JPH0141468B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a feeding device for a machine tool, and relates to a feeding device for a machine tool, which allows moving parts of the machine, such as a work table and a spindle head, to be moved with high precision and high speed relative to a fixed base of the machine. The present invention relates to a feeding device for a machine tool that can feed and move.

[Prior art]

Feeding devices for machine tools have conventionally adopted various configurations, and usually a feeding mechanism is formed by a combination of a feed screw and a nut meshed with the feed screw, and the feed screw is driven by a drive motor such as a servo motor. By rotating the nut in forward and reverse directions, the moving body connected to the nut is moved straight in a desired axial direction.

Furthermore, JP-A No. 55-150951 eliminates the above-mentioned combination of the feed screw and nut, and provides rolling rollers that are pressed against both sides of a long rail-shaped friction plate. A feeding device for a machine tool is disclosed in which the rolling rollers are separately attached to a base and a moving body, and the rolling rollers are driven by a drive motor through gears to cause the moving body to move in a straight line.

[Problem to be solved]

However, in the case of a feed device having the former combination of a feed screw and a nut, the inertia load of the feed screw applied to the drive motor is large, and backlash cannot be avoided, so the servo gain in the feed device cannot be increased. There is an inconvenience in that the cutting feed rate is limited when machining curves or corners of workpieces, and when trying to extend the straight stroke, twisting of the feed screw occurs, which adversely affects the feed accuracy.

In addition, the latter feeding device has a structure that allows either the friction plate or the rolling roller to be elastically displaced in a direction perpendicular to the direction of movement even when the straight stroke is long, thereby solving the above-mentioned drawbacks of the former. However, since a gear mechanism is interposed between the drive motor and the rolling roller, the structure becomes complicated.

Therefore, it is an object of the present invention to provide a feeding device for a machine tool that takes advantage of the latter advantage described above and has an improved and simplified structure.

[Means of solution and action]

In order to achieve the above-mentioned object, the present invention includes a longitudinal guide rail attached to either a fixed base of a machine or a moving body according to the feed length, and at least a longitudinal guide rail that rolls and engages with both sides of the guide rail. A rolling unit consisting of a pair of driving rollers and a pressing roller, a motor that drives the driving roller via a flexible joint, pressing pressure setting means built into the rolling unit, and a rolling unit that controls the rolling unit in the feeding direction. and a flexible coupling means that is attached to the movable body or the fixed base while being held for slight movement only in the vertical direction, and is configured to feed and move the movable body according to the forward and reverse rotation of the motor. We provide machine tool feeding devices that are characterized by the following:
A flexible joint inserted between the drive roller and the motor, and a flexible coupling means for coupling the rolling unit to the movable body or the fixed base allow the connection between the guide rail and the drive and pressure rolls without requiring the intervention of a gear mechanism. This enables friction rolling. Hereinafter, the present invention will be explained in more detail based on embodiments shown in the accompanying drawings.

〔Example〕

FIG. 1 is a longitudinal cross-sectional view showing a structure in which a rolling unit is coupled to a fixed base and a guide rail is movable together with a moving body of a machine, as an embodiment of a feed device for a machine tool according to the present invention. A side view of the rolling unit of the device shown in FIG.
FIG. 3 is a cross-sectional view taken from the arrow direction - in FIG. 1.

1 to 3, the fixed base 10 forms the stationary part of the machine relative to the movable body 12, for example, the bed is relative to the saddle, the saddle is relative to the table, and the column is relative to the spindle head. It forms a moving body relative to a fixed base. In FIG. 1, the movable body 12 is connected to the fixed base 1.
An example is shown in which it is possible to move in a direction perpendicular to the plane of the paper with respect to 0, and therefore a straight guide 14 is provided between the two. The fixed base 10 has a bracket 18 attached to the upright portion 16, and the bracket 18 has a projecting plate 18a projecting above the fixed base 10. 20 is a threaded bolt for fixing the bracket 18 to the upright portion 16. The feeding device provided between the fixed base 10 and the movable body 12 has a guide rail 22.
is formed as a long member extending in the moving direction of the movable body 12, and both ends are integrally connected to the movable body 12 by appropriate fixing means 24, 26, as shown in FIG. That is, in this embodiment, the guide rail 22 is also provided as a moving member. This guide rail 22 is made of a metal rod or has excellent wear resistance.
It is formed of a rod material such as ceramics which has little thermal deformation, and both sides thereof are formed into mutually parallel friction surfaces on which the driving roller 28 and the pressing roller 40 roll against each other. The drive roller 28 is held at both ends by supports 30, 32, is rotatably supported by rotary bearings 36, 36 held in a roller housing 34, and the support 32 at one end is connected to the lower part of the shaft coupling. It is wedged and fixed to the flange 38.

On the other hand, the pressing roller 40 is pressed against the friction surface of the guide rail 22, and the pressing roller 40 is pressed against the rotating shaft 4.
2 by press-fitting or the like. Both ends of the rotating shaft 42 are rotatably supported by rotating bearings 46, 46 held in a roller housing 44. As clearly shown in FIG. 3, the roller housing 34 of the driving roller 28 and the roller housing 44 of the latter pressing roller 40 are connected by a plurality of threaded bolts 52 via a hole G, and a disc spring 54 is inserted. This creates a strong connection between the two. That is, the driving roller 28, the pressing roller 40, the roller housings 34, 44, etc. constitute a rolling unit. As shown in FIG. 1, this rolling unit consists of a pair of leaf springs 48, 50.
It is connected to the protruding plate 18a of the bracket 18 by using suitable screw means. Therefore, the two leaf springs 48, 50 are used as flexible coupling means to couple the rolling unit to the bracket 18 which is integral with the fixed base 10. In addition, both leaf springs 48, 50 and both roller housings 34, 44
The connection is fixed with screws via a contact plate 56. It is preferable that the portion of the drive roller 28 in the above-mentioned rolling unit that comes into pressure contact with the guide rail 22 be made of a material with excellent wear resistance, and therefore a metal material or a material such as ceramics is selected. Similarly, it is preferable that the pressing roller 40 is also made of a material such as ceramics. The rollers 28, 40 are pressed against both side surfaces of the guide rail 22 without slipping, and are provided so as to sandwich the latter.

Now, the above-mentioned rolling unit includes the leaf spring 48,
Although it is provided so that it can be bent in a direction perpendicular to the feeding direction due to the flexible elasticity of 50, it is mounted so as to have high rigidity in the feeding direction. Further, the lower flange 38 of the drive roller 28 described above is connected via a flexible joint 60 to an upper flange 58 which is wedged and fixed to the output shaft of the drive motor M. That is, in this embodiment, the flexible joint 60 is formed by a bellows disposed in the through hole of the protruding plate 18a, and both ends of the bellows are connected to the upper and lower flanges 58, 38, respectively. The rotational output of the drive motor M is precisely transmitted to the drive roller 28, and at the same time, the rotation axis is formed to be flexible at a flexible joint 60 made of bellows. By providing the flexible joint 60 in this manner, in conjunction with the flexible structure of the leaf springs 48 and 50 forming the flexible coupling means of the rolling unit described above, when the driving roller 28 and the pressing roller 40 roll, Even if a bend occurs on the long guide rail 22 side, the bend is absorbed by the flexible joint 60 and the flexible coupling means, and the movement in the straight direction is not affected at all, allowing smooth straight movement. It enables movement. It should be noted that the flexible coupling means formed by the leaf springs 48 and 50 maintains rigidity in the straight direction and prevents errors in the feeding operation.

The operation of the feeding device having the above-mentioned structure is that the driving roller 2 of the rolling unit is moved through the driving motor M.
8, the driving roller 28 presses and clamps the guide rail 22 together with the pressing roller 40, so that a linear action is applied to the guide rail 22 due to the frictional force on the pressing surface, and the guide rail 22 is rotated.
2, the moving body 12 moves in a straight line. Of course, if the drive motor M is formed by a servo motor, the moving body 12 can be moved by a desired amount in a desired axial direction, for example, in the X-axis direction, by controlling the rotation speed and rotation direction of the servo motor. Works, tools, etc. on the moving body 12 can be positioned at desired positions. Further, contrary to the above-described embodiment, the guide rail 22 may be properly fixed to the fixed base 10, and the bracket 18 to which the drive motor and rolling unit are attached may be coupled to the movable body 12. Same as in the example. The flexible joint 60 may be a commercially available helical flexible joint instead of the bellows of this embodiment.

〔Effect of the invention〕

As is clear from the above description, the present invention forms a feeding device in which a guide rail and a rolling roller are distributed and attached to a fixed base and a moving body, and furthermore, the guide rail and the rolling roller are connected to a fixed base and a moving body through a flexible joint. In addition to being axially coupled, the rolling unit maintains high rigidity in the straight direction of the moving body, while providing a flexible structure with flexible coupling means in the direction that intersects with the straight direction.
Feed along the guide surface was obtained without applying unreasonable force to the movable body, and a highly accurate feed device was obtained. Additionally, since we were able to form a simple motion transmission mechanism without any gear mechanism within the feeder, the inertia load on the drive motor can be reduced compared to a feeder with a conventional feed screw-nut combination structure. Moreover, an advantageous effect was obtained in that the inertia load did not increase even if the feed length was increased. In addition, since there is no backlash caused by screws or gears, it is possible to increase the gain of the servo system and configure a high-speed feed system. Furthermore, by skillfully utilizing ceramic materials, it is possible to prevent the generation of frictional heat and thermal deformation, and it is also possible to enjoy the convenience of extending the stroke simply by extending the guide rail.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing essential parts of one embodiment of a feed device for a machine tool according to the present invention, FIG. 2 is a partial side view taken in the direction of the - arrow in FIG. 1, and FIG. Sectional view according to perspective. 10...Fixed base, 12...Moving object, 22...
... Guide rail, 28 ... Drive roller, 40 ... Pressing roller, 48, 50 ... Leaf spring, 60 ... Flexible joint, M ... Drive motor.

Claims (1)

[Scope of Claims] 1. In a feeding device for a machine tool, a longitudinal guide rail attached to either a fixed base of the machine or a moving body according to the feeding length, and rollingly engaged with both sides of the guide rail. a rolling unit consisting of at least one pair of a drive roller and a pressing roller; a motor that drives the driving roller via a flexible joint; a pressing pressure setting means built into the rolling unit; and a flexible coupling means that is attached to the movable body or the fixed base while being held for fine movement only in a direction perpendicular to the direction, and the movable body is fed and moved according to the forward and reverse rotation of the motor. A feeding device for a machine tool, characterized in that it is configured to 2. The pressing pressure setting means is formed by a spring that clamps and presses the driving roller and pressing roller against the guide rail.
The feed device of the machine tool described in Section. 3. A feeding device for a machine tool according to claim 1 or 2, wherein the flexible coupling means is formed by a plate spring having a plate surface in the feeding direction. 4. A feeding device for a machine tool according to claim 1, wherein the rolling surfaces of the driving roller and the pressing roller are made of a highly wear-resistant ceramic material.