JPS5828633A - Torque detecting spring - Google Patents

Abstract

PURPOSE:To obtain a torque detecting spring which can be easily produced with high accuracy of detection and can increase the lifetime of a bearing, by setting a pitch angle at zero for the deformed part of the elasticity of a coil spring. CONSTITUTION:An oval gap 1d is provided at an elastic deformed part 1c formed between an attachment part 1a at the main shaft side and an attachment part 1b at the rotor side and in the bus direction so that a C-shaped ring of <=1 turn with the pitch angle of zero. The holes 1e and 1f are drilled at the upper and lower parts of the edge of the gap 1d and coupled to the gap 1d via the grooves 1g and 1h formed along the plane which is orthogonal to the axial core of a spring. In such constitution, the production is facilitated, the distance is reduced between the fixed parts of both ends to decrease the bending moment owing to the pitch angle of zero, and as a result the lifetime is increased for the bearing due to the increase of the detecting accuracy and the even force to be given to the bearing respectively for the torque detecting spring.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a torque detection spring in a coil spring type rotating body torque measuring device.

An induction motor with a built-in torque needle has been developed as a drive machine for monitoring processing of machine tools, etc., and one of the methods is a coil spring method.

In this method, the attachment part at one end of the coil spring is attached to the rotor shaft, which is coaxial with the main shaft of the motor and rotatable relative to the main shaft, and the attachment part at the other end is attached to the main shaft. The purpose is to detect the torque applied to the main shaft by detecting the angular deviation between the two numbered parts.

Conventionally, the torque detection spring used in this torque detection method has an elastically deformed portion in a spiral shape as shown in Fig. 1, which is difficult to manufacture and process. Since the widths are almost the same, the outer shape of the entire spring becomes larger due to the space of the groove, and therefore, there is a drawback that the torque in the motor etc. and the ratio of the space occupied by the detection section (1) becomes large. Furthermore, a mechanical problem with conventional spiral coil springs is that the elastic deformation part has a pinch angle, which increases the distance between the mounting parts at both ends. (When the spiral elastic deformation part is twisted, a stress occurs that causes the axes of the mounting parts at both ends to become misaligned, and this stress bends the spring mounting shaft along its longitudinal direction.) To detect the torsion angle between the ends of the coil spring (which acts as a bending moment), the position of the detection plate attached to both ends of the coil spring and the pink amplifier installed close to this detection plate is As a result, detection accuracy deteriorates, and the force applied to the bearing (especially the drive-side bearing) becomes unbalanced with respect to the shaft center.
This has the disadvantage of damaging the bearing and shortening its life.

The present invention eliminates problems in manufacturing, processing, and space by making the pitch angle of the elastically deformed portion of the coil spring zero, and also reduces the bending moment acting on the shaft to improve detection accuracy. It is an object of the present invention to provide a torque detection spring that extends the life of a bearing.

Hereinafter, the present invention will be explained based on an embodiment. Figs. 2 and 3 show the configuration of the torque detection spring +11 according to the present invention, and show the main shaft side mounting part (1a) and the rotor side mounting part (1a). The elastically deformable portion (IC) formed between the mounting portion (1b) is configured to have a C-shaped ring shape with a pinch angle of zero and less than one turn. In the process, an elliptical gap (1d) is created in the cup-shaped base material along the generatrix direction, and holes (l e) and (1f) are opened above and below the ends of the gap. , a groove (Ig) along a plane perpendicular to the axis of the spring so that the hole and the gap (1d) are connected, (1
It is preferable to form h).

Fig. 4 shows an embodiment of the induction motor incorporating the torque detection spring described above. There are needle bearings (5) and bearings (6) on the outer periphery of the main shaft +21.
The rotor shaft (7) is rotatably supported by.

The main shaft (2) has the coil spring (11 mounting part (1a)
is fixed, and the other attachment part of the same coil spring 01 (
1b) is fixed to one end of the rotor shaft (7).

The mounting parts (1a) and (1b) each have a first and a second
Detection plate +81. (91 is attached, and salient poles (8a) and (9a) are formed on the circumference of each detection plate at indexed angular positions that equally divide two circumferences. Also, the motor casing (3) includes the first and second detection plates +81.
．． The first and second detection elements (10) are in close proximity to the respective salient poles (8a) and (9a) of +91,
(11) is fixed. In the figure (12) is the rotor,
(13) indicates a stator.

The detection elements (10) and (11) are salient poles (8a),
(9a) is configured to generate one pulse each time it passes, and as is already known, there are types that detect changes in magnetic flux, electric value induction type, and electrostatic induction type. , or a photoelectric type can be used.

FIG. 5 is a block diagram showing the configuration of a torque measuring device using the torque detecting spring of the present invention, in which a detecting element (10
), (11) is a pair of yokes (10a).

(lla), coils (10b) and (Ilb) that are wound around this yoke to detect changes in magnetic flux, and a magnet (10c) that forms a magnetic circuit between the date and the detection plate.

(llb), yoke (10a), (lla
) is a salient pole (8a) in which a pair of magnetic materials is provided on the outer periphery of a first detection plate (8) and a second detection plate (9), respectively;
They are provided close to each other at the same interval as the pitch of (9a). Therefore, when the rotor shaft 17) rotates, a sine wave with a frequency corresponding to the rotational speed of the first detection plate (8) and the second detection plate (9) is transmitted to the first and second detection elements (10) and (11
) are output from the waveform shaping circuits (21) and (22), respectively.
) is shaped into a rectangular wave by the 2 time difference detection circuit (23
), and is configured to output a force corresponding to the phase difference between the two detected waveforms. That is, when the load torque increases, the first detection plate (8) on the driving side is
), the rotational phase of the second detection plate (9) on the load side is delayed, and conversely, when decelerating, etc., the second detection plate (9) is delayed due to the moment of inertia on the load side.
The rotational phase of the detection plate (9) advances, and an electric signal corresponding to the phase time difference is output from the time difference detection circuit (23).
It is output together with the lead/lag sign. Then, the output is amplified by the next amplifier (24), and by selecting the degree of amplification to a desired value, an output converted into a torque value can be obtained.

As described above, the present invention provides an elastically deformable portion of a coil spring,
By providing a gap in the circumferential direction between the connection parts with the mounting parts at both ends, the ring is formed into a C-shaped ring with a pitch angle of less than -1 and a pitch angle of zero, thereby producing the following effects.

- Since the pinch angle is zero, the distance between the fixed parts at both ends can be shortened, which is advantageous in terms of space.

- Since the distance between the fixed parts at both ends of the coil spring can be shortened, the bending moment acting on the shaft can be reduced, reducing the positional shift of the salient pole of the detection plate, and improving detection accuracy.

■ Since the bending moment can be reduced, the force on the bearing can be evenly distributed around the shaft center, extending the life of the bearing.

■ Since the pitch angle is zero, it is easier to manufacture than conventional spiral-shaped ones, and is advantageous in terms of manufacturing and processing.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a conventional torque detection spring, Fig. 2 is a side view showing an embodiment of the torque detection spring according to the present invention, and Fig. 3 is a sectional view taken along line 1-1 in Fig. 2. FIG. 4 is a top sectional view showing an embodiment of an ink drive motor incorporating a torque detection spring of the present invention, and FIG. 5 is a block diagram showing the configuration of a torque measuring device. Patent applicant Yaskawa Electric Co., Ltd. Agent Sunshi Ito (and 1 other person)

Claims (1)

[Claims] 1. A coil spring whose mounting part at one end is fixed to the driving side of a rotating body and the mounting part at the other end is fixed to the driven side of the rotating body, and the transmitted torque is detected by the size of its torsion angle,
The elastic deformation part of the coil spring is formed into a C-shaped ring shape with less than - winding and a pitch angle of zero by providing a gap in the circumferential direction between the connecting parts with the mounting parts at both ends. Torque detection spring.