Shafting pre-tightening structure, electric spindle and machine tool
By using a combination of elastic elements and positioning pistons in the shaft system preload structure of five-axis machine tools, the preload force is provided and the fluid pressure is used to solve the problem of spindle shaft system damage caused by sudden pulling force, achieving high and low speeds and special speeds Stability and accuracy protection under tool use.
Patent Information
- Application Number
- CN202323619683.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2033-12-28
AI Technical Summary
During the reprocessing of five-axis machine tools, the spindle shaft system is damaged due to the sudden pulling force, and the prior art is difficult to effectively protect the spindle, especially when using special tools, it is difficult to deal with the sudden pulling force.
It adopts a shaft system pretension structure, including a bearing seat and a shaft core, and acts on the outer ring of the first bearing in the piston cavity through elastic elements and positioning pistons, providing pretension force to ensure the rigidity of the spindle when running at high and low speeds. And when pull-down tendency, it provides positioning pretension through fluid pressure to avoid damage to the shaft system.
It effectively protects the stability and machining accuracy of the spindle under sudden pulling force, avoids damage to the spindle shaft system, and provides additional positioning and pre-tensioning when using special tools, ensuring the safety and efficiency of the processing process.
Smart Images
Figure CN222268702U_ABST
Abstract
Description
Technical Field
[0001] The utility model is used in the field of processing equipment, in particular to a shaft system pre-tightening structure, an electric spindle and a machine tool. Background Art
[0002] At present, the automotive industry has an increasing demand for five-axis machine tools, and the electric spindle is the core component of the machine tool. Auto parts are becoming more and more complex, and the processing requirements are becoming more and more stringent. The workpiece can complete most or all of the processing procedures in one clamping, thereby improving the processing accuracy of the parts and the processing efficiency of the machine tool. Since most of the work needs to be completed in one clamping, angle heads, T-type milling cutters, and long tool handles are increasingly used, but this type of processing, especially heavy processing, is extremely difficult for the spindle. During the processing process, the sudden downward force will cause damage to the spindle axis. Utility Model Content
[0003] The utility model aims to solve at least one of the technical problems existing in the prior art and provides a shaft system pre-tightening structure, an electric spindle and a machine tool.
[0004] The technical solution adopted by the utility model to solve its technical problems is:
[0005] In a first aspect, a shaft preload structure comprises a bearing seat and a shaft core, the bearing seat is provided with an axial inner hole, the shaft core passes through the axial inner hole and is supported on the bearing seat through a bearing, the bearing comprises a first bearing, the inner ring of the first bearing is assembled on the shaft core, the outer ring of the first bearing is supported on the bearing seat, the bearing seat is provided with a mounting seat on the side of the first bearing close to the shaft end, the mounting seat extends from the bearing seat to the axial inner hole, the mounting seat is provided with an elastic element, the elastic element acts axially on the outer ring of the first bearing, the mounting seat is provided with a piston cavity, a positioning piston is provided in the piston cavity, and the positioning piston can act axially on the outer ring of the first bearing under the action of the fluid in the piston cavity.
[0006] In combination with the first aspect, in certain implementations of the first aspect, the mounting seat extends circumferentially along the axial inner hole, an annular protrusion structure is formed in the axial inner hole, a radial gap is left between the mounting seat and the shaft core, and a plurality of the elastic elements are provided along the mounting seat.
[0007] In combination with the first aspect and the above-mentioned implementations, in certain implementations of the first aspect, the mounting seat is provided with an annular groove on the end surface facing the first bearing, and the piston cavity is formed by the annular groove, and the positioning piston is annular and assembled in the piston cavity.
[0008] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, a bearing sleeve is provided between the first bearing and the bearing seat, the outer ring of the first bearing is supported by the bearing sleeve, the bearing sleeve is provided with a supporting edge for axially supporting the outer ring of the first bearing, and the elastic element abuts between the supporting edge and the mounting seat.
[0009] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, the mounting seat is provided with a limit cover, the limit cover extends to the outside of the annular groove, and the positioning piston is provided with a limit step that cooperates with the limit cover, and when the limit step abuts against the limit cover, the positioning piston and the bearing sleeve have an interference fit.
[0010] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, an axial mounting hole is provided on the end surface of the bearing sleeve, and the elastic element includes a spring arranged in the axial mounting hole.
[0011] In combination with the first aspect and the above-mentioned implementations, in certain implementations of the first aspect, the bearing includes a second bearing, the second bearing is closer to the end of the shaft system than the first bearing, the inner ring of the second bearing is assembled on the shaft core, and the outer ring of the second bearing is supported on the bearing seat.
[0012] In combination with the first aspect and the above-mentioned implementations, in certain implementations of the first aspect, an inner spacer sleeve is provided between the inner ring of the second bearing and the inner ring of the first bearing, and the mounting seat is axially abutted against the outer ring of the second bearing at the end face on the side facing away from the first bearing.
[0013] In a second aspect, an electric spindle includes the shaft pre-tightening structure described in any implementation of the first aspect.
[0014] In a third aspect, a machine tool comprises the electric spindle described in any implementation of the second aspect.
[0015] One of the above technical solutions has at least one of the following advantages or beneficial effects: In the technical solution of the utility model, under the use condition of the shaft core connected to the normal tool handle, there is no pressure in the piston cavity, and the preload force of the shaft system bearing is preloaded by the elastic element to the first bearing, ensuring the high and low speed operation of the main shaft and a certain rigidity. However, when using special tools, that is, when there is a tendency of the shaft system to pull down, the shaft system becomes a loaded working state. At this time, the positioning piston acts axially on the outer ring of the first bearing under the action of the fluid in the piston cavity. When there is a tendency to pull down, due to the presence of a certain fluid pressure in the piston cavity, the pressure on the side of the positioning piston cavity is extremely large, which can be approximated as positioning preload, thereby avoiding damage to the main shaft system due to sudden downward pulling force during the processing.
[0016] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:
[0018] Figure 1 This is a schematic structural diagram of an embodiment of the electric spindle of the utility model in the first working state;
[0019] Figure 2 yes Figure 1 The structure diagram of an embodiment shown is in the second working state. DETAILED DESCRIPTION
[0020] This section will describe in detail the specific embodiments of the utility model. The preferred embodiments of the utility model are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the utility model, but it cannot be understood as a limitation on the protection scope of the utility model.
[0021] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.
[0022] In the present utility model, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present utility model, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0023] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.
[0024] See also Figure 1 , Figure 2 An embodiment of the utility model provides a shaft preload structure, including a bearing seat 100 and a shaft core 200. The bearing seat 100 is provided with an axial inner hole 101. The shaft core 200 passes through the axial inner hole 101 and is supported on the bearing seat 100 by a bearing to form a shaft structure. The shaft core 200 can be connected to a tool handle at the end of the shaft structure for processing.
[0025] Among them, the bearing includes a first bearing 301, and one or more first bearings 301 can be set. The inner ring of the first bearing 301 is assembled on the shaft core 200, and the outer ring of the first bearing 301 is supported on the bearing seat 100. The bearing seat 100 is provided with a mounting seat 102 on the side of the first bearing 301 close to the shaft end 601. The mounting seat 102 extends from the bearing seat 100 to the axial inner hole 101. The mounting seat 102 is provided with an elastic element 103, and the elastic element 103 acts on the outer ring of the first bearing 301 in the axial direction. The mounting seat 102 is provided with a piston cavity 104, and a positioning piston 105 is provided in the piston cavity 104. The positioning piston 105 can act on the outer ring of the first bearing 301 in the axial direction under the action of the fluid in the piston cavity 104.
[0026] In the technical solution of the present utility model, under the condition that the shaft core 200 is connected to the normal tool handle, see Figure 1 There is no pressure in the piston chamber 104, and the shaft bearing preload is applied by the elastic element 103 to the first bearing 301, ensuring the high and low speed operation of the spindle and a certain rigidity. However, when using special tools, that is, when there is a tendency for the shaft system to pull down, the shaft system becomes a loaded working state, see Figure 2 At this time, the positioning piston 105 acts axially on the outer ring of the first bearing 301 under the action of the fluid in the piston chamber 104. When a downward pull-down trend occurs, due to the presence of a certain fluid pressure in the piston chamber 104, the pressure on the cavity side of the positioning piston 105 is extremely large, which can be approximated as positioning pre-tightening, thereby avoiding damage to the spindle shaft system due to sudden downward pull-down force during the machining process.
[0027] In some embodiments, see Figure 1 , Figure 2 The mounting seat 102 extends along the circumference of the axial inner hole 101, and an annular protrusion structure is formed in the axial inner hole 101. The mounting seat 102 is terminated before extending to the shaft core 200. A radial gap is left between the mounting seat 102 and the shaft core 200, and a plurality of elastic elements 103 are arranged along the circumference of the mounting seat 102. In this embodiment, the axial preload force of the first bearing 301 can be adjusted by adjusting the number of elastic elements 103. At the same time, the mounting seat 102 with an annular protrusion structure can be obtained by a rotary processing method, so that it is more convenient to process and manufacture on the bearing seat 100, and the processing accuracy is guaranteed.
[0028] For further information, see Figure 1 , Figure 2 The mounting seat 102 is provided with an annular groove on the end surface of one side facing the first bearing 301, and a piston cavity 104 is formed by the annular groove. The positioning piston 105 is annular and assembled in the piston cavity 104. In this embodiment, when an axial preload is required to be applied to the outer ring of the first bearing 301, the bearing seat 100 is provided with a fluid channel 108 connected with the annular groove, and a pressure fluid can be injected into the piston cavity 104 through the fluid channel. The positioning piston 105 moves axially in the annular groove and acts on the outer ring of the first bearing 301. Since the positioning piston 105 is annular, a uniform axial preload can be provided for the outer ring of the first bearing 301.
[0029] The axial preload force of the elastic element 103 and / or the positioning piston 105 may act directly or indirectly on the outer ring of the first bearing 301. In some embodiments, see Figure 1 , Figure 2 A bearing sleeve 400 is provided between the first bearing 301 and the bearing seat 100, the outer ring of the first bearing 301 is supported by the bearing sleeve 400, the bearing sleeve 400 is provided with a support edge 401 for supporting the outer ring of the first bearing 301 in the axial direction, and the elastic element 103 is abutted between the support edge 401 and the mounting seat 102. In this embodiment, the first bearing 301 is assembled to the axial inner hole 101 of the bearing seat 100 through the bearing sleeve 400, the first bearing 301 is more convenient to assemble, and the axial preload effect is better.
[0030] In some embodiments, see Figure 1 , Figure 2 The mounting seat 102 is provided with a limit cover 106, which extends to the outside of the annular groove, and the positioning piston 105 is provided with a limit step 107 that cooperates with the limit cover 106. When the limit step 107 abuts against the limit cover 106, the positioning piston 105 and the bearing sleeve 400 are interference fit. In this embodiment, the limit cover 106 is used to limit the axial stroke of the positioning piston 105 to prevent the bearing from being damaged by excessive fluid pressure. At the same time, it is ensured that when using special tools, that is, when there is a tendency for the shaft system to pull down, the positioning piston 105 can provide positioning preload for the first bearing 301.
[0031] In some embodiments, see Figure 1 , Figure 2 In order to facilitate the assembly of the elastic element 103, an axial mounting hole is provided on the end surface of the bearing sleeve 400, and the elastic element 103 includes a spring arranged in the axial mounting hole.
[0032] In some embodiments, see Figure 1 , Figure 2The bearing further includes a second bearing 500, which is located outside the first bearing 301 in the axial direction, and is closer to the end of the shaft system than the first bearing 301. The inner ring of the second bearing 500 is assembled on the shaft core 200, and the outer ring of the second bearing 500 is supported on the bearing seat 100. In other words, the shaft core 200 is supported on the bearing seat 100 through the first bearing 301 and the second bearing 500 on both sides of the mounting seat 102, so as to improve the stability and rotation accuracy of the end of the shaft core 200.
[0033] For further information, see Figure 1 , Figure 2 An inner spacer 501 is provided between the inner ring of the second bearing 500 and the inner ring of the first bearing 301 , and the mounting seat 102 is axially abutted against the outer ring of the second bearing 500 at the end surface on the side away from the first bearing 301 .
[0034] The existing shaft preload adjustment method directly increases the preload force to provide rigidity, but this is still limited to processing with sudden pull-down forces, because the applied load must be within the acceptable range of the bearing. If it is too large or too small, it cannot protect the shaft system. At the same time, the bearing always bears unnecessary processing loads. In addition, there is a rigidity problem of the elastic element itself, that is, the stiffness of the elastic element is much smaller than the rigidity of the bearing. The automatic adjustment preload method is also unable to cope with sudden loads. The embodiment of the utility model realizes the switching between positioning preload and constant pressure preload, thereby protecting the shaft system from friction between the shaft system and other parts caused by the pull-down force.
[0035] An embodiment of the utility model further provides an electric spindle 600, comprising the shaft system pre-tightening structure in any of the above embodiments.
[0036] An embodiment of the utility model further provides a machine tool, comprising the electric spindle 600 in any one of the above embodiments.
[0037] In the description of this specification, the description with reference to the terms "example", "embodiment" or "some embodiments" 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 utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0038] Of course, the invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the invention, and these equivalent modifications or substitutions are all included in the scope defined by the claims of this application.
Claims
1. A shaft pre-tightening structure, characterized in that: The invention comprises a bearing seat and an axis core, wherein the bearing seat is provided with an axial inner hole, the axis core passes through the axial inner hole and is supported on the bearing seat through a bearing, the bearing comprises a first bearing, the inner ring of the first bearing is assembled on the axis core, the outer ring of the first bearing is supported on the bearing seat, the bearing seat is provided with a mounting seat on a side of the first bearing close to the end of the shaft system, the mounting seat extends from the bearing seat to the axial inner hole, the mounting seat is provided with an elastic element, the elastic element acts on the outer ring of the first bearing in the axial direction, the mounting seat is provided with a piston cavity, a positioning piston is provided in the piston cavity, and the positioning piston can act on the outer ring of the first bearing in the axial direction under the action of the fluid in the piston cavity.
2. The shafting pre-tightening structure according to claim 1, characterized in that: The mounting seat extends along the circumference of the axial inner hole, and an annular protrusion structure is formed in the axial inner hole. A radial gap is left between the mounting seat and the shaft core, and a plurality of the elastic elements are arranged along the mounting seat.
3. The shafting pre-tightening structure according to claim 2, characterized in that: The mounting seat is provided with an annular groove on one end surface facing the first bearing, and the piston cavity is formed by the annular groove. The positioning piston is annular and assembled in the piston cavity.
4. The shafting pre-tightening structure according to claim 3, characterized in that: A bearing sleeve is provided between the first bearing and the bearing seat, the outer ring of the first bearing is supported by the bearing sleeve, the bearing sleeve is provided with a supporting edge for axially supporting the outer ring of the first bearing, and the elastic element abuts between the supporting edge and the mounting seat.
5. The shafting pre-tightening structure according to claim 4, characterized in that: The mounting seat is provided with a limit cover, which extends to the outside of the annular groove. The positioning piston is provided with a limit step that cooperates with the limit cover. When the limit step abuts against the limit cover, the positioning piston and the bearing sleeve are interference fit.
6. The shafting pre-tightening structure according to claim 4, characterized in that: An axial mounting hole is arranged on the end surface of the bearing sleeve, and the elastic element comprises a spring arranged in the axial mounting hole.
7. The shafting pre-tightening structure according to claim 1, characterized in that: The bearing includes a second bearing, which is closer to the end of the shaft system than the first bearing. The inner ring of the second bearing is assembled on the shaft core, and the outer ring of the second bearing is supported on the bearing seat.
8. The shafting pre-tightening structure according to claim 7, characterized in that: An inner spacer sleeve is provided between the inner ring of the second bearing and the inner ring of the first bearing, and the mounting seat is axially abutted against the outer ring of the second bearing at an end surface on a side away from the first bearing.
9. An electric spindle, characterized in that: The invention comprises the shafting pre-tightening structure according to any one of claims 1 to 8.
10. A machine tool, characterized in that: Includes the electric spindle as claimed in claim 9.