JPS63220752A - Dc servo-motor of permanent magnet type - Google Patents

Abstract

PURPOSE:To lessen the delay of the rotational action at the time of starting a motor due to provision of a guide cylinder, by using thin nonmagnetic sheet material for the guide cylinder that is placed between a permanent magnet and an armature. CONSTITUTION:On the inner peripheral surface of a yoke 1, a permanent magnet 2 is fitted integrally and firmly. On an armature 3, a core shaft 4 is supported rotatably and pivotally. A guide cylinder 7 for insertion-guiding the armature 3 into is fitted on the yoke 1 so that the inner peripheral surface of the permanent magnet 2 may be pressed in, and is placed between the permanent magnet 2 and the armature 3. The guide cylinder 7 is formed with non-magnetic material, for example, the sheet material of aluminum.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a permanent magnet type DC servo motor that is driven by controlling substantial electric power by an open/call switching mode of a DC power supply. .

[Prior Art and Problems to be Solved by the Invention] In general, some permanent magnet type DC servo motors have a DC power supply in an ON-call switching mode, and substantial power control is performed by changing the duty ratio of the ON time. Some devices are designed to drive with torque depending on the load condition. However, in this case, when assembling the motor, sometimes when inserting the armature into the inner circumferential side of the permanent magnet, the armature may come into contact with the permanent magnet and the surface may be scratched or deformed. . As shown in Figure 2, the items with these scratches, etc.
This poses a problem because the cogging component of the friction torque that occurs when the motor output shaft is rotated by an external force increases and smooth rotation is obstructed. Therefore, it may be possible to interpose a guide tube between the permanent magnet and the armature to guide the insertion of the armature to prevent damage when inserting the armature, but in this case, the performance decreases due to the provision of the guide tube. It is necessary to suppress the rotation as much as possible, especially in the case where the speed of rotation start-up at the time of starting the motor is required and the required torque must be generated in a short period of time. What happens is not good.

[Means for solving the problem] In view of the above-mentioned circumstances, the present invention was devised for the purpose of providing a permanent magnet type DC servo motor that can eliminate these drawbacks. Power supply 0111-(In a permanent magnet DC servo motor that is driven with substantial power control by IF switching mode, a guide cylinder is provided between the permanent magnet and the armature to guide insertion of the armature. The guide tube is characterized in that it is formed of a thin plate made of a non-magnetic material.

With this configuration, the present invention eliminates the delay in the start-up time at the time of startup, even though the armature insertion guide tube is provided.

[Embodiment] Next, an embodiment of the present invention will be explained based on the drawings. In the drawing, 1 is a yoke of a permanent magnet DC servo motor, and the inner peripheral surface of the yoke 1 has a permanent magnet 2. are integrally fixed. 3 is an armature in which a core shaft 4 is rotatably supported.

Reference numeral 5 denotes a commutator with which the brush 6 comes into sliding contact, and all of these members are constructed in the conventional manner.

On the other hand, 7 is a guide tube that guides the insertion of the armature 3, and the guide tube 7 is fitted into the yoke 1 by press-fitting the inner peripheral surface of the permanent magnet 2, so that the permanent magnet 2 and the armature The material is interposed between 3 and 3.
It is made of aluminum, which is a typical example of non-magnetic material.

The motor is driven with the necessary torque corresponding to the load by substantially controlling the power by changing the duty ratio of the open time by the open-gang switching mode of the DC power supply.

Next, we will show how effective the present invention is when a similar guide tube is formed using the guide tube 7 according to the above embodiment and iron, which is a magnetic material, and is installed under the same conditions. The rise time of the amateur current is measured and compared using equipment such as an oscilloscope. In this case, as a comparison of measurement results, one time constant τe was studied. When comparing this time constant τe by actual measurement, it is found that the time constant τe of the present invention in which the guide ft17 is made of aluminum.

It was 2.1+ms (milliseconds), but the iron one was 2.8+w, which is 0.7 compared to the aluminum one.
The singing was also slow. From these facts, it becomes clear how effective it is to make the guide tube 7 of the present invention from a non-magnetic material such as aluminum. The time constant τe is shortened by making the guide tube 7 a non-magnetic material.When the guide tube 7 is made of a magnetic material, the inductance of the armature 3 is
It can be inferred that this is due to the increase in magnetic permeability of the guide tube near the

In addition, in the present invention, the material of the guide tube only needs to be non-magnetic, so other metals such as copper can be used, and problems such as strength, heat resistance, processing accuracy, etc. can be solved. If so, a resin material may be used.

[Operation and Effect] In summary, since the present invention is constructed as described above, the armature can be inserted without contacting the permanent magnet and being damaged by the guide tube arranged on the inner circumferential side of the permanent magnet. Although it is capable of smooth rotation with low cogging torque, the guide tube is made of non-magnetic material, so it is possible to apply a power supply current in ON-OFF switching mode to the servo motor and avoid sudden voltage changes. In this case, the time constant of the rotational speed can be made smaller than when the cylinder is made of magnetic material. Therefore, the delay in the rotation start-up speed when starting the motor due to the provision of the guide cylinder can be reduced. This means that we can provide high-quality servo motors that are as compact as possible and have good performance.

[Brief explanation of the drawing]

The drawings show an embodiment of the permanent magnet type DC servo motor according to the present invention, in which Fig. 1 is a partially cutaway front view of the servo motor, and Fig. 2 A and B show scratches on the armature. Figure 3 A and B are measurements showing the relationship between starting time and armature current when the guide tube is made of aluminum or iron. This is a diagram of the results. In the figure, 1 is a yoke, 2 is a permanent magnet, 3 is an armature, and 7
is a guide tube. Patent applicant Mitsu Wit Machine Manufacturing Co., Ltd. No. 2 A

Claims (1)

[Claims] In a permanent magnet type DC servo motor that is driven with substantial power control by the ON-OFF switching mode of the DC power supply, there is a gap between the permanent magnet and the armature.
A permanent magnet DC servo motor, characterized in that a guide tube is provided for guiding the insertion of the armature, and the guide tube is formed of a thin plate made of a non-magnetic material.