JPS60155051A - Electrically-driven rectilinear motion actuator - Google Patents

Abstract

PURPOSE:To reduce assembling labor hour by providing an actuator comprising a rotor having a pipe-like shaft and a screw shaft inserted in the shaft, which are individually formed. CONSTITUTION:A rotor 4 is fixed to a pipe-like shaft 15. A screw shaft 16 has a screw portion 16a comprising a ball screw or a trapezoidal thread at the one end thereof and a worm gear 16b mounted at the other end thereof, and fixed to the shaft 15 to be united in a body. Under the cover 17, there is a bearing 7 for supporting the screw shaft 16 provided at the central portion and a detent pin 14 for regulating the motion of a nut 12 in the turning direction. As the shaft 15 of the rotor 4 is pipe-like, the nut 12 and the screw shaft 16 can be assembled in separate processes as a ball screw or a trapezoidal thread so as to reduce the assembling labor hour.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric linear motion actuator that drives an object to be operated by reciprocating an output shaft with finite rotations by rotating an electric motor in the forward and reverse directions.

Conventional configurations and their problems In recent years, there has been a trend in construction machinery such as bulldozers to use electric linear motion actuators to operate the axial pressure control valves to reduce the burden on the driver and to achieve unmanned movement. .

2-, - The conventional electric linear motion actuator as described above will be described below with reference to the drawings.

FIG. 1 shows a conventional electric linear motion actuator. In FIG. 1, 1 is a frame having a permanent magnet 2 fixed to its inner peripheral surface, and 3 is a rotor 4 facing the permanent magnet 2.
The shaft has a threaded portion 3a made of a ball screw or a trapezoidal screw at one end, and a ukumu 3b at the other end.

6.6 is a placket attached to both ends of the frame 1, and the shaft 3 is rotatably supported by a bearing installed in the medium heat section. 8 is a brush that comes into sliding contact with the commutator 9; 1o is a potentiometer that detects the amount of rotation of the shaft 2;
Covered by 1.

Reference numeral 12 denotes a ball screw or trapezoidal screw nut that is screwed into the threaded portion 3a of the shaft 2, and an axial groove 12& is provided on the outer circumferential surface, and a rotation stopper 14 provided on the motor mounting base 13 is engaged with this groove 12a. [7]

In the above configuration, when the electric motor is rotated and also rotated in the forward and reverse directions, the nut 12 repeats reciprocating motion in the direction of the arrow because movement in the rotational direction is restricted.

However, in the electric linear motion actuator configured as described above, since the shaft 3 and rotor 4 are integrated, there are the following drawbacks in terms of assembly. First, in order to machine the rotor, first machine the threaded part 3a that engages with the nut 12 of the shaft 3, then assemble the rotor 3 on the shaft 2, and then assemble the frame 1, brackets 5, 6.
Combine them together to form a motor, and then attach nut 1 to threaded part 3a.
2 has to be assembled, making it impossible to shorten the assembly man-hours, and from a quality control perspective, there is a disadvantage that the threaded portion 3a is easily damaged due to the large number of movements between processes.Objective of the Invention The present invention The present invention eliminates the above-mentioned drawbacks and provides an inexpensive, high-quality electric linear motion actuator.

Structure of the Invention To achieve this object, the electric linear motion actuator of the present invention includes a rotor having a pipe-shaped shaft, and a screw shaft having a ball screw or trapezoidal screw at one end that is inserted or press-fitted into the shaft. By making the rotor and screw shaft separately, the screw part is less likely to be damaged, and the rotor and screw shaft can be assembled in the final process, so there is no need to worry between the processes. The number of man-hours can be reduced by reducing the amount of movement required, and an inexpensive, high-quality electric linear motion actuator can be provided.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows the configuration of an electric linear motion actuator in an embodiment of the present invention. Components that are the same as those in the conventional configuration described above are given the same numbers, and their explanations will be omitted. In FIG. 2, 16 is a pipe-shaped shaft to which the rotor 4 is attached.

16 is a threaded portion 1 consisting of a ball screw or a trapezoidal screw at one end.
6a, and the other end is provided with a woom 16b, and is integrally fixed to the shaft 15. A detent pin 14 for regulating the movement of the nut 12 in the rotational direction is attached under a cover equipped with a bearing 7 supporting the screw shaft 16 in the center. 18 is a cover equipped with a bearing 7 supporting the screw shaft 16 in the center, and a lid 19 forms a space in which the potentiometer 10 is housed. According to the second configuration, the rotor 4 is By making the shaft 16 into a pipe shape, the nut 12 and the screw shaft 16 can be assembled as a ball screw or trapezoidal screw in a separate process. Therefore, in the final step, the screw shaft 16 is inserted or press-fitted into the shaft 16, and the shaft is assembled. If it is fixed integrally with 16, the threaded part 1ea
There is no damage to the surface, and the number of assembly steps is reduced.

Effects of the Invention As is clear from the above explanation, according to the present invention, the rotor and the screw shaft can be assembled in the final process, and it is possible to prevent damage to the threaded portion, and also to reduce the time between processes. The process can be shortened by reducing the movement of
A high quality electric linear motion actuator can be obtained at low cost.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional electric linear motion actuator.
FIG. 2 is a sectional view of an electric linear motion actuator in an embodiment of the present invention. 4... Rotor, 12... Nut, 15
...Shaft, 16...Screw shaft, 16a...
...Screw part.

Claims (1)

[Claims] an electric motor having a rotor fixed to a pipe-shaped shaft; a threaded shaft inserted and fixed into the pipe-shaped shaft and having a threaded part made of a ball screw or a trapezoidal thread at one end; , and a nut that moves in the axial direction in conjunction with the rotation of a screw shaft.