KR101017842B1 - Chiller of ball screw assembly - Google Patents

Abstract

The present invention relates to a cooling device for a ball screw assembly, comprising: a heat absorbing portion inserted between an outer diameter portion and an inner diameter portion of the ball nut to absorb heat; A heat pipe extending from the heat absorbing part and configured to be exposed to the outside; And a heat dissipation member extending with the condenser of the heat pipe and dissipating heat transferred from the evaporator.

Providing the invention as described above, the device configuration is much easier and the production cost is lower than the device by the conventional cooling flow circulation, it is possible to increase the high efficiency and durability. In addition, there is an advantage that it is possible to prevent the degradation of the performance due to the oxidation and bearing penetration of the machine tool by the cooling flow is not used.

Heat Pipes, Ball Screws, Ball Nuts, Machine Tools

Description

Cooling system of ball screw assembly

The present invention relates to a ball screw assembly used for converting a rotational motion into a linear motion, and more particularly, to a cooling device of a ball screw assembly to improve productivity and quality with high cooling efficiency and durability.

In general, the ball screw assembly (ball screw assembly) is a device that converts the rotational clouds into linear motion. In particular, ball screw assemblies used in machine tools or multi-task machines that require high speed accuracy require a cooling device to remove kinetic frictional heat generated during high speed driving.

Therefore, the ball screw cooling device increases the processing degree by minimizing the heat displacement of the ball screw, and also improves the life of the ball screw.

Conventionally, Japanese Patent Laid-Open No. 2000-230617, Japanese Patent Laid-Open No. 2001-295909, Japanese Patent Laid-Open No. 2002-310258, Japanese Patent Laid-Open No. 2002-372119, and Japanese Patent Laid-Open No. 2003-172427 are disclosed as prior arts related to ball screw cooling devices.

Japanese Patent Laid-Open No. 2000-230617 implements cooling of a ball nut and lubrication of a ball receiving part by flowing air / oil mist into a screw ball via an air supply path formed in the ball nut.

Japanese Patent Laid-Open No. 2001-295909 firstly supplies coolant through a cooling medium conduit installed inside the ball screw shaft to discharge it in a U-shape, and secondly, coolant is supplied through a spiral cooling medium flow path into the ball nut and then discharged in the reverse direction. In this way, the temperature detector is configured so as not to exceed the critical temperature of the grease.

Japanese Patent Laid-Open No. 2002-310258 communicates a cooling fluid circulation groove formed in a ball nut with a slot of both covers to circulate and discharge the cooling fluid in a zigzag to achieve cooling.

Japanese Patent Laid-Open No. 2002-372119 forms a plurality of cooling holes in the circumferential axial direction of the ball nut, and realizes cooling by ventilation made up of the cooling holes when the ball nut is moved in the ball screw shaft.

Japanese Patent Laid-Open No. 2003-172427 fills a cavity formed in a circular shape inside a ball nut with a coolant having excellent heat transfer ability.

That is, a general conventional ball screw cooling apparatus attaches a rotating union 10 in the form of a through flow to the end of the ball screw, as shown in FIG. The refrigerant is introduced into 12) and the refrigerant is recovered through the hole 12a on the side of the ball screw on the opposite side.

At this time, the ROTATING SEAL 14 is used to prevent leakage of the refrigerant. In this structure, initial refrigerant leakage occurs depending on the quality of the rotating seal. In addition, even if there is no initial refrigerant leakage, wear of the rotating chamber 14 is generated due to continuous rotational friction during operation of the sub-motor (M), which causes the amount of refrigerant leakage to increase over time. As a result, the replenishment period of the refrigerant becomes shorter and shorter.

In addition, in such a structure, if a problem occurs in the cooling mechanism of the ball screw, in order to correct it, the motor bracket must be completely disassembled, the relevant parts must be corrected, the parts related to the overall ball screw assembly must be readjusted, and then assembled.

As such, it is difficult to manufacture because the cooling flow path must be formed directly on the inner body of the ball screw and the ball nut. In addition, when the cooling flow path is applied as a split structure, not only the structural change of the ball nut has to be applied, but also the number of assembly parts is increased, resulting in poor quality and productivity.

In addition, since most of the cooling flow paths are used, a sealing device is required to prevent leakage of the cooling fluid. Such cooling fluid is leaked even when the sealing device is slightly worn, so that the sealing device must maintain an improved sealing function. There is difficulty. In addition, there is a problem that the leakage of the cooling oil due to the cooling flow path is not only a problem, but also the complexity of the additional device for the circulation of the cooling oil and the cooling efficiency is low.

The problem of the present invention for solving the above problems can be configured a simple and highly efficient cooling device without the configuration of a conventional complex cooling device, there is no use of the cooling oil, the oxidation of the equipment and cooling oil due to the cooling oil leakage The purpose is to prevent the durability and productivity of the equipment by bearing penetration.

In addition, to increase the degree of freedom of configuration to increase the cooling efficiency in various ways, to lower the production cost and to increase the convenience of repair and repair work.

The first feature of the present invention for solving the above problems is a ball screw assembly for converting the rotational power of the ball screw shaft into the translational power of the ball nut, inserted between the outer diameter and the inner diameter of the ball nut to heat A heat absorbing portion for absorbing; A heat pipe extending from the heat absorbing part and configured to be exposed to the outside; And a heat dissipation member extending with the condenser of the heat pipe and dissipating heat transferred from the evaporator.

Here, the absorbent portion is preferably an absorbent plate having a cylindrical structure inserted into the outer diameter portion and the inner diameter portion of the ball nut, and the heat pipe is preferably a plurality of heat pipes extending to the absorbent portion.

In addition, the heat dissipation unit is preferably composed of a heat dissipation fin and a heat dissipation fin or a heat dissipation blade extending in a direction perpendicular to the heat dissipation plate, the heat dissipation plate is preferably attached to the side of the workbench located on the upper surface of the ball nut, the heat The refrigerant inserted into the pipe preferably has a boiling point of 10 ° C to 60 ° C.

In addition, the second aspect of the present invention is a ball screw assembly for converting the rotational power of the ball screw shaft into the translational power of the ball nut, the heat absorbing portion inserted between the outer diameter portion and the inner diameter portion of the ball nut to absorb heat ; A heat pipe extending from the heat absorbing part and configured to be exposed to the outside; A heat dissipation member extending to the condensation portion of the heat pipe; And a fan spaced apart from the heat radiating member at a predetermined distance and facing the heat radiating member to dissipate heat generated from the heat radiating member to the outside.

Preferably, the absorbent portion may be an absorbent plate having a cylindrical structure inserted into the outer diameter portion and the inner diameter portion of the ball nut, and the heat pipe may be a plurality of heat pipes extending to the absorbent portion.

In addition, the heat dissipation unit is preferably composed of a heat dissipation plate and a heat dissipation fin or a heat dissipation blade extending in a direction perpendicular to the heat dissipation plate, the heat dissipation plate is preferably attached to the side of the workbench located on the upper surface of the ball nut, the heat The refrigerant inserted into the pipe preferably has a boiling point of 10 ° C to 60 ° C.

By providing such an invention, it is possible to construct a simple and highly efficient cooling device without the configuration of a conventional complicated cooling device, and there is no use of the cooling oil flow, so that the oxidation of equipment and the penetration of the bearing connection of the cooling oil due to leakage of the cooling oil are prevented. The high efficiency of the cooling device can be configured by preventing the durability and productivity decrease of the equipment.

In addition, it is possible to increase the degree of freedom of configuration to increase the cooling efficiency in various ways, to lower the production cost and to increase the convenience of repair and repair work.

First embodiment

2 and 3 are side and front views illustrating the configuration of the cooling device of the ball screw assembly according to the present invention.

As shown in FIG. 2, the assembly of the ball screw includes a ball screw 100, a ball nut 200, a work table, a guide rail 400, a guide 415, and a work table 500. The cooling device of the (100) assembly is composed of a heat absorbing part 310, a heat pipe, and a heat dissipation member 350 inserted into the ball nut 200. In other words, the cooling of the ball nut 200 using a heat pipe using heat exchange generated in a phase shift cycle of the refrigerant, rather than a cooling method using cooling oil, is adopted.

Referring to FIG. 2, in the structure conveying apparatus of a machine tool such as a machining center, a ball screw is rotated by driving of a motor, and a spiral groove is formed in the outer diameter of the ball screw 100, and a corresponding groove nut is formed. 200 and the ball is connected to the translational movement of the ball nut 200 by the rotation of the ball screw (100).

Since the ball screw 100 and the ball nut are driven by the transmission method, a considerable frictional heat is generated at the contact portion, and this frictional heat causes thermal displacement of the ball screw 100 to the ball nut 200. do. This thermal displacement eventually leads to problems with the durability of the feeder and the productivity of the entire machining center.

Therefore, in the present invention, the cooling device is designed to prevent the thermal deformation of the ball screw 100 and the ball nut 200 to compensate for the problems of the conventional cooling method through the circulation of the cooling oil and to increase the cooling efficiency and productivity. The method was conceived.

That is, as shown in Figure 3, in the present invention, the heat absorbing portion 310 is embedded between the outer diameter portion and the inner diameter portion of the ball nut 200 and the ball screw 100 through the heat pipe 300 connected to the absorbing portion It adopts cooling method by transferring heat generated at the time of operation to outside effectively.

Here, the heat absorbing part is made of a material having high thermal conductivity and is inserted into the inner diameter portion and the outer diameter portion of the ball nut 200, and preferably has a cylindrical structure along the shape of the ball nut 200. In order to increase the heat absorption rate, not only the material having high thermal conductivity but also the contact area for generating heat is preferably increased. Therefore, since the structure of the ball nut 200 is cylindrical, the absorption part also has a cylindrical structure. This is because the contact area can be increased to increase the water absorption. In addition to the shape in which the plurality of heat pipes 300 are extended to one absorbing plate, a structure in which the absorbing portion of each heat pipe 300 is inserted and embedded between the outer diameter portion and the inner diameter portion of the ball nut 200 is also possible. to be.

4 is a diagram illustrating a simplified configuration diagram of the heat pipe 300 applied in the present invention. A heat pipe is also called a heat pipe. It was manufactured by General Motors of the United States in 1942 for heat dissipation of spacecraft. It is a vacuum pipe inside, filled with volatile liquid inside of many small holes. When heat is applied at one end of the pipe, the liquid evaporates and moves to the other end with thermal energy. It dissipates at the other end of the pipe and passes through it to return to its original position.

Copper, stainless steel, ceramics, tungsten, and the like are used as the material of the main body, and porous fibers and the like are used for the inner wall. Methanol, acetone, water, mercury, etc. are used as an internal volatile substance. Referring to FIG. 3 in more detail, the heat pipe is a vacuum pipe, and is composed of an evaporator, a heat insulating part, and a condensation part.

A structure having a wick structure is located on the inner wall of the heat pipe, and the refrigerant is partially filled therein. Through this structure, the refrigerant is heated in the evaporator to evaporate inside the heat pipe, and the evaporated gas moves to a condensation unit having a low pressure due to a high pressure.

The condensation part is a portion cooled by rain in the evaporation part, and the refrigerant gas condenses again to liquefy. The refrigerant reduced to liquid is moved to the evaporator by capillary action along the wick structure on the inner wall of the heat pipe. Through such phase change cycle of the refrigerant, the refrigerant vaporizes the heat to be vaporized from the condenser to the outside to cool the cooled object.

On the other hand, the heat dissipation member 350 is preferably composed of a heat dissipation plate 355 and the heat dissipation fin 357. 2 and 3, the heat dissipation member 350 is installed on the side of the working table 500 to expose the outside air, it is preferable to be configured to induce cooling and heat emission more efficiently. The heat dissipation plate 355 exposed to the outside air is wide and the heat dissipation fin 357 has a cross-sectional area of high heat dissipation efficiency, thereby improving the performance of the entire heat pipe. Therefore, the heat sink 355 is determined according to the configuration efficiency and system stability of the entire cooling system, and the heat sink fin 357 or the heat sink can be selected in shape, size and number to allow contact with the outside air in a large area. Of course.

The cooling efficiency may depend on the performance of the heat pipe itself, but may also be improved by the number of heat pipes connected to the heat absorbing part 310 embedded between the outer diameter and the inner diameter of the ball nut 200. Therefore, by mounting a plurality of heat pipes in consideration of the design process, it is of course possible to increase the cooling efficiency.

Second embodiment

FIG. 5 illustrates a plan view of a chiller structure of a ball screw 100 assembly as a second embodiment according to the present invention. As shown in FIG. 4, the assembly of the ball screw 100 is a configuration including a ball screw 100, a ball nut 200, a workbench, a guide rail, and a guide, and a cooling device of such a ball screw 100 assembly. Is inserted between the inner and outer diameter portion of the ball nut 200 is embedded heat absorbing portion 310, extending with the absorbing portion to transfer the heat generated from the ball nut 200 and the ball screw 100 to the outside A heat pipe 300, the heat pipe 300 is connected to the heat pipe 300, and a heat dissipation member 350 and includes a fan to facilitate the more efficient discharge of heat generated from the heat radiation member 350 It is made up.

Herein, the heat absorbing part 310 is installed by being inserted into the inner and outer diameter parts of the ball nut 200 using a material having high thermal conductivity, and preferably has a cylindrical structure along the shape of the ball nut 200. Do. In order to increase the heat absorption rate, not only the material having high thermal conductivity but also the contact area for generating heat is preferably increased. Therefore, since the structure of the ball nut 200 is cylindrical, the absorption part also has a cylindrical structure. This is because the contact area can be increased to increase the water absorption. In addition to the shape in which the plurality of heat pipes 300 are extended to one absorbing plate, a structure in which the absorbing portion of each heat pipe 300 is inserted and embedded between the outer diameter portion and the inner diameter portion of the ball nut 200 is also possible. to be.

The heat dissipation member 350 is mounted at the end of the heat pipe 300, and when the refrigerant inside the heat pipe vaporizes and moves to the condenser, the refrigerant is liquefied because it is exposed to the outside and is relatively cooler than the evaporator. The liquid liquefied refrigerant is moved back to the evaporator to form a phase change cycle semi-permanently, thereby releasing heat generated from the ball screw 100 and the ball nut 200 to the outside and cooling it.

The heat dissipation member 350 is preferably composed of a heat dissipation plate 355 and a heat dissipation fin 357. The heat dissipation plate 355 exposed to the outside air is wide and the heat dissipation fin 357 has a cross-sectional area of high heat dissipation efficiency, thereby improving the performance of the entire heat pipe. Therefore, the heat sink 355 is determined according to the configuration efficiency and system stability of the entire cooling system, and the heat sink fin 357 or the heat sink can be selected in shape and size to allow contact with the outside air in a large area. Of course.

That is, when the ball screw 100 rotates, heat is generated by friction with the ball nut 200, and heat is generated by an absorbent plate having a high thermal conductivity embedded between the inner and outer diameter portions of the ball nut 200. This heat is transferred to the heat pipe, and the refrigerant in the evaporation part of the heat pipe 300 vaporizes. Since the vaporized refrigerant gas has a high pressure, and the condensation unit, which is relatively exposed to the outside, is cooled and the pressure is low, the refrigerant gas is moved from the evaporator to the condensation unit.

When the refrigerant gas moves to the condensation unit, the refrigerant gas is condensed again by the temperature of the condensation unit lower than the boiling point exposed to the outside and liquefied. The liquefied refrigerant passes through the wick structure on the inner wall of the heat pipe along the fine passage. Capillary action is to move back to the evaporator. Thus, through the phase shift cycle of the refrigerant to release the friction heat by the high speed rotation of the ball screw and the nut to the outside by the heat pipe having a high heat transfer efficiency, the ball screw 100 and the ball nut 200 by the friction heat It is effective to prevent thermal displacement of).

When the ball nut 200 is generally at or above room temperature, when the temperature is about 50 ° C. or more, a minute thermal displacement occurs, and the thermal displacement causes a problem in system operation, resulting in a problem of lowering productivity. Therefore, the refrigerant used in the present invention preferably has a boiling point of 20 ° C. to 60 ° C., and corresponds to freon, acetone, and the like. That is, it is preferable to measure the temperature at which the thermal displacement occurs in the operation of the ball screw 100 and the ball nut 200 during operation of the machining center, and to adopt the most suitable refrigerant.

In addition, as shown in FIG. 5, the cooling efficiency of the heat pipe 300 is a problem of how well the heat is radiated from the heat dissipation unit. In the present invention, the heat dissipation member 350 including the heat dissipation plate 355 and the heat dissipation fin 357 and The fan is spaced apart at a predetermined interval and faces the front surface of the heat dissipation member 350 to effectively absorb and release heat generated by the heat dissipation member 350 to the outside. Since the speed of the fan is related to the cooling efficiency, it is also possible to control the outside or to automatically control the temperature of the ball screw 100 by measuring it.

As described above, when the cold rolling device of the ball screw assembly proposed in the present invention is provided, the device configuration is much easier and the production cost is lowered than the conventional cooling oil circulation device, and high efficiency and durability can be improved. In addition, there is an advantage that it is possible to prevent the performance degradation due to the oxidation and bearing penetration of the machine tool by the cooling oil is not used.

While the invention has been shown and described with respect to the specific embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Anyone with it will know easily.

1 is a view illustrating a configuration of a cooling device of a conventional conventional ball screw,

Figure 2 is a side view illustrating a configuration of a cooling device of the ball screw assembly according to the present invention,

3 is a front view illustrating a configuration of a cooling apparatus of a ball screw assembly according to the present invention;

4 is a view illustrating a brief configuration diagram of a heat pipe applied in the present invention;

5 is a view illustrating a top view of a chiller structure of a ball screw assembly as a second embodiment according to the present invention.

Description of the main parts of the drawing

100: ball gruck, 200: ball nut, 300: heat pipe, 310: heat absorber,

350: heat dissipation member, 355: heat sink, 357: heat dissipation fin, 400: guide rail,

415: guide, 500: workbench

Claims (12)

delete delete delete delete delete delete A ball screw assembly for converting rotational power of a ball screw shaft into translational power of the ball nut, A heat absorbing part inserted between the outer diameter part and the inner diameter part of the ball nut to absorb heat; A heat pipe extending from the heat absorbing part and configured to be exposed to the outside; A heat dissipation member extending to the condensation portion of the heat pipe; A fan spaced apart from the heat radiating member at a predetermined distance and facing the heat radiating member to dissipate heat generated from the heat radiating member to the outside; A temperature sensor for measuring a temperature of the ball nut; And And a controller for controlling the rotational speed of the fan according to the temperature of the ball nut measured by the temperature sensor. The method of claim 7, wherein The absorber is a cooling device of the ball screw assembly, characterized in that the absorption plate of the cylindrical structure inserted into the outer diameter and the inner diameter of the ball nut. The method of claim 7, wherein And said heat pipe is a plurality of heat pipes extending into said absorbing portion. The method of claim 7, wherein The heat dissipating unit is a cooling device of the ball screw assembly, characterized in that consisting of a heat sink and a heat radiation fin or a heat dissipation wing extending in a direction perpendicular to the heat sink. The method of claim 7, wherein Cooling device of the ball screw assembly, characterized in that the heat dissipation member is attached to the side of the workbench located on the upper surface of the ball nut. delete

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