Electric power steering device

Abstract

To provide an electric power steering device that includes a reducer housing that can be formed by casting with a further smaller number of molds.SOLUTION: An electric power steering device includes a reducer housing which includes at least either one of a worm shaft housing or a worm wheel housing, and which is a cast product. A plurality of hooks that restricts the position of a harness is provided on the outer surface of the reducer housing. The plurality of hooks is arranged along a parting line extending in a Y-direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electric power steering device. [Background technology]

[0002] Patent Document 1 discloses a reducer housing including a sensor housing that houses a torque sensor. The sensor housing has a through hole, and a harness connected to the torque sensor is pulled out to the outside of the sensor housing through the through hole. A resin clip is attached to the sensor housing, and the position of the harness is regulated by the clip.

[0003] However, since the clip may be damaged when subjected to external force, such as when it is struck by another vehicle part, during vehicle assembly, a harness position restricting portion with higher rigidity is desired.

[0004] Therefore, for example, by forming the hook using a casting, it is possible to form a hook having higher rigidity. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-56943 A Summary of the Invention [Problem to be solved by the invention]

[0006] Here, the hooks protrude from the outer surface of the reducer housing, and multiple hooks must be provided. Therefore, in order to prevent the casting mold from getting caught on the hooks when opening the mold, the casting mold is divided into multiple molds, and the multiple divided molds are moved in multiple directions to open the casting mold. In this way, when a reducer housing provided with hooks is molded by casting, the number of casting molds increases, which may complicate the manufacturing process.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide an electric power steering device including a reducer housing that can be molded using a casting mold having fewer molds. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, an electric power steering device of one embodiment of the present disclosure includes a reducer housing made of a casting, and includes at least one of a worm shaft housing that accommodates a worm shaft attached to an output shaft of a motor and a worm wheel housing that accommodates a worm wheel that meshes with the worm shaft, and the reducer housing has an outer surface with a plurality of hooks that protrude from the outer surface, extend to one side in a first direction, and regulate the position of a harness, and the plurality of hooks are arranged along a parting line that extends in a second direction that intersects the first direction.

[0009] As described above, the reducer housing of Patent Document 1 is provided with a resin clip, and a harness is attached to the clip. However, during vehicle assembly, the clip may be damaged when subjected to external force, such as when it is struck by another vehicle part, and therefore a highly rigid hook formed, for example, by casting is desired. However, when a reducer housing having a hook is formed by casting, the casting mold needs to be divided into many parts so that the mold does not get caught on the hook when it is opened.

[0010] Therefore, in the present disclosure, a plurality of hooks are provided and arranged along the parting line. This allows a casting mold to be configured with two molds, for example, a first mold located on one side of the parting line and a second mold located on the other side of the parting line. Then, some of the plurality of hooks can be molded in the first mold, and the remaining hooks can be molded in the second mold. In this way, according to the present disclosure, it is possible to mold a reducer housing having hooks by casting using a casting mold having fewer molds.

[0011] In a desirable embodiment, the hook is a key hook equipped with a position regulating portion in which a U-shaped notch is provided when viewed from the second direction, and the position of the harness inserted through the opening of the notch is regulated by the position regulating portion, and the multiple key hooks include a first key hook, a second key hook and a third key hook arranged in order from one side to the other side of the second direction, and the opening of the notch in the first key hook faces one side of a third direction intersecting the first direction and the second direction, the opening of the notch in the second key hook faces the other side of the third direction, and the opening of the notch in the third key hook faces one side of the third direction.

[0012] In a mode in which the openings are arranged in the same direction in the third direction from the first key hook to the third key hook, the harness may come off from the direction in which the openings are facing. However, in the present disclosure, the openings of the key hooks are arranged alternately in the third direction from the first key hook to the third key hook. Therefore, in the present disclosure, the harness is less likely to come off from multiple key hooks. In this way, the openings of the key hooks are arranged alternately in the third direction from the first key hook to the third key hook. Therefore, compared to a mode in which the openings are arranged in the same direction in the third direction from the first key hook to the third key hook, the harness whose position is restricted by the key hook is curved left and right when viewed from the first direction, so that the position restriction force of the harness by the key hook is stronger.

[0013] As a desirable aspect, when viewed from the first direction, the parting line is located on the other side of the third direction relative to the first key hook, on one side of the third direction relative to the second key hook, and on the other side of the third direction relative to the third key hook.

[0014] Since the harness is inserted into the cutout, if burrs or the like occur around the edge of the cutout, the harness may be damaged. However, in the present disclosure, the parting line does not overlap with the cutout when viewed from the first direction, so that the occurrence of burrs or the like around the edge of the cutout is suppressed.

[0015] In a preferred embodiment, the parting line is linear when viewed from the first direction. This allows the mating portion of the casting mold to have a flat surface. That is, the edges of the first mold and the second mold are linear when viewed from the first direction, making it easier to manufacture the casting mold. In addition, the flat surface of the mating portion of the casting mold has the advantage of improving the sealing of the mating portion of the casting mold.

[0016] In a preferred embodiment, a first height of the first key hook from the outer surface along the first direction is different from a second height of the second key hook and is the same as a third height of the third key hook.

[0017] Therefore, when viewed from the third direction, the harness whose position is restricted by the first key hook, the second key hook, and the third key hook has a gentle U-shape. In contrast, when the first height, the second height, and the third height are all the same, the harness has a straight line when viewed from the third direction. Therefore, according to the present disclosure, the degree of bending of the harness by the first key hook, the second key hook, and the third key hook becomes greater, and the position restriction force of the harness by the key hooks becomes stronger.

[0018] In a preferred embodiment, a first distance between the first key hook and the second key hook in the second direction is different from a second distance between the second key hook and the third key hook in the second direction.

[0019] Therefore, for example, when the second distance is smaller than the first distance, the portion of the harness located between the second key hook and the third key hook will bend more when viewed from the first direction than the portion of the harness located between the first key hook and the second key hook. Therefore, the force of the key hooks to restrict the position of the harness is stronger than in an embodiment in which the first key hook, the second key hook, and the third key hook are arranged at equal intervals in the second direction.

[0020] In a preferred embodiment, the hook is a columnar hook protruding from the outer surface to one side in the first direction, the columnar hook having a cylindrical small diameter portion and a cylindrical large diameter portion provided on one side in the first direction of the small diameter portion and having a larger diameter than the small diameter portion, and the position of the harness is regulated by the small diameter portion.

[0021] In this way, since the position of the harness is restricted by the cylindrical small diameter portion, the harness may be abutted on either the right side or the left side of the small diameter portion, which makes it easier to restrict the position of the harness with the pillar-shaped hook.

[0022] In a preferred embodiment, when a direction intersecting the first direction and the second direction is a third direction, the plurality of columnar hooks are arranged in a straight line extending in the second direction as viewed from the first direction, and the parting line is straight and passes through the center of the plurality of columnar hooks in the third direction. This makes it difficult for the first and second dies to get caught on the columnar hooks when the casting mold is opened, facilitating the molding operation of the reducer housing.

[0023] In a preferred embodiment, the plurality of post-shaped hooks include a first post-shaped hook, a second post-shaped hook, and a third post-shaped hook arranged in order from one side to the other side in the second direction, and a first distance between the first post-shaped hook and the second post-shaped hook in the second direction is different from a second distance between the second post-shaped hook and the third post-shaped hook in the second direction. Therefore, according to the present disclosure, the degree of bending of the harness whose position is restricted by the first post-shaped hook, the second post-shaped hook, and the third post-shaped hook becomes larger when viewed from the first direction, and the force of restricting the position of the harness by the post-shaped hooks becomes stronger. Effect of the Invention

[0024] According to the present disclosure, it is possible to provide an electric power steering device including a reducer housing that can be molded using a casting mold having fewer dies. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram of a steering device according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of the steering force assist mechanism of the first embodiment. [Diagram 3] FIG. 3 is a perspective view of the hook of the first embodiment. [Figure 4] FIG. 4 is a side view of the steering force assist mechanism of the first embodiment. [Diagram 5] FIG. 5 is a schematic front view of the steering force assist mechanism of the first embodiment. [Figure 6A] FIG. 6A is an enlarged perspective view of the hook of the first embodiment. [Figure 6B] FIG. 6B is an enlarged perspective view of the hook of the first embodiment. [Figure 7] FIG. 7 is a schematic diagram showing a worm shaft housing and a casting mold. [Figure 8] FIG. 8 is a side view of the steering force assist mechanism according to the first modified example of the first embodiment. [Figure 9] FIG. 9 is a perspective view of a hook according to the first modification of the first embodiment. [Figure 10] FIG. 10 is a front view of the steering force assist mechanism according to the second modification of the first embodiment. [Figure 11] FIG. 11 is a perspective view of a hook according to the third modification of the first embodiment. [Figure 12] FIG. 12 is a front view of the steering force assist mechanism of the second embodiment. [Figure 13] FIG. 13 is a perspective view of a hook according to the second embodiment. [Figure 14] FIG. 14 is a perspective view of a hook according to the second embodiment. [Figure 15] FIG. 15 is a perspective view of the steering force assist mechanism of the third embodiment. [Figure 16] FIG. 16 is a perspective view of a hook according to the third embodiment. [Figure 17] FIG. 17 is a front view of the steering force assist mechanism of the third embodiment. [Figure 18] FIG. 18 is a perspective view of a hook according to the third embodiment. [Figure 19] FIG. 19 is a perspective view of a hook according to the third embodiment. [Figure 20] FIG. 20 is a front view of the steering force assist mechanism according to the first modified example of the third embodiment. [Figure 21] FIG. 21 is a side view of the steering force assist mechanism of the fourth embodiment. [Figure 22] FIG. 22 is a front view of the steering force assist mechanism of the fourth embodiment. [Diagram 23] FIG. 23 is a perspective view of the steering force assist mechanism of the fourth embodiment. [Figure 24] FIG. 24 is a perspective view of the steering force assist mechanism of the fourth embodiment. [Diagram 25] FIG. 25 is a front view of the steering force assist mechanism of the fourth embodiment. [Figure 26] FIG. 26 is a side view of the steering force assist mechanism of the fifth embodiment. [Figure 27] FIG. 27 is a front view of the steering force assist mechanism of the fifth embodiment. [Figure 28] FIG. 28 is a front view of the steering force assist mechanism of the fifth embodiment. [Figure 29] FIG. 29 is a perspective view of the steering force assist mechanism of the fifth embodiment. [Diagram 30] FIG. 30 is a perspective view of a hook according to the fifth embodiment. [Diagram 31] FIG. 31 is a perspective view of a hook according to the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the following modes for carrying out the invention (hereinafter, referred to as embodiments). Furthermore, the components in the following embodiments include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be appropriately combined.

[0027] In the following, the first to third embodiments show an embodiment in which a hook is provided on a worm shaft housing, and the fourth and fifth embodiments show an embodiment in which a hook is provided on a worm wheel housing. The first, second, fourth and fifth embodiments show an embodiment in which the hook is a key hook, and the third embodiment shows an embodiment in which the hook is a columnar hook. Furthermore, the first and fourth embodiments show an embodiment in which the parting line is non-linear, and the second, third and fifth embodiments show an embodiment in which the parting line is linear. In the present invention, the number of hooks is set to three, but three or more hooks may be provided.

[0028] Furthermore, in the following embodiment, a hook is provided on the reducer housing in a column type steering device, but the present invention is not limited to this and also includes an embodiment in which a hook is provided on the reducer housing in a single pinion type or dual pinion type steering device.

[0029] In the first to third embodiments, the X direction in the drawings is the first direction. The X direction is parallel to the radial direction of the central axis AX1. The X1 side is one side of the first direction and is opposite to the X2 side (the other side). The Y direction is the second direction. The Y direction is perpendicular to (intersects) the X direction. The Y direction is parallel to the axial direction of the central axis AX1. The Y1 side is one side of the second direction and is opposite to the Y2 side (the other side). The Z direction is the third direction. The Z direction is perpendicular to (intersects) the X and Y directions. The Z1 side is one side of the third direction and is opposite to the Z2 side (the other side).

[0030] In the fourth and fifth embodiments, the x direction in the drawings is the first direction. The x direction is parallel to the radial direction of the central axis AX2. The x1 side is one side of the first direction and is opposite to the x2 side (the other side). The y direction is the second direction. The y direction is perpendicular to (intersects with) the x direction. The y direction is parallel to the circumferential direction around the central axis AX2. The y1 side is one side of the second direction and is opposite to the y2 side (the other side). The z direction is the third direction. The z direction is perpendicular to (intersects with) the x and y directions. The z direction is parallel to the axial direction of the central axis AX2. The z1 side is one side of the third direction and is opposite to the z2 side (the other side).

[0031] [First embodiment] First, the first embodiment will be described. FIG. 1 is a schematic diagram of a steering device of the first embodiment. FIG. 2 is a perspective view of a steering force assist mechanism of the first embodiment. FIG. 3 is a perspective view of a hook of the first embodiment. FIG. 4 is a side view of the steering force assist mechanism of the first embodiment. FIG. 5 is a schematic front view of the steering force assist mechanism of the first embodiment. FIG. 6A is an enlarged perspective view of the hook of the first embodiment. FIG. 6B is an enlarged perspective view of the hook of the first embodiment. FIG. 7 is a schematic view showing a worm shaft housing and a casting mold.

[0032] As shown in FIG. 1, the electric power steering device 80 includes a steering wheel 81, a steering shaft 82, a steering force assist mechanism 83, a universal joint 84, an intermediate shaft 85, a universal joint 86, a steering gear 88, an ECU 90, a vehicle speed sensor 95, an ignition switch 98, and a power supply device 99.

[0033] As shown in FIG. 1, the steering shaft 82 has an input shaft 82a and an output shaft 82b. The front end of the input shaft 82a is inserted inside the output shaft 82b. The steering force assist mechanism 83 includes a reduction gear 92, a motor 93, and a torque sensor 91. The steering force assist mechanism 83 will be described in detail later. The intermediate shaft 85 connects the universal joint 84 and the universal joint 86. One end of the intermediate shaft 85 is connected to the universal joint 84, and the other end is connected to the universal joint 86. One end of the pinion shaft 87 is connected to the universal joint 86, and the other end of the pinion shaft 87 is connected to the steering gear 88. The universal joint 84 and the universal joint 86 are, for example, Cardan joints. The rotation of the steering shaft 82 is transmitted to the pinion shaft 87 via the intermediate shaft 85. That is, the intermediate shaft 85 rotates together with the steering shaft 82.

[0034] As shown in Fig. 1, the steering gear 88 includes a pinion 88a and a rack 88b. The pinion 88a is connected to a pinion shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into linear motion by the rack 88b. The rack 88b is connected to a tie rod 89. The angle of the wheels changes as the rack 88b moves.

[0035] As shown in Fig. 1, the electric power steering device 80 includes an ECU (Electronic Control Unit) 90, a torque sensor 91, and a vehicle speed sensor 95. The motor 93, the torque sensor 91, and the vehicle speed sensor 95 are electrically connected to the ECU 90. The torque sensor 91 outputs the steering torque transmitted to the input shaft 82a to the ECU 90 through CAN (Controller Area Network) communication. The vehicle speed sensor 95 detects the traveling speed (vehicle speed) of the vehicle body on which the electric power steering device 80 is mounted. The vehicle speed sensor 95 is provided on the vehicle body, and outputs the vehicle speed to the ECU 90 through CAN communication.

[0036] As shown in FIG. 1, the ECU 90 controls the operation of the motor 93. The ECU 90 acquires signals from each of a torque sensor 91 and a vehicle speed sensor 95. When an ignition switch 98 is on, the ECU 90 is supplied with power from a power supply device 99 (e.g., an on-board battery). The ECU 90 calculates an auxiliary steering command value based on the steering torque and the vehicle speed. The ECU 90 adjusts the value of power supplied to the motor 93 based on the auxiliary steering command value. The ECU 90 acquires information on the induced voltage of the motor 93 or information output from a resolver or the like provided in the motor 93. The force required to operate the steering wheel 81 is reduced by the ECU 90 controlling the motor 93.

[0037] As shown in FIG. 2 and FIG. 4, the steering force assist mechanism 83 includes a reduction gear 92 and a motor 93. The reduction gear 92 is, for example, a worm reduction gear. The reduction gear 92 has a worm shaft 922, a worm wheel 921, and a reduction gear housing 100. The worm shaft 922 meshes with the worm wheel 921. The worm shaft 922 is attached to an output shaft 93d of the motor 93. The worm shaft 922 rotates in a direction around the central axis AX1. The worm wheel 921 rotates in a direction around the central axis AX2. The worm wheel 921 is perpendicular to the worm shaft 922. That is, the central axis AX2 is perpendicular to the central axis AX1. The reduction gear housing 100 is a casting formed using a casting mold 6 (see FIG. 7). The reduction gear housing 100 includes a worm shaft housing 2 and a worm wheel housing 3. The worm shaft housing 2 accommodates a worm shaft 922. The worm wheel housing 3 accommodates a worm wheel 921. The worm wheel housing 3 has a vehicle body mounting portion 34, and the vehicle body mounting portion 34 is attached to a vehicle body member (not shown).

[0038] As shown in FIG. 2, a motor 93 is attached to the worm shaft housing 2. The motor attachment flange 21 of the worm shaft housing 2 and the flange 93b of the motor 93 are fastened to each other via a bolt BL. Also, as shown in FIG. 2, the torque sensor 91 described above is accommodated inside the worm wheel housing 3. The motor 93 is provided with a protruding portion 910 that protrudes to the side. A connector CN that is electrically connected to the torque sensor 91 is provided at the lower portion of the worm wheel housing 3. One end of a sensor harness (harness) 911 is connected to the connector CN, and the other end is inserted into the protruding portion 910. The position of the sensor harness 911 is regulated by a hook 4 on the outer surface of the worm shaft housing 2. As shown in FIG. 3, the hook 4 is provided on the outer surface 2a of the worm shaft housing 2 included in the reducer housing 100, and protrudes toward the X1 side (one side in the first direction). A plurality of hooks 4 are provided to regulate the position of the sensor harness 911. Specifically, as shown in Fig. 2, the sensor harness 911 extends from the protrusion 910 along the axial direction on the outer surface 2a of the worm shaft housing 2. At this time, by hanging the sensor harness 911 across three hooks 4, tension is generated in the sensor harness 911 by the hooks 4. The position of the sensor harness 911 relative to the hooks 4 is restricted by this tension. In other words, without the hooks 4, the position of the sensor harness 911 would not be restricted, and the position of the sensor harness 911 would move left and right when an external force is applied to the sensor harness 911. The hooks will be described in detail below.

[0039] As shown in Fig. 3, the hook 4 according to the first embodiment is a key hook and includes a first key hook 41, a second key hook 42, and a third key hook 43. The first key hook 41, the second key hook 42, and the third key hook 43 are arranged in this order from the Y1 side to the Y2 side. That is, the first key hook 41, the second key hook 42, and the third key hook 43 are arranged along the Y direction (second direction). As shown in Fig. 5, the parting line PL1 extends in the Y direction. In this way, the multiple hooks 4 are arranged along the parting line PL extending in the Y direction.

[0040] With reference to FIG. 6A and FIG. 6B, the shape of the key hook will be described using the first key hook 41 as an example. As shown in FIG. 6A and FIG. 6B, the first key hook 41 has a base 4a and a position restricting portion 4b. The base 4a protrudes from the outer surface 2a of the worm shaft housing 2 to the X1 side. The position restricting portion 4b is fixed to the tip of the base 4a. The position restricting portion 4b is provided with a U-shaped notch 4c when viewed from the Y direction. The notch 4c has an opening 4e. The sensor harness 911 can be inserted from the opening 4e and restricted in position by the notch 4c. As shown in FIG. 3, the opening 4e of the notch 4c in the first key hook 41 faces the Z1 side. The opening 4e of the notch 4c in the second key hook 42 faces the Z2 side. The opening 4e of the notch 4c in the third key hook 43 faces the Z1 side. In the first embodiment, the first key hook 41, the second key hook 42, and the third key hook 43 all have the same height in the X direction.

[0041] As shown in FIG. 5, the first key hook 41, the second key hook 42, and the third key hook 43 are disposed along the parting line PL1. The parting line PL1 is non-linear when viewed from the X direction. Specifically, as shown in FIG. 5, the parting line PL1 is located on the Z2 side of the first key hook 41, on the Z1 side of the second key hook 42, and on the Z2 side of the third key hook 43. More specifically, as shown in FIG. 6A and FIG. 6B, the parting line PL1 is disposed so as to pass through the back surface 4d of the position restriction portion 4b of the first key hook 41, the second key hook 42, and the third key hook 43. In other words, when viewed from the X direction, the parting line PL1 does not overlap the notch 4c of the key hook.

[0042] 2, the position of the sensor harness 911 is restricted by the first key hook 41 having an opening 4e on the Z1 side, the position of the second key hook 42 having an opening 4e on the Z2 side, and the position of the third key hook 43 having an opening 4e on the Z1 side. In this manner, the orientations of the openings 4e of the key hooks are staggered in the Z direction from the first key hook 41 to the third key hook 43. Therefore, compared to an embodiment in which the openings 4e are oriented in the same direction in the Z direction from the first key hook 41 to the third key hook 43, the position of the sensor harness 911 is restricted in a curved state to the left and right.

[0043] As shown in FIG. 7, the casting mold 6 has a first mold 61 and a second mold 62. The first mold 61 is disposed adjacent to the second mold 62. An edge 611 of the first mold 61 and an edge 621 of the second mold 62 abut against each other. That is, the edges 611 and 621 in the abutting state are the parting line PL of the casting mold 6. As described above, the parting line PL1 according to the first embodiment is non-linear and passes through the back surface 4d of the position restriction portion 4b of the first key hook 41, the second key hook 42, and the third key hook 43. The first mold 61 moves in the first direction D1, and the second mold 62 moves in the second direction D2, thereby opening the casting mold 6.

[0044] As described above, the electric power steering device 80 includes the reducer housing 100 which includes either the worm shaft housing 2 or the worm wheel housing 3 and is made of a casting. A plurality of hooks 4 for regulating the position of the sensor harness 911 (harness) are provided on the outer surface 2a of the reducer housing 100. The plurality of hooks 4 are arranged along the parting line PL1 (PL) which extends in the Y direction.

[0045] As described above, the reducer housing of Patent Document 1 is provided with a resin clip, and a harness is attached to the clip. However, during vehicle assembly, the clip may be damaged when subjected to external force, such as when it is struck by another vehicle part, and therefore a highly rigid hook formed, for example, by casting is desired. However, when a reducer housing having a hook is formed by casting, the casting mold needs to be divided into many parts so that the mold does not get caught on the hook when it is opened.

[0046] Therefore, in this embodiment, a plurality of hooks 4 are provided and arranged along the parting line PL. As a result, for example, the casting mold 6 can be configured with two molds, a first mold 61 located on one side of the parting line PL, and a second mold 62 located on the other side of the parting line PL. Then, some of the plurality of hooks 4 can be molded by the first mold 61, and the remaining hooks 4 can be molded by the second mold 62. In this way, according to this embodiment, it is possible to mold the reducer housing 100 having the plurality of hooks 4 by casting using the casting mold 6 having fewer molds.

[0047] The hook 4 is a key hook. The key hook has a position restriction portion 4b in which a U-shaped cutout 4c is provided when viewed from the Y direction. The position of the sensor harness 911 inserted from an opening 4e of the cutout 4c is restricted by the cutout 4c. The opening 4e of the cutout 4c in the first key hook 41 faces the Z1 side (one side in the third direction). The opening 4e of the cutout 4c in the second key hook 42 faces the Z2 side (the other side in the third direction). The opening 4e of the cutout 4c in the third key hook 43 faces the Z1 side.

[0048] In a configuration in which the openings 4e are arranged in the same direction in the Z direction from the first key hook 41 to the third key hook 43, tension is unlikely to be generated in the sensor harness 911, and the sensor harness 911 may come loose from the direction in which the openings 4e are facing. However, in this embodiment, the openings 4e of the key hooks are arranged so that their orientations are staggered in the Z direction from the first key hook 41 to the third key hook 43, causing the sensor harness 911 to bend in a substantially S-shape and generating tension. Therefore, in this embodiment, the sensor harness 911 is less likely to come loose from multiple key hooks.

[0049] When viewed from the X direction, the parting line PL1 (PL) is located on the Z2 side of the first key hook 41, on the Z1 side of the second key hook 42, and on the Z2 side of the third key hook 43.

[0050] Since the sensor harness 911 is inserted into the cutout 4c and its position is restricted, if burrs or the like occur on the periphery of the cutout 4c, there is a possibility that the sensor harness 911 will be damaged. However, in this embodiment, since the parting line PL1 does not overlap with the cutout 4c when viewed from the X direction, the occurrence of burrs or the like on the periphery of the cutout 4c is suppressed.

[0051] [Modification 1 of the first embodiment] Next, a first modified example of the first embodiment will be described. Fig. 8 is a side view of a steering force assist mechanism according to the first modified example of the first embodiment. Fig. 9 is a perspective view of a hook according to the first modified example of the first embodiment.

[0052] In the steering force assist mechanism 83A according to the first modification of the first embodiment, the heights of the three key hooks 4A are different. As shown in FIG. 8 and FIG. 9, the height of the first key hook 41A along the X direction is defined as the first height H1. The height of the second key hook 42A along the X direction is defined as the second height H2. The height of the third key hook 43A along the X direction is defined as the third height H3. The first height H1 is the same as the third height H3. The first height H1 and the third height H3 are lower than the second height H2. However, in the present invention, the first height H1 and the third height H3 may be higher than the second height H2. In addition, in the first modification, the Y direction distance between the first key hook 41A and the second key hook 42A is the same as the Y direction distance between the second key hook 42A and the third key hook 43A.

[0053] As described above, the first height H1 of the first key hook 41A is different from the second height H2 of the second key hook 42A and is the same as the third height H3 of the third key hook 43A.

[0054] Therefore, when viewed from the Z direction, the sensor harness 911, whose position is restricted by the first key hook 41A, the second key hook 42A, and the third key hook 43A, has a gentle U-shape. In contrast, when the first height H1, the second height H2, and the third height H3 are all the same, the sensor harness 911 has a straight line when viewed from the Z direction. Therefore, according to this embodiment, the sensor harness 911 is bent more by the first key hook 41A, the second key hook 42A, and the third key hook 43A, and the tension becomes greater, and the position restriction force of the sensor harness 911 by the key hook 4A becomes stronger.

[0055] [Modification 2 of the First Embodiment] Next, a description will be given of Modification 2 of the first embodiment. Fig. 10 is a front view of the steering force assist mechanism according to Modification 2 of the first embodiment.

[0056] In the second modification of the first embodiment, the Y-direction distances of the three key hooks 4B are different. As shown in FIG. 10, the distance in the Y direction between the first key hook 41B and the second key hook 42B is a first distance L1. The distance in the Y direction between the second key hook 42B and the third key hook 43B is a second distance L2. The first distance L1 is greater than the second distance L2. However, the present invention also includes a case where the first distance L1 is less than the second distance L2. In the second modification, the heights in the X direction of the first key hook 41B, the second key hook 42B, and the third key hook 43B are the same.

[0057] As described above, in the steering force assist mechanism 83B, the first distance L1 in the Y direction between the first key hook 41B and the second key hook 42B is different from the second distance L2 in the Y direction between the second key hook 42B and the third key hook 43B.

[0058] Therefore, for example, when the second distance L2 is smaller than the first distance L1, the portion of the sensor harness 911 located between the second key hook 42B and the third key hook 43B will have a greater degree of bending and greater tension when viewed from the X direction than the portion of the sensor harness 911 located between the first key hook 41B and the second key hook 42B.

[0059] Therefore, the force with which the key hook 4B restricts the position of the sensor harness 911 is stronger than in a configuration in which the first key hook 41B, the second key hook 42B and the third key hook 43B are arranged at equal intervals in the Y direction.

[0060] [Third Modification of the First Embodiment] Next, a third modification of the first embodiment will be described. Fig. 11 is a perspective view of a hook according to the third modification of the first embodiment.

[0061] In the third modification of the first embodiment, the heights of the three key hooks 4C are different and the Y-direction distances are different. As shown in FIG. 11, the first distance L1 between the first key hook 41C and the second key hook 42C in the Y direction is greater than the second distance L2 between the second key hook 42C and the third key hook 43C in the Y direction. However, the present invention also includes an embodiment in which the first distance L1 is smaller than the second distance L2. Furthermore, the first height H1 of the first key hook 41C and the third height H3 of the third key hook 43C are lower than the second height H2 of the second key hook 42C. However, the present invention may also be an embodiment in which the first height H1 and the third height H3 are higher than the second height H2. In this way, the third modification is a combination of the first and second modifications.

[0062] As explained above, the first distance L1 between the first key hook 41C and the second key hook 42C is different from the second distance L2 between the second key hook 42C and the third key hook 43C. As a result, the first distance L1 is different from the second distance L2, and the first height H1 is different from the second height H2 and is the same as the third height H3, so that the sensor harness 911, whose position is restricted by the key hook 4C, is bent to a greater extent and the tension therein is increased, and the force with which the key hook 4C restricts the position of the sensor harness 911 is further increased.

[0063] [Second embodiment] Next, a second embodiment will be described. Fig. 12 is a front view of the steering force assist mechanism of the second embodiment. Fig. 13 is a perspective view of the hook according to the second embodiment. Fig. 14 is a perspective view of the hook according to the second embodiment. In the first embodiment, the parting line PL1 is non-linear, but in the second embodiment, the parting line PL2 is linear.

[0064] As shown in FIG. 12, when viewed from the X direction, the parting line PL2 is a straight line extending in the Y direction. When viewed from the X direction, the first key hook 41D included in the key hook 4D according to the second embodiment is located on the Z1 side of the parting line PL2. The second key hook 42D is located on the Z2 side of the parting line PL2. The third key hook 43D is located on the Z1 side of the parting line PL2. Specifically, as shown in FIG. 13 and FIG. 14, the parting line PL2 is disposed so as to pass through the back surface 4d of the position restriction portion 4b of the first key hook 41D, the second key hook 42D, and the third key hook 43D. In other words, when viewed from the X direction, the parting line PL2 does not overlap the notch 4c of the key hook 4D.

[0065] As described above, in the steering force assist mechanism 83D, the parting line PL2 is linear when viewed from the X direction. This allows the mating portion of the casting mold 6 to have a flat surface. That is, the edge 611 of the first mold 61 and the edge 621 of the second mold 62 are linear when viewed from the X direction, making it easier to manufacture the casting mold 6. In addition, since the mating portion of the casting mold 6 has a flat surface, there is also the advantage that the mating portion of the casting mold 6 is more tightly sealed.

[0066] [Third embodiment] Next, a third embodiment will be described. Fig. 15 is a perspective view of the steering force assist mechanism of the third embodiment. Fig. 16 is a perspective view of the hook of the third embodiment. Fig. 17 is a front view of the steering force assist mechanism of the third embodiment. Fig. 18 is a perspective view of the hook of the third embodiment. Fig. 19 is a perspective view of the hook of the third embodiment. In the first and second embodiments, a key hook has been described as an example of the hook, but in the third embodiment, a pillar-shaped hook will be described.

[0067] As shown in FIG. 15 to FIG. 19, the columnar hook 4E protrudes from the outer surface 2a to the X1 side. The columnar hook 4E includes a base 4h, a small diameter portion 4f, and a large diameter portion 4g. The base 4h is provided on the outer surface 2a. The small diameter portion 4f is a cylindrical member provided on the X1 side of the base 4h. The large diameter portion 4g is provided on the X1 side of the small diameter portion 4f. The large diameter portion 4g is a cylindrical member having a larger diameter than the small diameter portion 4f. The position of the sensor harness 911 is restricted by the small diameter portion 4f. As shown in FIG. 17, the first columnar hook 41E, the second columnar hook 42E, and the third columnar hook 43E are linearly arranged along the Y direction as viewed from the X direction. The parting line PL3 is linear. The parting line PL3 passes through the center in the Z direction of the first pillar-shaped hook 41E, the second pillar-shaped hook 42E, and the third pillar-shaped hook 43E. In the third embodiment, the first pillar-shaped hook 41E, the second pillar-shaped hook 42E, and the third pillar-shaped hook 43E are disposed at equal intervals along the Y direction.

[0068] As described above, in the steering force assist mechanism 83E, the pillar-shaped hook 4E includes the cylindrical small diameter portion 4f and the large diameter portion 4g.

[0069] In this manner, since the position of the sensor harness 911 is restricted by the cylindrical small diameter portion 4f, the sensor harness 911 may abut on either the right side or the left side of the small diameter portion 4f, which facilitates the task of restricting the position of the sensor harness 911 with the columnar hook 4E.

[0070] In addition, when viewed from the X direction, the columnar hooks 4E are arranged in a straight line, and the parting line PL3 is also straight and passes through the center of the columnar hooks 4E in the Z direction. This makes it difficult for the first die 61 and the second die 62 to get caught on the columnar hooks 4E when the casting mold 6 is opened, making it easier to mold the reducer housing 100.

[0071] [Modification 1 of the third embodiment] Next, a first modified example of the third embodiment will be described. Fig. 20 is a front view of a steering force assist mechanism according to the first modified example of the third embodiment.

[0072] As shown in Fig. 20, a pillar-shaped hook 4F according to the first modified example of the third embodiment has a first pillar-shaped hook 41F, a second pillar-shaped hook 42F, and a third pillar-shaped hook 43F. A first distance L1 between the first pillar-shaped hook 41F and the second pillar-shaped hook 42F in the Y direction is greater than a second distance L2 between the second pillar-shaped hook 42F and the third pillar-shaped hook 43F in the Y direction. In the present invention, the first distance L1 may be smaller than the second distance L2.

[0073] As described above, the multiple pillar-shaped hooks 4F include the first pillar-shaped hook 41F, the second pillar-shaped hook 42F, and the third pillar-shaped hook 43F. The first distance L1 in the Y direction between the first pillar-shaped hook 41F and the second pillar-shaped hook 42F is different from the second distance L2 between the second pillar-shaped hook 42F and the third pillar-shaped hook 43F.

[0074] Therefore, in the steering force assist mechanism 83F of this embodiment, the degree of bending of the sensor harness 911 by the first pillar-shaped hook 41F, the second pillar-shaped hook 42F and the third pillar-shaped hook 43F increases, the tension increases, and the positional restriction force of the sensor harness 911 by the pillar-shaped hook 4F becomes stronger.

[0075] [Fourth embodiment] Next, a fourth embodiment will be described. Fig. 21 is a side view of the steering force assist mechanism of the fourth embodiment. Fig. 22 is a front view of the steering force assist mechanism of the fourth embodiment. Fig. 23 is a perspective view of the steering force assist mechanism of the fourth embodiment. Fig. 24 is a perspective view of the steering force assist mechanism of the fourth embodiment. Fig. 25 is a front view of the steering force assist mechanism of the fourth embodiment.

[0076] In the first to third embodiments, the hook is provided on the worm shaft housing 2. In the fourth embodiment, however, a key hook (hook) 4G is provided on the worm wheel housing 3, as shown in Figures 21 to 25.

[0077] Specifically, in the fourth embodiment, three key hooks 4G having the same shape as the key hooks according to the first embodiment are arranged along the parting line PL4. That is, the shape of the first key hook 41G is the same as the first key hook 41, the shape of the second key hook 42G is the same as the second key hook 42, and the shape of the third key hook 43G is the same as the third key hook 43. As shown in FIG. 22, the worm wheel housing 3 is provided with a protrusion 3a, and a torque sensor 91 is housed inside the protrusion 3a. A connector CN electrically connected to the torque sensor 91 is provided at the lower part of the protrusion 3a. One end of a sensor harness (harness) 912 is connected to the connector CN, and the other end is inserted into the end 2b of the worm shaft housing 2 on the motor side. In the present invention, the harness is not limited to the sensor harness, and may be a harness such as a power harness.

[0078] As shown in FIG. 23, the worm wheel housing 3 includes a main body 31 and a cover 32. The main body 31 has a side surface 31a and a circumferential surface 31b. As shown in FIG. 21, the side surface 31a is a disk member. The circumferential surface 31b extends from the outer periphery of the side surface 31a along the axial direction of the central axis AX2. As shown in FIG. 23, the circumferential surface 31b has a cylindrical shape extending along the circumferential direction around the central axis AX2. Therefore, the first key hook 41G, the second key hook 42, and the third key hook 43G protrude outward (x1 side) in the radial direction centered on the central axis AX2. The first key hook 41G, the second key hook 42G, and the third key hook 43G are provided on the circumferential surface 31b and are arranged at equal intervals along the circumferential direction (y direction). As shown in FIG. 25, the parting line PL4 is nonlinear along the circumferential direction of the peripheral surface portion 31b when viewed from the radial direction (x direction) of the worm wheel 921. The parting line PL4 is located on the z2 side of the first key hook 41G, on the z1 side of the second key hook 42G, and on the z2 side of the third key hook 43G. As shown in FIG. 24, the opening 4e of the notch 4c in the first key hook 41G faces the z1 side. The opening 4e of the notch 4c in the second key hook 42G faces the z2 side. The opening 4e of the notch 4c in the third key hook 43G faces the z1 side. As shown in FIG. 24, the cover 32 is fastened to the peripheral surface portion 31b via the bolt BL. The flange 33 is fastened to the cover 32 via the bolt BL.

[0079] As described above, in the steering force assist mechanism 83G, even in the aspect in which the key hook 4G is provided on the worm wheel housing 3, the same effect as that of the above-mentioned embodiment can be obtained. That is, for example, the casting mold 6 can be configured with two molds, the first mold 61 located on one side of the parting line PL4 and the second mold 62 located on the other side of the parting line PL4. Then, some of the multiple key hooks 4G can be molded by the first mold 61, and the remaining key hooks 4G can be molded by the second mold 62. In this way, according to this embodiment, it is possible to mold the reducer housing 100 having the key hook 4G by casting using the casting mold 6 having fewer molds.

[0080] In addition, the parting line PL4 is located on the z2 side of the first key hook 41G, on the z1 side of the second key hook 42G, and on the z2 side of the third key hook 43G. Therefore, when viewed from the x direction, the parting line PL4 does not overlap with the cutout 4c, which prevents burrs from occurring on the peripheral edge of the cutout 4c.

[0081] [Fifth embodiment] Next, a fifth embodiment will be described. Fig. 26 is a side view of the steering force assist mechanism of the fifth embodiment. Fig. 27 is a front view of the steering force assist mechanism of the fifth embodiment. Fig. 28 is a front view of the steering force assist mechanism of the fifth embodiment. Fig. 29 is a perspective view of the steering force assist mechanism of the fifth embodiment. Fig. 30 is a perspective view of the hook according to the fifth embodiment. Fig. 31 is a perspective view of the hook according to the fifth embodiment.

[0082] In the fifth embodiment, as shown in FIG. 26 to FIG. 31, three key hooks (hooks) 4H are attached separately to the cover 32 and the peripheral surface portion 31b. The three key hooks 4H are a first key hook 41H, a second key hook 42H, and a third key hook 43H. As shown in FIG. 27, the first key hook 41H and the third key hook 43H are provided on the peripheral surface portion 31b. The second key hook 42H is provided on the cover 32. The opening 4e of the first key hook 41H faces the z2 side. The opening 4e of the second key hook 42H faces the z1 side. The opening 4e of the third key hook 43H faces the z2 side. As shown in FIG. 28, the parting line PL5 is linear along the circumferential direction of the peripheral surface portion 31b when viewed from the radial direction of the worm wheel 921. The parting line PL5 is the mating surface between the main body 31 and the cover 32 of the worm wheel housing 3. The parting line PL5 is located on the z1 side of the first key hook 41H, the z2 side of the second key hook 42H, and the z1 side of the third key hook 43H.

[0083] As described above, in the steering force assist mechanism 83H, the three key hooks (hooks) 4H are attached separately to the cover 32 and the peripheral portion 31b, and the cover 32 and the peripheral portion 31b are butted together, and this configuration can also have the same effect as the previously described embodiment. [Explanation of symbols]

[0084] 2 Wormshaft housing 2a Exterior 2b end 21 Motor mounting flange 3 Worm wheel housing 3a Protrusion 31 Main body 31a Side part 31b Peripheral part 32 Cover 33 Flange 34 Vehicle body mounting part 4. Hook 4a base 4b Position regulation part 4c Cutout 4d back 4e aperture 4f Small diameter section 4g Large diameter part 4h base 41 No. 1 Key Hook 42 Second Key Hook 43 3rd Key Hook 4A Key Hook (Hook) 41A 1st Key Hook 42A Second Key Hook 43A 3rd Key Hook 4B Key hook (hook) 41B 1st Key Hook 42B 2nd key hook 43B 3rd key hook 4C Key hook (hook) 41C 1st Key Hook 42C 2nd key hook 43C 3rd key hook 4D Key Hook (Hook) 41D 1st Key Hook 42D 2nd key hook 43D 3rd key hook 4E Pillar Hook (Hook) 41E 1st column hook 42E 2nd column hook 43E 3rd column hook 4F Pillar Hook (Hook) 41F 1st column hook 42F 2nd column hook 43F 3rd column hook 4G Key Hook (Hook) 41G 1st key hook 42G 2nd key hook 43G 3rd key hook 4H Key Hook (Hook) 41H 1st key hook 42H 2nd key hook 43H 3rd key hook 6 Casting mold 61 Type 1 611 Edge 62 Type 2 621 En 80 Electric power steering device 81 Steering Wheel 82 Steering shaft 82a Input shaft 82b Output shaft 83 Steering force assist mechanism 83A Steering force assist mechanism 83B Steering force assist mechanism 83D Steering force assist mechanism 83E Steering force assist mechanism 83F Steering force assist mechanism 83G Steering force assist mechanism 83H Steering force assist mechanism 84 Universal joint 85 Intermediate shaft 86 Universal joint 87 Pinion shaft 88 Steering gear 88a Pinion 88b Rack 89 Tie rod 90 ECU 91 Torque Sensor 910 Protrusion 911 Sensor Harness (Harness) 912 Sensor Harness (Harness) 92 Reducer 921 Worm Wheel 922 Worm shaft 93 Motor 93b flange 93d Output shaft 95 Vehicle speed sensor 98 Ignition Switch 99 Power supply 100 Reducer housing AX1 center axis AX2 center axis BL Bolt CN Connector D1 1st direction D2 2nd direction H1 Height H2 Height L1 1st distance L2 2nd distance PL parting line PL1 parting line PL2 parting line PL3 parting line PL4 parting line PL5 parting line

Claims

1. The reduction gear housing is made of a casting and includes at least one of a worm shaft housing that houses a worm shaft attached to an output shaft of a motor and a worm wheel housing that houses a worm wheel that meshes with the worm shaft; A plurality of hooks are provided on an outer surface of the reduction gear housing, the hooks protruding from the outer surface and extending to one side in a first direction and regulating a position of the harness, The plurality of hooks are arranged along a parting line extending in a second direction intersecting the first direction. Electric power steering device.

2. The hook is A key hook including a position restricting portion having a U-shaped notch when viewed from the second direction, the position of the harness inserted through an opening of the notch being restricted by the position restricting portion, the plurality of key hooks include a first key hook, a second key hook, and a third key hook arranged in order from one side to the other side in the second direction, the opening of the notch in the first key hook faces one side of a third direction intersecting the first direction and the second direction; the opening of the notch in the second key hook faces the other side in the third direction, The opening of the notch in the third key hook faces one side in the third direction.

2. The electric power steering device according to claim 1.

3. When viewed from the first direction, the parting line is a key hook disposed on the other side of the first key hook in the third direction; a key hook disposed on one side of the second key hook in the third direction; a third key hook disposed on the other side of the third key hook in the third direction; 3. The electric power steering device according to claim 2.

4. The parting line is linear when viewed from the first direction.

4. The electric power steering device according to claim 3.

5. A first height of the first key hook from the outer surface along the first direction is different from a second height of the second key hook and is equal to a third height of the third key hook.

4. The electric power steering device according to claim 3.

6. a first distance between the first key hook and the second key hook in the second direction is different from a second distance between the second key hook and the third key hook in the second direction; The electric power steering device according to any one of claims 2 to 5.

7. The hook is a columnar hook protruding from the outer surface to one side in the first direction, the pillar-shaped hook includes a cylindrical small diameter portion and a cylindrical large diameter portion provided on one side of the small diameter portion in the first direction and having a diameter larger than that of the small diameter portion, The position of the harness is restricted by the small diameter portion.

2. The electric power steering device according to claim 1.

8. When a direction intersecting the first direction and the second direction is a third direction, When viewed from the first direction, The plurality of post-shaped hooks are arranged in a straight line extending in the second direction, The parting line is linear and passes through the center of the plurality of pillar-shaped hooks in the third direction.

8. An electric power steering device according to claim 7.

9. The plurality of post-shaped hooks include a first post-shaped hook, a second post-shaped hook, and a third post-shaped hook, which are arranged in order from one side to the other side in the second direction, a first distance between the first post-shaped hook and the second post-shaped hook in the second direction is different from a second distance between the second post-shaped hook and the third post-shaped hook in the second direction; 9. An electric power steering device according to claim 7 or 8.

Images