Steering device

Abstract

The invention provides a steering device. A steering device according to one embodiment of the present invention is provided with: a first gear mechanism to which rotation of a steering wheel operation is input, which converts the direction of the rotation, and which outputs the rotation as a primary rotation; and a second gear mechanism to which the primary rotation output from the first gear mechanism is input, and which decelerates and outputs the primary rotation. The first gear mechanism is provided with: a switching mechanism member that switches the direction of rotation; and a housing part which accommodates the conversion mechanism component. The second gear mechanism is provided with: a speed reduction mechanism member for reducing the speed of the primary rotation; an output shaft that decelerates and outputs the primary rotation; and a gear housing that accommodates the speed reduction mechanism member. The gear housing is provided with a flange portion forming a side portion of the gear housing in an axial direction facing the output shaft. The flange portion and the housing portion are integrally formed with each other.

Description

TECHNICAL FIELD

[0001] The present application relates to a steering device. BACKGROUND

[0002] Conventionally, an electric power steering system is known. The electric power steering system imparts a driving force of an electric motor to a steering mechanism of a vehicle in addition to a steering wheel operation force of a driver, thereby reducing the steering wheel operation force of the driver. A steering device used in the electric power steering system imparts the driving force of the electric motor to an output portion coupled to the steering mechanism on the wheel side while transmitting the steering wheel operation force to the output portion via a speed reducer (see, for example, Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: European Patent No. 3347258 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the steering device of Patent Literature 1, it is desirable to have a structure in which the working accuracy and reliability are improved by accurately determining the relative positions of an input mechanism that converts the direction of rotation of a steering wheel operation and outputs the rotation, a speed reducer, and a driving device such as an electric motor.

[0008] One object of the present application is to achieve improvement in working accuracy and reliability of a steering device used in a steering system of a vehicle.

[0009] SOLUTION TO PROBLEM

[0010] (1) A steering device according to one aspect of the present application includes: a first gear mechanism that is input with rotation of a steering wheel operation, converts the direction of the rotation, and outputs the rotation as primary rotation; and a second gear mechanism that is input with the primary rotation output from the first gear mechanism, reduces the primary rotation, and outputs the primary rotation. The first gear mechanism includes a conversion mechanism member that converts the direction of the rotation, and a housing portion that houses the conversion mechanism member. The second gear mechanism includes a reduction mechanism member that reduces the primary rotation, an output shaft that reduces and outputs the primary rotation, and a gear housing that houses the reduction mechanism member. A flange portion that forms a side portion of the gear housing toward an axial direction of the output shaft is provided in the gear housing. The flange portion and the housing portion are integrally formed with each other.

[0011] According to the structure, the flange portion of the gear housing of the second gear mechanism, which faces the axial direction, and the housing portion of the first gear mechanism are integrally formed with each other. Thus, the number of components can be reduced to achieve weight reduction. Also, the accuracy of the relative positions of the first gear mechanism and the second gear mechanism can be improved to achieve improved work accuracy.

[0012] (2) In the steering apparatus of one aspect of the present application, the steering apparatus includes a plurality of fasteners that fix the housing main body of the gear housing to the flange portion, and a gasket plate that is disposed between the flange portion and the plurality of fasteners, and is fixed between the seating surfaces of the plurality of fasteners and the flange portion by screwing in of the plurality of fasteners. The gasket plate is formed to a size that allows the seating surfaces of at least two of the plurality of fasteners to contact.

[0013] According to the structure, the gasket plate for fastening the housing main body of the second gear mechanism to the flange portion is formed to a size that spans the seating surfaces of the plurality of fasteners. Thus, compared to a case where a separate gasket is provided for each fastener, the region of the gasket plate between the fasteners can be brought into contact with the flange portion. Thus, the surface pressure applied to the flange portion by screwing in of the fasteners is reduced. As a result, even in a case where the flange portion is formed of a light metal having a lower hardness, deformation of the seating surface side of the flange portion can be suppressed and the screwing-in torque of each fastener can be ensured, so that improved reliability can be achieved.

[0014] (3) In the steering apparatus of one aspect of the present application, the steering apparatus includes a drive device that has a drive shaft that outputs a driving force that assists in operation of the steering wheel. A controller is provided at one end portion of the drive device, and is configured to overlap the drive device in the axial direction of the drive shaft and control driving of the drive device. The controller is formed in a flat shape having an outer diameter larger than that of the drive device when viewed in the axial direction of the drive shaft, so that the thickness of the drive device in the axial direction of the drive shaft is suppressed.

[0015] According to the structure, the controller provided at one end portion of the drive device in a manner that overlaps the drive shaft in the axial direction of the drive shaft can be formed in a flat shape having an outer diameter larger than that of the drive device when viewed in the axial direction of the drive shaft. Thus, the thickness of the drive device including the controller in the axial direction can be suppressed, and the size of the controller can be ensured, so that improved reliability can be achieved.

[0016] Effects of the Invention

[0017] According to the present application, improved work accuracy and reliability of a steering apparatus used in a steering system of a vehicle can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0018] FIG. 1Ais a schematic configuration view of a steering assist device of a right-hand drive vehicle employing the steering unit of the present embodiment.

[0019] FIG. 1B is a schematic configuration view of a steering assist device of a left-hand drive vehicle employing the steering unit of the present embodiment.

[0020] FIG. 2 is a perspective view of the steering unit of the present embodiment.

[0021] FIG. 3 is a perspective view of the steering unit of the present embodiment, viewed from a different direction than FIG. 2

[0022] FIG. 4 is a view of the steering unit, viewed from the axial direction of the operation input shaft.

[0023] FIG. 5 is a view of the steering unit, viewed from the axial direction of the output shaft.

[0024] FIG. 6 is a sectional view of the first gear mechanism along the VI-VI line of FIG. 4

[0025] FIG. 7 is a view of the respective mechanism components of the first gear mechanism and the second gear mechanism of the steering unit, viewed from the axial direction of the output shaft.

[0026] FIG. 8 is a sectional view of the first gear mechanism, the second gear mechanism, and the drive device along the VIII-VIII line of FIG. 5

[0027] FIG. 9 is a perspective view showing the housing-flange formed product and the gasket plate.

[0028] FIG. 10A is a perspective view showing a state in which the conversion mechanism component of the first gear mechanism is separated from the housing portion.

[0029] FIG. 10B is a perspective view showing a state in which the housing-flange member is flipped over in the first axial direction with respect to FIG. 10A

[0030] FIG. 11 is a view of the steering unit, viewed from the second axial direction, showing a modification example of the arrangement of the drive device.

[0031] FIG. 12A is a perspective view showing a first modification example of the arrangement of the controller.

[0032] FIG. 12B ​​​​is a perspective view showing a second modification example of the controller.

[0033] Reference Signs Description

[0034] 1, steering assist device; 3, steering shaft; 10, steering unit (steering device); 11, first gear mechanism; 1 Id, conversion mechanism part; 12, housing part; 13, operation input shaft (first input shaft); 16, first output shaft; 16c, oil seal (sealing member); 17, first output gear; 19, sensor; 20, second gear mechanism; 21, gear housing; 21d, bearing; 22, first housing; 25, second output shaft (output shaft); 37, flange part; 37c1, O-ring (second sealing member); 37d, bearing; 39, washer plate; 45, second input shaft (input shaft); 45c, oil seal (second sealing member); 46, second input gear; 47, shaft part; 56, transmission gear; 56a, operation-side transmission gear (primary input gear); 65, drive device; 67, drive shaft; 68, controller (control device); 70, transmission mechanism; 71, transmission housing; 72a, cover part; 72c, bulging part; 73, housing cover; 75, drive pulley (first pulley); 76, driven pulley (second pulley); 76a, driven pulley support shaft (second pulley support shaft); 76b, transmission output shaft; 76c, transmission output gear; 77, transmission belt; A2, A3, outer shape; B2, fastener; F1, first axial direction; F2, second axial direction; F3, third direction (cross direction); H2, width; K2, separation space; K3, second separation space; R1, oil chamber; S1, imaginary plane. DETAILED DESCRIPTION

[0035] Hereinafter, a mode for carrying out the present application will be described with reference to the drawings. However, the present application is not limited to only this embodiment.

[0036] <Steering assist device 1>

[0037] FIG. 1A is a schematic configuration view of the steering assist device 1 of a vehicle to the right of which the steering unit (steering device) 10 of this embodiment is adopted. FIG. 1B is a schematic configuration view of the steering assist device 1 of a vehicle to the left of which the steering unit 10 of this embodiment is adopted. CL indicates the center of the vehicle left and right. Arrow LH indicates the vehicle left side. Arrow RH indicates the vehicle right side.

[0038] As shown in FIG. 1A , FIG. 1B , the steering assist device 1 is provided with a steering wheel 2, a steering shaft (column shaft) 3, a steering unit 10, and a steering mechanism 6.

[0039] The steering wheel 2 is disposed in front of a driver's seat of the vehicle, and is rotated by the driver.

[0040] The steering shaft 3 is coupled to the steering wheel 2 so as to be rotatable integrally with the steering wheel 2, and extends downward of the steering wheel 2. A steering operation force (steering torque) is input from the steering wheel 2 to the steering shaft 3. The steering unit 10 is coupled to a top end portion (lower end portion) of the steering shaft 3. The steering mechanism 6 is operated by at least one of the steering torque and an assist torque described later by means of the steering unit 10.

[0041] The steering unit 10 has an output shaft 25 (refer to FIG. 2 、 FIG. 3 ). The output arm 7 is provided to the output shaft 25. A top end portion of the output arm 7 is coupled to the steering mechanism 6 of the vehicle. The steering mechanism 6 has an operation arm 6a that receives an output from the output arm 7, and a tie rod 6b that steers the left and right front wheels W of the vehicle in accordance with an operation of the operation arm 6a. The output arm 7 is swung by the output shaft 25 of the steering unit 10 outputting at least one of the steering torque and the assist torque. Thereby, the output arm 7 operates the steering mechanism 6 to steer the left and right front wheels W of the vehicle.

[0042] <Steering unit 10>

[0043] FIG. 2 is a perspective view of the steering unit 10 of the present embodiment. FIG. 3 is a perspective view of the steering unit 10 of the present embodiment as viewed from a direction different from FIG. 2 .

[0044] As shown in FIG. 2 、 FIG. 3 , the steering unit 10 has a first gear mechanism 11, a second gear mechanism 20, and a drive device 65.

[0045] The first gear mechanism 11 is an operation mechanism coupled to the steering shaft 3. The first gear mechanism 11 converts a rotational motion of the steering shaft 3 about a central axis C1 (first axis) into a rotational motion about an orthogonal axis C1a orthogonal to the first axis C1. The orthogonal axis C1a is disposed in parallel to a central axis (second axis) C2 of the output shaft 25 described later.

[0046] Hereinafter, a direction parallel to the first axis C1 is defined as a first axial direction, and a direction parallel to the orthogonal axis C1a and the second axis C2 is defined as a second axial direction. In each drawing, an arrow F1 indicates the first axial direction. An arrow F2 indicates the second axial direction. An arrow F3 indicates a third direction (cross direction) orthogonal to the first axial direction and the second axial direction.

[0047] Further, (+fl) indicates one side along the first axial direction Fl, and (-fl) indicates the other side along the first axial direction Fl. (+f2) indicates one side along the second axial direction F2, and (-f2) indicates the other side along the second axial direction F2. (+f3) indicates one side along the third direction F3, and (-f3) indicates the other side along the third direction F3.

[0048] The second gear mechanism 20 is a speed reducer. The first rotation centered on the orthogonal axis C la output from the first gear mechanism 11 is input to the second gear mechanism 20. The second gear mechanism 20 transmits the first rotation while reducing the speed of the first rotation, and outputs the first rotation as a second rotation from an output shaft 25 parallel to the second axial direction F2. Further, the second axial direction F2 can be defined as a unit axial direction.

[0049] The first gear mechanism 11 is disposed adjacent to the second gear mechanism 20 at a position on one side (+f3) of the third direction F3 from the second gear mechanism 20. The drive device 65 is disposed adjacent to the second gear mechanism 20 at a position on the other side (-f3) of the third direction F3 from the second gear mechanism 20.

[0050] The drive device 65 is a rotary electric machine. The drive device 65 includes a cylindrical main body portion 66 and a drive shaft 67 (see FIG. 2) protruding outward from an end portion on the axial direction of the main body portion 66. FIG. 2 The drive shaft 67 is disposed so as to be parallel to the second axial direction F2 in the axial direction (hereinafter defined as a drive axial direction). Therefore, the center axis (drive axis) C3 of the drive shaft 67 is parallel to the second axial direction F2. The drive force of the drive device 65 is reduced by the second gear mechanism 20 and transmitted to the steering mechanism 6. Also, the drive force of the drive device 65 is reduced by the transmission mechanism 70 described later and input to the second gear mechanism 20.

[0051] In the present embodiment, by increasing the reduction ratio of the transmission mechanism 70, the generated torque of the drive device 65 is suppressed, and the drive device 65 is downsized. For example, when viewed from the second axial direction F2, the outer shape A3 (see FIG. 2) of the drive device 65 is formed to be smaller in diameter than the outer shape A2 (see FIG. 2) of the second gear mechanism 20. FIG. 5 FIG. 5

[0052] A controller (control device) 68, for example, elongated circular in shape and longer in the first axial direction Fl, is provided at the other end portion in the axial direction of the drive device 65.

[0053] ​​The controller 68 has an electronic control device and a drive circuit for controlling the operation of the drive unit 65. The controller 68 is formed in a flat shape to suppress thickness along the drive axis. When viewed from the drive axis, the controller 68 is larger than the main body 66. The controller 68 has a housing portion 68a forming the exterior of the controller 68 and two drive circuits 68b and 68c (see reference) divided along the first axis F1 within the housing portion 68a. FIG. 5 Each drive circuit 68b and 68c cooperates to control the drive of the drive device 65. Moreover, even if one of the drive circuits 68b and 68c fails, the drive device 65 can be driven by the other alone, for example, generating about half of the normal output.

[0054] The driving force of the drive unit 65 is transmitted via the belt transmission mechanism 70 to the output shaft 25 and input shaft 45 of the second gear mechanism 20 (see reference). FIG. 7 , FIG. 8 The input shaft 45 and the output shaft 25 are configured coaxially. Furthermore, the input shaft 45 is sometimes referred to below as the second input shaft 45. A steering torque, whose rotational direction has been converted by the first gear mechanism 11, is also input to the second input shaft 45 of the second gear mechanism 20.

[0055] The first gear mechanism 11, the second gear mechanism 20, and the drive device 65 are arranged in a third direction F3 (arrangement direction) orthogonal to the first axis F1 and the second axis F2.

[0056] FIG. 4 This is a diagram showing the steering unit 10 viewed from the axial direction of the operating input shaft 13.

[0057] like FIG. 4 As shown, on the second axial direction F2, the width H3 of the main part of the drive device 65 and the width H1 of the main part of the first gear mechanism 11 are located within the width H2 of the main part of the second gear mechanism 20.

[0058] Furthermore, width H1 is the width of the portion excluding the local protrusions. Width H2 is the width of the portion excluding the locally protruding output shaft 25, etc. Width H3 is the width of the portion excluding the locally protruding drive shaft 67, etc. Each width H1, H2, and H3 is, for example, set to be the width within the range from the side 37a2 of the flange portion 37 located on one side (+f2) of the second axis F2 (described later) to the top end of the other side (-f2) of the second axis F2.

[0059] Thus, the first gear mechanism 11 (operation mechanism) that converts the direction of the rotation of the steering wheel operation, the second gear mechanism (reducer) 20 that decelerates the output of the first gear mechanism 11, and the drive device 65 (rotary electric machine) that imparts an assist torque that assists the steering wheel operation are arranged to overlap each other along the second axial direction F2 of the second gear mechanism 20.

[0060] Thus, it is possible to suppress the thickness in the second axial direction F2 of the steering unit 10, and therefore it is easy to arrange the steering unit 10 in the limited arrangement space in the vehicle.

[0061] Further, in the present embodiment, a structure in which the first gear mechanism 11 as a whole and the drive device 65 as a whole are arranged within the range of the width H2 of the second gear mechanism 20 along the second axial direction F2 is described. However, the present application is not limited to this case, and for example, a structure in which at least a part of each of the first gear mechanism 11 and the drive device 65 is arranged within the range of the width H2 of the second gear mechanism 20 along the second axial direction F2 can be adopted.

[0062] The steering torque that is transmitted from the steering wheel 2 to the steering shaft 3 is input to the input of the second gear mechanism 20 via the first gear mechanism 11. The steering torque is input from the first gear mechanism 11 to the input of the second gear mechanism 20, and the assist torque is input from the drive device 65 to the input of the second gear mechanism 20. The input of the second gear mechanism 20 includes the second input shaft 45 and a plurality of transmission gears 56. The second gear mechanism 20 synthesizes the steering torque and the assist torque that are input from the dual system (the first gear mechanism 11 and the drive device 65), and transmits the synthesized torque while decelerating it with the gear portion 40 (refer to FIG. 7 ). Thus, the synthesized torque of the steering torque and the assist torque is decelerated at a predetermined deceleration ratio and output to the output of the second gear mechanism 20 (output shaft 25).

[0063] When the drive device 65 fails, the steering torque is decelerated and output by the second gear mechanism 20 in a state in which the assist torque is 0 or reduced.

[0064] <First gear mechanism 11>

[0065] FIG. 5 is a view when the steering unit 10 is viewed from the axial direction of the output shaft 25. FIG. 6 is a sectional view along the VI-VI line of FIG. 4 , and shows the cross section of the first gear mechanism 11. FIG. 7 is a view when each of the mechanism components of the first gear mechanism 11 and the second gear mechanism 20 of the steering unit 10 is viewed from the axial direction of the output shaft 25. FIG. 8 is a sectional view along the VII-VII line of FIG. 5The cross-sectional view along line VIII-VIII shows the cross-section of the first gear mechanism 11, the second gear mechanism 20, and the drive device 65.

[0066] like FIG. 2 to FIG. 8 As shown, the first gear mechanism 11 includes a housing portion 12, an operation input shaft 13, a first bevel gear (first conical gear) 14, a second bevel gear (second conical gear) 15, a first output shaft 16, and a first output gear 17.

[0067] In this embodiment, the mechanism components including the operation input shaft 13, the first output shaft 16, the first bevel gear 14, the second bevel gear 15, and the first output gear 17 are collectively referred to as the conversion mechanism component 11d.

[0068] The housing portion 12 is integrally formed on the unit housing 10c. The unit housing 10c includes a gear housing 21 that houses the reduction mechanism components 20d, such as gears, in the second gear mechanism 20. Furthermore, the unit housing 10c functions as the overall frame of the steering unit 10. The housing portion 12 is formed into a cylindrical shape extending along the first axial direction F1.

[0069] The end (opening) of the housing portion 12 located on one side (+f1) along the first axial direction F1 corresponds to the upper end of the housing portion 12 located on the steering shaft 3 side. A first plug body 12a is installed at this end of the housing portion 12. Thus, the housing portion 12 is closed by the first plug body 12a.

[0070] The first shaft portion 13a of the operation input shaft 13, located on one side (+f1) of the first axial direction F1, is supported on the first plug body 12a by a pair of bearings 12b. The operation input shaft 13 is divided into three parts from one side (+f1) of the first axial direction F1 toward the other side (-f1) of the first axial direction F1, in the order of first shaft portion 13a, second shaft portion 13b, and third shaft portion 13c. Moreover, the second shaft portion 13b is divided into a first segment 13b1 located on one side (+f1) of the first axial direction F1 and a second segment 13b2 located on the other side (-f1) of the first axial direction F1.

[0071] The end (opening) of the housing portion 12 on the other side (-f1) along the first axial direction F1 corresponds to the lower end of the housing portion 12 on the steering mechanism 6 side. A second plug body 12c is mounted at this end of the housing portion 12. Thus, the housing portion 12 is closed by the second plug body 12c. The third shaft portion 13c of the operating input shaft 13 is supported by the second plug body 12c via a pair of bearings 12d.

[0072] A bottomed cylindrical protrusion 12e is integrally formed on one side (+f2) of the housing portion 12 located on the second axis F2 orthogonal to the first axis F1 (the portion located on the transmission mechanism 70 side described later). The protrusion 12e opens toward the side (+f2) on the second axis F2.

[0073] At the protrusion 12e, a cover 72a, described later, is installed from one side (+f2) along the second axis F2. Thus, a defined internal space K1 is formed inside the protrusion 12e. The internal space K1 houses a first output shaft 16 along the second axis F2, a pair of bearings 16b supporting the first output shaft 16, and a cylindrical support 18 supporting the pair of bearings 16b.

[0074] A bottomed cylindrical socket portion 13as is formed in the portion of the first shaft portion 13a located on the other side (-f1) of the first axial direction F1, which opens toward the other side (-f1) of the first axial direction F1. A portion of the second shaft portion 13b located on the other side (+f1) of the first axial direction F1 is inserted into the socket portion 13as, and the two are connected in a manner that allows them to rotate as a whole by means of spline engagement or the like.

[0075] The portion of the second shaft portion 13b located on the other side (-f1) of the first axial direction F1 has a bottomed cylindrical socket portion 13bs that opens toward the other side (-f1) of the first axial direction F1. The portion of the third shaft portion 13c located on the first axial direction F1 (+f1) is inserted into the socket portion 13bs, and the two are connected in a manner that allows them to rotate as a single unit by means of spline engagement or the like.

[0076] The first segment 13b1 and the second segment 13b2 of the second shaft portion 13b are both hollow. A torsion bar 13b3 extending along the first axis C1 passes through the interior of the first segment 13b1 and the second segment 13b2. The first segment 13b1 and the second segment 13b2 rotate as a unit by means of the torsion bar 13b3, and generate relative rotation by an amount corresponding to the torsional deformation of the torsion bar 13b3.

[0077] A sensor 19 is provided on the outer periphery of the second shaft portion 13b to detect the relative rotation of the first segment 13b1 and the second segment 13b2. The detection information from the sensor 19 is input to the controller 68 that controls the drive device 65. Based on the detection information from the sensor 19, the controller 68 calculates the steering torque and speed of the steering wheel operation and controls the output of the drive device 65. The torque of the drive device 65 controlled by the controller 68 is used to assist the driver in steering the steering wheel 2.

[0078] The first bevel gear 14 is supported on the middle part of the third shaft 13c in a manner coaxial with and capable of rotating integrally with the third shaft 13c. A second bevel gear 15 meshes with the first bevel gear 14. The second bevel gear 15 is supported on the top end of the first output shaft 16 in a manner coaxial with and capable of rotating integrally with the first output shaft 16.

[0079] The first output gear 17 is supported on the first output shaft 16 in a manner that is coaxial with and capable of rotating integrally with the first output shaft 16. The first output gear 17 meshes with the operating side transmission gear 56a of the second gear mechanism 20.

[0080] The first gear mechanism 11 is configured such that the first output shaft 16 is orthogonal to the operation input shaft 13, thus forming an orthogonal input-output mechanism. For example, when the driver operates the operation input shaft 13 to rotate it, the first gear mechanism 11 transmits the rotational force of the operation input shaft 13 to the first bevel gear 14. The rotational force of the first bevel gear 14 is then transmitted to the transmission gear 56 via the second bevel gear 15, the first output shaft 16, and the first output gear 17.

[0081] The first bevel gear 14, supported on the third shaft portion 13c, abuts against the inner ring of the bearing 12d via a shim 14s. Furthermore, the bearing 12d is positioned adjacent to the first bevel gear 14 on the other side (-f1) of the first axial direction F1. A pair of bearings 12d are supported on the inner circumference of the second plug body 12c with their movement restricted in the first axial direction F1. The bearings 12d receive the thrust load of the first bevel gear 14 via the shim 14s. Therefore, by adjusting the thickness of the shim 14s, the backlash between the first bevel gear 14 and the second bevel gear 15 can be reduced.

[0082] <Second Gear Mechanism 20>

[0083] like FIG. 7 , FIG. 8 As shown, the second gear mechanism 20 is configured, for example, as an eccentric oscillating transmission.

[0084] The second gear mechanism 20 includes a gear housing 21, a gear section 40, and three crankshaft assemblies 50. The gear housing 21 houses the gear section 40 and the three crankshaft assemblies 50. In this embodiment, the mechanism components including the gear section 40 and the three crankshaft assemblies 50 are collectively referred to as the reduction mechanism component 20d.

[0085] The gear housing 21 includes a first housing (gear carrier housing) 22 and a second housing (outer cylinder housing) 23. The first housing 22 has a fixing part that is fixed to the vehicle body. The second housing 23 is formed into a cylindrical shape centered on the central axis (second axis) C2 of the output shaft 25, and is arranged in a manner that allows it to rotate relative to the first housing 22. The second housing 23 is supported on the outer periphery of the first housing 22 by means of a pair of main bearings 24 that are axially separated. The second housing 23 is an example of an output member of the second gear mechanism 20. When the first housing 22 is fixed to a support such as the vehicle body, the second housing 23 becomes an output member.

[0086] The first housing 22 includes a base 27, an end plate 28, a locating pin 29, and a fixing bolt 31. The first housing 22 is generally formed into a cylindrical shape coaxial with the output shaft 25. The first housing 22 functions as a gear carrier supporting the three crankshaft assemblies 50.

[0087] The base portion 27 includes a base plate portion 32 and three shaft portions 33. The three shaft portions 33 extend from the base plate portion 32 toward the other side (-f2) in the second axial direction F2. The end plate portion 28 is mounted relative to the base portion 27 on the side opposite to the base plate portion 32 in the axial direction. The three shaft portions 33 pass through the gear portion 40 and are connected to the end plate portion 28.

[0088] Threaded holes 35 and reamed holes 36 are formed on the top surfaces of the three shaft portions 33. Locating pins 29 are inserted into the reamed holes 36. As a result, the end plate portion 28 is positioned with high precision relative to the base portion 27. Fixing bolts 31 are screwed into the threaded holes 35. As a result, the end plate portion 28 is fixed to the base portion 27.

[0089] A flange 37 is mounted on one side (+f2) of the base plate portion 32 constituting the first housing 22 along the second axial direction F2. An oil chamber R1 is formed between the flange 37 and the circular plate portion 25a provided on the base end side of the output shaft 25 to house the reduction mechanism component 20d of the second gear mechanism 20. A predetermined amount of gear oil is stored in the oil chamber R1 to lubricate the reduction mechanism component 20d.

[0090] The end of the second housing 23 located on the other side (-f2) of the second axial direction F2 is fixed to the outer periphery of the circular plate portion 25a by a plurality of bolts B1 arranged circumferentially. The flange portion 37 has a bottomed cylindrical recess 37a1. The end of the second housing 23 located on the side (+f2) of the second axial direction F2 enters the opening of the recess 37a1.

[0091] An oil seal 23c is fitted between the outer periphery of the end of the second housing 23 located on the second axial direction F2 (+f2) and the inner periphery of the opening of the recess 37a1 of the flange portion 37. An oil seal 45c is fitted between the outer periphery of the second input shaft 45 and the inner periphery of the shaft through hole of the flange portion 37.

[0092] The oil chamber R1 communicates with the internal space K1 of the protrusion 12e of the housing portion 12 of the first gear mechanism 11 via the space of the meshing portion where the transmission gear 56 meshes with the first output gear 17 of the first gear mechanism 11. Therefore, the internal space K1 of the protrusion 12e is a communicating space that communicates with the oil chamber R1. In contrast, the cylindrical internal space of the housing portion 12 that houses the bevel gear is a separate space K2 that is oil-tightly separated from the internal space K1 by an oil seal 16c.

[0093] Here, the rotational speed of each gear in the first gear mechanism 11 is lower than that of the second gear mechanism 20. Therefore, instead of designating an oil chamber R1 as the storage part for each gear, each gear is coated with grease or the like. As a result, the amount of oil filled into the steering unit 10 can be reduced, achieving weight reduction, cost reduction, and reduced friction caused by oil churning in low-temperature environments.

[0094] Furthermore, when an oil chamber R1 is formed in the first gear mechanism 11, a dedicated oil seal is sometimes required around the sensor to prevent oil from adhering to the sensor located in the first gear mechanism 11. In contrast, in this embodiment, the first gear mechanism 11 is designed without an oil chamber R1, so a conventional oil seal 16c can be provided between the first gear mechanism 11 and the second gear mechanism 20. Therefore, cost reduction can also be achieved in this respect.

[0095] Multiple fastening protrusions 37b are provided on the outer side of the flange portion 37 as fixing parts for fixing to the vehicle body. Each fastening protrusion 37b is formed, for example, in a cylindrical shape along the second axial direction F2.

[0096] The second housing 23 has a plurality of internal toothed pins (internal teeth) 26 on its inner circumferential surface. Each internal toothed pin 26 is a cylindrical member extending parallel to the second axis C2. Each internal toothed pin 26 is embedded in a pin groove formed in the inner wall of the second housing 23. Each internal toothed pin 26 is properly held by the second housing 23.

[0097] Multiple internal toothed pins 26 are arranged at equal intervals in the circumferential direction around the second axis C2. The semi-circular surface of each internal toothed pin 26 protrudes from the inner wall of the second housing 23 toward the inner circumferential side. The multiple internal toothed pins 26 function as internal teeth that mesh with the external teeth of the gear section 40.

[0098] A gear section 40 is disposed between a base plate section 32 and an end plate section 28. The gear section 40 includes two oscillating gears (external gear members) 41 and 42. The oscillating gear 41 is disposed between the base plate section 32 and the oscillating gear 42, and has external teeth that mesh with a plurality of internal tooth pins 26. The oscillating gear 42 is disposed between the end plate section 28 and the oscillating gear 41, and has external teeth that mesh with a plurality of internal tooth pins 26. The external teeth of each oscillating gear 41 and 42 are formed into a smooth, continuous wave shape throughout the entire circumference of each oscillating gear 41 and 42.

[0099] The two oscillating gears 41 and 42 are of the same shape and size. While engaging with the internal toothed pin 26 of the second housing 23, the two oscillating gears 41 and 42 move around within the second housing 23. At this time, the centers of the two oscillating gears 41 and 42 revolve around the second axis C2. This movement of each oscillating gear 41 and 42 is defined as "oscillating rotation".

[0100] When each oscillating gear 41, 42 oscillates and rotates, the center of each oscillating gear 41, 42 revolves around the second axis C2 once. Each time each oscillating gear 41, 42 revolves once, a relative rotation occurs between each oscillating gear 41, 42 and the second housing 23 at an angle equivalent to the difference in the number of teeth between the external teeth of each oscillating gear 41, 42 and the internal teeth (internal tooth pin 26) of the second housing 23.

[0101] The two oscillating gears 41 and 42 are staggered by 180° in their circumferential phase. When one oscillating gear 41 engages with half of the internal toothed pins 26, the other oscillating gear 42 engages with the remaining half of the internal toothed pins 26. Therefore, the gear section 40 generates relative rotational torque between the first housing 22 and the second housing 23 at the two points where each oscillating gear 41, 42 engages with the second housing 23.

[0102] Each of the three crankshaft assemblies 50 includes a crankshaft 51, four bearings 52, 53, 54, and 55, and a transmission gear 56.

[0103] Three crankshaft assemblies 50 are arranged at equal intervals around the second axis C2. Line C2a in the figure represents the rotational center axis (crankshaft axis) of each crankshaft 51. Each crankshaft axis C2a is parallel to the second axis F2 and parallel to the second axis C2. Each crankshaft 51 rotates about the crankshaft axis C2a.

[0104] Each crankshaft 51 includes two journals (crankshaft journals) 58 and 59 and two eccentric portions (eccentric bodies) 61 and 62. The two journals 58 and 59 are each formed into a cylindrical shape centered on the crankshaft axis C2a. The journal 58 located on one side (+f2) of the second axis F2 is supported on the base 27 by means of a first bearing 52. The journal 59 located on the other side (-f2) of the second axis F2 is supported on the end plate portion 28 by means of a second bearing 53.

[0105] In each crankshaft 51, two eccentric portions 61 and 62 are formed between two journals 58 and 59. The two eccentric portions 61 and 62 have a central axis that is eccentric relative to the corresponding crankshaft axis C2a. The two eccentric portions 61 and 62 are formed in a cylindrical shape that is eccentric relative to the two journals 58 and 59.

[0106] An eccentric portion 61 located on one side (+f2) of the second axis F2 is inserted into a third bearing 54. The eccentric portion 61 and the third bearing 54 pass through the crankshaft through-hole of the oscillating gear 41 located on one side (+f2) of the second axis F2. The oscillating gear 41 located on one side (+f2) of the second axis F2 undergoes eccentric movement according to the rotation of the eccentric portion 61 located on one side (+f2) of the second axis F2.

[0107] An eccentric portion 62 located on the other side (-f2) of the second axis F2 is inserted into a fourth bearing 55. The eccentric portion 62 and the fourth bearing 55 pass through the crankshaft through-hole of the oscillating gear 42 located on the other side (-f2) of the second axis F2. The oscillating gear 42 located on the other side (-f2) of the second axis F2 undergoes eccentric movement according to the rotation of the eccentric portion 62 located on the other side (-f2) of the second axis F2.

[0108] Each transmission gear 56 meshes with a second input gear 46 coaxial with the second input shaft 45. The second input gear 46 is integrally formed, for example, on the outer periphery of the second input shaft 45. The second input shaft 45 is coaxial with and integrally formed with the output shaft (transmission output shaft 76b) of the transmission mechanism 70. The second input gear 46 is also integrally formed with the transmission output gear 76c on the transmission output shaft 76b (see reference). FIG. 7 ).

[0109] The driven pulley support shaft 76a, which is connected to the portion of the transmission output shaft 76b located on one side (+f2) of the second axial direction F2, is rotatably supported by bearing 37d on the shaft support portion 37c of the flange portion 37 that closes one side (+f2) of the gear housing 21 on the second axial direction F2.

[0110] The shaft portion 47, which is connected to the portion of the second input shaft 45 located on the other side (-f2) of the second axial direction F2, extends into the second gear mechanism 20 over the transmission gear 56 in the second axial direction F2. Furthermore, the shaft portion 47 is supported by the shaft support portion 21c of the gear housing 21 (e.g., base plate portion 32) of the second gear mechanism 20 by means of the bearing 21d.

[0111] Three transmission gears 56, located on each crankshaft 51, are arranged at equal intervals around the second input gear 46 in the circumferential direction and mesh with the second input gear 46 respectively. Furthermore, when viewed from the second axial direction F2, the three transmission gears 56 are arranged such that the imaginary line connecting their centers forms a triangle (see reference). FIG. 7 ).

[0112] The diameter of the second input gear 46 is smaller than the diameter of each transmission gear 56. Each transmission gear 56 reduces the rotational speed input from the second input gear 46. When viewed from the second axis F2, the three transmission gears 56 are positioned inside the circular outer shape A2 of the second gear mechanism 20. The output of the drive unit 65, which has been reduced in speed by the transmission mechanism 70, is transmitted to the second input gear 46.

[0113] The central axis (crankshaft axis C2a) of the transmission gear 56 located on the side of the first gear mechanism 11 (hereinafter referred to as the operating side transmission gear) 56a is arranged in the... FIG. 5 The imaginary plane S1, shown by the straight line in the middle, is a plane along the second axis F2 and the third axis F3, and is orthogonal to the first axis F1. The first output gear 17 of the first gear mechanism 11 meshes with the operating side transmission gear 56a. The first output gear 17 is formed with a diameter larger than that of the operating side transmission gear 56a. The operating side transmission gear 56a increases the speed of the rotation input from the first output gear 17.

[0114] The driving force generated by the drive unit 65 is input to each transmission gear 56 via the transmission mechanism 70. By using one of the three transmission gears 56 (operation-side transmission gear 56a) as the input gear that receives the rotation of both the first gear mechanism 11 and the drive unit 65, it is possible to reduce the number of parts and achieve miniaturization compared to the case where input gears are provided respectively corresponding to the first gear mechanism 11 and the drive unit 65.

[0115] When the driving force of the drive unit 65 is input to each transmission gear 56, each crankshaft 51 rotates about the crankshaft axis C2a. As a result, the two eccentric portions 61 and 62 of each crankshaft 51 rotate eccentrically about the corresponding crankshaft axis C2a. When viewed from the second axis F2, the first output gear 17 passes over the outer shape A2 of the second gear mechanism 20 and meshes with the operating side transmission gear 56a.

[0116] Two oscillating gears 41 and 42, connected to the eccentric portions 61 and 62, oscillate and rotate within a circular space defined by the second housing 23. The two oscillating gears 41 and 42 mesh with the internal toothed pins 26 of the second housing 23. Therefore, by oscillating and rotating the two oscillating gears 41 and 42, relative rotational motion is generated between the first housing 22 and the second housing 23. Furthermore, by utilizing the eccentric rotation of each crankshaft 51 to oscillate and rotate each oscillating gear 41 and 42, an output rotation that decelerates relative to the input rotation can be obtained.

[0117] In the steering unit 10 of this embodiment configured as described above, when the steering wheel 2 is rotated, the steering wheel operating force is transmitted via the first gear mechanism 11 to one of the three transmission gears 56 (operation-side transmission gear 56a). During this power transmission process, since the diameter of the first output gear 17 of the first gear mechanism 11 is larger than the diameter of the transmission gear 56, the steering wheel operating force is increased. The steering wheel operating force input to one of the three transmission gears 56 (operation-side transmission gear 56a) is also transmitted to the other two transmission gears 56 via the second input gear 46.

[0118] At this time, sensor 19 within the first gear mechanism 11 detects the torsion of the operating input shaft 13. Controller 68, based on the detection information from sensor 19, drives drive device 65. The driving force of drive device 65 is then reduced by transmission mechanism 70 and transmitted to the second input shaft 45, and subsequently from the second input gear 46 to the three transmission gears 56. Therefore, during the power transmission from the second input gear 46 to each transmission gear 56, the driving force of drive device 65 is reduced.

[0119] The second gear mechanism 20 utilizes the combined force of the steering wheel operating force and the motor driving force input to each transmission gear 56 to cause the first eccentric portion 61 and the second eccentric portion 62 of each crankshaft 51 to rotate eccentrically. As a result, the first oscillating gear 41 and the second oscillating gear 42 oscillate and rotate with a predetermined phase difference. When the drive device 65 and each drive circuit 68b, 68c fail, and the auxiliary torque generated by the drive device 65 becomes 0 or reduced, the steering wheel operating force is used to rotate each crankshaft 51, causing the first oscillating gear 41 and the second oscillating gear 42 to oscillate and rotate.

[0120] While the first oscillating gear 41 and the second oscillating gear 42 oscillate and rotate within the second housing 23, the first and second external teeth pass over the internal tooth pin 26. This generates a relative rotation between the first housing 22, which supports the first oscillating gear 41 and the second oscillating gear 42, and the second housing 23, which holds the internal tooth pin 26, resulting in a significant reduction in input rotational speed. Thus, by fixing one of the first housing 22 and the second housing 23 to a support such as a vehicle body and using the other as an output member, an eccentric oscillating gear device that significantly reduces input rotational speed and outputs it is constructed.

[0121] <Transmission Mechanism 70>

[0122] like FIG. 2 , FIG. 3 As shown, the transmission mechanism 70 is located in the unit housing 10c on one side (+f2) along the second axis F2. The transmission mechanism 70 transmits power from the drive unit 65 to the second input shaft 45 of the second gear mechanism 20. When viewed axially from the second axis F2, the transmission mechanism 70 is located across the drive unit 65 and the second gear mechanism 20.

[0123] The transmission mechanism 70 includes a transmission housing 71, a drive pulley 75, a driven pulley 76, a transmission belt 77, and a tensioner 78. In this embodiment, the mechanism components including the drive pulley 75, the driven pulley 76, the transmission belt 77, and the tensioner 78 are collectively referred to as transmission mechanism components 70d.

[0124] The transmission housing 71 includes a housing body 72 and a housing cover 73.

[0125] The housing body 72 is secured to the portion of the flange 37 located on one side (+f2) along the second axial direction F2 using multiple bolts B3. The housing cover 73 closes the open portion of the housing body 72 located on one side (+f2) along the second axial direction F2. Furthermore, in... FIG. 2 The illustration of the housing cover 73 is omitted in the text.

[0126] A cover 72a is integrally formed on one side (+f3) of the housing body 72 in the third direction F3. When viewed from the second axis F2, the cover 72a extends from the receiving portion of the driven pulley 76 to a position overlapping with the first gear mechanism 11 (avoiding the position of the second gear mechanism 20). The cover 72a closes the opening of the protrusion 12e of the housing portion 12 of the first gear mechanism 11 from one side (+f2) in the second axis F2.

[0127] The outer periphery of the cover portion 72a, when viewed from the second axial direction F2, has a plurality of fastening portions 72b that are fastened to the housing portion 12. The inner periphery of the cover portion 72a, when viewed from the axial direction, has a bulge portion 72c that bulges out to the side (+f2) of the fastening portions 72b facing the second axial direction F2.

[0128] The bulge 72c covers the top end of the first output shaft 16 of the first gear mechanism 11 from one side (+f2) in the second axial direction F2. The bulge 72c is formed in the second axial direction F2 within the width H4 (excluding the local protrusion) of the main part of the transmission housing 71, thus suppressing the enlargement in the second axial direction F2. The width H4 is, for example, set to be the width from the side 37a2 of the flange portion 37 located on one side (+f2) in the second axial direction F2 to the top end of one side (+f2) in the second axial direction F2 of the transmission housing 71.

[0129] An internal space K1 is formed on the inner side of the bulge 72c, communicating with the oil chamber R1 inside the gear housing 21 of the second gear mechanism 20. When viewed from the second axial direction F2, the internal space K1 is formed at a position further outward than the outer shape A2 of the second gear mechanism 20. By setting the internal space K1, it is easy to ensure the ratio of the space (the remaining space not filled with oil) to the overall volume of the oil chamber.

[0130] On the other hand, within the transmission housing 71, the internal space housing the transmission mechanism component 70d becomes a second separation space K3, which is oil-tightly separated from the oil chamber R1 of the second gear mechanism 20 by the oil seal 45c. By making the transmission mechanism 70 oil-free, reliable power transmission can be achieved using the transmission belt 77, and the oil seal on the drive unit 65 side is not required.

[0131] The drive pulley 75 is coaxially configured with the drive shaft 67 of the drive unit 65 and is mounted on the drive pulley support shaft 75a in a manner that allows it to rotate integrally with the drive pulley support shaft 75a, which is provided in a manner that extends the drive shaft 67.

[0132] The driven pulley 76 is coaxially configured with the second input shaft 45 of the second gear mechanism 20, and is mounted on the driven pulley support shaft 76a in such a way that it can rotate integrally with the driven pulley support shaft 76a, which is provided in a manner that extends the second input shaft 45.

[0133] The driven pulley 76 is formed with a diameter larger than that of the drive pulley 75, thereby reducing the rotational speed input from the drive pulley 75. The transmission mechanism 70 reduces the output of the drive unit 65 and transmits it to the second gear mechanism 20. Furthermore, although simplified in the various figures, the transmission belt 77 is, for example, a toothed belt. Thus, reliable torque transmission can be achieved using the transmission belt 77.

[0134] Within the transmission housing 71, a second separation space K3, separated from the oil chamber R1 within the second gear mechanism 20, is formed by an oil seal 45c located on the outer periphery of the second input shaft 45 and an O-ring 37c1 located on the outer periphery of the shaft support portion 37c of the flange portion 37. In this embodiment, the oil seal 45c and the O-ring 37c1 are collectively referred to as the second oil seal. The second separation space K3 is oil-free, suppressing slippage of the transmission belt 77. The drive shaft 67 of the drive device 65 is located in the second separation space K3. However, even if an oil seal is not provided on the outer periphery of the drive shaft 67, oil will not intrude into the drive device 65.

[0135] <Shell / Flange Molded Parts 38>

[0136] FIG. 9 This is a perspective view showing the housing flange molded article 38 formed by integrating the flange portion 37 and the housing portion 12 of the forming unit housing 10c, and the gasket plate 39 mounted on the housing flange molded article 38.

[0137] like FIG. 9 As shown, the flange portion 37 includes the housing portion 12 of the first gear mechanism 11, and is integrally formed with the housing portion 12 using the same material as the housing portion 12. The flange portion 37 and the housing portion 12 are integrally formed by casting or the like (housing and flange member 38). The aluminum alloy flange portion 37 has a shallow recess 37a1 with a bottomed cylindrical shape. Furthermore, the flange portion 37 includes a base plate portion 37a that closes one end side of the housing of the second gear mechanism 20 in the axial direction and a plurality of fastening protrusions 37b extending to the outer periphery of the base plate portion 37a.

[0138] The housing portion 12 is located on one side (+f3) of the substrate portion 37a in the third direction F3, and is configured to be displaced from the substrate portion 37a on the other side (-f2) in the second axis F2. A protrusion 12e formed in the portion of the housing portion 12 located on the side (+f2) in the second axis F2 is provided in a manner connected to the side (+f3) of the flange portion 37 in the substrate portion 37a in the third direction F3. The protrusion 12e and the substrate portion 37a form a continuous opening peripheral portion along a plane (side surface) orthogonal to the second axis F2.

[0139] A plurality of fastening bolts B2 are mounted on the base plate portion 37a to secure the first housing 22 (gear carrier) of the gear housing 21 of the second gear mechanism 20. When viewed from the second axis F2, a predetermined number (seven) of the plurality of fastening bolts B2 are arranged in three regions that avoid the three transmission gears 56. Corresponding to these predetermined number of fastening bolts B2, a washer plate 39 is provided in a fan shape when viewed from the second axis F2.

[0140] Each washer plate 39 is made of an iron-based material including steel, and is formed to have a higher hardness than the housing / flange member 38. Each washer plate 39 has multiple through holes for a predetermined number of fastening bolts B2 to pass through. Each washer plate 39 is formed as a large plate that includes not only the bolt seat surface of each fastening bolt B2, but also the area between adjacent fastening bolts B2 and the area outside the bolt penetration range, and contacts one side of the base plate portion 37a.

[0141] As a result, the surface pressure applied to the housing / flange member 38 due to bolt tightening is reduced by the washer plate 39. Therefore, even when the fastening bolt B2 is tightened with a specified tightening torque, deformation of the housing / flange member 38 made of light alloys such as aluminum alloy can be suppressed. Thus, the first housing 22 of the second gear mechanism 20 can be reliably fixed to the housing / flange member 38.

[0142] <Reversing configuration of the first gear mechanism 11>

[0143] FIG. 10A This is a perspective view showing the state in which the conversion mechanism component 11d of the first gear mechanism 11 is separated from the housing portion 12. FIG. 10B This indicates that the housing flange member 38 is relative to... FIG. 10A A three-dimensional view of the state in which it is flipped over along the first axis F1.

[0144] like FIG. 10A , FIG. 10B As shown, the conversion mechanism component 11d of the first gear mechanism 11 can be separated in the axial direction (first axial direction F1) of the operation input shaft 13.

[0145] In the first gear mechanism 11, the socket portion 13bs of the second shaft portion 13b is configured to be insertable and detachable relative to the third shaft portion 13c by relative movement along the first axial direction F1. A mechanism component located on one side (+f1) of the socket portion 13bs along the first axial direction F1 forms a first assembly including a first plug body 12a and a sensor 19. The first assembly can be attached to and detached relative to the housing portion 12 along the first axial direction F1 from one side (+f1). A mechanism component located on the other side (-f1) of the socket portion 13bs along the first axial direction F1 forms a second assembly including a second plug body 12c and a first bevel gear 14. The second assembly can be attached to and detached relative to the housing portion 12 along the first axial direction F1 from the other side (-f1).

[0146] In the housing portion 12, the openings on both sides along the first axial direction F1 are symmetrically arranged along the first axial direction F1. The central axis (orthogonal axis C1a) of the second bevel gear 15 and the first output shaft 16 is located in the central portion of the housing portion 12 along the first axial direction F1. The central axis C1a of the second bevel gear 15 is configured to intersect the central axis (first axis C1) of the first bevel gear 14. Regardless of which side of the first axial direction F1 the second assembly is installed in the housing portion 12, the second bevel gear 15 can mesh with the first bevel gear 14. Furthermore, if the second assembly is installed from either side of the first axial direction F1 of the housing portion 12, by installing the first assembly from the opposite side of the first axial direction F1 of the housing portion 12, the socket portion 13bs of the second shaft portion 13b can be connected to the third shaft portion 13c.

[0147] Therefore, the first gear mechanism 11 can be configured in a specified manner (e.g., referring to...) FIG. 10A ) and a flip configuration that flips the first axis F1 relative to the specified configuration (e.g., refer to FIG. 10B Any of the configurations in ) is installed in the housing 12.

[0148] The housing flange member 38 has an imaginary plane S1 along the second axial direction F2 and the third axial direction F3 (see reference). FIG. 5 Formed symmetrically. FIG. 10A , FIG. 10B In this text, the arrangement of the housing and flange member 38 is shown not with the first gear mechanism 11 reversed, but with the housing and flange member 38 reversed. FIG. 10A , FIG. 10B As shown, by flipping the configuration of the housing and flange member 38 (the configuration of the steering unit 10) and mounting it on the vehicle, the steering unit 10 can be mounted on either right-hand drive or left-hand drive vehicles.

[0149] Typically, in the steering unit 10, the layout of the input and output sections needs to be changed to accommodate the differences between right-hand and left-hand drive. Therefore, for the steering unit 10, sometimes dedicated frames are prepared for both right-hand and left-hand drive applications.

[0150] In contrast, the steering unit 10 of this embodiment can realize the flipping configuration of the first gear mechanism 11, and the housing / flange member 38 is formed symmetrically about an imaginary plane S1 (orthogonal to the first axis F1) along the second axis F2 and the third axis F3. Thus, as FIG. 10A , FIG. 10B As shown, the configuration of the steering unit 10 can be flipped and mounted on the vehicle. Therefore, if the housing and flange member 38 and the first gear mechanism 11 are recombined according to right-hand drive and left-hand drive respectively, the layout of the input and output section that can accommodate the differences between right-hand drive and left-hand drive can be realized while using common components.

[0151] As described above, the steering unit 10 in this embodiment includes: a first gear mechanism 11, which is input with a rotation operated by a steering wheel, changes the direction of the rotation, and outputs a single rotation; and a second gear mechanism 20, which is input with a single rotation output from the first gear mechanism 11, reduces the speed of the single rotation, and outputs it. The first gear mechanism 11 is configured to be at least partially within the width H2 of the second gear mechanism 20 along the axial direction (second axial direction F2) of the output shaft (second output shaft 25) of the second gear mechanism 20.

[0152] According to this structure, a first gear mechanism 11 (operating mechanism) that converts the rotation direction of the steering wheel operation and a second gear mechanism (reducer) 20 that reduces the output of the first gear mechanism 11 can be arranged overlapping each other on the second axis F2 of the second gear mechanism 20. Therefore, the thickness of the entire device on the second axis F2 can be reduced, thereby achieving miniaturization.

[0153] Furthermore, the steering unit 10 includes a drive device 65 that outputs a driving force to assist steering wheel operation. The drive device 65 is configured to be at least partially within the width H2 of the second gear mechanism 20 along the second axial direction F2.

[0154] According to this structure, the drive unit 65 (auxiliary motor) that outputs steering assist force can also be arranged to overlap each other on the second axis F2 of the second gear mechanism 20. Therefore, it is possible to further reduce the thickness of the entire device, including the drive unit 65, on the second axis F2, thereby achieving miniaturization.

[0155] Furthermore, in the steering unit 10, the second gear mechanism 20 has a primary input gear (operating-side transmission gear 56a) positioned more inward than the outer shape A2 when viewed from the second axial direction F2. The first gear mechanism 11 has a first output gear 17 formed with a diameter larger than that of the operating-side transmission gear 56a. The first output gear 17 meshes with the operating-side transmission gear 56a.

[0156] According to this structure, for the second gear mechanism 20, the operating side transmission gear 56a is arranged inside the outer shape A2 of the second gear mechanism 20 when viewed from the second axial direction F2, thereby achieving miniaturization of the second gear mechanism 20. The first output gear 17 of the first gear mechanism 11 is formed with a diameter larger than that of the operating side transmission gear 56a and meshes with the operating side transmission gear 56a. Thus, the first output gear 17 can realize the power transmission between the two gear mechanisms 11 and 20 while ensuring the spacing between the first gear mechanism 11 and the second gear mechanism 20, and increase the rotational output of the first gear mechanism 11 and transmit it to the second gear mechanism 20.

[0157] Furthermore, the steering unit 10 includes a transmission mechanism 70 that connects the drive unit 65 to the second gear mechanism 20. The transmission mechanism 70 reduces the driving force of the drive unit 65 and transmits it to the second gear mechanism 20.

[0158] According to this structure, by slowing down the driving force (output) of the drive device 65 and transmitting it to the second gear mechanism 20, the torque generated by the drive device 65 can be suppressed, thereby achieving miniaturization of the drive device 65.

[0159] Furthermore, in the steering unit 10, the second gear mechanism 20 includes a transmission gear 56 comprising an operating side transmission gear 56a and a second input gear 46 having a diameter smaller than that of the transmission gear 56. The second input gear 46 meshes with the transmission gear 56. The transmission mechanism 70 transmits the driving force of the drive device 65 to the second input gear 46.

[0160] According to this structure, by transmitting the driving force of the drive device 65 to the second input gear 46 of the second gear mechanism 20, the driving force of the drive device 65 can be further reduced, and the output torque of the drive device 65 can be suppressed to achieve miniaturization.

[0161] Furthermore, in the steering unit 10, the drive unit 65 has a drive shaft 67 arranged parallel to the second output shaft 25 of the second gear mechanism 20. When viewed from the second axis F2, the drive unit 65 has an outer shape A3 that is smaller than the outer shape A2 of the second gear mechanism 20.

[0162] According to this structure, the drive unit 65 and the second gear mechanism 20 can be arranged side-by-side with their axial directions parallel to each other. Therefore, compared to the case where the drive unit 65 and the second gear mechanism 20 are arranged to overlap each other in the axial direction, the overall device can be miniaturized along the second axial direction F2. Furthermore, by making the drive unit 65 smaller than the second gear mechanism 20 when viewed from the second axial direction F2, the overall device can be miniaturized when viewed from the axial direction.

[0163] Additionally, in the steering unit 10, the second gear mechanism 20 has an input shaft (second input shaft 45) that is input to rotate once. The transmission mechanism 70 includes: a drive pulley 75 mounted on the drive shaft 67 of the drive device 65, which has a relatively small diameter; a driven pulley 76 mounted on the input shaft (second input shaft 45) of the second gear mechanism 20, which is formed to have a diameter relatively larger than that of the drive pulley 75; and a transmission belt 77 wound around the two pulleys 75 and 76.

[0164] According to this structure, the drive unit 65 and the second gear mechanism 20 can be connected via a belt-type transmission mechanism 70. Therefore, compared with the case of using a gear-type transmission mechanism, the influence of backlash can be suppressed, thereby improving working accuracy. Moreover, the spacing between the drive unit 65 and the second gear mechanism 20 can be ensured with fewer parts.

[0165] Furthermore, the steering unit 10 includes a driven pulley support shaft 76a that supports the driven pulley 76. The driven pulley support shaft 76a also serves as a transmission output shaft 76b that transmits driving force to the second gear mechanism 20.

[0166] According to this structure, by sharing (or using) the driven pulley support shaft 76a and the transmission output shaft 76b, the number of parts can be reduced, thereby achieving weight reduction and improved working accuracy.

[0167] Additionally, in the steering unit 10, the second gear mechanism 20 includes a second input gear 46 (transmission output gear 76c). The second input gear 46 is integrally formed on the transmission output shaft 76b.

[0168] According to this structure, by integrating the second input gear 46 of the second gear mechanism 20 with the transmission output shaft 76b, which also serves as the driven pulley support shaft 76a, the number of parts can be reduced, thereby achieving weight reduction and improved working accuracy.

[0169] Furthermore, in the steering unit 10, the transmission output shaft 76b has a shaft portion 47 that extends along the second axis F2 past the second input gear 46 and into the second gear mechanism 20. The shaft portion 47 is supported inside the second gear mechanism 20 by means of a bearing 21d.

[0170] According to this structure, by having a shaft portion 47 supported within the second gear mechanism 20 at the top end of the transmission output shaft 76b, the transmission output shaft 76b can be supported by both bearings 37d on the transmission mechanism 70 side and bearing 21d on the second gear mechanism 20 side. Therefore, compared to using only the bearings on the transmission mechanism 70 side to support the transmission output shaft 76b, the bearing structure on the transmission mechanism 70 side can be simplified and miniaturized.

[0171] Furthermore, the steering unit 10 includes: a flange portion 37, which forms a side portion of the gear housing 21 of the second gear mechanism 20 facing the second axial direction F2; and a housing portion 12, which houses the conversion mechanism component 11d of the first gear mechanism 11. The flange portion 37 and the housing portion 12 are integrally formed together.

[0172] According to this structure, the flange portion 37 of the gear housing 21 forming the second gear mechanism 20, which faces the side (+f2) on the second axial direction F2, is integrally formed with the housing portion 12 of the first gear mechanism 11. Therefore, the number of parts can be reduced to achieve weight reduction, and the accuracy of the relative position between the first gear mechanism 11 and the second gear mechanism 20 can be improved, thereby improving working accuracy.

[0173] Furthermore, the steering unit 10 includes: a plurality of fasteners B2 that fix the housing body (first housing 22) of the gear housing 21 of the second gear mechanism 20 to the flange portion 37; and a washer plate 39 disposed between the flange portion 37 and the plurality of fasteners B2, and fixed between the seat surfaces of the plurality of fasteners B2 and the flange portion 37 by screwing in the plurality of fasteners B2. The washer plate 39 is formed to a size that allows contact between the seat surfaces of at least two of the plurality of fasteners B2.

[0174] According to this structure, the washer plate 39 used to fasten the first housing 22 of the second gear mechanism 20 to the flange portion 37 can be formed to span the seat surface of multiple fasteners B2. Therefore, compared to the case where individual washers are provided for each fastener B2, the area in the washer plate 39 located between each fastener B2 contacts the flange portion 37. Consequently, the surface pressure applied to the flange portion 37 due to the screwing in of each fastener B2 is reduced. As a result, even when the flange portion 37 is formed of a light metal with low hardness, deformation of the seat surface side of the flange portion 37 can be suppressed and the screwing torque of each fastener B2 can be ensured, thus improving reliability.

[0175] Furthermore, in the steering unit 10, a controller 68 is provided at one end of the drive device 65. The controller 68 is configured to overlap with the drive device 65 in the axial direction (drive axis, second axis F2) of the drive shaft 67, and controls the drive of the drive device 65. When viewed from the axial direction of the drive shaft 67, the controller 68 is formed as a flat shape with an outer diameter larger than that of the drive device 65, thereby suppressing the thickness of the drive device 65 along the axial direction of the drive shaft 67.

[0176] According to this structure, the controller 68, which is disposed at the end of the drive unit 65 in an axially overlapping manner with the drive shaft, is formed into a flat shape with an outer diameter larger than that of the drive unit 65 when viewed from the drive axis. Therefore, it is possible to ensure the size of the controller 68 while suppressing the thickness of the axial dimension of the drive unit 65, including the controller 68, thereby improving reliability.

[0177] Furthermore, in the steering unit 10, the first gear mechanism 11 includes a first input shaft 13 that is rotated by the input steering wheel. The axial direction of the first input shaft 13 is defined as the first axial direction F1. The first gear mechanism 11 is configured such that the first axial direction F1 intersects the second axial direction F2 of the second gear mechanism 20. The first gear mechanism 11 and the second gear mechanism 20 are configured to be arranged along a third direction (intersection direction) F3 that intersects the first axial direction F1 and the second axial direction F2. The flange portion 37 and the housing portion 12 are formed symmetrically with respect to an imaginary plane S1 along the second axial direction F2 and the third direction F3. The first gear mechanism 11 can be mounted in a posture in which the conversion mechanism member 11d is flipped relative to the orientation of the housing portion 12 along the first axial direction F1.

[0178] According to this structure, the flange portion 37 and the housing portion 12 are formed symmetrically with respect to an imaginary plane S1 (a plane orthogonal to the first axis F1) along the second axis F2 and the third axis F3. Furthermore, the conversion mechanism component 11d of the first gear mechanism 11 can be mounted relative to the housing portion 12 in a manner that reverses its orientation along the first axis F1. Therefore, the steering unit 10 can be shared in both right-hand and left-hand drive configurations.

[0179] That is, when the steering unit 10 is mounted on both right-hand drive and left-hand drive vehicles, the larger components such as the second gear mechanism 20 in the steering unit 10 are arranged approximately symmetrically in both right-hand drive and left-hand drive configurations. Therefore, by allowing the first axis F1 (pointing vertically when mounted on a vehicle) of the first gear mechanism 11 connected to the steering shaft 3 to be rotated, and by making the flange portion 37 of the second gear mechanism 20 and the housing portion 12 symmetrical with respect to an imaginary plane S1 orthogonal to the first axis F1, a symmetrical steering unit 10 can be obtained and mounted on both right-hand drive and left-hand drive vehicles. Therefore, the versatility of the steering unit 10 can be improved, thereby reducing costs.

[0180] Furthermore, in the steering unit 10, the gear housing 21 that houses the reduction mechanism component 20d in the second gear mechanism 20 forms an oil chamber R1 that houses the reduction mechanism component 20d. The housing portion 12 that houses the conversion mechanism component 11d in the first gear mechanism 11 forms a separation space K2 that is separated from the oil chamber R1 of the second gear mechanism 20 by an oil seal 16c.

[0181] According to this structure, the first gear mechanism 11, which is operated by the steering shaft 3, is lubricated with grease because of its low rotational speed. By separating the housing portion 12 of the first gear mechanism 11 from the oil chamber R1 of the second gear mechanism 20, the overall oil volume of the device can be reduced, resulting in weight reduction, and the friction caused by oil churning can be reduced, thereby improving workability.

[0182] A sensor 19 for detecting steering torque and speed is installed in the first gear mechanism 11. When the housing 12 of the first gear mechanism 11 is in communication with the oil chamber R1, measures such as an oil seal dedicated to the sensor 19 are required. In contrast, when the housing 12 of the first gear mechanism 11 is separated from the oil chamber R1 of the second gear mechanism 20, a simpler oil seal can be used.

[0183] Additionally, in the steering unit 10, the drive unit 65 is connected to the second gear mechanism 20 via a belt-type transmission mechanism 70. The transmission housing 71 of the transmission mechanism 70 forms a second separation space K3 that is separated from the oil chamber R1 of the second gear mechanism 20 by a second oil seal (oil seal 45c and O-ring 37c1).

[0184] According to this structure, since the transmission mechanism 70 connecting the drive unit 65 and the second gear mechanism 20 is a belt type, the effect of backlash can be suppressed compared to the case where a gear-type transmission mechanism 70 is used. Moreover, since the number of parts can be reduced, weight reduction and improved working accuracy can be achieved.

[0185] By separating the transmission housing 71 of the transmission mechanism 70 from the oil chamber R1 of the second gear mechanism 20, the overall oil volume of the device can be reduced, resulting in weight reduction. Furthermore, friction caused by oil agitation can be reduced, improving workability. In the case of an oil-free transmission mechanism 70, the oil seal on the drive unit 65 side can also be reduced.

[0186] Furthermore, in the steering unit 10, when viewed from the second axis F2, the first output shaft 16 of the first gear mechanism 11 is positioned away from the second gear mechanism 20. The top end of the first output shaft 16 is covered by a cover 72a mounted on the housing portion 12. The cover 72a has a bulge 72c that bulges out along the second axis F2 and bulges toward the transmission mechanism 70 side in the second axis F2.

[0187] According to this structure, the cover 72a covering the top end of the first output shaft 16 of the first gear mechanism 11 has a bulge 72c that bulges out along the second axial direction F2 and bulges axially toward the transmission mechanism 70. This allows a space communicating with the oil chamber R1 of the second gear mechanism 20 to be formed inside the cover 72a. Consequently, a space communicating with the oil chamber R1 can be formed away from the second gear mechanism 20 when viewed from the second axial direction F2. Therefore, the proportion of the space to the overall volume of the oil chamber can be ensured, thus improving reliability.

[0188] (Modified Example)

[0189] FIG. 11 This is a diagram showing the steering unit 10 viewed from the second axis F2, illustrating a modified example with a changed configuration of the drive unit 65.

[0190] like FIG. 11 As shown, the steering unit 10 can easily change the configuration of the drive unit 65 according to the vehicle's configuration space, etc. Therefore, when viewed from the second axis F2, the drive unit 65 (and controller 68) can be configured to move circumferentially within the circular second gear mechanism 20.

[0191] (Other variations)

[0192] FIG. 12A This is a perspective view showing a first variant of the configuration of controller 68. FIG. 12B This is a perspective view showing a second variant of the controller 68.

[0193] FIG. 12A The controller 68' shown is disposed on the outer side of the housing cover 73 of the transmission housing 71 of the transmission mechanism 70. In this case, the area of ​​the outer side of the transmission housing 71 is easily ensured, and therefore, it is easy to install multiple drive circuits in the controller 68.

[0194] FIG. 12B The controller 68 shown is configured in multiple (e.g., two) segments around the periphery of the drive unit 65. Dividing the controller 68 into smaller segments is suitable for situations where a large configuration space cannot be guaranteed.

[0195] While some embodiments of the invention have been described, these embodiments are illustrated by way of example and are not intended to limit the scope of the invention. New embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Embodiments and their variations are included within the scope and spirit of the invention, and are included within the scope of the invention as set forth in the claims and its equivalents.

[0196] For components composed of multiple objects in the embodiments disclosed in this specification, the multiple objects can also be integrated, or conversely, a component composed of a single object can be divided into multiple objects. Whether or not they are integrated, as long as they are configured to achieve the purpose of the invention.

Claims

1. A steering apparatus, wherein the steering apparatus is provided with: a first gear mechanism that is input with a rotation of a steering wheel operation, converts a direction of the rotation, and outputs the rotation as a primary rotation; and a second gear mechanism that is input with the primary rotation output from the first gear mechanism, decelerates the primary rotation, and outputs, the first gear mechanism is provided with: a conversion mechanism member that converts the direction of the rotation; and a housing portion that houses the conversion mechanism member, the second gear mechanism is provided with: a deceleration mechanism member that decelerates the primary rotation; an output shaft that decelerates and outputs the primary rotation; and a gear housing that houses the deceleration mechanism member, a flange portion that forms a side portion in the gear housing toward an axial direction of the output shaft is provided in the gear housing, the flange portion and the housing portion are integrally formed with each other.

2. The steering apparatus according to claim 1, wherein the steering apparatus is provided with: a plurality of fasteners that fix a housing main body of the gear housing to the flange portion; and a gasket plate that is disposed between the flange portion and the plurality of fasteners, and is fixed between a seating surface of the plurality of fasteners and the flange portion by screwing in of the plurality of fasteners, the gasket plate is formed to a size that allows the seating surface of at least two of the plurality of fasteners to contact.

3. The steering apparatus according to claim 1 or 2, wherein the steering apparatus is provided with a drive apparatus that has a drive shaft that outputs a drive force that assists the steering wheel operation, a controller is provided at an end portion of the drive apparatus, the controller is disposed so as to overlap the drive apparatus in an axial direction of the drive shaft, and controls driving of the drive apparatus, when viewed in the axial direction of the drive shaft, the controller is formed in a flat shape with an outer diameter that is larger than an outer diameter of the drive apparatus, thereby suppressing a thickness of the drive apparatus in the axial direction of the drive shaft. ​

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