CN201236887Y - Ring groove cooling water lubricated dynamic-static high-speed bearing - Google Patents

Abstract

The utility model relates to a hybrid high-speed bearing with lubrication of cooling water in a ring groove. The hybrid high-speed bearing comprises a bearing body and a plurality of groups of oil cavities including deep cavities and shallow cavities and formed in the middle of the inner wall of the bearing body, oil inlet holes are formed on the deep cavities, circumferential oil sealing surfaces are arranged between adjacent oil cavities for separation, the oil cavities and the edge of the bearing body form axial oil sealing surfaces, ring grooves are symmetrically formed on the axial oil sealing surfaces on two sides of the oil cavities, and cooling holes penetrating the wall surface of the bearing body are formed on the ring grooves. ring grooves are formed on the axial oil sealing surfaces with the maximum heating value and the cooling holes are formed to be accessed with lubricating medium, so that the heat medium is mixed with normal temperature medium and the pressure gradient of the area is reduced, so as to achieve the purpose of reducing the temperature rise on the premise of reducing the influence on the rigidity to the minimum.

Description

Ring groove cooling water lubricated dynamic and static pressure high-speed bearings

technical field

The utility model relates to a high-speed precision machine tool bearing, in particular to a ring groove cooling water lubricated dynamic and static pressure high-speed bearing.

Background technique

With the increasingly urgent demand for high-speed and high-precision machining, people have proposed the use of low-viscosity medium lubricated dynamic and static pressure bearing technology, using the physical characteristics of low viscosity and large specific heat of water and the dynamic pressure effect of the bearing at high speed to make the bearing work. The temperature rise is very low, and it can provide sufficient rigidity and bearing capacity. The support technology of water-lubricated dynamic and static pressure sliding bearings for high-speed precision machine tool spindles mainly includes deep cavity bearings and stepped cavity bearings.

Deep cavity bearings use a cavity similar to hydrostatic bearings, use the enhanced dynamic pressure effect at high speeds to compensate for the reduction in stiffness caused by the use of low-viscosity media, and use the large specific heat and large flow rate of water to control temperature rise. The stiffness of this type of bearing is about 1×10 ⁸ N/m to 5×10 ⁸ N/m, and the temperature when d _m N (the product of bearing diameter and speed, used to measure the mechanical index of the bearing) is below 1×10 ⁶ The temperature rise can still meet the requirements, but due to the influence of turbulent internal friction, it is difficult to control the temperature rise when d _m ·N is large. This type of bearing is mainly used in medium and high speed grinding machines (Zhang Guoyuan, Yuan Xiaoyang. A theoretical study on the three-dimensional pressure and temperature field distribution of water-lubricated dynamic and static pressure bearings [J] Lubrication and Sealing, Issue 8, August 2006 (Total Issue 180)).

The stepped cavity bearing can greatly enhance the dynamic pressure effect by using the stepped cavity, so that the bearing has high rigidity and is suitable for high-speed cutting machine tools (Zhang Yabin. Design research on water-lubricated dynamic and static pressure bearings for high-speed machine tools [D]. Xi'an Jiaotong University Master's Degree Thesis 2008 ), is a technology with great potential, but when d _m · N exceeds 1×10 ⁶ , the temperature rise will greatly affect its accuracy (Guo Ce, Sun Qinghong. Analysis of thermal characteristics and thermal characteristics of high-speed and high-precision CNC lathe spindle system Deformation calculation [J]. Journal of Southeast University, March 2005, Vol. 35, No. 2 (Natural Science Edition)), there is no domestic application of bearings with a d _m ·N value higher than 5×10 ⁵ (Guo Hongsheng, Jiao Rang, Zhang Jie, Niu Ben. Application Research of Water Lubricated High Speed Dynamic and Static Sliding Bearings in Machining [J] Manufacturing Technology and Machine Tools, Issue 9, 2007).

When the _water -lubricated dynamic and static pressure sliding bearings currently used exceed 1× ¹⁰⁶ , there is a great contradiction between high stiffness and low temperature rise. On the one hand, it is desirable to maximize the stiffness to achieve high stability and large cutting Power, on the other hand, must prevent thermal deformation caused by temperature rise from reducing accuracy.

The design goals of high-speed dynamic and static pressure bearings are mainly high stiffness and low temperature rise. When the bearing is running, the relative speed between the journal and the bearing bush is extremely high, which can generate a strong velocity flow, and its dynamic pressure effect is very significant. The appropriate bearing structure can achieve high rigidity. However, as the speed increases, the medium inside Friction will also be greatly enhanced. Internal friction is the main source of heat generated by liquid bearings. The high-speed flow of fluid under small gaps is the main cause of internal friction.

The oil chamber of dynamic and static pressure bearings is generally located in the middle of the bearing bush, and the oil inlet hole is arranged in the oil chamber. When the medium enters the shallow cavity, the flow velocity decreases and the pressure increases. The deep cavity in the stepped cavity enables the medium to fill the oil cavity, and the shallow cavity allows the medium to gradually decelerate and increase the pressure, while reducing the turbulent effect of the medium. The heat of the bearing is mainly generated on the oil sealing surface. This is because the flow gap on the oil sealing surface is small, and the medium is subjected to strong shear force, and the internal friction heat is serious. Since the temperature rise is mainly concentrated on the axial oil sealing surface, this is because the flow rate of the medium on the axial oil sealing surface is extremely high, and the gap is small, and the internal friction generates a lot of heat. In fact, each part of the bearing bush has different effects on the dynamic and static characteristics of the bearing. The circumferential oil sealing surface and shallow cavity constitute the main conditions for the formation of the dynamic pressure effect, while the axial oil sealing surface prevents the medium from flowing out from both sides of the bearing, which has a great impact on the dynamic and static characteristics. Features are less affected.

Contents of the invention

The purpose of the utility model is to provide a ring groove cooling water lubricated dynamic and static pressure high-speed bearing which not only satisfies the high rigidity of the bearing, but also can control the temperature rise within the acceptable range of precision machining.

In order to achieve the above purpose, the technical solution adopted by the utility model is: including the bearing body and several groups of oil chambers composed of deep cavities and shallow cavities set in the middle of the inner wall of the bearing body, and oil inlet holes are opened on the deep cavities, adjacent to each other. The oil chambers are separated by a circumferential oil sealing surface, and the edge of the oil chamber and the bearing body forms an axial oil sealing surface, and ring grooves are symmetrically opened on the axial oil sealing surfaces on both sides of the oil chamber, and there are ring grooves in the ring grooves. There are cooling holes through the wall of the bearing body.

Because the utility model opens a ring groove on the axial oil sealing surface with the largest heat generation and opens a cooling hole to pass through the lubricating medium, so that the heat medium is mixed with the normal temperature medium, and the pressure gradient here is reduced, so as to achieve as small a temperature as possible. The purpose of lowering the temperature rise is the premise of effectively affecting the stiffness. The function of the ring groove: 1. Accelerate the flow of the medium on the axial oil sealing surface, enhance the velocity flow component, and cause heat transfer due to internal friction; 2. Increase the cross-sectional area of the axial oil sealing surface and increase the flow rate of the oil sealing surface. Reduce temperature rise. The function of the cooling hole: 1. To pass through the medium with a certain pressure to carry out forced heat exchange, so that the heat medium heated up by internal friction is mixed with the normal temperature medium to achieve the effect of reducing the surface temperature of the bearing bush; 2. To compensate for the rigidity caused by the ring groove Decrease, improve the static and dynamic characteristics of the bearing.

Description of drawings

Fig. 1 is the overall structural representation of the utility model;

Fig. 2 is a side view of the utility model;

Fig. 3 is an example of performance comparison between the utility model and the prior art (d _m ·N=1.75×10 ⁶ , oil inlet temperature 30°C).

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Referring to Figures 1 and 2, the utility model includes a bearing body 9 and several groups of oil chambers consisting of deep chambers 4 and shallow chambers 5 set in the middle of the inner wall of the bearing body 9, and an oil inlet hole 1 is opened on the deep chamber 4, correspondingly There is a circumferential oil sealing surface 2 between the adjacent oil chambers, the oil chamber and the edge of the bearing body 9 form an axial oil sealing surface 3, and ring grooves 7 are symmetrically opened on the axial oil sealing surfaces 3 on both sides of the oil chamber , and a cooling hole 8 penetrating through the wall of the bearing body 9 is opened in the ring groove 7 .

The high-pressure lubricating medium enters the deep cavity 4 through the oil inlet hole 1, and is driven by the high-speed rotating journal 6 to flow in the oil cavity at high speed. When the medium enters the shallow cavity 5, the flow rate decreases and the pressure increases. The deep cavity 4 in the stepped cavity enables the medium to fill the oil cavity, and the shallow cavity 5 enables the medium to gradually decelerate and increase the pressure, while reducing the turbulence effect of the medium. The heat of the bearing is mainly generated on the oil sealing surfaces 2 and 3. This is because the flow gap on the oil sealing surfaces is small, and the medium is subjected to strong shear force, and the internal friction heat is serious. Since the temperature rise is mainly concentrated on the axial oil sealing surface 3, this is because the flow rate of the medium on the axial oil sealing surface is extremely high, and the gap is small, and the internal friction generates a lot of heat. In fact, each part of the bearing bush has different effects on the static and dynamic characteristics of the bearing. The circumferential oil sealing surface 2 and the shallow cavity 5 constitute the main conditions for the formation of the dynamic pressure effect, while the axial oil sealing surface 3 prevents the medium from flowing out from both sides of the bearing. , has little effect on the dynamic and static characteristics. Therefore, the utility model opens a ring groove 7 on the axial oil sealing surface 3 with the largest calorific value, thereby increasing the flow cross-sectional area, increasing the flow rate, reducing the temperature rise, and reducing the temperature rise of the entire bearing, and in the ring groove 7 A cooling hole 8 is opened on the top, through which the lubricating medium is introduced, the heat medium is mixed with the normal temperature medium, and the pressure gradient here is reduced, so as to achieve the purpose of reducing the temperature rise on the premise of affecting the stiffness as little as possible.

The advantages of the utility model in stiffness and temperature rise can be illustrated by calculating the flow rate, bearing capacity, equivalent stiffness, and average temperature rise of the structure of the utility model with other structures of the same size, as shown in Figure 3: the utility model in terms of temperature rise It has great advantages, the temperature rise is only about 10% of the prior art, and the stiffness reaches more than 1.2×10 ⁹ N/m. When d _m ·N is larger, the advantage of the utility model in terms of temperature rise will be more obvious, and the rigidity will be further improved. After optimized design, the equivalent stiffness of the utility model can reach more than 1.2×10 ⁹ N/m, the average temperature rise is within 2°C, and the flow rate is within 20L/min.

Claims (1)

1. The ring groove cooling water lubricates the dynamic and static pressure high-speed bearings, including the bearing body (9) and several groups of oil chambers consisting of deep chambers (4) and shallow chambers (5) set in the middle of the inner wall of the bearing body (9). The cavity (4) is provided with an oil inlet hole (1), and the adjacent oil cavity is separated by a circumferential oil sealing surface (2), and the edge of the oil cavity and the bearing body (9) forms an axial oil sealing surface ( 3), characterized in that ring grooves (7) are formed symmetrically on the axial oil sealing surfaces (3) on both sides of the oil chamber, and in the ring grooves (7) there are grooves penetrating through the wall surface of the bearing body (9). cooling holes (8).

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