阅读说明：本技术 扭矩传感器 (Torque sensor ) 是由 远藤嵩幸 于 2019-02-08 设计创作，主要内容包括：本发明提供一种扭矩传感器,其可以高精度地检测扭矩而不依赖结构体的加工精度或应变计对结构体的配置精度。第一结构体(11)和第二结构体(12)通过多个第三结构体(13)连接。第一应变传感器(19)和第二应变传感器(20)连接于第一结构体和第二结构体之间。第一应变传感器和第二应变传感器分别具备连接于第一结构体和第二结构体之间的应变体(41)、和设置于应变体的多个传感器元件(51、52、53、54),其中多个传感器元件配置于比应变体的长边方向中央部更靠第一结构体和第二结构体中一侧的区域,该一侧的区域是应变体的扭矩方向的应变和扭矩以外的方向的应变的差较小的区域。(The invention provides a torque sensor which can detect torque with high precision without depending on the processing precision of a structural body or the arrangement precision of a strain gauge on the structural body. The first structure (11) and the second structure (12) are connected by a plurality of third structures (13). A first strain sensor (19) and a second strain sensor (20) are connected between the first structure and the second structure. The first strain sensor and the second strain sensor each include a strain body (41) connected between the first structure and the second structure, and a plurality of sensor elements (51, 52, 53, 54) provided in the strain body, wherein the plurality of sensor elements are disposed in a region on one side of the first structure and the second structure with respect to a longitudinal direction central portion of the strain body, and the region on the one side is a region in which a difference between strain in a torque direction of the strain body and strain in a direction other than the torque is small.)

1. A torque sensor is characterized by comprising:

a first structure body;

a second structural body;

a plurality of third structures connecting the first structures and the second structures; and

at least one strain sensor connected between the first structure and the second structure,

the strain sensor includes a strain body connected between the first structure body and the second structure body, and a plurality of sensor elements provided in the strain body, wherein the plurality of sensor elements are arranged in a region on one side of the first structure body and the second structure body with respect to a longitudinal center portion of the strain body, and the region on one side is a region in which a difference between a strain in a torque direction of the strain body and a strain in a direction other than the torque is small.

2. The torque sensor of claim 1,

the first structure body is annular, the second structure body is annular,

the second structure is concentrically arranged inside the first structure,

the plurality of sensor elements provided in the strain body of the strain sensor are arranged in a region closer to the second structure than a longitudinal center portion of the strain body.

3. The torque sensor according to claim 1 or 2,

the strain sensor is provided with a bridge circuit including a plurality of the sensor elements.

4. The torque sensor according to claim 2,

at least one of the strain sensors is disposed at a position symmetrical with respect to the centers of the first structure and the second structure.

Technical Field

Embodiments of the present invention relate to a torque sensor provided in a joint of a robot arm, for example.

Background

The torque sensor includes a first structure to which torque is applied, a second structure that outputs torque, and a plurality of strain portions as beams that connect the first structure and the second structure, and a plurality of strain gauges as sensor elements are disposed in the strain portions. These strain gauges form a bridge circuit (see, for example, patent documents 1, 2, and 3).

Disclosure of Invention

Problems to be solved by the invention

The bridge circuit of the torque sensor needs to be configured to output a voltage to a force in the torque direction and not to output a voltage to a force in a direction other than the torque direction. However, it is a prerequisite that the structure of the torque sensor is accurately machined and the strain gauge is accurately arranged at a predetermined position of the structure, and the machining accuracy of the structure or the arrangement accuracy of the strain gauge to the structure depends on the machining accuracy of the structure.

The present embodiment provides a torque sensor that can detect torque with high accuracy without depending on the processing accuracy of a structure or the arrangement accuracy of a strain gauge on the structure.

Means for solving the problems

Drawings

Fig. 1 is a plan view showing a torque sensor to which each embodiment is applied.

Fig. 2 is a plan view showing a portion of fig. 1 removed.

Fig. 3 is a plan view of the first embodiment with a part of fig. 2 removed.

Fig. 4 is a perspective view of fig. 3.

Fig. 5 is an enlarged plan view of a portion a shown by a broken line in fig. 3.

Fig. 6A is a plan view illustrating an operation when a force in the torque (Mz) direction is applied to the torque sensor shown in fig. 5.

Fig. 6B is a side view for explaining an operation when a force in a direction other than the torque (Fz, Mx) is applied to the torque sensor shown in fig. 5.

Fig. 7 is a perspective view showing the structure shown in fig. 5.

Fig. 8A is a cross-sectional view taken along the line VIIIA-VIIIA shown in fig. 7, and is a view illustrating a sectional moment of inertia in a direction other than the torque (Fz, Mx).

Fig. 8B is a cross-sectional view taken along line VIIIB-VIIIB shown in fig. 7, and is a view illustrating a sectional moment of inertia in a direction other than the torque (Fz, Mx).

Fig. 8C is a diagram illustrating a sectional moment of inertia of a general structure.

Fig. 8D is a diagram illustrating a sectional moment of inertia of a structure different from that of fig. 8C.

Fig. 8E is a diagram illustrating a sectional moment of inertia in the torque (Mz) direction in fig. 8A.

Fig. 8F is a diagram illustrating the sectional moment of inertia in the torque (Mz) direction in fig. 8B.

Fig. 8G is a diagram illustrating a sectional moment of inertia of a structure different from that of fig. 8C and 8D.

Fig. 8H is a diagram illustrating a positional relationship between the structural body and the strain body.

Fig. 9 is a plan view showing a torque sensor of a comparative example of the first embodiment.

Fig. 10A is a plan view illustrating an operation when a force in the torque (Mz) direction is applied to the torque sensor shown in fig. 9.

Fig. 10B is a side view for explaining an operation when a force in a direction other than the torque (Fz, Mx) is applied to the torque sensor shown in fig. 9.

Fig. 11 is a diagram showing strains when the same force is applied in the axial direction to the torque sensor of the first embodiment and the torque sensor of the comparative example.

Fig. 12 is a diagram illustrating the second embodiment, and is a plan view illustrating the first strain sensor and the second strain sensor.

Fig. 13 is a circuit diagram showing an example of a bridge circuit of the first strain sensor.

Fig. 14 is a diagram illustrating a state of a strain body when a force in a torque direction is applied to the torque sensor according to the second embodiment and when a force in a direction other than the torque direction is applied.

Fig. 15 is a diagram schematically showing a torque sensor of a comparative example of the second embodiment.

Fig. 16 is a diagram showing the third embodiment, and is an enlarged plan view showing a portion shown in B of fig. 1.

Fig. 17A is a view showing an operation of the stopper, and is a view schematically showing a part of fig. 16.

Fig. 17B is a view showing the operation of the stopper different from that of fig. 17A, and is a view schematically showing a part of fig. 16.

Fig. 18 is a diagram illustrating a relationship between the torque applied to the torque sensor and the movement of the stopper.

Fig. 19 is a diagram showing a relationship between strain and stress in the strain gauge.

Fig. 20 is a diagram showing a first modification of the third embodiment, and is an enlarged plan view showing a part thereof.

Fig. 21 is a plan view showing a second modification of the third embodiment.

The torque sensor of the embodiment includes: a first structure body; a second structural body; a plurality of third structures connecting the first structures and the second structures; and at least one strain sensor connected between the first structure and the second structure, the strain sensor including a strain body connected between the first structure and the second structure, and a plurality of sensor elements provided in the strain body, wherein the plurality of sensor elements are arranged in a region on one side of the first structure and the second structure with respect to a longitudinal direction central portion of the strain body, the region on one side being a region where a difference between a strain in a torque direction of the strain body and a strain in a direction other than the torque is small.

Effects of the invention

Embodiments of the present invention can provide a torque sensor that can detect torque with high accuracy without depending on the processing accuracy of a structure or the arrangement accuracy of a strain gauge to the structure.