JPS59227352A - Cooling device of ball screw mechanism - Google Patents

Abstract

PURPOSE:To minimize an amount of fluid required for cooling a ball screw mechanism so as to simplify its control circuit and control mechanism, by constituting a device such that a valve for supplying the fluid to the ball screw mechanism is controlled by using a signal output from an NC device. CONSTITUTION:Driving power generated by a motor 1 driving a ball screw mechanism 25 is transmitted to a ball screw 3. While a ball nut 16 is mounted to a threaded part 4 of the screw 3. Next, air fed from a unit is once stored in a tank and supplied to the mechanism 25 through a hose 24 when a valve is opened. while an NC device controlling the motor 1 outputs a signal of normal or reverse motor rotation, normally or reversely rotating the motor 1 in accordance with the programmed control information. By this constitution, the amount of fluid necessary for cooling the ball screw mechanism is minimized, and its control circuit and control mechanism can be simplified.

Description

[Detailed description of the invention]

This invention effectively ensures the accuracy of the ball screw by efficiently discharging the heat generated when driving the ball screw mechanism installed in various machine tools to the outside of the ball screw mechanism and preventing thermal expansion of the ball screw mechanism. This invention relates to a cooling device for a ball screw mechanism that can be driven at high speed. In recent years, in sheet metal processing machines such as punch presses, there is 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 pole nut is used to position the workpiece. Many of them are designed to do this 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 pole 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. Therefore,
It may be possible to suppress the temperature rise of the ball screw mechanism by feeding a room temperature or pre-cooled fluid (for example, a gas such as air or a liquid such as oil) into the ball screw mechanism, but in this case, it is necessary to constantly supply this fluid. A large amount of fluid is required to cool the ball screw mechanism of the cigarette (and there is a problem that the ball screw mechanism may be cooled too much). However, the control circuit and control mechanism thereof are complicated.In view of the above points, the present invention is capable of minimizing the amount of fluid required for cooling the ball screw mechanism, and also provides a method for cooling the ball screw mechanism. It is an object of the present invention to provide a cooling device for a ball screw mechanism that can prevent overheating and also simplify its control circuit and control mechanism. To achieve this purpose, the cooling device controls the valve that supplies fluid to the ball screw mechanism using signals output from an NC device that controls the rotation of the ball screw when the ball screw is rotating. It is characterized by the fact that it is made to do so. The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is a sectional view showing an embodiment of a cooling device for a ball screw mechanism according to the present invention. In this figure, reference numeral 1 denotes a motor that drives this ball screw mechanism 25, and the driving force (rotational force) generated by this motor 1 is transmitted to the ball screw 3 via a driving force transmission fitting (force/amplifier) 2. The ball screw 3 has a main body (threaded part) 4 in which a thread is formed, and inner rods 5 and 6 provided at both ends of the main body 4, and one of the inner rods 5 is connected to the power transmission fitting 2. and is supported by a bearing bracket 8 via a bearing 7, and the other inner rod 6 is supported by a bearing bracket 10 via a bearing 9, and the one inner rod 5 is supported by an end of the inner rod 5. The nut 12.13 and the bearing bracket 8 &
Axial positioning is performed by the bearing stop 14°J5 provided here. Further, the threaded portion 4 of the ball screw 3 is equipped with a ball nut]6
is installed, and when the ball screw 3 rotates, this rotation t corresponds to this rotation t. The guide shaft shown in FIG. Here, a fluid passage 19 penetrating from the upper surface of the moving table 17 to the upper surface of the ball nut 16 is formed, and a circumferential groove 20a along the outer circumferential surface 16a of the pole nut 6 is formed at the lower end of the fluid passage 19. 20b and these circumferential grooves 20a. a gap joint groove 21a that connects the upper and lower ends of 20b, respectively;
21b (see the partial sectional view taken along line B-B in FIG. 1 shown in FIG. 2(B)) is formed.
A discharge port 22 is formed at the bottom of the oa, and a fluid at room temperature or cooled (for example, air, carbon dioxide, , a gas such as nitrogen, or a liquid such as oil), this fluid is supplied into the circumferential groove 208° 20b through the plug 23 and the fluid passage 19 in order, Therefore, if all the fluid is supplied from the hose 24 according to the heat generation of the ball screw mechanism 250 composed of the ball screw 3 and the pole nut 6, the temperature of the ball screw mechanism 25 will be lowered. The control circuit for controlling the amount of fluid fed will be explained below by taking the circuit of a normal temperature air supply mechanism as an example. Fig. 3 is a block diagram showing an example of this control circuit. In the figure, 30 is an air intake port, and the air taken in from this air intake port 30 is a unit (3 points set)).
3]. The unit 3 consists of a filter 32 that removes dust from the air, a pressure reducing valve 33 that makes the air coming out of the filter 32 a desired pressure, and an oiler 34 that mixes oil mist into the air from the pressure reducing valve 33. The air coming out of this unit 31 is temporarily stored in a tank 35, and when the valve 36 is opened, the air is discharged from the port 2 shown in FIG.
4 to the ball screw mechanism 25. Further, 37 is an NC device (numerical control device) that controls the motor 1, and the control information shown in FIG.

[The motor normal rotation signal s1 shown in the figure is output to rotate the motor 1 in the normal direction, and the reverse rotation signal s2 shown in the figure (b) is outputted to reverse the motor 1. A valve opening signal S3 synchronized with is output to open the valve 36. Therefore, if the ball screw mechanism 2 is driven by rotating the motor 1 in the forward or reverse direction, air is sent out from the valve 36 and cooling of the ball screw MFL 125 is started, and if the motor 1 stops thereafter, the valve 3
6 is closed, and cooling of the ball screw mechanism 25 is stopped. In this embodiment, the ball screw mechanism 25
Taking advantage of the fact that the amount of heat generated is proportional to the drive period, fluid is sent to the ball screw mechanism 25 in an amount corresponding to the drive period, so when the ball screw mechanism 25 generates heat, this heat is It is possible to remove just the right amount and keep the ball screw mechanism 25 at the optimum temperature. In this case, the valve opening signal S3 may be obtained by ORing the signals Sl and S2, or may be obtained by detecting the rotation of the motor 1 with a sensor or the like. Further, in this embodiment, the valve opening signal S3 outputted from the NC device 37 is directly used to control the valve 36, but as shown in FIG. ) is supplied to the fall delay circuit 38, and this valve opening signal s3 is supplied as shown in FIG.
The rise of the valve is delayed by a period d, the resulting valve opening signal S4 is supplied to the valve 36, and the period during which the valve 36 is in the open state is lengthened. For example, when the ball screw mechanism 25 is driven at a high speed and generates a large amount of heat, the ball screw mechanism 25 can be sufficiently cooled.Furthermore, without using the method of prolonging the open state of the valve 36, , valve 36
The flow rate may be reset and the lever valve 36 may be throttled so that air is sent in an amount corresponding to the level of development of the ball screw mechanism 250. Furthermore, as shown in FIG.
It may be configured so that it is a part of it. In this case, the air to be supplied is fed into the circumferential groove 29 formed in this way (the air is supplied through the cylindrical gap 40 formed at both ends of the circumferential groove 290).
, 4] are discharged to the outside. Furthermore, in each of the above-mentioned embodiments, air at room temperature is transferred to the ball screw mechanism 2.
5, but this air may be cooled in advance. In addition, in the explanation so far, this invention has been explained by taking as an example the case where air (gas) is sent to the ball screw mechanism 25, but the fluid controlled by the valve 36 may be a liquid such as oil at room temperature or cooled. Compressed air may also be used. However, in the case of compressed air, it goes without saying that an expansion mechanism is provided on the ball screw mechanism 25 side to adiabatically expand the air and lower its temperature. Next, a turret press device to which the ball screw mechanism equipped with a cooling device according to the present invention is applied will be described. FIG. 8 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 is used in the first embodiment or the second embodiment described above.
Ball screw mechanisms 32-d and 32-e as shown in the embodiment
These ball screw mechanisms 32d and 32-e position the sheet metal (workpiece) 45, and the turret punch press section 46 presses the sheet metal 4.
When the ball screw 4-d is rotated by one power source]-d on the base 2, the first moving table 23-d and this moving table 23 are pressed.
-d (on which the second moving table 23-e is placed)
moves in the X direction (or -X direction), and the first
When the ball screw 4-e is rotated by the other power source]-e on the movable table 23-d, only the second movable table 23-e is rotated in the Y direction (
(or in the -Y direction). By energizing the positioning servo power source ]-d, l=e according to the work data, the workpiece 45 fixed to the second moving table 23-e can be moved in the X direction, Y direction (or -X direction, -Y direction) to position the workpiece 45 tx
This can be pressed by the turret press section 46. And in this case this workpiece 45
The ball screw mechanisms 32-d and 32-e for moving the ball screw 4 are cooled by the cooling device according to the present invention.
i! ! Even if the structures 32-d and 32-e generate heat, the temperature rise is prevented, and errors caused by thermal expansion are prevented. 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 ball screw mechanism cooling device according to the present invention controls the fluid feeding period in accordance with the driving period of the ball screw mechanism, so that the ball screw mechanism can be cooled with the minimum amount of fluid. In addition, it is possible to prevent the ball screw mechanism from being overcooled or insufficiently cooled, and it is also possible to simplify the circuit that controls the fluid.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a cooling device for a ball screw mechanism according to the present invention, and FIGS. 3 is a block diagram showing an example of the circuit configuration of this embodiment, FIG. 4 is a waveform diagram for explaining this block diagram, and FIG. 5 is a block diagram showing another example of the circuit configuration of the present invention. FIG. 6 is a waveform diagram for explaining this block diagram, FIG. 7 is a sectional view showing another embodiment of the present invention, and FIG. 8 is a turret press to which a ball screw mechanism equipped with a cooling device according to the present invention is applied. FIG. 2 is a perspective view of the device. J...Motor, 3...Ball screw, 16...Ball nut, 19...Fluid passage, 20a, 20b, 29...
Circumferential groove, 25...Ball screw mechanism, 36...Valve, 3
7... NC device (valve control means), 38... Fall delay circuit (valve control means). Patent Applicant Anritsu Electric Co., Ltd. Agent Patent Attorney Norimitsu Nishimura Procedural Amendment (Method) Director of the Japan Patent Office Kazuo Wakasugi, 1965/1989 Patent Application No. 102903 2 Title of the invention: Cooling device for pole screw mechanism 3 Relationship with the person making the amendment Patent applicant (057) Anritsu Electric Co., Ltd. 4 Agent: 105 5 Date of amendment order: September 7, 1982 (Date of dispatch: 1982) September 27) 6 Subject of amendment Drawing 7 Contents of amendment

Claims (1)

[Claims] Cooling of the ball screw mechanism that cools the ball screw mechanism by supplying fluid to the ball screw mechanism that rotates the ball screw to linearly move a ball nut attached to the ball screw and linearly move a moving table attached to the pole nut. A valve control means that outputs a valve open signal when the ball screw is rotating, and outputs a valve close signal when a desired time including zero has elapsed since the ball screw stopped rotating; A cooling device for a ball screw mechanism, comprising: a valve for supplying fluid to the ball screw mechanism from when the control means outputs the valve open signal to when the control means outputs the valve close signal.