Speed reducer

Abstract

To provide a reduction gear, a drive unit, and a steering auxiliary device capable of outputting stable torque to the outside through an output arm without causing an increase in size and weight of the whole device and an increase in manufacturing man-hours.SOLUTION: A speed reducer includes an input rotor, a speed reduction mechanism part, and a cylindrical case 15. The speed reducer rotates by receiving power from the drive device. The speed reduction mechanism decelerates rotation of the input rotor. A cylindrical case 15 covers the outside of the speed reduction mechanism part and rotates by receiving the power reduced by the speed reduction mechanism part. The tubular case 15 is integrally formed with an output arm 27 that extends radially outward from the outer peripheral surface of the tubular case 15 and transmits the operating force to the outside.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reducer, a drive unit, and a steering assist device. [Background technology]

[0002] A steering assist device that assists a driver's steering operation by using hydraulic or electric motor power is known as a steering system device for a vehicle. The steering assist device includes a steering mechanism that steers the wheels in response to the operation of a steering unit (steering wheel), and a drive unit that outputs an assist force to the steering mechanism in response to the steering force applied to the steering unit (see, for example, Patent Document 1).

[0003] The drive unit used in the steering assist device includes a drive device such as an electric motor and a reducer that reduces the output of the drive device. The reducer includes an input rotor that receives power from the drive device and rotates, a reduction mechanism that reduces the rotation of the input rotor, and an output rotor that receives the power reduced by the reduction mechanism and rotates, and is configured to transmit the rotation of the output rotor to the steering mechanism. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-35475 Summary of the Invention [Problem to be solved by the invention]

[0005] A known reducer used in a steering assist device has a cylindrical case disposed radially outside a reduction mechanism, and the cylindrical case serves as an output rotor. In this reducer, an output arm for transmitting operating force to the steering mechanism is attached to the cylindrical case by bolts.

[0006] However, in this case, since the output arm is fixed to the cylindrical case by bolting, it is difficult to control the tightening force of the bolts, and if there is variation in the tightening force of the bolts, it becomes difficult to control the torque transmitted to the steering mechanism.

[0007] One solution to this problem is to provide a fixing flange on the outer periphery of the cylindrical case and fasten the output arm to that flange with multiple bolts. However, with this method, a thick flange must be provided on the outer periphery of the cylindrical case to accommodate the bolt fastening, and bolt insertion holes and screw holes must be formed in that flange, which makes the entire reducer prone to becoming large and heavy, and also increases the number of manufacturing steps.

[0008] The present invention provides a reducer, a drive unit, and a steering assist device that can output stable torque to the outside through an output arm without increasing the size and weight of the entire device or the number of manufacturing steps. [Means for solving the problem]

[0009] A reducer according to one aspect of the present invention comprises an input rotating body that rotates upon receiving power from a drive unit, a reduction mechanism that slows down the rotation of the input rotating body, and a cylindrical case that covers the outside of the reduction mechanism and rotates upon receiving the power reduced by the reduction mechanism, with the cylindrical case having an output arm integrally formed therewith that extends radially outward from the outer circumferential surface of the cylindrical case and transmits operating force to the outside.

[0010] The rotor may include a base block that rotatably supports the input rotor and the cylindrical case, the base block having a fixing flange that extends radially outward from a position adjacent to one axial end of the cylindrical case and is fixed to another member, and the output arm may extend radially outward from the other axial end of the cylindrical case.

[0011] A reducer according to one aspect of the present invention comprises a base block, a crankshaft having an eccentric rotating portion and rotatably supported on the base block while receiving power from a drive unit, an oscillating gear having external teeth on its outer periphery and rotating in an oscillating manner when it receives eccentric rotational force from the eccentric rotating portion, and a cylindrical case having internal teeth with a different number of teeth than the external teeth and rotating in mesh with the external teeth while rotatably supported on the base block, wherein an output arm extending radially outward from the outer periphery of the cylindrical case and transmitting operating force to the outside is integrally formed on the cylindrical case.

[0012] A drive unit according to one aspect of the present invention comprises a drive device that outputs rotational power, and a reducer that receives power from the drive device and decelerates the input rotation, the reducer comprising an input rotating body that rotates upon receiving power from the drive device, a reduction mechanism that decelerates the rotation of the input rotating body, and a cylindrical case that covers the outside of the reduction mechanism and rotates upon receiving the power reduced by the reduction mechanism, and the cylindrical case has an output arm integrally formed therewith that extends radially outward from the outer circumferential surface of the cylindrical case and transmits operating force to the outside.

[0013] A steering assist device according to one embodiment of the present invention comprises a drive unit that outputs rotational power, a reducer that receives power from the drive unit and decelerates the input rotation, and a steering mechanism that operates by receiving the power decelerated by the reducer, wherein the reducer comprises an input rotating body that rotates by receiving power from the drive unit, a reduction mechanism that decelerates the rotation of the input rotating body, and a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power decelerated by the reduction mechanism, and the cylindrical case has an output arm integrally formed therewith that extends radially outward from the outer circumferential surface of the cylindrical case and transmits an operating force to the steering mechanism. [Effects of the Invention]

[0014] In the above-mentioned reducer, the output arm extending radially outward from the outer peripheral surface of the cylindrical case is formed integrally with the cylindrical case, so that stable torque can be output to the outside through the output arm without increasing the size and weight of the entire device or the number of manufacturing steps. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram illustrating a general configuration of a steering assist device according to an embodiment. [Figure 2] FIG. 2 is a longitudinal sectional view of the reducer according to the first embodiment. [Figure 3] FIG. 4 is a cross-sectional view showing a modified example of the reducer of the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing another modified example of the reducer of the first embodiment. [Figure 5] FIG. 6 is a longitudinal sectional view of a reducer according to a second embodiment. [Figure 6] 6 is a view of the reducer of the second embodiment taken along the line VI in FIG. 5. [Figure 7] FIG. 10 is a side view of a reducer according to a second embodiment. [Figure 8] FIG. 10 is a longitudinal sectional view of a reducer according to a third embodiment. [Figure 9] FIG. 11 is a cross-sectional view showing a first modified example of the reducer of the third embodiment. [Figure 10] FIG. 11 is a cross-sectional view showing a second modified example of the reducer of the third embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing a third modified example of the reducer of the third embodiment. [Figure 12] FIG. 10 is a vertical cross-sectional view of a drive unit according to a fourth embodiment. [Figure 13] 13 is a view of the reducer of the fourth embodiment taken along the arrow XIII in FIG. 12. [Figure 14] 13 is a view showing a modified example of the reducer of the fourth embodiment, corresponding to a view taken along an arrow XIII in FIG. 12. [Figure 15] FIG. 11 is a vertical cross-sectional view of a drive unit according to a fifth embodiment. [Figure 16] FIG. 13 is a longitudinal sectional view of a drive unit according to a sixth embodiment. [Figure 17] 17 is a view of the reducer according to the sixth embodiment taken along the arrow XVII in FIG. 16. [Figure 18] FIG. 13 is a longitudinal sectional view of a drive unit according to a seventh embodiment. [Figure 19] FIG. 13 is a longitudinal sectional view of a drive unit according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Next, an embodiment of the present invention will be described with reference to the drawings.

[0017] <Steering assist device> FIG. 1 is a schematic diagram of a vehicle steering assist device 1 that employs a drive unit 10 according to this embodiment. The steering assist device 1 includes a steering wheel 2, a steering shaft 3, a drive unit 10 that also serves as a steering transmission section, and a steering mechanism 6 that is steered through the drive unit 10. The steering wheel 2 is located in front of the driver's seat of the vehicle and is rotated by the driver. The steering shaft 3 is integrally connected to the steering wheel 2 and rotates integrally therewith.

[0018] The drive unit 10 includes a motor 8, which is a drive device for steering assist, and a reducer 11 (111, 211, 311, 411, 511, 611, 711) that reduces the rotation of the motor 8 and transmits it to the steering mechanism 6. The drive unit 10 is connected to the lower end of the steering shaft 3. The steering torque transmitted from the steering wheel 2 to the steering shaft 3 is input to the input section of the reducer 11 via a gear mechanism (not shown). The input section of the reducer 11 combines the input steering torque with the assist torque generated by the motor 8 and transmits the combined torque to the reduction mechanism. Therefore, the combined steering torque and assist torque are reduced to a predetermined reduction ratio and output to the output side of the reducer 11 (the steering mechanism 6 side).

[0019] A torque sensor (not shown) is provided on the steering shaft 3. The torque detected by the torque sensor is input to a controller (not shown) for controlling the motor 8. The controller controls the output of the motor 8 based on the input signal from the torque sensor. The steering of the steering wheel 2 by the driver is assisted by the torque of the motor 8 controlled by the controller.

[0020] An output arm 27, which will be described later, is provided on the output side of the reducer 11. The tip of the output arm 27 is connected to the steering mechanism 6 of the vehicle. The steering mechanism 6 includes an operating arm 6b that receives an operating force from the output arm 27, and a tie rod 6a that steers the front wheels W of the vehicle by operating the operating arm 6b. The reducers 11, 111, 211, 311, 411, 511, 611, and 711 of the embodiments described below can be used in the steering assist device 1 shown in FIG.

[0021] First Embodiment FIG. 2 is a diagram showing a vertical cross section of the reducer 11 of the first embodiment. The reducer 11 comprises a base block 12 fixedly installed on the vehicle, a plurality of (e.g., three) crankshafts 13 (input rotating bodies) rotatably supported on the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate together with the two eccentric rotating portions 13b of each crankshaft 13, and a cylindrical case 15 rotatably supported on the outer peripheral surface of the base block 12 so as to cover the radial outside of the first oscillating gear 14A and the second oscillating gear 14B.

[0022] The base block 12 is formed in the shape of a short cylinder as a whole. For ease of explanation, the direction along the central axis o1 of the base block 12 will be referred to as the axial direction, and the radial direction from the central axis o1 will be referred to as the radial direction. Furthermore, with respect to the axial direction, the side facing the inside of the object will be referred to as the axial inner side, and the opposite side will be referred to as the axial outer side. These terms will also be used in the explanations of other embodiments.

[0023] The base block 12 includes a first base block 12A disposed at one end in the axial direction, and a second base block 12B disposed at the other end in the axial direction. The first base block 12A has a disk-shaped base plate 12Aa and a fixing flange 12Ab that bends axially outward from the outer peripheral edge of the base plate 12Aa in a crank shape and then projects radially outward. A case of the motor 8 is fastened and fixed to the fixing flange 12Ab. The second base block 12B has a disk-shaped base plate 12Ba with approximately the same outer diameter as the base plate 12Aa of the first base block 12A, and multiple connecting struts 12Bb that extend from the end face of the base plate 12Ba toward the first base block 12A. Multiple (e.g., three) connecting struts 12Bb are arranged on the end face of the base plate 12Ba on a concentric circle centered on the central axis o1.

[0024] The second base block 12B has end faces of connecting columns 12Bb butted against end faces of the base plate portion 12Aa of the first base block 12A, and each connecting column 12Bb is fastened and fixed to the first base block 12A with a bolt 16. Note that reference numeral 17 in Fig. 2 denotes a positioning pin for positioning the first base block 12A to each connecting column 12Bb before fastening with the bolt 16.

[0025] An axial gap is secured between the base plate portions 12Aa, 12Ba of the first base block 12A and the second base block 12B. A first oscillating gear 14A and a second oscillating gear 14B are disposed in this gap. A plurality of relief holes 18 are formed in the first oscillating gear 14A and the second oscillating gear 14B, through which the connecting struts 12Bb of the first base block 12A pass. The relief holes 18 are formed sufficiently larger than the outer surface shape of the connecting struts 12Bb so that the connecting struts 12Bb do not interfere with the oscillating rotation of the first oscillating gear 14A and the second oscillating gear 14B.

[0026] The cylindrical case 15 is disposed across the outer peripheral surface of the base plate portion 12Aa of the first base block 12A and the outer peripheral surface of the base plate portion 12Ba of the second base block 12B. Both axial edges of the cylindrical case 15 are rotatably supported via bearings 19 on the outer peripheries of the base plate portions 12Aa and 12Ba of the first base block 12A and the second base block 12B. Furthermore, a plurality of pin grooves 20 extending parallel to the central axis o1 of the first and second base blocks 12A and 12B are formed on the inner peripheral surface of the axial central region of the cylindrical case 15 (region facing the outer peripheral surfaces of the first oscillatory gear 14A and the second oscillatory gear 14B). A substantially cylindrical internally toothed pin 21 is rotatably received in each pin groove 20. The plurality of internally toothed pins 21 attached to the inner peripheral surface of the cylindrical case 15 face the outer peripheral surfaces of the first oscillatory gear 14A and the second oscillatory gear 14B.

[0027] The first oscillating gear 14A and the second oscillating gear 14B are formed with an outer diameter slightly smaller than the inner diameter of the cylindrical case 15. External teeth 14Aa, 14Ba are formed on the outer peripheral surfaces of the first oscillating gear 14A and the second oscillating gear 14B, respectively, and are in meshing contact with a plurality of internally toothed pins 21 arranged on the inner peripheral surface of the cylindrical case 15. The number of teeth of the external teeth 14Aa, 14Ba formed on the outer peripheral surfaces of the first oscillating gear 14A and the second oscillating gear 14B is set to be slightly less (for example, one less) than the number of internally toothed pins 21 (pin grooves 20).

[0028] The multiple crankshafts 13 are arranged on the same circumference centered on the central axis o1 of the first base block 12A and the second base block 12B. Each crankshaft 13 is rotatably supported by the first base block 12A and the second base block 12B via bearings 22. Each crankshaft 13 is formed with a pair of journal portions 13a spaced apart in the axial direction, and each journal portion 13a is supported by a bearing 22. The two eccentric rotation portions 13b described above are arranged between the pair of journal portions 13a of each crankshaft 13.

[0029] A gear mounting portion 13c is formed adjacent to the journal portion 13a at one axial end of the crankshaft 13 (the side where the motor 8 is disposed). The gear mounting portion 13c protrudes axially outward from the base plate portion 12Aa of the first base block 12A. A crank gear 24 that meshes with an output gear 23 on the motor 8 side is attached to the gear mounting portion 13c.

[0030] A gear of a gear mechanism (not shown) on the steering shaft 3 (see FIG. 1) meshes with the crank gear 24. Therefore, the operating force of the steering wheel 2 by the driver is input to the crankshaft 13 through the crank gear 24, and at the same time, the assist force from the motor 8 is also input to the crankshaft 13 through the crank gear 24.

[0031] Further, the first oscillating gear 14A and the second oscillating gear 14B are formed with support holes 25 through which the corresponding eccentric rotating portions 13b of the crankshaft 13 are inserted. The support hole 25 portions of the first oscillating gear 14A and the second oscillating gear 14B are supported by the corresponding eccentric rotating portions 13b of the crankshaft 13 via eccentric portion bearings 26 (cylindrical roller bearings).

[0032] When the multiple crankshafts 13 of the reducer 11 receive torque from the steering shaft 3 and the motor 8 and rotate in one direction, the eccentric rotation portions 13b of the crankshafts 13 revolve in the same direction at a predetermined radius, and accordingly the first oscillating gear 14A and the second oscillating gear 14B oscillate and rotate in the same direction at the same radius. At this time, the external teeth 14Aa, 14Ba of the first oscillating gear 14A and the second oscillating gear 14B come into contact with the multiple internal tooth pins 21 held on the inner periphery of the cylindrical case 15 so as to mesh with each other.

[0033] In the reducer 11, the number of teeth of each of the external teeth 14Aa, 14Ba of the first oscillating gear 14A and the second oscillating gear 14B is set to be slightly less than the number of internal tooth pins 21 on the cylindrical case 15 side, so that during one oscillating rotation of the first oscillating gear 14A and the second oscillating gear 14B, the external teeth 14Aa, 14Ba of the first oscillating gear 14A and the second oscillating gear 14B push and move the cylindrical case 15 in the same direction at a predetermined pitch. As a result, the rotation of the crankshaft 13 is reduced to a predetermined reduction ratio and output as rotation of the cylindrical case 15. In this embodiment, the crankshaft 13 constitutes an input rotating body of the reducer 11. The first oscillating gear 14A and the second oscillating gear 14B, together with the internal tooth pin 21 and the like, constitute a reduction mechanism in the reducer 11.

[0034] Here, the cylindrical case 15 has a case main body 15a that covers the radial outside of the reduction mechanism and is rotatably supported on the base block 12 by a bearing 19, and an output arm 27 that extends radially outward from the outer circumferential surface of the case main body 15a. In this embodiment, the output arm 27 extends radially outward from approximately the center position in the axial direction of the case main body 15a. The output arm 27 is formed integrally with the case main body 15a by casting or the like.

[0035] 2 denotes a sealing member that seals between the first base block 12A (substrate portion 12Aa) and the case main body 15a (substrate portion) and between the second base block 12B (substrate portion 12Ba) and the case main body 15a. The space surrounded by the cylindrical case 15 and the base block 12 and in which the speed reduction mechanism is disposed is filled with a lubricating liquid for lubricating mechanical operating parts such as the speed reduction mechanism.

[0036] As described above, in the reducer 11 of this embodiment, the output arm 27 extending radially outward from the outer peripheral surface of the cylindrical case 15 is formed integrally with the cylindrical case 15. Therefore, unlike when a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to the flange, it is possible to output a stable torque to the outside through the output arm 27 without increasing the size and weight of the entire reducer 11 or the number of manufacturing steps.

[0037] Furthermore, in the drive unit 10 employing the reducer 11 of this embodiment, the output side of the reducer 11 can be made lighter, so that the power consumption of the motor 8 can be reduced.

[0038] Furthermore, the steering assist device 1 that employs the drive unit 10 of this embodiment allows the output side of the reducer 11 to be made smaller and lighter, thereby increasing the freedom of vehicle layout and contributing to vehicle weight reduction.

[0039] 2, the output arm 27 extends radially from approximately the center position in the axial direction of the cylindrical case 15, but the output arm 27 may extend radially outward from one axial end of the cylindrical case 15, as in the modified example shown in Fig. 3. In the modified example shown in Fig. 3, the output arm 27 extends radially outward from the end adjacent to the fixing flange 12Ab that protrudes radially outward from the base plate portion 12Aa of the first base block 12A.

[0040] 4, the output arm 27 may extend radially outward from the other axial side of the cylindrical case 15 (the end opposite to the side where the fixed flange 12Ab is arranged). In this configuration, the output arm 27 extends radially outward from the end opposite to the protruding side of the fixing flange 12Ab, so the output arm 27 is less likely to interfere with the assembly work when assembling components such as the motor 8. Therefore, when this configuration is adopted, the assembly workability can be improved.

[0041] Second Embodiment In each embodiment described below, the same reference numerals will be used to designate parts common to the first embodiment. Fig. 5 is a diagram showing a vertical cross section of a reducer 111 of the second embodiment, Fig. 6 is a view of the reducer 111 taken along the line VI in Fig. 5, and Fig. 7 is a side view of the reducer 111. The reducer 111 of this embodiment includes a base block 12 fixed to the vehicle, multiple crankshafts 13 (input rotors) rotatably supported on the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshaft 13, and a cylindrical case 15 that covers the radial outside of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner peripheral surface of the cylindrical case 15, and an internally toothed pin 21 is held in the pin groove 20. The internally toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0042] The cylindrical case 15 has a case main body 15a that covers the radial outside of the reduction mechanism, and an output arm 27 that extends radially outward from the outer peripheral surface of one axial end of the case main body 15a (the side opposite to the side where the motor 8 is disposed). The output arm 27 is formed integrally with the case main body 15a by casting or the like. The output arm 27 is formed, for example, in the shape of a rectangular pillar.

[0043] Strain gauges 90 for detecting stress acting on the output arm 27 are attached to the four side surfaces of the output arm 27. The strain gauges 90 are electrically connected to the input section of a controller (not shown) and output a detection signal corresponding to the strain to the controller.

[0044] Furthermore, a rotation detection device (not shown) for detecting the rotation speed of the output arm 27 is attached to an appropriate position of the reducer 111, for example, between the base block 12 and the cylindrical case 15. The rotation detection device is electrically connected to an input section of a controller (not shown), and outputs a detection signal indicating the rotation speed of the output arm 27 to the controller.

[0045] The controller receives detection signals from the strain gauge 90 and the rotation detection device, calculates the average torque and average rotation speed acting on the output arm 27, and determines from the results whether the reducer 111 is approaching its service life limit. If the controller determines that the reducer 111 is approaching its service life limit, it notifies the user that it is time to replace the reducer 111 by turning on a warning display or the like.

[0046] As described above, in the reducer 111 of this embodiment, the output arm 27 extending radially outward from the outer peripheral surface of the cylindrical case 15 is formed integrally with the cylindrical case 15. Therefore, unlike when a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to the flange, it is possible to output a stable torque to the outside through the output arm 27 without increasing the size and weight of the entire reducer 111 or the number of manufacturing steps.

[0047] Furthermore, in the reducer 111 of this embodiment, a strain gauge 90 for detecting stress acting on the output arm 27 is attached to the output arm 27 extending radially outward from the outer circumferential surface of the cylindrical case 15. Therefore, by utilizing the detection value detected by the strain gauge 90, it is possible to accurately determine whether or not the reducer 111 is approaching its service limit. In particular, when the speed reducer 111 is provided with a rotation detection device together with the strain gauge 90, it is possible to more accurately determine whether the speed reducer 111 is approaching its endurance limit.

[0048] Other inventions that can be extracted from the second embodiment described above are listed below. (1) an input rotor (e.g., crankshaft 13) that rotates by receiving power from a drive device; a speed reduction mechanism (for example, a first oscillating gear 14A, a second oscillating gear 14B, and an internal tooth pin 21) that reduces the rotation speed of the input rotor; a cylindrical case (for example, cylindrical case 15) that covers the outside of the reduction mechanism and rotates by receiving power reduced by the reduction mechanism, An output arm (e.g., output arm 27) that extends radially outward from the outer circumferential surface of the cylindrical case and transmits an operating force to the outside is integrally formed with the cylindrical case, The output arm of the reducer is fitted with a strain gauge (for example, strain gauge 90) that detects stress acting on the output arm.

[0049] (2) a base block (e.g., base block 12); a crankshaft (e.g., crankshaft 13) having an eccentric rotation portion and rotatably supported on the base block, to which power is input from a drive device; an oscillating gear (for example, first and second oscillating gears 14A and 14B) having external teeth on an outer periphery thereof and oscillatingly rotating upon receiving an eccentric rotational force from the eccentric rotation portion; a cylindrical case (e.g., cylindrical case 15) having a different number of internal teeth than the external teeth, and which is rotatably supported on the base block and rotates while meshing with the external teeth; An output arm (e.g., output arm 27) that extends radially outward from the outer circumferential surface of the cylindrical case and transmits an operating force to the outside is integrally formed with the cylindrical case, The output arm of the reducer is fitted with a strain gauge (for example, strain gauge 90) that detects stress acting on the output arm.

[0050] (3) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the input rotation, The reducer is an input rotor that receives power from the drive device and rotates; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, an output arm extending radially outward from an outer circumferential surface of the cylindrical case and transmitting an operating force to the outside is integrally formed with the cylindrical case; A drive unit in which a strain gauge is attached to the output arm to detect stress acting on the output arm.

[0051] (4) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the speed of the input rotation; a steering mechanism that operates by receiving the power reduced by the reducer, The reducer is an input rotor that receives power from the drive device and rotates; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, an output arm extending radially outward from an outer circumferential surface of the cylindrical case and transmitting an operating force to the outside is integrally formed with the cylindrical case; A steering assist device in which a strain gauge is attached to the output arm to detect stress acting on the output arm.

[0052] Third Embodiment FIG. 8 is a diagram showing a vertical cross section of a reducer 211 according to the third embodiment. The reducer 211 includes a base block 12 fixed to the vehicle, a plurality of crankshafts 13 (input rotors) rotatably supported by the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshafts 13, and a cylindrical case 115 that covers the radial outside of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner peripheral surface of the cylindrical case 115, and an internally toothed pin 21 is held in the pin groove 20. The internally toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a reduction mechanism. The specific configurations of the crankshafts 13 and the reduction mechanism are the same as those in the first embodiment.

[0053] The base block 12 has a first base block 12A disposed at one axial end and a second base block 12B disposed at the other axial end. The second base block 12B has a connecting support 12Bb abutted against a base plate 12Aa of the first base block 12A, and in this state, the connecting support 12Bb is fixed to the base plate 12Aa with a bolt 16.

[0054] A bearing support surface 30 of a predetermined outer diameter is formed on the outer peripheral surface of the base plate portion 12Aa of the first base block 12A. A bearing 31 for rotatably supporting the cylindrical case 115 on the base block 12 is supported on the bearing support surface 30. A duplex angular bearing is used as this bearing 31. Hereinafter, the bearing 31 will be referred to as the "duplex angular bearing 31." The duplex angular bearing 31 of this embodiment is configured with two angular contact ball bearings with a contact angle arranged axially. The duplex angular bearing 31 can support radial loads and thrust loads between the base block 12 and the cylindrical case 115. Furthermore, on the outer peripheral surface of the base plate portion 12Aa, a seal support surface 32 having an outer diameter larger than that of the bearing support surface 30 is formed at a position axially outside the bearing support surface 30. An annular seal member 28 is interposed between this seal support surface 32 and the inner peripheral surface of the cylindrical case 115 to seal the gap between them.

[0055] When assembling the reducer 211, the bearing support surface 30 and the seal support surface 32 of the base plate portion 12Aa of the first base block 12A are inserted into the inner periphery of the cylindrical case 15. In this embodiment, the base plate portion 12Aa forms the insertion portion of the base block 12. The insertion portion of the base block 12, together with the input rotating body (crankshaft 13) and the reduction mechanism portion (first and second oscillating gears 14A, 14B, etc.), is inserted into the inside of the cylindrical case 115 from one axial end side of the cylindrical case 115. The duplex angular bearing 31 and the seal member 28 are interposed between the insertion portion and the cylindrical case 115. The seal member 28 seals the gap between the cylindrical case 115 and the insertion portion, at a position closer to the axial end side of the cylindrical case 115 than the duplex angular bearing 31.

[0056] A screw fastening portion 33 that can be fastened by a screw thread and a screw groove is provided on the outer peripheral surface of the end of the bearing support surface 30 of the base plate portion 12Aa opposite to the seal support surface 32, and on the inner peripheral surface of the axially inner inner ring 31ib of the duplex angular bearing 31. The two inner rings 31ia, 31ib of the duplex angular bearing 31 are provisionally locked to the base block 12 side (first base block 12A side) by abutting the axially outer inner ring 31ia against the step surface between the bearing support surface 30 and the seal support surface 32 and fastening the axially inner inner ring 31ib to the end of the bearing support surface 30 with the screw fastening portion 33.

[0057] Here, the cylindrical case 115 has a case main body 115a that covers the radial outside of the reduction mechanism, an output arm 27 that extends radially outward from the outer circumferential surface of one axial end side (the side where the motor 8 is disposed) of the case main body 115a, an end wall 36 that closes the other axial end side of the case main body 115a, and an auxiliary cylindrical part 34 that is fixed by welding to one axial end face of the case main body 115a. The output arm 27 and the end wall 36 are formed integrally with the case main body 115a by casting or the like.

[0058] The inner diameter of the auxiliary cylinder portion 34 is formed to be approximately the same as the inner diameter of the case main body portion 115a. A region 34a of the inner peripheral surface of the auxiliary cylinder portion 34, which is closer to the case main body portion 115a, and an outer peripheral surface of the axially outer outer ring 31oa of the duplex angular bearing 31, are provided with screw fastening portions 35 that can be fastened with threads and thread grooves. The two outer rings 31oa, 31ob of the duplex angular bearing 31 are provisionally locked to the cylindrical case 15 by abutting the axially inner outer ring 31ob against a stepped surface of the formed portion of the pin groove 20 of the case main body portion 115a and fixing the axially outer outer ring 31oa to the inner surface of the auxiliary cylinder portion 34 with the screw fastening portion 35. Furthermore, the outer peripheral surface of the seal member 28 abuts against a region 34b of the inner peripheral surface of the auxiliary cylinder portion 34 on the side away from the case main body portion 115a. In this embodiment, the region 34a (screw fastening portion 35) of the inner surface of the auxiliary tube portion 34 that is closer to the case main body portion 115a constitutes the outer ring locking portion, and the region 34b of the inner surface of the auxiliary tube portion 34 that is away from the case main body portion 115a constitutes the seal abutment portion. Furthermore, the space surrounded by the cylindrical case 115 and the base block 12, in which the reduction mechanism is disposed, is filled with a lubricating liquid for lubricating the mechanical operating parts such as the reduction mechanism.

[0059] When assembling the reducer 211, first, the first and second oscillating gears 14A, 14B and the crankshaft 13 are temporarily assembled to the first base block 12A and the second base block 12B, and in this state, the first base block 12A and the second base block 12B are joined together with the bolts 16. In this state, the inner rings 31ia, 31ib of the duplex angular bearing 31 are temporarily assembled to the outer peripheral surface of the base plate portion 12Aa of the first base block 12A as described above. On the other hand, the outer rings 31 oa and 31 ob of the duplex angular bearing 31 are temporarily assembled to the inner peripheral surface of the cylindrical case 115 as described above, and the seal member 28 is attached to the inner peripheral surface of the auxiliary cylindrical portion 34 in advance.

[0060] Next, in this state, a part of the base block 12 (the inserted portion of the second base block 12B and the first base block 12A) is inserted into the cylindrical case 115 from one axial end of the cylindrical case 115 together with the first and second oscillating gears 14A, 14B and the crankshaft 13. At this time, the duplex angular bearing 31 is combined, and the inner peripheral surface of the seal member 28 is brought into contact with the seal support surface 32 of the first base block 12A. Thereafter, the base block 12 is prevented from coming off from the cylindrical case 15 by a removal prevention means (not shown). Thereafter, lubricating liquid is filled into the space surrounded by the cylindrical case 115 and the base block 12. One axial end of the cylindrical case 115 is sealed from the base block 12 by a seal member 28, and the other axial end of the cylindrical case 115 is sealed by an end wall 36.

[0061] As described above, in the reducer 211 of this embodiment, the output arm 27 extending radially outward from the outer peripheral surface of the cylindrical case 115 is formed integrally with the cylindrical case 115. Therefore, unlike when a fixing flange is provided on the cylindrical case 115 and a separate output arm is bolted to the flange, it is possible to output a stable torque to the outside through the output arm 27 without increasing the size and weight of the entire reducer 111 or the number of manufacturing steps.

[0062] Furthermore, in the reducer 211 of this embodiment, the other axial end of the cylindrical case 115 is completely closed by the end wall 36 that is integral with the cylindrical case 115. Therefore, it is possible to prevent leakage of lubricating liquid from the other axial end of the cylindrical case 115 without disposing a seal member between the inner circumferential surface of the other axial end of the cylindrical case 115 and the base block 12.

[0063] Furthermore, in the reducer 211 of this embodiment, a combination angular bearing 31 is disposed between the insertion portion of the base block 12 and the cylindrical case 115, and a seal member 28 is disposed closer to one axial end of the cylindrical case 115 than the combination angular bearing 31. Therefore, when assembling the reducer 211, a portion of the base block 12 can be easily disposed inside the cylindrical case 115 from one end side of the cylindrical case 115 together with the reduction mechanism, the crankshaft 13 (input rotating body), etc., and the number of parts of the seal member 28 used can be reduced.

[0064] Furthermore, in the reducer 211 of this embodiment, the outer ring locking portion and the seal abutment surface are formed in the auxiliary cylinder portion 34, which is a separate part from the case main body 115a of the cylindrical case 115, so that the auxiliary cylinder portion 34, which is a small part, can be attached to the case main body 115a after being machined with high precision. Therefore, when the reducer 211 of this embodiment is used, the cylindrical case 115 can be manufactured with high precision and easily.

[0065] FIG. 9 is a cross-sectional view showing a first modified example of the reducer 211 of this embodiment. 5, the auxiliary cylindrical portion 34 is fixed by welding to the axial end face of the case main body 115a of the cylindrical case 115, but in the first modified example, a fixing flange 34Aa extending radially outward is formed integrally with the auxiliary cylindrical portion 34A, and the fixing flange 34Aa portion is joined to the axial end face of the case main body 115a by bolts 37. The auxiliary cylindrical portion 34A and the outer ring 31oa of the duplex angular bearing 31 are fixed by a screw fastening portion 35.

[0066] FIG. 10 is a cross-sectional view showing a second modified example of the reducer 211 of this embodiment. The auxiliary cylinder portion 34A of the second modified example has a fixing flange 34Aa fixed to the case main body 115a with bolts 37, as in the first modified example, but the outer ring locking portion of the auxiliary cylinder portion 34A is configured by a locking protrusion 34Ab rather than a screw fastening portion 35. The locking protrusion 34Ab protrudes radially inward from the inner peripheral surface of the auxiliary cylinder portion 34A and abuts against the axially outer end face of the outer ring 31oa of the angular bearing 31. This prevents the outer ring 31oa of the angular bearing 31 from coming loose.

[0067] FIG. 11 is a cross-sectional view showing a third modified example of the reducer 211 of this embodiment. In the third modified example, instead of providing a separate auxiliary cylindrical portion 34, one axial end side of the case main body 115a of the cylindrical case 115 extends toward the fixed flange 12Ab of the first base block 12A. Outer rings 31oa, 31ob of the angular bearing 31 are disposed on the inner circumferential surface of the portion of the case main body 115a that extends toward the one axial end side. The outer ring 31oa on the axial outer side is prevented from coming off by a retaining ring 38 that is fixed to the inner circumferential surface of the case main body 115a.

[0068] Other inventions that can be extracted from the third embodiment described above are listed below. (1) a base block (e.g., base block 12); an input rotor (e.g., crankshaft 13) that is rotatably supported on the base block and rotates by receiving power from a drive device (e.g., motor 8); a speed reduction mechanism (for example, a first oscillating gear 14A, a second oscillating gear 14B, and an internal tooth pin 21) that reduces the rotation speed of the input rotor; a cylindrical case (for example, cylindrical case 115) that covers the outside of the reduction mechanism and rotates by receiving power reduced by the reduction mechanism, the base block has an insertion portion (for example, a base plate portion 12Aa) that is inserted into the cylindrical case from one end side in the axial direction of the cylindrical case together with the input rotor and the reduction mechanism portion, Between the insertion portion and the cylindrical case, A combined angular bearing (for example, combined angular bearing 31), a seal member (e.g., seal member 28) that seals the gap between the cylindrical case and the insertion portion is disposed closer to one end of the cylindrical case in the axial direction than the combined angular bearing; The cylindrical case has an end wall (for example, end wall 36) that closes the other end in the axial direction formed integrally with the reducer.

[0069] (2) The cylindrical case is a case body (for example, case body 115a) that accommodates the speed reduction mechanism therein; an auxiliary cylinder portion (e.g., auxiliary cylinder portion 34) fixed to one axial end of the case main body portion, The reducer described in (1) has an outer ring locking portion (e.g., a screw-fastening portion 35) that locks the outer ring of the combined angular bearing and a seal abutment portion (e.g., a seal support surface 32) that abuts against the seal member disposed on the inner peripheral surface of the auxiliary cylindrical portion.

[0070] (3) a base block (e.g., base block 12); a crankshaft (e.g., crankshaft 13) having an eccentric rotation portion and rotatably supported on the base block, to which power is input from a drive device (e.g., motor 8); an oscillating gear (for example, a first oscillating gear 14A, a second oscillating gear 14B) having external teeth on an outer periphery thereof and oscillatingly rotating upon receiving an eccentric rotational force from the eccentric rotation portion; a cylindrical case (e.g., cylindrical case 15) having internal teeth (e.g., internal tooth pins 21) with a number of teeth different from that of the external teeth, and which is rotatably supported on the base block and rotates while meshing with the external teeth; the base block has an insertion portion (for example, a base plate portion 12Aa) that is inserted into the cylindrical case from one end side in the axial direction of the cylindrical case together with the crankshaft and the oscillating gear, Between the insertion portion and the cylindrical case, A combined angular bearing (for example, combined angular bearing 31), a seal member (e.g., seal member 28) that seals the gap between the cylindrical case and the insertion portion is disposed closer to one end of the cylindrical case in the axial direction than the combined angular bearing; The cylindrical case has an end wall (for example, end wall 36) that closes the other end in the axial direction formed integrally with the reducer.

[0071] (4) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the input rotation, The reducer is A base block and an input rotor that receives power from the drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, the base block, together with the input rotor and the reduction mechanism, has an insertion portion that is inserted into the cylindrical case from one axial end side of the cylindrical case, Between the insertion portion and the cylindrical case, A combined angular contact bearing, a seal member that seals the gap between the cylindrical case and the insertion portion, the seal member being disposed closer to one end of the cylindrical case in the axial direction than the combined angular bearing; The drive unit has an end wall integrally formed with the cylindrical case that closes the other end in the axial direction.

[0072] (5) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the speed of the input rotation; a steering mechanism that operates by receiving the power reduced by the reducer, The reducer is A base block and an input rotor that receives power from the drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, the base block, together with the input rotor and the reduction mechanism, has an insertion portion that is inserted into the cylindrical case from one axial end side of the cylindrical case, Between the insertion portion and the cylindrical case, A combined angular contact bearing, a seal member that seals the gap between the cylindrical case and the insertion portion, the seal member being disposed closer to one end of the cylindrical case in the axial direction than the combined angular bearing; The steering assist device has an end wall integrally formed with the cylindrical case that closes the other end in the axial direction.

[0073] <Fourth embodiment> 12 is a view showing a vertical cross section of a drive unit 10 employing a reducer 311 according to a fourth embodiment. FIG. 13 is a view of the reducer 311 as seen from the arrow XIII in FIG. The reducer 311 of this embodiment includes a base block 12 fixed to the vehicle, multiple crankshafts 13 (input rotors) rotatably supported on the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radial outside of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner peripheral surface of the cylindrical case 15, and an internally toothed pin 21 is held in the pin groove 20. The internally toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0074] The base block 12 has a first base block 12A disposed at one axial end and a second base block 12B disposed at the other axial end. The second base block 12B has connecting struts 12Bb abutting against the base plate portion 12Aa of the first base block 12A, and in this state, the connecting struts 12Bb are fixed to the base plate portion 12Aa with bolts 16. A fixing flange 12Ab extending radially outward from the base plate portion 12Aa of the first base block 12A has bolt insertion holes 40 formed therethrough in the axial direction. Bolts for fixing to the vehicle body are inserted into the bolt insertion holes 40.

[0075] The cylindrical case 15 has a case main body 15a that covers the radial outside of the reduction mechanism, and an output arm 27 that extends radially outward from the outer peripheral surface of one axial end of the case main body 15a (the side opposite to the side where the motor 8 is disposed). The case main body 15a is rotatably supported via bearings 19 on the outer peripheral surfaces of a base plate portion 12Aa of the first base block 12A and a base plate portion 12Ba of the second base block 12B. The output arm 27 is formed integrally with the case main body 15a by casting or the like. The output arm 27 is formed, for example, in the shape of a rectangular pillar.

[0076] Furthermore, a seal member 28 is disposed between the outer peripheral surface of the substrate portion 12Aa of the first base block 12A and the inner peripheral surface of one axial end of the case body 15a, at a position axially outside the bearing 19 at one end, for sealing the gap between the substrate portion 12Aa and the case body 15a. Similarly, a seal member 28 is disposed between the outer peripheral surface of the substrate portion 12Ba of the second base block 12B and the inner peripheral surface of the other axial end of the case body 15a, at a position axially outside the bearing 19 at the other end, for sealing the gap between the substrate portion 12Ba and the cylindrical case 15. The space enclosed by the cylindrical case 15 and the base block 12 is filled with a lubricating liquid for lubricating mechanical operating parts such as a reduction gear mechanism.

[0077] An end flange 12Bc is integrally formed on the axially outer end of the end wall 12Bb of the second base block 12B so as to protrude radially outward. The end flange 12Bc is disposed so as to cover the axially outer region of the seal member 28 between the base plate portion 12Ba and the cylindrical case 15. A rotation detection device 41 is attached to the end flange 12Bc to detect the relative rotational position and relative rotational speed between the base block 12 and the cylindrical case 15.

[0078] The rotation detector 41 includes a detection target 42 attached to the other axial end surface of the cylindrical case 15 and a target detector 43 attached to the end flange 12Bc on the second base block 12B side. The target detector 43 outputs a signal to a controller (not shown) in response to changes in the detection status of the detection target 42 due to relative rotation between the base block 12 and the cylindrical case 15. The rotation detector 41 may be, for example, a magnetic detector or an optical detector. The target detector 43 of the rotation detector 41 extends radially outward so that a detection surface 43a faces the detection target 42 across a small gap. The detection surface 43a faces the detection target 42 in the axial direction. In this embodiment, the detection target 42 is attached to the end face on the other axial end side of the cylindrical case 15, and the target detection unit 43 is attached to the end flange 12Bc (substrate portion 12Ba), but it is also possible to attach the target detection unit 43 to the axial end face of the cylindrical case 15 and attach the detection target 42 to the end flange 12Bc.

[0079] The signal input from the rotation detection device 41 to the controller can be used, for example, when the controller detects and takes action when the output of the assist signal (drive signal) to the motor 8 has stopped for some reason, or when correcting a discrepancy between the target output and the actual rotation of the motor 8. When the controller detects that the output of the assist signal (drive signal) to the motor 8 has stopped, the controller, for example, cancels the reaction force of the motor 8 acting on the reducer 211. This makes it possible to prevent the reaction force of the motor 8 from interfering with the driver's manual steering operation.

[0080] As described above, in the reducer 311 of this embodiment, the output arm 27 extending radially outward from the outer peripheral surface of the cylindrical case 15 is formed integrally with the cylindrical case 15. Therefore, unlike when a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to the flange, it is possible to output a stable torque to the outside through the output arm 27 without increasing the size and weight of the entire reducer 211 or the number of manufacturing steps.

[0081] Furthermore, the reducer 311 of this embodiment is provided with a rotation detection device 41 that detects the relative rotation between the base block 12 and the cylindrical case 15, so that rotation information on the output side of the motor 8 can be obtained at the end of the reducer 311 where there is more space. This allows the rotation information on the output side of the motor 8 to be effectively used by the controller without increasing the size of the motor 8.

[0082] Furthermore, in the reducer 311 of this embodiment, the detection target 42 of the rotation detection device 41 is disposed on the axial end face of the cylindrical case 15, and the target detection unit 43 is disposed on the end face of the second base block 12B so that the detection surface 43a faces the detection target 42. Therefore, when this configuration is adopted, the rotation detection device 41 can be easily installed on the reducer 311 from the outside, and maintenance of the rotation detection device 41 can also be easily performed.

[0083] Furthermore, in the reducer 311 of this embodiment, an end flange 12Bc is provided on the outer periphery of the substrate portion 12Ba of the second base block 12B so as to cover the gap between the substrate portion 12Ba and the cylindrical case 15, and the target detection portion 43 of the rotation detection device 41 is attached to the end flange 12Bc. Therefore, the end flange 12Bc can prevent foreign matter from entering the gap between the substrate portion 12Ba and the cylindrical case 15 (the portion in the vicinity of the seal member 28), and the detection surface 43a of the target detection portion 43 can be brought closer to the detection target 42 on the cylindrical case 15 side.

[0084] FIG. 14 is a view similar to FIG. 13 showing a modified example of the reducer 311 of this embodiment. 12 and 13, the detection target 42 of the rotation detection device 41 is arranged in an annular shape on the axial end surface of the cylindrical case 15, but in the modified example shown in Fig. 14, a semicircular detection target 42A is arranged on the axial end surface of the cylindrical case 15. If the rotation range of the cylindrical case 15 actually used in the reducer 311 (the rotation range of the output arm 27) is narrow, the detection target 42A does not need to be a complete annular shape. For this reason, the detection target 42A may be semicircular as in the modified example shown in Fig. 14, or may be an arc shape other than a semicircle.

[0085] <Fig. 5 embodiment> FIG. 15 is a diagram showing a vertical cross section of a drive unit 10 employing a reducer 411 according to the fifth embodiment. The basic configuration of the reducer 411 of this embodiment is almost the same as that of the reducer 311 of the fourth embodiment, except for the installation section of the rotation detection device 41. Therefore, in the following, the same reference numerals will be used to designate parts common to the reducer 311 of the fourth embodiment, and some overlapping explanations will be omitted.

[0086] The reducer 411 is formed so that an axial end of the substrate portion 12Ba of the second base block 12B protrudes axially outward beyond the other axial end of the cylindrical case 15. A target detection portion 43 of the rotation detection device 41 is attached to the outer peripheral surface of the end of the substrate portion 12Ba protruding from the cylindrical case 15.

[0087] A cylindrical cover member 45 with a bottom is attached to the other axial surface of the cylindrical case 15, covering the outer peripheral surface and end face of the protruding portion of the substrate portion 12Ba in a non-contact manner. A detection target 42B is attached to the inner peripheral surface of the peripheral wall of the cover member 45. The detection target 42B is arranged in a semicircular shape along the inner peripheral surface of the peripheral wall of the cover member 45. However, the detection target 42B may be arranged in an arc shape other than a semicircle, or in a ring shape. The target detector 43 attached to the outer peripheral surface of the substrate portion 12Ba has a detection surface 43a facing the detection target 42B with a predetermined gap therebetween.

[0088] In this embodiment, the target detection unit 43 is attached to the outer peripheral surface of the substrate portion 12Ba, and the detection target 42B is attached to the inner peripheral surface of the cover member 45, but it is also possible to attach the target detection unit 43 to the inner peripheral surface of the cover member 45, and the detection target 42B to the outer peripheral surface of the substrate portion 12Ba. Furthermore, it is also possible to attach one of the target detector 43 and the detection target 42B to the end surface of the substrate 12Ba, and attach the other to the inner end surface of the cover member 45.

[0089] In this embodiment, too, the signal input to the controller from the rotation detection device 41 can be used to detect and deal with a situation in which the output of the assist signal (drive signal) to the motor 8 has stopped for some reason, or to correct the discrepancy between the output target and the actual rotation of the motor 8.

[0090] As described above, the reducer 411 of this embodiment has the same basic configuration as the reducer 311 of the fourth embodiment, and therefore can obtain the same basic effects as the reducer 311 of the fourth embodiment. However, in the reducer 411 of this embodiment, a cylindrical cover member 45 with a bottom is attached to the other axial surface of the cylindrical case 15, and the rotation detection device 41 is disposed between the outer peripheral surface of the substrate portion 12Ba on the base block 12 side and the inner peripheral surface of the cover member 45. Therefore, the cover member 45 prevents foreign matter such as iron powder from entering the periphery of the rotation detection device 41, thereby suppressing a decrease in the detection accuracy of the rotation detection device 41. Furthermore, in this embodiment, the cover member 45 can prevent foreign matter from entering the vicinity of the seal member 28.

[0091] Other inventions that can be extracted from the above fourth and fifth embodiments are listed below. (1) a base block (e.g., base block 12); an input rotor (e.g., crankshaft 13) that is rotatably supported on the base block and rotates by receiving power from a drive device (e.g., motor 8); a speed reduction mechanism (for example, a first oscillating gear 14A, a second oscillating gear 14B, and an internal tooth pin 21) that reduces the rotation speed of the input rotor; a cylindrical case (for example, cylindrical case 115) that covers the outside of the reduction mechanism and rotates by receiving power reduced by the reduction mechanism; a rotation detection device (for example, rotation detection device 41) that detects the relative rotation state between the base block and the cylindrical case;

[0092] (2) The rotation detection device is a detection target (e.g., detection target 42, 42A) installed on one of the axial end surface of the cylindrical case and the axial end surface of the base block; a target detector (for example, a target detector 43) installed on the other of the axial end surface of the cylindrical case and the axial end surface of the base block; The reducer according to (1), wherein a detection surface (for example, detection surface 43a) of the target detection unit is disposed so as to face the detection target.

[0093] (3) A cover member (e.g., cover member 45) is attached to the cylindrical case to cover the axial end of the cylindrical case, The rotation detection device is a detection target (for example, detection target 42B) installed on either one of the cover member and the axial end of the base block; a target detector (for example, a target detector 43) installed on the other of the cover member and the axial end of the base block; The reducer according to (1), wherein the detection surface of the target detection unit is disposed so as to face the detection target.

[0094] (4) a base block (e.g., base block 12); a crankshaft (e.g., crankshaft 13) having an eccentric rotation portion and rotatably supported on the base block, to which power is input from a drive device (e.g., motor 8); an oscillating gear (for example, a first oscillating gear 14A, a second oscillating gear 14B) having external teeth on an outer periphery thereof and oscillatingly rotating upon receiving an eccentric rotational force from the eccentric rotation portion; a cylindrical case (e.g., cylindrical case 15) having internal teeth (e.g., internal tooth pins 21) with a different number of teeth than the external teeth, which rotates while meshing with the external teeth while being rotatably supported on the base block; a rotation detection device (for example, rotation detection device 41) that detects the relative rotation state between the base block and the cylindrical case;

[0095] (5) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the input rotation, The reducer is A base block and an input rotor that receives power from a drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism; a rotation detection device that detects the relative rotation state between the base block and the cylindrical case. (6) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the speed of the input rotation; a steering mechanism that operates by receiving the power reduced by the reducer, The reducer is an input rotor that receives power from a drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism; a rotation detection device that detects the relative rotation state between the base block and the cylindrical case.

[0096] Sixth Embodiment FIG. 16 is a view showing a vertical cross section of a drive unit 10 employing a reducer 511 according to a sixth embodiment, and FIG. 17 is a view of the reducer 511 as seen from the arrow XII in FIG. The reducer 511 of this embodiment includes a base block 12 fixed to the vehicle, multiple crankshafts 13 (input rotors) rotatably supported on the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radial outside of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner peripheral surface of the cylindrical case 15, and an internally toothed pin 21 is held in the pin groove 20. The internally toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0097] The base block 12 has a first base block 12A disposed at one axial end and a second base block 12B disposed at the other axial end. The second base block 12B has a connecting strut 12Bb abutted against a base plate portion 12Aa of the first base block 12A, and in this state, the connecting strut 12Bb is fixed to the base plate portion 12Aa with a bolt 16. A fixing flange 12Ab extending radially outward from the base plate portion 12Aa of the first base block 12A is formed with a bolt insertion hole 40 penetrating in the axial direction. A bolt for fixing to the vehicle body (not shown) is inserted into the bolt insertion hole 40.

[0098] The cylindrical case 15 has a case main body 15a that covers the radial outside of the reduction mechanism, and an output arm 27 that extends radially outward from the outer peripheral surface of one axial end of the case main body 15a (the side opposite to the side where the motor 8 is disposed). The case main body 15a is rotatably supported via bearings 19 on the outer peripheral surfaces of a base plate portion 12Aa of the first base block 12A and a base plate portion 12Ba of the second base block 12B. The output arm 27 is formed integrally with the case main body 15a by casting or the like. The output arm 27 is formed, for example, in the shape of a rectangular pillar.

[0099] A seal member 28 is disposed between the outer peripheral surface of the substrate portion 12Aa of the first base block 12A and the inner peripheral surface of one axial end of the case body 15a, at a position axially outside the bearing 19 at one end, for sealing the gap between the substrate portion 12Aa and the case body 15a. Similarly, a seal member 28 is disposed between the outer peripheral surface of the substrate portion 12Ba of the second base block 12B and the inner peripheral surface of the other axial end of the case body 15a, at a position axially outside the bearing 19 at the other end, for sealing the gap between the substrate portion 12Ba and the cylindrical case 15. The space enclosed by the cylindrical case 15 and the base block 12 is filled with lubricating liquid for lubricating mechanical operating parts such as a reduction gear mechanism.

[0100] An end flange 12Bc is integrally formed on the axially outer end of the end wall 12Bb of the second base block 12B so as to protrude radially outward. The end flange 12Bc is disposed so as to cover the axially outer region of the seal member 28 between the base plate portion 12Ba and the cylindrical case 15. A plurality of heat dissipation fins 50 are integrally formed on the axially outer end surface of the base plate portion 12Ba including the end flange 12Bc.

[0101] There are two types of heat dissipation fins 50. One is an annular fin 50a that protrudes axially outward from the end face of the substrate portion 12Ba, and the other is a radiating fin 50b that protrudes radially from the outer periphery of the end of the substrate portion 12Ba. The annular fin 50a is a continuous fin in an annular shape centered on the central axis o1 of the substrate portion 12Ba, and multiple fins are arranged in a radially offset manner (with different diameters). These heat dissipation fins 50 can dissipate heat transferred from inside the reducer 511 to the substrate portion 12Ba into the surrounding air. The radiating fins 50b and the outermost annular fin 50a are arranged at approximately the same radial position as the holding position of the internal tooth pins 21 inside the cylindrical case 15.

[0102] As described above, in the reducer 511 of this embodiment, the output arm 27 extending radially outward from the outer peripheral surface of the cylindrical case 15 is formed integrally with the cylindrical case 15. Therefore, unlike when a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to the flange, it is possible to output a stable torque to the outside through the output arm 27 without increasing the size and weight of the entire reducer 211 or the number of manufacturing steps.

[0103] Furthermore, in the reducer 511 of this embodiment, a plurality of heat dissipation fins 50 are formed on the portion of the base block 12 that is exposed to the outside of the cylindrical case 15 (the end surface of the substrate portion 12Ba). This allows heat generated inside the reducer 511 by the operation of the reduction mechanism, etc., to be efficiently dissipated to the surroundings. Therefore, when this configuration is adopted, the temperature rise of the base block 12 and the cylindrical case 15 can be suppressed, and the rotation speed of the mechanical operating part in the reducer 511 can be increased accordingly. The heat dissipation fins 50 can also be formed on the outer peripheral surface of the cylindrical case 15 .

[0104] Other inventions that can be extracted from the sixth embodiment are listed below. (1) a base block; an input rotor that receives power from a drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, The reducer has heat dissipation fins formed on a portion of the base block that is exposed to the outside of the cylindrical case.

[0105] (2) a base block; a crankshaft having an eccentric rotation portion, rotatably supported by the base block, and receiving power from a drive device; an oscillating gear having external teeth on its outer periphery and adapted to oscillate and rotate by receiving an eccentric rotational force from the eccentric rotation portion; a cylindrical case having a number of internal teeth different from that of the external teeth, the cylindrical case being rotatably supported by the base block and rotating while meshing with the external teeth, The reducer has heat dissipation fins formed on a portion of the base block that is exposed to the outside of the cylindrical case.

[0106] (3) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the input rotation, The reducer is A base block and an input rotor that receives power from a drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, The drive unit has heat dissipation fins formed on a portion of the base block that is exposed to the outside of the cylindrical case.

[0107] (4) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the speed of the input rotation; a steering mechanism that operates by receiving the power reduced by the reducer, The reducer is A base block and an input rotor that receives power from a drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, A steering assist device in which heat dissipation fins are formed on a portion of the base block that is exposed to the outside of the cylindrical case.

[0108] Seventh Embodiment FIG. 18 is a view showing a vertical cross section of a drive unit 10 employing a reducer 611 according to the seventh embodiment. The reducer 611 of this embodiment includes a base block 12 fixed to the vehicle, multiple crankshafts 13 (input rotors) rotatably supported on the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radial outside of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner peripheral surface of the cylindrical case 15, and an internally toothed pin 21 is held in the pin groove 20. The internally toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0109] The base block 12 has a first base block 12A disposed at one axial end and a second base block 12B disposed at the other axial end. The second base block 12B has a connecting strut 12Bb abutted against a base plate portion 12Aa of the first base block 12A, and in this state, the connecting strut 12Bb is fixed to the base plate portion 12Aa with a bolt 16. A fixing flange 12Ab extending radially outward from the base plate portion 12Aa of the first base block 12A is formed with a bolt insertion hole 40 penetrating in the axial direction. A bolt for fixing to the vehicle body (not shown) is inserted into the bolt insertion hole 40.

[0110] The cylindrical case 15 has a case main body 15a that covers the radial outside of the reduction mechanism, and an output arm 27 that extends radially outward from the outer peripheral surface of one axial end of the case main body 15a (the side opposite to the side where the motor 8 is disposed). The case main body 15a is rotatably supported via bearings 19 on the outer peripheral surfaces of a base plate portion 12Aa of the first base block 12A and a base plate portion 12Ba of the second base block 12B. The output arm 27 is formed integrally with the case main body 15a by casting or the like. The output arm 27 is formed, for example, in the shape of a rectangular pillar.

[0111] A seal member 28 is disposed between the outer peripheral surface of the substrate portion 12Aa of the first base block 12A and the inner peripheral surface of one axial end of the case body 15a, at a position axially outside the bearing 19 at one end, for sealing the gap between the substrate portion 12Aa and the case body 15a. Similarly, a seal member 28 is disposed between the outer peripheral surface of the substrate portion 12Ba of the second base block 12B and the inner peripheral surface of the other axial end of the case body 15a, at a position axially outside the bearing 19 at the other end, for sealing the gap between the substrate portion 12Ba and the cylindrical case 15. The space enclosed by the cylindrical case 15 and the base block 12 is filled with lubricating liquid for lubricating mechanical operating parts such as a reduction gear mechanism.

[0112] The multiple crankshafts 13, which are output rotors, are arranged on the same circumference centered on the central axis o1 of the first base block 12A and the second base block 12B. Each crankshaft 13 is rotatably supported by the base plate portions 12Aa, 12Ba of the first base block 12A and the second base block 12B via bearings 22. Each crankshaft 13 is formed with a pair of journal portions 13a spaced apart in the axial direction, and each journal portion 13a is supported by a bearing 22. Two eccentric rotation portions 13b are arranged between the pair of journal portions 13a of each crankshaft 13. In this embodiment, a tapered roller bearing is used as bearing 22. Bearing 22 is assembled in support holes 47 of base plate portions 12Aa, 12Ba so that rollers that contact the inner and outer rings are inclined radially outward toward eccentric rotation portion 13b of crankshaft 13.

[0113] A gear mounting portion 13c is formed adjacent to the journal portion 13a at one axial end of the crankshaft 13 (the side where the motor 8 is disposed). The gear mounting portion 13c protrudes axially outward from a support hole 47 in the base plate portion 12Aa on the first base block 12A side. A crank gear 24 is attached to the gear mounting portion 13c. The crank gear 24 meshes with the output gear 23 on the motor 8 side and with a gear of a gear mechanism (not shown) on the steering shaft 3 (see FIG. 1).

[0114] A metal powder detection sensor 48 is attached to the support hole 47 of the base plate portion 12Aa at a position adjacent to the support portion of the bearing 22 on the axial outer side (motor 8 side) to detect metal powder mixed in the lubricating liquid in the reducer 711. The metal powder detection sensor 48 is attached to the side of the support hole 47 that is separated from the eccentric rotation portion 13b across the bearing 22, and is disposed in the space between the attachment surface on the support hole 47 side and the outer peripheral surface of the journal portion 13a on the crankshaft 13 side. The metal powder detection sensor 48 is fixed to the base plate portion 12Aa by press-fitting into the support hole 47, fastening with screws, or the like.

[0115] The metal powder detection sensor 48 may be, for example, a sensor in which an iron powder attracting portion using a permanent magnet is provided in a gap 48b provided in a sensor block 48a through which the lubricating liquid can flow, and the amount of iron powder attracted by the magnetic force of the permanent magnet is detected from a change in electrical resistance in the circuit. Note that the structure of the metal powder detection sensor 48 is not limited to this, as long as it can detect the amount of iron powder in the lubricating liquid.

[0116] The metal powder detection sensor 48 is electrically connected to an input unit of a controller (not shown). Based on the detection signal from the metal powder detection sensor 48, the controller determines whether the amount of metal powder mixed in the lubricating liquid in the reducer 711 is equal to or greater than a specified amount. If it is determined that the amount of metal powder mixed in is equal to or greater than the specified amount, the controller notifies the user that it is time to perform maintenance, such as changing the lubricating liquid, by turning on a warning display or the like.

[0117] As described above, in the reducer 711 of this embodiment, the output arm 27 extending radially outward from the outer peripheral surface of the cylindrical case 15 is formed integrally with the cylindrical case 15. Therefore, unlike when a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to the flange, it is possible to output a stable torque to the outside through the output arm 27 without increasing the size and weight of the entire reducer 711 or the number of manufacturing steps.

[0118] Furthermore, in the reducer 711 of this embodiment, the metal powder detection sensor 48 for detecting metal powder mixed in the lubricating liquid is disposed at a position axially separated from the reduction mechanism (first oscillating gear 14A and second oscillating gear 14B). Therefore, the amount of metal powder mixed in the lubricating liquid can be detected in a region away from the region where the lubricating liquid is significantly agitated by the operation of the reduction mechanism. When the reducer 711 of this embodiment is employed, the problem of being unable to accurately detect the amount of mixed metal powder due to the lubricating liquid being significantly agitated by the operation of the reduction mechanism can be resolved. Furthermore, when the reducer 711 of this embodiment is employed, the amount of mixed metal powder can be accurately detected even if the agitation state of the lubricating liquid by the reduction mechanism changes due to differences in the specifications of the reducer 711.

[0119] In particular, in the reducer 711 of this embodiment, the metal powder detection sensor 48 is positioned near the journal portion 13a of the crankshaft 13, so it is less susceptible to the agitation of the lubricating liquid caused by the operation of the eccentric rotating portion 13b of the crankshaft 13.

[0120] Furthermore, in the reducer 711 of this embodiment, the metal powder detection sensor 48 is fixed inside the support hole 47 of the base plate portion 12Aa that supports the journal portion 13a. Therefore, there is no need to provide a fixing flange or the like for attaching the metal powder detection sensor 48 to the base plate portion 12Aa side of the base block 12. Therefore, when the reducer 711 of this embodiment is used, the structure can be simplified and manufacturing can be facilitated.

[0121] Other inventions that can be extracted from the seventh embodiment are listed below. (1) a base block (e.g., base block 12); an input rotor (e.g., crankshaft 13) that is rotatably supported on the base block and rotates by receiving power from a drive device (e.g., motor 8); a speed reduction mechanism (for example, a first oscillating gear 14A, a second oscillating gear 14B, and an internal tooth pin 21) that reduces the rotation speed of the input rotor; a cylindrical case (for example, cylindrical case 115) that covers the outside of the reduction mechanism and rotates by receiving power reduced by the reduction mechanism; a metal powder detection sensor (e.g., metal powder detection sensor 48) that detects metal powder in the lubricating liquid filled in the space surrounded by the cylindrical case and the base block; The metal powder detection sensor is a reducer that is arranged near a bearing portion (for example, journal portion 13a) of the input rotor that is arranged at a position axially separated from the reduction mechanism portion. (2) a base block (e.g., base block 12); a crankshaft (e.g., crankshaft 13) having an eccentric rotation portion and rotatably supported on the base block, to which power is input from a drive device (e.g., motor 8); an oscillating gear (for example, a first oscillating gear 14A, a second oscillating gear 14B) having external teeth on an outer periphery thereof and oscillatingly rotating upon receiving an eccentric rotational force from the eccentric rotation portion; a cylindrical case (e.g., cylindrical case 15) having internal teeth (e.g., internal tooth pins 21) with a different number of teeth than the external teeth, which rotates while meshing with the external teeth while being rotatably supported on the base block; a metal powder detection sensor (e.g., metal powder detection sensor 48) that detects metal powder in the lubricating liquid filled in the space surrounded by the cylindrical case and the base block; The metal powder detection sensor is a reducer that is disposed near a journal portion (for example, journal 13a) of the crankshaft. (3) The base block has a support hole (e.g., support hole 47) that supports the journal portion via a bearing (e.g., bearing 22), 3. The reducer according to claim 2, wherein the metal powder detection sensor is fixed in the support hole. (4) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the input rotation, The reducer is A base block and an input rotor that receives power from a drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism; a metal powder detection sensor that detects metal powder in the lubricating liquid filled in the space surrounded by the cylindrical case and the base block, The metal powder detection sensor is a drive unit disposed near a bearing portion of the input rotor disposed at a position axially separated from the reduction mechanism portion.

[0122] (5) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the speed of the input rotation; a steering mechanism that operates by receiving the power reduced by the reducer, The reducer is A base block and an input rotor that receives power from a drive device and rotates while being rotatably supported by the base block; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism; a metal powder detection sensor that detects metal powder in the lubricating liquid filled in the space surrounded by the cylindrical case and the base block, The metal powder detection sensor is disposed in the vicinity of a bearing portion of the input rotor, which is disposed at a position axially spaced from the reduction mechanism portion.

[0123] Eighth Embodiment FIG. 19 is a diagram showing a vertical cross section of a drive unit 10 employing a reducer 711 according to the eighth embodiment. The reducer 711 of this embodiment includes a base block 12 fixed to the vehicle, multiple crankshafts 13 (input rotors) rotatably supported on the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radial outside of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner peripheral surface of the cylindrical case 15, and an internally toothed pin 21 is held in the pin groove 20. The internally toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0124] The base block 12 includes a first base block 12A disposed at one end in the axial direction, and a second base block 12B disposed at the other end in the axial direction. The first base block 12A has a disk-shaped base plate portion 12Aa and a fixing flange 12Ab that is bent axially outward from the outer peripheral edge of the base plate portion 12Aa in a crank shape and then protrudes radially outward. The second base block 12B has a disk-shaped base plate 12Ba having approximately the same outer diameter as the base plate 12Aa of the first base block 12A, and a plurality of connecting posts 12Bb extending from an end face of the base plate 12Ba toward the base plate 12Aa of the first base block 12A. A plurality of connecting posts 12Bb (for example, three) are arranged on the end face of the base plate 12Ba on a concentric circle centered on the central axis o1.

[0125] The second base block 12B has end faces of the connecting posts 12Bb butted against end faces of the base plate portion 12Aa of the first base block 12A, and each connecting post 12Bb is fixed to the first base block 12A by fitting with a tapered pin 57. The tapered pin 57 is fitted into the base plate portion 12Aa and the connecting posts 12Bb from the side of the base plate portion 12Aa of the first base block 12A.

[0126] The first oscillating gear 14A and the second oscillating gear 14B are formed with a plurality of relief holes 18 through which the connecting struts 12Bb of the first base block 12A pass. The relief holes 18 are formed to be sufficiently larger than the outer surface shape of the connecting struts 12Bb so that the connecting struts 12Bb do not interfere with the oscillating rotation of the first oscillating gear 14A and the second oscillating gear 14B.

[0127] A connecting shaft 55 is formed at the radial center of the base plate 12Ba of the second base block 12B, extending toward the base plate 12Aa of the first base block 12A. The connecting shaft 55 has a larger diameter than the tapered pin 57 fitted into the connecting support 12Bb. In contrast, an insertion hole 58 into which the tip of the connecting shaft 55 is inserted and a substantially circular recess 59, which penetrates the insertion hole 58 and into which the tip of the connecting shaft 55 is disposed, are formed at the radial center of the base plate 12Aa of the first base block 12A. A nut 56 is disposed in the recess 59 and fastened to the tip of the connecting shaft 55 that penetrates the insertion hole 58. The nut 56 is fastened to the tip of the connecting shaft 55 to axially secure the first base block 12A and the second base block 12A. The nut 56 preferably has a locking function. In this embodiment, the nut 56 serves as a locking member.

[0128] On the other hand, the cylindrical case 15 has a case main body 15a that covers the radial outside of the reduction mechanism, and an output arm 27 that extends radially outward from the outer peripheral surface of one axial end of the case main body 15a (the side opposite to the side where the motor 8 is disposed). The case main body 15a is rotatably supported via bearings 19 on the outer peripheral surfaces of a base plate portion 12Aa of the first base block 12A and a base plate portion 12Ba of the second base block 12B. The output arm 27 is formed integrally with the case main body 15a by casting or the like. The output arm 27 is formed, for example, in the shape of a rectangular pillar.

[0129] As described above, in the reducer 811 of this embodiment, the output arm 27 extending radially outward from the outer peripheral surface of the cylindrical case 15 is formed integrally with the cylindrical case 15. Therefore, unlike when a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to the flange, it is possible to output a stable torque to the outside through the output arm 27 without increasing the size and weight of the entire reducer 811 or the number of manufacturing steps.

[0130] In the reducer 711 of this embodiment, the first base block 12A and the second base block 12B are fixed in the axial direction by a connecting shaft 55 that protrudes from the radial center position of the second base block 12B and penetrates the base plate portion 12Aa of the first base block 12A, and a nut 56 that penetrates the base plate portion 12Aa and is fastened to the tip of the connecting shaft 55. A plurality of connecting struts 12Bb that protrude from the second base block 12B are connected to the base plate portion 12Aa of the first base block 12A by tapered pins 57, thereby fixing the first base block 12A and the second base block 12B in the rotational direction.

[0131] Therefore, in the reducer 711 of this embodiment, the axial fixation (displacement restriction) and rotational fixation (displacement restriction) of the first base block 12A and the second base block 12B can be shared between the central connecting shaft 55 and nut 56 and the multiple tapered pins 57 connected to each connecting strut 12Bb. Therefore, when the reducer 711 of this embodiment is used, the external shape of the connecting strut 12Bb can be made smaller than when each connecting strut 12Bb and the second base block are connected with multiple bolts, and the number of parts required for fixation can be reduced. Furthermore, since the external shape of the connecting strut 12Bb can be made smaller, the relief holes 18 formed in the first oscillating gear 14A and the second oscillating gear 14B can be made smaller, thereby increasing the durability of these oscillating gears 14A, 14B.

[0132] Other inventions that can be extracted from the above eighth embodiment are listed below. (1) A first base block (e.g., the first base block 12A) and a second base block (e.g., the first base block 12A) that are connected to each other at multiple points around a central axis (e.g., via connecting columns 12Bb), an oscillating gear having an escape hole through which the connecting strut passes and supported by the first base block and the second base block so as to be oscillatingly rotatable; a cylindrical case to which reduced rotation is transmitted from the oscillating gear, The first base block and the second base block are fixed in the axial direction by a connecting shaft that protrudes from a radial center position of one of the base blocks and penetrates the other, and a slip-out prevention member that is fixed to the connecting shaft that penetrates the other, the connecting support is integrally formed with either the first base block or the second base block, The tip of the connecting strut is fixed to the other of the first base block and the second base block by fitting a pin (for example, a tapered pin 57).

[0133] (2) A first base block (e.g., the first base block 12A) and a second base block (e.g., the first base block 12A) that are connected to each other at multiple points around the central axis via connecting columns (e.g., connecting columns 12Bb), a crankshaft (e.g., crankshaft 13) having an eccentric rotation portion (e.g., eccentric rotation portion 13b), rotatably supported by the first base block and the second base block, and receiving power from a drive device (e.g., motor 8); an oscillating gear (e.g., first oscillating gear 14A, second oscillating gear 14B) having an escape hole (e.g., escape hole 18) through which the connecting strut passes and having external teeth (e.g., external teeth 14Aa, 14Bb) on its outer periphery, and oscillatingly rotating upon receiving eccentric rotational force from the eccentric rotation portion; a cylindrical case (e.g., cylindrical case 15) having internal teeth (e.g., internal tooth pins 21) with a number of teeth different from that of the external teeth, and which is rotatably supported on the base block and rotates while meshing with the external teeth; The first base block and the second base block are fixed in the axial direction by a connecting shaft (e.g., connecting shaft 55) that protrudes from a radial center position of one of the base blocks and penetrates the other, and a slip-out prevention member (e.g., nut 56) that is fixed to the connecting shaft that penetrates the other, the connecting support is integrally formed with either the first base block or the second base block, The tip of the connecting strut is fixed to the other of the first base block and the second base block by fitting a pin (for example, a tapered pin 57).

[0134] (3) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the input rotation, The reducer is a first base block and a second base block connected to each other at multiple points around a central axis via connecting columns; an oscillating gear having an escape hole through which the connecting strut passes and supported by the first base block and the second base block so as to be oscillatingly rotatable; a cylindrical case to which reduced rotation is transmitted from the oscillating gear, The first base block and the second base block are fixed in the axial direction by a connecting shaft that protrudes from a radial center position of one of the base blocks and penetrates the other, and a slip-out prevention member that is fixed to the connecting shaft that penetrates the other, the connecting support is integrally formed with either the first base block or the second base block, A drive unit in which the tip of the connecting support is fixed to the other of the first base block and the second base block by fitting with a pin.

[0135] (4) a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the speed of the input rotation; a steering mechanism that operates by receiving the power reduced by the reducer, The reducer is a first base block and a second base block connected to each other at multiple points around a central axis via connecting columns; an oscillating gear having an escape hole through which the connecting strut passes and supported by the first base block and the second base block so as to be oscillatingly rotatable; a cylindrical case to which reduced rotation is transmitted from the oscillating gear, The first base block and the second base block are fixed in the axial direction by a connecting shaft that protrudes from a radial center position of one of the base blocks and penetrates the other, and a slip-out prevention member that is fixed to the connecting shaft that penetrates the other, The connecting support is integrally formed with either the first base block or the second base block. A steering assist device in which the tip of the connecting strut is fixed to the other of the first base block and the second base block by fitting with a pin.

[0136] The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0137] 1...steering assist device, 6...steering mechanism, 8...motor (drive device), 10...drive unit, 11...reduction gear, 12...base block, 13...crankshaft (input rotating body), 14A...first oscillating gear (oscillating gear, reduction mechanism part), 14B...second oscillating gear (oscillating gear, reduction mechanism part), 15...cylindrical case, 21...internal tooth pin (internal tooth, reduction mechanism part), 27...output arm

Claims

1. an input rotor that rotates by receiving power from a drive device; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, The cylindrical case has an output arm integrally formed therewith, the output arm extending radially outward from the outer peripheral surface of the cylindrical case and transmitting an operating force to the outside.

2. a base block that rotatably supports the input rotor and the cylindrical case, the base block has a fixing flange that projects radially outward from a position adjacent to one end of the cylindrical case in the axial direction and is fixed to another member; The reducer according to claim 1 , wherein the output arm extends radially outward from the other axial end of the cylindrical case.

3. A base block and a crankshaft having an eccentric rotation portion, rotatably supported by the base block, and receiving power from a drive device; an oscillating gear having external teeth on its outer periphery and adapted to oscillate and rotate by receiving an eccentric rotational force from the eccentric rotation portion; a cylindrical case having a number of internal teeth different from that of the external teeth, the cylindrical case being rotatably supported by the base block and rotating while meshing with the external teeth, The cylindrical case has an output arm integrally formed therewith, the output arm extending radially outward from the outer peripheral surface of the cylindrical case and transmitting an operating force to the outside.

4. a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the input rotation, The reducer is an input rotor that receives power from the drive device and rotates; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, The drive unit has an output arm integrally formed with the cylindrical case, the output arm extending radially outward from the outer circumferential surface of the cylindrical case and transmitting an operating force to the outside.

5. a drive unit that outputs rotational power; a reducer that receives power from the drive device and reduces the speed of the input rotation; a steering mechanism that operates by receiving the power reduced by the reducer, The reducer is an input rotor that receives power from the drive device and rotates; a speed reduction mechanism that reduces the rotation speed of the input rotor; a cylindrical case that covers the outside of the reduction mechanism and that rotates by receiving power that has been reduced by the reduction mechanism, The steering assist device has an output arm integrally formed with the cylindrical case, the output arm extending radially outward from the outer peripheral surface of the cylindrical case and transmitting an operating force to the steering mechanism.

Images