CN112792369A

CN112792369A - Electric spindle and machine tool

Info

Publication number: CN112792369A
Application number: CN202110177886.7A
Authority: CN
Inventors: 张翰乾; 伍曦; 张伟江; 黄孙可; 程振涛; 汤秀清
Original assignee: Guangzhou Haozhi Electromechanical Co Ltd
Current assignee: Guangzhou Haozhi Electromechanical Co Ltd
Priority date: 2021-02-09
Filing date: 2021-02-09
Publication date: 2021-05-14
Anticipated expiration: 2041-02-09
Also published as: CN112792369B; WO2022170684A1

Abstract

The invention discloses an electric spindle and a machine tool, comprising: the engine body assembly is provided with an air inlet and a stator; the shaft core assembly is supported on the machine body assembly through an upper bearing assembly and a lower bearing assembly and comprises a shaft core, a rotor, a pull rod assembly and a chuck; the push rod extends into the inner hole of the shaft core from the upper end of the shaft core; the upper bearing assembly comprises an upper bearing seat, an upper bearing and a bearing pre-tightening part, a closed inner cavity is defined in the upper bearing seat, a shaft core inner hole is communicated with the inner cavity, the upper bearing and the bearing pre-tightening part are arranged in the inner cavity, the bearing pre-tightening part is supported between the upper bearing and the upper bearing seat, the upper bearing seat is provided with a piston cavity, the piston cavity is communicated with an air inlet, a floating part is arranged in the piston cavity and abutted against the bearing pre-tightening part, and the shaft core inner hole and/or a pull rod assembly and/or a push rod are/is provided with a spiral structure so that air in the inner cavity is discharged outwards through the shaft core inner hole after the shaft. The invention realizes that the higher the processing rotating speed of the main shaft is, the better the rigidity is.

Description

Electric spindle and machine tool

Technical Field

The invention is used for the field of turning and boring, and particularly relates to an electric spindle and a machine tool.

Background

The electric spindle is one of the most main core components of a numerical control machine tool, and the existing electric spindle has the following defects: 1. the pre-tightening force of the electric main shaft bearing is not adjustable, and the bearing has poor rigidity at high rotating speed; 2. the electric spindle needs to be matched with peripheral equipment such as a water cooler, cutting fluid and the like for cooling, and the occupied area and related cost of the peripheral equipment are high; 3. the existing electric main shaft can not realize the function of spraying cooling liquid when the main shaft runs, and the cost is higher.

Disclosure of Invention

The present invention is directed to solve at least one of the problems of the prior art, and to provide an electric spindle and a machine tool.

The technical scheme adopted by the invention for solving the technical problems is as follows:

in a first aspect, an electric spindle comprises:

the engine body assembly is provided with an air inlet and a stator;

the shaft core assembly is supported on the machine body assembly through an upper bearing assembly and a lower bearing assembly and comprises a shaft core, a rotor, a pull rod assembly and a chuck, and the pull rod assembly and the chuck are arranged in a shaft core inner hole of the shaft core;

the push rod extends into the inner hole of the shaft core from the upper end of the shaft core;

the upper bearing assembly comprises an upper bearing seat, an upper bearing and a bearing pre-tightening component, a closed inner cavity is limited in the upper bearing seat, a shaft core inner hole is communicated with the inner cavity, the upper bearing and the bearing pre-tightening component are arranged in the inner cavity, the bearing pre-tightening component is supported between the upper bearing and the upper bearing seat, a piston cavity is arranged in the upper bearing seat and communicated with the air inlet, a floating component is arranged in the piston cavity and abutted against the bearing pre-tightening component, and the shaft core inner hole and/or a pull rod assembly and/or a push rod are/is provided with a spiral structure so that air in the inner cavity is discharged outwards through the shaft core inner hole after the shaft core assembly rotates.

With reference to the first aspect, in certain implementations of the first aspect, the helical structure includes a first reverse helical groove provided on a wall of the bore of the shaft core.

With reference to the first aspect and the foregoing implementation manners, in certain implementation manners of the first aspect, the pull rod assembly includes a pull rod and a pull rod returning part, and the spiral structure includes a second reverse spiral groove provided on a surface of the pull rod.

With reference to the first aspect and implementations described above, in certain implementations of the first aspect, the helical structure includes a forward spiral groove provided on a surface of the push rod.

With reference to the first aspect and the foregoing implementation manners, in certain implementation manners of the first aspect, the upper bearing seat is provided with an air uniform hole which communicates with the inner cavity which separates the upper bearing.

With reference to the first aspect and the foregoing implementation manners, in certain implementation manners of the first aspect, the machine body assembly is provided with a cutting fluid channel, the cutting fluid channel forms a fluid outlet at the lower end of the electric spindle, the cutting fluid channel flows through a piston cavity of the upper bearing block, the cutting fluid channel forms a first opening for cutting fluid to flow in and a second opening for cutting fluid to flow out on a cavity wall of the piston cavity, a floating component in the piston cavity separates the first opening from the second opening, the floating component is provided with a through hole, and after the shaft core assembly rotates, the floating component floats along the piston cavity to compress the bearing pre-tightening component and is communicated with the first opening and the second opening through the through hole.

With reference to the first aspect and the foregoing implementation manners, in some implementation manners of the first aspect, the method further includes:

the cylinder is connected to the upper end of the machine body assembly through the water jacket component, the output end of the cylinder is connected with the push rod, the water jacket component is provided with an anti-rotation component, and the anti-rotation component is matched with the push rod through a flat position.

With reference to the first aspect and the foregoing implementations, in certain implementations of the first aspect, the gas inlet and the liquid inlet of the cutting fluid passage are both provided to the water jacket member.

With reference to the first aspect and the foregoing implementation manners, in some implementation manners of the first aspect, the lower end of the body component is provided with a protective cover, the protective cover is sleeved on the outer side of the shaft core, an air outlet gap is reserved between the protective cover and the shaft core, the body component is provided with an air path communicated with the air inlet, the air path comprises a first branch and a second branch, the first branch is communicated with the piston cavity, and the second branch is communicated with the protective cover so as to allow air to flow through the air outlet gap to be discharged.

In a second aspect, a machine tool comprises the electric spindle according to any one of the implementations of the first aspect.

One of the above technical solutions has at least one of the following advantages or beneficial effects:

1. after the stator is electrified, the shaft core assembly rotates, the cutter rotates along with the chuck to process, and because the inner hole of the shaft core and/or the pull rod assembly and/or the push rod are/is provided with the spiral structure, air in the main shaft flows from top to bottom, flows out from the edge of the chuck through the chuck, directly faces the surface of a workpiece, blows away scrap iron and the like of the workpiece. Meanwhile, the inside of the chuck is protected, so that scrap iron is not easy to enter the chuck.

2. After the air in the main shaft flows away, the inner cavity of the upper bearing seat generates negative pressure to match with compressed air introduced from the air inlet. The upper end and the lower end of a floating component in the piston cavity generate pressure difference, the pressure difference is larger and larger along with the continuous rising of the rotating speed of the main shaft, and finally the piston cavity moves upwards, so that the compression amount of the bearing pre-tightening component is increased, the pre-tightening force of the bearing is increased, and the rigidity of the bearing is increased. Thus, the higher the processing rotating speed of the main shaft is, the better the rigidity is.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

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

FIG. 1 is a schematic structural diagram of one embodiment of the present invention;

fig. 2 is a schematic cross-sectional view at a-a in fig. 1.

Detailed Description

Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

In the present invention, if directions (up, down, left, right, front, and rear) are described, it is only for convenience of describing the technical solution of the present invention, and it is not intended or implied that the technical features referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, it is not to be construed as limiting the present invention.

In the description of the present invention, if there is description of "first" and "second" only for the purpose of distinguishing technical features, it is not to be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the precedence of the indicated technical features.

In the present invention, unless otherwise specifically limited, the terms "disposed," "mounted," "connected," and the like are to be understood in a broad sense, and for example, may be directly connected or indirectly connected through an intermediate; can be fixedly connected, can also be detachably connected and can also be integrally formed; may be mechanically coupled, may be electrically coupled or may be capable of communicating with each other; either as communication within the two elements or as an interactive relationship of the two elements. The specific meaning of the above-mentioned words in the present invention can be reasonably determined by those skilled in the art in combination with the detailed contents of the technical solutions.

Fig. 1 shows a reference direction coordinate system of an embodiment of the present invention, and the following describes an embodiment of the present invention with reference to the directions shown in fig. 1.

Referring to fig. 1, an embodiment of the present invention provides an electric spindle, which includes a machine body assembly 1, a shaft core assembly 2 and a push rod 3.

Specifically, referring to fig. 1, the engine block assembly 1 is provided with an air inlet 11 and a stator 12, the shaft core assembly 2 is supported on the engine block assembly 1 through an upper bearing assembly 4 and a lower bearing assembly 5, the shaft core assembly 2 comprises a shaft core 21, a rotor 22, a pull rod assembly 24 and a chuck 23, and the pull rod assembly 24 and the chuck 23 are arranged in a shaft core inner hole of the shaft core 21. The stator 12 and the rotor 22 form a motor assembly, the shaft core assembly 2 is driven by the motor assembly to rotate, and the lower end of the shaft core 21 is provided with a chuck 23 which is matched with a pull rod assembly 24 to add a cutter to cut materials.

Referring to fig. 1, the pull rod assembly 24 includes a pull rod 241 and a pull rod returning member 242, and the push rod 3 extends into the inner bore of the spindle 21 from the upper end thereof. When the tool is changed, the push rod 3 can push the pull rod 241 downwards under the driving of external force, and the pull rod 241 drives the chuck 23 to move downwards to release the tool. When the tool of the chuck 23 is replaced, the pull rod resetting component 242 drives the pull rod 241 to reset, and the chuck 23 clamps the tool.

Referring to fig. 1, the upper bearing assembly 4 includes an upper bearing seat 41, an upper bearing 42 and a bearing pre-tightening member 43, and the bearing pre-tightening member 43 may be a disc spring, a compression spring, a reed, or the like. The upper bearing seat 41 internally defines a closed inner cavity 44, the inner hole of the shaft core is communicated with the inner cavity 44, the upper bearings 42 and the bearing pre-tightening components 43 are arranged in the inner cavity 44, one or more upper bearings 42 are arranged, the top of the upper bearings 42 is locked through the bearing nuts 45, the bottom of the upper bearings 42 is pre-tightened through the bearing pre-tightening components 43, and the bearing pre-tightening components 43 are supported between the upper bearings 42 and the upper bearing seat 41. The upper bearing seat 41 is provided with a piston cavity 46, the piston cavity 46 is communicated with the air inlet 11, a floating component 47 is arranged in the piston cavity 46, and the floating component 47 can float in the piston cavity 46 under the action of the pressure difference between the inside and the outside of the inner cavity 44. The floating component 47 is abutted with the bearing pre-tightening component 43, and the floating component 47 compresses or releases the bearing pre-tightening component 43 in the floating process, so that the pre-tightening force of the upper bearing 42 is changed. The spindle bore and/or the drawbar assembly 24 and/or the pushrod 3 is provided with a helical configuration to vent air from the internal cavity 44 outwardly through the spindle bore upon rotation of the spindle assembly 2.

After the stator 12 is electrified, the shaft core assembly 2 rotates, the cutter rotates along with the chuck 23 for processing, and because the inner hole of the shaft core and/or the pull rod assembly 24 and/or the push rod 3 are/is provided with a spiral structure, air in the main shaft flows from top to bottom, passes through the chuck 23, flows out from the edge of the chuck 23, directly faces the surface of a workpiece, and blows away scrap iron and the like of the workpiece. And meanwhile, the inside of the chuck 23 is protected, so that scrap iron is not easy to enter the chuck 23.

After the air in the main shaft flows away, the inner cavity 44 of the upper bearing seat 41 generates negative pressure to match the compressed air introduced from the air inlet 11. The upper end and the lower end of a floating component 47 in the piston cavity 46 generate pressure difference, the pressure difference is larger and larger along with the continuous rising of the rotating speed of the main shaft, and finally the piston cavity 46 moves upwards, so that the compression amount of the bearing pre-tightening component 43 is increased, the pre-tightening force of the bearing is increased, and the rigidity of the bearing is increased. Thus, the higher the processing rotating speed of the main shaft is, the better the rigidity is. The invention realizes the function of adjusting the pretightening force by skillfully designing the structures of the shaft core 21, the pull rod 241, the upper bearing seat 41 and the like.

The helical structure may be a helical groove, a helical tooth, a helical blade, etc., and may be disposed in the inner bore of the shaft core, for example, in some embodiments, referring to fig. 1, the helical structure includes a first reverse helical groove 211 disposed in a wall of the inner bore of the shaft core. When the stator 12 is energized, the spindle assembly 2 rotates, and the tool rotates along with the chuck 23 to perform machining. The rotating first reverse spiral groove 211 drives the air inside the main shaft to flow from top to bottom, pass through the chuck 23, and flow out from the edge of the chuck 23.

A helical structure may also be provided on the surface of the tie rod 241, for example, in some embodiments, referring to fig. 1, the helical structure includes a second reverse helical groove 243 provided on the surface of the tie rod 241, the core assembly 2 is rotated after the stator 12 is energized, and the cutter is rotated along with the rotation of the chuck 23 for machining. The second reverse spiral groove 243 will drive the air in the main shaft to flow from top to bottom, through the chuck 23, and out from the edge of the chuck 23.

The helical structure may also be provided on the surface of the push rod 3, for example in some embodiments, see fig. 1, the helical structure comprises a forward helical groove 31 provided on the surface of the push rod 3. When the spindle rotates anticlockwise, the push rod 3 rotates clockwise relative to the spindle, and the forward spiral groove 31 drives air inside the spindle to flow from top to bottom, pass through the chuck 23, and flow out from the edge of the chuck 23.

In order to ensure that the pressure difference generated by the spiral structure discharging the air flow acts on the floating component 47 in the piston cavity 46 better and the air pressure in the inner cavity 44 is more uniform, see fig. 1, the upper bearing seat 41 is provided with an air uniform hole 411 which is communicated with the inner cavity 44 separated by the upper bearing 42.

In some embodiments, referring to fig. 1, the machine body assembly 1 is provided with a cutting fluid channel 13, the cutting fluid channel 13 forms a fluid outlet 131 at the lower end of the electric spindle, the cutting fluid channel 13 flows through the piston cavity 46 of the upper bearing seat 41, the cutting fluid channel 13 forms a first opening 132 for the cutting fluid to flow in and a second opening 133 for the cutting fluid to flow out on the cavity wall of the piston cavity 46, a floating component 47 in the piston cavity 46 separates the first opening 132 from the second opening 133, the floating component 47 is provided with a through hole 471, and the through hole 471 of the floating component 47 is set according to the orientation of the first opening 132 and the second opening 133 to ensure that the through hole 471 can partially or completely communicate with the first opening 132 and the second opening 133 after the floating component 47 floats a certain distance along the piston cavity 46. For example, in the embodiment shown in fig. 1, the first opening 132 and the second opening 133 are distributed on two sides of the piston chamber 46 in a radial direction, and the through hole 471 of the floating component 47 is opened in a radial direction. The floating component 47 floats up and down, and is controlled by the air pressure difference between the inside and the outside of the piston cavity 46, after the shaft core assembly 2 rotates, the floating component 47 floats along the piston cavity 46 to compress the bearing pre-tightening component 43, and the first opening 132 and the second opening 133 are completely or partially communicated through the through hole 471. In other words, the floating member 47 in the piston chamber 46 performs the function of an automatic control valve of the cutting fluid passage 13, and the control valve is capable of automatically controlling the discharge of the cutting fluid according to the operation state of the main spindle in cooperation with the function of adjusting the bearing preload.

The invention realizes the function that the cutting fluid cools the main shaft and sprays water when the main shaft runs through the ingenious structural design. When the spindle is not operated, the cutting fluid channel 13 is filled with cutting fluid, flows to the floating component 47 in the piston cavity 46 along the cutting fluid channel 13, is blocked by the floating component 47, and the cutting fluid cannot flow continuously. Then, after the main shaft is operated, the floating component 47 moves upwards under the action of the pressure difference, the through hole 471 in the floating component 47 is gradually butted with the first opening 132 and the second opening 133, so that the cutting fluid continuously flows, flows into the machine body assembly 1 again after passing through the upper bearing seat 41, flows out of the main shaft through the fluid outlet 131 at the lower end of the electric main shaft, just sprays to the surface of a machined workpiece, and cools the tool and the workpiece. This has the effect that the cutting fluid is ejected from the spindle only when the spindle is operated. When the main shaft stops, the cutting fluid stops being sprayed out, and the cost is saved. In addition, the electric spindle does not need to be matched with peripheral equipment such as a water cooler, cutting fluid and the like for cooling, and the occupied area and the related cost of the peripheral equipment are saved.

In some embodiments, the electric spindle further comprises a cylinder 6 connected to the upper end of the machine body assembly 1 through a water jacket member 7, and the output end of the cylinder 6 is connected with the push rod 3. When the tool is changed, the cylinder 6 drives the push rod 3 to realize the tool beating.

It can be understood that the push rod 3 can also be driven by a cam or the like to realize the knife striking action.

Referring to fig. 1 and 2, the water jacket member 7 is provided with an anti-rotation member 71, the anti-rotation member 71 is matched with the push rod 3 through a flat position, and the push rod 3 is anti-rotation through the flat position, so that the pull rod 241 is not easy to rotate, and the performance of the spindle is improved.

In some embodiments, in order to facilitate the introduction of an external air source and cutting fluid into the electric spindle, referring to fig. 1, an air inlet 11 and an inlet of a cutting fluid channel 13 are both provided at the water jacket part 7 at the upper end of the spindle.

Referring to fig. 1, the lower bearing assembly 5 includes a lower bearing seat 51 and a lower bearing 52, the lower bearing seat 51 is connected to the lower end of the machine body assembly 1, a protective cover 8 is disposed at the lower end of the machine body assembly 1 on the outer side of the lower bearing seat 51, the protective cover 8 is sleeved on the outer side of the shaft core 21, an air outlet gap 81 is left between the protective cover 8 and the shaft core 21, the machine body assembly 1 is provided with an air passage communicated with the air inlet 11, the air passage includes a first branch 14 and a second branch 15, and the first branch 14 is communicated with the piston cavity 46 and used for ejecting the floating component 47. The second branch 15 is connected to the protecting cover 8 for exhausting the air flowing through the air outlet gap 81. After the air is supplied by the air inlet 11, in addition to one path for ejecting the floating component 47, the other path of air flows out of the main shaft through holes in the machine body, the lower bearing seat 51 and the protective cover 8. The air flow velocity is small because the holes in the machine body, the lower bearing seat 51 and the protective cover 8 are large, the air flow velocity is increased when the air flow passes through the position of the extremely small air outlet gap 81 in the protective cover 8, and the air flow has the convolution characteristic when the shaft core 21 runs at high speed. After the integration, the spiral accelerated airflow is generated, and the front end sealing function is realized.

An embodiment of the invention provides a machine tool, which comprises the electric spindle in any one of the above embodiments. The pretightening force of a main shaft bearing of the machine tool is adjustable, and the front end water spraying and air spraying mode is adopted to replace the traditional cutting fluid processing mode so as to reduce the occupied area and the related cost of peripheral equipment such as a water cooler, the cutting fluid and the like.

In the description herein, references to the description of the term "example," "an embodiment," or "some embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The invention is not limited to the above embodiments, and those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the invention, and such equivalent modifications or substitutions are included in the scope of the claims of the present application.

Claims

1. An electric spindle, comprising:

the engine body assembly is provided with an air inlet and a stator;

2. The electric spindle of claim 1, wherein the helical formation comprises a first reverse helical groove provided in a wall of the bore of the spindle.

3. The motorized spindle of claim 1, wherein the pull rod assembly includes a pull rod and a pull rod return member, and the helical formation includes a second reverse helical groove formed in a surface of the pull rod.

4. The electric spindle of claim 1, wherein the helical structure comprises a positive helical groove provided on the pushrod surface.

5. The electric spindle according to claim 1, wherein the upper bearing seat is provided with a gas homogenizing hole communicating with the inner cavity separating the upper bearing.

6. The electric spindle according to claim 1, wherein the machine body assembly is provided with a cutting fluid channel, the cutting fluid channel forms a fluid outlet at a lower end of the electric spindle, the cutting fluid channel flows through a piston cavity of the upper bearing seat, the cutting fluid channel forms a first opening for the cutting fluid to flow in and a second opening for the cutting fluid to flow out on a cavity wall of the piston cavity, a floating component in the piston cavity separates the first opening and the second opening, the floating component is provided with a through hole, and after the shaft core assembly rotates, the floating component floats along the piston cavity to compress the bearing pre-tightening component and communicate with the first opening and the second opening through the through hole.

7. The electric spindle according to claim 1, further comprising:

8. The electric spindle according to claim 7, wherein the air inlet and the liquid inlet of the cutting fluid passage are both provided in the water jacket member.

9. The motorized spindle of claim 1, wherein the lower end of the housing assembly is provided with a protective cover, the protective cover is fitted on the outer side of the spindle core, an air outlet gap is left between the protective cover and the spindle core, the housing assembly is provided with an air passage communicated with the air inlet, the air passage comprises a first branch and a second branch, the first branch is communicated with the piston cavity, and the second branch is communicated with the protective cover so as to allow air to flow through the air outlet gap and be discharged.

10. A machine tool comprising an electric spindle according to any one of claims 1 to 9.