JPH0529573Y2 - - 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]

The applicant previously proposed a moving mechanism that can run with a guide bar held between them using the frictional force of rollers as a means for performing linear motion at high speed and with high precision. (See 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 through 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,
It is generally difficult to accurately align and mount the guide rails to move the guide bar and the moving platform that is placed between them in a straight line, and if the parallelism is even slightly off, the movement The drive roller on the table is slightly separated from the guide bar, reducing the contact force and causing slippage. or the drive roller is slightly close to the guide bar,
There were disadvantages in that the contact force increased, the surface pressure increased, and the life of the drive roller and guide bar was deteriorated.

The purpose of the present invention is to focus on the above-mentioned conventional problems, and to solve them, the movable table is made to run while the guide bar is always kept tightly sandwiched between the drive roller and the pressure roller. The object of the present invention is to provide a moving mechanism that can extend the life of the entire device.

[Means to solve the problem]

In order to achieve such an object, 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 with a rectangular cross section provided, and a side surface of the guide bar in pressure contact;
a drive roller that is driven by a drive source provided on the movable base to move the movable base; two pressure rollers disposed on opposite sides of the drive roller so as to sandwich the guide bar; a pressing force generating means for generating a pressing force that presses the driving roller against the guide bar by pressing a pressing roller against the guide bar; and a pressing force generating means disposed along a center line near both end support portions of the guide bar; The present invention is characterized in that it includes means for allowing displacement of the guide bar in the horizontal direction, which includes a substantially oval or rectangular through hole that vertically passes through the guide bar.

[Effect]

According to the present invention, a substantially oval or rectangular penetrating portion is formed vertically in the vicinity of the support portions at both ends of the guide bar which is held between the driving roller and the pressing roller by the pressing force generated by the pressing force generating means. Since the hole is drilled so that the entire guide bar can be displaced horizontally through the through hole, the guide bar is displaced in accordance with the pressing force transmitted from both rollers. It is possible to bring the drive roller and pressure roller into close contact with the bar, preventing changes in the pressure force of the rollers, extending the operating life of the device, and making it easier to drill holes with less effort. It also contributes to cost reduction.

〔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 is movable vertically is further provided on the running member.

Reference numeral 4 denotes a guide rail arranged on the moving table 2, and as shown in FIG. 2, two guide rails 4 are arranged in parallel. Further, in FIG. 1, 5 is 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 fixed by bar fixing members 6 and as described above. It is guided so as to pass through the space between the upper constituent plate 2A and the lower constituent plate 2B of the movable table 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 driving 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.

Therefore, in this example, as shown in FIG. 1, smooth curved oval or rectangular through holes 70 are bored in the center of each of the guide bars 5 having a rectangular cross section near the support portions at both ends. The through hole 7 is opened so that two vertical beams are left on the outer side of the hole 70.
0 so that the entire guide bar 5 is easily displaced in the horizontal direction as shown by arrow N.

By configuring the guide bar 5 in this way, even if the relative mounting positions of the driving roller 10 and the pressure roller 14 with respect to the guide bar 5 are somewhat poor due to assembly errors or the like and there is a tendency for uneven contact to occur, the entire guide bar 5 can be easily fixed. is displaced correspondingly,
It can be maintained in a state where it is easily held between the drive roller 10 and the pressure roller 14.

4A and 4B show the through hole 70 described above.
An example of the form is shown below.

In this example, the guide bar 5 has a thickness of 25 mm and a width of 30 mm.
As shown in the figure, a rectangular through hole 70 of 20 x 50 mm is drilled, and fillets with a radius R = 5 mm are attached to the four corners of the hole 70.
A beam portion 70A having a length of 25 mm and a depth of 25 mm was formed. Therefore,
This allows the entire guide bar 5 to be easily displaced, for example, into the form shown by the one-dot chain line.

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 be able to be displaced in the horizontal direction via the beam portions 70A on both outer sides thereof, the guide bar 5
The rollers will not hit unevenly. The applicant prototyped an experimental device and was able to implement accurate position regulation at a maximum movement speed of 1.5 m/sec.

Furthermore, in this example, the movable base 2, which is the main body of the movable body, 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, one approximately rectangular through hole was formed along the center line of the guide bar, but the shape of the through hole formed near both ends of the guide bar is not limited to this. Not, also,
For example, the shape of the guide bar 5 may be such that two through holes are formed symmetrically with respect to the center line, and the point is that the entire guide bar 5 is easily displaced only in the horizontal direction in response to the pressing force received from the rollers, and is brought into close contact with the drive roller 10. It goes without saying that any form of through-hole may be used as long as the beam portion is formed so as to generate action.

(Effects of the invention) As explained above, according to the 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 a movable base that is movable on a guide rail laid on a fixed base. a guide bar with a rectangular cross section arranged in parallel in a space; 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; two pressure rollers disposed on opposite sides of the drive roller so as to sandwich a guide bar; and by bringing the two pressure rollers into pressure contact with the guide bar, a pressure contact force is generated that causes the drive roller to come into pressure contact with the guide bar. and a substantially oval or rectangular through hole that is disposed along the center line near both end support portions of the guide bar and that vertically passes through the guide bar. Since the guide bar is equipped with a means for allowing displacement in the direction, even if the relative mounting positions of the guide bar and the guide rail are slightly shifted, the guide bar can easily maintain contact between them in the same way as the drive roller and the pressure roller. It has become possible to extend the operating life of the device by preventing wear and tear, and also to facilitate the overall assembly work including the installation of the guide bar.

[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. 4A and 4B are a side view and a plan view, respectively, showing an example of the guide bar and its through hole according to the present invention. 1... Fixed base, 2... Moving table, 3... Robot arm, 4... First guide rail, 5...
(Second) Guide bar, 7...Servo motor, 7A
... 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, 70...Through hole, 70A...Beam part.

Claims (1)

[Claims for Utility Model Registration] A movable platform that is movable on a guide rail laid on a fixed platform, and a rectangular shape having both ends fixed to the fixed platform and arranged in a space parallel to the guide rail. a cross-sectional guide bar; 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; and a drive roller that sandwiches the guide bar. two pressure contact rollers disposed on opposite sides; a pressure contact force generating means for generating a pressure contact force that presses the drive roller against the guide bar by bringing the two pressure contact rollers into pressure contact with the guide bar; and the guide bar. means for allowing displacement of the guide bar in the horizontal direction, comprising a substantially oval or rectangular through hole that is disposed along the center line near both end support portions of the guide bar and vertically passes through the guide bar; A moving mechanism characterized by comprising: