CN118257837A - Eccentric swing type speed reducer - Google Patents

Abstract

An object of the present invention is to provide an eccentric swing type speed reducer capable of detecting torque or moment by reducing noise. An eccentric oscillating speed reducer (100) of an embodiment has a housing (6) provided with an internal gear (16), wherein a1 st strain sensor (71) is mounted on a1 st position (P1) of the housing (6), and a2 nd strain sensor (72) is mounted on a2 nd position (P2) of the housing (6) that is different from the 1 st position (P1).

Description

Eccentric swing type speed reducer

The present application claims priority based on japanese patent application No. 2022-208635 filed on day 26 of 12 of 2022. The entire contents of this japanese application are incorporated by reference into the present specification.

Technical Field

The invention relates to an eccentric swing type speed reducer.

Background

A reduction gear is known that reduces the rotation input to an input shaft and outputs the reduced rotation. For example, patent document 1 discloses a reduction gear including: a speed reducing unit for reducing an output rotation speed relative to an input rotation speed between the input rotation shaft and the output rotation shaft; and a housing accommodating the speed reducing portion. In order to reliably measure the load torque during operation, the speed reduction device is provided with: the buffer mechanism is arranged between the outer shell and the inner shell of the shell; and a measuring mechanism for measuring the displacement generated in the housing by the buffer mechanism.

Patent document 1: japanese patent laid-open No. 2018-179043

The present inventors have obtained the following new knowledge for an eccentric oscillating type speed reducer. In order to stably use the speed reducer, it is possible to consider measuring the torque or moment of the speed reducer during operation. However, if a strain gauge is attached to the speed reducer to detect torque or moment, the torque or moment may not be detected due to noise picked up by the influence of engagement or the influence of an outer pin. The reduction gear described in patent document 1 has room for improvement from the standpoint of reducing noise and detecting torque or moment.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object thereof is to provide an eccentric oscillating type speed reducer capable of detecting torque or moment by reducing noise.

In order to solve the above-described problems, an eccentric oscillating type speed reducer according to an embodiment of the present invention includes a housing provided with an internal gear, wherein a 1 st strain sensor is mounted at a 1 st position of the housing, and a 2 nd strain sensor is mounted at a 2 nd position of the housing different from the 1 st position.

Any combination of the above components or a manner in which the components or expressions of the present invention are mutually replaced between methods, systems, and the like is also effective as an embodiment of the present invention.

According to the present invention, an eccentric swing type speed reducer capable of detecting torque or moment by reducing noise is provided.

Drawings

Fig. 1 is a cross-sectional view schematically showing an example of an eccentric oscillating speed reducer according to an embodiment.

Fig. 2 is a block diagram schematically showing an example of the information processing unit of fig. 1.

Fig. 3 is a block diagram schematically showing another example of the information processing unit.

In the figure: p1-1 st position, P2-2 nd position, 6-shell, 14, 15-external gear, 16-internal gear, 26, 27-main bearing, 37-output flange, 71-1 st strain sensor, 72-2 nd strain sensor, 100-eccentric swing type speed reducer.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiment and the modification, the same or equivalent constituent elements and components are denoted by the same reference numerals, and overlapping description thereof is omitted as appropriate. In the drawings, the dimensions of the display elements are appropriately enlarged or reduced for the sake of understanding. In the drawings, parts of components not essential to the description of the embodiments are omitted.

The terms including the numbers 1 and 2 are used to describe various components, but the terms are only used for the purpose of distinguishing one component from other components, and the components are not limited by the terms.

Embodiment(s)

The overall structure of the eccentric oscillating type speed reducer 100 (hereinafter, sometimes simply referred to as "speed reducer 100") according to the embodiment will be described with reference to fig. 1, 2, and 3. Fig. 1 is a side sectional view schematically showing a speed reducer 100. The speed reducer 100 according to the embodiment is an eccentric oscillating type speed reducer that oscillates an external gear meshing with an internal gear, rotates one of the internal gear and the external gear, and outputs the rotation component generated from an output member to a driven member.

In the example of fig. 1, the speed reducer 100 is a so-called distributed eccentric oscillating speed reducer in which a crankshaft is disposed at a position offset from the axial center of an internal gear. The speed reducer 100 mainly includes: a crankshaft 20; external gears 14, 15; an internal gear 16; wheel frames 35, 36; a housing 6; main bearings 26, 27; crank bearings 39, 40; and an input gear 56.

Hereinafter, the direction along the center axis La of the internal gear 16 will be referred to as the "axial direction", and the circumferential direction and the radial direction of a circle centered on the center axis La will be referred to as the "circumferential direction" and the "radial direction", respectively. For convenience, one side in the axial direction (right side in the drawing) is referred to as an input side, and the other side (left side in the drawing) is referred to as an opposite input side.

The 1 st strain sensor 71 is mounted at a 1 st position P1 of the housing 6, and the 2 nd strain sensor 72 is mounted at a2 nd position P2 of the housing 6 different from the 1 st position P1. The 1 st strain sensor 71 and the 2 nd strain sensor 72 may be the same type of sensor or different types of sensors. The 1 st strain sensor 71 and the 2 nd strain sensor 72 supply signals S1 and S2 corresponding to the magnitude of the strain of the housing 6 at the mounting position to the information processing section 73. The information processing unit 73 calculates and outputs torque applied to the speed reducer 100 and torque transmitted to the speed reducer 100 based on the signals S1 and S2. The arrangement of the 1 st strain sensor 71 and the 2 nd strain sensor 72 will be described later.

For example, the calculated moments can be used for life prediction of the main bearings 26, 27. The calculated torque can be used for life prediction of the tooth surfaces of the crank bearings 39, 40 or the external gears 14, 15. That is, these can be used for life prediction of the speed reducer 100. The correlation between the moment and the life of main bearings 26, 27 may be obtained in advance by a simulation test or the like, and the life thereof may be predicted (estimated) using the correlation and the calculated moment. Further, the correlation between the torque and the life of the crank bearings 39, 40 or the life of the tooth surfaces of the external gears 14, 15 may be obtained in advance by a simulation test or the like, and the life of these may be predicted (estimated) using the correlation and the calculated torque. These lifetime predictions (estimations) can be realized by an information processing means (not shown) including a CPU or the like.

The structure of each portion of the speed reducer 100 will be described. The carriers 35 and 36 include a1 st carrier 35 disposed on the side opposite to the input side of the external gears 14 and 15 and a2 nd carrier 36 disposed on the side of the input side of the external gears 14 and 15. The casing 6 has a cylindrical shape surrounding the speed reducer 100, and an internal gear 16 is provided on an inner peripheral surface thereof. The housing 6 supports the outer peripheral sides of the main bearings 26, 27. The housing 6 includes a2 nd outer peripheral portion 62, a1 st outer peripheral portion 61, and a3 rd outer peripheral portion 63 in this order from the input opposite side toward the input side.

The main bearings 26 and 27 include a1 st main bearing 26 disposed on the side opposite to the input side of the external gears 14 and 15 and a2 nd main bearing 27 disposed on the side of the input side of the external gears 14 and 15. Main bearings 26, 27 support housing 6. The main bearings 26, 27 in this example are angular ball bearings, but are not limited thereto. The wheel carriers 35 and 36 are rotatably supported by the housing 6 via main bearings 26 and 27.

The crankshaft bearings 39 and 40 are disposed between the crankshaft 20 and the carriers 35 and 36, and rotatably support the crankshaft 20 with respect to the carriers 35 and 36. The crank bearings 39, 40 in this example are tapered roller bearings, but are not limited thereto.

Three crankshafts 20 are disposed at positions offset from a center axis La of the internal gear 16. Reference sign Lb denotes a rotation center line of the crankshaft 20. The three crankshafts 20 are arranged at equal intervals in the circumferential direction. In fig. 1, only one crankshaft 20 is shown. In order to oscillate the external gears 14, 15, the crankshaft 20 has a plurality of eccentric portions 24, 25 eccentric with respect to the rotation center line Lb of the crankshaft 20. The crankshaft 20 in this example has two eccentric portions 24, 25 whose eccentric phases are offset from each other by 180 °.

The crankshaft 20 is supported by the 1 st wheel carrier 35 and the 2 nd wheel carrier 36 via crankshaft bearings 39 and 40. The crank bearing 39 on the opposite side of the external gears 14, 15 is provided between the crankshaft 20 and the 1 st carrier 35 on the opposite side of the external gears. The input-side crankshaft bearing 40 is provided between the crankshaft 20 and the 2 nd carrier 36 in the input-side portions of the external gears 14, 15.

An input gear 56 is provided at an input side end of each crankshaft 20. In fig. 1, only one input gear 56 is shown. The input gear 56 is meshed with a motor pinion 55 of the motor shaft 54, and rotation of the motor shaft 54 is input to the input gear 56.

The external gears 14 and 15 are provided in correspondence with the eccentric portions 24 and 25 via the eccentric roller 19, and have three inner pin holes 41 and 42 and three swing holes 45 and 46, respectively, which are arranged at equal intervals in the circumferential direction. An inner pin 48 is inserted into each of the inner pin holes 41 and 42. Eccentric portions 24 and 25 of the crankshaft 20 are inserted into the respective swing holes 45 and 46, and a plurality of eccentric rollers 19 are interposed between the swing holes 45 and 46 and the eccentric portions 24 and 25. The external teeth formed on the outer circumferences of the external gears 14, 15 are moved while being in contact with the internal gear 16, whereby the external gears 14, 15 can be oscillated.

The internal gear 16 has: an internal gear body 18 integrated with an inner peripheral portion of the housing 6; and an outer pin 17 disposed in a pin groove formed in the internal gear body 18. The outer pin 17 constitutes the inner teeth of the inner gear 16 and meshes with the outer teeth of the outer gears 14, 15. The number of outer pins 17 is slightly larger than the number of outer teeth of the outer gears 14, 15 (in this example, only 1 more).

The inner pin 48 extends axially from the 1 st wheel frame 35 and is fixed to the 2 nd wheel frame 36 by a bolt B1. The inner pins 48 are inserted into the inner pin holes 41 and 42 with gaps between them and the inner pin holes 41 and 42 of the external gears 14 and 15.

One of the 1 st carrier 35 and the housing 6 serves as an output member for outputting rotational power to a driven member (not shown), and the other is a fixed member fixed to an external member (not shown) for supporting the speed reducer 100.

Next, a deceleration operation of the speed reducer 100 will be described. The rotational power is distributed to the input gears 56 via the motor pinion gears 55 of the motor shaft 54, and the three input gears 56 rotate in the same phase. When the three input gears 56 rotate, the eccentric portions 24 and 25 of the crankshaft 20 rotate about the rotation center line passing through the crankshaft 20, and the eccentric portions 24 and 25 oscillate the external gears 14 and 15. When the external gears 14 and 15 oscillate, the meshing positions of the external gears 14 and 15 and the external pins 17 of the internal gear 16 are sequentially shifted. As a result, one of the external gears 14, 15 and the internal gear 16 rotates by an amount corresponding to the difference between the number of teeth of the external gears 14, 15 and the number of external pins 17 of the internal gear 16 per rotation of the crankshaft 20. In the embodiment, the external gears 14 and 15 rotate, and the 1 st carrier 35 which rotates in synchronization with the rotation components of the external gears 14 and 15 outputs the decelerated rotation. As the 1 st wheel frame 35 rotates, the driven member coupled to the 1 st wheel frame 35 is rotationally driven.

The 1 st strain sensor 71 and the 2 nd strain sensor 72 will be described. As described above, the 1 st strain sensor 71 is mounted at the 1 st position P1 of the housing 6, and the 2 nd strain sensor 72 is mounted at the 2 nd position P2 of the housing 6 different from the 1 st position P1. The 1 st strain sensor 71 and the 2 nd strain sensor 72 detect the strain of the housing 6 at the mounted positions P1, P2, and supply signals S1, S2 corresponding to the magnitudes of the strain to the information processing unit 73.

The 1 st strain sensor 71 and the 2 nd strain sensor 72 may be the same kind of sensor. Here, the same type of strain sensor means that when the same strain is detected, a signal having substantially the same level or a level proportional to the level can be supplied as a detection result, and the manufacturer, model, or the like may be different. The 1 st strain sensor 71 and the 2 nd strain sensor 72 may be strain gauges capable of detecting, as an electrical signal, a deformation amount (i.e., strain) of an object to be detected that deforms slightly in an expanding manner based on stress.

The information processing unit 73 calculates and outputs a torque (hereinafter, simply referred to as "torque") applied to the speed reducer 100 and a torque (hereinafter, simply referred to as "torque") transmitted to the speed reducer 100 based on the signals S1 and S2.

The signals S1 and S2 are ac signals that become positive and negative with the passage of time, and include a torque-based component M, a torque-based component T, and an unnecessary noise component (i.e., component N) other than the torque component and the torque component. The information processing unit 73 calculates and outputs the component M and the component T from the signals S1 and S2.

The information processing unit 73 will be described. Fig. 2 is a block diagram schematically showing an example of the information processing unit 73. By adjusting the arrangement of the 1 st strain sensor 71 and the 2 nd strain sensor 72, the component N can be contained in the signals S1 and S2 substantially uniformly, the component T can be contained in the signal S1 in a large amount and the signal S2 in a small amount, and the component M can be contained in the signal S2 and the signal S1 in a large amount. At this time, simultaneous equations of the signals S1, S2, the component M, the component T, and the component N are established. By obtaining the coefficients A1, B1, A2, B2 of the equation in advance and inputting the signals S1, S2 into the equation, the component M and the component T whose influence of the component N is reduced can be calculated. For example, the coefficients A1, B1, A2, and B2 of the equation can be obtained by acquiring signals S1 and S2 in a state where a predetermined torque is applied to the speed reducer 100 and the predetermined torque is transmitted. The information processing unit 73 includes a CPU or a memory for calculating the component M and the component T from the signals S1 and S2.

Another example of the information processing unit 73 will be described. Fig. 3 is a block diagram schematically showing another example of the information processing unit 73. In another example, the information processing unit 73 can use the learning model E to calculate (calculate) the component M and the component T from the signals S1 and S2. The learning model E is an AI model generated by machine learning based on the reference signals S1 and S2 acquired in advance and actual measurement data of the moment and torque corresponding to the reference signals. By using the learning model E, the data processing can be speeded up, and high accuracy can be easily obtained. The learning model E provides the component M and the component T corresponding thereto based on the input signals S1 and S2. The learning model E may be generated using a well-known machine learning method. The learning model E may be generated from actual measurement data of torque and moment collected from other speed reducers of the same kind in the past, or may be generated from actual measurement data of torque and moment collected from the target speed reducer 100.

The arrangement of the 1 st strain sensor 71 and the 2 nd strain sensor 72 will be described with reference to fig. 1. As described above, the housing 6 includes the 2 nd outer peripheral portion 62, the 1 st outer peripheral portion 61, and the 3 rd outer peripheral portion 63 in this order from the input opposite side toward the input side. The radial thickness of the portion of the housing 6 corresponding to the 1 st outer peripheral portion 61 is thicker than the radial thickness of the portions of the housing 6 corresponding to the 2 nd outer peripheral portion 62 and the 3 rd outer peripheral portion 63.

If the 1 st strain sensor 71 and the 2 nd strain sensor 72 are mounted separately from each other, the difference between the signals S1 and S2 becomes larger, and a signal in which the degree of influence of each of the moment and the torque is changed depending on the position can be obtained. Therefore, in the embodiment, the axial positions of the 1 st position P1 and the 2 nd position P2 are different. At this time, since the axial positions are different, the ease of reception of the torque and the ease of reception of the torque of each sensor are changed, and therefore the ease of reception of the torque and the ease of reception of the torque with respect to the strain detected by each sensor are different, and the magnitudes of the component M and the component T included in the signals S1 and S2 are different, respectively. As a result, the accuracy of the components M and T can be improved by measuring the relationship between the signals S1 and S2 and the components M and T in advance. In the embodiment, the 1 st position P1 is provided on the 1 st outer peripheral portion 61, and the 2 nd position P2 is provided on the 2 nd outer peripheral portion 62. In the embodiment, the 1 st position P1 and the 2 nd position P2 are positions having different diameters on the housing 6, but the present invention is not limited thereto, and the 1 st position P1 and the 2 nd position P2 may be positions having the same diameters on the housing 6.

When the 1 st strain sensor 71 and the 2 nd strain sensor 72 are respectively mounted at positions having different rigidities, a signal that changes the degree of influence of the moment depending on the rigidity can be obtained. Therefore, in the embodiment, the 1 st position P1 and the 2 nd position P2 are positions on the housing 6 where the radial thicknesses are different from each other. At this time, the radial thickness of the housing 6 at the 1 st position P1 is thicker than the radial thickness of the housing 6 at the 2 nd position P2 and thus the rigidity is higher, and therefore the 1 st strain sensor 71 can output the signal S1 hardly affected by the moment.

As an example, the 1 st position P1 may be arranged to overlap with the meshing positions of the internal gear 16 and the external gears 14 and 15 in the radial direction, and the 2 nd position P2 may be arranged to overlap with the main bearings 26 and 27 of the support housing 6 in the radial direction. In fig. 1, an example of the range of the meshing positions of the internal gear 16 and the external gears 14 and 15 is indicated by a symbol K, and an example of the range of the main bearings 26 and 27 is indicated by symbols J1 and J2. Position 1 overlaps in the radial direction with range K of the engagement position, and position 2 overlaps in the radial direction with range J1 of main bearing 26, position 2. The 1 st strain sensor 71 of the 1 st position P1 is mounted at a position overlapping with the meshing position, and therefore the strain at the 1 st position P1 is greatly affected by the meshing of the internal gear 16 with the external gears 14, 15. The 1 st strain sensor 71 can output a signal S1 containing a relatively large amount of the component T based on the transmission torque, which is the strain based on the influence of the meshing of the internal gear 16 with the external gears 14, 15.

Further, with respect to main bearings 26, 27, since torque from the driven member is applied to output flange 37, strain at 2 nd position P2 overlapping main bearings 26, 27 in the radial direction includes strain based on both the influence of torque and the influence of transmission torque. Therefore, the 2 nd strain sensor 72 can output the signal S2 including the component M based on the moment and the component T based on the transmitted moment in a large amount.

In the embodiment, the 1 st carrier 35 functions as an output flange 37 for transmitting the output rotation of the speed reducer 100 to the driven member, and the 2 nd position P2 overlaps the 1 st main bearing 26 supporting the output flange 37 in the radial direction. At this time, since the target member is provided on the opposite side to the output flange 37 side, it is difficult to affect the mountability.

The phases of the strain based on the torque and the influence of the moment at the 1 st position P1 and the 2 nd position P2 preferably coincide. Therefore, in the embodiment, the circumferential positions of the 1 st position P1 and the 2 nd position P2 overlap each other. That is, the 1 st position P1 and the 2 nd position P2 are located at the same phase in the circumferential direction, and in the example of fig. 1, are located at the same time point on the clock position centered on the central axis La when viewed from the input side in the axial direction. In this case, since the phases of the strain due to the influence of the torque and the moment are easily matched, the calculation of the component M and the component T becomes easy, and the calculation accuracy can be improved. In addition, when the mounting positions overlap in the circumferential direction, the 1 st strain sensor 71 and the 2 nd strain sensor 72 can be mounted from one direction of the speed reducer 100, and thus the operability is improved.

Next, the features of the eccentric oscillating type speed reducer 100 having the above-described configuration will be described. The eccentric oscillating type speed reducer 100 has a housing 6 provided with an internal gear 16, wherein a1 st strain sensor 71 is mounted at a1 st position P1 of the housing 6, and a2 nd strain sensor 72 is mounted at a2 nd position P2 of the housing 6 different from the 1 st position P1.

According to this configuration, it is possible to provide an eccentric oscillation type speed reducer capable of detecting a torque and a torque reduced in the influence of noise from signals of the 1 st strain sensor 71 and the 2 nd strain sensor 72 provided at different positions from each other.

The above is a description of the embodiments.

The present invention has been described above with reference to the embodiments. These embodiments are examples, and it will be understood by those skilled in the art that various modifications and changes can be made within the technical scope of the present invention, and that these modifications and changes are also within the technical scope of the present invention. Accordingly, the descriptions and drawings in this specification should not be considered as limiting, but rather as illustrative.

(Modification)

The following describes modifications. In the drawings and description of the modification, the same or equivalent constituent elements and components as those of the embodiment are denoted by the same reference numerals. The description repeated with the embodiment is omitted appropriately, and the description is focused on the structure different from the embodiment.

In the description of the embodiment, the example of the so-called distributed eccentric oscillating type speed reducer in which the speed reducer 100 is provided with the plurality of crankshafts 20 at positions offset from the axial center of the internal gear 16 is shown, but the present invention is not limited to this, and various speed reducing mechanisms may be employed. For example, the speed reducer may be a so-called center crank type eccentric oscillating speed reducer in which a crankshaft is disposed at an axial center position of an internal gear.

In the description of the embodiment, an example is shown in which the speed reducer 100 includes two external gears 14, but the present invention is not limited to this. The speed reducer may be provided with one or more external gears.

These modifications also have the same operational effects as those of the embodiment.

Any combination of the above embodiments and modifications is also useful as an embodiment of the present invention. The new embodiment produced by the combination has the effects of the combined embodiment and the modification.

Claims (6)

1. An eccentric swing type speed reducer having a housing provided with an internal gear thereon, characterized in that,

A 1 st strain sensor is mounted at a 1 st position of the housing, and a2 nd strain sensor is mounted at a2 nd position of the housing different from the 1 st position.

2. The eccentric swing type speed reducer according to claim 1,

The axial positions of the 1 st position and the 2 nd position are different from each other.

3. The eccentric swing type speed reducer according to claim 1,

The 1 st position and the 2 nd position are positions on the housing where radial thicknesses are different from each other.

4. The eccentric swing type speed reducer according to claim 1,

An external gear meshed with the internal gear is also provided,

The 1 st position overlaps with the meshing positions of the internal gear and the external gear in the radial direction,

The 2 nd position overlaps in the radial direction with a main bearing supporting the housing.

5. The eccentric swing type speed reducer according to claim 4,

The device is also provided with an output flange,

The 2 nd position overlaps in radial direction with a main bearing supporting the output flange.

6. The eccentric swing type speed reducer according to claim 1,

The circumferential positions of the 1 st position and the 2 nd position overlap each other.