A cooling water jacket for an electric spindle with a turbulence-inducing structure

Abstract

This invention relates to the field of CNC machine tool electric spindle technology and provides an electric spindle cooling water jacket with a turbulence structure. The cooling water jacket has a spiral flow channel, which consists of continuously alternating inlet and outlet channels. Turbulence structure one and turbulence structure two are respectively arranged within the inlet and outlet channels. Both turbulence structure one and turbulence structure two consist of turbulence columns and turbulence ribs, with the turbulence columns located at the rear center of the two turbulence ribs. This invention improves heat exchange efficiency and avoids increased energy consumption by optimizing the turbulence structure without changing the coolant flow rate and temperature. The design of the spiral flow channel and turbulence structure enhances heat exchange in high-temperature areas, effectively reducing the maximum temperature of the cooling water jacket and the temperature in corresponding areas. Moreover, compared with a double-spiral cooling water jacket, the overall heat exchange performance of this invention is improved. At the same time, the overall structure of the cooling water jacket requires minimal modification, reducing manufacturing costs.

Description

Technical Field

[0001] This invention belongs to the field of CNC machine tool electric spindle technology, and particularly relates to an electric spindle cooling water jacket with a turbulence structure. Background Technology

[0002] In modern manufacturing, machine tools, as core equipment for precision machining, directly impact the quality and market competitiveness of industrial products. Among these, high-speed, high-precision electric spindle units are core functional components of high-end CNC machine tools. Compared to traditional mechanical spindles, electric spindles feature "zero transmission," eliminating intermediate transmission devices and integrating the machine tool spindle with the drive motor, which directly drives the spindle unit. Furthermore, electric spindles offer advantages such as compact structure, light weight, fast dynamic response, and high rotational accuracy. However, during operation, the internal heat source of the electric spindle generates heat, leading to temperature rise and subsequent thermal deformation. This not only reduces machining accuracy but also shortens the spindle's lifespan. Research shows that thermal errors account for 40%-70% of the various errors affecting the machining accuracy of CNC machine tools. Therefore, the thermal performance of the spindle system is crucial for the lifespan and machining accuracy of CNC machine tools, making it essential to improve the cooling effect of the electric spindle cooling unit.

[0003] Currently, electric spindles primarily dissipate heat by injecting low-temperature coolant into the cooling water jacket. The coolant removes the heat generated inside the electric spindle through convection heat transfer. Although the heat transfer efficiency can be altered by adjusting relevant coolant parameters (such as coolant flow rate and temperature) and the cooling water jacket structure (such as cooling water jacket type and structural parameters), the following shortcomings still exist:

[0004] (1) Coolant-related parameters: Most of the heat generated by the heat source inside the electric spindle is transferred to the outside through the convection heat transfer of the coolant. Increasing the coolant flow rate and decreasing the coolant inlet temperature can increase the coolant convection heat transfer coefficient and enhance heat transfer, thereby improving the heat transfer efficiency of the cooling water jacket. However, increasing the coolant flow rate and decreasing the temperature have limited effect on improving the heat transfer efficiency and will lead to an increase in the energy consumption of the cooling unit.

[0005] (2) Cooling water jacket structure: Different cooling water jacket structures have different cooling effects, and adjusting the size parameters and cross-sectional shape of the flow channel also has different effects on the cooling effect. However, when adjusting the above factors, there is often a lack of specific consideration for cooling high-temperature areas. In addition, some improvement schemes require significant modifications to the cooling water jacket structure, which will increase the manufacturing cost of the cooling water jacket.

[0006] To address the above problems, this invention proposes an electric spindle cooling water jacket with a turbulence-inducing structure. Summary of the Invention

[0007] The purpose of this invention is to provide an electric spindle cooling water jacket with a turbulence structure, which aims to solve the problems mentioned in the background art.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A cooling water jacket for an electric spindle with a turbulence structure is provided. The cooling water jacket is fixed on the electric spindle, and the outer shell of the electric spindle is tightly fitted with the cooling water jacket. The cooling water jacket has an inlet and an outlet, and a spiral flow channel is provided on the cooling water jacket. The spiral flow channel is composed of continuously alternating inlet and outlet flow channels. A turbulence structure one and a turbulence structure two are respectively provided in the inlet and outlet flow channels. Both the turbulence structure one and the turbulence structure two are composed of turbulence columns and turbulence ribs. The turbulence columns are located in the middle of the rear of the two turbulence ribs.

[0010] In the first turbulence structure, the turbulence column is the inlet channel turbulence column, and the two turbulence ribs on both sides are the inlet channel turbulence rib one and the inlet channel turbulence rib two. The included angle formed between the inlet channel turbulence column and the two inlet channel turbulence ribs on both sides is directly opposite to the coolant flow direction.

[0011] In the second turbulence structure, the turbulence column is the outlet flow channel turbulence column, and the two turbulence ribs on both sides are outlet flow channel turbulence rib one and outlet flow channel turbulence rib two. The included angle formed between the outlet flow channel turbulence column and the two outlet flow channel turbulence ribs on both sides is directly opposite to the coolant flow direction.

[0012] Furthermore, the structure of the turbulence column is a column with a straight-sided ellipse as its cross-section.

[0013] Furthermore, the angle φ of the turbulence column is 10°.

[0014] Furthermore, the type of the turbulence rib is a discontinuous oblique rib.

[0015] Furthermore, the width b of the spoiler rib is 2mm.

[0016] Furthermore, the upper width w1 between the two sides of the spoiler ribs is 8mm, and the lower width w2 between the two sides of the spoiler ribs is 10mm.

[0017] Furthermore, the turbulence columns and turbulence ribs are evenly distributed in the inlet and outlet channels.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention improves heat exchange efficiency and avoids increased energy consumption by optimizing the turbulence structure without changing the coolant flow rate and temperature. Specifically, through the ingenious design of the spiral flow channel and turbulence structure, this invention provides enhanced heat exchange in high-temperature areas, effectively reducing not only the maximum temperature of the cooling water jacket and the temperature in the corresponding areas, but also improving the overall heat exchange performance compared to a double-spiral cooling water jacket. Furthermore, this invention requires minimal modification to the overall structure of the cooling water jacket, reducing manufacturing costs. This invention is of great significance for improving the performance and service life of electric spindles, and has practical application value, particularly in high-end CNC machine tools such as tilting milling heads. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural diagram of a separate cooling water jacket flow channel.

[0021] Figure 2 This is a three-dimensional structural diagram of the turbulence-causing channel.

[0022] Figure 3 This is a dimensional diagram of the turbulence structure.

[0023] Figure 4 The results are based on the sensitivity analysis of the size of the turbulent structure.

[0024] Figure 5 This is the result of improvements to the dimensions of the turbulence-causing structure.

[0025] Figure 6 This refers to the flow state of the coolant within the vertical plane of the flow channel.

[0026] Figure 7 This refers to the flow state of the coolant within the horizontal plane of the flow channel.

[0027] Figure 8 This refers to the flow state of the coolant within the cross-section of the flow channel.

[0028] Figure 9 This is a cloud map showing the heat transfer coefficient distribution within the flow channel.

[0029] Figure 10 This is a schematic diagram of the three-dimensional structure of the cooling water jacket.

[0030] Figure 11 This is the front view of the cooling water jacket.

[0031] Figure 12 This is a three-dimensional structural diagram of an electric spindle.

[0032] Figure 13 A three-dimensional structural diagram of the electric spindle after removing the outer casing and installing the cooling water jacket.

[0033] In the diagram: 1. Cooling water jacket flow channel; 2. Turbulence structure flow channel; 3. Cooling water jacket; 4. Inlet flow channel turbulence column; 5. Inlet flow channel turbulence rib one; 6. Inlet flow channel turbulence rib two; 7. Outlet flow channel turbulence column; 8. Outlet flow channel turbulence rib one; 9. Outlet flow channel turbulence rib two; 10. Inlet; 11. Outlet; 12. Electric spindle; 13. Housing. Detailed Implementation

[0034] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0035] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0036] This invention provides a cooling water jacket for an electric spindle with a turbulence structure. To improve the heat exchange efficiency of the cooling water jacket 3 in high-temperature regions and to address the thermal characteristics of the electric spindle 12 at low cost, a separate cooling water jacket flow channel 1 is used as the design object. Figure 1 ), and a turbulence-inducing structure is arranged in the flow channel, namely the turbulence-inducing structure flow channel 2 ( Figure 2 The turbulence structure in flow channel 2 includes turbulence ribs and turbulence pillars. The turbulence ribs are discontinuous oblique ribs, with their orientation opposite to the coolant flow direction. The turbulence pillars are cylinders with a straight-sided ellipse cross-section, located at the rear center of the two turbulence ribs. The turbulence ribs and pillars are evenly distributed within the flow channel. The dimensional diagram of the turbulence structure is shown below. Figure 3 As shown, the dimensions include the width b of the turbulence rib, the upper width w1 of the turbulence rib, the lower width w2 of the turbulence rib, and the angle φ of the turbulence column. A sensitivity analysis of the dimensions of the turbulence structure is performed, and the sensitivity of each dimension to the flow channel pressure drop, temperature, and fluid Nusselt number is shown below. Figure 4 As shown, it can be seen that, except for the width b of the turbulence rib, the other dimensions have a significant impact on various parameters of the flow channel. When the width w1 of the upper turbulence rib and the width w2 of the lower turbulence rib increase, the flow channel pressure drop and the fluid Nusselt number decrease, while the flow channel temperature increases; when the angle φ of the turbulence column increases, the flow channel pressure drop and the fluid Nusselt number increase, while the flow channel temperature decreases. Based on the above analysis results, the dimensions of the turbulence structure are improved, and the improvement results are as follows. Figure 5 As shown, the width b of the spoiler rib is 2mm, the upper width w1 between the two spoiler ribs is 8mm, the lower width w2 between the two spoiler ribs is 10mm, and the angle φ of the spoiler column is 10°.

[0037] Figure 6The flow pattern of coolant within the vertical plane of the flow channel is shown. Under the influence of the turbulence column, the coolant above the turbulence column has a relatively high flow velocity. When the coolant on both sides of the turbulence column flows behind the turbulence column, it will flow towards the middle vertical plane and impact when they meet, thus generating two opposing flows within the vertical plane. The downward-flowing fluid further forms a more obvious vortex within the vertical plane when it reaches the bottom of the flow channel.

[0038] Figure 7 The flow pattern of coolant in the horizontal plane of the flow channel is shown. Under the influence of the turbulence ribs, the coolant velocity in the middle region of the flow channel is relatively high, and a more obvious vortex is formed behind the turbulence ribs. Under the influence of the turbulence columns, the coolant velocity on both sides of the turbulence columns is relatively high, and due to the influence of the vortex in the vertical plane and the fluid on both sides of the turbulence columns in the horizontal plane, two vortices with opposite rotation directions are formed in the horizontal plane behind the turbulence columns.

[0039] Figure 8 The flow state of coolant within the cross-section of the flow channel is shown. Under the influence of vortices on both sides of the flow channel, the flow velocity on both sides of the cross-section is low, while the flow velocity of coolant in the middle area is high. Furthermore, the coolant at the bottom of the middle area is affected by the vortex behind the turbulence column, which also generates vortices with opposite rotation directions within the cross-section. The vortex area roughly presents a triangular region.

[0040] Figure 9 The diagram shows the heat transfer coefficient distribution within the flow channel. In the central region, the coolant velocity is higher due to the influence of the turbulence structure. Furthermore, the boundary layer disruption and enhanced fluid mixing caused by fluid disturbance improve the channel's heat transfer capacity, resulting in a higher heat transfer coefficient in the central section. The heat transfer coefficient is highest at the contact point between the turbulence column and the bottom surface of the channel. Behind the turbulence ribs, the flow velocity is lower due to vortex influence, leading to a lower heat transfer coefficient compared to other regions. However, overall, the channel's heat transfer capacity is still improved.

[0041] like Figures 10-13 As shown, in a preferred embodiment of the present invention, the cooling water jacket 3 is fixed on the electric spindle 12, and the outer shell 13 of the electric spindle 12 is tightly fitted together with the cooling water jacket 3. The cooling water jacket 3 has an inlet 10 and an outlet 11, and a spiral flow channel is formed on the cooling water jacket 3; the spiral flow channel is composed of continuously alternating inlet and outlet flow channels, and a first turbulence structure and a second turbulence structure are respectively provided in the inlet and outlet flow channels. These turbulence structures are all composed of turbulence columns and turbulence ribs, and the included angles formed are all facing the direction of coolant flow.

[0042] Specifically, the inlet channel is provided with a first turbulence structure consisting of an inlet channel turbulence column 4, an inlet channel turbulence rib 1 5, and an inlet channel turbulence rib 2 6. The included angle formed between the inlet channel turbulence column 4 and the two sides of the inlet channel turbulence rib 1 5 and the two sides of the inlet channel turbulence rib 2 6 is directly opposite to the direction of coolant flow. The outlet channel is provided with a second turbulence structure consisting of an outlet channel turbulence column 7, an outlet channel turbulence rib 1 8, and an outlet channel turbulence rib 2 9. The included angle formed between the outlet channel turbulence column 7 and the two sides of the outlet channel turbulence rib 1 8 and the two sides of the outlet channel turbulence rib 2 9 is directly opposite to the direction of coolant flow.

[0043] In this embodiment of the invention, the working principle is as follows: the coolant flows into the cooling water jacket 3 through the inlet 10, and after being disturbed by the spiral flow channel and the turbulence structure, it flows out through the outlet 11. This flow path ensures that the coolant can fully contact the inner wall of the cooling water jacket 3 and carry away the heat generated inside the electric spindle 12.

[0044] The arrangement of the turbulence structure not only increases the heat exchange area of ​​the cooling water jacket 3 and enhances the heat exchange efficiency, but also strengthens the mixing of the coolant and the disruption of the coolant boundary layer by disturbing the flow state of the coolant, thereby further enhancing the convective heat transfer in the corresponding area.

[0045] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A cooling water jacket for an electric spindle with a turbulence-inducing structure, wherein the cooling water jacket is fixed to the electric spindle, the outer shell of the electric spindle is tightly fitted with the cooling water jacket, and the cooling water jacket has an inlet and an outlet, characterized in that, The cooling water jacket is provided with a spiral flow channel, which is composed of a continuously alternating inlet flow channel and an outlet flow channel. A turbulence structure one and a turbulence structure two are respectively provided in the inlet flow channel and the outlet flow channel. Both the turbulence structure one and the turbulence structure two are composed of turbulence columns and turbulence ribs. The turbulence columns are located in the middle of the rear of the two turbulence ribs. In the first turbulence structure, the turbulence column is the inlet channel turbulence column, and the two turbulence ribs on both sides are the inlet channel turbulence rib one and the inlet channel turbulence rib two. The included angle formed between the inlet channel turbulence column and the two inlet channel turbulence ribs on both sides is directly opposite to the coolant flow direction. In the second turbulence structure, the turbulence column is the outlet flow channel turbulence column, and the two turbulence ribs on both sides are outlet flow channel turbulence rib one and outlet flow channel turbulence rib two. The included angle formed between the outlet flow channel turbulence column and the two outlet flow channel turbulence ribs on both sides is directly opposite to the coolant flow direction.

2. The electric spindle cooling water jacket with a turbulence-inducing structure according to claim 1, characterized in that, The structure of the turbulence column is a column with a straight-sided ellipse as its cross-section.

3. The electric spindle cooling water jacket with a turbulence-inducing structure according to claim 1, characterized in that, The angle φ of the turbulence column is 10°.

4. The electric spindle cooling water jacket with a turbulence-inducing structure according to claim 1, characterized in that, The type of the turbulence rib is the intermittent oblique rib.

5. The electric spindle cooling water jacket with a turbulence-inducing structure according to claim 1, characterized in that, The width b of the spoiler rib is 2mm.

6. The electric spindle cooling water jacket with a turbulence-inducing structure according to claim 1, characterized in that, The upper width w1 between the two sides of the spoiler ribs is 8mm, and the lower width w2 between the two sides of the spoiler ribs is 10mm.

7. The electric spindle cooling water jacket with a turbulence-inducing structure according to claim 1, characterized in that, The turbulence-disrupting columns and ribs are evenly distributed in the inlet and outlet channels.

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