JPH0434025B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention prevents thermal expansion of the ball screw mechanism by efficiently discharging heat generated when driving the ball screw mechanism installed in various machine tools to the outside of the ball screw mechanism. The present invention relates to a cooling device for a ball screw mechanism that ensures sufficient accuracy of the ball screw and thereby enables high-speed driving.

In recent years, in sheet metal processing machines such as punch presses, there has been a strong demand for high precision processing in order to reduce processing costs, so a ball screw mechanism consisting of a ball screw and a ball nut is used to position the workpiece. In many cases, this is done at high speed.

When such a ball screw mechanism is rotated at high speed, it generates a large amount of heat, raising the temperature of the ball screw mechanism, causing thermal expansion in the ball screw and ball nut, and reducing their positioning accuracy. Therefore, it is not possible to simultaneously satisfy both high-speed positioning and high-precision positioning unless this reduction in accuracy due to heat generation is resolved.

In view of the above-mentioned circumstances, this invention provides safety and security that even when a ball screw is rotated at high speed to perform high-speed positioning operation, the heat generated at this time can be removed at the generating part to achieve high-precision positioning. The object of the present invention is to provide a ball screw mechanism cooling device that is also easy to handle.

The structure of the present invention to achieve the above object is as follows.

That is, the present invention provides a ball screw mechanism that linearly moves a moving table attached to the ball nut 17 by linearly interlocking the ball nut 17 attached to the ball screw 4 by rotating the ball screw 4. A cylindrical hole is provided continuously along the outer circumferential surface of the ball nut 17 between the outer circumferential surface and the inner circumferential surface of a hole provided in the movable table for fitting and attaching the ball nut 17 to the movable table. It also includes a closed air space for introducing and storing external gas, a gas passage that guides gas for cooling the ball screw mechanism from the outside of the moving table to the air space, and discharging the gas to the outside from the air space. A cooling device using a ball screw mechanism is characterized in that the cooling device is equipped with an exhaust port for water and water.

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 is a sectional view showing an example of a ball screw mechanism to which an embodiment of the cooling device according to the present invention is applied. In this figure, 1 is a positioning servo power source provided on a base 2, and the driving force generated by this positioning servo power source 1 is transmitted to a ball screw 4 via a power transmission coupler 3. Ru. The ball screw 4 has a circular rod part 5 for mounting a bearing, a threaded part 6 for a bearing fixing nut, and a mounting part 7 for a power transmission fitting coaxially at the end on the side where the power source 1 for the positioning servo is provided. The mounting portion 7 of the ball screw 4 is connected to the coupler 3, and the circular rod portion 5 is supported by a first support portion 8. The support portion 8 includes a bracket 10 fixed to the base 2 by set screw portions 9, 9, . . . , a bearing 11 fitted into the bracket 10, and a bearing for fixing the bearing 11 to the bracket 10. It has fixing fittings 12, 12, setscrews 13, 13 for connecting the bearing fixing fittings 12, 12 and the bracket 10, and nuts 48, 48 for fixing the ball screw 4 and the bearing 11, The ball screw 4 is rotatably and securely positioned by the support portion 8.

On the other hand, at the end of the ball screw 4 opposite to the positioning servo power source 1, the above-mentioned circular rod portion 5 is provided.
A bracket 10 is formed in which a circular rod portion 14 for mounting a bearing similar to the above is formed, and this circular rod portion 14 is fixed to the base 2 with setscrews 9b, 9b...
b and a bearing 11b fitted into this bracket 10b.

On the other hand, a ball nut 17 holding a large number of balls is attached to the threaded portion 16 of the ball screw 4 constructed as described above. The ball nut 17 is attached to the moving table 23 via a ball nut bracket 22 and fixed with setscrews 31, 31, . . . .

As shown in the cross-sectional view of FIG. 2 (this cross-sectional view is taken along line B-B in FIG. 1), the movable table 23 has brackets 33, 33, . . . for guide bearings formed on both sides thereof. The guide shaft 3 on the guide bearings 35, 35 provided on the base 2 by the guide bearings 34, 34 fitted into these brackets 33, 33, respectively.
6 and 36 in a slidable manner. In this case, as shown in FIG. 1, these guide bearings 34, 34...
7... are respectively fixed to the brackets 33, 33....

Further, the bracket 22 has a width W and a depth h at a portion in contact with the outer circumferential surface 18a of the ball nut 17.
The circumferential grooves (gaps) 24a and 24b are formed, and the sectional view shown in FIG.
- As shown in the partial cross-sectional view taken along the line A, gap joint grooves 25a and 25b are formed to communicate these circumferential grooves 24a and 24b, and furthermore, on the lower end side, the one circumferential groove 24a and the outside are connected. A gas passage 27 passing through the bracket 22 and the moving table 23 is formed in the upper part of the other circumferential groove 24b, and this gas passage A plug 28 for gas injection is screwed into the upper part of 27. The plug 28 is provided with a socket 29 on its side for attaching a gas hose, and this socket 2
A hole for a gas passage is bored from 9 to the threaded portion thereof, and gas can be sent into the gas passage 27 via a hose 30 connected to the socket 29.

As described above, in this embodiment, the bracket 22 is formed with circumferential grooves 24a, 24b surrounding the outer peripheral surface 18a of the ball nut 17 and gap joint grooves 25a, 25b that connect these grooves, and the upper part of one of the circumferential grooves 24b is formed. gas passage 27
The hose 30 of the plug 28 in the upper part of the gas passage 27 and the circumferential groove 24b are connected to each other, and the discharge port 26 is formed in the lower part of the circumferential groove 24a.
Since the circumferential groove 24a and the external space are communicated with each other, when a room temperature or cooled gas such as air, carbon dioxide, nitrogen, etc. is sent from the hose 30, this gas is released into the plug. 28, passing through the gas passage 27 in sequence to form the circumferential grooves 24a, 24.
b, where it removes heat from the ball nut 17 and ball screw 4, and then is discharged to the outside from the discharge port 26. Therefore, when the ball screw mechanism 32 composed of the ball screw 4 and the ball nut 17 generates heat, it can be cooled simply by feeding gas from the hose 30. Moreover, in this case, if the temperature of the gas sent from the hose 30 is at or near room temperature, the ball screw mechanism 32 will not fall below room temperature even if a large amount of this gas is supplied into the circumferential grooves 24a, 24b. Regardless of whether or not the ball screw mechanism 32 generates heat, the ball screw mechanism 32 can be kept at an optimal temperature by simply feeding gas at all times.

Further, the pre-cooled gas is supplied to the circumferential grooves 24a and 24b.
If you feed it into the ball screw mechanism 32
Even when the amount of heat generated is large, this heat can be discharged to the outside of the ball screw mechanism 32 to prevent the temperature from rising. Moreover, in this case, by changing the cooling temperature of the gas according to the amount of heat generated by the ball screw mechanism 32, the temperature of the ball screw mechanism 32 can be made to be the optimum temperature without changing the amount of gas fed too much. Further, the circumferential groove 2
4a, 24b and the gas passage 27 are connected to the bracket 2.
2. Since the movable table 23 and the ball nut 17 are formed in parts where heat is likely to accumulate, the heat generated by the ball screw mechanism 32 is efficiently transferred to the gas passing through the gas passage 27 and the circumferential grooves 24a and 24b. Therefore, the ball screw mechanism 32 can be efficiently cooled. Furthermore, in the embodiment described above, the upper and lower ends of the circumferential grooves 24a and 24b are joined by the gap joint grooves 25a and 25b, and
Since the discharge port of the gas passage 27 is located directly above one of the circumferential grooves 24b, the gas discharged from the gas passage 27 is divided into two at the upper part of these circumferential grooves 24a and 24b.
One of them can be led to the discharge port 26 along the outer circumferential surface 18a on the back side (the back side in the figure) of the ball nut 17, and the other one can be guided to the discharge port 26 along the outer circumferential surface 18a on the near side of the ball nut 17. This ball nut can lead to 1
7 and the ball screw 4 can be evenly cooled from the surroundings.

Further, in this embodiment, the circumferential grooves 24a, 24
Although the gas sent into b is directly discharged to the outside from the discharge port 26, a hose is attached to this part to guide the gas discharged from these circumferential grooves 24a and 24b to a predetermined location and release it. Alternatively, it may be used again after being supplied to a heat radiator to radiate heat.

Next, a turret press device, which is one of the devices to which the ball screw mechanism equipped with a cooling device according to the present invention is applied, will be described.

FIG. 4 is a perspective view of a turret press equipped with a cooling device according to the present invention. As shown in this figure, this turret press device 44 has ball screw mechanisms 32-d and 3 as shown in the above-mentioned embodiment.
2-e are arranged perpendicular to each other, a sheet metal (workpiece) 45 is positioned by these ball screw mechanisms 32-d and 32-e, and the sheet metal 45 is pressed by the turret bunch press section 46. When the ball screw 4-d is rotated by one power source 1-d on the table 2, the first moving table 23-d and the second moving table placed on this moving table 23-d are rotated. The table 23-e moves in the X direction (or -X direction), and
The other power source 1 on the moving table 23-d of
If the ball screw 4-e is rotated by -d,
Correspondingly, the second moving table 23-e
The only movement is in the Y direction (or -Y direction).

Therefore, if the positioning servo power sources 1-d and 1-e are energized according to the work data, the second
The workpiece 45 fixed to the moving table 23-e is moved in the X direction, Y direction (or -X direction, -
The workpiece 45 can be positioned by moving it arbitrarily in any direction (Y direction),
This can be pressed by the turret press section 46. In this case, the ball screw mechanisms 32-d and 32-e that move the workpiece 45 are cooled by the cooling device according to the present invention, so even if the ball screw mechanisms 32-d and 32-e generate heat, their temperature is prevented from rising. This prevents errors caused by thermal expansion. Thereby, it is possible to simultaneously satisfy both high-speed positioning and high-precision positioning of the workpiece 45, and it is possible to reduce machining costs and increase machining speed.

As explained above, the cooling device for a ball screw mechanism according to the present invention has an airtight air space continuously formed in a cylindrical shape along the outer peripheral surface of the ball nut between the ball nut and the movable table constituting the ball screw mechanism. By supplying gas, heat is radiated from the entire outer periphery of the ball nut, where heat is concentrated, so that cooling can be achieved on or within the walls of ball nuts and ball screws, which are precision parts that have reciprocating grooves for guiding the balls on each of their contact surfaces. There is no need to process media passages, etc., standard ball screws and ball nuts with excellent strength and precision can be used, and the structure is relatively simple and easy to manufacture and adjust, allowing efficient heat generation. becomes. In addition, the cooling gas blows off the lubricating oil around the ball screw,
It is possible to prevent the temperature of the ball screw mechanism from rising even when the ball screw is rotated at high speed without causing any adverse effects due to expansion and contraction of the entire ball screw, and it is possible to configure high-speed positioning and high-precision positioning at the same time. .

In addition, the air between the outer periphery of the ball nut and the mounting part of the moving table, to which cooling gas is supplied, is a closed air with a relatively small capacity that is continuously formed in a cylindrical shape along the outer periphery of the ball nut. 〓, the pressure, flow rate, and temperature of the cooling gas can be freely set, resulting in good cooling efficiency and easy adjustment.

In addition, since gas is used as the cooling medium, it is easy to discharge and dispose of, and it can be easily fitted onto an existing ball screw mechanism, and there is no risk of fire like those that use oil as the cooling medium. It also has excellent effects in terms of safety.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a ball screw mechanism to which an embodiment of the cooling device according to the present invention is applied, FIG. 2 is a sectional view taken along line B-B in FIG.
FIG. 4, a cross-sectional view taken along line -A, is a diagram showing an example of a turret press device to which a ball screw mechanism equipped with a cooling device according to the present invention is applied. 4...Ball screw, 17...Ball nut, 2
1... Ball, 22, 22-b... Bracket (connection fitting), 23, 23-b, 23-d, 23-
e...Moving table, 24a, 24b...Peripheral groove (gap), 27, 27-b...Gas flow path, 32,3
2-b, 32-d, 32-e... Ball screw mechanism.

Claims (1)

[Scope of Claims] 1. By rotating the ball screw 4, the ball nut 17 attached to the ball screw 4 is rotated.
In a ball screw mechanism that linearly moves a moving table attached to the ball nut 17 by linearly interlocking the ball nut 17, the outer peripheral surface of the ball nut 17 and a hole provided in the moving table for fitting and attaching the ball nut 17 to the moving table. an airtight air hole for introducing and storing external gas, which is continuously provided in a cylindrical shape along the outer peripheral surface of the ball nut 17 between the inner peripheral surface of the ball nut 17 and the gas for cooling the ball screw mechanism. A cooling device for a ball screw mechanism, characterized in that the cooling device comprises: a gas passageway for guiding gas from outside the movable table to the air space; and an exhaust port for discharging the gas from the air space to the outside.