JPH0328146B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC motor, and more particularly to a DC motor designed to improve torque control.

Conventionally, when changing the generated torque in one DC motor, the torque could only be obtained within a limited range. The torque of a DC motor is as follows: generated torque is T, magnetic flux is Φ, armature current is a, and torque constant is
If K _T , then T=K _T Φa. Therefore, the generated torque is proportional to the magnetic flux Φ and the armature current a. Regarding magnetic flux Φ, the magnetic flux is saturated and becomes constant, the thickness of the core cannot be made very large, and when driving a DC motor, it is generally required to drive it with less current and lower voltage. For this reason, the setting range of the torque constant becomes very narrow, and as a result, the range of torque control becomes narrow as described above.

Therefore, DC motors are also used in which multiple armatures are arranged close to each other on a common rotating shaft, and the excitation of each armature is switched and controlled, and the torque constant is varied to perform torque control. If a plurality of armatures are provided on the same axis, the motor itself becomes large and is inconvenient to handle.

It is an object of the present invention to provide a DC motor that can perform the above-mentioned torque control over a wide range, and that has a compact motor configuration and is easy to handle. That is, a concentric cylindrical second rotating shaft is rotatably attached to the first rotating shaft via a bearing, and a concentric cylindrical fixed yoke outer cover is further attached to the second rotating shaft via a bearing. Attach the first
The first armature is attached to the rotating shaft of the armature, and the second armature is attached to the second rotating shaft of the
a first field coil facing the first armature is located on the second rotating shaft, and a second field coil facing the second armature is located outside the fixed yoke. further, the first rotating shaft and the second rotating shaft are separately and removably connected to a fixed part, so that one rotating shaft is alternatively rotatable and the other rotating shaft is fixed. and a switching circuit for selectively causing current to flow between the first armature and the first field coil or the second armature and the second field coil. The present invention relates to a DC motor provided therein. DESCRIPTION OF THE PREFERRED EMBODIMENTS A DC motor which is an embodiment of the present invention will be described below based on the drawings.

The figure is a side sectional view showing a DC motor according to an embodiment of the invention. This DC motor has a first armature 3 and a second armature 4 on concentric rotating shafts 1 and 2, and has a double structure as shown in the figure. Each armature is provided with an armature winding in a known manner, and each of these armature windings terminates in a commutator 9, 1, respectively.
0 commutator segments. Brush pairs 11, in contact with commutators 9 and 10, respectively;
12 are provided, and these brushes are connected to a switching circuit 15 (not shown) via connection lines 13 and 14. Around these armatures 3 and 4,
That is, the first field coil 5 and the second field coil 6 are provided in a known manner on the inner surface of the armature 4 for the armature 3, and on the inner surface of the fixed yoke jacket 16 for the armature 4, respectively. The connection wires for supplying current to these field coils 5 and 6 are also connected to the switching circuit 1 (not shown).
5. The rotating shaft 2 is provided with a clutch 7 for fixing the rotating shaft 2, and a fixed yoke outer cover 1 is provided on the rotating shaft 2.
This is fixed by connecting with 6. The base 17 is also provided with a clutch 8 for fixing the rotating shaft 1, which is fixed by being connected to the rotating shaft 1.

In the above configuration, when rotating the first armature 3, the clutch 7 is connected to the fixed yoke jacket 16 to fix the rotating shaft 2, and the switching circuit 15 is switched to apply the field to the first field coil 5. Rotation can be achieved by passing a current through the armature windings of the armature 1 via the brush 11 and the commutator 9. When the second armature 4 is to be rotated, the clutch 8 is connected to the rotating shaft 1 and fixed, and the clutch 7 is disconnected from the fixed yoke jacket 16. Then, the switching circuit 15 causes a field current to flow through the second field coil 6, and an armature current flows through the armature winding of the second armature 4, thereby making it possible to rotate the second armature 4.

Since the DC motor according to the present invention is configured as described above, the first armature and the second armature can be rotated separately. Therefore, by providing a difference in capacity, it is possible to bring about a difference in the generated torque when the rotating shafts 1 and 2 are used as power shafts. In other words, it is possible to obtain the same effect as driving small-capacity and large-capacity motors with one DC motor, and the control range of the generated torque can be made wider than with the conventional single DC motor. Furthermore, compared to the case where a plurality of electric motors are connected coaxially, the electric motor can be integrated and constructed more compactly, and handling becomes easier.

As described above, according to the present invention, it is possible to provide a DC motor that is easy to handle and can perform a wide range of torque control with a single DC motor.

It should be noted that the present invention is not limited to the above-mentioned embodiment, but may be constructed so that the clutches for fixing the rotating shafts 1 and 2 can be interlocked.

[Brief explanation of the drawing]

The figure is a side sectional view showing a DC motor according to an embodiment of the invention. 1, 2... Rotating shaft, 3... First armature, 4... Second armature, 5... First field coil, 6... Second field coil, 7, 8... Clutch, 16... Fixed yoke outer cover .

Claims (1)

[Claims] 1. A concentric cylindrical second rotating shaft is rotatably attached to the first rotating shaft via a bearing, and a concentric cylindrical fixed yoke jacket is further attached to the second rotating shaft via a bearing. At the same time, a first armature is provided on the first rotating shaft and a second armature is provided on the second rotating shaft, and the first field coil facing the first armature is connected to the second rotating shaft. A second field coil facing the second armature is attached to the fixed yoke outer sheath on the shaft, and the first rotating shaft and the second rotating shaft are each separately engaged with and detached from the fixed part. A clutch is provided that is freely coupled to selectively allow one rotating shaft to rotate and fix the other rotating shaft, and the first armature and the first field coil or the second armature are connected to each other. A DC motor provided with a switching circuit that selectively causes current to flow through the second field coil.