JPH0523980A - Rectilinear robot - Google Patents

Abstract

PURPOSE:To provide such a rectilinear robot as in a structure that length of a connecting member, connecting a motor shaft and a feed screw shaft, will in no case turn to a dead space. CONSTITUTION:Turning effort of a motor shaft 23 is transmitted to a feed screw shaft 16 via a connecting member 20. A slider 15 shifting along a rectilinear guide 21 has a feed nut 17 being screwed in the feed screw shaft 16, and a recess 28 made up of eliminating a screwed part with an inner diameter larger than an outer diameter of the connecting member 20 up to almost the same depth as length of this connecting member, from the end of a flange part 18 at the motor side, is installed in this feed nut 17, through which the length of the connecting member 20 will in no case turn to a dead space so as to make this connecting member 20 stowable in the space, that is a main feature of this rectilienar robot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectilinear robot corresponding to one axis of a Cartesian coordinate type robot for precision assembly work such as transfer and insertion of parts.

[0002]

2. Description of the Related Art As a robot for flexibly performing precision assembling work, a rectangular coordinate type robot as shown in FIG. 3 is often used together with a SCARA type robot as shown in JP-A-59-146778. .. This rectangular coordinate type robot is configured by combining two or three rectilinear robots driven by servomotors so that the operation directions are at right angles. Conventional straight-ahead robots
The structure is as in Japanese Patent Application No. 2-335890, and its exploded perspective view is shown in FIG. 4 and its sectional view is shown in FIG. Figure 4
Further, in FIG. 5, reference numeral 1 is a slider, and a feed nut 3 screwed onto the feed screw shaft 2 is fixed by a flange portion 4. The rotation of the AC servomotor 5 is transmitted to the feed screw shaft 2 via the connecting member 6, and the slider 1 moves straight
Move along. The amount of movement is controlled by passing a current through the AC servomotor 5 while comparing a program stored in advance in a controller (not shown) with a rotation angle signal sent from the rotary encoder 8.
By rotating. The motor shaft 9 includes an angular bearing 11 incorporated in a motor bracket 10 and a deep groove ball bearing 13 incorporated in a motor housing 12.
Thus, it is rotatably supported without any clearance in the axial direction and the direction perpendicular to the axis. The feed screw shaft 2 is a ball screw that is screwed with the feed nut 3 via a hard ball. One end of the feed screw shaft 2 that is not connected to the connecting member 6 is a deep groove ball bearing 14 in order to increase the resonance point of the shaft so that it can rotate at high speed. We support.
The feed nut 3 is fixed to the slider 1 by the flange portion 4 of the feed nut 3 provided on the AC servomotor 5 side. When fixed to the motor side, it is necessary to separate the feed nut 3 and the feed screw shaft 2 once during assembly. As in this example, in a straight-ahead robot that often uses a ball screw as the feed screw shaft, This is because there is a risk of problems such as falling off and the workability is very poor.

[0003]

In the robot constructed as described above, a dead space is generated by the length of the connecting member 6, which is a major obstacle to the miniaturization and weight reduction of the robot. Has become.

In view of the above problems, it is an object of the present invention to provide a straight-ahead robot which eliminates a dead space and is small and lightweight.

[0005]

In order to achieve the above-mentioned object, a straight-moving robot according to the present invention has a feed nut from an end surface of a flange portion to an inner diameter larger than an outer diameter of a connecting member to a depth of about the longitudinal direction of the connecting member. A recess is provided by removing the screwed portion.

[0006]

With the above construction, when the slider moves to the motor side, the connecting member connecting the motor shaft and the feed screw is housed in the recess provided in the feed nut, so that the feed nut and the connecting member do not interfere with each other. Therefore, the slider can move to a position where it hits the motor, and dead space due to the connecting member does not occur.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an embodiment of a straight ahead robot of the present invention, and FIG. 2 is a partial sectional view thereof. In FIGS. 1 and 2, reference numeral 15 denotes a slider, which is a feed screw shaft 1
A feed nut 17 that is screwed onto the screw 6 is fixed by a collar portion 18. The rotation of the AC servo motor 19 is transmitted to the feed screw shaft 16 via the connecting member 20, and the slider 15 moves along the linear guide 21. The movement amount is controlled by passing a current through the AC servo motor 19 and rotating the motor shaft 23 while comparing a program stored in advance in a controller (not shown) with a rotation angle signal sent from the rotary encoder 22. The motor shaft 23 is rotatably supported by an angular bearing 25 incorporated in the motor bracket 24 and a deep groove ball bearing 27 incorporated in the motor housing 26, without any gap in the axial direction and the direction perpendicular to the axis. The feed screw shaft 16 is a ball screw that is screwed with a feed nut 17 via a hard ball. The feed nut 17 has a recess 28 as shown in the axial cross section of FIG.
Even if the slide table 15 moves to a position where it interferes with 9, the connecting member 20 and the feed nut 17 do not interfere.

[0008]

According to the straight-ahead robot of the present invention, the dead space in the longitudinal direction, which cannot be avoided by the conventional feed screw shaft and the connecting member, can be eliminated, the installation space can be minimized, and the area productivity can be improved. The economic effect is enormous.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a rectilinear robot of the present invention.

FIG. 2 is a partially enlarged sectional view of an embodiment of a straight-ahead robot of the present invention.

FIG. 3 is a perspective view of a conventional rectangular coordinate type robot.

FIG. 4 is an exploded perspective view of a first example of a conventional straight-ahead robot.

FIG. 5 is a sectional view of a first example of a conventional straight-ahead robot.

FIG. 6 is a sectional view of a second example of a conventional straight-ahead robot.

[Explanation of symbols]

 15 Slider 16 Feed screw shaft 17 Feed nut 18 Collar 19 AC servo motor 20 Connecting member 21 Straight guide 22 Rotary encoder 23 Motor shaft 24 Motor bracket 25 Angular bearing 26 Motor housing 27 Deep groove ball bearing 28 Recess

Claims (1)

Claim: What is claimed is: 1. A feed screw shaft arranged coaxially with a rotational force of a motor shaft which is supported and rotated so as to receive a load in an axial direction and a direction perpendicular to the shaft inside the motor housing. To a slider that moves along a linear guide provided parallel to the feed screw shaft, and a feed nut screwed to the feed screw shaft is provided on the motor shaft side of the feed nut. In a straight-moving robot that is fixedly driven by a section, the feed nut is provided with a recess in which a threaded portion is removed from an end surface of the flange section to an inner diameter larger than the outer diameter of the connecting member to a depth of about the longitudinal direction of the connecting member. A straight-ahead robot characterized by being present.