arranged to be interference fit. In this way, the bearing can be pre-tightened online by means of the spacer ring assembly sleeved on the shaft core, without the need to adjust the assembly position of the bearing and the bearing seat in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the exploded structure of the electric spindle in the embodiment of the present application;

[0041] Figure 2 This is a schematic diagram of the three-dimensional structure of the first spacer ring in the embodiment of the present application;

[0042] Figure 3 This is a schematic cross-sectional structural diagram of the first spacer ring in the embodiment of the present application;

[0043] Figure 4 This is a schematic diagram of the three-dimensional structure of the second spacer ring in the embodiment of the present application;

[0044] Figure 5 This is a schematic diagram of the side structure of the second spacer ring in the embodiment of the present application;

[0045] Figure 6 This is a schematic cross-sectional structural diagram of the second spacer ring in the embodiment of the present application;

[0046] Figure 7 This is a schematic diagram of the cross-sectional structure of the shaft core in the embodiment of the present application;

[0047] Figure 8 for Figure 7 A schematic diagram of the enlarged structure of point A in the embodiment;

[0048] Fig. 9 It is a schematic diagram of the partial cross-sectional structure of the electric spindle after assembly in the embodiment of the present application.

[0049] in:

[0050] 100-shaft core; 101-protruding structure; 1011-threaded teeth; 102-first step; 103-second step; 100a-bearing seat installation position; 100b-bearing installation position; 100c-spacer ring assembly installation position;

[0051] 2-bearing seat;

[0052] 300-bearing; 301-front bearing 1; 302-front bearing 2; 303-front bearing inner and outer spacer rings;

[0053] 400-spacer ring assembly; 401-first spacer ring; 4011-first sealing position; 4012-second sealing position; 4013-third sealing position; 402-second spacer ring;

[0054] 500 - sealing section; 501 - first sealing section; 502 - second sealing section; 503 - third sealing section. DETAILED DESCRIPTION

[0055] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0056] Throughout the specification and claims, the following terms have at least the meanings explicitly associated herein, unless the context dictates otherwise. The meanings identified below do not necessarily limit the terms, but merely provide illustrative examples of the terms.

[0057] In the description of the present invention, the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may refer to the same embodiment. Similarly, the phrase "in some embodiments" as used herein, when used multiple times, does not necessarily refer to the same embodiment, although it may refer to the same embodiment. As used herein, the term "or" is an inclusive "or" operator and is equivalent to the term "and / or", unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for additional factors not described, unless the context clearly dictates otherwise. The word "exemplary" means "used as an example, instance or illustration" in this article. Any embodiment described herein as "exemplary" is not necessarily interpreted as being superior or superior to other embodiments. The scope of the present invention is limited only by the scope of the appended claims, and any examples set forth in this specification are not intended to be limiting, but only to set forth some of the many possible embodiments of the claimed invention. The various embodiments provided by the present invention should not be interpreted as limiting the scope of protection of the present invention.

[0058] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0060] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0062] Background

[0063] At present, the preload of the electric spindle bearings is done by adjusting the bearing seat and the bearing to the assembly position before assembly. During the assembly process on the shaft core, the actual situation does not match the theory, so the bearing preload adjustment is performed multiple times, which increases the workload and the preload effect is not good. Therefore, it is particularly important to preload the bearings on the shaft core.

[0064] Based on this, Figure 1-Figure 9 As shown, the first aspect of the embodiment of the present application provides an electric spindle, comprising:

[0065] Axis core 100;

[0066] The bearing seat 200 and the bearing 300 are sleeved on the outer periphery of the shaft core 100 and define an opening facing the axial side of the shaft core 100 with the outer periphery of the shaft core 100. The bearing 300 is sleeved on the outer periphery of the shaft core 100 and placed in the opening; wherein the bearing 300 includes a front bearing 1 301 arranged close to the spacer ring assembly 400, a front bearing 2 302 arranged away from the spacer ring assembly 400, and a front bearing inner and outer spacer rings 303 arranged between the front bearing 1 301 and the front bearing 2 302;

[0067] A spacer ring assembly 400, which is sleeved on the outer periphery of the shaft core 100 and located at the opening side, and is used to axially preload the bearing 300 placed in the bearing seat 200;

[0068] The outer periphery of the shaft core 100 is provided with a protruding structure 101 for interference fit with the inner periphery of the spacer ring assembly 400, and in the axial direction of the shaft core 100, the protruding height of the protruding structure 101 increases from the side away from the bearing 300 to the side close to the bearing 300.

[0069] In the embodiment of the present application, a protrusion structure having a protrusion height that increases from the side away from the bearing 300 to the side close to the bearing 300 is protruded on the outer periphery of the shaft core 100, and the spacer ring assembly 400 and the protrusion structure are set to be interference fit, so that the bearing can be pre-tightened online through the spacer ring assembly sleeved on the shaft core 100, without adjusting the assembly position of the bearing and the bearing seat in advance. After the bearing 300 is pre-tightened outside the shaft core 100, it is prevented from not fitting during the assembly process, thereby reducing the assembly efficiency. Repeated disassembly and assembly process summary is avoided, thereby avoiding increased wear and scratches on high-precision parts.

[0070] Specifically, when pre-tightening the bearing 300, the first spacer ring 401 in the spacer ring assembly 400 can be firstly sleeved on the shaft core, and an axial force is applied to the first spacer ring 401 toward one side of the bearing 300. After the first spacer ring 401 is subjected to the axial force, it moves toward the side of the bearing 300. Since the first spacer ring 401 and the raised structure 101 on the shaft core 100 have an interference fit, and the closer the raised structure 101 is to the bearing, the higher the raised height is, so when the first spacer ring 401 is subjected to the axial force and moves toward the side of the bearing 300, the bearing 300 can also be pre-tightened. 0 applies an axial preload force, thereby realizing online preload of the bearing 300 on the shaft core 100. After the moving position of the first spacer ring 401 is determined {that is, the preload of the bearing 300 has been completed by the movement of the first spacer ring 401}, the second spacer ring 402 can be matched with the first spacer ring 401, and the positioning holes on the second spacer ring 402 and the positioning holes on the bearing seat 200 are matched, and the second spacer ring 402 is fixed to the bearing seat 200 by setting bolts in the positioning holes, thereby realizing fixed installation of the spacer ring assembly.

[0071] Further, in some possible implementations, such as Figure 7 and Figure 8 As shown, the protrusion structure 101 includes a thread structure formed on the outer periphery of the shaft core 100, and the thread structure spirally extends from a side away from the bearing 300 to a side close to the bearing 300;

[0072] The tooth height of the thread teeth 1011 of the thread structure increases from the side away from the bearing 300 to the side close to the bearing 300 .

[0073] In the embodiment of the present application, a threaded structure is provided on the outer periphery of the shaft core 100. On the one hand, the interference fit between the threaded structure and the spacer ring assembly can prevent the spacer ring assembly 400 from being displaced in the axial direction, thereby improving the pre-tightening effect on the bearing 300. On the other hand, by setting the protruding structure as a threaded structure, it can also prevent the spacer ring assembly 400 from causing greater wear to the bearing when mating with the threaded structure.

[0074] Specifically, since the spacer ring assembly 400 can be inserted and pulled out in the axial direction relative to the shaft core 100, when the spacer ring assembly 400 is interference fit with the threaded structure, the outer periphery of the threaded structure is not entirely interference fit with the inner circumference of the spacer ring assembly 400, but only a small section is interference fit with the inner circumference of the spacer ring assembly 400, thereby avoiding the spacer ring assembly 400 from causing greater wear on the threaded structure when it moves relative to the shaft core 100, thereby increasing the service life of the threaded structure, and then increasing the service life of the shaft core 100. That is, in the embodiment of the present application, by setting the protruding structure as a threaded structure, it is possible to achieve an online pre-tightening effect on the bearing and also avoid the problem of reduced service life of the outer periphery of the shaft core 100 due to the provision of the protruding structure.

[0075] Specifically, the thread structure on the outer periphery of the shaft core 100 and the inner circumference of the first spacer ring 401 are installed with a small interference fit, and are tightened according to the interference fit after the position of the bearing 300 is determined.

[0076] It should be noted that the above-mentioned small interference installation means that: the outer diameter of the shaft core 100 is large, and the inner diameter of the first spacer ring 401 is small, but the difference between the outer diameter and the inner diameter is small and will not cause deformation of the two parts.

[0077] Further, in some possible implementations, such as Figure 8 As shown, the thread structure has a plurality of adjacent thread teeth 1011 in the axial direction of the shaft core 100;

[0078] The tooth height difference between two adjacent thread teeth 1011 is within the first tooth height difference range.

[0079] Preferably, Figure 8As shown, considering different specifications when assembling bearings, the tooth height difference e between two adjacent thread teeth 1011 is set between 0.005mm-0.01mm.

[0080] It is to be noted that, in some alternative embodiments, the protrusion structure 101 may also be a plurality of annular protrusions formed on the outer periphery of the shaft core;

[0081] The protrusion heights of the plurality of annular protrusions are gradually increased from a side away from the bearing 300 to a side close to the bearing 300 .

[0082] By configuring the protrusion structure 101 to be a plurality of annular protrusions, it is also possible to achieve the effect of online pre-tightening of the bearing. Although this configuration may result in greater wear between the annular protrusions and the spacer ring assembly 400, correspondingly, greater wear will also increase the pre-tightening effect of the spacer ring assembly 400.

[0083] Further, in any of the above embodiments, if Figure 7 and Figure 8 As shown, the outer periphery of the shaft core 100 is formed with a bearing seat installation position 100a, a bearing installation position 100b and a spacer assembly installation position 100c, and a protruding structure 101 is formed at the spacer assembly installation position 100c;

[0084] A first step 102 is formed between the bearing seat installation position 100a and the bearing installation position 100b, and a second step 103 is formed between the bearing installation position 100b and the spacer assembly installation position 100c;

[0085] The first step 102 is used to axially limit the bearing 300 when the bearing 300 is sleeved on the outer periphery of the shaft core 100, and the second step 103 is used to axially limit the spacer ring assembly 400 when the spacer ring assembly 400 is sleeved on the outer periphery of the shaft core 100.

[0086] Further, in some possible implementations, such as Figure 1-Figure 9 As shown, the spacer ring assembly 400 includes a first spacer ring 401 and a second spacer ring 402 matched in the axial direction of the shaft core 100, the inner circumference of the first spacer ring 401 is used for interference fit with the outer circumference of the shaft core 100, the second spacer ring 402 is fixed on the bearing seat 200, and the inner circumference of the second spacer ring 402 is used for clearance fit with the outer circumference of the first spacer ring 401;

[0087] Among them Fig. 9 As shown, a sealing structure is formed between the first spacer ring 401 and the second spacer ring 402 with clearance fit.

[0088] A sealing structure is formed between the first spacer ring 401 and the second spacer ring 402 in the embodiment of the present application, which can also prevent impurities, cutting fluid and other materials from entering the interior of the bearing 300, thereby ensuring the cleanliness of the interior of the bearing 300 and increasing the service life of the bearing 300.

[0089] Further, in some possible implementations, such as Fig. 9 As shown, the sealing structure includes a sealing segment 500 formed between the mating surfaces of the first spacer ring 401 and the second spacer ring 402, and the sealing segment 500 includes a first sealing segment 501, a second sealing segment 502 and a third sealing segment 503 formed along a sealing path;

[0090] The first sealing section 501 and the third sealing section 503 are labyrinth seals, and the second sealing section 502 is a gap seal.

[0091] A gap seal and a labyrinth seal are formed between the first spacer ring 401 and the second spacer ring 402 in the embodiment of the present application, which can further ensure that impurities, cutting fluid and other materials cannot enter the interior of the bearing, ensure the cleanliness of the interior of the bearing, increase the service life of the bearing, and further improve the sealing effect of the electric spindle.

[0092] Specifically, in some possible implementations, the first spacer ring 401 is sequentially formed with a first sealing position 4011, a second sealing position 4012, and a third sealing position 4013 from a side away from the bearing 300 to a side close to the bearing 300. The first sealing position 4011 cooperates with the second spacer ring 402 to form a first sealing section 501, the second sealing position 4012 cooperates with the second spacer ring 402 to form a second sealing section 502, and the third sealing position 4013 cooperates with the second spacer ring 402 to form a third sealing section 503.

[0093] The first sealing position 4011 includes a first ring tooth that obliquely protrudes along the radial direction of the first spacer ring 401, and the third sealing position 4013 includes a second ring tooth that obliquely protrudes along the axial direction of the first spacer ring 401;

[0094] A dirt storage tank 4014 is formed on the tooth surface of the first ring tooth and / or the tooth surface of the second ring tooth.

[0095] In the embodiment of the present application, by setting the above-mentioned structure for the first spacer ring 401 and the second spacer ring 402, a labyrinth sealing effect and a gap sealing effect can be achieved when the two cooperate. At the same time, in the embodiment of the present application, by setting a dirt storage tank 4014 on the tooth surface of the first ring tooth and / or the tooth surface of the second ring tooth, impurities such as cutting fluid entering into the sealing structure can be collected, which can further prevent impurities from entering the interior of the bearing.

[0096] Further, in some possible implementations, such as Figure 3 and Fig. 9As shown, the first ring teeth obliquely protruding along the radial direction of the shaft core 100 form an angle a with the axial direction of the shaft core 100;

[0097] The second ring teeth obliquely protruding along the axial direction of the shaft core 100 form an angle a1 with the radial direction of the shaft core 100;

[0098] Among them, 45°≤a=a1≤60°.

[0099] In the embodiment of the present application, by setting the angle a and the angle a1 between 45 degrees and 60 degrees and setting the two angles to be the same, on the one hand, the same angle design facilitates the processing of the spacer ring, and on the other hand, by setting the angle between 45 degrees and 60 degrees, the sealing level of this matching position can also be improved.

[0100] Furthermore, in some possible implementations, in order to achieve a better sealing effect with the matched first spacer ring 401 and the second spacer ring 402, as shown in FIG. Figure 2 , Figure 3 and Fig. 9 As shown, the tooth width of the first ring tooth in the axial direction of the shaft core 100 is b, and the tooth height of the first ring tooth in the radial direction of the shaft core 100 is c;

[0101] The tooth width of the second ring tooth in the radial direction of the shaft core 100 is b1, and the tooth height of the second ring tooth in the axial direction of the shaft core 100 is c1;

[0102] Where b and c satisfy: 0.2

[0103] Further, in some possible implementations, such as Fig. 9 As shown, in order to improve the sealing effect while ensuring the stable rotation of the first spacer ring 401 relative to the second spacer ring 402, the clearance fit amount between the first spacer ring 401 and the second spacer ring 402 can be set to h;

[0104] Where h satisfies: 0.3mm <h<0.5mm。

[0105] Furthermore, a second aspect of an embodiment of the present application provides a machine tool, which includes the electric spindle provided in the first aspect of an embodiment of the present application.

[0106] ​In the above-mentioned embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The steps shown in the relevant flow chart can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flow chart, in some cases, the steps shown or described can be executed in an order different from that here. In other words, the order of steps described in the foregoing embodiments is only an example, and it is also within the scope of protection of the embodiments of the present application to reasonably adjust the order of steps based on the content of the embodiments of the present application.

[0107] The sequence of serial numbers or introduction of the embodiments of the present application is for description only and does not represent the superiority or inferiority of the embodiments.

[0108] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0109] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An electric spindle, characterized in that: include: A shaft core (100); A bearing seat (200) and a bearing (300), wherein the bearing seat (200) is sleeved on the outer periphery of the shaft core (100) and defines an opening with the outer periphery of the shaft core (100) facing one axial side of the shaft core (100), and the bearing (300) is sleeved on the outer periphery of the shaft core (100) and placed in the opening; a spacer ring assembly (400), the spacer ring assembly (400) being sleeved on the outer periphery of the shaft core (100) and located on the opening side, and being used for axially pre-tightening the bearing (300) disposed in the bearing seat (200); The outer periphery of the shaft core (100) is provided with a protruding structure (101) for interference fit with the inner periphery of the spacer ring assembly (400), and in the axial direction of the shaft core (100), the protruding height of the protruding structure (101) increases from the side away from the bearing (300) to the side close to the bearing (300).

2. The electric spindle according to claim 1, characterized in that: The protruding structure (101) comprises a thread structure formed on the outer periphery of the shaft core (100), wherein the thread structure spirally extends from a side away from the bearing (300) to a side close to the bearing (300); The tooth height of the thread teeth (1011) of the thread structure increases from a side away from the bearing (300) to a side close to the bearing (300).

3. The electric spindle according to claim 2, characterized in that: The thread structure has a plurality of adjacent thread teeth (1011) in the axial direction of the shaft core (100); The tooth height difference between two adjacent thread teeth (1011) is within a first tooth height difference range.

4. The electric spindle according to claim 3, characterized in that: The tooth height difference between two adjacent thread teeth (1011) is e, wherein 0.005mm<e<0.01mm.

5. The electric spindle according to claim 1, characterized in that: The protrusion structure (101) comprises a plurality of annular protrusions formed on the outer periphery of the shaft core; The protrusion heights of the plurality of annular protrusions are driven to increase progressively from a side away from the bearing (300) to a side close to the bearing (300).

6. The electric spindle according to any one of claims 1 to 5, characterized in that: The outer periphery of the shaft core (100) is formed with a bearing seat installation position (100a), a bearing installation position (100b) and a spacer ring assembly installation position (100c), and the protruding structure (101) is formed at the spacer ring assembly installation position (100c); A first step (102) is formed between the bearing seat installation position (100a) and the bearing installation position (100b), and a second step (103) is formed between the bearing installation position (100b) and the spacer ring assembly installation position (100c); The first step (102) is used to axially limit the bearing (300) when the bearing (300) is sleeved on the outer periphery of the shaft core (100), and the second step (103) is used to axially limit the spacer ring assembly (400) when the spacer ring assembly (400) is sleeved on the outer periphery of the shaft core (100).

7. The electric spindle according to any one of claims 1 to 5, characterized in that: The spacer ring assembly (400) includes a first spacer ring (401) and a second spacer ring (402) that are fitted in the axial direction of the shaft core (100). The inner peripheral surface of the first spacer ring (401) is used for interference fit with the outer periphery of the shaft core (100). The second spacer ring (402) is fixed on the bearing housing (200), and the inner peripheral surface of the second spacer ring (402) is used for clearance fit with the outer peripheral surface of the first spacer ring (401). A sealing structure is formed between the first spacer ring (401) and the second spacer ring (402) with clearance fit.

8. The electric spindle according to claim 7, characterized in that: The sealing structure includes a sealing section (500) formed between the mating surfaces of the first spacer ring (401) and the second spacer ring (402). The sealing section (500) includes a first sealing section (501), a second sealing section (502), and a third sealing section (503) formed along a sealing path. The first sealing section (501) and the third sealing section (503) are labyrinth seals, and the second sealing section (502) is a clearance seal.

9. The electric spindle according to claim 8, characterized in that: The first spacer ring (401) is sequentially formed with a first sealing position (4011), a second sealing position (4012), and a third sealing position (4013) from the side away from the bearing (300) to the side close to the bearing (300). The first sealing position (4011) cooperates with the second spacer ring (402) to form the first sealing section (501), the second sealing position (4012) cooperates with the second spacer ring (402) to form the second sealing section (502), and the third sealing position (4013) cooperates with the second spacer ring (402) to form the third sealing section (503). The first sealing position (4011) includes a first ring tooth that protrudes obliquely in the radial direction of the first spacer ring (401), and the third sealing position (4013) includes a second ring tooth that protrudes obliquely in the axial direction of the first spacer ring (401). A dirt storage groove (4014) is formed on the tooth surface of the first ring tooth and / or the tooth surface of the second ring tooth.

10. The motorized spindle according to claim 9, wherein The first ring tooth that protrudes obliquely in the radial direction of the shaft core (100) forms an angle a with the axial direction of the shaft core (100). The second ring tooth that protrudes obliquely in the axial direction of the shaft core (100) forms an angle a1 with the radial direction of the shaft core (100). Where 45° ≤ a = a1 ≤ 60°.

11. The motorized spindle according to claim 9, wherein The tooth width of the first ring tooth in the axial direction of the shaft core (100) is b, and the tooth height of the first ring tooth in the radial direction of the shaft core (100) is c. The tooth width of the second ring tooth in the radial direction of the shaft core (100) is b1, and the tooth height of the second ring tooth in the axial direction of the shaft core (100) is c1. Where b and c satisfy: 0.2 < b / c < 0.5, and b1 and c1 satisfy: 0.2 < b1 / c1 < 0.

5.

12. The electric spindle according to claim 7, characterized in that: The clearance fit between the first spacer ring (401) and the second spacer ring (402) is h; Where h satisfies: 0.3mm <h<0.5mm。 13. A machine tool, characterized in that: The invention comprises the electric spindle according to any one of claims 1 to 12.

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