Planetary gear mechanism

Abstract

The utility model provides a kind of planetary gear mechanism can ensure strength, and, by making pinion itself have the elasticity generated by rigidity variation to inhibit meshing vibration.Stepped pinion (16 (16a, 16b, 16c)) has the circumferential rigidity variation characteristic G of different radial rigidity according to the position of circumference, and the rotation phase difference θb, θc of circumferential rigidity variation characteristic G is arranged between each stepped pinion 16a, 16b, 16c, to make in the meshing of each stepped pinion 16a, 16b, 16c and sun gear 12, the synthesis component of vibration generated respectively is smaller.Thereby, the magnitude of overall vibration caused by the meshing of stepped pinion 16a, 16b, 16c and sun gear 12 and the variation amplitude of amplitude is smaller.Therefore, both ensure strength, and inhibit meshing vibration by making pinion itself have the characteristic of rigidity variation.

Description

Technical Field

[0001] This utility model relates to a vibration suppression structure for planetary gear mechanisms. Background Technology

[0002] Planetary gear mechanisms, consisting of a sun gear, a planetary carrier, a ring gear, and multiple pinions of the same shape supported by the planetary carrier in a rotational and revolution-oriented manner, are well known. A technique has been disclosed in which, in a planetary gear mechanism with helical gears, variations in frictional torque generated between the pinions and other gears are suppressed by setting the number of teeth on each gear, the meshing clearance between the pinions and other gears, etc., thereby suppressing the generation of noise or vibration. For example, the planetary gear device described in Patent Document 1 is such a device.

[0003] However, in addition to the frictional torque variations between the pinion and other gears mentioned earlier, noise or vibration in planetary gear mechanisms also arises from the vibration generated when the pinion and other gears mesh, caused by the collision of their teeth (hereinafter referred to as meshing vibration). As countermeasures against this meshing vibration, in the past, precision machining of the gears was used to reduce meshing transmission errors, or soundproof covers or dynamic vibration dampers were installed at the points where meshing vibration is generated and propagated. On the other hand, as a countermeasure to suppress meshing vibration, it is considered to reduce the force of meshing and collision by making the pinion itself elastic, that is, by giving the pinion a rigidity-variable characteristic. For example, Patent Document 2 discloses a helical gear that, by providing multiple through holes in the disc portion (flange) between the hub (rotation shaft) and the rim portion (gear ring) of the helical gear, ensures strength while giving the gear itself a rigidity-variable characteristic to suppress vibration.

[0004] Existing technical documents

[0005] Patent documents

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2004-60694

[0007] [Patent Document 2] Japanese Patent Application Publication No. 2005-69401 Utility Model Content

[0008] The problem to be solved by the utility model

[0009] However, the content disclosed in Patent Document 2 concerns the technology of a single helical gear, and there is room for further improvement in planetary gear mechanisms with multiple meshing gears.

[0010] This invention was made against the background described above, and its purpose is to provide a planetary gear mechanism that can ensure strength and suppress meshing vibration by giving the pinion itself the characteristic of rigid variation.

[0011] Methods for solving problems

[0012] The present invention is aimed at (a) a planetary gear mechanism, equipped with: a sun gear, a planetary gear carrier, a gear ring, and a plurality of pinions of the same shape supported by the planetary gear carrier in a rotational and revolving manner, characterized in that (b) the pinions have a circumferential stiffness variation characteristic where the radial stiffness varies with the circumferential position, and (c) a rotational phase difference of the circumferential stiffness variation characteristic is provided between each of the pinions, so that the composite component of the vibrations generated in the meshing of each pinion with the sun gear is reduced.

[0013] Effects of the utility model

[0014] According to this invention, the pinion has a circumferential stiffness variation characteristic where the radial stiffness varies depending on the circumferential position. A rotational phase difference of this circumferential stiffness variation characteristic is provided between each pinion to reduce the composite component of vibrations generated during the meshing of each pinion with the sun gear. Consequently, the magnitude and amplitude of the overall vibration caused by the meshing of each pinion with the sun gear are reduced. Therefore, a planetary gear mechanism can be provided that ensures strength and suppresses meshing vibration by giving the pinions themselves a stiffness variation characteristic. Attached Figure Description

[0015] Figure 1 This is a diagram illustrating the schematic structure of the planetary gear mechanism employing this utility model.

[0016] Figure 2 This is an explanation Figure 1 The diagram shows the configuration of the pinion gears in the planetary gear mechanism used to suppress vibration.

[0017] Figure 3 This is a diagram illustrating the structure of the pinion equipped in a planetary gear mechanism corresponding to other embodiments of the present invention.

[0018] Explanation of reference numerals in the attached figures

[0019] 10, 20: Planetary gear mechanism; 12: Sun gear; 14: Ring gear; 16, 26: Stepped pinion (small gear); G, G2: Circumferential stiffness variation characteristics; θb, θb2, θc, θc2: Rotational phase difference. Detailed Implementation

[0020] Hereinafter, embodiments of this implementation will be described in detail with reference to the accompanying drawings. Furthermore, in the following embodiments, the drawings have been appropriately simplified or modified, and the dimensions and shapes of the various parts are not necessarily drawn correctly.

[0021] Example 1

[0022] Figure 1 This is a diagram illustrating the schematic structure of the planetary gear mechanism 10 employing this utility model. Figure 1 (a) is a perspective view of the planetary gear mechanism 10, which is a known stepped pinion type planetary gear mechanism, equipped with a sun gear 12, a planetary gear carrier (not shown), a ring gear 14, and three stepped pinions 16 (16a, 16b, 16c) supported by the planetary gear carrier in a rotational and revolving manner. The axis CL is the rotational axis of the sun gear 12, the ring gear 14, and the planetary gear carrier. Furthermore, the stepped pinions 16 (16a, 16b, 16c) are equivalent to the "pinions" of this invention.

[0023] Each of the stepped pinions 16a, 16b, and 16c is equipped with: large-diameter gears 16a1, 16b1, and 16c1 meshing with the sun gear 12; and small-diameter gears 16a2, 16b2, and 16c2 meshing with the ring gear 14. The large-diameter gears 16a1 and 16a2, 16b1 and 16b2, and 16c1 and 16c2 rotate as a single unit. The operation of the planetary gear mechanism 10 is well-known and therefore omitted from description.

[0024] Figure 1 (b) is from Figure 1 (a) is a perspective view of the stepped pinion 16a viewed from the forward axis CL. The large-diameter gear 16a1 of the stepped pinion 16a, which meshes with the sun gear 12, is supported by a disc-shaped flange F. At the flange F, as... Figure 1 As shown in (b), three approximately semi-circular through holes h are provided at equal intervals along the outer periphery RF of the flange F, with the outer diameter varying circumferentially. Furthermore, the stepped pinions 16b and 16c are also constructed with the same shape as the stepped pinion 16a. By providing the through holes h, strength is ensured for the stepped pinions 16 (16a, 16b, 16c), and they possess a circumferential stiffness variation characteristic G that varies with the radial stiffness depending on the circumferential position of the gear teeth.

[0025] Figure 1 (c) is a diagram showing a stepped pinion 16NA that does not employ the prior art of this invention. In the prior art, no through hole is provided on the flange FA of the large-diameter gear 16NA1. That is, it does not have the circumferential rigidity variation characteristic G, and the radial rigidity does not change.

[0026] Figure 1 (d) is a diagram illustrating the effect of the presence or absence of the through hole h on the suppression of meshing vibration caused by the collision of the teeth of the stepped pinion 16 (16a, 16b, 16c) and the sun gear 12 when they mesh. Figure 1 The solid line in (d) is equivalent to Figure 1 In case (b), a single-dot dash is equivalent to... Figure 1 (c) Case 1. When the stepped pinion 16 (16a, 16b, 16c) rotates, if there is a through hole h at the point of meshing with the sun gear 12, the stiffness variation caused by the circumferential stiffness variation characteristic G modulates the meshing point force, which is the force for meshing and collision. Therefore, compared to the case without the through hole h, as... Figure 1 As shown in (d), the peak value of the first-order component of the generated frequency is dispersed. Thus, the meshing vibration at the meshing point is suppressed.

[0027] Secondly, in Figure 2 The text describes the configuration of the stepped pinion 16 (16a, 16b, 16c) for suppressing meshing vibration, and the synthesis of meshing vibration. Figure 2 (a) is from Figure 1 (a) is a perspective view of the stepped pinions 16 (16a, 16b, 16c) and the sun gear 12, viewed from the forward axis CL, illustrating the configuration used to suppress meshing vibrations. The stepped pinions 16 (16a, 16b, 16c) are provided with a rotational phase difference of circumferential stiffness variation characteristic G between each other, so that the combined component of the individual meshing vibrations generated at the meshing points of each stepped pinion 16a, 16b, 16c and the sun gear 12 is reduced. For example, in… Figure 2 In (a), relative to the stepped pinion 16a being configured such that the meshing point with the sun gear 12 is located at the center of the through hole h, the stepped pinion 16b is configured with a rotational phase difference θb in the counterclockwise direction, and the stepped pinion 16c is configured with a rotational phase difference θc in the clockwise direction.

[0028] Figure 2 (b) and Figure 2 (c) is a diagram illustrating the circumferential stiffness variation characteristics G of the stepped pinions 16a, 16b, and 16c at the meshing point with the sun gear 12, and their composite composition. Figure 2 (b) illustrates an example of an embodiment of the present invention. Figure 2 (c) indicates a comparative example. Figure 2Both (b) and (c) show the rotation angle of each stepped pinion 16a, 16b, 16c when rotated 360 degrees counterclockwise from the configuration shown in the label box on the right side of the figure. The vertical axis represents the variation in rigidity of the stepped pinions 16a, 16b, 16c and their composite components at the meshing point with the sun gear 12. Since a larger value on the vertical axis indicates greater rigidity at the meshing point with the sun gear 12, a greater meshing force, and therefore, greater meshing vibration. That is, in Figure 2 In (b) and (c), the larger the value of the vertical axis becomes, the greater the meshing vibration becomes.

[0029] exist Figure 2 In the comparative example (c), as shown in the annotation box on the right side of the paper, the stepped pinions 16a, 16b, and 16c are configured with their meshing points with the sun gear 12 located at the center of each through hole h, i.e., with a rotational phase difference θb = rotational phase difference θc = 0°. When the stepped pinions 16a, 16b, and 16c rotate 360 ​​degrees counterclockwise from this state, the rigidity of the stepped pinions 16a, 16b, and 16c at the meshing points with the sun gear 12 is as follows: Figure 2 As shown in (c), the rigidity variation periodically ranges from the minimum value of the rigidity variation (the line at the vertical axis 0) to the maximum value of the rigidity variation S. This rigidity variation characteristic is equivalent to the circumferential rigidity variation characteristic G (the circumferential rigidity variation characteristics corresponding to the stepped pinions 16a, 16b, and 16c are Ga, Gb, and Gc). The reason for the repeated periodic variation is that three through holes h are provided at equal intervals in the circumferential direction. In the comparative example, since the rotational phase at the meshing point of the stepped pinions 16a, 16b, and 16c with the sun gear 12 is the same (θb = θc = 0°), the circumferential rigidity variation characteristics Ga, Gb, and Gc have the same waveform. Therefore, since the composite components of the circumferential rigidity variation characteristic G (=Ga + Gb + Gc) are as follows... Figure 2 (c) shows a waveform that varies by three times the size of the same waveform. Therefore, the overall meshing vibration of the stepped pinions 16a, 16b, 16c and the sun gear 12 is also generated and varies according to this changing waveform.

[0030] For the comparative example, Figure 2 (b) is an example embodiment where the rotational phase difference θb is 40° and the rotational phase difference θc is -40°. Figure 2 As shown in (b), due to the rotational phase differences θb and θc generated between the circumferential rigidity variation characteristics Ga, Gb, and Gc of the stepped pinions 16a, 16b, and 16c, the composite composition (=Ga+Gb+Gc) and Figure 2Compared to the comparative example in (c), the maximum value is smaller, and the magnitude of the variation is also smaller. As a result, the magnitude of the overall meshing vibration of the stepped pinions 16a, 16b, 16c and the sun gear 12 is also smaller, and the variation of the generated meshing vibration is also smaller.

[0031] Figure 2 (b) is an example of a rotational phase difference θb = 40° and a rotational phase difference θc = -40°. The rotational phase differences θb and θc are preferably set by pre-design or experiment based on the design and manufacturing conditions of the planetary gear mechanism 10, and also by pre-design or experiment based on mounting conditions such as on a vehicle. In addition, the number, size, and shape of the through holes h are also preferably set by pre-design or experiment.

[0032] As described above, in the planetary gear mechanism 10 of this embodiment, the stepped pinions 16 (16a, 16b, 16c) have a circumferential stiffness variation characteristic G that varies with their radial stiffness depending on their circumferential position. Rotational phase differences θb and θc of the circumferential stiffness variation characteristic G are provided between each stepped pinion 16a, 16b, 16c, so that the combined component of vibrations generated at the meshing points of each stepped pinion 16a, 16b, 16c with the sun gear 12 is reduced. Therefore, the magnitude and amplitude of the overall vibration caused by the meshing of the stepped pinions 16a, 16b, 16c with the sun gear 12 are reduced. Thus, strength is ensured, and meshing vibration is suppressed by giving the pinions themselves a stiffness variation characteristic.

[0033] Next, other embodiments of the present invention will be described. Furthermore, in the following description, the same reference numerals are used for the common parts of the embodiments, and their description is omitted.

[0034] Example 2

[0035] Figure 3 This diagram illustrates the structure of the stepped pinion 26 equipped in the planetary gear mechanism 20, corresponding to other embodiments of the present invention, and is equivalent to Embodiment 1 described above. Figure 2Figure (a) shows the planetary gear mechanism 20, which is an embodiment in which the stepped pinions 16 (16a, 16b, 16c) of the planetary gear mechanism 10 of Embodiment 1 are replaced with stepped pinions 26 (26a, 26b, 26c). The large-diameter gears (26a1, 26b1, 26c1) of the stepped pinions 26 are supported, for example, by a disc-shaped flange F2 with low rigidity and elasticity, and three ribs LB with high rigidity arranged at equal intervals in the circumferential direction and elongated in the radial direction to ensure strength. Thus, both strength is ensured and the circumferential rigidity variation characteristic G2, which varies with the radial rigidity according to the circumferential position, is realized. In addition, as in Embodiment 1, for the rotational phase difference at the meshing point with the sun gear 12, the stepped pinion 26b has a rotational phase difference θb2 relative to the stepped pinion 26a, and the stepped pinion 26c has a rotational phase difference θc2. The raw materials, dimensions, shapes, and rotational phase differences θb2 and θc2 of flange F2 and rib LB are preferably set through pre-design or experimentation.

[0036] In the planetary gear mechanism 20 configured as described above, the same effect as that of the planetary gear mechanism 10 of Embodiment 1 described above is also obtained.

[0037] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention may also be applied to other methods.

[0038] For example, in Embodiments 1 and 2 described above, planetary gear mechanisms 10 and 20 are equipped with stepped pinions 16 and 26. However, this invention is not limited to this method and can also be applied to planetary gear mechanisms with pinions of a single diameter.

[0039] In addition, in the aforementioned Embodiments 1 and 2, the stepped pinions 16 and 26 are composed of 3, but are not limited to 3. Even a suitable number of pinions is suitable for this utility model.

[0040] Furthermore, the above description is merely one implementation method, and this utility model can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

Claims

1. A planetary gear mechanism, comprising: a sun gear, a planetary gear carrier, a ring gear, and a plurality of pinions of the same shape supported by the planetary gear carrier in a rotational and revolution-enabled manner, characterized in that, The pinion has a circumferential stiffness variation characteristic, where the radial stiffness varies depending on the circumferential position. A rotational phase difference with the circumferential rigidity variation characteristic is provided between each of the pinions, so that the composite component of the vibrations that occur during the meshing of each pinion with the sun gear is reduced.

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