Main shaft cooling structure, main shaft and machine tool

Abstract

The main shaft cooling structure comprises a machine body, the machine body is provided with a shaft core mounting hole extending in the axial direction, the machine body is provided with a first bearing seat and a second bearing seat along the shaft core mounting hole, and the machine body is provided with a stator cooling water jacket between the first bearing seat and the second bearing seat. The main shaft cooling structure comprises a first cooling water channel and a second cooling water channel, the first cooling water channel flows through the first bearing seat, the stator cooling water jacket and the second bearing seat, the second cooling water channel flows through the first bearing seat, the stator cooling water jacket and the second bearing seat, and the first cooling water channel is separated from the second cooling water channel. The cooling water of each pipe flows in an independent cooling flow channel and independently flows through the first bearing seat, the stator cooling water jacket and the second bearing seat to cool the bearing and the motor, and the structure has the advantages of being high in cooling efficiency, high in flow speed and low in pressure loss. And various machining problems caused by short service life of the bearing and large thermal elongation of the shaft core due to poor cooling of the main shaft can be effectively solved.

Description

Technical Field

[0001] The utility model is used in the field of spindles, and particularly relates to a spindle cooling structure, a spindle and a machine tool. Background Technique

[0002] The motorized spindle is widely used in various machine tools because of its advantages of convenient installation, compact structure, light weight, small vibration, high rotational speed, high machining accuracy and stable machining effect. As the core functional component of the machine tool, the performance index and service life of the spindle directly affect the machining performance of the machine tool and the MTBF.

[0003] From the empirical data, the abnormal points of the spindle are basically concentrated in the abnormal bearing life. Excluding the rapid bearing damage caused by accidental factors such as machine collision and overload during the use of the spindle, the remaining bearing abnormalities are mainly concentrated in the problems such as grease loss and deterioration caused by long-term high-speed operation of the bearing and poor cooling, resulting in the failure of the lubricating oil film and problems such as bearing raceway pitting, spalling and burning. Therefore, the reasonable cooling of the bearing is crucial for the service life of the bearing.

[0004] The quality of spindle cooling not only affects the service life of the bearing, but also causes a high thermal equilibrium temperature of the spindle, resulting in a large thermal deformation of the spindle core. The large thermal deformation of the spindle core will cause problems such as plane concavity, dimensional changes and tool joint marks during the long-cycle machining process, which is an important factor restricting the machining accuracy of the machine tool size, especially obvious in high-end machine tools.

[0005] At present, the common cooling water channels of the spindle mainly include the following several types: ① upper and lower water channels (axial cooling holes are directly opened in the body); ② spiral water channels (spiral water grooves are opened in the body and the bearing seat). Due to the unreasonable structural design of the existing cooling water channel solutions, various machining problems are caused by insufficient bearing life and large thermal elongation of the spindle core due to poor cooling. Content of the Utility Model

[0006] The purpose of the utility model is to solve at least one of the technical problems existing in the prior art, and to provide a spindle cooling structure, a spindle and a machine tool.

[0007] The technical solution adopted by the utility model to solve its technical problems is:

[0008] In a first aspect, a spindle cooling structure includes a body. The body is provided with a core mounting hole extending axially. The body is provided with a first bearing seat and a second bearing seat along the core mounting hole. The body is provided with a stator cooling water jacket between the first bearing seat and the second bearing seat. The spindle cooling structure includes a first cooling water channel and a second cooling water channel. The first cooling water channel flows through the first bearing seat, the stator cooling water jacket and the second bearing seat. The second cooling water channel flows through the first bearing seat, the stator cooling water jacket and the second bearing seat. The first cooling water channel and the second cooling water channel are spaced apart from each other.

[0009] Combined with the first aspect, in some implementation manners of the first aspect, the first bearing seat is located at the front end of the body, the second bearing seat is located at the rear end of the body. The first cooling water channel sequentially flows through the first bearing seat, the stator cooling water jacket and the second bearing seat. The second cooling water channel sequentially flows through the first bearing seat, the stator cooling water jacket and the second bearing seat.

[0010] Combined with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the first bearing seat is integrally formed at the front end of the body. The outer wall surface of the first bearing seat is provided with a first ring groove and a second ring groove. The first ring groove and the second ring groove are spaced apart from each other. An outer casing of the body is sleeved outside the first bearing seat. The outer casing of the body shields the first ring groove and the second ring groove. The first cooling water channel extends along the body to the first ring groove and circulates along the first ring groove and then enters the stator cooling water jacket. The second cooling water channel extends along the body to the second ring groove and circulates along the second ring groove and then enters the stator cooling water jacket.

[0011] Combined with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the outer wall surface of the stator cooling water jacket is provided with a first water jacket water channel and a second water jacket water channel. The first water jacket water channel and the second water jacket water channel are spaced apart from each other. The body is sleeved on the outer wall surface of the stator cooling water jacket and shields the first water jacket water channel and the second water jacket water channel. The first cooling water channel flows into the first water jacket water channel after flowing through the first bearing seat. The second cooling water channel flows into the second water jacket water channel after flowing through the first bearing seat.

[0012] Combined with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the outer wall surface of the stator cooling water jacket includes a left outer wall surface and a right outer wall surface which are arranged in a mirror image. The first water jacket water channel is arranged in an S shape on the left outer wall surface, and the second water jacket water channel is arranged in an S shape on the right outer wall surface. The first water jacket water channel forms an inlet at one end close to the first bearing seat and forms an outlet at one end close to the second bearing seat. The second water jacket water channel forms an inlet at one end close to the first bearing seat and forms an outlet at one end close to the second bearing seat.

[0013] Combined with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the outer periphery of the second bearing seat is provided with a third annular groove and a fourth annular groove which are separated from each other. The first cooling water channel accesses the third annular groove after flowing through the stator cooling water jacket, circulates along the third annular groove and then flows out. The second cooling water channel accesses the fourth annular groove after flowing through the stator cooling water jacket, circulates along the fourth annular groove and then flows out.

[0014] Combined with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the first cooling water channel and the second cooling water channel are provided with water inlets and water outlets on the second bearing seat.

[0015] Combined with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the second bearing seat is separately provided from the machine body. The outer wall surface of the second bearing seat is provided with a third annular groove and a fourth annular groove. The second bearing seat is embedded in the rear end of the machine body, and the machine body shields the third annular groove and the fourth annular groove.

[0016] In a second aspect, a main shaft includes the main shaft cooling structure according to any one of the implementation manners in the first aspect.

[0017] In a third aspect, a machine tool includes the main shaft according to any one of the implementation manners in the second aspect.

[0018] At least one of the technical solutions in the above technical solutions has the following advantages or beneficial effects: In the technical solution of the present utility model, the main shaft cooling structure adopts a double-channel cooling method, that is, a first cooling water channel and a second cooling water channel. The first cooling water channel and the second cooling water channel are completely separated. Each pipe of cooling water flows in a separate cooling flow channel, and independently flows through the first bearing seat, the stator cooling water jacket and the second bearing seat, and then completes the cooling of the bearing and the motor. This structure has the characteristics of high cooling efficiency, fast flow rate and low pressure loss. It can effectively improve various processing problems caused by insufficient bearing life due to poor cooling of the main shaft and long thermal elongation of the shaft core.

[0019] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present utility model. Description of the Drawings

[0020] The above and / or additional aspects and advantages of the present utility model will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1 is a schematic structural view of an embodiment of the spindle cooling structure of the present utility model;

[0022] Figure 2 is Figure 1 a schematic structural view of an embodiment of the machine body shown;

[0023] Figure 3 is Figure 1 a schematic structural view of an embodiment of the outer casing of the machine body shown;

[0024] Figure 4 is Figure 1 an axonometric view of an embodiment of the stator cooling water jacket structure of the machine body shown;

[0025] Figure 5 is Figure 1 a front view of an embodiment of the stator cooling water jacket structure of the machine body shown;

[0026] Figure 6 is Figure 1 a schematic structural view of an embodiment of the second bearing seat shown;

[0027] Figure 7 is Figure 1 a schematic view of an embodiment of the rear end shown;

[0028] Figure 8 is Figure 7 a sectional view taken along line A-A in ;

[0029] Figure 9 is Figure 7 a sectional view taken along line B-B in ;

[0030] Figure 10 is Figure 7 a sectional view taken along line C-C in ;

[0031] Figure 11 is Figure 7 a sectional view taken along line D-D in. Detailed Embodiments

[0032] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the drawings. The function of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present utility model. However, it should not be construed as a limitation on the protection scope of the present utility model.

[0033] In the present utility model, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of the present utility model, rather than indicating or implying that the technical features referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the present utility model.

[0034] In the present utility model, the meaning of "several" is one or more, the meaning of "multiple" is two or more, and "greater than", "less than", "exceeding", etc. are understood not to include the present number; "above", "below", "within", etc. are understood to include the present number. In the description of the present utility model, if "first" and "second" are described, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or the sequence relationship of the indicated technical features.

[0035] In the present utility model, unless otherwise clearly defined, terms such as "set", "installed", "connected", etc. 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 capable of communicating with each other; they can be the communication inside two components or the interaction relationship between two components. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present utility model in combination with the specific content of the technical solution.

[0036] Among them, Figure 1 and Figure 4 give the reference direction coordinate system of the embodiments of the present utility model. The following will describe the embodiments of the present utility model in combination with Figure 1 and Figure 4 the directions shown.

[0037] The main criteria for measuring the quality of the cooling water channel design are the cooling hydraulic loss and the temperature of the core parts after cooling under the condition of the same coolant flow rate. The pressure loss is related to the cross-sectional size, path length, and inflection point structure design; the temperature of the core parts after cooling is related to the contact area (heat exchange area) between the coolant and the water channel.

[0038] To improve the cooling capacity of the existing water channel and thus enhance the machining performance and service life of the spindle and the machine tool, an embodiment of the present utility model provides a spindle cooling structure, which features high cooling efficiency, fast flow rate, and low pressure loss. It can effectively improve the problems of insufficient bearing life caused by poor cooling of the spindle and various machining problems caused by large thermal elongation of the shaft core.

[0039] See Figure 1 、 Figure 8 , the spindle cooling structure includes a body 100. The body 100 is provided with a core mounting hole 101 extending along the axial direction. The body 100 is provided with a first bearing seat 200 and a second bearing seat 300 along the core mounting hole 101. The spindle core can be rotatably mounted in the core mounting hole 101 through bearings provided in the first bearing seat 200 and the second bearing seat 300. The body 100 is provided with a stator cooling water jacket 400 between the first bearing seat 200 and the second bearing seat 300. The stator cooling water jacket 400 corresponds to the stator outside the spindle core and is used to cool the stator of the spindle. The spindle cooling structure includes a first cooling water channel 500 and a second cooling water channel 600. The first cooling water channel 500 flows through the first bearing seat 200, the stator cooling water jacket 400, and the second bearing seat 300. The second cooling water channel 600 flows through the first bearing seat 200, the stator cooling water jacket 400, and the second bearing seat 300. The first cooling water channel 500 and the second cooling water channel 600 are separated from each other.

[0040] In the technical solution of the present utility model, the spindle cooling structure adopts a double-channel cooling method, that is, the first cooling water channel 500 and the second cooling water channel 600. The first cooling water channel 500 and the second cooling water channel 600 are completely separated. Each pipe of cooling water flows in a separate cooling flow path and independently flows through the first bearing seat 200, the stator cooling water jacket 400, and the second bearing seat 300, and then completes the cooling of the bearing and the motor. This structure features high cooling efficiency, fast flow rate, and low pressure loss. It can effectively improve the problems of insufficient bearing life caused by poor cooling of the spindle and various machining problems caused by large thermal elongation of the shaft core.

[0041] See Figure 1 、 Figures 8 - 11, the first bearing housing 200 is located at the front end of the machine body 100, the second bearing housing 300 is located at the rear end of the machine body 100, the first cooling water channel 500 flows through the first bearing housing 200, the stator cooling water jacket 400 and the second bearing housing 300 in sequence, and the second cooling water channel 600 flows through the first bearing housing 200, the stator cooling water jacket 400 and the second bearing housing 300 in sequence. In the embodiment of the present utility model, the first bearing housing 200 is cooled first, then the stator cooling water jacket 400 is cooled, and finally the second bearing housing 300 is cooled. Among them, cooling the front bearing first helps to ensure that the temperature at the lower end of the main shaft is the lowest, the thermal elongation of the shaft core is the smallest, and the temperature of the bearing grease is at a lower temperature, so that it can be loaded and run at high speed for a long time. After cooling the first bearing housing 200, it then flows through the stator cooling water jacket 400 to complete the cooling of the entire motor of the main shaft. The advantage of this cooling method is to ensure that the temperature of the main shaft box in contact with the main shaft body 100 is at a lower state as much as possible. Especially, the machine body 100 near the flange is in direct contact with the main shaft box, avoiding the transfer of temperature to the main shaft box due to the too high temperature of the main shaft. The main shaft box is huge. Under the condition of a certain coefficient of thermal expansion, the larger the volume, the higher the temperature rise and the greater the thermal elongation. Therefore, the main shaft box is extremely sensitive to the size and stability of the heat source. The rear bearing is a floating end, the bearing is not stressed, and the bearing size is smaller than that of the lower bearing end. Since the bearing DN value is fixed, the smaller the bearing diameter size D, the larger the limiting speed N can be, and the higher the limiting speed. At the same rotational speed, the smaller the bearing size, the less heat the bearing generates, the lower the temperature of the bearing grease, and the longer the bearing life. Therefore, cooling the rear bearing last will not affect the service life of the main shaft.

[0042] In some embodiments, referring to Figure 1 , Figure 2 , Figure 3 , the first bearing housing 200 is integrally formed at the front end of the machine body 100. The outer wall surface of the first bearing housing 200 is provided with a first annular groove 201 and a second annular groove 202. The first annular groove 201 and the second annular groove 202 are separated from each other. An outer casing 700 of the machine body is sleeved outside the first bearing housing 200. The outer casing 700 of the machine body shields the first annular groove 201 and the second annular groove 202. The first cooling water channel 500 extends along the machine body 100 to the first annular groove 201, and after circulating along the first annular groove 201, it enters the stator cooling water jacket 400. The second cooling water channel 600 extends along the machine body 100 to the second annular groove 202, and after circulating along the second annular groove 202, it enters the stator cooling water jacket 400.

[0043] Referring to Figure 8 , Figure 9 , the coolant enters from two cooling channels (the first cooling water channel 500 and the second cooling water channel 600), flows through the machine body 100 and the outer casing 700 of the machine body and enters the front end of the machine body 100. There are two non-connected water tanks (the first annular groove 201 and the second annular groove 202) at the front end of the machine body 100. The water inlet of the water tank circulates 180°, and flows out from the opposite water outlet hole to complete the cooling of the front bearing.

[0044] In some embodiments, referring to Figure 1 and Figure 9 , on the outer wall surface of the stator cooling water jacket 400, a first water jacket water channel 401 and a second water jacket water channel 402 are provided. The first water jacket water channel 401 and the second water jacket water channel 402 are separated from each other. The body 100 is sleeved on the outer wall surface of the stator cooling water jacket 400 and shields the first water jacket water channel 401 and the second water jacket water channel 402. The first cooling water channel 500 flows through the first bearing block 200 and then flows into the first water jacket water channel 401, and the second cooling water channel 600 flows through the first bearing block 200 and then flows into the second water jacket water channel 402. The first water jacket water channel 401 and the second water jacket water channel 402 can be arranged in a spiral shape or other shapes.

[0045] Specifically, referring to Figure 4 and Figure 5 , the outer wall surface of the stator cooling water jacket 400 includes a left outer wall surface and a right outer wall surface which are mirror-image arranged. The first water jacket water channel 401 is arranged in an S shape on the left outer wall surface, and the second water jacket water channel 402 is arranged in an S shape on the right outer wall surface. The first water jacket water channel 401 forms an inlet at one end close to the first bearing block 200 and forms an outlet at one end close to the second bearing block 300. The second water jacket water channel 402 forms an inlet at one end close to the first bearing block 200 and forms an outlet at one end close to the second bearing block 300. The coolant flowing out from the front end of the body 100 enters the lower end of the stator cooling water jacket 400 in two pipes. The stator cooling water jacket 400 is provided with completely separated cooling areas. The stator cooling water jacket 400 circulates to the upper end, completing the cooling of the entire main shaft motor and taking away the heat of the motor. In this embodiment, the cross-sections of the first water jacket water channel 401 and the second cold water channel are larger, and the inflection point structure design is better; the contact area (heat exchange area) between the coolant and the water channel is larger, having a better cooling effect.

[0046] In some embodiments, referring to Figure 1 , on the outer periphery of the second bearing block 300, a third ring groove 301 and a fourth ring groove 302 are provided. The third ring groove 301 and the fourth ring groove 302 are separated from each other. The first cooling water channel 500 flows through the stator cooling water jacket 400 and then is connected to the third ring groove 301 and circulates along the third ring groove 301 and then flows out. The second cooling water channel 600 flows through the stator cooling water jacket 400 and then is connected to the fourth ring groove 302 and circulates along the fourth ring groove 302 and then flows out.

[0047] Referring to Figure 10 and Figure 11 , the coolant flowing out from the upper end of the stator cooling water jacket 400 enters the two water tanks of the second bearing block 300 in two pipes, and the two water tanks are not connected to each other (the third ring groove 301 and the fourth ring groove 302). The water inlet of the water tank circulates 180°, and flows out from the opposite water outlet hole, thereby completing the cooling of the upper bearing.

[0048] Among them, referring to Figure 7 , the first cooling water channel 500 and the second cooling water channel 600 are provided with water inlets 501, 601 and water outlets 502, 602 in the second bearing housing 300.

[0049] In some embodiments, referring to Figure 1 、 Figure 6 , the second bearing housing 300 is separately provided from the machine body 100. The outer wall surface of the second bearing housing 300 is provided with a third annular groove 301 and a fourth annular groove 302. The second bearing housing 300 is embedded in the rear end of the machine body 100, and the machine body 100 shields the third annular groove 301 and the fourth annular groove 302.

[0050] The embodiments of the present utility model can effectively reduce the bearing temperature, extend the service life of the main shaft, simultaneously reduce the thermal elongation of the main shaft, and improve the machining stability and accuracy of the machine tool. Through simulation calculation, the double-channel cooling structure has a significant improvement in cooling effect compared with the single-channel spiral structure. The temperature rise of the lower bearing is reduced by 23%, the temperature rise of the stator and the surface of the machine body 100 is reduced by 19%, and the pressure loss at the coolant inlet and outlet is reduced by 37%. The cooling effect is good.

[0051] The embodiments of the present utility model also provide a main shaft, including the main shaft cooling structure in any one of the above embodiments.

[0052] The embodiments of the present utility model also provide a machine tool, including the main shaft in any one of the above embodiments.

[0053] In the description of this specification, the descriptions referring to terms such as "example", "embodiment" or "some embodiments" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. 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 can be combined in a suitable manner in any one or more embodiments or examples.

[0054] Certainly, the present invention is not limited to the above embodiments. Those skilled in the art can make equivalent deformations or substitutions without departing from the spirit of the present utility model, and these equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A spindle cooling structure, characterized in that: The invention comprises a machine body, wherein the machine body is provided with an axial core mounting hole extending in an axial direction, the machine body is provided with a first bearing seat and a second bearing seat along the axial core mounting hole, the machine body is provided with a stator cooling water jacket between the first bearing seat and the second bearing seat, the spindle cooling structure comprises a first cooling water channel and a second cooling water channel, the first cooling water channel flows through the first bearing seat, the stator cooling water jacket and the second bearing seat, the second cooling water channel flows through the first bearing seat, the stator cooling water jacket and the second bearing seat, and the first cooling water channel and the second cooling water channel are separated.

2. The spindle cooling structure according to claim 1, characterized in that: The first bearing seat is located at the front end of the machine body, and the second bearing seat is located at the rear end of the machine body. The first cooling water channel flows through the first bearing seat, the stator cooling water jacket and the second bearing seat in sequence, and the second cooling water channel flows through the first bearing seat, the stator cooling water jacket and the second bearing seat in sequence.

3. The spindle cooling structure according to claim 2, characterized in that: The first bearing seat is integrally formed at the front end of the machine body, and the outer wall surface of the first bearing seat is provided with a first annular groove and a second annular groove, the first annular groove and the second annular groove are separated from each other, and the outer side of the first bearing seat is provided with a machine body outer sleeve, and the machine body outer sleeve covers the first annular groove and the second annular groove, the first cooling water channel extends along the machine body to the first annular groove, and enters the stator cooling water jacket after circulating along the first annular groove, and the second cooling water channel extends along the machine body to the second annular groove, and enters the stator cooling water jacket after circulating along the second annular groove.

4. The spindle cooling structure according to claim 2, characterized in that: The outer wall surface of the stator cooling water jacket is provided with a first water jacket water channel and a second water jacket water channel, and the first water jacket water channel and the second water jacket water channel are separated from each other. The body is sleeved on the outer wall surface of the stator cooling water jacket and shields the first water jacket water channel and the second water jacket water channel. The first cooling water channel flows through the first bearing seat and then flows into the first water jacket water channel, and the second cooling water channel flows through the first bearing seat and then flows into the second water jacket water channel.

5. The spindle cooling structure according to claim 4, characterized in that: The outer wall surface of the stator cooling water jacket includes a left outer wall surface and a right outer wall surface which are arranged in a mirror image. The first water jacket water channel is arranged in an S shape on the left outer wall surface, and the second water jacket water channel is arranged in an S shape on the right outer wall surface. The first water jacket water channel forms an inlet at one end close to the first bearing seat and an outlet at one end close to the second bearing seat. The second water jacket water channel forms an inlet at one end close to the first bearing seat and an outlet at one end close to the second bearing seat.

6. The spindle cooling structure according to claim 2, characterized in that: A third annular groove and a fourth annular groove are provided on the outer periphery of the second bearing seat, and the third annular groove and the fourth annular groove are separated from each other. The first cooling water channel flows through the stator cooling water jacket and then enters the third annular groove, circulates along the third annular groove and then flows out. The second cooling water channel flows through the stator cooling water jacket and then enters the fourth annular groove, circulates along the fourth annular groove and then flows out.

7. The spindle cooling structure according to claim 6, characterized in that: The first cooling water channel and the second cooling water channel are provided with a water inlet and a water outlet on the second bearing seat.

8. The spindle cooling structure according to claim 6, characterized in that: The second bearing seat is separately arranged from the machine body, and the outer wall surface of the second bearing seat is provided with a third annular groove and a fourth annular groove. The second bearing seat is embedded in the rear end of the machine body, and the machine body shields the third annular groove and the fourth annular groove.

9. A spindle, characterized in that: The invention comprises the spindle cooling structure according to any one of claims 1 to 8.

10. A machine tool, characterized in that: Comprising the main shaft as claimed in claim 9.

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