JPH07100310B2 - Moving mechanism - Google Patents

Description

The present invention relates to a moving mechanism, and more specifically, an industrial robot or
The present invention relates to a moving mechanism used in NC machine tools and the like, which requires precise linear movement.

[Conventional technology]

The present applicant has previously proposed a moving mechanism capable of traveling with the guide bar held by the frictional force of the rollers as a means capable of performing linear movement at high speed and with high accuracy. (Actual development
62-113867 to 113870) According to this proposal, a movable base that is movable on a guide rail laid on the fixed base, a guide bar arranged on the fixed base in parallel with the guide rail, and a guide bar. And a drive roller that is pressed against and is driven by a drive source provided on the moving table to move the moving table, and is provided in association with the moving table.
And a means for detecting the moving position of the moving table, wherein the movement of the moving table by the drive source is controlled via the means for detecting the moving position of the moving table.
With this configuration, it is possible to detect the moving position with high accuracy, and further, the moving table can be moved at high speed along the guide rail.

[Problems to be Solved by the Invention]

However, in the moving mechanism as described above, it is generally difficult to accurately set the relative positions of the guide bar and the driving roller and the pressure contact roller on the moving table arranged so as to narrow the guide bar. Therefore, there is a case where only the upper part of the guide bar comes into contact with the drive roller, for example. However, when the continuous motion is performed in such a state, there is a problem that the service life of the guide bar, the driving roller and the pressure contact roller becomes extremely short.

An object of the present invention is to pay attention to the above-mentioned conventional problem, and in order to solve the problem, a guide bar is always held in a state in which a guide bar is closely held between a drive roller and a pressure contact roller, and a movable table is run. It is to provide a moving mechanism capable of extending the life of the entire apparatus.

[Means for Solving the Problems]

In order to achieve such an object, the present invention provides a movable base which is movable on a guide rail laid on a fixed base, and both ends of which are fixed to the fixed base and arranged in a space in parallel with the guide rail. A guide bar with a rectangular cross-section that has been installed,
A pressure roller is in pressure contact with a side surface of the guide bar, is driven by a drive source provided in the movable table, and is in contact with a side surface of the guide bar opposite to the side surface of the guide bar in which the drive roller is in pressure contact. And holding the guide bar between it and the drive roller, and having a pressure contact roller for generating a pressure contact force to the guide bar at the drive roller, the drive roller and the drive roller near both ends of the guide bar. It is characterized in that a concave portion is provided on both side surfaces against which the pressure roller is in pressure contact, and the guide bar is allowed to bend in the horizontal direction and twisted around the beam neutral axis by reducing the cross-section by both of the concave portions. is there.

[Operation] According to the present invention, the guide bar sandwiched between the drive roller and the pressure contact roller has a rectangular cross-sectional shape, and both the drive roller and the pressure contact roller are in pressure contact in the vicinity of both ends of the guide bar. Since the guide bar itself is bent according to the holding force transmitted from both rollers due to the reduction of the cross section by providing the concave portion on the side surface, it is possible to bring the drive roller and the pressure contact roller into close contact with the guide bar. It has become possible to prevent contact and extend the operating life of the device.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to an orthogonal robot.
Here, 1 is a fixed base, 2 is a movable base capable of traveling on the fixed base 1, and 3 is a robot arm attached to the movable base 2. In this example, although not shown, a traveling member that is movable along the robot arm 3 is provided, and a robot hand that is vertically movable is provided on the traveling member.

Reference numeral 4 denotes a guide rail arranged on the moving table 2,
As shown in the figure, two guide rails 4 are arranged in parallel. Reference numeral 5 denotes a guide bar. The guide bar 5 is arranged in parallel with the guide rail 4 and in a hollow position on the fixed base 1. Both ends of the guide bar 5 are fixed by the bar fixing members 6 and the moving base 2 described above is used. Upper component plate 2A and lower component plate
It will be installed so as to pass through the space between 2B and.

Reference numeral 7 denotes a servomotor mounted on the moving base 2 via a support base 8. A rotary shaft 7A of the motor 7 is connected to a drive roller shaft 10A via a coupling 9 and the drive roller shaft 1
A drive roller 10 that comes into contact with the side surface of the second guide bar 5 is attached to the tip of 0A. Reference numeral 11 is a bearing that axially supports the drive roller shaft 10A as shown in FIG.

In this example, as shown in FIG. 3, with respect to the drive roller 10 which keeps contact with the guide bar 5 in this manner, a pressure contact roller member 12 is arranged on the side surface on the opposite side of the guide bar 5, and the pressure contact roller member 12 is disposed. The spring 13A of the spring housing member 13 as shown in FIG.
By this, it is biased toward the guide bar 5, so that the drive roller 10 is brought into close contact with the guide bar 5. That is, since the guide bar 5 is sandwiched between the pair of press contact rollers 14 provided on the press contact roller member 12 and the drive roller 10, the motor 7 is driven and rotated to move the entire movable table 2 to the guide bar 5. Can be moved along.

However, here, in this example, the guide bar 5 having a rectangular cross section is
As shown in FIG. 1, a concave portion is formed in the vicinity of the support portions at both ends thereof so that both side surfaces thereof are smoothly cut out, and the narrow beam portion 50 is formed by sandwiching the width direction thereof. Bends in the left-right direction via the narrow beam portion 50 and twists around the beam neutral axis indicated by arrow M.

By constructing the guide bar 5 in this manner, the relative positions of the drive roller 10 and the pressure contact roller 14 with respect to the guide bar 5 are slightly bad, and even if one-sided contact tends to occur, the guide bar 5 has a narrow beam portion. Since it bends via 50 and is displaced between the drive roller 10 and the pressure contact roller 14 in such a manner that it can be easily pinched, it is possible to solve the problems of the prior art.

Further, in FIG. 1, reference numeral 21 is a rotary encoder mounted on the moving table 2, and 22 is a pinion gear device (hereinafter simply referred to as a pinion gear) mounted via a coupling (not shown) with the encoder 21. The pinion gear 22 is composed of two upper and lower stages, as will be described later. When the pinion gears 22 mesh with the rack gear 23 provided on the fixed base 1, the motor 7 moves the moving base 2 to the first position. When it is moved along the first guide rail 4, its movement position can be detected via the encoder 21, and therefore, the movement of the moving table 2 can be accurately controlled via the encoder 21.

Next, referring to FIG. 4, the meshing state of the pinion gear 22 and the rack gear 23 and the configuration thereof will be described in detail.
In FIG. 4, 24 is a coupling that connects the rotary shaft 21A of the encoder 21 and the pinion gear shaft 25, and 26 is a bearing that supports the pinion gear shaft 25. Here, the pinion gear 22 is composed of an upper pinion gear 22A fixed to the pinion gear shaft 25, and a lower pinion gear 22B rotatably loosely fitted to the pinion gear shaft 25,
A lubricating member 31 is fitted to the lower pinion gear 22B so as to be slidably rotatable with respect to the shaft 25. Further, as shown in FIG. 5A, play holes 27 are provided in the upper pinion gear 22A, and pins 28 erected from the lower pinion gear 22B are fitted in these play holes 27 so that they can be finely moved.
The spring force of the spring 30 hooked between the fixing pin 29 and the fixing pin 29 maintains the biasing force for rotating the lower pinion gear 22B in the arrow direction.

Therefore, if the moving base 2 is temporarily moved to an arbitrary position and stopped there, the upper and lower pinion gears of the pinion gear 22 are kept in a rotational direction opposite to each other by the biasing force of the spring 30. By leaning, it meshes with the rack gear 23 in the state shown in FIG. 5B, and there is no risk of backlash occurring between them.

In the moving mechanism configured as described above, when the robot arm 3 is moved via the moving base 2, the pressure roller is pressed.
The reaction force F received by 14 is determined by the conditions of the acceleration α of the robot arm 3 and its mass m, while the pressure contact roller 14 withstands the reaction force F and keeps the guide bar 5 from slipping. Have to be drunk. That is, the friction coefficient between the guide bar 5 and the pressure roller 14 is μ
If It is necessary to set the pressure contact force P that satisfies the condition of the expression (1), and therefore, the spring force of the spring 13A is set under the conditions as described above.

According to the present example, the drive bar 10 is moved by being driven by the motor 7 while the guide bar 5 is held between the drive roller 10 and the press contact roller 14 with the above-described press contact force P. The robot arm 3 can be freely moved to a desired position via the base 2, and the positioning by the movement is directly meshed with the encoder 21 and the backlash-free pinion gear device 22 and the rack gear 23. It is possible to move the robot arm 3 while maintaining highly accurate positioning, and in this case, the guide bar 5 is moved between the drive roller 10 and the pressure contact roller 14 by the pressure contact force as described above. On the other hand, since the guide bar 5 is configured to bend to the left and right through the narrow beam portion 50 while being held by There is no such thing as. The present applicant prototyped an experimental device and was able to implement accurate position regulation at a maximum moving speed of 1.5 m / sec.

Further, in this example, the movable table 2 which is the main body of the movable body is moved across the two first guide rails 4, and the motor 7 which controls the movement is mounted on the movable table 2. As long as there is a sufficient gripping force due to the friction between the drive roller 10 driven by the motor 7 and the pressure contact roller 14 in order to move the guide bar 5 while sandwiching it, even if friction occurs The device can be operated without any trouble and with high accuracy. Furthermore, even if a slip occurs between the guide bar 5 and the roller, the pinion gear 22 and the rack gear 22 have no backlash.
The movable table 2 can be regulated to an accurate moving position by meshing with 23. Further, it is needless to say that the strength of the above-mentioned pressure contact force P can be freely changed by adjusting the spring 13A, and the moving mechanism itself can be easily assembled and adjusted, and sufficient durability can be provided.

In the embodiment described above, the narrow beam portion 50 is formed by providing notches from the left and right sides, but the shape of the narrow beam portion formed at both ends of the guide bar is not limited to this. It goes without saying that the cross section may be of a reduced shape that causes the guide bar 5 to bend in conformity with the pressure contact force received from the roller and to bring it into close contact with the drive roller 10.

〔The invention's effect〕

As described above, according to the present invention, a movable base that is movable on a guide rail laid on a fixed base and both ends of the movable base are fixed to the fixed base, and a space is formed in parallel with the guide rail. An arranged guide bar having a rectangular cross-sectional shape, a drive roller that is pressed against a side surface of the guide bar and is driven by a drive source provided on the moving table to move the moving table, and the guide bar of the guide bar. A pressure roller that presses the side surface opposite to the side surface on which the drive roller presses, and holds the guide bar between the drive roller and the drive roller to generate a pressure contact force to the guide roller. A concave portion is provided on both side surfaces of the guide bar near both ends of the guide bar where the drive roller and the pressure contact roller are in pressure contact with each other. Since twisting around the shaft is allowed, the guide bar is easier to use as a drive roller and a pressure contact roller, even if the relative mounting positions of the guide bar and the drive roller and pressure contact roller are slightly displaced. The contact can be maintained, the wear of the device can be extended to prevent the wear thereof, and the entire assembling work including the attachment of the guide bar can be facilitated.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of the structure of the moving mechanism of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a perspective view schematically showing the drive system of FIG. 1 taken out. FIGS. 4 and 5 are sectional views of the moving position detecting device according to the moving mechanism of the present invention, and FIGS. 5A and 5B are explanatory views of the lashless pinion rack mechanism of the moving position detecting device. 1 ... Fixed base, 2 ... Mobile base, 3 ... Robot arm, 4 ... First guide rail, 5 ... (Second) guide bar, 7 ... Servo motor, 7A ... Drive shaft, 8 ... … Support base, 10 …… Drive roller, 12 …… Pressure contact roller member, 13 …… Spring housing member, 13A …… Spring, 14 …… Pressure contact roller, 21 …… Encoder, 22,22A, 22B …… Pinion gear, 23 …… Rack gear, 27 …… Play hole, 30 …… Spring, 31 …… Lubrication member, 50 …… Narrow beam part.

Claims (1)

[Claims] 1. A movable base which is movable on a guide rail laid on a fixed base, and a rectangular cross-sectional shape in which both ends are fixed to the fixed base and which is arranged in a space parallel to the guide rail. A guide bar, a drive roller that is in pressure contact with a side surface of the guide bar and is driven by a drive source provided in the movable table to move the movable table, and a side surface of the guide bar in which the drive roller is in pressure contact. A pressure contact roller that presses against the side surface on the opposite side and holds the guide bar between the drive roller and the drive roller to generate a pressure contact force to the guide bar; A concave portion is provided on both side surfaces of the drive roller and the pressure contact roller which are in pressure contact with each other, and the cross-sectional reduction by the both concave portions allows the guide bar to bend in the horizontal direction and twist around the beam neutral axis. A moving mechanism characterized by doing so.