Differential and Suspension Mechanisms

Abstract

To provide a small-sized differential mechanism that suppresses vibration due to backlash of gears and has high rigidity.SOLUTION: A differential mechanism includes: a first stationary plate 19; a first wave gear device 1 including a first circular spline 211, a first flex spline 221 and a first wave generator 231, in which the first circular spline 211 is fixed to the first stationary plate 19; a first rotation shaft 12 connected to the first flex spline 221; a second wave gear device 2 including a second circular spline 212, a second flex spline 222 and a second wave generator 232, in which the second flex spline 222 is fixed to the first stationary plate 19; a second rotation shaft 13 connected to the second circular spline 212; and a third rotation shaft 14 for connecting the first wave generator 231 to the second wave generator 232.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a differential mechanism and a suspension mechanism. [Background technology]

[0002] When a vehicle such as a probe travels on the surface of the moon or a planet, or in an uneven environment such as a desert, it is important that all of the vehicle's running mechanisms remain in contact with the ground in order to travel on soft surfaces and overcome rocks and uneven terrain. For example, a structure has been proposed in which a differential mechanism using a differential gear is added to a traveling mechanism with rocker crawlers (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-302830 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned structure, three bevel gears are used as the differential gear. In this case, backlash in the bevel gears can cause the vehicle to pitch forward or the rear to sink, or vibrate forward and backward as the vehicle moves, if the center of gravity of the vehicle differs from the center of the vehicle.

[0005] In order to reduce the effects of pitching, it is essential to reduce the size of the teeth of the gears used in the differential mechanism or to increase the pitch circle diameter of the gears. However, there are problems in that the strength and rigidity of the differential mechanism decreases when the gears are made smaller, and the overall size of the differential mechanism increases when the gear diameter is increased. Furthermore, a differential mechanism using bevel gears requires at least three rotating shafts due to its structure. This results in a large differential mechanism, which is not able to meet the demand for smaller vehicles.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a differential mechanism that suppresses vibration caused by gear backlash, has high rigidity, and is compact. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention proposes the following means. The differential mechanism according to the present invention includes a first strain wave gear device comprising a fixed plate, a first circular spline, a first flexspline, and a first wave generator, with the first circular spline fixed to the fixed plate, a first rotating shaft connected to the first flexspline, a second strain wave gear device comprising a second circular spline, a second flexspline, and a second wave generator, with the second flexspline fixed to the fixed plate, a second rotating shaft connected to the second circular spline, and a third rotating shaft connecting the first wave generator and the second wave generator.

[0008] According to this invention, first, the rotation input to the first rotating shaft is transmitted to the first flexspline. The rotation input to the first flexspline is accelerated by the first wave gear device and output as rotation in the opposite direction to the first wave generator. The rotation of the first wave generator is transmitted to the second wave generator connected by the third rotating shaft. The rotation of the second wave generator is decelerated by the second wave gear device and output as rotation in the same direction to the second circular spline. The rotation of the second circular spline is transmitted to the second rotating shaft. The rotation input to the second rotating shaft is transmitted to the first rotating shaft by reversing the above-mentioned process.

[0009] In this way, while the first wave generator and the second wave generator connected by the third rotating shaft rotate in the same direction, the above-mentioned configuration causes the first wave gear device to output rotation in the opposite direction to the rotation input from the first rotating shaft to the third rotating shaft, and the second wave gear device to output rotation in the same direction to the rotation input from the third rotating shaft to the second rotating shaft.

[0010] By adopting such a structure, the differential mechanism can be made smaller and more rigid while suppressing vibration due to backlash. The above-described configuration can be suitably used in the field of industrial robots and the like, for example, when a differential mechanism with reduced vibration is required.

[0011] Furthermore, the suspension mechanism of the present invention comprises a first rocker arm and a second rocker arm having a plurality of traveling mechanisms at both longitudinal ends thereof, and the differential mechanism, wherein the longitudinal center of the first rocker arm is connected to the first rotating shaft perpendicular to the longitudinal direction, and the longitudinal center of the second rocker arm is connected to the second rotating shaft perpendicular to the longitudinal direction, and the first rocker arm and the second rocker arm passively rotate in opposite directions about the first rotating shaft or the second rotating shaft.

[0012] According to this invention, the first rocker arm and the second rocker arm, each having a plurality of traveling mechanisms at both ends in the longitudinal direction, passively rotate in opposite directions about a rotation axis that is perpendicular to the longitudinal direction. Here, let us assume that a vehicle equipped with such a suspension mechanism is moving on flat ground by the running mechanism with the longitudinal direction of the first rocker arm and the second rocker arm as the travel direction. For example, when the running mechanism on the travel direction side of the first rocker arm runs over a step, the first rotating shaft to which the rocker arm is connected rotates with a change in the angle of the rocker arm. Accordingly, the second rotating shaft rotates in the opposite direction to the first rotating shaft. This causes the second rocker arm to rotate in a direction perpendicular to the longitudinal direction.

[0013] When the rotation of the second rocker arm is centered on the travel mechanism on the vehicle side of the second rocker arm, the rotation of the second rocker arm acts to press the travel mechanism on the opposite side of the second rocker arm to the ground. As a result, all travel mechanisms other than the one that has climbed up onto the step can remain in contact with the ground. This allows the vehicle to have better traversal capabilities on roads with poor surface conditions.

[0014] As described above, the differential mechanism according to the present invention can be made small and highly rigid, and can also suppress vibration. Therefore, pitching and vibration of the vehicle body can be suppressed, stable running can be achieved, and a small vehicle can be realized. The above-mentioned configuration can be suitably used for a vehicle that travels on rough terrain such as the moon or the desert, etc. Specifically, the suspension mechanism can be suitably used for a lunar exploration vehicle, a material transport vehicle in the desert, etc. Effect of the Invention

[0015] According to the present invention, it is possible to provide a differential mechanism that suppresses vibration caused by backlash of gears, has increased rigidity, and is compact. [Brief description of the drawings]

[0016] [Figure 1] 1 is an overall view of a differential mechanism according to the present invention; [Diagram 2] FIG. 2 is a perspective view showing the basic structure of a strain wave gear device used in the present invention. [Diagram 3] FIG. 2 is a perspective view of a structure including a first strain wave gear device in the differential mechanism shown in FIG. 1. [Figure 4] FIG. 2 is a perspective view of a structure including a second strain wave gear device in the differential mechanism shown in FIG. 1. [Diagram 5] 1 is a perspective view showing an example in which a differential mechanism according to the present invention is applied to a vehicle. [Figure 6] 6 is a perspective view showing an example in which a vehicle body is loaded on the vehicle shown in FIG. 5. FIG. [Figure 7]One of the running mechanisms equipped on the vehicle shown in FIG. 6 is an example of a vehicle that can climb over rocks. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a differential mechanism 24 according to an embodiment of the present invention will be described with reference to the drawings. 1 shows an embodiment of a differential mechanism 24 according to the present invention. The differential mechanism 24 includes a first wave gear device 1, a second wave gear device 2, a first fixed portion 3, a second fixed portion 4, a third fixed portion 5, a fourth fixed portion 6, a fifth fixed portion 7, a first flange 8, a second flange 9, a third flange 10, a fourth flange 11, a first rotating shaft 12, a second rotating shaft 13, a third rotating shaft 14, a first fixed disk 15, a second fixed disk 16, a first bearing housing 17, a second bearing housing 18, a first fixed plate 19, and a second fixed plate 20.

[0018] 2, the first wave gear device 1 and the second wave gear device 2 are so-called Harmonic Drives (registered trademark) that each include a circular spline 21, a flexspline 22, and a wave generator 23. A typical wave gear device has a structure that reduces the speed of rotation input from the wave generator 23 and outputs it from the flexspline 22.

[0019] Furthermore, when the circular spline 21 is used as a reference, the flexspline 22 and the wave generator 23 rotate in opposite directions. In other words, when the flexspline 22 is used as a reference, the circular spline 21 and the wave generator 23 rotate in the same direction.

[0020] The first wave gear device 1 and the second wave gear device 2 of the differential mechanism 24 according to the present invention are identical wave gear devices, but have different fixing methods for the first fixed plate 19 (details will be described later). Hereinafter, the above-mentioned components of the first strain wave gearing 1 may be particularly referred to as the first circular spline 211, the first flexspline 221, and the first wave generator 231. Moreover, the above-mentioned components of the second strain wave gearing 2 may be particularly referred to as the second circular spline 212, the second flexspline 222, and the second wave generator 232.

[0021] The first fixed plate 19 is a member having a U-shaped cross section, and each component part of the differential mechanism 24 is fixed thereon. Alternatively, when the differential mechanism 24 is assembled into an external structure, the first fixed plate 19 is connected to the external structure. In this manner, the first fixed plate 19 serves as a so-called framework part of the differential mechanism 24.

[0022] The first fixed portion 3 fixes the first circular spline 211 of the first wave gearing 1 to the first fixed plate 19. This allows the first flexspline 221 and the first wave generator 231 of the first wave gearing 1 to rotate. 3, in order to ensure the above-mentioned structure, the first fixing portion 3 has a U-shaped cross section consisting of a first side surface 3a, a second side surface 3b, and a bottom surface 3c. The first side surface 3a and the second side surface 3b are provided with bolt holes (not shown) for fixing to the first fixing plate 19. The bottom surface 3c is provided with a bolt hole (not shown) for bolting the first circular spline 211, and a through hole for enabling the third rotating shaft 14 (described later) to be connected to the first wave generator 231.

[0023] The second fixing portion 4 connects the first flexspline 221 and the first flange 8. For example, a bolt is preferably used to fix the second fixing portion 4 and the first flexspline 221. For connection between the second fixing portion 4 and the first flange 8, a bolt is preferably used to fix the second fixing portion 4 and the first flange 8. As shown in FIG. 3, in order to ensure the above-mentioned structure, the second fixing portion 4 is cylindrical with an outer diameter equal to the outer diameter of the first flexspline 221, and has a bolt hole (not shown) at one end in the axial direction of the cylinder for fixing to the first flexspline 221, and a bolt hole (not shown) at the other end for fixing to the first flange 8.

[0024] The third fixed part 5 fixes the second flexspline 222 to the first fixed plate 19. This allows the second circular spline 212 and the second wave generator 232 to rotate in the second wave gear device 2. As shown in FIG. 4, in order to ensure the above-mentioned functions, the third fixed part 5 has an I-shaped cross section made up of an upper surface 5a, a lower surface 5b, and a central portion 5c. The upper surface 5a and the lower surface 5b are provided with bolt holes (not shown) for fixing to the first fixed plate 19. In addition, the central portion 5c is provided with a bolt hole (not shown) for fixing the second flexspline 222.

[0025] The fourth fixing portion 6 connects the second circular spline 212 and the third flange 10. The fourth fixing portion 6 and the second circular spline 212 are preferably fixed to each other by, for example, a bolt. The fourth fixing portion 6 and the third flange 10 are preferably connected to each other by a bolt. As shown in FIG. 4, the fourth fixed portion 6 has a first surface 6a, a second surface 6b, and a connecting portion 6c to ensure the above-mentioned structure. The first surface 6a is flat and has a bolt hole (not shown) for fixing to the second circular spline 212. The second surface 6b is flat and has a bolt hole (not shown) for fixing to the third flange 10. The first surface 6a and the second surface 6b are fixed by the connecting portion 6c. In the direction of the rotation axis of the second wave gear device 2, the central portion 5c of the third fixed portion 5 is located at the location of the connecting portion 6c. With this shape, the rotation of the second flexspline 222 is transmitted to the third flange 10, avoiding the central portion 5c of the third fixed portion 5. Furthermore, the connecting portion 6c may be provided only on the front side of the paper in FIG. 4, or may be provided symmetrically on the rear side of the paper with respect to the front side of the paper.

[0026] The fifth fixed part 7 connects the first bearing housing 17, which holds the third rotating shaft 14, to the second circular spline 212. Here, as described above, the second circular spline 212 is fixed to the first fixed plate 19 by the third fixed part 5. Fixing the fifth fixed part 7 to the first bearing housing 17 and the second circular spline 212 is preferably done using bolts. 4, in order to ensure the above-mentioned structure, the fifth fixing portion 7 has a portion corresponding to the outer diameter of the second circular spline 212 and a portion corresponding to the outer diameter of the first bearing housing 17. In addition, both portions have bolt holes (not shown) for fixing to the second circular spline 212 and the first bearing housing 17, respectively.

[0027] The first flange 8 connects the second fixed portion 4 and the first rotating shaft 12. For this reason, as shown in Fig. 3, the first flange 8 has a bolt hole (not shown) for fixing to the second fixed portion 4, and an insertion hole for connecting the first rotating shaft 12. The first rotating shaft 12 connected to the first flange 8 is preferably fixed by, for example, a bolt. The second flange 9 connects the first rotating shaft 12 and the second fixed disk 16. The second flange 9 has, for example, the same shape as the first flange 8. In other words, the second flange 9 and the first rotating shaft 12 are fixed together by inserting the first rotating shaft 12 into an insertion hole, and the second flange 9 and the second fixed disk 16 are fixed together by bolts.

[0028] The third flange 10 connects the fourth fixing portion 6 and the second rotating shaft 13. For this reason, as shown in Fig. 4, the third flange 10 has a bolt hole (not shown) for fixing to the fourth fixing portion 6, and an insertion hole for connecting the second rotating shaft 13. The second rotating shaft 13 connected to the third flange 10 is preferably fixed by, for example, a bolt. The fourth flange 11 connects the second rotating shaft 13 and the first fixed disk 15. The fourth flange 11 has, for example, the same shape as the third flange 10. In other words, the fourth flange 11 and the second rotating shaft 13 are fixed together by inserting the second rotating shaft 13 into an insertion hole, and the fourth flange 11 and the first fixed disk 15 are fixed together by a bolt.

[0029] The first rotating shaft 12, configured as described above, connects the first wave gearing 1 and the second fixed disk 16. The first rotating shaft 12 transmits the rotation input from the second fixed disk 16 to the first wave gearing 1. Alternatively, the first rotating shaft 12 transmits the rotation output from the first wave gearing 1 to the second fixed disk 16. The second rotating shaft 13, configured as described above, connects the second wave gear device 2 and the first fixed disk 15. The second rotating shaft 13 transmits the rotation input from the first fixed disk 15 to the second wave gear device 2. Alternatively, the second rotating shaft 13 transmits the rotation output from the second wave gear device 2 to the first fixed disk 15.

[0030] The third rotating shaft 14 connects the first wave generator 231 and the second wave generator 232. This connects the first wave gearing 1 and the second wave gearing 2 to each other. That is, in combination with the above-mentioned configuration, the first rotating shaft 12 and the second rotating shaft 13 are connected via the first wave gearing 1 and the second wave gearing 2. As a result, a structure is achieved in which a rotation input from the second fixed disk 16 is transmitted to the second rotating shaft 13 via the first rotating shaft 12, and a rotation input from the first fixed disk 15 is transmitted to the first rotating shaft 12 via the second rotating shaft 13.

[0031] The first fixed disk 15 is provided at one end of the differential mechanism 24. The first fixed disk 15 is a portion that is connected to other components when the differential mechanism 24 is incorporated, for example, as a part of a product or device. The first fixed disk 15 is rotatable about the axial direction of the second rotating shaft 13 as its central axis. This allows the rotation input from the components to be transmitted to the second rotating shaft 13. The second fixed disk 16 is provided at the other end of the differential mechanism 24. The second fixed disk 16 is a portion that is connected to other components when the differential mechanism 24 is incorporated as a part of a product or device, for example. The second fixed disk 16 is rotatable about the axial direction of the first rotating shaft 12 as its central axis. This allows the rotation input from the components to be transmitted to the first rotating shaft 12.

[0032] The first bearing housing 17 is in slidable contact with the third rotating shaft 14 in the circumferential direction. This serves to hold the third rotating shaft 14 in place so as to prevent it from wobbling when the third rotating shaft 14 rotates in the axial direction. The first bearing housing 17 is connected to the second circular spline 212 by the fifth fixed portion 7 as described above.

[0033] The second bearing housing 18 is fixed to a first fixed plate 19 and holds both axial ends of the first rotating shaft 12 and both axial ends of the second rotating shaft 13, as shown in Fig. 1. The second bearing housings 18 provided at both longitudinal ends of the differential mechanism 24 are held by second fixed plates 20.

[0034] The second fixed plate 20 is provided on both longitudinal ends of the first fixed plate 19. The second fixed plate 20 closes the openings at both longitudinal ends of the first fixed plate 19, thereby making the first fixed plate 19 box-shaped. This serves to reinforce the first fixed plate 19 and to hold the second bearing housings 18 provided at both ends of the first fixed plate 19. With this configuration, the first rotating shaft 12, the second rotating shaft 13 and the third rotating shaft 14 are fixed on the same straight line by the second bearing housings 18 and the first fixed plate 19 in the differential mechanism 24.

[0035] Next, the transmission of rotation between the first rotating shaft 12 and the second rotating shaft 13 in the differential mechanism 24 having the above-described configuration, via the first wave gear device 1 and the second wave gear device 2, will be described. First, consider a case in which the first circular spline 211 is fixed and the first flexspline 221 serves as the output with respect to the input from the first wave generator 231, as in the first wave gearing 1 shown in Fig. 1. In this case, the rotation of the first wave generator 231 is decelerated by the first flexspline 221, and the first flexspline 221 rotates in the reverse direction. Next, consider the case where the second flexspline 222 is fixed and the second circular spline 212 is used as the output with respect to the input from the second wave generator 232, as in the second strain wave gearing 2. In this case, the rotation of the second wave generator 232 is reduced in speed by the second circular spline 212, and the second circular spline 212 rotates in the same direction.

[0036] As described above, the first wave generator 231 of the first wave gearing 1 and the second wave generator 232 of the second wave gearing 2 are connected by the third rotating shaft 14. That is, the first wave generator 231 and the second wave generator 232 rotate in the same direction by the third rotating shaft 14. At this time, the first wave gearing 1 outputs rotation in the opposite direction to the rotation input from the third rotating shaft 14. Furthermore, the second wave gearing 2 outputs rotation in the same direction to the rotation input from the third rotating shaft 14. Therefore, in the differential mechanism 24, the first rotating shaft 12 and the second rotating shaft 13 rotate in opposite directions to each other due to the above-mentioned configuration.

[0037] With this configuration, for example, the rotation input to the first rotating shaft 12 is transmitted to the second rotating shaft 13 as follows. That is, first, the rotation input to the first rotating shaft 12 is transmitted to the first flexspline 221. The rotation input to the first flexspline 221 is accelerated by the first strain wave gearing 1 and output to the first wave generator 231 as rotation in the opposite direction. The rotation of the first wave generator 231 is transmitted to the second wave generator 232 connected to the third rotating shaft 14. The rotation of the second wave generator 232 is decelerated by the second strain wave gearing 2 and output to the second circular spline 212 as rotation in the same direction. The rotation of the second circular spline 212 is transmitted to the second rotating shaft 13. The rotation input to the second rotating shaft 13 is transmitted to the first rotating shaft 12 by going in the opposite direction to the above process.

[0038] As described above, in the wave gear device, the reduction ratio for the input from the wave generator 23 differs between when the circular spline 21 is fixed and when the flexspline 22 is fixed. Specifically, due to the structure of the wave gear device, the reduction ratio when the circular spline 21 is fixed is greater by 1 than the reduction ratio when the flexspline 22 is fixed.

[0039] For this reason, the first rotating shaft 12 connected to the first wave gearing 1 and the second rotating shaft 13 connected to the second wave gearing 2 do not output the same rotation speed. To address this, the reduction ratios of the wave gearings used in the first wave gearing 1 and the second wave gearing 2 can be increased to reduce the effect of the difference in reduction ratios to a negligible level. This makes it possible to prevent practical problems caused by the above-mentioned effect.

[0040] The differential mechanism 24 having the above-mentioned configuration is used in the following devices. That is, for example, it can be used in the arm of an industrial robot. Or, it can be used in the suspension mechanism of the vehicle R. In the following, as an example of the use of the differential mechanism 24 according to this embodiment, a case where it is used as a suspension mechanism of the vehicle R will be described.

[0041] 5 includes a differential mechanism 24, a first rocker arm 25, a second rocker arm 26, a first running mechanism 27, a second running mechanism 28, a third running mechanism 29, and a fourth running mechanism 30. The vehicle R is, for example, a lunar exploration vehicle. The first rocker arm 25 is provided on the right side in the traveling direction of the vehicle R, with its longitudinal direction parallel to the traveling direction. The first rocker arm 25 is provided with a first running mechanism 27 at its front end in the traveling direction, and a second running mechanism 28 at its rear end in the traveling direction. The second rocker arm 26 is provided on the left side in the traveling direction of the vehicle R, with its longitudinal direction parallel to the traveling direction. A third running mechanism 29 is provided at the front end of the second rocker arm 26 in the traveling direction, and a fourth running mechanism 30 is provided at the rear end in the traveling direction. The first running mechanism 27, the second running mechanism 28, the third running mechanism 29, and the fourth running mechanism 30 are all wheels of the vehicle R. These are driven by motors provided at the connection portions with the first rocker arm 25 and the second rocker arm 26, respectively.

[0042] The first rocker arm 25 and the second rocker arm 26 having the above-mentioned configuration are assembled into the vehicle R as follows. That is, as shown in Fig. 5, the center in the longitudinal direction of the first rocker arm 25 is connected to the first fixed disc 15, and the center in the longitudinal direction of the second rocker arm 26 is connected to the second fixed disc 16. Furthermore, based on the above-mentioned configuration, as shown in Fig. 6, a vehicle body 31 on which a storage facility for goods or a control panel or the like is mounted may be provided on the differential mechanism 24.

[0043] In the above-mentioned vehicle R, for example, consider a case where the third running mechanism 29 climbs over an obstacle such as a rock, as shown in FIG. 7. A rotational moment is generated in the second rocker arm 26 to which the third running mechanism 29 is attached, centered on the connection part with the second fixed disk 16. This rotational moment is transmitted to the first flexspline 221 via the second fixed disk 16, the second flange 9, the first rotating shaft 12, the first flange 8, and the second fixed part 4. As a result, the first flexspline 221 rotates, and rotates in the reverse direction at an increased speed by the reduction ratio of the first wave generator 231 and the first wave gear device 1.

[0044] Next, the rotation of the first wave generator 231 is transmitted to the second wave generator 232 via the third rotating shaft 14. As a result, the wave generators 23 of the first wave gear device 1 and the second wave gear device 2 rotate in the same direction at the same rotational speed. The rotation of the second wave generator 232 is transmitted to the second circular spline 212. The second circular spline 212 is decelerated by the reduction ratio of the second wave gear device 2 +1 and rotates in the same direction as the second wave generator 232.

[0045] After that, the rotation of the second circular spline 212 is transmitted to the first rocker arm 25 via the fourth fixed portion 6, the third flange 10, the second rotating shaft 13, the fourth flange 11, and the first fixed disk 15. As a result, a moment of rotation in the opposite direction to that of the second rocker arm 26 is generated in the first rocker arm 25, centered on the connection between the first fixed disk 15 and the first rocker arm 25. In the state shown in FIG. 7, this rotation moment acts in a direction that tries to push down the second running mechanism 28. At this time, when the first running mechanism 27 and the second running mechanism 28 attached to the first rocker arm 25 are grounded on the same plane, the differential mechanism 24 and the fourth running mechanism 30 rotate in the same direction as the second rocker arm 26. As a result, all of the first running mechanism 27, the second running mechanism 28, the third running mechanism 29, and the fourth running mechanism 30 can always be in contact with the ground. Therefore, higher running performance can be ensured.

[0046] As described above, according to the differential mechanism 24 of this embodiment, first, the rotation input to the first rotating shaft 12 is transmitted to the first flexspline 221. The rotation input to the first flexspline 221 is accelerated by the first strain wave gearing 1 and output to the first wave generator 231 as rotation in the opposite direction. The rotation of the first wave generator 231 is transmitted to the second wave generator 232 connected to the third rotating shaft 14. The rotation of the second wave generator 232 is decelerated by the second strain wave gearing 2 and output to the second circular spline 212 as rotation in the same direction. The rotation of the second circular spline 212 is transmitted to the second rotating shaft 13. The rotation input to the second rotating shaft 13 is transmitted to the first rotating shaft 12 by going in the opposite direction to the above-mentioned process.

[0047] In this way, while the first wave generator 231 and the second wave generator 232 connected by the third rotating shaft 14 rotate in the same direction, the first wave gear device 1 due to the above-mentioned configuration outputs rotation in the opposite direction to the rotation input from the first rotating shaft 12 to the third rotating shaft 14, and the second wave gear device 2 outputs rotation in the same direction as the rotation input from the third rotating shaft 14 to the second rotating shaft 13.

[0048] By adopting such a structure, the differential mechanism 24 can be made smaller and more rigid while suppressing vibration due to backlash. The above-described configuration can be suitably used in the field of industrial robots and the like, for example, when a differential mechanism 24 with reduced vibration is required.

[0049] Furthermore, first rocker arm 25 and second rocker arm 26, each equipped with a plurality of travel mechanisms at both ends in the longitudinal direction, passively rotate in opposite directions about a rotation axis that is perpendicular to the longitudinal direction. Here, let us assume that the vehicle R equipped with such a suspension mechanism is moving on flat ground by the running mechanism with the longitudinal direction of the first rocker arm 25 and the second rocker arm 26 as the travel direction. For example, when the running mechanism on the travel direction side of the first rocker arm 25 runs up a step, the first rotating shaft 12 to which the rocker arm is connected rotates with a change in the angle of the rocker arm. Accordingly, the second rotating shaft 13 rotates in the opposite direction to the first rotating shaft 12. This causes the second rocker arm 26 to rotate in a direction perpendicular to the longitudinal direction.

[0050] Such rotation of the second rocker arm 26 acts to press the traveling mechanism on the opposite side of the second rocker arm 26 to the vehicle direction against the ground when the traveling mechanism on the vehicle direction side of the second rocker arm 26 is used as a fulcrum. As a result, all traveling mechanisms other than the traveling mechanism that has climbed up the step can remain in contact with the ground. This allows the vehicle R to have better running performance on roads with poor surface conditions.

[0051] As described above, the differential mechanism 24 according to the present invention can be made small and highly rigid, and can further suppress vibration. Therefore, pitching and vibration of the vehicle body can be suppressed, and the vehicle R can run stably and be made small. The above-mentioned configuration can be suitably used for a vehicle R that travels on rough terrain such as the moon's surface or the desert. Specifically, the suspension mechanism can be suitably used for a lunar exploration vehicle, a material transport vehicle in the desert, etc.

[0052] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the first running mechanism 27, the second running mechanism 28, the third running mechanism 29, and the fourth running mechanism 30 are not limited to normal wheels, and may be crawler mechanisms. Or, normal wheels and crawler mechanisms may be mixed. For example, the first running mechanism 27 and the third running mechanism 29 at the front of the traveling direction of the vehicle R may be normal tires, and the second running mechanism 28 and the fourth running mechanism 30 at the rear of the traveling direction may be crawlers, or vice versa. Furthermore, in each of the above-described configurations, any portion described as being fixed by a bolt may be fixed by a method other than fastening with a bolt.

[0053] In addition, within the scope of the invention, the components in the above-described embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0054] 1. First wave gear device 2. Second wave gear device 3 1st fixed part 3a 1st side 3b Second side 3c Bottom 4 Second fixed part 5 Third fixed part 5a Top side 5b Bottom side 5c central part 6 4th fixed part 6a 1st page 6b 2nd side 6c Connecting part 7 5th fixed part 8 First flange 9 Second flange 10 Third flange 11 Fourth flange 12 First rotation axis 13 Second Rotation Axis 14 3rd rotation axis 15 First fixed disk 16 Second fixed disk 17 First bearing housing 18 Second bearing housing 19 1st fixed plate 20 Second fixing plate 21 Circular spline 22 Flexspline 23 Wave Generator 24 Differential mechanism 25 First rocker arm 26 Second rocker arm 27 First running mechanism 28 Second traveling mechanism 29 Third traveling mechanism 30 Fourth traveling mechanism 31 Body 211 1st Circular Spline 212 Second Circular Spline 221 First flexspline 222 Second Flexspline 231 1st Wave Generator 232 Second Wave Generator R Vehicle

Claims

1. A fixing plate and a first strain wave gear device including a first circular spline, a first flexspline, and a first wave generator, the first circular spline being fixed to the fixed plate; a first rotating shaft connected to the first flexspline; a second wave gear device including a second circular spline, a second flexspline, and a second wave generator, the second flexspline being fixed to the fixed plate; A second rotation shaft connected to the second circular spline; a third rotating shaft connecting the first wave generator and the second wave generator; Equipped with Differential mechanism.

2. A first rocker arm and a second rocker arm each having a plurality of travel mechanisms at both ends in a longitudinal direction; The differential mechanism according to claim 1 ; Equipped with A center of the first rocker arm in the longitudinal direction is connected to the first rotation shaft perpendicular to the longitudinal direction, A center of the second rocker arm in the longitudinal direction is connected to the second rotation shaft perpendicular to the longitudinal direction, The first rocker arm and the second rocker arm passively rotate in opposite directions about the first rotation axis or the second rotation axis. Suspension mechanism.

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