JP2022106212A - Steering device - Google Patents

Abstract

To improve sealability between a boot and a housing of a steering device.SOLUTION: An electric power steering device 100 includes: a rack shaft 30 for turning wheels; a gear case 70 serving as a housing that houses the rack shaft 30 and includes an opening portion 71 from which the rack shaft 30 protrudes; a boot 80 covering the opening portion 71 of the gear case 70; and a boot band 90 serving as an annular band portion that presses the boot 80 toward an outer circumferential surface 72 of the gear case 70 to fix the boot thereto. The gear case 70 includes a pressed portion 75 of the outer circumferential surface 72, which is pressed by the boot band 90 and annular protrusions 76, 77, 78 and 79 protruding from the pressed portion 75 in a radial direction of the opening portion 71.SELECTED DRAWING: Figure 3

Description

The present invention relates to a steering device.

In the steering device described in Patent Document 1, a cylindrical boot is attached to the gear case. The boot is fastened and fixed to the cylindrical portion of the gear case by the boot band.

Japanese Unexamined Patent Publication No. 2020-171105

In such a steering device, the boots are fastened to the cylindrical portion of the gear case by the boot band, so that foreign matter is prevented from entering the gear case through the gap between the gear case and the boots. However, if the outer peripheral surface of the cylindrical portion of the gear case to which the boot is tightened is flat in the axial cross section, the contact surface between the gear case and the boot becomes linear in the cross section, so that a high seal is formed between the gear case and the boot. You may not be able to get sex.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the sealing property between the housing of the steering device and the boots.

The present invention is a steering device, the rack shaft for steering a wheel, a housing having an opening for accommodating the rack shaft and protruding from the rack shaft, a boot covering the opening of the housing, and a boot housing. The housing is provided with an annular band portion that is pressed and fixed toward the outer peripheral surface of the outer peripheral surface, and the housing has an annular portion of the outer peripheral surface that is pressed by the band portion and an annular portion that protrudes from the pressed portion in the radial direction of the opening. It is characterized by having a protruding portion of.

The present invention is characterized in that the protruding portion has a smaller dimension than the pressed portion in the axial direction of the opening.

In these inventions, since the boot is pressed by the band portion toward the protruding portion of the housing, the load from the band portion is more likely to be applied to the boot at the protruding portion than at other portions of the pressed portion. Therefore, the contact surface pressure between the housing and the boot increases at the protruding portion. As a result, the protruding portion of the housing and the boot can be brought into close contact with each other.

In the present invention, the protruding portion has a wall portion extending perpendicularly to the axial direction from the pressed portion and a tapered portion extending from the pressed portion toward the wall portion, and the tapered portion is larger than the wall portion. It is characterized in that it is provided on the opening side of the housing.

In the present invention, since the tapered portion is provided on the opening side of the housing with respect to the wall portion, the attachment of the boot to the housing is not hindered by the protruding portion. Further, since the attached boot is locked to the wall portion, the boot is prevented from falling off from the housing.

The present invention has, as the protruding portion, a first protruding portion and a second protruding portion provided from the center of the pressed portion in the axial direction away from the first protruding portion, and the second protruding portion has a diameter. It is characterized in that the amount of protrusion in the direction is larger than that of the first protrusion.

In the present invention, the amount of radial protrusion of the second protrusion formed on the end side of the pressed portion is larger than that of the first protrusion on the center side of the pressed portion. Therefore, the contact surface pressure between the housing and the boot increases on the end side of the pressed portion. Here, the wall thickness of the boot tends to be thin on the end side of the pressed portion. Therefore, since the contact surface pressure between the housing and the boot increases at a place where the boot tends to be thin, the sealing property between the housing and the boot can be efficiently improved.

According to the present invention, it is possible to improve the sealing property between the housing of the steering device and the boots.

It is a block diagram of the electric power steering apparatus which concerns on this embodiment. It is an enlarged sectional view of a gear case and a boot. It is an enlarged sectional view of the fixed part of a gear case and a boot. FIG. 3 is an enlarged cross-sectional view corresponding to FIG. 3 of a fixed portion between the gear case and the boot according to the modified example.

The electric power steering device 100 as the steering device according to the embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the electric power steering device 100 serves as a steering shaft 20 that rotates by a steering torque input from the steering wheel 10 and a steering shaft that steers the wheel 1 as the steering shaft 20 rotates. A rack shaft 30 is provided.

The steering shaft 20 is a torsion bar that connects an input shaft 21 that rotates with a steering operation in which the driver operates the steering wheel 10, an output shaft 22 that displaces the rack shaft 30, and the input shaft 21 and the output shaft 22. 23 and.

The rack shaft 30 is a shaft-shaped member extending in the left-right direction of the vehicle, is connected to one wheel 1 via a first tie rod 41a and a first knuckle arm 42a, and is connected to a second tie rod 41b and a second knuckle arm. It is connected to the other wheel 1 via 42b.

The first and second tie rods 41a and 41b are swingably connected to the rack shaft 30 via first and second ball joints 43a and 43b as connecting portions provided at both ends of the rack shaft 30. To. The connecting portion for connecting the rack shaft 30 and the first and second tie rods 41a and 41b is not limited to the first and second ball joints 43a and 43b, and other types of universal joints may be used. good.

The output shaft 22 and the rack shaft 30 are connected to each other via a rack and pinion mechanism including a pinion gear 22a provided at the end of the output shaft 22 and a rack gear 30a provided on the rack shaft 30. The pinion gear 22a and the rack gear 30a are meshed with each other, and the torque of the output shaft 22 is converted into a load in the axial direction of the rack shaft 30 via the pinion gear 22a and the rack gear 30a and transmitted to the rack shaft 30. As a result, the rack shaft 30 is displaced in the axial direction by the transmitted torque, and the wheels 1 are steered via the first and second tie rods 41a and 41b.

Further, the electric power steering device 100 includes an electric motor 50 that is driven to assist the steering force in response to the steering operation, and a deceleration unit 52 that decelerates the rotation of the electric motor 50 and transmits it to the steering shaft 20. Be prepared.

The speed reduction unit 52 is a worm gear mechanism including a worm shaft 53 driven by an electric motor 50 and a worm wheel 54 provided on the output shaft 22. The worm shaft 53 and the worm wheel 54 mesh with each other, and the torque of the electric motor 50 is transmitted to the output shaft 22 via the worm shaft 53 and the worm wheel 54. The torque transmitted from the electric motor 50 to the output shaft 22 is further transmitted to the rack shaft 30 via the pinion gear 22a and the rack gear 30a.

Further, the electric power steering device 100 further includes a torque sensor 62 that detects the torque acting on the torsion bar 23, and a controller 60 that controls the drive of the electric motor 50 according to the detection value of the torque sensor 62.

The controller 60 includes a CPU (Central Processing Unit) that performs arithmetic processing, a ROM (Read-Only Memory) that stores a control program and the like executed by the CPU, and a RAM (random access memory) that stores the arithmetic results of the CPU. And consists of a microcomputer including. The controller 60 may be composed of a single microcomputer or may be composed of a plurality of microcomputers.

The torque sensor 62 detects the steering torque applied to the input shaft 21 as the driver operates the steering, and outputs a signal corresponding to the detected steering torque to the controller 60. The controller 60 calculates the torque output by the electric motor 50 based on the signal from the torque sensor 62, and controls the drive of the electric motor 50 so that the torque is generated.

As described above, in the electric power steering device 100 having the above configuration, the steering torque applied to the input shaft 21 is detected by the torque sensor 62, and the drive of the electric motor 50 is controlled by the controller 60 based on the detection result. It is possible to assist the driver's steering operation.

As shown in FIG. 2, the electric power steering device 100 includes a gear case 70 as a housing that accommodates the rack shaft 30 and has openings 71a and 71b from which the rack shaft 30 protrudes. The gear case 70 is made of a metal such as aluminum.

The electric power steering device 100 includes boots 80a and 80b that cover the openings 71a and 71b of the gear case 70, and boot bands 90a as an annular band portion that presses and fixes the boots 80a and 80b toward the outer peripheral surface 72 of the gear case 70. , 90b and. The boots 80a and 80b cover the rack shaft 30 protruding from the openings 71a and 71b of the gear case 70 and the first and second tie rods 41a and 41b (see FIG. 1), respectively, and the rack shaft 30 and the first and first boots 80a and 80b. (2) Protect the tie rods 41a and 41b from foreign matter. Further, the boot bands 90a and 90b are formed with predetermined lengths in the axial direction, and the boots 80a and 80b are fastened and fixed to the outer peripheral surface 72 of the gear case 70, respectively. As a result, the openings 71a and 71b are covered with the boots 80a and 80b, and foreign matter is prevented from entering the gear case 70 through the openings 71a and 71b.

Since the configurations of the openings 71a, 71b, the boots 80a, 80b, and the boot bands 90a, 90b are the same, the configurations of the left opening 71a, the boots 80a, and the boot band 90a in FIG. 2 will be described below. The description of the configuration of the vicinity of the opening 71b, the boot 80b, and the boot band 90b will be omitted. Further, in the following, the opening 71a is also simply referred to as “opening 71”, the boot 80a is simply referred to as “boot 80”, and the boot band 90a is simply referred to as “boot band 90”.

The gear case 70 has an accommodating hole 73 for accommodating the rack shaft 30, and a recess 74 formed on the outer peripheral surface 72 to which the boot band 90 is attached together with the boot 80. The accommodating hole 73 penetrates the gear case 70, and an opening 71 is formed at the end thereof. The rack shaft 30 penetrates the accommodating hole 73 and protrudes from the opening 71. The recess 74 is formed in an annular shape in the vicinity of the opening 71, and the axial length is formed longer than the axial length of the boot band 90. That is, on the outer peripheral surface 72 of the gear case 70, a part of the recess 74 is pressed inward in the radial direction by the boot band 90. In other words, the gear case 70 has a pressed portion 75 of the outer peripheral surface 72 that is pressed by the boot band 90. Specifically, the pressed portion 75 refers to a region of the recess 74 located inside the boot band 90 in the radial direction.

As shown in FIG. 3, the recess 74 is formed with an annular protrusion 76 that protrudes from the pressed portion 75 in the radial direction of the opening 71. In other words, the protrusion 76 is formed between both ends of the pressed portion 75 in the axial direction of the opening 71. In the present embodiment, two protrusions 76 having the same shape are formed in the vicinity of the center of the recess 74 with an axial interval.

The protrusion 76 extends from the bottom surface of the recess 74 of the gear case 70 toward the wall portion 76a extending perpendicular to the axial direction of the opening 71, and from the bottom surface of the recess 74 toward the wall portion 76a so as to be separated from the opening 71. It has a tapered portion 76b and a connecting portion 76c that connects the wall portion 76a and the tapered portion 76b. Specifically, the wall portion 76a protrudes from the pressed portion 75 of the outer peripheral surface 72 along the radial direction of the opening 71. The tapered portion 76b is formed so that the amount of radial protrusion of the opening 71 increases as it approaches the wall portion 76a. The connecting portion 76c is provided along the axial direction of the opening 71. That is, the protruding portion 76 is formed so that the cross section of the opening 71 along the axial direction is trapezoidal. The bottom surface of the recess 74 from which the wall portion 76a and the tapered portion 76b extend is a part of the outer peripheral surface 72.

The tapered portion 76b is provided on the opening 71 side of the gear case 70 with respect to the wall portion 76a. Specifically, the opening 71a and the opening 71b will be described. In the protruding portion 76 formed in the recess 74 in the vicinity of the opening 71a, the tapered portion 76b is provided on the opening 71a side of the wall portion 76a. Further, although not shown, in the protruding portion formed in the concave portion near the opening 71b, the tapered portion is provided on the opening 71b side with respect to the wall portion.

The boot 80 is, for example, a bellows-shaped tubular member made of rubber or resin. The boot 80 can be expanded and contracted in the axial direction of the rack shaft 30 so as to be able to follow the reciprocating motion of the rack shaft 30. The boot 80 has a main body portion 81 and an annular mounting portion 82 provided at the end of the main body portion 81 and attached to the gear case 70. The inner peripheral surface of the mounting portion 82 comes into contact with the bottom surface of the recess 74 of the gear case 70. At the end of the mounting portion 82 on the opposite side of the main body portion 81, a flange portion 83 protruding outward in the radial direction of the mounting portion 82 is formed. A storage space 84 in which the boot band 90 can be accommodated is formed on the outer peripheral surface of the mounting portion 82 by the boundary between the main body portion 81 and the mounting portion 82 and the flange portion 83. The accommodation space 84 is formed in a concave shape, and the axial length is formed longer than the axial length of the boot band 90 so that the boot band 90 can be accommodated. The boot 80 is attached to the gear case 70 from the opening 71 side so that the inner peripheral surface of the attachment portion 82 is accommodated in the recess 74, and then the boot band 90 is attached to the accommodation space 84. Then, it is tightened and fixed in the recess 74 of the gear case 70. The other end of the boot 80 is fixed to the first tie rod 41a.

In this way, when the boot 80 is tightened and fixed to the gear case 70 by the boot band 90, the boot 80 is pressed toward the protruding portion 76 of the gear case 70. Therefore, the load from the boot band 90 is more likely to act on the boot 80 at the protruding portion 76 than at the other portion of the pressed portion 75. Therefore, the contact surface pressure between the gear case 70 and the boot 80 is increased at the protruding portion 76, and the protruding portion 76 of the gear case 70 and the boot 80 can be brought into close contact with each other. In the present embodiment, the contact surface pressure between the gear case 70 and the boot 80 increases at the corner portion between the wall portion 76a and the connecting portion 76c, and the gear case 70 and the boot 80 come into close contact with each other. Therefore, the sealing property between the gear case 70 and the boot 80 can be improved.

When the gear case does not have a protruding portion, the gear case and the boot are in contact with each other on a cylindrical surface, and the contact surface between the gear case and the boot is linear in the axial cross section of the opening. In this configuration, the entry path of foreign matter that tries to enter the gear case through between the gear case and the boot is short. On the other hand, since the gear case 70 of the electric power steering device 100 in the present embodiment has the protruding portion 76, the intrusion route of foreign matter that tries to enter the gear case 70 through between the gear case 70 and the boots 80 becomes long. Therefore, the sealing property between the gear case 70 and the boot 80 can be improved.

Therefore, for example, even when the electric power steering device 100 receives muddy water or salt water in a quality test or the like, the sealing property between the gear case 70 and the boots 80 is high, so that the inside of the gear case 70 is contained. It is possible to suppress the progress of corrosion of the aluminum gear case 70 by invading muddy water or salt water.

Further, the protruding portion 76 is provided with a tapered portion 76b extending toward the wall portion 76a on the opening 71 side of the gear case 70 with respect to the wall portion 76a. Specifically, in the protrusion 76 formed in the recess 74 near the opening 71a, the tapered portion 76b is provided on the opening 71a side of the wall portion 76a, and the protrusion formed in the recess 74 near the opening 71b. In the portion 76, the tapered portion 76b is provided on the opening 71b side with respect to the wall portion 76a. Therefore, when the boot 80 is attached to the gear case 70 from the opening 71 side, the boot 80 can easily get over the protruding portion 76 by the tapered portion 76b, so that the attachment of the boot 80 to the gear case 70 is hindered by the protruding portion 76. Not done. Further, since the attached boot 80 is locked to the wall portion 76a, the boot 80 is prevented from falling off from the gear case 70.

According to the above embodiment, the following actions and effects are exhibited.

In the electric power steering device 100, since the boot 80 is pressed toward the protruding portion 76 of the gear case 70, the boot 80 receives a load from the boot band 90 at the protruding portion 76 more than other portions at the pressed portion 75. It becomes easier to work. Therefore, the contact surface pressure between the gear case 70 and the boot 80 is increased at the protruding portion 76, and the protruding portion 76 of the gear case 70 and the boot 80 can be brought into close contact with each other. In the present embodiment, the contact surface pressure between the gear case 70 and the boot 80 increases at the corner portion between the wall portion 76a and the connecting portion 76c, and the gear case 70 and the boot 80 come into close contact with each other. Therefore, the sealing property between the gear case 70 and the boot 80 can be improved.

Since the gear case 70 has the protruding portion 76, the entry path of the foreign matter that tries to enter the gear case 70 through between the gear case 70 and the boot 80 becomes long. Therefore, the sealing property between the gear case 70 and the boot 80 can be improved.

Since the protruding portion 76 has a tapered portion 76b extending toward the wall portion 76a provided on the opening side 55 of the gear case 70 with respect to the wall portion 76a, the boot 80 is attached to the gear case 70 from the opening 71 side. However, since the tapered portion 76b can easily get over the protruding portion 76, the attachment of the boot 80 to the gear case 70 is not hindered by the protruding portion 76. Further, since the attached boot 56 is locked to the wall portion 76a, the boot 80 is prevented from falling off from the gear case 70.

Next, a modification of the present embodiment will be described.

<Modification 1>
In the above embodiment, two projecting portions 76 having the same shape are provided near the center of the pressed portion 75 at intervals in the axial direction. However, for example, as shown in FIG. 4, three protrusions 77, 78, 79 having different shapes may be formed as the protrusions. Specifically, the electric power steering device 100 is provided as a protruding portion with a protruding portion 77 as a first protruding portion and a protrusion 71 away from the center of the pressed portion 75 in the axial direction of the opening 71. It may be configured to have a protrusion 78 and a protrusion 79 as the second protrusion. The protruding portion 77 is provided, for example, near the center of the pressed portion 75. The protrusion 78 is provided on the opening 71 side of the protrusion 77, and the protrusion 79 is formed on the side opposite to the protrusion 78 with respect to the protrusion 77. That is, the protrusions 78 and 79 are provided on the end side of the pressed portion 75 with respect to the protrusion 77 in the axial direction of the opening 71.

The protruding portion 77 has a wall portion 77a, a tapered portion 77b, and a connecting portion 77c, similarly to the protruding portion 76 in the above embodiment. The protrusion 78 is a wall portion 78a extending perpendicularly to the axial direction of the opening 71 from the pressed portion 75, and a tapered portion 78b extending away from the opening 71 from the pressed portion 75 toward the wall portion 78a. And, the wall portion 78a and the tapered portion 78b are continuous. The protruding portion 79 has a wall portion 79a and a tapered portion 79b, similarly to the protruding portion 78. The protrusion 78 and the protrusion 79 are formed so that the amount of protrusion of the opening 71 from the concave portion 74 in the radial direction is larger than that of the protrusion 77. Specifically, the wall portions 78a and 79a are formed so that the radial length of the opening portion 71 is longer than that of the wall portion 77a. Therefore, in the protrusions 78 and 79 provided on the end side of the pressed portion 75 with respect to the protrusion 77, the amount of protrusion in the radial direction of the opening 71 is larger, so that the load from the boot band 90 is larger than that of the protrusion 77. Becomes easier to work with. Therefore, the contact surface pressure between the gear case 70 and the boot 80 increases on the end side of the pressed portion 75.

Here, the inner peripheral surface of the mounting portion 82 of the boot 80 comes into contact with the bottom surface of the recess 74 of the gear case 70. Therefore, the boot 80 is thick on the central side of the recess 74 in the axial direction, and the boot 80 is thin on both ends of the recess 74 in the axial direction. In other words, the boot 80 tends to be thin on both ends of the pressed portion 75. In the place where the boot 80 is thin, the contact surface pressure between the gear case 70 and the boot 80 is lower than in the place where the boot 80 is thick, so that the sealing property between the gear case 70 and the boot 80 may be deteriorated. However, in this modification, the contact surface pressure between the gear case 70 and the boot 80 is high on the end side of the pressed portion 75 where the boot 80 tends to be thin, so that the sealing property between the gear case 70 and the boot 80 is efficient. Can be improved.

In addition, only one of the protrusions 78 and 79 may be formed. When four or more protrusions are formed, an opening between any of the protrusions and a protrusion provided from the center of the pressed portion 75 in the axial direction of the opening 71 away from the protrusion. It is desirable that the amount of protrusion in the radial direction of the portion 71 is compared, and the amount of protrusion of the latter is larger. Even with these configurations, the sealing property between the gear case 70 and the boot 80 can be efficiently improved as described above.

<Modification 2>
In the above embodiment, two protrusions 76 having the same shape are provided as the protrusions. However, the number of protrusions may be one or a plurality of three or more. When the number of protrusions is plurality, they may be provided at intervals in the axial direction. By adjusting the number of protrusions in this way, the number of places where the gear case 70 and the boot 80 are in close contact with each other and the intrusion route of foreign matter that tries to enter the gear case 70 through between the gear case 70 and the boot 80 The length can be adjusted in stages. Therefore, the sealing property between the gear case 70 and the boot 80 can be adjusted stepwise.

When the number of the protruding portions is one, it is preferable that the protruding portions have a dimension smaller than that of the pressed portion 75 in the axial direction of the opening portion 71. The dimension of the protruding portion means, for example, in the protruding portion 76, from the boundary between the pressed portion 75 and the tapered portion 76b to the boundary between the pressed portion 75 and the wall portion 76a. As a result, the contact surface pressure between the gear case 70 and the boot 80 is surely increased at the protruding portion, and the sealing property between the gear case 70 and the boot 80 can be surely improved. However, if the protrusion is configured such that the length of the opening 71 in the axial direction decreases as the distance from the pressed portion 75 in the radial direction increases, the protrusion is pressed in the axial direction of the opening 71. It may have the same dimensions as the portion 75.

<Modification 3>
In the above embodiment, as the projecting portion, a projecting portion 76 having a trapezoidal cross section along the axial direction of the opening portion 71 is provided. However, the shape of the protruding portion is not limited to the above. For example, the cross section of the protrusion along the axial direction of the opening 71 may be formed to be triangular, square, or semicircular. Further, when there are a plurality of protrusions, even if the protrusions having different cross sections along the axial direction of the opening 71 are mixed, the protrusions having different amounts of protrusions in the radial direction of the opening 71 are mixed. You may.

The configuration, operation, and effect of the embodiment of the present invention configured as described above will be collectively described.

The electric power steering device 100 as a steering device includes a rack shaft 30 for steering wheels 1, a gear case 70 as a housing having an opening 71 for accommodating the rack shaft 30 and a protrusion of the rack shaft 30, and a gear case 70. The boot 80 covers the opening 71 of the gear case 71, and the boot band 90 as an annular band portion for pressing and fixing the boot 80 toward the outer peripheral surface 72 of the gear case 70. It has a pressed portion 75 pressed by the band 90, and an annular protruding portion 76, 77, 78, 79 protruding from the pressed portion 75 in the radial direction of the opening 71.

Further, the protruding portions 76, 77, 78, 79 have dimensions smaller than those of the pressed portion 75 in the axial direction of the opening 71.

In these configurations, the boot 80 is pressed toward the protrusions 76, 77, 78, 79 of the gear case 70, so that the boot 80 has more protrusions 76, 77, 78 than the other parts of the pressed portion 75. , 79, the load from the boot band 90 is likely to act. Therefore, the contact surface pressure between the gear case 70 and the boot 80 increases at the protrusions 76, 77, 78, 79. As a result, the protruding portions 76, 77, 78, 79 of the gear case 70 and the boot 80 can be brought into close contact with each other.

Further, the protruding portions 76, 77, 78, 79 include wall portions 76a, 77a, 78a, 79a extending perpendicularly to the axial direction from the pressed portion 75, and wall portions 76a, 77a, 78a from the pressed portion 75. It has tapered portions 76b, 77b, 78b, 79b extending toward 79a, and the tapered portions 76b, 77b, 78b, 79b are closer to the opening 71 side of the gear case 70 than the wall portions 76a, 77a, 78a, 79a. It will be provided.

In this configuration, the tapered portions 76b, 77b, 78b, 79b extending toward the wall portions 76a, 77a, 78a, 79a are provided on the opening 71 side of the gear case 70 with respect to the wall portions 76a, 77a, 78a, 79a. The attachment of the boot 80 to the gear case 70 is not hindered by the protrusions 76, 77, 78, 79. Further, since the attached boot 80 is locked to the wall portions 76a, 77a, 78a, 79a, the boot 80 is prevented from falling off from the gear case 70.

Further, the electric power steering device 100 has a protrusion 77 as a first protrusion and a protrusion as a second protrusion provided from the center of the pressed portion 75 in the axial direction away from the protrusion 77 as the protrusion. The protrusions 78 and 79 have portions 78 and 79, and the protrusion amount in the radial direction of the protrusions 78 and 79 is larger than that of the protrusion 77.

In this configuration, the protrusions 78 and 79 formed on the end side of the pressed portion 75 have a larger radial protrusion than the protrusion 77 on the center side of the pressed portion 75. Since it is large, the contact surface pressure between the gear case 70 and the boot 80 increases on the end side of the pressed portion 75. Here, the wall thickness of the boot 80 tends to be thin on the end side of the pressed portion 75. Therefore, since the contact surface pressure between the gear case 70 and the boot 80 increases at the place where the boot 80 tends to be thin, the sealing property between the gear case 70 and the boot 80 can be efficiently improved.

Although the embodiments of the present invention have been described above, the above-described embodiments show only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above-described embodiments. do not have.

1 ... Wheel, 30 ... Rack shaft, 70 ... Gear case (housing), 71 ... Opening, 72 ... Outer surface, 75 ... Pressed part, 80 ... Boots, 90 ... Boot band (band part), 76 ... Protruding part, 77 ... Protruding part (first protruding part), 78 ... Protruding part (second protruding part), 79 ... Protruding part (Second protrusion), 100 ... Electric power steering device (steering device)

Claims (4)

It ’s a steering device.
A rack axle for steering wheels,
A housing that accommodates the rack shaft and has an opening from which the rack shaft protrudes.
Boots covering the opening of the housing and
An annular band portion for pressing and fixing the boot toward the outer peripheral surface of the housing is provided.
The housing is
Of the outer peripheral surface, the pressed portion pressed by the band portion and the pressed portion.
A steering device including an annular protrusion that protrudes from the pressed portion in the radial direction of the opening. The steering device according to claim 1.
A steering device characterized in that the protruding portion has a dimension smaller than that of the pressed portion in the axial direction of the opening. The steering device according to claim 1 or 2.
The protrusion is
A wall portion extending perpendicular to the axial direction from the pressed portion, and a wall portion.
It has a tapered portion extending from the pressed portion toward the wall portion, and has a tapered portion.
The steering device is characterized in that the tapered portion is provided on the opening side of the housing with respect to the wall portion. The steering device according to any one of claims 1 to 3.
The protruding portion includes a first protruding portion and a second protruding portion provided from the center of the pressed portion in the axial direction away from the first protruding portion.
The second protruding portion is a steering device characterized in that the amount of protrusion in the radial direction is larger than that of the first protruding portion.

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