JPH052309Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a moving mechanism, and more specifically, to a moving mechanism that is used in industrial robots, NC machine tools, etc. and requires precise linear motion.

[Conventional technology]

This application has previously proposed a moving mechanism that can run while holding a guide bar using the frictional force of rollers as a means of performing linear motion at high speed and with high precision. (Refer to Japanese Patent Application Nos. 113868 to 113870) According to these proposals, there is a movable platform that is movable on a guide rail laid on a fixed platform, and a movable platform that is arranged parallel to the guide rail on the fixed platform. A guide bar, a drive roller that is in pressure contact with the guide bar and is driven by a drive source provided on the moving base to move the moving base, and a drive roller that is provided in relation to the above-mentioned moving base and detects the moving position of the moving base. The present invention is characterized in that the movement of the movable base by the drive source is controlled via the means for detecting the moving position of the movable base.
It is possible to detect the moving position with high precision,
Furthermore, the movable table can be moved at high speed along the guide rail.

[The problem that the idea attempts to solve]

However, in the above-mentioned moving mechanism,
Generally, it is difficult to accurately set the relative position of the guide bar and the drive roller and pressure roller on the movable table, which are arranged to sandwich the guide bar, and uneven contact often occurs. For example, a situation may arise in which only the upper part of the guide bar contacts the drive roller. However, when continuous movement is performed under such conditions, there is a problem in that the life of the guide bar, drive roller, and pressure roller is significantly shortened.

In addition, in recent years assembly robots have been required to improve their movement/stopping speed and position accuracy, and cost performance through unmanned high-speed operation is desired, but in the case of the above-mentioned movement mechanism, Due to the reasons described below, the fourth
As shown in the figure, the roller shaft 10A of the drive roller 10 is precisely aligned in the vertical direction α ₁ with respect to the moving direction of the moving table 2.
However, there remained an issue that remained to be resolved, namely that it could not be maintained at a constant angle and was tilted.

That is, in FIG. 4, 1 is a fixed base,
4 is a guide rail mounted on the fixed base 1 (only one of the two is shown in this example), and 5 is a guide rail mounted on the fixed base 1 via a fixing member 6 in parallel with the guide rail 4. fixed guide bar,
Reference numeral 2 denotes a movable base slidably held on a guide rail 4, and 7 a servo motor mounted on the movable base 2 via a support base 8 to drive a drive roller 10.

In the moving mechanism configured in this way, a guide bar 5 is provided between the drive roller 10 and the pressure roller (not shown).
By driving and rotating the servo motor while the rollers 10 are being held between the rollers 10 and the guide bar 5, the movable table 2 moves at high speed in the direction of the arrow. A force acts to displace the guide bar 5 in the direction a or b.

Note that the above-mentioned inclination is mainly caused by the roller 10.
This is due to some play in the assembly structure, such as the fact that the heavy servo motor 7 is mounted on the top and the roller shaft 10A is supported by the movable table 2 via a bearing. As a result, the above-described action causes slippage between the roller 10 and the guide bar 5, which further causes an excessive load to be applied to the servo motor 7.

By the way, assuming that the inclination angle θ is 30 minutes, the diameter of the roller 10 is 22 mm, and the moving distance is 500 mm, the guide bar 5
Assuming that it can be moved up and down freely according to its movement, the amount of vertical displacement is as much as 4.36 mm. Therefore, in the case of a device in which displacement is detected by the roller 10, this appears as an error in the moving position.

The purpose of this invention is to focus on the above-mentioned conventional problems, and in order to solve them, it is possible to move the drive roller without slipping between the roller and the guide bar even if the drive roller has some inclination. The objective is to provide a moving mechanism that can

[Means to solve the problem]

In order to achieve this purpose, the present invention includes a movable base that is movable on a guide rail laid on a fixed base, and a movable base that has both ends fixed to the fixed base and is arranged in a space parallel to the guide rail. A guide bar, a drive roller that is in pressure contact with the side surface of the guide bar and that is driven by a drive source provided on the movable base to move the movable base, and the guide bar is held between the drive roller and the drive roller. In a moving mechanism having a pressing roller that generates a pressing force from the guide bar to the guide bar, a reduced cross-section portion is provided near both ends of the guide bar to reduce the cross section of the guide bar symmetrically in the vertical and horizontal directions. It is characterized in that the reduced cross-section portion allows the guide bar to deflect in the horizontal and vertical directions and torsion around its neutral axis.

[Effect]

According to the present invention, the cross section of the guide bar is symmetrically reduced in the vertical and horizontal directions near both ends thereof, and a reduced cross section is provided, so that the drive roller axis is tilted with respect to the vertical direction. Even if something like this happens, the guide bar flexes in line with the drive roller and pressure roller, so there will be no slippage between the guide bar and the drive roller, allowing the mechanism to operate smoothly. be able to.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail and specifically based on 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 that can run and move on the fixed base 1, and 3 is a robot arm attached to the movable base 2. Although not shown in this example, a running member is provided on the robot arm 3 and is movable along the robot arm 3, and a robot hand that can move up and down in the vertical direction is further provided on the running member.

Reference numeral 4 indicates a guide rail disposed on the movable table 2, and as shown in FIG. 2, two guide rails 4 are arranged in parallel. Further, in FIG. 1, reference numeral 5 denotes a guide bar, and the guide bar 5 is arranged parallel to the guide rail 4 and in a hollow position on the fixed base 1, and both ends thereof are connected to the bar fixing member 6 by fixing pins 5.
0, and is guided so as to pass through the space between the upper component plate 2A and the lower component plate 2B of the above-mentioned moving platform 2.

Reference numeral 7 denotes a servo motor mounted on the movable table 2 via a support stand 8, and the rotating shaft 7A of the motor 7 is connected to the drive roller shaft 10A via a coupling ring 9. A drive roller 10 is attached which contacts the side surface of the second guide bar 5 mentioned above. Note that 11 is a bearing that supports the drive roller shaft 10A as shown in FIG.

In this example, with respect to the drive roller 10 that maintains contact with the guide bar 5, a pressure roller member 12 is attached to the opposite side of the guide bar 5, as shown in FIG.
The pressure roller member 12 is biased toward the guide bar 5 by the spring 13A of the spring housing member 13 as shown in FIG. 2, thereby bringing the drive roller 10 into close contact with the guide bar 5. . That is, since the guide bar 5 is held between the pair of pressure rollers 14 provided on the pressure roller member 12 and the drive roller 10, the drive rotation of the motor 7 moves the entire movable table 2 to the guide bar. 5
can be moved along.

However, in this example, the guide bar 5 having a rectangular cross section is inserted into the first
As shown in the figure, the narrow beam portion 60 is provided by symmetrically and smoothly gouging out from the four sides of the top, bottom, left and right, and thereby narrowing the width direction. Deflection in the vertical direction indicated by arrow L, and deflection in the horizontal direction indicated by arrow N,
and twisting around the beam neutral axis indicated by arrow M is made easy to occur.

By configuring the guide bar 5 in this way, even if the relative mounting positions of the drive roller 10 and the pressure roller 14 with respect to the guide bar 5 are somewhat poor and there is a tendency for uneven contact to occur, the guide bar 5 is better positioned at its narrow beam portion. Deflecting through 60, drive roller 1
0 and the pressure roller 14 so that it is easily held between the roller 14 and the pressure roller 14.

Furthermore, even if the drive roller 10 and its roller shaft 10A are mounted with an angular error θ as shown in FIG. 4, the guide bar 5 is fixed to the fixing member 6 via the fixing pin 50. ,
Moreover, by forming the narrow beam parts 60 near the support parts at both ends, it can be easily moved slightly in the vertical and horizontal directions, and since it follows the drive roller 10, there is no slippage between them, and the life of the device can be extended. can contribute.

Furthermore, in FIG. 1, 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) that is mounted to the encoder 21 via a coupling (not shown). However, although not shown, the lever pinion gear 22 is constructed of two stages (upper and lower) biased in opposite directions by springs to prevent backlash, and these pinion gears 22 are connected to a rack gear 23 provided on the fixed base 1. By meshing, when the movable table 2 is moved along the first guide rail 4 by the motor 7, the movement position can be detected via the encoder 21. Mobile platform 2
movement can be precisely controlled.

Now, if the moving table 2 is temporarily moved to an arbitrary position and stopped there, the upper and lower pinion gears of the pinion gear 22 are urged in opposite rotational directions by the urging force of a spring (not shown). Therefore, there is no risk of backlash occurring between the gear and the rack gear 23.

In the moving mechanism configured in this way, when the robot arm 3 is moved via the moving table 2, the reaction force F that the pressure roller 14 receives depends on the acceleration α of the robot arm 3 and its mass m. On the other hand, the pressure roller 14 must be able to withstand the reaction force F and must be maintained in a state where no slipping occurs between it and the guide bar 5. That is,
When the coefficient of friction between the guide bar 5 and the pressure roller 14 is μ, P<F/μ=mα/μ... (1) Set the pressure force P that satisfies the condition of equation (1). Therefore, the spring force of the spring 13A is set under the above-mentioned conditions.

According to this example, the driving roller 10 is moved by the motor 7 while the guide bar 5 is held between the driving roller 10 and the pressing roller 14 with the pressing force P as described above. By driving, the robot arm 3 can be freely moved to a desired position via the moving table 2.
Moreover, the positioning by the movement is performed by the encoder 21.
This is achieved by the meshing state between the pinion gear device 22 and the rack gear 23, which are directly connected to each other and have no backlash, so it is possible to move the robot arm 3 while maintaining highly accurate positioning. The guide bar 5 is held between the drive roller 10 and the pressure roller 14 by the pressure contact force as shown in FIG.
Since the guide bar 5 is configured to bend vertically and horizontally through the drive rollers 5, the guide bar 5 is displaced to follow the driving roller 10, and the rollers may hit unevenly or slip between the rollers 10 and the guide bar 5. There is no possibility that this will occur. The applicant prototyped an experimental device,
Accurate position control was possible with a maximum movement speed of 1.5m/sec.

Furthermore, in this example, the movable base 2, which is the main body of the movable base, is moved across two first guide rails 4, and the motor 7 that handles the movement is mounted on the movable base 2. As long as there is sufficient gripping force due to friction between the drive roller 10 driven by the motor 7 and the pressure roller 14 to move the guide bar 5 in a state where the guide bar 5 is held between them, even if friction occurs. However, the device can be operated without any problems and with high precision maintained.
Furthermore, even if slippage occurs between the guide bar 5 and the rollers, the movable table 2 can be regulated to an accurate movement position by the meshing between the pinion gear 22 and the rack gear 23 without backlash. In addition, the strength of the pressure contact force P mentioned above is determined by the spring 13A.
Of course, it can be changed freely by adjusting the movement mechanism itself, and the movement mechanism itself is easy to assemble and adjust, and can have sufficient durability.

In the embodiment described above, the narrow beam portion 60 is formed by providing smooth notches from all four sides, top, bottom, left and right, but the shape of the narrow beam portion formed at both ends of the guide bar is limited to this. In short, the guide bar 5 has a reduced cross-section that tends to bend and twist vertically and horizontally in response to the pressure applied from the rollers, thereby causing it to work in close contact with the drive roller 10. Needless to say, this is a good thing.

[Effect of idea]

As explained above, according to the present invention, there is a movable base that is movable on a guide rail laid on a fixed base, both ends of which are fixed to the fixed base, and are arranged in a space parallel to the guide rail. a guide bar, a drive roller that is in pressure contact with the side surface of the guide bar and is driven by a drive source provided on the movable base to move the movable base, and the guide bar is held between the drive rollers,
In the moving mechanism having the drive roller and a pressure roller that generates a pressure force against the guide bar, a reduced cross-section portion is provided near both ends of the guide bar to reduce the cross-section of the guide bar symmetrically in the vertical and horizontal directions. The reduced section section allows the guide bar to bend in the horizontal and vertical directions and twist around its neutral axis, so even if there is some deviation in the relative posture of the drive roller with respect to the guide bar, the guide will remain intact. Bars can be more easily maintained in contact with each other, like drive rollers and pressure rollers, extending the operating life of the equipment by preventing wear and tear, and also include the installation of guide bars. This also makes the entire assembly process easier.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an example of the configuration of the moving mechanism of the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a perspective view schematically showing the drive system in Fig. 1. FIG. 4 is an explanatory diagram of a defective state in a conventional moving mechanism. 1... Fixed base, 2... Moving table, 3... Robot arm, 4... First guide rail, 5...
(Second) Guide rail, 7...Servo motor, 7
A... Drive shaft, 8... Support stand, 10... Drive roller, 12... Pressure roller member, 13... Spring storage member, 13A... Spring, 14... Pressure roller, 2
1...Encoder, 22...Pinion gear, 23
... Rack gear, 50 ... Fixed pin, 60 ... Narrow beam part.

Claims (1)

[Scope of Claim for Utility Model Registration] A movable base that is movable on a guide rail laid on a fixed base, and a guide that has both ends fixed to the fixed base and is arranged in a space parallel to the guide rail. a drive roller that presses against a side surface of the guide bar and is driven by a drive source provided on the movable base to move the movable base; the guide bar is sandwiched between the drive roller; In the moving mechanism, the driving roller includes a pressing roller that generates a pressing force against the guide bar, wherein a cross section of the guide bar is symmetrically reduced in the vertical and horizontal directions near both ends of the guide bar. A moving mechanism characterized in that a reduced section is provided, and the reduced section allows the guide bar to be deflected in the horizontal and vertical directions and twisted about its neutral axis.