JPS5854948B2 - Machine tool feed device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for moving a moving body such as a machine tool V-mounting table or a spindle head for mounting a cutting tool along the guide surface of a base (bed, column, saddle, etc.). This invention relates to a feeding device for movement.

In order to improve the dimensional accuracy of products manufactured with machine tools, it is necessary to accurately position the workpiece or cutting tool.In order to perform this positioning work efficiently and precisely, the positioning and feeding motion of the moving object is controlled by a servo mechanism. A system using feedback automatic control is well known.

In addition, conventional feed mechanisms include a method in which a feed screw is attached to the base and fixed to the side of the Naratra moving body that engages with the feed screw, and the moving body is moved linearly by rotation of the feed screw, or a direct-acting hydraulic type. Alternatively, a method using a pneumatic cylinder is used.

However, in the case of the feed screw method, the parallelism between the feed screw and the guide surface of the base must be extremely precise, which requires a lot of effort for assembly, and if the parallelism is low, it will be difficult to move. Frictional resistance between the body and the guide surface of the base increases, stress is applied to the guide surface, the positioning accuracy decreases, and the life of the feed device is also shortened.

Even in the case of feeding position using a direct-acting hydraulic or pneumatic cylinder system, the parallelism between the cylinder and the guide surface becomes a problem, requiring laborious assembly work, resulting in problems such as decreased positioning accuracy and shortened service life. There are cases.

Furthermore, in recent years, there has been an increasing demand for machine tools in which the length of the base can be changed by connecting base units in order to be able to process workpieces of various dimensions with a single machine tool. However, in machine tools equipped with conventional feed screw type or cylinder type feed devices, it is not possible to lengthen the stroke of the movable body simply by connecting a base unit due to the structure of the feed device.

The present invention has been made in view of the above points, and does not require strict precision in the mounting position of the feeding device, so does not require time and effort for assembly work, and also eliminates stress applied to the guide surface, resulting in a stable To provide a feed device for a machine tool capable of driving a moving body in a posture with high positioning accuracy and furthermore, easily changing the entering stroke distance of the moving body.

Therefore, in the feeding device according to the present invention, a friction plate for driving the moving body is provided on the base almost parallel to the guide surface of the base, and an equal force is applied to the friction surface of this friction plate from both sides to the moving body. A plurality of drive rollers are provided in pressure contact with each other, and the friction plate is configured to be elastically displaceable in a direction perpendicular to the moving direction of the movable body and to have high rigidity in the moving direction.

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 are cross-sectional views of an embodiment of a feeding device according to the present invention.

FIG. 1 shows a cross section taken along line II in FIGS. 2 and 3. FIG.

Figure 2 is a sectional view taken from ■-■ in Figure 1, and Figure 3 is a cross-sectional view taken from ■-■ in Figure 1.
■It is a sectional view.

Now, in FIG. 1, guide portions 3 for sliding the movable table are formed at both raised ends of a base 1 whose longitudinal direction is perpendicular to the drawing.

The movable table 2 has guide surfaces 3a, 3b,
3c.

A groove 4 for mounting and fixing a workpiece is provided on the upper surface of the movable table 2.

A friction plate 27 for driving the movable table 2 is fixed to the base 1 via a thin elastic part 28 by a friction plate attachment part 26 .

Therefore, this friction plate 27 has a structure that has small lateral rigidity in the left-right direction in the figure and can be elastically displaced as shown by arrow A.

Friction surfaces 27a and 27b are formed on both sides of the friction plate 2γ.

The friction plate 27 is attached to the friction plate mounting portion 26 so that the friction surfaces 27a and 27b are approximately parallel to the moving direction of the moving table 2 that moves along the guide surfaces 3a, 3b, and 3c of the guide portion 3 of the base 1. It is fixed on the base 1.

The first drive roller 15 is in pressure contact with the friction surface 27a, and the second drive roller 16 and the third drive roller 15 are in pressure contact with the friction guide surface 27b on the opposite side.
The drive roller 17 comes into pressure contact (see FIG. 2).

The first, second, and third drive rollers 15, 16, and 17 each have a shaft 15c.

Rigid metal rollers 15 attached to the tips of 16c and 17c
c, 16b, 17b are provided with elastic material layers 15a, 16a, 17a made of a rubber film or the like.

The shaft 15c of the first drive roller 15 is rotatably mounted in a housing 19 via bearings 22, 23, and the housing 19 is fixed to the movable table 2.

The second drive roller 16 is rotatably mounted in a housing 20 via bearings 24 and 25, and the housing 20 is connected to the housing 19 of the first drive roller 15 by a mounting nut 37 via a collar 36.
is rotatably mounted.

A bracket 30 is fixed to the housing 20, one end of a steel belt 31 is fixed to this bracket 30,
The other end of the steel belt 31 is fixed to a bracket 34 fixed to a threaded rod 33 (see FIG. 3).

35 is a guide roller. The threaded rod 33 is fixed to the movable table 2 by a nut 32, and the tension of the steel belt 31 can be adjusted by rotating the nut 32.
It is possible to adjust the pressing force against b.

Similarly, the third drive roller 17 is mounted inside the housing 21, and the housing 21 is rotatably attached to the housing 19.

A bevel gear 10 is fixed to one end of the shaft 15c of the first drive roller 15, and a bevel gear 9 is fixed to the feeding motor 8 side.
meshes with

A gear 13 is fixed with a key on the shirt N5c.

This gear 13 is rotatably attached to the moving table 2 via a bearing 29.

This gear 13 meshes with a gear 14 which is keyed and fixed to the shirt N6c of the second drive roller 16, and a gear 18 which is similarly keyed and fixed to the shirt N7c of the third drive roller 17.
They also mesh together.

The feed motor 8 is connected to a position detector 60 of the moving table 2 via a control circuit 7 .

This position detector 60 is composed of a scale 5 fixed to the movable table 2 side and a reading head 6 fixed to a single base.The scale 5 is made of a material that transmits light and has opaque graduations 56 formed at equal intervals. (See Figure 4).

The reading pad 6 is shaped to sandwich the scale 5 from both sides as shown in FIG. 4, and has a light emitting element 50 on one side.
The other side is provided with a light receiving element 51 facing it.

When the moving table 2 moves and the scale 5 moves along with it in the direction of arrow B, the light from the light emitting element 50 is transmitted or blocked by the scale 56, and the light receiving element 51 emits a detection signal bK according to the number of scales passed through. .

The control circuit 7 includes a counting circuit 55 that counts the number of passing graduations detected by the light receiving element 51, and a comparison circuit 5 that compares the detected number of graduations with the number of graduations corresponding to the distance to be moved according to the command signal a.
2, a DA converter 53, an amplifier 54, etc., and is connected to the feed motor 8.

The operation of the feeding device configured as above will be explained below.

First, the tension of the steel bell I/31 is adjusted by operating the nut 32, and each drive roller 15, 16, 17 is
Pressing force is applied so as to sandwich the friction plate 27 with an appropriate pressure that does not cause a sliding action on 7a and 27b.

At this time, the second drive roller 16 and the third drive roller 17
Each of the shafts 16c and 17c operates on an arc centered on the shirt N5cf of the first drive roller 15, so the distance between the axes of the shaft 15c and both shafts 16c and 17c remains unchanged, and the drive force transmission gears 13, 14.18
The engagement is reliably maintained.

When the feed motor 8 rotates, the rotational force is transmitted to the first drive roller 15 via the bevel gear 9.10f, and the gear 13,
The rotational force is transmitted to the second and third drive rollers 16 and 17 via 14 and 18.

Therefore, for example, if the first drive roller 15 rotates in the direction of arrow C in FIG. 2, each of the drive rollers 16.1γ in FIGS.
, 16a, 17a have a large coefficient of friction, each driving roller 15, 16, 17 reliably comes into frictional contact with the friction surfaces 27a, 27b without slipping, and the movable table moves in the direction of arrow F.

At this time, even if the guide part 3 of the base 1 and the driving friction plate 27 are not completely parallel due to installation error, etc.
Since the driving friction plate 2γ has a thin elastic portion 28, the friction plate 276 swings elastically as shown by arrow A (FIG. 1), and furthermore, the elastic material layer 15a of the hook driving roller 15°16.17
, 16a, and 17a are elastically deformed, so that no unreasonable stress is applied to the guide surface 3a of the base 1 while the movable table 2 is moving.

Also, as shown in FIG. 5, a similar friction plate 2 is attached to the base 1.
It is also possible to easily connect the base units 1a and 1b having the guide parts 3, 3d, 3eg and the friction plates 27, 27c.

2γd can be aligned and connected, the stroke extension of the moving table 2 can be easily achieved.

As described above, in the feeding device according to the present invention, a friction plate is provided for driving the movable body, and the movable body is moved by a drive roller that is in pressure contact with the friction surface of the friction plate. Even if the friction plate elastically displaces in a direction perpendicular to the direction of movement of the friction plate, and the parallelism between the friction plate and the guide surface of the base becomes inconsistent, the drive mechanism of the feeder will be able to compensate for this deviation in parallelism. It is configured to include means for elastically following.

In other words, if there is an imbalance in parallelism between the friction surface of the friction plate and the guide surface of the base, the moving object will try to move based on the guide surface, so it will cross the friction plate via the drive roller. A pressing force in the direction is applied.

At this time, since the thin elastic part of the friction plate is actually installed at a position away from the guide surface, only the friction plate is elastically deformed by a relatively small force in a direction perpendicular to the moving direction of the moving body. It is possible.

Therefore, the friction force between the friction surface of the friction plate and the drive roller hardly changes, and the movable body is never strongly pressed against the guide surface from the lateral direction by the reaction force from the friction plate.

Furthermore, with this configuration, it is possible to easily lengthen the stroke of the moving body by connecting another base unit to the base, and the friction plate for driving the feeder and the guide surface of the base can be easily extended. Since strict accuracy is not required for the parallelism between the feeder and the feeder, the assembly work can be completed in a short time without requiring much effort to attach the feeder, and no undue force is applied to the guide surface.

Furthermore, since the friction plate is driven by being sandwiched between multiple drive rollers from both sides, only the thrust in the direction of movement is transmitted to the moving object, and the guiding surface will not be strained and the moving posture of the moving object will not become unstable. .

Furthermore, although the friction plate has a thin elastic part, it has high rigidity in the longitudinal direction (the moving direction of the moving object), and in conjunction with the position detector and control device, it can position the moving object with high precision. .

The friction plate 27 is rigidly mounted on the base 1 so that it can elastically support the mounting portion of the drive roller and can be displaced in a direction perpendicular to the direction of movement of the movable body while having high rigidity in the direction of movement. Even with a similar structure, the same effects as in the above embodiment can be obtained.

Further, if the stroller of the movable body is short, a friction plate may be provided on the movable body or a drive roller may be provided on the base to perform the feeding motion.

Although the present embodiment shows the case where the friction surface of the friction plate is thicker than the thin elastic portion, the same effect can be obtained even if the friction surface is formed to have the same thickness as the thin elastic portion.

Furthermore, although an optical scale is used as the position detector in the above embodiment, similar effects can be obtained by using other types such as magnetic type, electromagnetic type, or laser interferometer.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of one embodiment of a feeding device according to the present invention, and represents a cross section taken along line II in FIGS. 2 and 3. Figure 2 is a cross-sectional view of Figure 1, and Figure 3 is ll of Figure 1.
It is a 1-1 sectional view. FIG. 4 is a block diagram showing an example of a positioning control circuit of the feeding device shown in FIG. 1, and FIG. 5 is a configuration explanatory diagram showing a method for extending the stroke of the feeding device according to the present invention. 1... Base, 2... Moving table, 3
a, 3b. 3c...Guide surface, 1...Control circuit, 8
...Feed motor, 15, 16.17...
- Drive roller, 15a. 16a, 17a・''elastic material layer, 15c, 16
c. 17c...Shaft, 26...Friction plate mounting portion, 27...Friction plate, 27a, 27b...
...Friction surface, 28... Thin elastic part, 27c
, 27d...Friction plate, 60...Position detector.

Claims (1)

[Scope of Claims] 1. A base, a guide surface provided on the base, a movable body that moves along the guide surface, and a feed drive device that moves the movable body along the guide surface. In a feeding device comprising a position detector for detecting the position of the moving body and a control device receiving a signal from the position detector and controlling the feeding drive device, the base is provided with friction for driving the moving body. A plate is provided substantially parallel to the guide surface, and a plurality of drive rollers are provided on the movable body so as to press the friction surfaces of the friction plate from both sides with equal force, and at least one of the drive rollers is provided. When the friction surface of the friction plate and the guide surface are out of parallel, when the movable body moves with reference to the guide surface, the A pressing force acts on the friction plate, and due to the pressing force, the friction plate can be elastically displaced in a direction perpendicular to the moving direction of the moving body, and has high rigidity in the moving direction of the moving body. The tank bottom has a thin elastic part, and the friction plate is mounted at a position away from the guide surface so that the thin elastic part can be elastically deformed between the friction plate and the guide surface. A machine tool feeding device characterized by: 2. In the feeding device for a machine tool according to claim 1, the surface of the driving roller that presses against the friction plate from both sides is formed of an elastic material layer, and the pressing surface of the driving roller is formed in a direction in which the moving body moves. A machine tool feed device that has a structure that allows it to be elastically displaced in a direction perpendicular to the object.