Steering mechanism motor support structure

Abstract

The motor support structure of the steering device includes: a rack; a rack housing that houses the rack; and a power generating unit that generates power to move the rack. The power generating unit includes: a motor having an output shaft extending axially along the rack at one end; motor peripheral components disposed at the other end of the motor; and a first fastener having a first bolt that axially fastens the motor and the motor peripheral components. The rack housing has a first support portion supporting one end of the power generating unit and a second support portion supporting the other end of the power generating unit. The second support portion has a top end portion connected to the other end of the power generating unit. The top end portion of the second support portion has a first hole through which the shank of the first bolt passes and is fastened together with the motor and the motor peripheral components by the first fastener.

Description

Technical Field

[0001] This invention relates to a motor support structure for a steering device. Background Technology

[0002] As a type of steering system, there exists an electric power steering system. This electric power steering system includes a motor to assist the driver's steering operations. Furthermore, among electric power steering systems, there is a rack-assisted type that inputs the auxiliary force generated by the motor to a rack. Such a rack-assisted type electric power steering system includes a rack housing that houses the rack. The rack housing is fixed to the vehicle body. The motor is supported on the rack housing. Hereinafter, in conventional motor support structures, the rack housing only supports the end of the motor where the output shaft is located. The structure in which only one end of the motor is supported will be referred to as a cantilever structure.

[0003] In cantilever structures, the support strength for the motor is relatively low. Therefore, the part supporting the motor may deform or break. In addition, there is a possibility that vibrations from vehicle operation may cause the motor to emit abnormal noises. For these reasons, Patent Document 1 proposes a double-support structure that supports both ends of the motor.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-174615 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] According to the double-support structure in Patent Document 1, the support portion supporting the other end of the motor is connected to the motor by bolts. Therefore, bolts are required, leading to an increase in the number of components. Furthermore, internal threaded holes for bolt threading are needed; in other words, internal threaded holes need to be machined into the motor. This results in an increase in the manufacturing time of the steering mechanism.

[0009] The present invention was made in view of the above-mentioned problems, and its object is to provide a motor support structure for a steering device that can reduce the number of parts and manufacturing time.

[0010] Solution for solving the problem

[0011] To achieve the above objectives, one technical solution of the present invention provides a motor support structure for a steering device, wherein the motor support structure comprises: a rack; a rack housing housing the rack; and a power generating unit that generates power to move the rack. The power generating unit comprises: a motor having an output shaft extending axially along the rack at one end; a motor peripheral component disposed at the other end of the motor; and a first fastener having a first bolt that axially fastens the motor and the motor peripheral component. The rack housing has a first support portion supporting one end of the power generating unit and a second support portion supporting the other end of the power generating unit. The second support portion has a top end portion connected to the other end of the power generating unit. The top end portion of the second support portion has a first hole through which the shank of the first bolt passes. The top end portion of the second support portion, together with the motor and the motor peripheral component, is fastened by the first fastener.

[0012] By tightening the first fastener, the top end of the second support portion is connected to the other end of the power generation portion. In other words, the fastener that connects the motor and its peripheral components, as well as the fastener that connects the second support portion and the power generation portion, can be used together. Therefore, one fastener is reduced, thereby reducing the number of components. In addition, since one fastener is reduced, the work of setting internal threaded holes in the motor or its peripheral components is reduced, thereby also reducing the manufacturing time of the steering device.

[0013] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, the motor has a first flange protruding from the outer peripheral surface of the other end of the motor and fastened by the first fastener. The motor peripheral component has a cover member that closes the opening at the other end of the motor. The cover member has a second flange that is fastened by the first fastener and abuts against the first flange.

[0014] The fasteners are secured with the first flange and the second flange abutting against each other. In other words, the top end of the second support is not located between the first flange and the second flange. Therefore, it is less likely for a gap to form between the motor and the cover assembly, ensuring the airtightness of the cover assembly.

[0015] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, a magnet is provided on the rotor of the motor. The peripheral components of the motor have a rotation angle sensor that detects changes in the magnetic field of the magnet.

[0016] Because the top end of the second support is not located between the first flange and the second flange, the distance between the rotation angle sensor and the magnet is relatively short. Therefore, the rotation angle sensor can accurately detect changes in the magnetic field of the magnet.

[0017] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, an elastic element is located between the top end of the second support portion and the first flange or the second flange that is adjacent to the top end portion in the axial direction.

[0018] Vibrations transmitted from the first flange or the second flange to the second support are absorbed by the elastic element. Therefore, the second support is less prone to vibration and vibration noise is less likely to be generated.

[0019] In addition, as a desired technical solution for the motor support structure of the aforementioned steering device, an internal threaded hole is provided in the motor or the peripheral component of the motor for threaded engagement of the first bolt.

[0020] The nut that is threaded into the first bolt is not required, thus reducing the number of parts.

[0021] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, the diameter of the first hole is larger than the diameter of the shank of the first bolt.

[0022] One end of the power generating unit is connected to the first support unit. Therefore, the first bolt connected to the power generating unit may shift relative to its predetermined position due to assembly tolerances between the power generating unit and the first support unit. Furthermore, the first hole is larger than the shank of the first bolt, allowing for the aforementioned positional shift of the first bolt. This improves the installability of the second support unit.

[0023] Furthermore, as a desirable technical solution for the motor support structure of the aforementioned steering device, the second support portion is integrally manufactured with the rack housing.

[0024] The bolts connecting the second support and the rack housing are not required, thus reducing the number of parts.

[0025] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, an elastic element is located between the base of the second support portion and the rack housing.

[0026] The vibration transmitted from the rack housing to the strut is absorbed by the elastic element. Therefore, the strut is not prone to vibration and does not easily produce vibration noise.

[0027] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, the second support portion has a base, which is the end opposite to the top portion and has a second hole. The base is fastened to the rack housing by a second bolt.

[0028] The second support and the rack housing are independent of each other, so only the second support can be replaced. Therefore, in cases such as damage to the second support, only the second support can be replaced, which is very convenient.

[0029] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, the rack housing has: a rib protruding from the outer peripheral surface of the rack housing, which increases the strength of the rack housing; and a protrusion protruding from the outer peripheral surface of the rack housing for threaded engagement with the second bolt. The protrusion amount of the protrusion is less than or equal to the protrusion amount of the rib.

[0030] The protrusion of the raised portion is equal to or less than the protrusion of the ribs in the existing structure. Therefore, even if the rack housing has a raised portion, the impact on the mold design of the rack housing (the so-called casting scheme) is small, and the rack housing can be manufactured as before.

[0031] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, the diameter of the second hole is larger than the diameter of the rod portion of the second bolt.

[0032] The second support portion can be moved radially around the shank of the second bolt and fixed to the rack housing. Therefore, positional offsets caused by assembly tolerances can be tolerated, improving the installability of the second support portion.

[0033] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, the second support portion is formed from a long, plate-shaped metal sheet. The first hole and the second hole are formed by penetrating the metal sheet along its thickness direction. The second support portion has an intermediate portion located between the top end and the base. This intermediate portion is twisted, and the orientations of the first hole and the second hole are different.

[0034] The second support portion is plate-shaped, enabling weight reduction. Furthermore, the second support portion has a torsion-type intermediate section, allowing the first hole and the second hole to face different directions. Therefore, it can accommodate both the direction in which the shank of the first bolt penetrates and the direction in which the shank of the second bolt penetrates.

[0035] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, the second support portion is formed from a long, plate-shaped metal sheet. The first hole and the second hole are formed by penetrating the metal sheet along its thickness direction. The second support portion has a middle portion located between the top portion and the base portion. The middle portion is bent, and the orientations of the first hole and the second hole are different.

[0036] The second support portion is plate-shaped, enabling weight reduction. Furthermore, the second support portion has a bent middle section, allowing the first hole and the second hole to face different directions. Therefore, it can accommodate both the direction in which the shank of the first bolt penetrates and the direction in which the shank of the second bolt penetrates.

[0037] Furthermore, as a desired technical solution for the motor support structure of the aforementioned steering device, the second support portion is L-shaped.

[0038] The second support section is relatively short, which increases the support stiffness of the second support section.

[0039] The effects of the invention

[0040] The motor support structure of the steering device according to the present invention enables a reduction in the number of components. Furthermore, it enables a reduction in the manufacturing time of the steering device. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the electric power steering device according to Embodiment 1.

[0042] Figure 2 This is a perspective view of the housing and surrounding area of ​​the electric power steering device in Embodiment 1, which has been extracted and enlarged.

[0043] Figure 3 This is a perspective view of the enlarged central portion of the rack housing in Embodiment 1.

[0044] Figure 4 It is Figure 1 A magnified view of the vicinity of the support bar.

[0045] Figure 5 This is a diagram showing only the support bar extracted from Implementation Method 1.

[0046] Figure 6 yes Figure 4 Sectional view along line VI-VI.

[0047] Figure 7 yes Figure 4 Sectional view along line VII-VII.

[0048] Figure 8 This is an enlarged view of the vicinity of the support bar of the electric power steering device in Embodiment 2.

[0049] Figure 9 This is an enlarged view of the vicinity of the support bar of the electric power steering device in Embodiment 3.

[0050] Figure 10 This is an enlarged view of the vicinity of the support bar of the electric power steering device in Embodiment 4.

[0051] Figure 11 This is an enlarged view of the vicinity of the support bar of the electric power steering device in Embodiment 5.

[0052] Figure 12 This is a cross-sectional view obtained by cutting along the rod portion of the first bolt of the electric power steering device according to embodiment 6.

[0053] Figure 13 This is a cross-sectional view obtained by cutting along the rod portion of the first bolt of the electric power steering device according to embodiment 7.

[0054] Figure 14 This is a cross-sectional view obtained by cutting along the rod portion of the first bolt of the electric power steering device according to embodiment 8.

[0055] Figure 15 This is a cross-sectional view obtained by cutting along the rod portion of the first bolt of the electric power steering device according to embodiment 9. Detailed Implementation

[0056] The present invention will now be described in detail with reference to the accompanying drawings. Furthermore, the present invention is not limited to the embodiments described below. Additionally, the constituent elements in the following embodiments include elements readily conceived by those skilled in the art, substantially the same elements, and elements of equivalent scope. Moreover, the constituent elements disclosed in the following embodiments can be appropriately combined.

[0057] (Implementation Method 1)

[0058] Figure 1 This is a schematic diagram of the electric power steering device according to Embodiment 1. Figure 2 This is a perspective view of the housing and surrounding area of ​​the electric power steering device in Embodiment 1, which has been extracted and enlarged. Figure 3 This is a perspective view of the enlarged central portion of the rack housing in Embodiment 1. Figure 4 It is Figure 2 A magnified view of the vicinity of the support bar. Figure 5 This is a diagram showing only the support bar extracted from Implementation Method 1. Figure 6 yes Figure 4 Sectional view along line VI-VI. Figure 7 yes Figure 4 Sectional view along line VII-VII.

[0059] Electric power steering 1 is a device mounted on the front of a vehicle body to steer the wheels. For example... Figure 1As shown, the electric power steering system 1 includes a steering wheel 81, a steering column shaft 82, a universal joint 83, an intermediate shaft 84, a universal joint 85, a steering pinion 2, a rack and pinion 3, a power generation unit 10, and a reduction gear 20. Figure 1 Not illustrated. See reference. Figure 2 ), shell 30 and support bar 40.

[0060] The steering wheel 81 is connected to the steering column shaft 82. The steering column shaft 82, intermediate shaft 84, and steering pinion 2 are connected via universal joints 83 and 85. The steering pinion 2 meshes with the first rack (not shown) of the rack 3. The rack 3 is movably supported on the housing 30 in the vehicle width direction (in the direction shown by arrows X1 and X2). The two ends 3a and 3b of the rack 3 are connected to wheels (not shown) via steering tie rods 86.

[0061] When the steering wheel 81 is operated by the driver, its operating torque is transmitted to the steering pinion 2, and the steering pinion 2 is driven by the shaft O1 (refer to...). Figure 2 Rotate around the center. As a result, rack and pinion 3 moves in the left-right direction of the vehicle (refer to...). Figure 1 Arrows X1 and X2 are used to steer the wheels. Hereinafter, the direction parallel to the rack 3 will be referred to as the axial direction. The direction pointed to by one end 3a of the rack 3 in the first direction X will be called the first direction X1. The direction pointed to by the other end 3b of the rack 3 in the first direction X will be called the second direction X2.

[0062] The power generation unit 10 is the part that generates the power to move the rack and pinion 3. For example... Figure 2 As shown, the power generation unit 10 includes a motor 11, a motor peripheral component 12, and a first fastener 100. The motor 11 includes an outer cylinder 13, a stator (not shown) disposed inside the outer cylinder 13, a rotor (not shown) rotatably supported inside the stator, and an output shaft 11a integrated with the rotor. The motor 11 is arranged such that the output shaft 11a is parallel to the axial direction. Alternatively, in this invention, the motor 11 may be arranged such that the output shaft 11a extends along an axial direction slightly inclined relative to the axial direction of the rack 3. The motor 11 is arranged such that the output shaft 11a points in a first direction X1. The outer cylinder 13 is cylindrical and has openings (not shown) at its ends in the first direction X1 and the second direction X2. A plurality of one-end flanges 14 are provided at the end of the outer peripheral surface of the outer cylinder 13 in the first direction X1. Additionally, a plurality of other-end flanges 15 are provided at the end of the outer peripheral surface of the outer cylinder 13 in the second direction X2. In addition, the other side flange 15 is sometimes referred to as the first flange.

[0063] The motor peripheral component 12 includes a cover member 16 and a control device (not shown) housed inside the cover member 16. The cover member 16 is disposed in a second direction X2 of the outer cylinder 13. The cover member 16 is provided with a plurality of cover flanges 17 that project radially outward. In addition, the cover flanges 17 are sometimes referred to as second flanges. The cover flanges 17 are disposed in the second direction X2 relative to the other end side flange 15.

[0064] The first fastener 100 is a component used to connect the motor 11 and the motor peripheral component 12. In this embodiment, the first fastener 100 fastens the cover flange 17 towards the other end flange 15, connecting the motor 11 and the motor peripheral component 12. Furthermore, the first fastener 100 in Embodiment 1 has a first bolt 101. In other words, the first fastener 100 consists only of the first bolt 101. The fastening structure based on the first fastener 100 (first bolt 101) will be described later.

[0065] The control device (not shown) receives a detection signal from a torque sensor that detects the input torque input to the steering pinion 2 and controls the output shaft 11a of the motor 11 to output the desired auxiliary torque. The control device includes a rotation angle sensor (not shown) for detecting the rotation angle of the output shaft 11a. This rotation angle sensor detects the rotation angle of the output shaft 11a by sensing changes in the magnetic field of a magnet fixed to the rotor. Other examples of rotation angle sensors include spin valve sensors, AMR (Anisotropic Magneto Resistance) sensors, or Hall effect sensors.

[0066] The reduction gear 20 includes a worm 21 integrated with the output shaft 11a, a worm wheel 22 meshing with the worm 21, and an auxiliary pinion 23 rotating integrally with the worm wheel 22. Furthermore, the auxiliary pinion 23 meshes with a second rack (not shown) provided on the rack 3. Thus, driven by the motor 11, an auxiliary force is applied to the rack 3.

[0067] The housing 30 includes a cylindrical rack housing 31 for accommodating the rack rod 3, a pinion housing 32 for accommodating the steering pinion 2, and a reduction gear housing 33 for accommodating the reduction gear 20.

[0068] The rack housing 31 extends axially along the rack rod 3. Four mounting portions 34 for fixing to the vehicle body are provided on the rack housing 31. A pinion housing 32 is provided at the end of the rack housing 31 in the second direction X2. A reduction gear housing 33 is provided at the end of the rack housing 31 in the first direction X1. Furthermore, a support bar 40 is provided at the center of the rack housing 31 in the axial direction. The number of mounting portions 34 can be arbitrarily determined.

[0069] The reduction gear housing 33 has a motor mounting portion 33a at its end in the second direction X2 of the portion accommodating the worm gear 21. A motor 11 is arranged in the second direction X2 of the motor mounting portion 33a. A bolt 105 passing through one end flange 14 of the motor 11 is threaded into the motor mounting portion 33a. Thus, the end of the power generating portion 10 in the first direction X1 is connected to the reduction gear housing 33. In addition, the opening in the first direction X1 of the outer cylinder 13 is closed by the motor mounting portion 33a. Thus, the end of the power generating portion 10 in the first direction X1 is supported on the rack housing 31 via the reduction gear housing 33. Therefore, in the following description, the reduction gear housing 33 is sometimes referred to as the first support portion.

[0070] like Figure 3 As shown, ribs 35 are formed on the outer peripheral surface 31a of the rack housing 31 to improve the rigidity of the rack housing 31. The ribs 35 extend axially or circumferentially. A raised portion 36 is provided on the outer peripheral surface 31a of the rack housing 31. The raised portion 36 is located at the central portion in the axial direction of the rack housing 31. The raised portion 36 protrudes from the outer peripheral surface 31a and is cylindrical. The end face of the raised portion 36 is the base surface 36a abutted by the base portion 42 of the support bar 40. An internally threaded hole 37 is provided at the central portion of the base surface 36a. Figure 4 As shown, the second bolt 102 is threaded into the internal threaded hole 37.

[0071] like Figure 4 As shown, the support bar 40 is a component that connects the end of the power generating unit 10 in the second direction X2 to the rack housing 31. Furthermore, the center line O2 of the first bolt 101 extends axially. On the other hand, the center line O3 of the threaded second bolt 102 extends radially relative to the axial direction. Therefore, the center lines O2 of the first bolt 101 and O3 of the second bolt 102 are not parallel.

[0072] like Figure 5 As shown, the support bar 40 is formed from a long plate-shaped metal sheet. The support bar 40 has a top portion 41 connected to the power generation unit 10, a base portion 42 connected to the rack housing 31, and a middle portion 43 located between the top portion 41 and the base portion 42.

[0073] The top end 41 has a first circular hole 41a that penetrates the metal sheet along its thickness direction. The base 42 has a second circular hole 42a that penetrates the metal sheet along its thickness direction. The middle part 43 twists as it moves from one end 43a, which is continuous with the top end 41, toward the other end 43b, which is continuous with the base 42, changing the orientation of the metal sheet in the thickness direction.

[0074] With such a support bar 40, for the first hole 41a and the second hole 42a that penetrate the metal sheet along the thickness direction of the metal sheet, one (the first hole 41a) opens along the center line O2 of the first bolt 101, and the other (the second hole 42a) opens along the center line O3 of the second bolt 102, through the intermediate portion 43. Thus, the top end 41 of the support bar 40 is fastened and fixed to the power generating part 10 by the first bolt 101. Furthermore, the base 42 of the support bar 40 is fastened and fixed to the rack housing 31 by the second bolt 102.

[0075] Therefore, the portion of the power generating unit 10 at its end in the second direction X2 is supported on the rack housing 31 via a support bar 40. Therefore, in the following description, the support bar 40 will sometimes be referred to as the second support portion. Next, using... Figure 6 , Figure 7 The fastening structure based on the first bolt 101 and the second bolt 102 will be described in detail.

[0076] like Figure 6 As shown, the top end portion 41 of the support bar 40 is disposed in the second direction X2 of the cover flange 17. That is, the other end side flange 15, the cover flange 17, and the top end portion 41 are disposed sequentially toward the second direction X2. The other end side flange 15 has a hole 15a that extends axially through the other end side flange 15. A threaded groove is provided on the inner circumferential surface of the hole 15a in the other end side flange 15. That is, the hole 15a is an internally threaded hole. Additionally, the cover flange 17 has a hole 17a that extends axially through the cover flange 17. The diameter of the hole 17a is larger than the diameter of the hole 15a, and the hole 17a is a through hole through which the shank portion 101a of the first bolt 101 passes. The first hole 41a of the top end portion 41 is disposed in a manner that overlaps the hole 15a and the hole 17a in the axial direction.

[0077] The shank 101a of the first bolt 101 passes through the first hole 41a and the hole 17a, and is threaded into the hole 15a. Furthermore, the head 101b of the first bolt 101 fastens the top portion 41 and the cover flange 17 towards the other end flange 15. Thus, the first bolt 101 connects the power generation unit 10 (motor 11 and motor peripheral components 12) and the top portion 41 of the support bar 40.

[0078] Furthermore, the end of the power generation unit 10 in the first direction X1 is supported on the reduction gear housing 33 (see reference). Figure 2 Therefore, the first bolt 101, which is threaded onto the other end flange 15 of the power generation section 10, may shift relative to its predetermined position due to assembly tolerances between the power generation section 10 and the reduction gear housing 33. On the other hand, as... Figure 6As shown, the first hole 41a of the top portion 41 is larger than the hole 17a of the cover flange 17. In other words, the first hole 41a is larger than the shank 101a of the first bolt 101. Therefore, even if the shank 101a of the first bolt 101 is radially offset relative to the center line O2, it is permissible. Thus, the installability of the support bar 40 is improved.

[0079] In addition, the shank 101a of the first bolt 101 protrudes from the first surface 15b of the other end flange 15 in a first direction X1. The second surface 15c of the other end flange 15 abuts against the first surface 17b of the cover flange 17. The second surface 17c of the cover flange 17 abuts against the first surface 41b of the top end portion 41. Furthermore, a washer 110 is provided between the second surface 41c of the top end portion 41 and the head 101b to prevent the first bolt 101 from loosening.

[0080] like Figure 7 As shown, the base 42 of the support bar 40 abuts against the base surface 36a of the raised portion 36. Furthermore, the second hole 42a of the base 42 is arranged to overlap with the internal threaded hole 37. The shank 102a of the second bolt 102 passes through the second hole 42a and is threaded into the internal threaded hole 37. The head 102b of the second bolt 102 fastens the base 42 towards the raised portion 36. Thus, the second bolt 102 connects the rack housing 31 and the base 42 of the support bar 40.

[0081] The diameter of the second hole 42a is made larger than the diameter of the shank 102a of the second bolt 102. This allows the support bar 40 to be installed along the centerline O3 of the shank 102a of the second bolt 102 (see reference). Figure 4 Radial movement of the support bar 40. That is, the mounting position of the support bar 40 relative to the rack housing 31 can be adjusted. When the cover flange 17 and the top end 41 of the support bar 40 are axially spaced and a gap is created due to assembly tolerances, the support bar 40 can be moved in the first direction X1 so that the cover flange 17 and the top end 41 of the support bar 40 abut. In other words, positional deviations caused by assembly tolerances can be tolerated, improving the installability of the support bar 40.

[0082] Furthermore, the range of positional offset of the first bolt 101 that can be tolerated by the first hole 41a is radially outward from the centerline O2 of the first bolt 101. On the other hand, the direction in which the position can be adjusted via the second hole 42a is radially outward from the centerline O3 of the second bolt 102, which is different from the orientation of the first hole 41a. Therefore, the installability of the support bar 40 is significantly improved by using the first hole 41a and the second hole 42a.

[0083] Furthermore, the protrusion of the raised portion 36 is less than that of the rib 35. The rack housing 31 is typically formed by casting, but when protrusions with large protrusions are manufactured on the outer peripheral surface, the rack housing 31 becomes difficult to form. Therefore, even if the raised portion 36, whose protrusion is smaller than that of the rib 35 in the conventional structure, is provided in the rack housing 31, the impact on the mold design (so-called casting scheme) of the rack housing 31 is relatively small. Therefore, the rack housing 31 can be manufactured as before. Furthermore, the protrusion of the raised portion 36 of the present invention can also be the same as that of the rib 35. This is because, in this case, the impact on the mold design (so-called casting scheme) of the rack housing 31 is also relatively small, which is also preferable.

[0084] In summary, the motor support structure of the electric power steering device 1 in Embodiment 1 includes a rack 3, a rack housing 31 that houses the rack 3, and a power generating unit 10 that generates power to move the rack 3. The power generating unit 10 includes: a motor 11 having an output shaft 11a extending axially along the rack 3 at one end; a motor peripheral component 12 disposed at the other end of the motor 11; and a first fastener 100 having a first bolt 101, which axially fastens the motor 11 and the motor peripheral component 12. The rack housing 31 has a first support portion (reduction gear housing 33) supporting one end of the power generating unit 10 and a second support portion (support bar 40) supporting the other end of the power generating unit 10. The second support portion (support bar 40) has a top end portion 41 connected to the other end of the motor 11. The top end 41 of the second support (support bar 40) has a first hole 41a through which the rod 101a of the first bolt 101 passes. The top end 41 is fastened together with the motor 11 and the motor peripheral parts 12 by the first fastener 100.

[0085] The top end 41 of the second support (support bar 40) is fastened to the other end of the power generation part 10 (the end position in the second direction X2) by the first fastener 100 (first bolt 101). That is, the fastener that connects the motor 11 and the motor peripheral component 12 and the fastener that connects the second support (support bar 40) and the power generation part 10 can be used together. As a result, one fastener is reduced, thereby reducing the number of parts. In addition, since one fastener is reduced, the work of providing internal threaded holes in the motor 11 or the motor peripheral component 12 is reduced, thereby also reducing the manufacturing time of the electric power steering device 1.

[0086] Additionally, the motor 11 in Embodiment 1 has a first flange (other end flange 15) protruding from the outer peripheral surface of the other end side of the motor 11 and fastened by the first fastener 100. The motor peripheral component 12 has a cover member 16 that closes the opening at the other end side of the motor 11. The cover member 16 has a second flange (cover flange 17) that is fastened by the first fastener 100 and abuts against the first flange (other end flange 15).

[0087] The second support (support bar 40) is not located between the first flange (the flange 15 on the other end) and the second flange (the cover flange 17). Therefore, it is not easy for a gap to be generated between the motor 11 and the cover member 16, and the airtightness of the cover member 16 can be ensured. As a result, foreign objects and liquids are difficult to enter the interior of the motor 11 from the opening on the other end side of the motor 11.

[0088] Furthermore, in Embodiment 1, the rotor of the motor 11 is provided with a magnet. The motor peripheral component 12 has a rotation angle sensor that detects changes in the magnetic field of the magnet.

[0089] As mentioned above, the second support (support bar 40) is not located between the first flange (the other end side flange 15) and the second flange (the cover flange 17), therefore, the distance between the rotation angle sensor and the magnet is relatively short. Thus, the rotation angle sensor can accurately detect changes in the magnetic field of the magnet.

[0090] Furthermore, in Embodiment 1, the motor 11 or the motor peripheral component 12 is provided with an internally threaded hole for threaded engagement of the first bolt 101. Specifically, the hole portion 15a of the flange 15 at the other end of the motor 11 is an internally threaded hole.

[0091] The nut that is threaded into the first bolt 101 is not required, thus reducing the number of parts.

[0092] In addition, the diameter of the first hole 41a in Embodiment 1 is larger than the diameter of the shank 101a of the first bolt 101.

[0093] The first hole 41a allows for radial ( ) of the first bolt 101. Figure 4 The position of the second support (bracket 40) is offset radially from the centerline O2. Therefore, the installability of the second support (bracket 40) is improved.

[0094] Furthermore, the second support portion (support bar 40) in Embodiment 1 has a base portion 42, which is the end opposite to the top portion 41 and is provided with a second hole portion 42a. The base portion 42 is fastened to the rack housing 31 by a second bolt 102.

[0095] Since the second support (support bar 40) is independent of the rack housing 31, only the second support (support bar 40) can be replaced. Therefore, in cases such as damage to the second support (support bar 40), only the second support (support bar 40) can be replaced, which is more convenient.

[0096] Additionally, the rack housing 31 of Embodiment 1 has: a rib 35 protruding from the outer peripheral surface 31a of the rack housing 31, which increases the strength of the rack housing 31; and a protrusion 36 protruding from the outer peripheral surface 31a of the rack housing 31 for threading with the second bolt 102. The protrusion amount of the protrusion 36 is less than or equal to the protrusion amount of the rib 35.

[0097] Although the rack housing 31 has a raised portion 36, the raised portion 36 has little impact on the mold design (so-called casting scheme) of the rack housing. Therefore, the rack housing 31 can be manufactured as before.

[0098] In addition, the diameter of the second hole 42a is larger than the diameter of the shank 102a of the second bolt 102.

[0099] The second support (bracket 40) can be moved radially around the rod portion 102a of the second bolt 102 and fixed to the rack housing 31. Therefore, positional deviations caused by assembly tolerances can be tolerated, improving the installability of the second support (bracket 40).

[0100] Furthermore, in Embodiment 1, the second support portion (support bar 40) is formed from a long plate-shaped metal sheet. The first hole 41a and the second hole 42a are formed by penetrating the metal sheet along its thickness direction. The second support portion (support bar 40) has a middle portion 43 located between the top portion 41 and the base portion 42. The middle portion 43 is twisted, and the orientations of the first hole 41a and the second hole 42a are different.

[0101] Therefore, since the second support portion (support bar 40) is plate-shaped, weight reduction can be achieved. Furthermore, since the second support portion (support bar 40) has a torsional intermediate portion 43, the orientation of the first hole 41a and the orientation of the second hole 42a can be different. Therefore, it is possible to accommodate both the direction in which the shank 101a of the first bolt 101 penetrates and the direction in which the shank 102a of the second bolt 102 penetrates.

[0102] Next, other embodiments of the motor support structure of the electric power steering device of the present invention will be described. Furthermore, in the following description, the same reference numerals are used for components that are the same as those described in Embodiment 1 above, and repeated descriptions are omitted.

[0103] (Implementation Method 2)

[0104] Figure 8 This is an enlarged view showing the vicinity of the support bar in the electric power steering device of Embodiment 2. The electric power steering device 1A of Embodiment 2 differs from the electric power steering device 1 of Embodiment 1 in that it has a support bar 40A instead of the support bar 40. Hereinafter, the differences will be mainly explained.

[0105] The support bar 40A, serving as the second support portion, has an intermediate portion 43A located between the top end portion 41 and the base portion 42. Both the connecting portion 43A to the top end portion 41 and the connecting portion 44 to the base portion 42 are bent. The connecting portion 44 is a bent line in an inclined direction relative to the metal sheet constituting the support bar 40A. By using the connecting portion 44 formed by this inclined bent line, a first hole is formed in the metal sheet along the thickness direction. Figure 8 (not shown in the diagram) and the second hole ( Figure 8 (Not shown in the image) These two have different orientations.

[0106] According to this embodiment 2, the intermediate portion 43A can handle both the direction in which the shank 101a of the first bolt 101 penetrates and the direction in which the shank 102a of the second bolt 102 penetrates.

[0107] (Implementation Method 3)

[0108] Figure 9 This is an enlarged view of the vicinity of the support bar in the electric power steering device of Embodiment 3. The electric power steering device 1B of Embodiment 3 differs from the electric power steering device 1 of Embodiment 1 in that it includes a support bar 40B instead of the original support bar 40. Furthermore, in Embodiment 2, the middle portion 43B and the top portion 41 of the support bar 40B are on the same plane. That is, the middle portion 43B is a plane perpendicular to the center line O3 of the rod portion 101a of the first bolt 101. Additionally, the connecting portion 45 where the middle portion 43B connects to the base portion 42 is bent at a right angle. Even with this support bar 40B, the first hole formed by penetrating the metal sheet along the thickness direction of the metal sheet (…) Figure 9 (not shown in the diagram) and the second hole ( Figure 9 (Not shown in the image) These two have different orientations.

[0109] (Implementation Method 4)

[0110] Figure 10 This is an enlarged view showing the vicinity of the support bar in the electric power steering device of Embodiment 4. The electric power steering device 1C of Embodiment 4 differs from the electric power steering device 1 of Embodiment 1 in that it has a support bar 40C instead of a support bar 40.

[0111] The middle portion 43C of the support bar (second support portion) 40C is a connecting portion that connects the top portion 41 and the base portion 42 in a 90° bend. Therefore, the support bar 40C is shorter than the support bars 40, 40A, and 40B of Embodiments 1 to 3, and the support stiffness of the support bar 40C supporting the other end of the power generation portion 10 is higher. Furthermore, when using such a support bar 40C, it is necessary to position the raised portion 36 so that the center line O2 of the first bolt 101 and the center line O3 of the second bolt 102 are in the same plane and orthogonal to each other.

[0112] (Implementation Method 5)

[0113] Figure 11 This is an enlarged view showing the vicinity of the support bar in the electric power steering device of Embodiment 5. The electric power steering device 1D of Embodiment 5 differs from the electric power steering device 1 of Embodiment 1 in that it has a support bar 40D instead of a support bar 40.

[0114] The support bar 40D, serving as the second support portion, is integrally manufactured with the rack housing 31. That is, the base 42D of the support bar 40D is continuous with the outer peripheral surface 31a of the rack housing 31. Furthermore, the middle portion 43D of the support bar 40D is a plane perpendicular to the center line O2 of the first bolt 101. Therefore, the support bar 40D itself is flat. As a result, a second bolt connecting the support bar 40D, serving as the second support portion, to the rack housing 31 is unnecessary, thereby reducing the number of components.

[0115] (Implementation Method 6)

[0116] Figure 12 This is a cross-sectional view obtained by cutting along the shank of the first bolt of the electric power steering device of Embodiment 6. The electric power steering device 1E of Embodiment 6 differs from the electric power steering device 1 of Embodiment 1 in that the first fastener 100 has a nut 103.

[0117] The first fastener 100 includes a first bolt 101 and a nut 103. The nut 103 is disposed on the first surface 15b of the other end flange 15 in a first direction X1. The shank 101a of the first bolt 101 passes through the top end 41 of the support bar 40, the cover flange 17, and the other end flange 15, and is threadedly engaged with the nut 103. Thus, the top end 41, the cover flange 17, and the other end flange 15 are fastened by the head 101b of the first bolt 101 and the nut 103. Furthermore, since the hole 15a of the other end flange 15 is not threadedly engaged with the shank 101a, the diameter of the hole 15a is formed to be larger than the diameter of the shank 101a. Therefore, the first fastener 100 can also include a first bolt 101 and a nut 103.

[0118] (Implementation Method 7)

[0119] Figure 13 This is a cross-sectional view obtained by cutting along the shank of the first bolt of the electric power steering device of Embodiment 7. The electric power steering device 1F of Embodiment 7 differs from the electric power steering device 1 of Embodiment 1 in that the orientation of the first bolt 101 is different. Furthermore, the top end 41 of the support bar 40 is disposed in the first direction X1 of the other end flange 15. The hole 15a of the other end flange 15 is a through hole, and the hole 17a of the cover flange 17 is an internally threaded hole. The first bolt 101 is inserted from the first direction X1 of the other end flange 15 into the first hole 41a of the top end 41, and is threaded into the hole 17a of the cover flange 17 through the hole 15a of the other end flange 15. Furthermore, the head 101b of the first bolt 101 is tightened towards the second direction X2 to secure the top end 41 and the other end flange 15. Therefore, in this invention, the insertion direction of the first bolt 101 is not particularly limited.

[0120] (Implementation Method 8)

[0121] Figure 14 This is a cross-sectional view obtained by cutting along the shank of the first bolt of the electric power steering device of Embodiment 8. The electric power steering device 1G of Embodiment 8 differs from the electric power steering device 1 of Embodiment 1 in that the top end 41 of the support bar 40 is located between the other end flange 15 and the cover flange 17. In this electric power steering device 1G of Embodiment 8, the top end 41 of the support bar 40 can be fixed to the other end of the power generation unit 10. Furthermore, when the top end 41 of the support bar 40 is located between the other end flange 15 and the cover flange 17, the outer cylinder 13 of the motor 11 and the cover member 16 are axially separated. Therefore, a design change is needed to enable the cover member 16 to seal the opening in the second direction X2 of the outer cylinder 13.

[0122] (Implementation Method 9)

[0123] Figure 15 This is a cross-sectional view obtained by cutting along the shank of the first bolt of the electric power steering device of Embodiment 9. The electric power steering device 1H of Embodiment 9 differs from the electric power steering device 1 of Embodiment 1 in that the elastic member 50 is located between the top end 41 of the support bar 40 and the cover flange 17 adjacent to the top end 41 in the axial direction. The elastic member 50 has an annular hole 51 through which the shank 101a passes.

[0124] In summary, in embodiment 8, the elastic member 50 is located between the top end portion 41 of the support bar 40, which serves as the second support portion, and the other end flange (first flange) 15 or the second flange (cover flange) 17 adjacent to the top end portion 41 in the axial direction. With this structure, vibrations transmitted from the other end flange 15 or the cover flange 17 to the support bar 40 are absorbed by the elastic member 50. Therefore, the support bar 40 is less prone to vibration and less likely to produce vibration noise.

[0125] In summary, electric power steering devices 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, and 1H according to embodiments 1 to 9 have been described, but the present invention is not limited to the examples described in the embodiments. For example, although the motor 11 and the motor peripheral component 12 have flanges (the other end flange 15 and the cover flange 17) fastened by the first fastener 100, the present invention may not have such flanges. That is, the shank 101a of the first bolt 101 may also penetrate the end face of the cover member 16 in the second direction X2 and be threaded with the internal thread provided inside the outer cylinder 13 of the motor 11. Even in such an example, it is possible to reduce the number of components and the manufacturing time of the electric power steering device. In addition, the reduction device 20 of the electric power steering device may also be a device that combines a pulley device (including a drive pulley, a driven pulley, and a belt) and a ball screw device. It is also possible that the cross-sectional shape of the first hole 41a and the second hole 42a is not circular, but elongated. In other words, the reason is that even when the first hole 41a and the second hole 42a are elongated holes, positional offsets caused by assembly tolerances can be tolerated. Furthermore, the motor support structure shown in this invention can also be applied to a so-called single-pinion type electric power steering system that imparts torque to the motor 11 relative to the steering pinion 2.

[0126] Alternatively, the elastic element 50 may be positioned between the base 42 of the support bar 40 and the raised portion 36 of the rack housing 31. Thus, vibrations transmitted from the rack housing 31 to the support bar 40 are absorbed by the elastic element 50. Consequently, the support bar 40 is less prone to vibration and noise. Furthermore, while an example of its application in an electric power steering system has been given in this embodiment, the steering device of the present invention can also be applied to a steer-by-wire system. That is, the present invention can also be applied to a support structure in a steer-by-wire system that supports a steering drive (motor) that drives the rack in accordance with steering operations.

[0127] Explanation of reference numerals in the attached figures

[0128] 1. 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, Electric power steering (steering device); 2. Steering pinion; 3. Rack; 10. Power generation unit; 20. Reduction gear; 30. Housing; 11. Motor; 11a. Output shaft; 12. Motor peripheral components; 13. Outer cylinder; 15. Side flange at the other end (first flange); 16. Cover component; 17. Cover flange (second flange); 23. Auxiliary pinion; 31. Rack housing; 33. Reduction gear housing ( 35. Rib; 36. Raised portion; 40, 40A, 40B, 40C, 40D, Support bar (2nd support portion); 41. Top end portion; 41a. 1st hole portion; 42, 42D. Base portion; 42a. 2nd hole portion; 43, 43A, 43B, 43C, 43D. Middle portion; 50. Elastic element; 100. 1st fastener; 101. 1st bolt; 101a. Rod portion; 101b. Head; 102. 2nd bolt; 102a. Rod portion; 103. Nut.

Claims

1. A motor support structure for a steering device, wherein, The motor support structure of the steering device includes: rack and pinion; Rack housing, which accommodates the rack bar; and The power generation unit generates the power to move the rack and pinion. The power generation unit includes: A motor having an output shaft extending axially along the rack at one end; Motor peripheral components, which are disposed on the other end side of the motor; and A first fastener, having a first bolt, secures the motor and the motor peripheral components in the axial direction. The rack housing has a first support portion that supports one end of the power generating unit and a second support portion that supports the other end of the power generating unit. The second support portion has a top end portion that is connected to the other end of the power generation portion. The top end of the second support has a first hole through which the shank of the first bolt passes and is fastened together with the motor and the motor peripheral components by the first fastener. The motor has a first flange that protrudes from the outer peripheral surface of the other end of the motor and is fastened by the first fastener. The motor peripheral components have a cover member that closes the opening at the other end of the motor. The cover member has a second flange that is fastened to the first flange by the first fastener and abuts against the first flange. The rotor of the motor is provided with a magnet, and the peripheral components of the motor have a rotation angle sensor for detecting changes in the magnetic field of the magnet.

2. The motor support structure of the steering device according to claim 1, wherein, The elastic element is located between the top end of the second support portion and the first flange or the second flange that is adjacent to the top end portion in the axial direction.

3. The motor support structure of the steering device according to claim 1, wherein, The motor or the peripheral components of the motor are provided with an internal threaded hole for the first bolt to be threaded into.

4. The motor support structure of the steering device according to claim 1, wherein, The diameter of the first hole is larger than the diameter of the shank of the first bolt.

5. The motor support structure of the steering device according to claim 1, wherein, The second support portion is integrally manufactured with the rack housing.

6. The motor support structure of the steering device according to claim 1, wherein, The second support portion has a base portion, which is the end portion opposite to the top portion, and is provided with a second hole portion. The base is fastened to the rack housing by the second bolt.

7. The motor support structure of the steering device according to claim 6, wherein, The elastic element is located between the base of the second support and the rack housing.

8. The motor support structure of the steering device according to claim 6, wherein, The rack housing has: A rib protruding from the outer peripheral surface of the rack housing, the rib increasing the strength of the rack housing; and A raised portion protrudes from the outer peripheral surface of the rack housing for threaded engagement of the second bolt. The amount of protrusion of the raised portion is less than or equal to the amount of protrusion of the rib.

9. The motor support structure of the steering device according to any one of claims 6 to 8, wherein, The diameter of the second hole is larger than the diameter of the shank of the second bolt.

10. The motor support structure of the steering device according to any one of claims 6 to 8, wherein, The second support portion is formed by shaping a long, plate-shaped metal sheet. The first hole and the second hole are formed by penetrating the metal sheet along its thickness direction. The second support portion has a middle portion located between the top portion and the base portion. The middle part is twisted, and the orientation of the first hole is different from that of the second hole.

11. The motor support structure of the steering device according to any one of claims 6 to 8, wherein, The second support portion is formed by shaping a long, plate-shaped metal sheet. The first hole and the second hole are formed by penetrating the metal sheet along its thickness direction. The second support portion has a middle portion located between the top portion and the base portion. The middle part is bent, and the orientation of the first hole is different from that of the second hole.

12. The motor support structure of the steering device according to claim 11, wherein, The second support portion is L-shaped.

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