JPH0396748A - Positioning moving mechanism - Google Patents

Abstract

PURPOSE:To conduct highly precise positioning by providing such a constitution as to change the press contact force of a driving roller to a guide member in proportion to the moving quantity detected by a detecting means. CONSTITUTION:The press contact force generated by a press contact force generating member 44 adapting a piezo element is transmitted to a press contact housing 36, from which it is transmitted to the side surface 20b of a guide bar 20 through a press contact roller 42. As its reaction, a moving table 18 is deflected as shown by the arrow B, and a driving roller 24 is made into press contact with the side surface 20a of the guide bar 20 by a determined press contact force. In the other hand, the moving quantity of the moving table 18 is detected on the basis of the rotating quantity of the detecting shaft 54a of a rotary encoder 54. The roller 24 is rotated by the rotation of a driving motor 28, the driving force is transmitted to the moving table 18 by the frictional engagement between the roller 24 and the side surface 20a of the guide bar 20, and the moving quantity of the moving table 18 is detected by the encoder 54 to conduct highly precise positioning to a target position. In this case, when a large driving force is not required because of the accession to the target position, the press contact force generated by the member 44 is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a positioning and moving mechanism for an object, and particularly to a positioning mechanism that is used in industrial robots, NC machine tools, measuring machines, etc., and which requires a precise feeding function. Regarding the moving mechanism.

[Prior Art] The present applicant previously filed Japanese Patent Application No. 113867/1986,
As a technology that can perform linear motion at high speed and with high precision, we proposed a moving mechanism that can run while supporting a guide bar using the frictional force of rollers.

According to this proposal, there is a movable base that is movable on a guide rail laid on a fixed base, a guide bar that is arranged on the fixed base in parallel with the guide rail, and a guide bar that is in pressure contact with the guide bar, and a movable base that is in pressure contact with the guide bar. a drive roller that is driven by a provided drive source and moves the movable base; and a drive roller provided in relation to the movable base;
The present invention is characterized in that it includes means for detecting the moving position of the movable table, and the movement of the movable table by the drive source is controlled via the detecting means. With this configuration, it is possible to detect the moving position with high precision, and the moving table can be moved at high speed along the guide rail.

[Problems to be Solved by the Invention] However, in the above-mentioned moving mechanism, when moving at high speed or when moving a heavy object, torque is transmitted by the frictional force between the guide bar and the drive roller. Therefore, it is necessary to set a large pressure contact force. Here, the rolling resistance between the drive roller and the guide bar increases in proportion to the increase in the pressing force. If this rolling resistance increases, if the object is slightly deviated from the desired target position, the target position will not be accurately reached unless a large force is generated to overcome the rolling resistance. However, if the restoring force against the shift is too large, it will pass past the target position and return to the opposite direction again, causing so-called vibration.

In addition, in order to perform highly accurate positioning, as the position detection unit becomes more accurate, the restoring force against slight deviations also decreases, and if the restoring force (position feedback gain) is too large, vibrations may occur. I start.

This invention was made in view of the above-mentioned problems, and an object of the invention is to provide a positioning and moving device that can perform highly accurate positioning without vibration.

[Means for Solving the Problems] In order to solve the above-mentioned problems and achieve the purpose, a positioning and moving device according to the first aspect of the present invention includes a fixed base and an arbitrary-shaped extension fixed on the fixed base. a guide member having a protruding surface; a movable base movably supported on the fixed base so as to be movable along the extending surface of the guide member; a drive roller rotatably supported on the movable base; and the drive roller. a driving means for rotationally driving the driving roller, a pressing force generating means for pressing the driving roller against the extending surface of the guide member, and a detecting means for detecting the amount of movement of the moving base, It is characterized in that the pressing force is changed in proportion to the amount of movement detected by the detection means.

Further, a positioning and moving mechanism according to a second aspect of the present invention includes a fixed base, a movable base movably supported by the fixed base,
a guide member fixed to the movable table and having an extending surface of an arbitrary shape; a drive roller rotatably supported on the fixed table while engaging with the extending surface of the guide member; and this drive roller. a driving means for rotationally driving the drive roller; and a pressing force generating means for pressing the driving roller against the extending surface of the guide member;
and a detection means for detecting the amount of movement of the movable table, and is characterized in that the pressing force of the drive roller against the guide member is changed in proportion to the amount of movement detected by the detection means.

Further, in the positioning and moving mechanism according to the present invention, the pressure contact force generating means includes a piezo element.

[Operation] In the positioning and moving device configured as above,
In a moving mechanism that transmits driving force to the moving table using frictional locking, detects the amount of movement of the moving table using a detection means, and positions the moving table with high precision at the target position, as the target position is approached, the moving speed decreases and large When driving force is no longer required, or when a small moving speed is sufficient, reduce the pressure force of the drive roller against the guide member and lower the rolling resistance, thereby reducing the restoring force even if there is a slight deviation. This makes it possible to position the target position with high precision.

[Embodiment] Below, the configuration of an embodiment of the positioning and moving device according to the present invention will be described in detail when applied to a linear moving device with reference to FIGS. i to 4 of the attached drawings. .

As shown in FIGS. 1 and 2, this linear movement device 10
is provided with a fixing base 12 extending along the direction indicated by arrow A (in FIG. 1, the direction perpendicular to the plane of the paper, and in FIG. 2, the left-right direction) on a base (not shown). As shown in FIG. 1, a pair of rail members 14a and 14b are placed on the fixed base 12 in parallel with each other while extending along the one direction A mentioned above. Sliding members 16a and 16b are provided to be slidably fitted to these rail members 14a and 14b from above, respectively, and these sliding members 16a and 16b are fixed to the lower surface of the moving table 18. There is. In this way, the movable table 18 is supported movably along one direction A.

The moving table 18 is formed in the shape of a rectangular parallelepiped with a hollow interior, and both front and rear end surfaces along one direction A are open.

As shown in FIG. 2, a guide bar 20 formed to extend along one direction A passes through a substantially central portion of the movable table 18. Here, this guide bar 20 has both ends supported by support stands 2 2 a, 2 2
It is fixed to the upper surface of the fixed base 12 via b. Both side surfaces 20a extending along one direction A of this guide bar 20
20b is set to be exactly parallel to the above-mentioned rail members 14a, 14b.

On the other hand, the movable table 20 includes a drive roller 24 having an outer peripheral surface that rolls into contact with one side surface 20a of the guide bar 20.
It is rotatably supported around a vertical axis via a pair of upper and lower bearings 26a and 26b. Here, a drive motor 28 for rotationally driving the drive roller 24 is mounted on the movable table 18 via a mounting stay 30 with its drive shaft 28a extending downward. is fixed. The lower end of the drive shaft 28a and the upper end of the drive roller 24 are connected to each other via a coupling 32.

Here, in response to activation of the drive motor 28, the drive roller 2
4 will be rotationally driven, but if the drive roller 24 and guide bar 20 are not frictionally engaged with a predetermined pressure contact force, the movable table 18 will not move in accordance with the rotation of the drive roller 24. become. Therefore, as shown in Figure 1,
Inside the movable table 18, the other side 2 of the guide bar 20
On the Ob side, there is a pressure contact mechanism 34 for pressing the guide bar 20 and the drive roller 24 against each other to bring them into frictional engagement.
is installed.

This pressure contact mechanism 34 includes a pressure contact housing 36 that is movable within the movable table 18 along the other direction B orthogonal to the above-described one direction A. This press-contact housing 36 has a hollow interior, and a surface facing the other side surface 20b of the guide bar 20 is completely open. A support shaft 38 extending vertically is fixed within the press-contact housing 36. Further, a pressure roller 42 is rotatably supported on this support shaft 38 via a bearing 40 . This pressure roller 42 is set to roll (press) into contact with the other side surface 20b of the guide bar 20.

On the other hand, on the opposite side of the pressure housing 36 to the side where the guide bar 20 is provided, a pressure force generating member 44 that generates a pressure force for pressing the pressure housing 36 toward the guide bar 20 is disposed. It is set up. In this embodiment, the pressure contact force generating member 44 employs a piezo element so that the pressure contact force can be changed to an arbitrary value at high speed.

Since the pressure welding mechanism 34 is configured in this manner, the pressure welding force generated by the pressure welding force generating member 44 is first transmitted to the pressure welding housing 36, and from there, the pressure welding force generated by the pressure welding force generating member 44 is transmitted to the support shaft 38, the bearing 4
0, it is transmitted to the other side surface 20b of the guide bar 20 via the pressure roller 42. In this way,
As a reaction force of the pressure contact force between the pressure roller 42 and the other side surface 20b of the guide bar 20, the movable table 18 is biased as shown by arrow B, and as a result, the drive roller 24 attached to the movable table 18 is biased. is brought into pressure contact with one side surface 20a of the guide bar 20 with a predetermined pressure contact force.

In this way, a frictional engagement between the welding roller 24 and the guide bar 20 is achieved in this embodiment.

It should be noted that if the pressing force generated by the above-mentioned pressing force generating member 44 becomes strong, the pressing force between the drive roller 24 and the guide bar 20 also increases, and if the pressing force generated becomes weak, the pressing force between them also increases. It becomes weaker.

Further, in this embodiment, the fixed base 1 of the movable base 18
A movement amount detection mechanism 46 is provided to detect the movement position (movement amount) with respect to 2. As shown in FIG. 1, this movement amount detection mechanism 46
A rack member 48 is attached to the fixed base 12 via a stay 50 in a state where it extends along one direction A adjacent to the rack member 48 . On the other hand, a rotary encoder 54 is attached via a stay 52 to the side surface of the movable table l8 on the side where the rack member 48 is disposed.

The rotary encoder 54 includes a detection shaft 54a projecting downward, and the rotary encoder 54 is configured to detect the amount of movement of the moving table l8 based on the amount of rotation of the detection shaft 54a. There is. Therefore, a pinion gear 56 that meshes with the rack member 48 described above is coaxially attached to the lower end of the detection shaft 54a. Since the movement amount detection mechanism 46 is configured in this manner, the movement amount of the movable table 18 is accurately detected based on the detection result from the rotary encoder 54.

Since the linear movement device 10 is configured as described above,
When it moves between two points indicated by symbols A and D, as shown in Figure 3 (A), in the relationship between moving speed and moving time, the horizontal axis represents the moving time and the vertical axis represents the moving speed. Then, the amount of movement of the linear movement device 10 becomes the area shown by hatching.

On the other hand, in FIG. 3(A), from point A to point B is defined as an acceleration region, from point B to point C as a constant velocity region, and from point C to point D as a deceleration region. Here, FIG. 3(B) shows the required torque for movement in the movement mode shown in FIG. 3(A). As is clear from Fig. 3 (B), when final positioning is to be performed with high precision at point D, the final movement speed must be sufficiently reduced and the required torque at that point must be large. It's something you don't do.

However, as shown in FIG. 4, the pressure contact force and rolling resistance are almost proportional to each other, so if the drive roller 24 is pressed against the guide bar 20 with a large pressure contact force near point D, it will not roll. The resistance increases and a large amount of restoring force is required. As a result, if the contact force is too large, vibration will occur. Therefore, as shown in Fig. 3 (C), by adjusting the pressure contact force so that it is almost proportional to the absolute value of the required torque, highly accurate positioning can be performed at point D, and vibrations can be reduced. will be achieved.

Also, for example, part a and b in the 31st ffl(A)
If pressure contact force is constantly applied to transmit the necessary torque, approximately 70% of the total load resistance will be rolling resistance, and the remaining 30% will be resistance from other parts such as bearings. This means that positioning accuracy of only about .1 mm can be obtained.

However, in this embodiment, near point D,
By lowering the pressing force, positioning of about 0.01 mm becomes possible. In addition, since the entire area is pressed with the necessary contact force, the movement time is not extended and positioning movement can be performed with high precision. Moreover, the amount of friction between the drive roller 24 and the guide bar 20 is reduced, and the durability can also be improved without pressing more forcefully than necessary.

It goes without saying that this invention is not limited to the configuration of the embodiments described above, and can be modified in various ways without departing from the gist of the invention.

For example, in the above-mentioned embodiment, it was explained that a piezo element that can change the pressure contact force quickly and with high precision is used as the pressure contact force generating member. There is no limitation, and there is no problem in using a fluid cylinder or the like.

Further, in the above-mentioned embodiment, the case where the present invention is applied to a linear movement device has been described, but the present invention is not limited to such an application, and for example,
As shown in FIG. 5 as another embodiment of the present invention, it can be applied to a rotational movement device.

The structure of another embodiment in which the present invention is applied to a rotational movement device will be described below with reference to FIG. 5. In the following description, the same parts as in the above-mentioned embodiment are given the same reference numerals, and the description thereof will be omitted.

That is, in this other embodiment, as shown in FIG. 5, a cylindrical support member 60 is fixed on the fixing table 12. And, on the outer periphery of the upper part of this support member 60,
A substantially cylindrical moving table 62 with an open bottom surface is fitted and rotatably supported via a bearing 64 . Here, this movable table 62 includes a rotary plate 62 constituting a top plate portion.
a, and a ring-shaped guide ring 62b fixed to the outer periphery of the lower surface of the rotary plate 62a. In this way, in other embodiments, the movable table 62 is rotatably supported above the fixed table 12.

On the fixed base l2 on the side of this movable base 62, there is a movable base 62
A mounting housing 66, which has an open surface facing the mounting housing 66 and a hollow interior, is fixed thereto.

A press-contact housing 68 whose surface facing the movable base 62 is open and whose interior is hollow is mounted within the mounting housing 66 so as to be movable forward and backward relative to the movable base 62 . Inside this press-contact housing 68, the drive roller 24 is rotatably supported around a vertical axis by bearings 26a, 26b at the top and bottom.

Here, the drive roller 24 is set so as to be in rolling contact (pressure contact) with the outer peripheral surface of the guide ring 62b which functions as a guide bar in the above-described embodiment.

Note that the drive motor 2 for rotationally driving the drive roller 24
8 is located above the drive roller 24 and is fixed to the upper part of the pressure contact housing 68, and the drive shaft 2 of this
8a is connected to the drive roller 24 via a coupling 32.

In this other embodiment, the guide ring 62
In order to press the drive roller 24 and the driving roller 24 into frictional engagement with each other, the press housing 68 and the mounting housing 66 are provided between the press housing 68 and the mounting housing 66 by urging the press housing 68 toward the movable table 62 so that both A pressing force generating member 44 is interposed to generate a pressing force between the two. This pressure contact force generating member 44
is composed of a piezo element, similar to the above-mentioned embodiment.

Further, in this other embodiment, a rotation amount detection mechanism 70 is provided to detect the rotation position (rotation amount) of the movable table 62 with respect to the fixed table 12. The rotation amount detection mechanism 70 includes a detected portion 72 protruding downward from the center of the lower surface of the rotary plate 62a, a rotary encoder 54 fixed on the fixed base 2 via a stay 52, and the rotary encoder 54 It is composed of a coupling 74 that connects the detection shaft 54a and the detected portion 72.

In this way, the rotary encoder 54
The amount of rotation of the movable table 62 is detected based on the amount of rotation of the detection shaft 54a, which rotates based on the rotation of the detection shaft 2a. Since the rotation amount detection mechanism 70 is configured in this manner, the rotation amount of the movable table 62 is accurately detected based on the detection result from the rotary encoder 54.

By configuring other embodiments in this way, the positioning and moving device according to the present invention can be favorably applied to a rotational moving device.

Furthermore, in the above-described embodiment, the movable table 18 equipped with the drive roller 24 was explained to move along the guide bar 20 fixed on the fixed table 12, but the present invention is not limited to such a configuration. Without being limited to, the drive roller 2
There is no problem even if the portion supporting the guide bar 4 is fixed on the fixed base 12 and the guide bar 20 is configured to move along one direction on the fixed base 12.

Similarly, in the other embodiments described above, the guide ring 62b is fixed on the fixed base 12, and the mounting housing 66 supporting the drive roller 24 rotates on the fixed base 12 along the outer periphery of the guide ring 62b. There is no problem in configuring it so that it can be moved.

[Effects of the Invention] As detailed above, the positioning and moving device according to the first aspect of the present invention includes a fixed base, a guide member fixed on the fixed base and having an optionally shaped extending surface, and the fixed base. Above,
a movable base movably supported along the extending surface of the guide member; a drive roller rotatably supported on the movable base; a drive means for rotationally driving the drive roller; and a guide for the drive roller. It comprises a pressing force generating means for pressing the extending surface of the member, and a detecting means for detecting the amount of movement of the moving table, and the pressing force of the drive roller against the guide member is determined by the amount of movement detected by the detecting means. It is characterized by changing in proportion to.

Further, a positioning and moving mechanism according to a second aspect of the present invention includes a fixed base, a movable base movably supported by the fixed base,
a guide member fixed to the movable table and having an extending surface of an arbitrary shape; a drive roller rotatably supported on the fixed table while engaging with the extending surface of the guide member; and this drive roller. a driving means for rotationally driving the drive roller; and a pressing force generating means for pressing the driving roller against the extending surface of the guide member;
and a detection means for detecting the amount of movement of the movable table, and is characterized in that the pressing force of the drive roller against the guide member is changed in proportion to the amount of movement detected by the detection means.

Further, in the positioning and moving mechanism according to the present invention, the pressure contact force generating means includes a piezo element.

Therefore, according to the present invention, a positioning and moving device that can perform highly accurate positioning without vibration is provided.

[Brief explanation of drawings]

Fig. 1 is a front view showing the configuration of an embodiment of the positioning movement device according to the present invention applied to a linear movement device; Fig. 2 is a side view of the linear movement device shown in Fig. 1; Fig. 3 is a diagram showing the change state of speed, required torque, and pressure contact force as they change with the elapsed travel time; Figure 4 is a diagram showing the relationship between pressure contact force and rolling resistance; and Figure 5 is a diagram showing the relationship between pressure contact force and rolling resistance. FIG. 2 is a front view showing the configuration of another embodiment in which the positioning and moving mechanism according to the present invention is applied to a rotational moving mechanism. In the figure, 10... linear movement device, 12... fixed base, 1
4a; 14b - rail member, 16a, 16b - sliding member, 18... moving table, 20... guide par 22a
; 22b... Support stand, 24... Drive roller, 26a
26b... Bearing, 28... Drive motor, 28a... Drive shaft, 30... Mounting stay, 32...
... Coupling, 34 ... Pressure contact mechanism, 36 ... Pressure contact housing, 38 ... Support shaft, 40 ... Bearing, 42 ... Pressure contact roller, 44 ... Pressure contact force generating member,
46... Movement amount detection mechanism, 48... Rack member, 5
0... Stay, 52... Stay, 54... Rotary encoder, 54a... Detection shaft, 56... Pinion gear, 60... Support member, 62... Moving table, 62
a...Rotating plate, 62b...Guide ring, 64...
・Bearing, 66...Mounting housing, 68...
Pressure contact housing, 70...Rotation amount detection mechanism, 72...
- Detected part, 74... is a coupling. (A) (Japanese) (C) Figure 3 Figure 4

Claims (3)

[Claims] (1) a fixed base; a guide member fixed on the fixed base and having an optionally shaped extending surface; and a movable base supported on the fixed base so as to be movable along the extended surface of the guide member; , a drive roller rotatably supported by the moving table; a driving means for rotationally driving the driving roller; a pressure generating means for pressing the driving roller against the extending surface of the guide member; and movement of the moving table. 1. A positioning and moving mechanism, comprising: a detection means for detecting the amount of movement, and changing the pressure force of the drive roller against the guide member in proportion to the amount of movement detected by the detection means. (2) a fixed base; a movable base movably supported by the fixed base; a guide member fixed to the movable base and having an extending surface of an arbitrary shape; and an extension of the guide member on the fixed base. a drive roller that is rotatably supported while engaging with the exit surface; a drive means that rotationally drives the drive roller; a pressure generating means that presses the drive roller against the extension surface of the guide member; and the movable table. A positioning and moving mechanism, comprising: a detection means for detecting the amount of movement of the drive roller, and changing the pressing force of the drive roller against the guide member in proportion to the amount of movement detected by the detection means. (3) The positioning and moving mechanism according to claim 1 or 2, wherein the pressure contact force generating means includes a piezo element.