JPS58146717A - Static pressure guide of hybrid system - Google Patents

Abstract

PURPOSE:To obtain high rigidity in the direction of back component force at cutting, by using at least a largely loaded upper surface of the guide surface of a guide, which guides a moving bed in a machine tool or the like, as the static pressure guide surface and providing a means eliminating static pressure at a machining feed. CONSTITUTION:When a moving bed 2 is quickly fed, solenoid selector valves 29, 30 are opened to feed pressurized air P to each static pressure pocket 20a, 20b, 21c through flow paths 24a-24c and throttles 23a-23c, and a saddle 20 is lifted by static pressure and placed in an almost contactless condition with each guide surface 1a-1c of a guide 1. Under this condition, a feed screw 31 is driven and rotated to quickly feed the saddle 20. Then at a cutting feed, the valves 29, 30 are closed to place the saddle 20 in a boundary lubricating condition of large frictional resistance. While here at machining for a material of high hardness, a solenoid selector valve 27 is selected to both adjust intensity of oil pressure and open a solenoid selector valve 26, then a pressing cylinder 21 is pressed to the surface 1c by the oil pressure to increase rigidity in the direction of cutting back component force.

Description

[Detailed description of the invention] The present invention relates to improvements in static pressure guides for machine tools.

Conventional machine tools, especially the table guide surface of a grinding machine for precision machining, or a boring machine! A static pressure guide is used on the guide surface of a table on which a heavy object such as a steel plate is placed for precise feeding, so as to provide smooth feeding with little frictional resistance. For example, the guide surface of a structure in which the table is placed on the guide surface on the bed and is driven by the feed screw 31 has a large load on the guide 1 as shown in the figure $11.
&, and the inner surface of the movable platform 2 with respect to the narrow guide surfaces 1b and 1c on both sides is designed with a gap between the above-mentioned surfaces and the inner surface, and a static pressure pocket (2 m) on the ceiling, and static pressure pockets 2 on the left and right inner surfaces.
b, 2ci type, pressure fluid passage 4'+ is connected to this static pressure pocket F through throttle 3'+ 3b, 3cTt, respectively.
4 b * 4 c is provided and a static pressure guide is configured which is in communication with a pressure source. However, such static pressure guides have insufficient damping properties against anti-W7J vibrations that reduce frictional resistance, and also have a slight ** on the narrow guide surface.
*Because of this, when processing high-hardness materials, or particularly when processing forces that require precision, the rigidity of the meat is not sufficiently large, which poses a problem.

Therefore, the present invention has been made to solve the above-mentioned drawbacks, and aims to provide a static pressure guide Tt that reduces the load during rapid feed, has high rigidity in the direction of back force during cutting, and has good damping performance against vibrations. According to the first invention, at least the upper surface of the guide surface, which has a large load, is a static pressure guide surface, and a control means is provided to eliminate or weaken the static pressure during machining feed. This is characterized in that the control means is selectively activated.

In addition to the invention of Ill, the invention of Raku 2 is characterized by a mechanism for pressing the movable table against the narrow guide surface when extremely high femaleness in the direction of thrust force is required.

The present invention will be explained below based on the drawings. In the drawing, a guide for an NC lathe is shown as an example, and in FIG. 2, the same parts as in FIG.

On the inner surface of the saddle 20 facing one side of the narrow guide of the guide 1, cylinders 20CTt are bored in preferably two places apart from each other in the width direction, and each cylinder 20CTt opens toward the surface 1. Outside! A single-pressure cylinder 21 of the piston body is slidably fitted into the cylinder 20, and a pressure oil passage 22 is opened at the bottom of the cylinder 20. Oil road 2
2 is connected to a pressure oil source on the source pressure side and on the pressure reduction side via a pressure reduction valve 28 via an electromagnetic switching valve 26 that opens and closes the oil passage and an electromagnetic switching valve 27 that selects two types, for example, strong and weak.
Therefore, when a command is issued from the NC and the electromagnetic switching valve 27 is selected and the electromagnetic switching valve 26 is turned on, high or low pressure oil is sent to the rear surface of the press cylinder 21, causing the front end to pass through the p-guide surface 1. The rigidity is strengthened against the thrust force acting on the pressing saddle 20 during cutting. Further, a static pressure pocket 21& is cut in the center of the pressure field of the pressure cylinder 21, and an annular groove 211m is cut in the outer periphery, which are communicated by a flow path 21c. The annular groove 21b is a diaphragm 2 provided in the drill bit 20.
It communicates with passage 240 via 30. Also, in the pocket for static pressure of koji, 20& -201+ &l:[su251
It communicates with the passages 24 & 24b which communicated via L 2311. The oil passages 24& are connected to a pressure source via an electromagnetic switching valve 29, and the oil passages 2411 and 246 are connected to a pressure source via an electromagnetic switching valve 30. Then, the electromagnetic switching valves 29 and 60 are actuated by a command from the NC, and pressurized fluid, in this example, pressurized air, is supplied to each static pressure pocket in response to a rapid feed command, and is shut off in response to a cutting feed command. Furthermore, the narrow guide surface 1b
- Static pressure pockets 2'5b and 23 for 10 (pressurized air to 1 is controlled so as to be supplied only when necessary).

Now, with a fast forward command from the NC, the electromagnetic switching valve 29.! 10 opens and pressure air flows through the flow paths 24 & 24b and 24 (+ throttle 231
・Each static pressure pocket 26 & 2 via 231 and 230
When sent to 3b and 23o, the saddle 20 is lifted by static pressure and each image is! Be left in a no-contact state. Based on the signal detected by this static pressure and the fast-feeding command signal, a not-shown seat motor rotates the feed screw 31 to rapidly feed the saddle 20. Next, the solenoid switching valves 29 and 60 are
is closed, the pressure air is cut off, the static pressure tm is reduced, and a boundary lubrication state with large frictional resistance is created.At the same time, the feed screw 31 is not switched to cutting feed and the dollar 20 is fed by cutting. When the material to be processed is a high-hardness material, the saddle 20 receives a large cutting thrust force, so the electromagnetic switching valve 27 is selected according to the material specification at the same time as the cutting feed command, and the strength of the utility oil is determined. is fought, pressure oil is sent to the cylinder 20 (l) via the oil passage 22, the press cylinder 21 is pushed out, the narrow guide surface 1at is pressed, and the f dollar 20 clamps the narrow guide surfaces 1b and 1C. The directional stiffness is increased to the required magnitude.

Next, 1113. which shows an example of II2. In the 4th H, the saddle 20 is not provided with a mechanism for holding the suta-X side, and the narrow guide wjj1b.1@It)Ill. jib or roller guide or &-
The guide 25111 is built in so that it can be adjusted in increments, and along the narrow guide ail 1@, grooves 20 straight for blowing out air from the static pressure groove 20a are cut in the vertical direction, and static pressure is applied during rapid cutting. It is the same that pressurized air is shut off so that static pressure 1e does not occur during feeding. This is primarily intended to reduce the load during rapid forwarding.

Furthermore, in the example of the 1,112th edition, if air supplemented with a small amount of lubricating oil is used in combination with the compressed air for static pressure, efficient lubrication of the sliding motion can be obtained, and loss and dirt caused by dripping of the spear can be prevented. can.

Furthermore, the magnitude of the pressure air for static pressure can be selected by an electromagnetic switching valve, so that the static pressure t-W4 can be kept unchanged. In this case, it is also possible to mix lubricating oil during cutting and feeding to prevent seizure, etc. As a means for eliminating or reducing the static pressure, it is also possible to provide a control means for releasing and weakening the pressure in the static pressure pocket.

As described in detail above, the present invention uses a control means to create a static pressure guide in which static pressure is applied at least to the upper surface with a large load during rapid traverse, and no or weak static pressure is applied during cutting feed. N [4 or more widths can be reduced and the moving platform can be moved at high speeds.
It is possible to eliminate the need to increase Il. In addition, the rigidity in the direction of back force during cutting feed is increased, and vibration damping properties are provided, allowing precision feed to be performed during precision machining play, improving the finish of the machined surface, and improving product quality. Hold the moving platform p-guide *W
This feature provides sufficient rigidity even against large thrust forces when cutting high-hardness materials.

[Brief explanation of the drawing]

@Figure 1 is a sectional view of a conventionally known static pressure guide. Figure 2 is a sectional view of a static pressure guide of the present invention. Figure 3 is a sectional view of the second embodiment. Figure 4 is a perspective view of the ts2 embodiment. It is a diagram. 1...Guide 1b/1C...Narrow guide 2-
20 ・-Moving platform 2m -2b -20-2oa2
0b・200... Static pressure pocket 21... Press cylinder 25... Jib or rolling gully guide 26, 27, 29, 60... Solenoid switching valve assembly 21
A

Claims (1)

[Scope of Claims] (1) In the id of a machine tool that guides a moving pedestal on which a workpiece or a turret or the like is placed and is sent by a drive device, the id of the machine tool is placed at least on the id surface that receives the maximum load. A pocket for static pressure is provided in the sliding movement of the cage and communicated with a source of pressure fluid through a restriction, and a control means is provided for eliminating or weakening the static pressure generated within the cage by supplying pressure fluid in accordance with a processing feed command. The static pressure guide is a vibration lift type static pressure guide in which the static pressure is applied selectively during rapid feed and machining feed. (The pressure fluid is air mixed with a small amount of lubricant. In the guide of the machine tool to be guided, at least the guide surface receiving the maximum load is provided with an aperture (static pressure pocket passed through the pressure fluid source and 1!!) in the sliding motion of the moving table against which the pressure fluid is supplied. The static pressure generated in the pocket due to feeding is eliminated or slightly reduced by the processing feed command.
A control means is provided to act on the movable table side with respect to the narrow guide side which is a part of the guide, and a suppressing means is provided which acts on the movable table side with a pressure fluid, so that the static pressure is selectively applied during rapid feed and machining feed, and when necessary. 7. A hybrid type static pressure guide, characterized in that the pressing means acts so as to increase the rigidity during machining accordingly. (4) Pressure fluid is air mixed with a minute amount of water.
Il#Claims I#Il The hybrid type static pressure guide according to claim 6.