Steering device

Abstract

Provided is a steering device (S) comprising: a steering column (C) attached to a vehicle; a steering shaft (A) attached to the steering column (C) so as to be capable of relative rotation with respect to the steering column (C); a first gear (Ga) as an input gear provided on the steering shaft (A); and a second gear (Gb) and a third gear (Gc) having a rotation axis (X2) parallel with a rotation axis (X1) of the first gear (Ga). A stopper (1), which abuts to restrict the rotation of the steering shaft (A) when a predetermined relative rotation phase difference occurs in two of the gears (Ga, Gb, Gc) which are coaxial and have the same rotation direction, is disposed on the two gears or on each of one of the two gears and the steering column (C).

Description

[Technical Field]

[0001] The present invention relates to a steering device in which the rotation of a steering shaft is restricted when the steering shaft is rotated a predetermined number of times. In particular, in the case of a steer-by-wire system in which the rotation of the steering shaft is converted into electrical information to control the steering angle of a vehicle, the steering device itself may be provided with a rotation restricting mechanism. [Background technology]

[0002] Conventionally, an example of such a steering device is the device shown in Patent Document 1 (see

[0016] to

[0020] and Figs. 1 to 4).

[0003] This conventional technology regulates the rotation speed of a steering shaft 16, to which a steering wheel is fixed, to a predetermined number of rotations. The steering shaft 16 is rotatably disposed in a column jacket 18, and a regulation mechanism is provided between the steering shaft 16 and the column jacket 18.

[0004] Specifically, the column jacket 18 has an end stop 14 integrally formed to protrude inward of the column jacket 18. An annular fixed plate 20 that rotates integrally with the steering shaft 16 is attached to one of the steering shafts 16. A drive tab 22 is formed on a portion of the fixed plate 20, extending radially outward from a radially outer surface 24 and extending axially therefrom.

[0005] A plurality of rotating plates 26 are provided between the drive tabs 22 and the end stop 14. The rotating plates 26 are rotatable relative to the steering shaft 16, and portions of the rotating plates 26 are formed with driven tabs 28 that extend radially outward and axially therefrom, similar to the fixed plates 20.

[0006] When the fixed plate 20 rotates in conjunction with the rotation of the steering shaft 16, the drive tab 22 of the fixed plate 20 abuts against the driven tab 28 of the nearest rotating plate 26, driving that rotating plate 26 to rotate. In this way, the adjacent rotating plates 26 are driven to rotate, and the driven tab 28 of the outermost rotating plate 26 abuts against the end stop 14, determining the maximum rotational position of the steering shaft 16. In this way, over-rotation of the steering shaft 16 is prevented, and various wiring breakages are prevented. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US2018 / 0105198 A1 Summary of the Invention [Problem to be solved by the invention]

[0008] In the above-mentioned conventional technology, the stopper mechanism is configured across the steering shaft 16 and the column jacket 18. In other words, in order to exert a regulating function between the steering shaft 16, which rotates a predetermined number of times to the left and right, and the column jacket 18, which is a stationary body, it is necessary to arrange multiple rotating plates 26 between the endmost fixed plate 20 and the end stop 14, and to ensure a relative rotation angle between each of the rotating plates 26.

[0009] Therefore, this technology requires multiple rotating plates 26 and spacer plates 32, resulting in an excessive number of parts. As a result, vibrations and noise are likely to occur when each part operates, resulting in a poor operational feel. In addition, because many parts must be installed when assembling the steering device, measures to prevent incorrect assembly and missing parts, and parts management work, etc., become cumbersome.

[0010] As described above, conventional steering devices still have problems to be solved, and there has been a demand for a steering device that has a simple structure and generates less vibration and noise. [Means for solving the problem]

[0011] (First characteristic configuration) The steering device according to the present invention has the following characteristic configuration: a steering column attached to a vehicle; a steering shaft attached to the steering column so as to be rotatable relative to the steering column; a first gear as an input gear provided on the steering shaft; a second gear and a third gear having rotation axes parallel to the rotation axis of the first gear, The feature is that stoppers are provided on the two gears, or on one of the two gears and the steering column, which abut against each other to restrict the rotation of the steering shaft when a predetermined relative rotational phase difference occurs between two of these gears that are coaxial and rotate in the same direction.

[0012] (effect) As in this configuration, for example, by providing stoppers that abut against each other on two coaxial gears that rotate in the same direction, the steering shaft rotates a predetermined number of times, and when the relative rotational phase between the two gears reaches a predetermined value, the rotation of the steering shaft is restricted. This configuration also reduces the number of components. Furthermore, since all components are made up of gears with parallel rotational axes, the rotational drive is transmitted smoothly, reducing the generation of abnormal noise due to vibration, resulting in a rational steering device.

[0013] (Second characteristic configuration) In the steering device according to the present invention, it is advantageous if the stoppers are formed on two gears having the same rotation direction, one of which is a first convex portion formed outward along the radial direction of the rotation axis, and the other is a second convex portion formed inward along the radial direction of the rotation axis, and the two gears are formed so as to overlap when viewed in a direction perpendicular to the rotation axis.

[0014] (effect) In this configuration, the first and second protrusions serving as stoppers are formed to protrude along the radial direction of the rotation axis of two gears that rotate in the same direction, and these two gears overlap when viewed in a direction perpendicular to the rotation axis.

[0015] In this configuration, for example, one gear is supported in a recess provided in the other gear. In this case, the contact area between the two gears is increased, stabilizing the posture of the two gears during relative rotation. As a result, the engagement between the first and second convex portions is more reliable, making it possible to thin the first and second convex portions and at least one of the gears, resulting in a more compact steering device.

[0016] Furthermore, when assembling the two gears, it is possible to combine them in advance, thereby reducing the number of assembly steps.

[0017] (Third characteristic configuration) In the steering device of the present invention, the first gear is at least one external gear, and at least two internal gears are provided, each of which is attached to the steering column so as to mesh with the at least one external gear, and which include a first internal gear as the second gear and a second internal gear as the third gear, each having a different number of teeth from each other, and the stopper can be arranged on the first internal gear and the second internal gear, or on the first internal gear and the steering column.

[0018] (effect) In this configuration, an external gear is provided on the steering shaft of a vehicle, which rotates in conjunction with the rotation of the steering shaft, and this external gear rotates at least two internal gears. At this time, the internal gears rotate at different speeds. To achieve different rotational speeds, the numbers of teeth of the meshing external gears and internal gears are set as desired.

[0019] Generally, the number of teeth of the internal gear is greater than that of the external gear, so the rotation angle of the internal gear is smaller than that of the steering shaft. When the steering shaft is rotated, two or more internal gears rotate at a slower speed than the steering shaft, and the internal gears also gradually rotate relative to each other.

[0020] (Fourth characteristic configuration) In the steering device according to the present invention, at least two planetary gears are supported by a carrier fixed to the steering shaft as the external gear, the first internal gear and the second internal gear mesh with the planetary gear, and the second internal gear cannot rotate relative to the steering column, It is advantageous if the revolution axis of the planetary gear is set to coincide with the rotation axis.

[0021] (effect) In this configuration, a carrier equipped with multiple planetary gears is attached to the steering shaft, and these planetary gears mesh with a rotatable first internal gear and a second internal gear fixed to the steering column.

[0022] By meshing multiple planetary gears with the internal gear as in this configuration, it is possible to evenly distribute the meshing points of the two around the rotational axis of the steering shaft, which eliminates the inconvenience of the steering shaft becoming misaligned due to reaction forces generated by the meshing of the planetary gears with each internal gear, and simplifies the support structure for the steering shaft.

[0023] Furthermore, by providing multiple planetary gears on the steering shaft, the meshing reaction force borne by each planetary gear is reduced, and the strength required for the planetary gears can be lowered. As a result, the planetary gears can be made of resin, for example, which reduces manufacturing man-hours and costs, and also makes it possible to further reduce the weight of the device.

[0024] In this configuration, the revolution axes of the multiple planetary gears are the same as the rotation axes of the first internal gear and the second internal gear. Therefore, even when the first internal gear and the second internal gear are in contact with each other, by further rotating the steering shaft, the steering shaft, the first internal gear, and the second internal gear can rotate together. To prevent this, for example, the second internal gear is configured to be unable to rotate relative to the steering column.

[0025] (5th characteristic configuration) In the steering device according to the present invention, the external gear is a single first external gear fixed coaxially with the steering shaft, The first internal gear and the second internal gear can be configured to mesh with the first external gear, and the rotational axis of the first internal gear and the second internal gear can be made different from the rotational axis of the external gear.

[0026] (effect) In this configuration, the first internal gear and the second internal gear are driven by a single first external gear fixed to the steering shaft. With this configuration, the internal gears can be rotated differentially with an extremely small number of components. This allows for a lightweight steering device with a simple and compact structure.

[0027] (Sixth characteristic configuration) In the steering device according to the present invention, the external gears include a first external gear and a second external gear that are coaxial with the steering shaft and have different numbers of teeth from each other, The first internal gear may be configured to mesh with the first external gear, and the second internal gear may be configured to mesh with the second external gear.

[0028] (effect) In this configuration, a first external gear and a second external gear with different numbers of teeth are provided on a steering shaft, and the first internal gear and the second internal gear are meshed with the respective external gears. In this case, it becomes easier to select the reduction ratio between the first external gear and the first internal gear, and the reduction ratio between the second external gear and the second internal gear, increasing the degree of freedom in setting the reduction ratio of the entire steering device. As a result, it becomes easier to set the external shape of the device according to the mounting target. Furthermore, there is a wider range of options for setting the dimensions and materials of each gear depending on the reaction force generated when they mesh.

[0029] (7th characteristic configuration) In the steering device according to the present invention, the first gear is a first external gear, the second gear is a second external gear that is rotatably supported by the first external gear concentrically with the first external gear and has a number of teeth different from that of the first external gear, the third gear is at least one third external gear that simultaneously meshes with the first external gear and the second external gear and is rotatably supported by the steering column, The stopper may be arranged on each of the first external gear and the second external gear.

[0030] (effect) In this configuration, since internal gears are not used as the first to third gears, assembly and connection of the steering shaft and the like becomes easier.

[0031] Furthermore, since the third gear is fixed to the steering column in a state where it is externally meshed with the first gear and the second gear, the mounting structure is simple and the support member can be configured compactly.

[0032] Furthermore, by arranging multiple third gears around the first gear and the second gear, when high torque is input to the first gear, it is possible to prevent each third gear from separating from the first gear and the second gear, thereby maintaining a reliable gear transmission function.

[0033] (8th characteristic configuration) In the steering device of the present invention, the first internal gear and the second internal gear having the same rotation axis are provided as the internal gear, and it is advantageous that a plurality of stoppers are provided, the contact points of each of the stoppers are evenly distributed around the circumferential direction of the rotation axis, and each of the stoppers is configured to contact at the same time.

[0034] (effect) If the internal gears have the same rotation axis as in this configuration, it becomes easy to control the relative rotation speed between the internal gears. In particular, it becomes extremely easy to position the stoppers installed on both internal gears.

[0035] Furthermore, by providing multiple stoppers and distributing them evenly around the rotation axis when they come into contact, misalignment of the rotation axes of the internal gears is unlikely to occur when the stoppers come into contact with each other, which simplifies the support structure for the internal gear in particular and makes it possible to obtain a steering device that is less likely to produce abnormal noise.

[0036] (9th characteristic configuration) In the steering device of the present invention, at least one biasing member is provided across the first internal gear and the second internal gear, and the steering device can be configured to return the relative rotational phase between the first internal gear and the second internal gear to a reference phase.

[0037] (effect) With this configuration, the steering shaft can be returned to the reference phase when assembling the steering shaft or when there is no load after assembly, thereby facilitating assembly work.

[0038] Furthermore, when the vehicle is being driven, the steering tends to return to a reference phase, for example, a neutral position, which improves driving stability when traveling straight, and prevents excessive steering operation when turning because the steering force increases according to the steering angle. [Brief explanation of the drawings]

[0039] [Figure 1] FIG. 1 is an external view showing a configuration of a steering device according to a first embodiment; [Figure 2] FIG. 1 is an explanatory diagram showing a configuration of a steering device according to a first embodiment; [Figure 3] FIG. 1 is a cross-sectional view showing a configuration of a steering device according to a first embodiment. [Figure 4] FIG. 1 is a cross-sectional view showing a main configuration of a steering device according to a first embodiment; [Figure 5] FIG. 10 is an explanatory diagram showing the configuration of a steering device according to a second embodiment; [Figure 6] FIG. 10 is a cross-sectional view showing the configuration of a steering device according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing the configuration of a main part of a steering device according to a second embodiment. [Figure 8] FIG. 10 is an external view showing the configuration of a steering device according to a third embodiment. [Figure 9] FIG. 10 is an explanatory diagram showing the configuration of a steering device according to a third embodiment; [Figure 10] FIG. 11 is a cross-sectional view showing the configuration of a steering device according to a third embodiment. [Figure 11] FIG. 10 is a front view showing the main configuration of a steering device according to a fourth embodiment. [Figure 12] FIG. 11 is a perspective view showing a main configuration of a steering device according to a fifth embodiment. [Figure 13] FIG. 10 is an explanatory diagram showing the configuration of a steering device according to a fifth embodiment. [Figure 14] FIG. 11 is a cross-sectional view showing a main configuration of a steering device according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0040] (overview) A steering device S according to the present invention is attached to, for example, a steering shaft A of a vehicle, and has a function of restricting the rotation of the steering shaft A when the steering shaft A rotates through a predetermined angle. The steering device S includes a steering column C attached to the vehicle, and a steering shaft A attached to the steering column C so as to be rotatable relative to the steering column C.

[0041] In the present invention, all of the members that restrict the rotation of the steering shaft A are in a gear train relationship and are composed of gears with parallel rotation axes. For example, a first gear Ga is provided as an input gear on the steering shaft A. Furthermore, a second gear Gb and a third gear Gc are provided so as to be rotatable in conjunction with the first gear Ga.

[0042] In the present invention, two of these gears are arranged coaxially and rotate in the same direction, and are provided with stoppers 1 that abut against each other. In other words, these two gears are configured to rotate differentially, so that, for example, when a predetermined relative rotational phase difference occurs between them, stoppers 1 function to restrict the rotation of steering shaft A. There are various configurations for stoppers 1; for example, stoppers 1 may be formed on each of the two gears, or stoppers 1 may be formed on one of the two gears and on the steering column C. Furthermore, stoppers 1 may be provided one for each of the two gears, or multiple stoppers 1 may be provided on each of the two gears. Several embodiments of the present invention are shown below.

[0043] [First embodiment] A steering device S of a first embodiment is shown in Figs. 1 to 4. Fig. 1 shows the external appearance of the steering device S. The main parts of this embodiment, such as the gears, are provided at the base end of a steering column C. In Fig. 1, each gear is shown with its end open to make it easier to understand the structure of the main parts. Fig. 2 is a schematic diagram showing the component gears, and Fig. 3 shows a cross-sectional view of the steering device S.

[0044] In this embodiment, one external gear G serving as a first gear Ga is attached to the end of the steering shaft A. A first internal gear g1 serving as a second gear Gb and a second internal gear g2 serving as a third gear Gc mesh with this external gear G. Specifically, as shown in FIGS. 2 and 3 , the first internal gear g1 and the second internal gear g2 are provided inside the steering column C and rotate relative to each other about a second rotational axis X2 different from the first rotational axis X1 of the steering shaft A. The second internal gear g2 is cup-shaped, and the first internal gear g1 is accommodated therein. That is, the first internal gear g1 and the second internal gear g2 are formed to overlap when viewed in a direction perpendicular to the rotational axis X2, and the outer peripheral surface of the first internal gear g1 is rotationally guided by the inner peripheral surface of the second internal gear g2. The second internal gear g2 is mounted in a recess formed in the steering column C so as to be rotatable about the second rotational axis X2. With this configuration, the contact area between the first internal gear g1 and the second internal gear g2 increases, stabilizing the postures of the two gears during relative rotation.

[0045] Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3. As shown in Figs. 4 and 2, a stopper 1 is provided between the first internal gear g1 and the second internal gear g2, which abut against each other to prevent relative rotation. A plurality of first protrusions 11 functioning as the stopper 1 are formed on the outer surface of the first internal gear g1. The first protrusions 11 are formed outward from the outer surface of the first internal gear g1 in the radial direction of the second rotational axis X2. Meanwhile, second protrusions 12 are formed inward from the inner surface of the second internal gear g2 in the radial direction of the second rotational axis X2. A plurality of first protrusions 11 and second protrusions 12 are provided along the circumferential direction.

[0046] The number of teeth of the first internal gear g1 is different from the number of teeth of the second internal gear g2, and the first internal gear g1 and the second internal gear g2 rotate at different speeds with the rotation of the external gear G. Accordingly, when the steering shaft A rotates a predetermined number of times, the first convex portion 11 and the second convex portion 12 come into contact with each other in the circumferential direction, and the rotation of the steering shaft A is prevented.

[0047] Normally, the number of teeth of the internal gear g is greater than the number of teeth of the external gear G, so the rotation angle of the internal gear g is small compared to the rotation angle of the steering shaft A. When the steering shaft A is rotated, the first internal gear g1 and the second internal gear g2 rotate relatively, each slower than the steering shaft A and at different rotational speeds.

[0048] In this configuration, the stopper 1 functions when the steering shaft A rotates a predetermined number of times and the relative rotation angle between the first internal gear g1 and the second internal gear g2 reaches the desired set angle. By using a rotation restriction mechanism that utilizes the difference in the number of teeth in this way, the number of components can be minimized. Furthermore, because all components, including the external gear G and the internal gear g, are meshed, there is little abnormal noise due to vibration.

[0049] In this configuration, the first internal gear g1 and the second internal gear g2 are driven by a single first external gear G1 fixed to the steering shaft A, resulting in an extremely small number of components. Furthermore, the first convex portion 11 and the second convex portion 12 serving as the stopper 1 are allocated and arranged relative to the first internal gear g1 and the second internal gear g2, which stabilize their respective postures during relative rotation, ensuring reliable engagement between the first convex portion 11 and the second convex portion 12. This allows for the thinning of the first convex portion 11 and the second convex portion 12, or the thinning of at least one of the gears, resulting in a compact and lightweight steering device S. Furthermore, the first internal gear g1 and the second internal gear g2 can be assembled in advance, reducing the number of assembly steps.

[0050] 4, a plurality of first protrusions 11 and second protrusions 12 are provided along the circumferential direction. The contact points of these first protrusions 11 and second protrusions 12 are evenly distributed along the circumferential direction centered on the second rotation axis X2, and all contact each other at the same time.

[0051] If the first internal gear g1 and the second internal gear g2 are configured to rotate on the same axis, it becomes particularly easy to position the stopper 1 relative to the first convex portion 11 and the second convex portion 12, and it becomes easier to synchronize the timing of contact between the first convex portion 11 and the second convex portion 12. By generating the restricting forces simultaneously, the load borne by the first convex portion 11 and the second convex portion 12 to apply the restricting forces to the steering shaft A is dispersed, making it less likely that damage will occur to the first convex portion 11, etc. Furthermore, since the contact vibrations of the stoppers 1 that are transmitted to the steering shaft A are generated simultaneously, an excellent operability is also achieved.

[0052] Furthermore, since the multiple stoppers 1 are evenly distributed around the second rotation axis X2, misalignment of the first internal gear g1 and the second internal gear g2 is unlikely to occur when the respective stoppers 1 come into contact with each other. This simplifies the support structure for the internal gear g, and makes it possible to obtain a steering device S that is less likely to produce abnormal noise.

[0053] Second Embodiment 5 to 7 show an example in which a first external gear G1 and a second external gear G2 with different numbers of teeth are fixed around a first rotational axis X1 of the steering shaft A as the first gear Ga serving as an input gear. Here, a first internal gear g1 meshing with the first external gear G1 functions as a second gear Gb, and a second internal gear g2 meshing with the second external gear G2 functions as a third gear Gc. The first external gear G1 and the second external gear G2 rotate around the first rotational axis X1, and the first internal gear g1 and the second internal gear g2 rotate around a second rotational axis X2 different from the first rotational axis X1.

[0054] 6, the first internal gear g1 is supported and rotationally guided inside the second internal gear g2 journaled to the steering column C. In this embodiment, the number of teeth of the first external gear G1 is different from the number of teeth of the second external gear G2, which increases the degree of freedom in combining the first internal gear g1 and the second internal gear g2.

[0055] In the first embodiment, there was only one external gear G, and the tooth profiles of the first internal gear g1 and the second internal gear g2 that meshed with it had to be identical or similar. Therefore, once the outer diameters of both internal gears g were specified to a certain extent, the range of pitch circle options was limited to a certain extent so that the circumferential length of the pitch circle was an integer multiple of the number of teeth.

[0056] However, in this embodiment, by changing the tooth profiles of the first external gear G1 and the second external gear G2, the range of options for the pitch circle of the first internal gear g1 and the pitch circle of the second internal gear g2 is expanded. This increases the degree of freedom in setting the rotation speed until the rotation of the steering shaft A is restricted. As a result, it becomes easier to select the reduction ratio between the first external gear G1 and the first internal gear g1 and the reduction ratio between the second external gear G2 and the second internal gear g2. Furthermore, the range of options for setting the dimensions and materials of each gear is expanded depending on the reaction force generated when the gears are meshed, making it easier to set the external shape of the steering device S according to the installation target portion.

[0057] Third Embodiment An example of a steering device S according to this embodiment is shown in Figs. 8 to 10. Fig. 8 shows the external appearance of the steering device S, and Fig. 10 shows its internal structure. In this embodiment, the first gear Ga, which is the input gear, is made up of two planetary gears P, and a carrier CP equipped with these planetary gears P is provided on the steering shaft A. The two planetary gears P revolve around the first rotational axis X1 of the steering shaft A. In Fig. 8, each gear is shown with its end open to make it easier to understand the structure of the main parts.

[0058] 9 and 10, a first internal gear g1 serving as the second gear Gb and a second internal gear g2 serving as the third gear Gc mesh with these planetary gears P. The number of teeth of the first internal gear g1 and the number of teeth of the second internal gear g2 are different, and the first internal gear g1 and the second internal gear g2 rotate relatively at different speeds as the planetary gears P rotate. When the steering shaft A has rotated a predetermined number of times, the first convex portion 11 of the first internal gear g1 and the second convex portion 12 of the second internal gear g2 come into contact, restricting the rotation of the steering shaft A.

[0059] In this embodiment, too, the first internal gear g1 is held within the second internal gear g2. However, the second internal gear g2 is fixed to the steering column C. In this configuration, the revolution axis of the multiple planetary gears P, i.e., the first rotation axis X1, and the second rotation axis X2 of the first internal gear g1 and the second internal gear g2 are the same. Therefore, even when the first internal gear g1 and the second internal gear g2 are in contact with each other, by further rotating the steering shaft A, the steering shaft A, the first internal gear g1, and the second internal gear g2 can rotate integrally. To prevent this, for example, the second internal gear g2 is configured to be unrotatable relative to the steering column C.

[0060] In this configuration, where multiple planetary gears P mesh with the first internal gear g1 and the second internal gear g2, the meshing points can be evenly arranged around the first rotational axis X1 of the steering shaft A. As a result, the problem of the steering shaft A becoming misaligned due to reaction forces generated by meshing between the planetary gears P and the respective internal gears g is eliminated, and the support structure for the steering shaft A can be simplified.

[0061] Furthermore, by providing multiple planetary gears P on the steering shaft A, the meshing reaction force borne by each planetary gear P is reduced, thereby lowering the required strength of the planetary gear P. As a result, the planetary gears P can be made of a resin material, for example, which reduces the number of manufacturing steps and costs, and also makes it possible to further reduce the weight of the device.

[0062] [Fourth embodiment] An example of a steering device S of this embodiment is shown in FIG. 11. Here, an example is shown in which at least one biasing member 2 is provided across a configuration including a first internal gear g1 and a second internal gear g2. For example, a coil spring 2a as an example of the biasing member 2 is attached in the circumferential direction about the first rotation axis X1 across the first convex portion 11 of the first internal gear g1 and the second convex portion 12 of the second internal gear g2. This provides a reference phase between the first internal gear g1 and the second internal gear g2. It is convenient to set this reference phase, for example, to a neutral position on the left or right of the steering axis A.

[0063] Even when the coil spring 2a is provided, the first convex portion 11 and the second convex portion 12 must come into contact with each other to restrict rotation of the steering shaft A. When the coil spring 2a is used, the first convex portion 11 and the second convex portion 12 are provided with concave spring retainers 2b on their circumferentially facing sides, into which the coil spring 2a can enter. When the first convex portion 11 and the second convex portion 12 come into contact with each other, the two spring retainers 2b face each other to form a space, and the compressed coil spring 2a is housed inside.

[0064] It should be noted that various shapes of the biasing member 2 can be used, and the shape of the biasing member 2 attached to the first convex portion 11 and the second convex portion 12 can be set appropriately.

[0065] With this configuration, the steering shaft A can be returned to the reference phase when assembling the steering shaft A or when there is no load after assembly, making the assembly work easier.

[0066] Furthermore, when the vehicle is being driven, the steering tends to return to a reference phase, for example, a neutral position, which improves driving stability when traveling straight, and prevents excessive steering operation when turning because the steering force increases according to the steering angle. Furthermore, the configuration of this embodiment is applicable to a configuration in which the first convex portion 11 and the second convex portion 12 abut along the circumferential direction, and can be applied to the configurations of the first to third embodiments described above, as well as the configuration of the fifth embodiment described below.

[0067] Fifth Embodiment A steering device S of the fifth embodiment is shown in Figures 12 to 14. Figure 12 is a perspective view of this configuration, Figure 13 is a schematic view of this configuration, and Figure 14 is a cross-sectional view.

[0068] In this embodiment, a first external gear G1 serving as a first gear Ga is attached to an end of the steering shaft A. A second external gear G2 serving as a second gear Gb is provided coaxially with the first external gear G1. The first external gear G1 and the second external gear G2 share the same first rotation axis X1. Three third external gears G3 serving as a third gear Gc mesh with the first external gear G1 and the second external gear G2. The three third external gears G3 are arranged at equal positions along the outer periphery of the first external gear G1.

[0069] As in the other embodiments, the first external gear G1 is fixed to the end of the steering shaft A. This fixing can be achieved by various means, such as engagement or engagement with serration grooves. A toothed portion with a predetermined number of teeth is formed on the outer edge of the first external gear G1. In FIG. 12, the toothed portion is formed by a simple spur gear. However, it may also be a helical gear with inclined tooth traces.

[0070] The first external gear G1 has a small-diameter boss G1a formed adjacent to the tooth portion. This boss G1a has, for example, three first protrusions 11 formed as stoppers 1 that are dispersed along the circumferential direction and protrude radially outward. The number of first protrusions 11 is arbitrary.

[0071] An annular second external gear G2 is rotatably supported on this boss portion G1a. Three second protrusions 12 serving as stoppers 1 are formed on the inner peripheral surface of the second external gear G2. These second protrusions 12 protrude radially inward and are distributed along the circumferential direction. These second protrusions 12 also contribute to maintaining the position of the second external gear G2; the tip faces of the first protrusions 11 of the first external gear G1 are close to the inner peripheral surface of the second external gear G2, and the tip faces of the second protrusions 12 of the second external gear G2 are close to the outer peripheral surface of the boss portion G1a of the first external gear G1, thereby maintaining the two gears coaxially.

[0072] The first external gear G1 and the second external gear G2 both mesh with the third external gear G3. However, there is a difference between the number of teeth of the first external gear G1 and the number of teeth of the second external gear G2. Because the third external gear G3 has only one toothed portion, a rotational phase difference occurs between the first external gear G1 and the second external gear G2, which rotates in accordance with the rotation of the third external gear G3. As a result, when the steering shaft A rotates a predetermined number of times, the first convex portion 11 and the second convex portion 12 come into contact, restricting the rotation of the steering shaft A. Note that as an alternative configuration for the third external gear G3, a stepped gear with external teeth having a different number of teeth may be used at the portion meshing with the first external gear G1 or the second external gear G2, respectively.

[0073] As shown in FIG. 12, the three third external gears G3 are journaled to the steering column C using a fixed cover Ca. The fixed cover Ca is fixed to the end face of the steering column C using fastening members T such as bolts. One end of the support shaft G3x of the third external gear G3 is fixed to the steering column C, and the other end of the support shaft G3x is supported by the fixed cover Ca. A bearing portion Cax that receives the other end of the support shaft G3x is formed in the fixed cover Ca. The bearing portion Cax may be, for example, a simple recess into which the end of the support shaft G3x is inserted.

[0074] According to this configuration, the support shaft G3x of the third external gear G3 has a double-supported structure, so that the third external gear G3 does not slip outward when rotating and meshing with the first external gear G1 and the second external gear G2, thereby ensuring a reliable gear transmission function.

[0075] Furthermore, this configuration uses only external gears, eliminating the need for the ring gear used in the above embodiments, which simplifies the device structure and simplifies assembly of the steering shaft and other components. [Industrial Applicability]

[0076] The steering device of the present invention can be widely used as a device in which the rotation of the steering shaft is restricted when the steering shaft has been rotated a predetermined number of times. [Explanation of symbols]

[0077] 1 Stopper 2. Pressurizing member A Steering axis C. Steering column CP Carrier Ga 1st gear Gb 2nd gear Gc 3rd gear G External gear G1 First external gear G2 Second external gear G3 3rd external gear g Internal gear g1 First internal gear g2 Second internal gear P planetary gear S Steering device X Rotation axis

Claims

1. A steering device (S) comprising: a steering column (C) attached to a vehicle; a steering shaft (A) attached so as to be rotatable relative to the steering column (C); a first gear (Ga) as an input gear provided on the steering shaft (A); and second gears (Gb) and third gears (Gc) having rotation axes (X2) parallel to a rotation axis (X1) of the first gear (Ga) and driven by the first gear (Ga), wherein stoppers (1) are disposed on the two gears or between one of the two gears and the steering column (C) to abut against each other when a predetermined relative rotation phase difference occurs between two of the gears (Ga, Gb, Gc) that are coaxial and rotate in the same direction, thereby restricting the rotation of the steering shaft (A).

2. 2. The steering device (S) according to claim 1, wherein the stopper (1) is formed on two gears having the same rotation direction, one of which is a first convex portion (11) formed outward along the radial direction of the rotation axis (X1, X2), and the other is a second convex portion (12) formed inward along the radial direction of the rotation axis (X1, X2), and the two gears are formed to overlap when viewed in a direction perpendicular to the rotation axis (X1, X2).

3. The first gear (Ga) is at least one external gear (G), At least two internal gears (g) are provided, the first internal gear (g1) serving as the second gear (Gb) and the second internal gear (g2) serving as the third gear (Gc), and the first internal gear (g1) and the second internal gear (g2) are attached to the steering column (C) so as to mesh with the at least one external gear (G), and have different numbers of teeth from each other; 3. A steering device (S) according to claim 2, wherein the stopper (1) is arranged on each of the first internal gear (g1) and the second internal gear (g2), or on each of the first internal gear (g1) and the steering column (C).

4. As the external gear (G), at least two planetary gears (P) are supported on a carrier (CP) fixed to the steering shaft (A), the first internal gear (g1) and the second internal gear (g2) mesh with the planetary gear (P), and the second internal gear (g2) cannot rotate relatively to the steering column (C); 4. A steering device (S) according to claim 3, wherein the revolution axis of said planetary gear (P) is set to be the same as said rotation axis (X1).

5. the external gear (G) is a single first external gear (G1) fixed coaxially with the steering shaft (A), 4. A steering device (S) according to claim 3, wherein the first internal gear (g1) and the second internal gear (g2) mesh with the first external gear (G1), and the rotation axis (X2) of the first internal gear (g1) and the second internal gear (g2) is different from the rotation axis (X1) of the external gear (G).

6. As the external gear (G), a first external gear (G1) and a second external gear (G2) are provided which are coaxial with the steering shaft (A) and have different numbers of teeth from each other, 4. The steering device (S) according to claim 3, wherein the first internal gear (g1) meshes with the first external gear (G1), and the second internal gear (g2) meshes with the second external gear (G2).

7. The first gear (Ga) is a first external gear (G1), the second gear (Gb) is a second external gear (G2) that is rotatably supported by the first external gear (G1) concentrically with the first external gear (G1) and has a number of teeth different from that of the first external gear (G1), the third gear (Gc) is at least one third external gear (G3) that simultaneously meshes with the first external gear (G1) and the second external gear (G2) and is rotatably supported by the steering column (C), 3. The steering device (S) according to claim 2, wherein the stopper (1) is disposed on each of the first external gear (G1) and the second external gear (G2).

8. 2. The steering device (S) according to claim 1, wherein a plurality of the stoppers (1) are provided, the contact points of the stoppers (1) are evenly distributed around the rotation axis (X1, X2) in the circumferential direction, and the stoppers (1) contact each other at the same timing.

9. A steering device (S) according to any one of claims 3 to 6, wherein at least one biasing member (2) is provided across each abutment point of the stopper (1), and is configured to return the relative rotational phase between the first internal gear (g1) and the second internal gear (g2) to a reference phase.

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