JPH04256549A - Linear movement system - Google Patents

Abstract

PURPOSE:To prevent a position detection device detecting the position of a table from large-sizing and to restrain the high cost thereby, even in the case of the diameter of a ball screw being necessary to be increased on the durability in order to mount a large sized robot on the table, in the linear movement system which moves the table mounted with the robot along a linear guide and ball screw. CONSTITUTION:A rail 8 is provided along the progress direction of a table 4 on the side face of a linear guide 1a. On the one part a rotary body 7 which rotates while biting with the rail 8 at the moving time of the table 4 and a position detection device 6 are provided on the table 4. The position detection device 6 reads at any time the rotation angle from the reference position of the rotary body 7 at the table 4 movement time, detecting the position of the table 4 thereby. This position detection device 6 was provided inside a penetration type motor 3 in the past and to detect the table 4 position by detecting the azimuth of the penetration type motor 3, but this is directly provided on the table 4 to execute the position detection by detecting the azimuth of the rotary body 7. Consequently, it is unnecessary to enlarge even the position detecting device 6 even in case of the diameter of the ball screw 2 being enlarged.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear movement system for linearly moving a robot or the like for positioning, and more particularly to a linear movement system for moving a moving table using a through-type motor.

[0002] When a robot is linearly moved to perform precision work, it is necessary to accurately know the position of the robot's hand. To do this, it is necessary to accurately know the position of the table, which is the base of the robot.

0003

2. Description of the Related Art Conventionally, some linear movement systems are equipped with a through-type motor that moves while being screwed into a ball screw as a power source for moving a table.

FIG. 3 is a sectional view showing the structure of this through-type motor. This penetrating motor includes a cylindrical shaft 32 through which a ball screw 31 passes, and a nut 33 fixed to the cylindrical shaft 32 and screwed into the ball screw 31. A rotor 34 is fixed to the cylindrical shaft 32 and rotates forward or backward depending on the direction of the current flowing through the stator 35. As the cylindrical shaft 32 rotates, the nut 33 is screwed into the ball screw 31, thereby causing the entire penetrating motor to move straight.

[0005] The through-type motor is provided with a position detection device 36 for detecting the position to which the motor has moved. This position detection device 36 is a device called a so-called rotary encoder, and is composed of a disk 37 and a detection section 38. The disk 37 is fixed to the cylindrical shaft 32 and rotates in forward and reverse directions as the cylindrical shaft 32 rotates. This disk 37 has a plurality of slits (not shown) provided at equal intervals along its circumference. Detection section 38
constantly irradiates light onto the slit of the rotating disk 37,
The light passing through this slit is detected from the opposite side, and a pulse corresponding to the rotation angle of the cylindrical shaft 32 is output. The robot control device detects the position of the robot by counting these pulses.

[0006]

[Problems to be Solved by the Invention] By the way, when attempting to move a larger robot in a linear movement system equipped with such a through-type motor, it is necessary to increase the diameter of the ball screw 31 in order to increase the durability of the system. It needs to be bigger. However, in the conventional configuration, the ball screw 3
1, the position detection device 36 is increased accordingly.
The diameter also had to be increased, which resulted in a problem of high cost.

The present invention has been made in view of these points, and an object of the present invention is to provide a linear movement system that does not increase the size of the position detection device even if the diameter of the ball screw is increased.

[0008]

SUMMARY OF THE INVENTION FIG. 1 is a perspective view of the linear movement system of the present invention seen from below. ball screw 2
A table 4 is fixed to a through-type motor 3 that moves while being screwed together with the table 4, and a rotating body 7 that rotates while contacting the linear guide 1a as the table 4 moves, and a rotating body 7 that controls the rotation of the rotating body 7. A position detection device 6 for detecting the position of the table 4 by reading the position is provided.

[0009]

[Operation] By operating the penetrating motor 3, the table 4 on which the robot is mounted moves straight along the linear guides 1a and 1b. Since the rotating body 7 is in contact with the linear guide 1a, it rotates as the table 4 moves, and the position detection device 6 detects the position of the table 4 due to this rotation. Therefore, since it is not necessary to provide the position detection device 6 inside the through-type motor 3, the size of the position detection device 6 is not affected by the size of the ball screw 2.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the linear movement system of the present invention seen from below. This linear movement system mainly includes linear guides 1a and 1b, a ball screw 2, a through-type motor 3, and a table 4. Linear guide 1a, 1
b and the ball screw 2 are fixed at both ends by end plates 5a and 5b, respectively, so that they are parallel to each other. The through-type motor 3 has a ball screw 2 passing through a central cylindrical shaft and a nut (not shown). This penetrating motor 3 is electrically connected to a robot control device (not shown), and when the robot is working, a rotor fixed to a cylindrical shaft rotates in accordance with a control signal from the robot control device. As a result, the cylindrical shaft and nut rotate, and the penetrating motor 3 moves in either direction of arrows X or Y in the figure. The table 4 is placed on the linear guides 1a and 1b,
Its lower surface is positioned by a plurality of guide members 4a provided along the linear guides 1a, 1b. The penetrating motor 3 and the table 4 are fixed to each other and move together when the robot is working.

A position detection device 6 having a rotating body 7 is provided on the lower surface of the table 4 on the linear guide 1a side. On the other hand, on the side surface of the linear guide 1a, a rail 8 with which the rotating body 7 comes into contact when the table 4 moves is provided along the traveling direction of the table 4. The rotating body 7 is formed into a cylindrical shape, and a plurality of teeth 7a are formed at equal intervals on the side surface thereof. Moreover, the teeth 7a of the rotating body 7 are provided on the surface of the rail 8.
A plurality of teeth 8a are formed at equal intervals to mesh with the teeth 8a. In this embodiment, the rotating body 7 is a pinion, and the rail 8 is a rack. Therefore, since no slippage occurs between them during the rotation of the rotating body 7, the rotating body 7 rotates in accordance with the movement of the table 4 accurately. The position detection device 6 is, for example, a conventionally used rotary encoder, and outputs pulses corresponding to the rotation angle of the shaft of the rotating body 7. A robot control device (not shown) reads this pulse to detect the position of the table 4.

FIG. 2 is a perspective view showing an articulated robot placed on a table 4 for actually working with this linear movement system. 9 in the figure is a sensor robot,
10 and 11 are working robots. These articulated robots 9 to 11 are attached to the table 4 via a turntable 12. An optical sensor 9b is attached to the tip of the arm 9a of the sensor robot 9, and working hands 10b, 11b are attached to the tips of the arms 10a, 11a of the working robots 10, 11, respectively.

In the linear movement system of the present invention having such a configuration, the through-type motor 3 operates to move the table 4.
When the rail 8 moves, the rotating body 7 rotates while contacting the rail 8. The position detection device 6 detects the rotation angle of the shaft of the rotating body 7 from a reference position, and outputs a pulse according to the rotation angle. A robot control device (not shown) detects the position of the table 4 by reading pulses output from the position detection device 6, and controls the movement of the penetrating motor 3 and the articulated robots 9 to 11 based on this.

As described above, in this embodiment, the rail 8 is provided along the linear guide 1a, and the rotating body 7 that moves while meshing with the rail 8 is provided on the table 4, so the position detection device 6 is connected to the through-type motor. It can be provided outside of 3. Therefore, even if it is necessary to increase the diameter of the ball screw 2 for durability reasons in order to move a large robot,
There is no need to increase the size of the position detection device 6 as in the conventional case, and a standard size device can be used. Therefore, the cost is not high.

Furthermore, if the intervals between the teeth 7a and 8a provided on the rotating body 7 and the rail 8 are narrowed, the table 4
The position of can be detected more precisely. In the above embodiment, the rail 8 is a rack and the rotating body 7 is a pinion, but the present invention is not limited to this. For example, both may be made of a material with a large frictional force such as rubber. Furthermore, if each surface is provided with irregularities such as the teeth shown in this embodiment, more precise position detection becomes possible.

[0016]

As explained above, in the present invention, the table is provided with a rotating body that rotates while contacting the linear guide as the table moves, and the position of the table is detected from the rotation of the rotating body. There is no need to provide a position detection device inside the through-type motor. Therefore, even if it is necessary to increase the diameter of the ball screw for durability reasons in order to place a large robot on the table, there is no need to increase the size of the position detection device as in the past, and a standard size one can be used. Can be done. Therefore, the cost is not high.

[Brief explanation of the drawing]

FIG. 1 is a perspective view from below of a linear movement system of the present invention.

FIG. 2 is a perspective view showing an articulated robot placed on a table.

FIG. 3 is a diagram showing the configuration of a conventional through-type motor.

[Explanation of symbols]

1a, 1b Linear guide 2 Ball screw 3 Through-type motor 4 Table 6 Position detection device 7 Rotating body 8 Rail

Claims (2)

[Claims] Claim 1: In a linear movement system in which a table (4) on which a robot is mounted linearly moves along linear guides (1a, 1b) and a ball screw (2), the table (4) moves while being threadedly engaged with the ball screw (2). a through-type motor (3) that moves the table (4) by moving the table (4); and a rotating body (3) that is provided on the table (4) and rotates while contacting the linear guide (1a) as the table (4) moves.
7), and the rotating body (7) provided on the table (4).
) by reading the rotation angle of the table (4).
A linear movement system characterized by having a position detection device (6) that detects the position of. 2. The linear guide (1a) includes a rail (8) on which the rotating body (7) moves while contacting the linear guide (1a).
), and a plurality of teeth (7a), (8a) that mesh with each other are provided at equal intervals on the contact surfaces of each of the rotating body (7) and the rail (8). The linear movement system according to claim 1.