CN102803913B - Torque sensor - Google Patents

Abstract

The present invention provides a torque sensor capable of detecting low torque with high precision. The torque sensor (1) of the present invention is provided with: the input shaft (4) that rotates with the drive of the drive source; the output shaft (8) that rotates with the rotation of the input shaft (4); the input shaft ( 4) The rotation drive is transmitted to the rotation transmission mechanism (6) of the output shaft (8); the deformation body (2), the deformation body (2) supports the rotation transmission mechanism (6) freely, and due to the rotation transmission through the The rotation resistance of the output shaft (8) acting on the mechanism (6) produces strain; and the strain detection mechanism (16, 17, 18, 19) for detecting the strain of the deformable body (2). With this structure, when the rotation resistance of the output shaft (8) acts on the rotation transmission mechanism (6), the strain of the deformable body (2) is detected by the strain detection mechanism (16, 17, 18, 19), then Capable of detecting torque. In addition, since the structure of the planetary gear mechanism is unnecessary, the output torque will not be amplified, and thus the rotation resistance will not increase, so low torque can be detected.

Description

torque sensor

technical field

The present invention relates to a torque sensor capable of detecting low torque with high precision.

Background technique

Conventionally, there is a torque sensor disclosed in Patent Document 1 as a torque sensor configured such that a deformable body is strained by rotational resistance acting on a gear. The torque sensor is configured to have a planetary gear mechanism interposed between the input shaft and the output shaft, and the planetary gear mechanism transmits the rotational drive of the input shaft rotated by the driving of the motor to the output shaft. This planetary gear mechanism includes: a sun gear mounted on the above-mentioned input shaft; a plurality of planetary gears meshing with the sun gear and revolving around it, and rotating on its own; teeth, and the planetary gear is guided by the inner ring side by meshing with the planetary gear. In addition, the planetary gears are pivotally supported by a bracket, and the above-mentioned output shaft is attached to the bracket. In addition, a deformation body having a strain gauge attached to a side surface thereof is mounted on the outer ring side of the internal gear, and the other end of the deformation body is fixed to the housing. With this structure, when rotational resistance acts on the output shaft, the rotational resistance acts on the internal gear in the circumferential direction of the internal gear, and a bending moment acts on the deformable body. The deformable body is strained by the bending moment, and the distortion can be detected by detecting the distortion with the distortion measuring tool.

prior art literature

Patent Document 1: Japanese Patent No. 3659748

In the above-mentioned torque sensor, the planetary gear mechanism is an essential structural element. However, due to the reduction action of the planetary gear mechanism, the output torque is amplified, and the rotational resistance acting on the output shaft also increases accordingly. Consequently, the bending moment transmitted to the deformation body via the internal gear also increases. Therefore, detectable torque is limited to a torque larger than the input torque, and low torque cannot be detected. Also, the inertia of the motor acting on the output shaft increases by the square of the deceleration coefficient. Therefore, in the torque sensor including the planetary gear mechanism, the inertia of the motor acting on the output shaft increases. Therefore, the impact torque of the output shaft increases, causing various problems such as noise and vibration.

Contents of the invention

The torque sensor of the present invention is accomplished in view of the above-mentioned problems, and is characterized in that it includes: an input shaft that rotates as the driving source is driven; an output shaft that rotates as the input shaft is driven to rotate; a rotation transmission mechanism that transmits rotational drive to an output shaft; a deformable body that rotatably supports the rotation transmission mechanism and that generates strain due to rotational resistance of the output shaft acting through the rotation transmission mechanism; and for detecting the A strain detection mechanism for the strain of a deformable body.

In addition, the above-mentioned rotation transmission mechanism is an intermediate gear, and an input gear is rotatably attached to the above-mentioned input shaft, and an output gear is also rotatably attached to the above-mentioned output shaft, so that the intermediate gear and these The input gear meshes with the output gear so that the rotational drive of the input shaft can be transmitted to the output shaft, and the intermediate gear is rotatably supported by the deformable body.

In addition, the above-mentioned rotation transmission mechanism is an intermediate sprocket, and an input sprocket is attached to the above-mentioned input shaft to rotate integrally with it, and an output sprocket is also attached to the above-mentioned output shaft to rotate integrally therewith, and the chain is wound around The rotational drive of the input shaft can be transmitted to the output shaft by these sprockets, and the intermediate sprocket is rotatably supported by the deformable body, and the intermediate sprocket is meshed with the chain.

In addition, a Roberval type cavity hole is perforated in the deformable body.

In addition, an input gear or an input sprocket is disposed in the cavity of the deformable body, and a notch communicating with the cavity is formed in the deformable body, and the intermediate gear or sprocket is disposed in the notch.

The effects of the present invention are as follows.

In the torque sensor of the present invention, the rotation transmission mechanism is rotatably supported by the deformable body. Therefore, when rotational resistance acts on the output shaft, the rotation transmission mechanism moves in a direction to press the side surface of the deformable body in accordance with the rotational resistance, and a bending moment acts on the deformable body. With this configuration, the deformable body generates a strain, and the detection mechanism detects the strain to detect torque. In addition, since the output torque is not amplified by making the structure that does not require a planetary gear mechanism, the rotation resistance does not increase, so low torque can be detected.

Description of drawings

FIG. 1 is a diagram showing the configuration of a torque sensor according to a first embodiment.

Fig. 2 is a front sectional view of the torque sensor of the first embodiment.

3 is an enlarged cross-sectional view of a main part in plan view of the torque sensor according to the first embodiment.

FIG. 4 is a diagram showing a configuration of a torque sensor according to a second embodiment.

Fig. 5 is a front sectional view of a torque sensor according to a second embodiment.

6 is an enlarged cross-sectional view of the main part of the torque sensor according to the second embodiment. FIG. 6(a) shows the meshing state of the input gear and the first intermediate gear, and FIG. 6(b) shows the meshing state of the second intermediate gear and the output gear. state.

Fig. 7 is a plan sectional view of a torque sensor according to a third embodiment.

8 is a front sectional view of a torque sensor according to a fourth embodiment.

Detailed ways

first embodiment

Next, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3 .

In FIGS. 1 and 2 , reference numeral 1 is a torque sensor, which has a deformation body (a crooked body) 2 in which a Roberval-type cavity hole 2 a is formed. The deformable body 2 is housed in a case 3 constituted by an upper cover 3a and a lower cover 3b. The upper surface of the deformable body 2 is covered with the upper cover 3a, while the lower surface of the deformable body 2 is covered with the lower cover 3b. In addition, a fixed end 2b is integrally formed at one end of the deformable body 2, and is fixed to the lower cover 3b by screws S. As shown in FIG. In addition, as shown in Figure 1, an insertion hole 2f through which a pin (not shown) can be inserted is perforated on the fixed end 2b, and an insertion hole (2f) through which the pin can be inserted is also perforated on the upper cover 3a. not shown). Then, the deformable body 2 and the upper cover 3a are fixed by inserting pins into these insertion holes 2f. In addition, the deformable body 2 is configured such that, in addition to its fixed end 2b, a predetermined gap is provided with respect to the inner surface of the above-mentioned housing 3 so as to be accommodated in the above-mentioned housing 3 so as not to be damaged due to the output shaft described in detail later. When strain is generated due to the rotation resistance of 8, it contacts the inner surface of the housing 3.

In addition, the torque sensor 1 has an input gear 5 arranged inside the cavity hole 2 a of the deformable body 2 , and the input gear 5 is attached to the input shaft 4 so as to be rotatable integrally with the input shaft 4 . The input shaft 4 is rotated by a motor (not shown) as an example of a drive source, and its both ends are rotatably held by the upper cover 3 a and the lower cover 3 b of the housing 3 via bearings 10 , 11 .

In addition, a notch 2c is formed in the deformable body 2 to communicate with the cavity hole 2a by cutting the other end thereof, and an intermediate gear 7 meshing with the input gear 5 is disposed in the notch 2c. As shown in FIG. 2, the intermediate gear 7 is configured to be mounted on the intermediate shaft 6 so as to be integrally rotatable with the intermediate shaft 6 rotatably held on the deformable body 2 via bearings 12, 13, and the The rotary drive rotates. In addition, both ends of the intermediate shaft 6 protrude from the notch 2 c of the deformable body 2 and extend to the upper cover 3 a and the lower cover 3 b of the housing 3 . Therefore, on the upper cover 3a and the lower cover 3b of the housing 3, bottomed holes 3c, 3d with a diameter larger than the diameter of the intermediate shaft 6 are perforated, so as to avoid the rotation resistance of the output shaft 8, which will be described in detail later, When the intermediate shaft 6 moves integrally with the deformable body 2 , it comes into contact with the housing 3 .

Furthermore, an output gear 9 is disposed at a position meshing with the intermediate gear 7 inside the housing 3 . The output gear 9 is configured to be mounted on the output shaft 8 so as to be integrally rotatable with the output shaft 8 rotatably held on the upper cover 3a and the lower cover 3b of the housing 3 via bearings 14, 15, and the output gear 9 is accompanied by the input shaft. 4 rotation drives while rotating. That is, in the torque sensor 1 , the input shaft 4 and the output shaft 8 are disposed off-center, and the rotational drive of the input shaft 4 is transmitted to the output shaft 8 through the intermediate gear 7 . Here, the above-mentioned input gear 5, intermediate gear 7, and output gear 9 are spur gears whose tooth directions are parallel to the rotation axis. By changing these gears to gears with different numbers of teeth, the rotational drive output to the output shaft 8 can be freely set. Decide to increase or decrease the rotational drive relative to the input shaft 4. In addition, in the torque sensor 1, the number of teeth of the input gear 5 and the output gear 9 is the same, and it is comprised so that they may not increase or decrease.

Strain gauges 16 , 17 , 18 , and 19 , which are examples of strain detection means, are attached to the deformable body 2 , and two of them are each attached to the side surfaces extending in the longitudinal direction.

Next, the action of the torque sensor 1 of the first embodiment will be described with reference to FIG. 3 . First, when the input shaft 4 rotates with the torque T1 as the motor is driven, the input gear 5 also rotates integrally therewith. Then, upon receiving the rotation of the input gear 5 , the intermediate gear 7 rotates integrally with the intermediate shaft 6 . Then, upon receiving the rotation of the intermediate gear 7 , the output gear 9 also rotates integrally with the output shaft 8 .

Here, when the rotational resistance T2 is applied to the output shaft 8 , the rotational resistance T2 is transmitted from the output gear 9 to the meshing intermediate gear 7 . Accordingly, the tooth surface of the intermediate gear 7 meshing with the output gear 9 is pressed by the output gear 9, and the pressing force F1 acts in a direction perpendicular to the tooth surface. On the other hand, the tooth surface of the intermediate gear 7 meshing with the input gear 5 is pressed by the input gear 5, and the pressing force F2 acts in a direction perpendicular to the tooth surface. Therefore, the resultant force F1+F2 of the pressing force F1 and the pressing force F2 acts on the intermediate gear 7 , and the resultant force F1+F2 also acts on the intermediate shaft 6 holding the intermediate gear 7 .

In addition, the center points of the input gear 5, the intermediate gear 7, and the output gear 9 are arranged on the line of the straight line L extending parallel to the longitudinal side of the deformable body 2, and the meshing points of the intermediate gear 7 and the output gear 9, and The meshing point of the intermediate gear 7 and the input gear 5 is also located on the line of the straight line L. As shown in FIG. That is, the acting points of the pressing force F1 and the pressing force F2 are located on the line of the straight line L. As shown in FIG. Further, the intermediate gear 7 is configured such that the angle formed by the line of action of the pressing force F1 and the straight line L and the angle formed by the line of action of the pressing force F2 and the straight line L are equal. Therefore, the resultant force F1+F2 acts in a direction perpendicular to the longitudinal side of the deformable body 2 . Therefore, the resultant force F1+F2 acts as a bending moment on the deformable body 2 strained with the fixed end 2b as a fulcrum. Torque can be detected by detecting the strain of the deformable body 2 using the strain gauges 16 , 17 , 18 , and 19 .

In the torque sensor 1 of the above-mentioned first embodiment, unlike the conventional torque sensor that has a planetary gear mechanism and has to amplify the output torque, since the output torque is not amplified, the rotation resistance does not increase. . Therefore, since the rotational resistance corresponding to the output torque without amplification acts on the deformable body 2, low torque can be detected. In addition, the resultant force F1+F2 is configured to act in a direction perpendicular to the longitudinal side of the deformable body 2 . Therefore, since the deformable body 2 can be strained even with a small bending moment, low torque can be detected with high precision. In addition, it is a gear mechanism in which only three gears are arranged in a row, and the number of parts can be reduced compared with a torque sensor equipped with a planetary gear mechanism. In addition, since the input gear 5 and the output gear 9 are arranged to be embedded in the deformable body 2, the torque sensor 1 can be downsized.

second embodiment

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 to 6 . Here, the torque sensor 21 of the second embodiment arranges the deformed body 2 of the torque sensor 1 of the first embodiment described above longitudinally, and the arrangement of various structural components is changed accordingly.

As shown in Fig. 4 and Fig. 5, the above-mentioned torque sensor 21 has a deformation body 22 formed with a Roberval type cavity hole 22a. It is configured to extend in the same direction. In addition, a fixed end 22 b is integrally formed on the upper end of the deformable body 22 so as to be fixed to the casing 23 .

In addition, the torque sensor 21 has an input shaft 24 that rotates with the drive of a motor (not shown) as an example of a drive source and extends in the same direction as the longitudinal side of the deformable body 22 . An input gear 25 is attached to the input shaft 24 so as to be rotatable integrally therewith.

A first intermediate gear 27a meshing with the input gear 25 is disposed on the upper end of the deformable body 22, and a second intermediate gear 27b is disposed on the lower end. These intermediate gears 27a, 27b are configured to be mounted on the intermediate shaft 26 so as to be integrally rotatable with the intermediate shaft 26 that passes through the upper end and the lower end of the deformable body 22 and is rotatably held on the deformable body 22 via bearings 30, 31. It rotates as the input shaft 24 is driven to rotate.

In addition, the output gear 29 meshes with the above-mentioned second intermediate gear 27b. The output gear 29 is mounted on the output shaft 28 rotatably integrally with the output shaft 28 rotatably held by the housing 23 via bearings 32 and 33 , and rotates as the input shaft 24 is driven to rotate. With this configuration, the rotational drive of the input shaft 24 is output to the output shaft 28 through the first intermediate gear 27a and the second intermediate gear 27b. Here, the input gear 25, the first intermediate gear 27a, the second intermediate gear 27b, and the output gear 29 are spur gears whose tooth direction is parallel to the rotation axis, and these gears are output to the output shaft 28 by changing these gears into gears with different numbers of teeth. The rotational drive on the input shaft 24 can be freely set to speed up or decelerate relative to the rotational drive of the input shaft 24 . In addition, in the torque sensor 21, the number of teeth of the input gear 25 and the output gear 29 is the same, and it is comprised so that it may not increase or decrease.

As shown in FIGS. 4 and 5 , strain gauges 34 , 35 , 36 , and 37 , which are examples of strain detection means, are attached to the deformable body 22 , two of which are respectively attached to the sides extending in the longitudinal direction.

Next, the operation of the torque sensor 21 of the second embodiment will be described based on FIG. 6( a ) and FIG. 6( b ). First, as shown in FIG. 6( a ), as the motor is driven, the input shaft 24 rotates forward with the torque T1, and the input gear 25 also rotates integrally therewith. Then, receiving the rotation of the input gear 25 , the first intermediate gear 27 a and the second intermediate gear 27 b rotate integrally with the intermediate shaft 26 . In addition, as shown in FIG. 6( b ), upon receiving the rotation of the second intermediate gear 27 b, the output gear 29 also rotates integrally with the output shaft 28 .

Here, as shown in FIG. 6( b ), when the rotational resistance T2 is applied to the output shaft 28 , the rotational resistance T2 is transmitted from the output gear 29 to the first intermediate gear 27 a and the second intermediate gear 27 b. At this time, the tooth surface of the second intermediate gear 27b meshing with the output gear 29 is pressed by the output gear 29, and the pressing force F1 acts in a direction perpendicular to the tooth surface. On the other hand, as shown in FIG. 6( a ), the tooth surface of the first intermediate gear 27 a meshing with the input gear 25 is pushed by the input gear 25 , and the pushing force F2 acts in a direction perpendicular to the tooth surface. Therefore, the resultant force F1+F2 of the pressing force F1 and the pressing force F2 acts on the intermediate shaft 26 holding the first intermediate gear 27a and the second intermediate gear 27b.

In addition, the center point of the input gear 25 and the first intermediate gear 27a and the center point of the second intermediate gear 27b and the output gear 29 are arranged on the line of the straight line L parallel to the width direction of the longitudinal side surface of the deformation body 22 . Therefore, the meshing point of the second intermediate gear 27b and the output gear 29 and the meshing point of the first intermediate gear 27a and the input gear 25 are also located on the line of the straight line L. That is, the acting points of the pressing force F1 and the pressing force F2 are located on the line of the straight line L. As shown in FIG. In addition, the first intermediate gear 27a and the second intermediate gear 27b are configured such that the acute angle formed by the line of action of the pressing force F1 and the straight line and the acute angle formed by the line of action of the pressing force F2 and the straight line L are equal. Therefore, the resultant force F1+F2 acts in a direction perpendicular to the longitudinal side of the deformable body 22 . Therefore, the resultant force F1+F2 acts as a bending moment on the deformable body 22 strained with the fixed end 22b as a fulcrum. Torque can be detected by detecting the strain of the deformable body 22 using the strain gauges 34 , 35 , 36 , and 37 .

third embodiment

Next, a third embodiment of the present invention will be described with reference to FIG. 7 . Here, the torque sensor 41 of the third embodiment uses sprockets 45 , 47 , and 49 instead of the input gear 5 , intermediate gear 7 , and output gear 9 used in the torque sensor 1 of the first embodiment.

In FIG. 7 , reference numeral 41 is a torque sensor, and a sprocket 45 is attached to the input shaft 44 so as to be rotatable integrally with the input shaft 44 . On the other hand, an output sprocket 49 is also attached to the output shaft 48 so as to be rotatable integrally therewith. A chain 50 is wound around these sprockets 45 and 49 , and is configured to transmit the rotational drive of the input shaft 44 to the output shaft 48 . Further, an intermediate sprocket 47 attached to the intermediate shaft 46 so as to be rotatable integrally with the intermediate shaft 46 is arranged on the outer ring side of the chain 50 , and meshes so as to guide the chain 50 .

In the torque sensor 41 of the third embodiment, as shown in FIG. 7 , when the input shaft 44 rotates with the torque T1 as the motor is driven, the input sprocket 45 also rotates integrally therewith. Receiving this rotation, the chain 50 circulates, and the output sprocket 49 is driven. At this time, the intermediate sprocket 47 disposed on the outer ring side of the chain 50 also rotates as the chain 50 circulates. Here, when rotational resistance T2 is applied to the output shaft 48 , the rotational resistance is transmitted to the intermediate sprocket 47 via the chain 50 . At this time, the pressing force F1 acts on the tooth surface of the intermediate sprocket 47 . In addition, the reaction acts on the other tooth surface of the intermediate sprocket 47 through the chain 50, and the pushing force F2 acts on the tooth surface. Therefore, the resultant force F1+F2 of the pressing forces F1 and F2 acts on the intermediate shaft 46 holding the intermediate sprocket 47 . Therefore, the resultant force F1+F2 acts on the deformable body 2 as a bending moment, and the deformable body 2 is strained with the fixed end as the fulcrum. Torque can be detected by detecting the strain of the deformable body 2 using the strain gauges 16 , 17 , 18 , and 19 .

Fourth Embodiment

In the torque sensors 1, 21, and 41 of the first, second, and third embodiments described above, the intermediate gears 7, 27a, 27b or the intermediate sprocket 47 are rotatably held by the deformable bodies 2, 22 via bearings. The upper intermediate shaft 6,26 is integrally rotatably mounted on the intermediate shaft 6,26. Here, in the torque sensor 81 of the fourth embodiment, as shown in FIG. 8 , the intermediate shaft 86 is fixed to the deformable body 2 , and accordingly, the intermediate gear 87 is rotatably attached to the intermediate shaft via bearings 88 and 89 . 86 on. Even with such a configuration, the same effects as those of the torque sensor 1 of the first embodiment can be obtained.

In addition, in the torque sensors 1 and 21 of the first and second embodiments, the input shafts 4 and 24 and the input gears 5 and 25 may be omitted, and the intermediate shaft 6 or the intermediate shaft 26 may be directly driven by a motor. In this case, the pressing force F2 shown in FIGS. 3 and 6 does not act on the intermediate shafts 6, 26, but the pressing force F1 acts as a bending moment. Therefore, since the deformable bodies 2 and 22 are strained, torque can be detected by detecting the strain.

Symbol Description

1-torque sensor, 2-deformation body, 2a-cavity hole, 2b-fixed end, 2c-notch part, 2d-upper shaft mounting part, 2e-lower shaft mounting part, 2f-pin insertion hole, 3-housing Body, 3a-upper cover, 3b-lower cover, 3c-bottomed hole, 3d-bottomed hole, 4-input shaft, 5-input gear, 6-intermediate shaft, 7-intermediate gear, 8-output shaft, 9 - output gear, 10, 11, 12, 13, 14, 15 - bearing, 16, 17, 18, 19 - strain gauge, 21 - torque sensor, 22 - deformation body, 22a - cavity hole, 22b - fixing End, 23-housing, 24-input shaft, 25-input gear, 26-intermediate shaft, 27a-first intermediate gear, 27b-second intermediate gear, 28-output shaft, 29-output gear, 30, 31, 32, 33-bearing, 34, 35, 36, 37-strain measuring piece, 41-torque sensor, 44-input shaft, 45-input sprocket, 46-intermediate shaft, 47-intermediate sprocket, 48-output shaft , 49-output sprocket, 50-chain, 81-torque sensor, 86-intermediate shaft, 87-intermediate gear, 88,89-bearing.

Claims (4)

1. a torque sensor, is characterized in that, possesses:

The input gear of following the rotation of input shaft and rotate;

Transmit the rotation of this input gear, and to be positioned at output shaft on the axis different from the above-mentioned input shaft output gear as turning axle;

Engage and transmit one or more neutral gears of rotation with these input gears and output gear;

Deformable body, this deformable body wears cavity bore and is Luo Baiwaer type on single part, and supports the turning axle of above-mentioned neutral gear; And

Stick on the side of this deformable body, the strain detecting mechanism of the strain producing for detection of deformable body.

2. a torque sensor, is characterized in that, possesses:

The input gear of following the rotation of input shaft and rotate;

Transmit the output gear of the output shaft side of the rotation of this input gear;

Engage and transmit one or more neutral gears of rotation with these input gears and output gear;

Deformable body, this deformable body wears cavity bore and is Luo Baiwaer type on single part, and only supports the turning axle of above-mentioned neutral gear; And

Stick on the side of this deformable body, the strain detecting mechanism of the strain producing for detection of deformable body.

3. torque sensor according to claim 1 and 2, is characterized in that,

On above-mentioned deformable body, form the notch being communicated with cavity bore, in this notch, configure above-mentioned neutral gear.

4. torque sensor according to claim 1 and 2, is characterized in that,

Above-mentioned neutral gear is made up of the first neutral gear and the second neutral gear, on the other hand, above-mentioned deformable body is longitudinally being configured to along the direction extension identical with input shaft and output shaft, the mode that turning axle connects this deformable body with its top and bottom is supported on this deformable body, the first neutral gear be installed in the upper end of this turning axle and engaged with above-mentioned input gear, and the second neutral gear be installed in the lower end of this turning axle and engaged with above-mentioned output gear.