Reducer, drive unit, and steering assist device

Abstract

To provide a speed reducer, a drive unit and a steering assist device capable of outputting stable torque to the outside through an output arm, without increasing the size or weight of the whole device or increasing a manufacturing man-hour.SOLUTION: A speed reducer is equipped with an input rotator, a speed reduction mechanism portion, and a cylindrical case 15. The speed reducer rotates by receiving power from a drive device. The speed reduction mechanism portion reduces the rotations of the input rotator. The cylindrical case 15 covers the outside of the speed reduction mechanism portion and rotates by receiving power whose speed is reduced by the speed reduction mechanism portion. The cylindrical case 15 is integrally formed with an output arm 27 that extends from an outer peripheral surface of the cylindrical case 15 outward in a diametrical direction and transmits operational force to the outside.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] As a device for a vehicle steering system, a steering assist device that assists a driver's steering operation by the force of hydraulic pressure or an electric motor is known. The steering assist device includes a steering mechanism that steers wheels according to an operation of a steering part (steering wheel), and a drive unit that outputs an assist force corresponding to a steering force applied to the steering part to the steering mechanism. (For example, refer to Patent Document 1)

[0003] The drive unit used in the above steering assist device includes a drive device such as an electric motor, and a speed reducer that reduces the output of the drive device. The speed reducer includes an input rotating body that rotates by receiving power from the drive device, a speed reduction mechanism part that reduces the rotation of the input rotating body, and an output rotating body that rotates by receiving the power reduced by the speed reduction mechanism part, and is configured to transmit the rotation of the output rotating body to the steering mechanism.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As a speed reducer used in a steering assist device, a speed reducer in which a cylindrical case is arranged on the radially outer side of a speed reduction mechanism part and the cylindrical case is used as an output rotating body is known. In the case of this speed reducer, an output arm for transmitting an operating force to the steering mechanism is attached to the cylindrical case by bolt fastening.

[0006] However, in this case, since the output arm is fixed to the cylindrical case by bolt fastening, 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] As a countermeasure, a method is employed in which a fixing flange is provided on the outer circumference of the cylindrical case, and the output arm is fastened and fixed to the flange with multiple bolts. However, in this method, due to the bolt fastening, a thick flange must be provided on the outer circumference of the cylindrical case, and bolt insertion holes and screw holes must be formed in the flange. This tends to make the entire gearbox larger and heavier, and also results in increased manufacturing man-hours.

[0008] The present invention provides a reduction gear, a drive unit, and a steering assist device that can output stable torque to the outside through an output arm without increasing the overall size and weight of the device or increasing manufacturing man-hours. [Means for solving the problem]

[0009] A gearbox according to one aspect of the present invention comprises an input rotating body that rotates by receiving power from a drive device, a reduction mechanism that reduces 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 reduced by the reduction mechanism. The reduction mechanism comprises a base block that rotatably supports the input rotating body and the cylindrical case, and the axial edges on both sides of the cylindrical case are rotatably supported by the base block via bearings. The cylindrical case has an output arm integrally formed therein that extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. The output arm is formed to overlap radially with at least one of the bearings.

[0010] The aforementioned The base block has 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 reduction gear 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, which receives power input from a drive device, an oscillating gear having external teeth on its outer circumference and receiving an eccentric rotational force from the eccentric rotating portion, which oscillates and rotates, and a cylindrical case having internal teeth with a different number of teeth from the external teeth, which rotates in mesh with the external teeth while being rotatably supported on the base block. The axial edges on both sides of the cylindrical case are rotatably supported by the base block via bearings. The cylindrical case has an output arm integrally formed therein that extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. The output arm is formed to overlap radially with at least one of the bearings.

[0012] A drive unit according to one aspect of the present invention comprises a drive device that outputs rotational power, and a reduction gear that receives power from the drive device and reduces the input rotation, wherein the reduction gear comprises an input rotating body that rotates by receiving power from the drive device, a reduction mechanism that reduces 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 reduced by the reduction mechanism. The reduction mechanism comprises a base block that rotatably supports the input rotating body and the cylindrical case, and the axial edges on both sides of the cylindrical case are rotatably supported by the base block via bearings. The cylindrical case has an output arm integrally formed therein that extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. The output arm is formed to overlap radially with at least one of the bearings.

[0013] A steering assist device according to one aspect of the present invention comprises a drive device that outputs rotational power, a reduction gear that receives power from the drive device and reduces the input rotation, and a steering mechanism that operates by receiving the power reduced by the reduction gear, wherein the reduction gear comprises an input rotating body that rotates by receiving power from the drive device, a reduction mechanism that reduces 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 reduced by the reduction mechanism, The reduction mechanism comprises a base block that rotatably supports the input rotating body and the cylindrical case, and the axial edges on both sides of the cylindrical case are rotatably supported by the base block via bearings. The cylindrical case has an output arm integrally formed therein that extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. The output arm is formed to overlap radially with at least one of the bearings. [Effects of the Invention]

[0014] Since the output arm extending radially outward from the outer peripheral surface of the cylindrical case is integrally formed with the cylindrical case, the above-described speed reducer can output stable torque to the outside through the output arm without causing an increase in the size and weight of the entire device or an increase in the manufacturing man-hours.

Brief Description of Drawings

[0015] [Figure 1] Schematic general configuration diagram of the steering assist device of the embodiment. [Figure 2] Longitudinal sectional view of the speed reducer of the first embodiment. [Figure 3] Cross-sectional view showing a modified example of the speed reducer of the first embodiment. [Figure 4] Cross-sectional view showing another modified example of the speed reducer of the first embodiment. [Figure 5] Longitudinal sectional view of the speed reducer of the second embodiment. [Figure 6] View seen from the arrow VI in FIG. 5 of the speed reducer of the second embodiment. [Figure 7] Side view of the speed reducer of the second embodiment. [Figure 8] Longitudinal sectional view of the speed reducer of the third embodiment. [Figure 9] Cross-sectional view showing a first modified example of the speed reducer of the third embodiment. [Figure 10] Cross-sectional view showing a second modified example of the speed reducer of the third embodiment. [Figure 11] Cross-sectional view showing a third modified example of the speed reducer of the third embodiment. [Figure 12] Longitudinal sectional view of the drive unit of the fourth embodiment. [Figure 13] View seen from the arrow XIII in FIG. 12 of the speed reducer of the fourth embodiment. [Figure 14] View corresponding to the view seen from the arrow XIII in FIG. 12 showing a modified example of the speed reducer of the fourth embodiment. [Figure 15] Longitudinal sectional view of the drive unit of the fifth embodiment. [Figure 16] Longitudinal sectional view of the drive unit of the sixth embodiment. [Figure 17] View seen from the arrow XVII in FIG. 16 of the speed reducer of the sixth embodiment. [Figure 18]A longitudinal cross-sectional view of the drive unit according to the seventh embodiment. [Figure 19] A longitudinal cross-sectional view of the drive unit according to the eighth embodiment. [Modes for carrying out the invention]

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

[0017] <Steering assist device> Figure 1 is a schematic diagram of the steering assist device 1 of a vehicle employing the drive unit 10 of this embodiment. The steering assist device 1 comprises a steering wheel 2, a steering shaft 3, a drive unit 10 which also serves as a steering transmission unit, and a steering mechanism 6 which is steered through the drive unit 10. The steering wheel 2 is positioned 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 together with the steering wheel 2.

[0018] The drive unit 10 includes a motor 8, which is a drive device for steering assist, and a reduction gear 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 reduction gear 11 via a gear mechanism (not shown). The input section of the reduction gear 11 combines the input steering torque and the assist torque from the motor 8 and transmits the combined torque to the reduction gear section. Therefore, the combined steering torque and assist torque are output to the output section (steering mechanism 6 side) of the reduction gear 11 after being reduced to a predetermined reduction ratio.

[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, described later, is provided on the output side of the reduction gear 11. The tip of the output arm 27 is connected to the vehicle's steering mechanism 6. The steering mechanism 6 is an operating arm that receives operating force from the output arm 27. 6b and the operating arm 6b The tie rod steers the front wheels of the vehicle by its operation. 6a It is equipped with the following features. The reduction gears 11, 111, 211, 311, 411, 511, 611, and 711 of each embodiment described below can be used in the steering assist device 1 shown in Figure 1.

[0021] <First Embodiment> Figure 2 is a diagram showing a longitudinal cross-section of the gearbox 11 of the first embodiment. The reduction gear 11 comprises a base block 12 fixedly installed on the vehicle, a plurality (for example, three) of 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 two eccentric rotating parts 13b of each crankshaft 13, and a cylindrical case 15 rotatably supported on the outer circumferential surface of the base block 12 so as to cover the radially outer sides 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-axis cylinder. In the following, for the sake 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 centered on the central axis o1 will be referred to as the radial direction. Furthermore, with respect to the axial direction, the side facing inward towards the object will be referred to as the axial inward direction, and the opposite side will be referred to as the axial outward direction. These designations will also be used in the description of other embodiments.

[0023] The base block 12 comprises a first base block 12A positioned at one end in the axial direction and a second base block 12B positioned at the other end in the axial direction. The first base block 12A has a disc-shaped substrate portion 12Aa and a fixed flange 12Ab that is bent in a crank shape axially outward from the outer peripheral edge of the substrate portion 12Aa and then protrudes radially outward. The case of the motor 8 is fastened and fixed to the fixed flange 12Ab. The second base block 12B has a disc-shaped substrate portion 12Ba having approximately the same outer diameter as the substrate portion 12Aa of the first base block 12A, and a plurality of connecting support columns 12Bb extending from the end face of the substrate portion 12Ba toward the direction of the first base block 12A. Multiple connecting support columns 12Bb are arranged (for example, three) on concentric circles centered on the central axis o1 of the end face of the substrate portion 12Ba.

[0024] The second base block 12B has its connecting column 12Bb end face abutted against 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 by bolts 16. Reference numeral 17 in Figure 2 indicates a positioning pin used to position the first base block 12A on each connecting column 12Bb before fastening with bolts 16.

[0025] An axial gap is provided between the substrate portions 12Aa and 12Ba of the first base block 12A and the second base block 12B. The first oscillating gear 14A and the second oscillating gear 14B are positioned in this gap. Multiple relief holes 18 are formed in the first oscillating gear 14A and the second oscillating gear 14B, through which each connecting column 12Bb of the first base block 12A passes. The relief holes 18 are formed to be sufficiently larger than the outer surface shape of the connecting columns 12Bb so that each connecting column 12Bb does not obstruct the oscillating rotation of the first oscillating gear 14A and the second oscillating gear 14B.

[0026] The cylindrical case 15 is positioned across the outer circumferential surface of the substrate portion 12Aa of the first base block 12A and the outer circumferential surface of the substrate portion 12Ba of the second base block 12B. The axial edges on both sides of the cylindrical case 15 are rotatably supported on the outer circumferential surfaces of the substrate portions 12Aa and 12Ba of the first and second base blocks 12A and 12B via bearings 19. In addition, a plurality of pin grooves 20 are formed on the inner circumferential surface of the axial central region of the cylindrical case 15 (the region facing the outer circumferential surfaces of the first and second oscillating gears 14A and 14B), extending parallel to the central axis o1 of the first and second base blocks 12A and 12B. A substantially cylindrical internal tooth pin 21 is rotatably housed in each pin groove 20. The plurality of internal tooth pins 21 attached to the inner circumferential surface of the cylindrical case 15 face the outer circumferential surfaces of the first and second oscillating gears 14A and 14B, respectively.

[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 and 14Ba are formed on the outer circumferential surfaces of the first oscillating gear 14A and the second oscillating gear 14B, respectively, which mesh with and contact a plurality of internal tooth pins 21 arranged on the inner circumferential surface of the cylindrical case 15. The number of teeth on the external teeth 14Aa and 14Ba formed on the outer circumferential surfaces 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 (pin grooves 20) (for example, one less).

[0028] 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 has a pair of journal portions 13a formed axially spaced apart, and each of these journal portions 13a is supported by bearings 22. The two eccentric rotating portions 13b described above are positioned between the pair of journal portions 13a of each crankshaft 13.

[0029] A gear mounting portion 13c is formed at one end of the crankshaft 13 in the axial direction (the side where the motor 8 is located), adjacent to the journal portion 13a. 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 the output gear 23 on the motor 8 side is attached to the gear mounting portion 13c.

[0030] The crank gear 24 meshes with a gear of a gear mechanism (not shown) on the steering shaft 3 (see Figure 1). 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] Furthermore, the first oscillating gear 14A and the second oscillating gear 14B have support holes 25 through which the corresponding eccentric rotating portions 13b of the crankshaft 13 are inserted. The support holes 25 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 bearings 26 (cylindrical roller bearings).

[0032] When the reduction gear 11 receives torque from the steering shaft 3 and the motor 8, and the multiple crankshafts 13 rotate in one direction, each eccentric rotating portion 13b of the crankshafts 13 pivots in the same direction at a predetermined radius, and consequently 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 and 14Ba of the first oscillating gear 14A and the second oscillating gear 14B contact and mesh with a plurality of internal tooth pins 21 held on the inner circumference of the cylindrical case 15.

[0033] In the reduction gear 11, the number of teeth on the external teeth 14Aa and 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 body 15a side. Therefore, while the first oscillating gear 14A and the second oscillating gear 14B rotate once, the external teeth 14Aa and 14Ba of the first oscillating gear 14A and the second oscillating gear 14B push 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 the rotation of the cylindrical case 15. In this embodiment, the crankshaft 13 constitutes the input rotating body of the reduction gear 11. Furthermore, the first oscillating gear 14A and the second oscillating gear 14B, together with the internal tooth pin 21 and the like, constitute the reduction mechanism in the reduction gear 11.

[0034] Here, the cylindrical case 15 has a case body portion 15a that covers the radially outer side 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 body portion 15a. In this embodiment, the output arm 27 extends radially outward from approximately the axial center position of the case body portion 15a. The output arm 27 is integrally formed with the case body portion 15a by casting or the like.

[0035] Reference numeral 28 in Figure 2 indicates a sealing member that seals the space between the first base block 12A (substrate portion 12Aa) and the case body portion 15a (substrate portion), and the space between the second base block 12B (substrate portion 12Ba) and the case body portion 15a. The space enclosed by the cylindrical case 15 and the base block 12, in which the reduction gear mechanism is arranged, is filled with lubricating fluid for lubricating the mechanical moving parts such as the reduction gear mechanism.

[0036] As described above, in the gearbox 11 of this embodiment, the output arm 27 extending radially outward from the outer circumferential surface of the cylindrical case 15 is integrally formed with the cylindrical case 15. Therefore, unlike the case in which a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to that flange, a stable torque can be output to the outside through the output arm 27 without increasing the overall size and weight of the gearbox 11 or increasing the manufacturing man-hours.

[0037] Furthermore, the drive unit 10 employing the reduction gear 11 of this embodiment can reduce the weight of the output side of the reduction gear 11, thereby suppressing power consumption in the motor 8.

[0038] Furthermore, the steering assist device 1 employing the drive unit 10 of this embodiment allows for miniaturization and weight reduction of the output side of the reduction gear 11, thereby increasing the flexibility of vehicle placement and contributing to vehicle weight reduction.

[0039] In the reduction gear 11 shown in Figure 2, the output arm 27 extends radially from approximately the axial center of the cylindrical case 15. However, the output arm 27 may also extend radially outward from one end of the cylindrical case 15 in the axial direction, as shown in the modified example in Figure 3. In the modified example shown in Figure 3, the output arm 27 extends radially outward from the end adjacent to the fixed flange 12Ab that protrudes radially outward from the substrate portion 12Aa of the first base block 12A.

[0040] Furthermore, 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 located), as shown in the modified example in Figure 4. In this configuration, the output arm 27 extends radially outward from the end of the fixed flange 12Ab opposite to the protruding side, so the output arm 27 is less likely to interfere with assembly work when assembling components such as the motor 8. Therefore, adopting this configuration can improve assembly workability.

[0041] <Second Embodiment> In each embodiment described below, the same reference numerals are used for parts common to the first embodiment. Figure 5 is a cross-sectional view of the gearbox 111 of the second embodiment. Figure 6 is a view of the gearbox 111 as seen through arrow VI in Figure 5, and Figure 7 is a side view of the gearbox 111. The reduction gear 111 of this embodiment comprises a base block 12 fixed to the vehicle, a plurality of 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 in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radially outer sides of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner circumferential surface of the cylindrical case 15, and an internal tooth pin 21 is held in the pin groove 20. The internal tooth pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes the reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0042] The cylindrical case 15 includes a case body portion 15a that covers the radially outer side of the reduction mechanism, and an output arm 27 that extends radially outward from the outer circumferential surface of one axial end of the case body portion 15a (the side opposite to the side where the motor 8 is located). The output arm 27 is integrally formed with the case body portion 15a by casting or the like. The output arm 27 is formed, for example, in a prismatic shape.

[0043] Strain gauges 90 are attached to the four sides of the output arm 27 to detect the stress acting on the output arm 27. The strain gauges 90 are electrically connected to the input 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) is mounted in an appropriate location on the reduction gear 111, for example, between the base block 12 and the cylindrical case 15, to detect the rotational speed of the output arm 27. The rotation detection device is electrically connected to the input of a controller (not shown) and outputs a detection signal indicating the rotational 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 rotational speed acting on the output arm 27, and determines from the results whether the reducer 111 is approaching its service limit. If the controller determines that the reducer 111 is approaching its service limit, it notifies the user that it is time to replace the reducer 111 by illuminating a warning indicator, etc.

[0046] As described above, in the gearbox 111 of this embodiment, the output arm 27 extending radially outward from the outer circumferential surface of the cylindrical case 15 is integrally formed with the cylindrical case 15. Therefore, unlike the case in which a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to that flange, a stable torque can be output to the outside through the output arm 27 without increasing the overall size and weight of the gearbox 111 or increasing the manufacturing man-hours.

[0047] Furthermore, in this embodiment, the gearbox 111 has a strain gauge 90 attached to an output arm 27 that extends radially outward from the outer circumferential surface of the cylindrical case 15, for detecting the stress acting on the output arm 27. Therefore, by using the detected value from the strain gauge 90, it is possible to accurately determine whether or not the gearbox 111 is approaching its service limit. In particular, if the reduction gear 111 is equipped with a rotation detection device along with the strain gauge 90 described above, it becomes possible to more accurately determine whether or not the reduction gear 111 is approaching its service limit.

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

[0049] (2) A base block (for example, base block 12) and A crankshaft (for example, crankshaft 13) having an eccentric rotating portion and being rotatably supported on the base block, to which power is input from the drive device, A rocking gear (for example, first and second rocking gears 14A and 14B) having external teeth on its outer circumference and receiving an eccentric rotational force from the eccentric rotating part, The system includes a cylindrical case (e.g., cylindrical case 15) having internal teeth with a different number of teeth from the external teeth, which is rotatably supported on the base block and rotates in mesh with the external teeth, The cylindrical case has an output arm (for example, an output arm 27) integrally formed thereon, which extends radially outward from the outer circumferential surface of the cylindrical case and transmits operating force to the outside. A gearbox is equipped with a strain gauge (for example, strain gauge 90) attached to the output arm for detecting the stress acting on the output arm.

[0050] (3) A drive device that outputs rotational power, The system includes a reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The aforementioned reduction gear is An input rotating body that rotates by receiving power from the aforementioned drive device, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The cylindrical case has an output arm integrally formed thereon, which extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. The output arm is fitted with a strain gauge for detecting the stress acting on the output arm, and this is part of the drive unit.

[0051] (4) A drive device that outputs rotational power, A reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The steering mechanism operates by receiving power reduced by the aforementioned reduction gear, The aforementioned reduction gear is An input rotating body that rotates by receiving power from the aforementioned drive device, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The cylindrical case has an output arm integrally formed thereon, which extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. A steering assist device is provided, in which a strain gauge for detecting stress acting on the output arm is attached to the output arm.

[0052] <Third Embodiment> Figure 8 shows a longitudinal cross-section of the gearbox 211 of the third embodiment. The reduction gear 211 comprises a base block 12 fixed to the vehicle, a plurality of crankshafts 13 (input rotating bodies) rotatably supported by the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate in response to the rotation of the crankshafts 13, and a cylindrical case 115 covering the radially outer surfaces of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner circumferential surface of the cylindrical case 115, and an internal tooth pin 21 is held in the pin groove 20. The internal tooth pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes the reduction mechanism. The specific configuration of the crankshaft 13 and the reduction mechanism is the same as in the first embodiment.

[0053] The base block 12 includes a first base block 12A positioned at one end in the axial direction and a second base block 12B positioned at the other end in the axial direction. The second base block 12B has a connecting support column 12Bb that abuts against the base plate portion 12Aa of the first base block 12A, and in this state, the connecting support column 12Bb is fixed to the base plate portion 12Aa by bolts 16.

[0054] A bearing support surface 30 with a predetermined outer diameter is formed on the outer circumferential surface of the substrate 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 combination angular contact bearing is used as this bearing 31. Hereinafter, the bearing 31 will be referred to as the "combination angular contact bearing 31". The combination angular contact bearing 31 in this embodiment has a configuration in which two angular contact ball bearings with a contact angle are arranged in the axial direction. The combination angular contact bearing 31 can support radial loads and thrust loads between the base block 12 and the cylindrical case 115. Furthermore, on the outer circumferential surface of the substrate portion 12Aa, a seal support surface 32 is formed at a position axially outward from the bearing support surface 30, and has a larger outer diameter than the bearing support surface 30. An annular seal member 28 is interposed between this seal support surface 32 and the inner circumferential surface of the cylindrical case 115 to seal the space 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 circumference of the cylindrical case 15. In this embodiment, the base plate portion 12Aa constitutes the insertion portion of the base block 12. The insertion portion of the base block 12 is inserted into the inside of the cylindrical case 115 together with the input rotating body (crankshaft 13) and the reduction mechanism portion (first and second oscillating gears 14A, 14B, etc.) from one end of the cylindrical case 115 in the axial direction. The combined angular contact bearing 31 and the seal member 28 are interposed between the insertion portion and the cylindrical case 115. The seal member 28 seals the space between the cylindrical case 115 and the insertion portion at one end of the cylindrical case 115 in the axial direction, relative to the combined angular contact bearing 31.

[0056] The outer circumferential surface of the bearing support surface 30 of the substrate portion 12Aa, on the end opposite to the seal support surface 32, and the inner circumferential surface of the axially inner inner ring 31ib of the combined angular contact bearing 31 are provided with screw fastening portions 33 that can be fixed by screw threads and screw grooves. The two inner rings 31ia and 31ib of the combined angular contact bearing 31 are temporarily locked to the base block 12 side (first base block 12A side) by bringing the axially outer inner ring 31ia into contact with the stepped surface between the bearing support surface 30 and the seal support surface 32, and fixing 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 includes a case body portion 115a that covers the radially outer side of the reduction mechanism, an output arm 27 extending radially outward from the outer circumferential surface of one axial end (the side where the motor 8 is located) of the case body portion 115a, an end wall 36 that closes the other axial end of the case body portion 115a, and an auxiliary cylindrical portion 34 fixed to one axial end surface of the case body portion 115a by welding. The output arm 27 and the end wall 36 are integrally formed with the case body portion 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 body portion 115a. A screw-fastening portion 35 is provided on the inner circumferential surface of the auxiliary cylinder portion 34, specifically the region 34a closer to the case body portion 115a, and on the outer circumferential surface of the axially outer ring 31oa of the combined angular contact bearing 31, allowing for fixing by screw threads and grooves. The two outer rings 31oa and 31ob of the combined angular contact bearing 31 are temporarily locked to the cylindrical case 15 by bringing the axially inner outer ring 31ob into contact with the stepped surface of the pin groove 20 of the case 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. In addition, the outer circumferential surface of the sealing member 28 contacts the region 34b of the inner circumferential surface of the auxiliary cylinder portion 34 that is spaced apart from the case body portion 115a. In this embodiment, the area 34a (screw-fastened portion 35) of the inner circumferential surface of the auxiliary cylinder portion 34 that is closer to the case body portion 115a constitutes the outer ring locking portion, and the area 34b of the inner circumferential surface of the auxiliary cylinder portion 34 that is separated from the case body portion 115a constitutes the seal contact portion. Furthermore, the space enclosed by the cylindrical case 115 and the base block 12, in which the reduction gear mechanism is located, is filled with lubricating fluid for lubricating the mechanical moving parts such as the reduction gear mechanism.

[0059] When assembling the reduction gear 211, first, the first and second oscillating gears 14A and 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 by bolts 16. In this state, the inner rings 31ia and 31ib of the combined angular contact bearing 31 are temporarily assembled to the outer circumferential surface of the base plate portion 12Aa of the first base block 12A as described above. Meanwhile, the outer rings 31oa and 31ob of the combined angular contact bearing 31 are temporarily assembled to the inner circumferential surface of the cylindrical case 115 as described above, and the sealing member 28 is attached to the inner circumferential surface of the auxiliary cylindrical portion 34.

[0060] Next, in this state, a portion of the base block 12 (the insertion portion of the second base block 12B and the first base block 12A) is inserted into the cylindrical case 115 from one end in the axial direction, together with the first and second oscillating gears 14A and 14B and the crankshaft 13. At this time, the combined angular contact bearing 31 is assembled, and the inner circumferential surface of the seal member 28 is brought into contact with the seal support surface 32 of the first base block 12A. After this, the base block 12 is prevented from coming out of the cylindrical case 15 by a dislodgement-restricting means (not shown). After this, lubricating fluid 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 sealing 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 gearbox 211 of this embodiment, the output arm 27 extending radially outward from the outer circumferential surface of the cylindrical case 115 is integrally formed with the cylindrical case 115. Therefore, unlike the case in which a fixing flange is provided on the cylindrical case 115 and a separate output arm is bolted to that flange, a stable torque can be output to the outside through the output arm 27 without increasing the overall size and weight of the gearbox 111 or increasing the manufacturing man-hours.

[0062] Furthermore, in the gearbox 211 of this embodiment, the other axial end of the cylindrical case 115 is completely closed by an end wall 36 that is integral with the cylindrical case 115. Therefore, leakage of lubricating fluid from the other axial end of the cylindrical case 115 can be prevented without placing a sealing member between the inner circumferential surface of the other axial end of the cylindrical case 115 and the base block 12.

[0063] Furthermore, in this embodiment, the reduction gear 211 has a combination angular contact bearing 31 positioned between the insertion portion of the base block 12 and the cylindrical case 115, and a sealing member 28 positioned on one end of the cylindrical case 115 in the axial direction relative to the combination angular contact bearing 31. Therefore, when assembling the reduction gear 211, a part of the base block 12 can be easily positioned inside the cylindrical case 115 from one end of the cylindrical case 115 together with the reduction mechanism and the crankshaft 13 (input rotating body), and the number of sealing member 28 parts used can be reduced.

[0064] Furthermore, in this embodiment, the gearbox 211 has an outer ring locking portion and a seal contact surface formed on the auxiliary cylindrical portion 34, which is a separate part from the case body portion 115a of the cylindrical case 115. Therefore, the auxiliary cylindrical portion 34, which is a small part, can be precisely machined and then attached to the case body portion 115a. Accordingly, when the gearbox 211 of this embodiment is adopted, the cylindrical case 115 can be manufactured with high precision and easily.

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

[0066] Figure 10 is a cross-sectional view showing a second modified example of the gearbox 211 of this embodiment. In the second modified example, the auxiliary cylinder portion 34A is fixed to the case body portion 115a by bolts 37 at the fixed flange portion 34Aa, similar to the first modified example. However, the outer ring locking portion of the auxiliary cylinder portion 34A is not a screw portion 35, but is composed of a locking projection 34Ab. The locking projection 34Ab protrudes radially inward from the inner circumferential surface of the auxiliary cylinder portion 34A and abuts against the axially outer end face of the outer ring 31oa of the angular contact bearing 31. This restricts the dislodgement of the outer ring 31oa of the angular contact bearing 31.

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

[0068] Other inventions that can be extracted from the third embodiment described above are listed below. (1) A base block (for example, base block 12) and An input rotating body (e.g., a crankshaft 13) is rotatably supported on the base block and rotates by receiving power from a drive device (e.g., a motor 8), A reduction mechanism (for example, a first oscillating gear 14A, a second oscillating gear 14B, and an internal tooth pin 21) that reduces the rotation of the input rotating body, The device comprises a cylindrical case (for example, a cylindrical case 115) that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The base block, together with the input rotating body and the reduction mechanism, has an insertion portion (for example, a substrate portion 12Aa) that is inserted into the inside of the cylindrical case from one end of the cylindrical case in the axial direction. Between the insertion portion and the cylindrical case, Combination angular contact bearings (for example, combination angular contact bearing 31) and A sealing member (for example, sealing member 28) is positioned at one end of the cylindrical case in the axial direction, rather than at the angular bearing in the combination, to seal the space between the cylindrical case and the insertion portion. The reduction gear has an end wall (for example, an end wall 36) integrally formed on the cylindrical case that closes the other end in the axial direction.

[0069] (2) The cylindrical case is A case body portion (for example, case body portion 115a) that houses the reduction gear portion inside, The case has an auxiliary cylindrical portion (for example, an auxiliary cylindrical portion 34) fixed to one end of the case body in the axial direction, The gearbox according to (1), wherein the inner circumferential surface of the auxiliary cylinder portion is provided with an outer ring locking portion (for example, a screw fastening portion 35) for locking the outer ring of the combination angular bearing and a seal contact portion (for example, a seal support surface 32) for contacting the seal member.

[0070] (3) Base block (for example, base block 12) and A crankshaft (e.g., crankshaft 13) having an eccentric rotating portion and rotatably supported on the base block, which receives power input from a drive device (e.g., motor 8), A rocking gear (for example, a first rocking gear 14A, a second rocking gear 14B) having external teeth on its outer circumference and receiving an eccentric rotational force from the eccentric rotating part, The device comprises a cylindrical case (e.g., cylindrical case 15) having internal teeth (e.g., internal tooth pin 21) with a different number of teeth from the external teeth, which is rotatably supported on the base block and rotates in mesh with the external teeth, The base block, together with the crankshaft and the oscillating gear, has an insertion portion (for example, a base plate portion 12Aa) that is inserted into the inside of the cylindrical case from one end of the cylindrical case in the axial direction. Between the insertion portion and the cylindrical case, Combination angular contact bearings (for example, combination angular contact bearing 31) and A sealing member (for example, sealing member 28) is positioned at one end of the cylindrical case in the axial direction, rather than at the angular bearing in the combination, to seal the space between the cylindrical case and the insertion portion. The reduction gear has an end wall (for example, an end wall 36) integrally formed on the cylindrical case that closes the other end in the axial direction.

[0071] (4) A drive device that outputs rotational power, The system includes a reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The aforementioned reduction gear is Base block and, An input rotating body that rotates by receiving power from the drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The base block, together with the input rotating body and the reduction mechanism, has an insertion portion that is inserted into the inside of the cylindrical case from one end of the cylindrical case in the axial direction. Between the insertion portion and the cylindrical case, Combination angular contact bearings, A sealing member is positioned at one end of the cylindrical case in the axial direction of the cylindrical case, rather than at the angular bearing in the combination, to seal the space between the cylindrical case and the insertion portion. The drive unit has an end wall integrally formed on the cylindrical case that closes the other end in the axial direction.

[0072] (5) A drive device that outputs rotational power, A reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The steering mechanism operates by receiving power reduced by the aforementioned reduction gear, The aforementioned reduction gear is Base block and, An input rotating body that rotates by receiving power from the drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The base block, together with the input rotating body and the reduction mechanism, has an insertion portion that is inserted into the inside of the cylindrical case from one end of the cylindrical case in the axial direction. Between the insertion portion and the cylindrical case, Combination angular contact bearings, A sealing member is positioned at one end of the cylindrical case in the axial direction of the cylindrical case, rather than at the angular bearing in the combination, to seal the space between the cylindrical case and the insertion portion. The steering assist device has an end wall integrally formed on the cylindrical case that closes the other end in the axial direction.

[0073] <Fourth Embodiment> Figure 12 is a cross-sectional view of the drive unit 10 employing the reduction gear 311 of the fourth embodiment. Figure 13 is a view of the reduction gear 311 as seen from arrow XIII in Figure 12. The reduction gear 311 of this embodiment comprises a base block 12 fixed to the vehicle, a plurality of 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 in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radially outer sides of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner circumferential surface of the cylindrical case 15, and an internal tooth pin 21 is held in the pin groove 20. The internal tooth pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes the reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0074] The base block 12 comprises a first base block 12A positioned at one end in the axial direction and a second base block 12B positioned at the other end in the axial direction. The second base block 12B has a connecting support column 12Bb that abuts against the base plate portion 12Aa of the first base block 12A, and in this state, the connecting support column 12Bb is fixed to the base plate portion 12Aa by bolts 16. Furthermore, a bolt insertion hole 40 that penetrates axially is formed in the fixing flange 12Ab that extends radially outward from the base plate portion 12Aa of the first base block 12A. Bolts for fixing the vehicle body are inserted into the bolt insertion hole 40.

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

[0076] Furthermore, a sealing member 28 is positioned between the outer circumferential surface of the substrate portion 12Aa of the first base block 12A and the inner circumferential surface of one axial end of the case body portion 15a, at an axially outward position of the bearing 19 on the one end, to seal the space between the substrate portion 12Aa and the case body portion 15a. Similarly, a sealing member 28 is positioned between the outer circumferential surface of the substrate portion 12Ba of the second base block 12B and the inner circumferential surface of the other axial end of the case body portion 15a, at an axially outward position of the bearing 19 on the other end, to seal the space 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 fluid for lubricating mechanical operating parts such as the reduction gear mechanism.

[0077] Here, 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 positioned to cover the axially outer region of the sealing member 28 between the substrate portion 12Ba and the cylindrical case 15. A rotation detection device 41 for detecting the relative rotational position and relative rotational speed between the base block 12 and the cylindrical case 15 is attached to the end flange 12Bc.

[0078] The rotation detection device 41 includes a detection target 42 attached to the other axial end face of the cylindrical case 15, and a target detection unit 43 attached to the end flange 12Bc on the second base block 12B side. The target detection unit 43 outputs a signal to a controller (not shown) corresponding to the change in the detection status of the detection target 42 due to the relative rotation between the base block 12 and the cylindrical case 15. For example, a magnetic detection device or an optical detection device can be used as the rotation detection device 41. The target detection unit 43 of the rotation detection device 41 has a detection surface 43a that protrudes radially outward so as to face the detection target 42 with a small gap in between. The detection surface 43a faces the detection target 42 in the axial direction. In this embodiment, the detection target 42 is attached to the other axial end face of the cylindrical case 15, and the target detection unit 43 is attached to the end flange 12Bc (substrate portion 12Ba). However, it is also possible to attach the target detection unit 43 to the axial end face of the cylindrical case 15 and 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, to detect and address situations where the output of the assist signal (drive signal) to the motor 8 has stopped for some reason, or to correct discrepancies between the motor 8's target output and its actual rotation. If the controller detects that the output of the assist signal (drive signal) to the motor 8 has stopped, the controller will, for example, release the reaction force of the motor 8 acting on the reduction gear 211. This prevents the driver's manual steering operation from being hindered by the reaction force of the motor 8.

[0080] As described above, in the gearbox 311 of this embodiment, the output arm 27 extending radially outward from the outer circumferential surface of the cylindrical case 15 is integrally formed with the cylindrical case 15. Therefore, unlike the case in which a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to that flange, a stable torque can be output to the outside through the output arm 27 without increasing the overall size and weight of the gearbox 211 or increasing the manufacturing man-hours.

[0081] Furthermore, since the gearbox 311 of this embodiment is equipped with a rotation detection device 41 that detects the relative rotation between the base block 12 and the cylindrical case 15, rotational information on the output side of the motor 8 can be acquired at the end of the gearbox 311 where there is ample space. As a result, the rotational information on the output side of the motor 8 can be effectively utilized by the controller without increasing the size of the motor 8.

[0082] Furthermore, in the gearbox 311 of this embodiment, the detection target 42 of the rotation detection device 41 is positioned on the axial end face of the cylindrical case 15, and the target detection unit 43 is positioned on the end face of the second base block 12B such 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 gearbox 311 from the outside, and maintenance of the rotation detection device 41 can also be easily performed.

[0083] Furthermore, in the gearbox 311 of this embodiment, an end flange 12Bc is provided on the outer circumference 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 unit 43 of the rotation detection device 41 is attached to the end flange 12Bc. As a result, the entry of foreign matter into the gap between the substrate portion 12Ba and the cylindrical case 15 (near the sealing member 28) can be prevented by the end flange 12Bc, and the detection surface 43a of the target detection unit 43 can be brought closer to the detection target 42 on the cylindrical case 15 side.

[0084] Figure 14 is a diagram similar to Figure 13, showing a modified example of the gearbox 311 of this embodiment. In the speed reducer 311 shown in Figures 12 and 13, the detection target 42 of the rotation detection device 41 is arranged in an annular shape on the axial end face of the cylindrical case 15. However, in the modified example shown in Figure 14, a semicircular detection target 42A is arranged on the axial end face of the cylindrical case 15. When the rotation range of the cylindrical case 15 (the rotation range of the output arm 27) used in the speed reducer 311 is narrow, the detection target 42A does not need to be a perfect annular shape. For this reason, the detection target 42A may be semicircular, as in the modified example shown in Figure 14, or even an arc shape other than a semicircle.

[0085] <Figure 5 Embodiment> Figure 15 is a diagram showing a vertical cross-section of the drive unit 10 employing the reduction gear 411 of the fifth embodiment. The basic configuration of the gearbox 411 in this embodiment is substantially the same as that of the gearbox 311 in the fourth embodiment, except for the mounting section for the rotation detection device 41. For this reason, in the following description, the same reference numerals are used for parts common to the gearbox 311 in the fourth embodiment, and some redundant explanations are omitted.

[0086] The gearbox 411 is formed such that the axial end of the substrate portion 12Ba of the second base block 12B protrudes axially outward from the other axial end of the cylindrical case 15. The target detection unit 43 of the rotation detection device 41 is attached to the outer circumferential surface of the end of the substrate portion 12Ba that protrudes from the cylindrical case 15.

[0087] A bottomed cylindrical cover member 45 is attached to the other axial side of the cylindrical case 15, covering the outer circumferential surface and end surface of the protruding portion of the substrate portion 12Ba in a non-contact manner. A detection target 42B is attached to the inner circumferential surface of the peripheral wall of the cover member 45. The detection target 42B is arranged in a semicircular shape along the inner circumferential 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 detection unit 43, which is attached to the outer peripheral surface of the substrate portion 12Ba, has its detection surface 43a facing the detection target 42B with a predetermined gap between them.

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

[0089] In this embodiment as well, the signal input from the rotation detection device 41 to the controller can be used by the controller to detect and address situations where the output of the assist signal (drive signal) to the motor 8 has stopped for some reason, or to correct discrepancies between the motor 8's output target and its actual rotation.

[0090] As described above, since the basic configuration of the speed reducer 411 of this embodiment is the same as that of the speed reducer 311 of the fourth embodiment, the same basic effects as those of the speed reducer 311 of the fourth embodiment can be obtained. However, in this embodiment, the gearbox 411 has a bottomed cylindrical cover member 45 attached to the other axial side of the cylindrical case 15, and the rotation detection device 41 is positioned between the outer circumferential surface of the substrate portion 12Ba on the base block 12 side and the inner circumferential surface of the cover member 45. Therefore, the cover member 45 prevents foreign matter such as iron powder from entering the vicinity 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 derived from the fourth and fifth embodiments described above are listed below. (1) A base block (for example, base block 12) and An input rotating body (e.g., a crankshaft 13) is rotatably supported on the base block and rotates by receiving power from a drive device (e.g., a motor 8), A reduction mechanism (for example, a first oscillating gear 14A, a second oscillating gear 14B, and an internal tooth pin 21) that reduces the rotation of the input rotating body, A cylindrical case (for example, cylindrical case 115) covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, A reduction gear comprising a rotation detection device (for example, a rotation detection device 41) for detecting the relative rotation state of the base block and the cylindrical case.

[0092] (2) The rotation detection device is A detection target (for example, detection targets 42, 42A) is installed on either the axial end face of the cylindrical case or the axial end face of the base block, The device has a target detection unit (for example, a target detection unit 43) installed on either the axial end face of the cylindrical case or the other of the axial end face of the base block, The gearbox according to (1), wherein the detection surface of the target detection unit (for example, the detection surface 43a) is arranged to face the detection target.

[0093] (3) The cylindrical case is fitted with a cover member (for example, a cover member 45) that covers the axial end of the cylindrical case. The rotation detection device is A detection target (e.g., detection target 42B) is installed on either the cover member or the axial end of the base block, The base block has a target detection unit (for example, a target detection unit 43) installed on either the cover member or the other end of the base block in the axial direction. The gearbox according to (1), wherein the detection surface of the target detection unit is arranged to face the detection target.

[0094] (4) Base block (for example, base block 12) and A crankshaft (e.g., crankshaft 13) having an eccentric rotating portion and rotatably supported on the base block, which receives power input from a drive device (e.g., motor 8), A rocking gear (for example, a first rocking gear 14A, a second rocking gear 14B) having external teeth on its outer circumference and receiving an eccentric rotational force from the eccentric rotating part, A cylindrical case (e.g., cylindrical case 15) having internal teeth (e.g., internal tooth pin 21) with a different number of teeth from the external teeth, which is rotatably supported on the base block and rotates in mesh with the external teeth, A reduction gear comprising a rotation detection device (for example, a rotation detection device 41) for detecting the relative rotation state of the base block and the cylindrical case.

[0095] (5) A drive device that outputs rotational power, The system includes a reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The aforementioned reduction gear is Base block and, An input rotating body that rotates by receiving power from a drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, A cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, A reduction gear unit comprising a rotation detection device for detecting the relative rotation state of the base block and the cylindrical case. (6) A drive device that outputs rotational power, A reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The steering mechanism operates by receiving power reduced by the aforementioned reduction gear, The aforementioned reduction gear is An input rotating body that rotates by receiving power from a drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, A cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, A steering assist device comprising a rotation detection device for detecting the relative rotation state of the base block and the cylindrical case.

[0096] <Sixth Embodiment> Figure 16 is a cross-sectional view of the drive unit 10 employing the reduction gear 511 of the sixth embodiment, and Figure 17 is a view of the reduction gear 511 as seen from arrow XII in Figure 16. The reduction gear 511 of this embodiment comprises a base block 12 fixed to the vehicle, a plurality of crankshafts 13 (input rotating bodies) rotatably supported by the base block 12, a first oscillating gear 14A and a second oscillating gear 14B that oscillate in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radially outer surfaces of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner circumferential surface of the cylindrical case 15, and an internal tooth pin 21 is held in the pin groove 20. The internal tooth pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes the reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0097] The base block 12 comprises a first base block 12A positioned at one end in the axial direction and a second base block 12B positioned at the other end in the axial direction. The second base block 12B has a connecting support column 12Bb that abuts against the base plate portion 12Aa of the first base block 12A, and in this state, the connecting support column 12Bb is fixed to the base plate portion 12Aa by bolts 16. Furthermore, a bolt insertion hole 40 that penetrates axially is formed in the fixing flange 12Ab that extends radially outward from the base plate portion 12Aa of the first base block 12A. Bolts for fixing the vehicle body (not shown) are inserted into the bolt insertion hole 40.

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

[0099] Between the outer circumferential surface of the substrate portion 12Aa of the first base block 12A and the inner circumferential surface of one axial end of the case body portion 15a, a sealing member 28 is positioned axially outward of the bearing 19 at one end, to seal the space between the substrate portion 12Aa and the case body portion 15a. Similarly, between the outer circumferential surface of the substrate portion 12Ba of the second base block 12B and the inner circumferential surface of the other axial end of the case body portion 15a, a sealing member 28 is positioned axially outward of the bearing 19 at the other end, to seal the space 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 fluid for lubricating mechanical operating parts such as the 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 positioned to cover the axially outer region of the sealing member 28 between the substrate portion 12Ba and the cylindrical case 15. Multiple heat dissipation fins 50 are integrally formed on the axially outer end face of the substrate 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 circumference 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 multiple layers with radial offsets (different diameters). These heat dissipation fins 50 can dissipate the heat transferred from inside the reduction gear 511 to the substrate portion 12Ba into the surrounding atmosphere. The radiating fin 50b and the outermost annular fin 50a are positioned at approximately the same diameter as the holding position of the internal tooth pin 21 inside the cylindrical case 15.

[0102] As described above, in the gearbox 511 of this embodiment, the output arm 27 extending radially outward from the outer circumferential surface of the cylindrical case 15 is integrally formed with the cylindrical case 15. Therefore, unlike the case in which a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to that flange, a stable torque can be output to the outside through the output arm 27 without increasing the overall size and weight of the gearbox 211 or increasing the manufacturing man-hours.

[0103] Furthermore, in this embodiment, the gearbox 511 has multiple heat dissipation fins 50 formed on the portion of the base block 12 that is exposed to the outside of the cylindrical case 15 (the end face of the substrate portion 12Ba). Therefore, the heat generated inside the gearbox 511 due to the operation of the reduction mechanism can be efficiently dissipated to the surroundings. Consequently, when this configuration is adopted, the temperature rise of the base block 12 and the cylindrical case 15 can be suppressed, and as a result, the rotational speed of the mechanical operating parts inside the gearbox 511 can be increased. The heat dissipation fins 50 can also be formed on the outer surface of the cylindrical case 15.

[0104] Other inventions that can be derived from the sixth embodiment described above are listed below. (1) Base block and, An input rotating body that rotates by receiving power from a drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, A gearbox in which heat dissipation fins are formed on the portion of the base block that is exposed to the outside of the cylindrical case.

[0105] (2) Base block and, A crankshaft having an eccentric rotating portion and rotatably supported on the base block, to which power is input from the drive device, A rocking gear having external teeth on its outer circumference and receiving an eccentric rotational force from the eccentric rotating part, The system comprises a cylindrical case having internal teeth with a different number of teeth from the external teeth, which is rotatably supported on the base block and rotates in mesh with the external teeth, A gearbox in which heat dissipation fins are formed on the portion of the base block that is exposed to the outside of the cylindrical case.

[0106] (3) A drive device that outputs rotational power, The system includes a reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The aforementioned reduction gear is Base block and, An input rotating body that rotates by receiving power from a drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, A drive unit having heat dissipation fins formed on the portion of the base block that is exposed to the outside of the cylindrical case.

[0107] (4) A drive device that outputs rotational power, A reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The steering mechanism operates by receiving power reduced by the aforementioned reduction gear, The aforementioned reduction gear is Base block and, An input rotating body that rotates by receiving power from a drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, A steering assist device having heat dissipation fins formed on the portion of the base block that is exposed to the outside of the cylindrical case.

[0108] <Seventh Embodiment> Figure 18 is a cross-sectional view of the drive unit 10 employing the reduction gear 611 of the seventh embodiment. The reduction gear 611 of this embodiment comprises a base block 12 fixed to the vehicle, a plurality of 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 in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radially outer sides of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner circumferential surface of the cylindrical case 15, and an internal tooth pin 21 is held in the pin groove 20. The internal tooth pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes the reduction mechanism. These basic configurations are the same as those of the first embodiment.

[0109] The base block 12 comprises a first base block 12A positioned at one end in the axial direction and a second base block 12B positioned at the other end in the axial direction. The second base block 12B has a connecting support column 12Bb that abuts against the base plate portion 12Aa of the first base block 12A, and in this state, the connecting support column 12Bb is fixed to the base plate portion 12Aa by bolts 16. Furthermore, a bolt insertion hole 40 that penetrates axially is formed in the fixing flange 12Ab that extends radially outward from the base plate portion 12Aa of the first base block 12A. Bolts for fixing the vehicle body (not shown) are inserted into the bolt insertion hole 40.

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

[0111] Between the outer circumferential surface of the substrate portion 12Aa of the first base block 12A and the inner circumferential surface of one axial end of the case body portion 15a, a sealing member 28 is positioned axially outward of the bearing 19 at one end, to seal the space between the substrate portion 12Aa and the case body portion 15a. Similarly, between the outer circumferential surface of the substrate portion 12Ba of the second base block 12B and the inner circumferential surface of the other axial end of the case body portion 15a, a sealing member 28 is positioned axially outward of the bearing 19 at the other end, to seal the space 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 fluid for lubricating mechanical operating parts such as the reduction gear mechanism.

[0112] Multiple crankshafts 13, which are output rotating bodies, 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 bearings 22 on the respective base portions 12Aa and 12Ba of the first base block 12A and the second base block 12B. Each crankshaft 13 has a pair of journal portions 13a formed axially spaced apart, and each of these journal portions 13a is supported by bearings 22. Two eccentric rotating 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 the bearing 22. The bearing 22 is assembled in the support holes 47 of the base plates 12Aa and 12Ba such that the rollers that contact the inner and outer rings are inclined radially outward toward the eccentric rotating portion 13b of the crankshaft 13.

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

[0114] A metal powder detection sensor 48 is mounted in one of the support holes 47 of the substrate portion 12Aa, 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 fluid inside the reduction gear 711. The metal powder detection sensor 48 is mounted on the side of the support hole 47 that is separated from the eccentric rotating portion 13b with the bearing 22 in between, and is positioned in the space between the mounting surface on the support hole 47 side and the outer circumferential surface of the journal portion 13a on the crankshaft 13 side. The metal powder detection sensor 48 is fixed to the substrate portion 12Aa by press-fitting into the support hole 47 or by screwing it in.

[0115] The metal powder detection sensor 48 can be, for example, one that has a permanent magnet for attracting iron powder in a gap 48b in the sensor block 48a through which lubricating fluid can flow, and detects the amount of iron powder attracted by the magnetic force of the permanent magnet from the change in electrical resistance in the circuit. However, 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 fluid.

[0116] The metal powder detection sensor 48 is electrically connected to the input 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 fluid in the gearbox 711 is equal to or greater than a specified amount. If the controller determines that the amount of metal powder mixed in is equal to or greater than a specified amount, it notifies the user that it is time to perform maintenance such as changing the lubricating fluid by illuminating a warning indicator.

[0117] As described above, in the gearbox 711 of this embodiment, the output arm 27 extending radially outward from the outer circumferential surface of the cylindrical case 15 is integrally formed with the cylindrical case 15. Therefore, unlike the case in which a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to that flange, a stable torque can be output to the outside through the output arm 27 without increasing the overall size and weight of the gearbox 711 or increasing the manufacturing man-hours.

[0118] Furthermore, in this embodiment, the reduction gear 711 has a metal powder detection sensor 48 for detecting metal powder mixed in the lubricating fluid, which is positioned axially apart from the reduction mechanism (first oscillating gear 14A and second oscillating gear 14B). Therefore, the amount of metal powder mixed in the lubricating fluid can be detected in a portion away from the area where the lubricating fluid is greatly agitated by the operation of the reduction mechanism. When the reduction gear 711 of this embodiment is adopted, the problem of not being able to accurately detect the amount of metal powder mixed in due to the great agitation of the lubricating fluid by the operation of the reduction mechanism can be solved. In addition, when the reduction gear 711 of this embodiment is adopted, even if the agitation of the lubricating fluid by the reduction mechanism changes due to differences in the specifications of the reduction gear 711, the amount of metal powder mixed in can be accurately detected.

[0119] In particular, in the gearbox 711 of this embodiment, the metal powder detection sensor 48 is located near the journal portion 13a of the crankshaft 13, so it is less susceptible to the effects of agitation of the lubricating fluid due to the operation of the eccentric rotating portion 13b of the crankshaft 13.

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

[0121] Other inventions that can be derived from the seventh embodiment described above are listed below. (1) A base block (for example, base block 12) and An input rotating body (e.g., a crankshaft 13) is rotatably supported on the base block and rotates by receiving power from a drive device (e.g., a motor 8), A reduction mechanism (for example, a first oscillating gear 14A, a second oscillating gear 14B, and an internal tooth pin 21) that reduces the rotation of the input rotating body, A cylindrical case (for example, cylindrical case 115) covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The system includes a metal powder detection sensor (for example, a metal powder detection sensor 48) that detects metal powder in the lubricating fluid filled in the space surrounded by the cylindrical case and the base block, The metal powder detection sensor is located near the bearing portion (for example, the journal portion 13a) of the input rotating body, which is positioned at a distance from the reduction mechanism portion in the axial direction. (2) A base block (for example, base block 12) and A crankshaft (e.g., crankshaft 13) having an eccentric rotating portion and rotatably supported on the base block, which receives power input from a drive device (e.g., motor 8), A rocking gear (for example, a first rocking gear 14A, a second rocking gear 14B) having external teeth on its outer circumference and receiving an eccentric rotational force from the eccentric rotating part, A cylindrical case (e.g., cylindrical case 15) having internal teeth (e.g., internal tooth pin 21) with a different number of teeth from the external teeth, which is rotatably supported on the base block and rotates in mesh with the external teeth, The system includes a metal powder detection sensor (for example, a metal powder detection sensor 48) that detects metal powder in the lubricating fluid filled in the space surrounded by the cylindrical case and the base block, The metal powder detection sensor is located in the vicinity of the journal portion (for example, journal 13b) of the crankshaft in the gearbox. (3) The base block has support holes (e.g., support holes 47) that support the journal portion via bearings (e.g., bearing 22), The gearbox according to claim 2, wherein the metal powder detection sensor is fixed within the support hole. (4) A drive device that outputs rotational power, The system includes a reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The aforementioned reduction gear is Base block and, An input rotating body that rotates by receiving power from a drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, A cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The system includes 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 located near the bearing portion of the input rotating body, which is positioned axially separated from the reduction mechanism.

[0122] (5) A drive device that outputs rotational power, A reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The steering mechanism operates by receiving power reduced by the aforementioned reduction gear, The aforementioned reduction gear is Base block and, An input rotating body that rotates by receiving power from a drive device while being rotatably supported on the base block, A reduction mechanism for reducing the rotation of the input rotating body, A cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The system includes 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 steering assist device positioned near the bearing portion of the input rotating body, which is located at a position axially separated from the reduction mechanism.

[0123] <Eighth Embodiment> Figure 19 is a diagram showing a vertical cross-section of the drive unit 10 employing the reduction gear 711 of the eighth embodiment. The reduction gear 711 of this embodiment comprises a base block 12 fixed to the vehicle, a plurality of 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 in response to the rotation of the crankshafts 13, and a cylindrical case 15 that covers the radially outer sides of the first oscillating gear 14A and the second oscillating gear 14B. A pin groove 20 is formed on the inner circumferential surface of the cylindrical case 15, and an internal tooth pin 21 is held in the pin groove 20. The internal tooth pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes the reduction mechanism. These basic configurations are the same as those of the first embodiment.

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

[0125] The second base block 12B has its connecting column 12Bb end face abutted against the base plate portion 12Aa of the first base block 12A, and each connecting column 12Bb is fixed to the first base block 12A by fitting together with tapered pins 57. The tapered pins 57 are fitted into the base plate portion 12Aa and the connecting column 12Bb from the base plate portion 12Aa side of the first base block 12A.

[0126] The first oscillating gear 14A and the second oscillating gear 14B have multiple relief holes 18 through which each connecting column 12Bb of the first base block 12A passes. The relief holes 18 are formed to be sufficiently larger than the outer surface shape of each connecting column 12Bb so that each connecting column 12Bb does not obstruct the oscillating rotation of the first oscillating gear 14A and the second oscillating gear 14B.

[0127] Furthermore, a connecting shaft 55 is formed at the radial center of the substrate portion 12Ba of the second base block 12B, extending toward the substrate portion 12Aa of the first base block 12A. The connecting shaft 55 is formed with a larger diameter than the tapered pin 57 that is fitted into the connecting column 12Bb. In contrast, at the radial center of the substrate portion 12Aa of the first base block 12A, an insertion hole 58 into which the tip of the connecting shaft 55 is inserted, and a substantially circular recess 59 that passes through the insertion hole 58 and is positioned where the tip of the connecting shaft 55 is located are formed. A nut 56 is placed in the recess 59 to be tightened onto the tip of the connecting shaft 55 that passes through the insertion hole 58. The nut 56, when tightened onto the tip of the connecting shaft 55, fixes the first base block 12A and the second base block in the axial direction. It is desirable that the nut 56 used here has a loosening prevention function. In this embodiment, the nut 56 constitutes a pull-out prevention member.

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

[0129] As described above, in the gearbox 811 of this embodiment, the output arm 27 extending radially outward from the outer circumferential surface of the cylindrical case 15 is integrally formed with the cylindrical case 15. Therefore, unlike the case in which a fixing flange is provided on the cylindrical case 15 and a separate output arm is bolted to that flange, a stable torque can be output to the outside through the output arm 27 without increasing the overall size and weight of the gearbox 811 or increasing the manufacturing man-hours.

[0130] Furthermore, in this embodiment, the gearbox 711 has a connecting shaft 55 that protrudes from the radial center 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 tightened onto the tip of the connecting shaft 55, thereby fixing the first base block 12A and the second base block 12B in the axial direction. Multiple connecting support columns 12Bb protruding 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 gearbox 711 of this embodiment, the axial fixing (displacement restriction) and rotational fixing (displacement restriction) of the first base block 12A and the second base block 12B can be divided between the central connecting shaft 55 and nut 56 and the multiple tapered pins 57 connected to each connecting column 12Bb. Consequently, when the gearbox 711 of this embodiment is adopted, the external size of the connecting columns 12Bb can be made smaller compared to when each connecting column 12Bb and the second base block are connected with multiple bolts, and the number of parts required for fixing can be reduced. Furthermore, because the external size of the connecting columns 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 and 14B.

[0132] Other inventions that can be derived from the eighth embodiment described above are listed below. (1) A first base block (e.g., first base block 12A) and a second base block (e.g., first base block 12A) are interconnected at multiple points around the central axis via connecting support columns 12Bb, The connecting support column has a relief hole through which it passes, and the oscillating gear is supported by the first base block and the second base block so as to be able to swing and rotate, The system comprises a cylindrical case that transmits rotation reduced in speed from the aforementioned oscillating gear, The first base block and the second base block are fixed in the axial direction by a connecting shaft that protrudes from the radial center of one of them and passes through the other, and a pull-out restricting member fixed to the connecting shaft that passes through the other. The connecting support column is integrally formed with either the first base block or the second base block. The tip of the connecting support column is fixed to the other of the first base block and the second base block by fitting with a pin (for example, a tapered pin 57) in the reduction gear.

[0133] (2) A first base block (e.g., first base block 12A) and a second base block (e.g., first base block 12A) are interconnected at multiple points around the central axis via connecting pillars (e.g., connecting pillars 12Bb), A crankshaft (e.g., crankshaft 13) having an eccentric rotating part (e.g., eccentric rotating part 13b) and being rotatably supported by the first base block and the second base block, and receiving power input from a drive device (e.g., motor 8), The connecting support has a relief hole (for example, relief hole 18) through which it passes, and has external teeth (for example, external teeth 14Aa, 14Bb) on its outer circumference, and is an oscillating gear (for example, first oscillating gear 14A, second oscillating gear 14B) that receives an eccentric rotational force from the eccentric rotating part and rotates in an oscillating manner, The device comprises a cylindrical case (e.g., cylindrical case 15) having internal teeth (e.g., internal tooth pin 21) with a different number of teeth from the external teeth, which is rotatably supported on the base block and rotates in mesh 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 the radial center of one of them and passes through the other, and a pull-out restricting member (e.g., nut 56) fixed to the connecting shaft that passes through the other. The connecting support column is integrally formed with either the first base block or the second base block. The tip of the connecting support column is fixed to the other of the first base block and the second base block by fitting with a pin (for example, a tapered pin 57) in the reduction gear.

[0134] (3) A drive device that outputs rotational power, The system includes a reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The aforementioned reduction gear is A first base block and a second base block, in which multiple points around the central axis are interconnected via connecting columns, The connecting support column has a relief hole through which it passes, and the oscillating gear is supported by the first base block and the second base block so as to be able to swing and rotate, The system comprises a cylindrical case that transmits rotation reduced in speed from the aforementioned oscillating gear, The first base block and the second base block are fixed in the axial direction by a connecting shaft that protrudes from the radial center of one of them and passes through the other, and a pull-out restricting member fixed to the connecting shaft that passes through the other. The connecting support column is integrally formed with either the first base block or the second base block. The tip of the connecting support column is a drive unit fixed to either the first base block or the second base block by a pin fitting.

[0135] (4) A drive device that outputs rotational power, A reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The steering mechanism operates by receiving power reduced by the aforementioned reduction gear, The aforementioned reduction gear is A first base block and a second base block, in which multiple points around the central axis are interconnected via connecting columns, The connecting support column has a relief hole through which it passes, and the oscillating gear is supported by the first base block and the second base block so as to be able to swing and rotate, The system comprises a cylindrical case that transmits rotation reduced in speed from the aforementioned oscillating gear, The first base block and the second base block are fixed in the axial direction by a connecting shaft that protrudes from the radial center of one of them and passes through the other, and a pull-out restricting member fixed to the connecting shaft that passes through the other. The connecting support column is integrally formed with either the first base block or the second base block. The tip of the connecting support column is fixed to the other of either the first base block or the second base block by a pin fitting, providing a steering assistance device.

[0136] It should be noted that the present invention is not limited to the embodiments described above, and various design modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0137] 1... Steering assist device, 6... Steering mechanism, 8... Motor (drive device), 10... Drive unit, 11... Reducer, 12... Base block, 13... Crankshaft (input rotating body), 14A... First oscillating gear (oscillating gear, reduction mechanism), 14B... Second oscillating gear (oscillating gear, reduction mechanism), 15... Cylindrical case, 21... Internal tooth pin (internal tooth, reduction mechanism), 27... Output arm.

Claims

1. An input rotating body having a crank gear attached to a crankshaft and meshing with the output gear of a drive device, which rotates by receiving power from the drive device, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The reduction mechanism comprises a base block that rotatably supports the input rotating body and the cylindrical case, and has a fixed flange that is fixed to the case of the drive device. The axial edges on both sides of the cylindrical case are rotatably supported by the base block via bearings. The cylindrical case has an output arm integrally formed thereon, which extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. reducer.

2. A base block having a fixing flange that is fixed to the case of the drive unit, A crankshaft having an eccentric rotating portion and rotatably supported on the base block, to which power is input from the drive device, A rocking gear having external teeth on its outer circumference and receiving an eccentric rotational force from the eccentric rotating part, The system comprises a cylindrical case having internal teeth with a different number of teeth from the external teeth, which is rotatably supported on the base block and rotates in mesh with the external teeth, The crankshaft has a crank gear that meshes with the output gear of the drive unit. The axial edges on both sides of the cylindrical case are rotatably supported by the base block via bearings. The cylindrical case has an output arm integrally formed thereon, which extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. reducer.

3. A drive unit having an output gear that outputs rotational power, The system includes a reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The aforementioned reduction gear is An input rotating body that is mounted on a crankshaft and has a crank gear that meshes with the output gear, and rotates by receiving power from the drive device, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The reduction mechanism comprises a base block that rotatably supports the input rotating body and the cylindrical case, and has a fixed flange that is fixed to the case of the drive device. The axial edges on both sides of the cylindrical case are rotatably supported by the base block via bearings. The cylindrical case has an output arm integrally formed thereon, which extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. Drive unit.

4. A drive unit having an output gear that outputs rotational power, A reduction gear that receives power from the aforementioned drive device and reduces the input rotation, The steering mechanism operates by receiving power reduced by the aforementioned reduction gear, The aforementioned reduction gear is An input rotating body that is mounted on a crankshaft and has a crank gear that meshes with the output gear, and rotates by receiving power from the drive device, A reduction mechanism for reducing the rotation of the input rotating body, The system comprises a cylindrical case that covers the outside of the reduction mechanism and rotates by receiving the power reduced by the reduction mechanism, The reduction mechanism comprises a base block that rotatably supports the input rotating body and the cylindrical case, and has a fixed flange that is fixed to the case of the drive device. The axial edges on both sides of the cylindrical case are rotatably supported by the base block via bearings. The cylindrical case has an output arm integrally formed thereon, which extends radially outward from the outer surface of the cylindrical case and transmits operating force to the outside. Steering assist device.

Images