JPH0525338U - Torque sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention is a conversion mechanism that detects torque by converting relative rotation between a main shaft and a driven shaft in the axial direction of a slide cylinder, and the structure of the conversion mechanism is simple and compact. In order to improve the torque detection accuracy, a highly reliable torque sensor is provided. [Structure] A slide cylinder 10 facing a displacement detector 13 is provided movably in the axial direction on the outer periphery of at least one of a main shaft 5 and a slave shaft 3, and is rotated by relative rotation between the main shaft 5 and the slave shaft 3. Sensor shafts 5a and 3a which are alternately meshed so as to approach and separate from each other in the direction are formed on the driving shaft 5 and the driven shaft 3, and the end faces of the sensor shafts 5a and 3a on the driving shaft 5 side and the driven shaft 3 side are circumferentially arranged. And a flexible plate 8 that is in contact with the end surface of the slide cylinder 10 and is connected to the flexible plate 8.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a torque sensor suitable for a steering device of an automobile.

[0002]

[Prior Art]

 As one of the torque sensors of this type, a main shaft and a driven shaft are connected to each other via a torsion bar so that they can rotate relative to each other, and a slide cylinder can be axially moved around the outer periphery of either the main shaft or the driven shaft. The three points of the transmission plate are connected to the driving shaft, the driven shaft and the slide cylinder at a plurality of angular positions on the outer periphery of the driving shaft and the driven shaft, and the relative rotation between the driving shaft and the driven shaft is slid through the transmission plate. Japanese Patent Application Laid-Open No. 2-232537 provides a cylinder in which displacement in the axial direction is converted and the axial displacement of the slide cylinder is detected by a differential transformer.

[0003]

[Problems to be solved by the device]

 As shown in FIG. 8, the above-mentioned prior art requires a plurality of transmission plates 22 arranged at a plurality of angular positions on the outer circumference of the main shaft 36 and the driven shaft 33. The diameter of 24 increases. Further, in order to improve the detection accuracy, the movement amount of the differential transformer 27 must be increased, and therefore the distance between the two points 23a and 23b of the three connecting points of the transmission plate 22 is reduced. Or, it is necessary to increase the distance between the connecting point of the two points 23a and 23b and the connecting point of the remaining one point 23c, but it is structurally difficult to reduce the distance between the two points 23a and 23b. There is only a method of increasing the distance between the connecting point of 23a and 23b and the remaining one connecting point, which causes a problem that the transmission plate 22 becomes large and the diameter of the housing 24 becomes large.

[0004]

[Means for Solving the Problems]

 The present invention has been made to solve the above-mentioned conventional problems, and a main shaft and a driven shaft are coaxially connected to each other via a torsion bar so as to be relatively rotatable, and at least one of the main shaft and the driven shaft. A slide cylinder is axially movable on one of the outer circumferences of the slide cylinder, and a displacement detector for detecting the axial displacement of the slide cylinder is provided to measure the relative rotation between the main shaft and the driven shaft. In a torque sensor equipped with a conversion mechanism for converting into a drive shaft, a sensor shaft formed on the drive shaft and the driven shaft and meshing alternately so as to approach and separate in the rotational direction by relative rotation, and the drive shaft and the driven shaft. And a flexible plate which is circumferentially connected to the end surface of the sensor shaft on the shaft side and is in contact with the end surface of the slide cylinder.

[0005]

[Action]

 With the above structure, the relative rotation between the main driving shaft and the driven shaft causes the respective sensor shafts to approach or separate from each other in the circumferential direction. When the sensor shaft approaches, the flexible plate circumferentially connected to the end surface of the sensor shaft bends according to the relative rotation angle between the main shaft and the driven shaft, and slides based on the amount of bending of the flexible plate. The cylinder is displaced in the axial direction, and the axial displacement of the slide cylinder is detected by a detector such as a differential transformer.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is a cylindrical housing having one end opened, and an end cap 2 is fixed to the opening. A driven shaft 3 (output shaft) is rotatably supported by the end cap 2 via a bearing 4, and a bearing 6 provided on the housing 1 and a needle bearing 7 provided on an inner circumference of one end of the driven shaft 3 are provided. The drive shaft 5 (input shaft) is rotatably supported by. The main driving shaft 5 and the driven shaft 3 are provided on a coaxial line, and these are connected to each other via a torsion bar 8.

A first slide cylinder 10 is axially slidably fitted on a main shaft 5 by a ball 11, and a core 12 is provided on the outer circumference of the first slide cylinder. A displacement detector 13 such as a differential transformer is fixed to the inner peripheral surface of the housing 1 so as to face the core 12.

Sensor shafts 5a, 3a are formed at the joints between the main driving shaft 5 and the driven shaft 3. As shown in FIGS. 2 to 4, the sensor shafts 5a and 3a have a concave and convex shape just like a claw coupling, and are meshed with each other with a clearance in the circumferential direction so that they can approach and separate from each other.

When the front and back surfaces of the end surfaces of the sensor shafts 5a and 3a, that is, the driving shaft 5 side is the front surface and the driven shaft 3 side is the back surface, as shown in FIG. The sensor shafts 5a and 3a are connected to each other in the circumferential direction by a flexible plate 8, and as shown in FIG. 4B, the sensor shafts 5a, A flexible plate 9 is connected to the outer peripheral portion 3a in the circumferential direction.

A second slide cylinder 14 is arranged on the back side of the sensor shafts 5a and 3a. The second slide cylinder 14 is screwed to one end of the first slide cylinder 10 across the sensor shafts 5a and 3a. Are combined and integrated with the first slide cylinder 10. Reference numeral 15 is a lock nut of the second slide cylinder 14, by which the position of the second slide cylinder 14 in the axial direction is adjusted.

Therefore, the front flexible plate 8 provided on the sensor shafts 5a and 3a is brought into contact with the end surface of the first slide cylinder 10, and the back flexible plate 9 is connected to the end surface of the second slide cylinder 14. Is abutted against.

Since the present invention has the above-described structure, as shown in FIG. 5, the sensor shafts 5a and 3a are positioned at equal intervals in the circumferential direction when the main shaft 5 and the slave shaft 3 are in the neutral position. The front and back flexible plates 8 and 9 contact the first and second slide cylinders 10 and 14 with equal flexure, and the first slide cylinder 10 is not displaced.

When the driving shaft 5 rotates rightward and rotates relative to the driven shaft 3, as shown in FIG. 6, the sensor shaft 5a on the driving shaft 5 side rotates to the right to move the driving shaft 5 on the driven shaft 3 side. Approach the sensor shaft 3a. As a result, the amount of bending of the front flexible plate 8 increases, but the back flexible plate 9 is extended because the adjacent sensor shafts 5a and 3a are separated from each other. Therefore, the amount of bending of the flexible plate 8 on the front side causes the first slide cylinder 10 to be displaced in the axial direction, and the second slide cylinder 14 to be driven by the displacement of the first slide cylinder 10 to prevent the displacement of the first slide cylinder 10. It is detected by the displacement detector 13.

When the driving shaft 5 rotates leftward and rotates relative to the driven shaft 3, the sensor shaft 5a on the driving shaft 5 side rotates leftward to rotate the driven shaft 3 as shown in FIG. It approaches the sensor shaft 3a on the side. As a result, the flexible plate 9 on the back side has a large amount of bending, but the flexible plate 8 on the front side is extended because the adjacent sensor shafts 5a and 3a are separated from each other. Therefore, the amount of bending of the flexible plate 9 on the back side causes the first slide cylinder 10 to be axially displaced through the second slide cylinder 14, and the displacement detector 13 detects the displacement of the first slide cylinder 10.

In the above embodiment, the first slide cylinder 10 and the second slide cylinder 14 are configured to be converted into axial displacement by bending of the flexible plates 8 and 9 provided on the front and back sides of the sensor shafts 5a and 3, respectively. However, the second slide cylinder 14 and the flexible plate 9 on the back side may be omitted, and the flexible plate 8 on the front side may be formed into a series of ring shapes, and the flexible portion may be tacked to the first slide cylinder 10.

[0016]

[Effect of the device]

 As described above, according to the present invention, as the conversion mechanism for converting the relative rotation of the main shaft and the driven shaft into the axial direction of the slide cylinder, the main shaft and the driven shaft are formed so as to approach each other in the rotating direction by the relative rotation. The conversion shaft is composed of the sensor shafts that are alternately meshed so as to be separated from each other, and the flexible plate that is circumferentially connected to the end surfaces of the main shaft side and the driven shaft side and that is in contact with the end surface of the slide cylinder. The structure of is simple and compact, enabling downsizing. In addition, since the flexible plate is displaced in the axial direction according to the amount of bending, it has high sensitivity, the torque detection accuracy is improved, and highly reliable torque detection can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of the present invention.

FIG. 2 is a perspective view of a sensor shaft.

FIG. 3 is a side view of the sensor shaft.

FIG. 4 is a front and back view of the sensor shaft.

FIG. 5 is an operation diagram of the sensor shaft at neutral.

FIG. 6 is an operation diagram of the sensor shaft during right rotation.

FIG. 7 is an operation diagram of the sensor shaft when turning left.

FIG. 8 is a sectional view of a conventional torque sensor.

[Explanation of symbols]

 1 Housing 3 Driven shaft 3a Sensor shaft 5 Main shaft 5a Sensor shaft 8,9 Flexible plate 10 First slide cylinder 12 Core 13 Displacement detector 14 Second slide cylinder 16 Torsion bar

Claims (1)

[Scope of utility model registration request] 1. A main shaft and a driven shaft are coaxially connected to each other via a torsion bar so as to be relatively rotatable, and a slide cylinder is provided on the outer periphery of at least one of the main shaft and the driven shaft so as to be movable in the axial direction. A torque sensor provided with a displacement detector for detecting the axial displacement of the slide cylinder and having a conversion mechanism for converting the relative rotation of the driving shaft and the driven shaft into the axial displacement of the slide cylinder. A sensor shaft formed on the shaft and meshed alternately so as to approach and separate from each other in the rotation direction by relative rotation, and a sensor shaft that is circumferentially connected to the end faces of the sensor shafts on the driving shaft side and the driven shaft side. A torque sensor comprising a flexible plate in contact with the torque sensor.