JP5858842B2 - Steering device - Google Patents

Description

  The present invention relates to a steering device.

There is known a steering device provided with an impact absorbing function for absorbing an impact when a driver collides with a steering unit (secondary collision) at the time of a collision. Further, the steering device is provided with a seal member that prevents intrusion of dust such as dust into the housing constituting the steering device.
For example, in Patent Document 1, an annular dust seal that is in sliding contact with the outer peripheral surface of the large-diameter portion of the lower shaft is attached to the inner peripheral wall of the lower column. The inner circumferential wall of the lower column is not formed with an annular positioning portion composed of a protrusion, shoulder, stepped portion, or the like, or is in contact with the front side of the dust seal at a predetermined interval from the dust seal. A steering device is disclosed in which a positioning portion is provided, and the dust seal can move forward with the upper column and the like even after the upper column contacts the dust seal at the time of a secondary collision, and absorbs impact energy by the rigidity of the dust seal. ing.

Japanese Patent No. 4682041

By the way, a steering apparatus provided with an impact absorbing function is generally configured to absorb an impact when a shaft connected to a steering unit moves in an axial direction at the time of a collision. However, a seal member that prevents dust from entering the housing may be provided around the shaft. In such a case, when the shaft moves, the shaft collides with the seal member, and the range in which the shaft can move may be limited by the seal member.
The present invention has been made to solve such a technical problem, and an object of the present invention is to ensure a movable range of the shaft at the time of collision while preventing dust from entering the housing.

For this purpose, the present invention is a steering device for transmitting a steering torque in a steering part to a steered part, which is connected to the steering part, is rotatably supported, and has a cylindrical opening. A second shaft that is inserted into the opening of the first shaft and the first shaft and is relatively movable in the axial direction with respect to the first shaft, and is connected to be capable of transmitting torque to and from the first shaft. A shaft, a first housing that covers at least a portion of the first shaft, a first housing that is axially movable relative to the first housing inside the first housing, and that covers at least a portion of the second shaft. and second housings, provided between the outer and the inner periphery of the second housing of the first shaft, comprising a seal member for sealing between the first shaft and the second housing, the first shaft And a large-diameter portion having an outer diameter larger than that of the other portion of the first shaft and having an outer diameter larger than the inner diameter of the seal member, and the seal member moves when the first shaft receives a force in the axial direction. In this case, the steering device is configured to face the large diameter portion of the first shaft .

In addition, a bearing provided in the first housing and rotatably holding the first shaft may be further provided, and the first shaft may be rotatably held by the bearing and the seal member .

  According to the present invention, it is possible to secure a movable range of the shaft at the time of collision while preventing dust from entering the housing.

It is a figure showing a schematic structure of a steering device of this embodiment. It is a figure for demonstrating in detail the steering device of this embodiment. It is a figure for demonstrating the shock absorption function of a steering device. It is a figure for demonstrating the steering device as a comparative example. It is a figure for demonstrating the comparison with the steering device of this embodiment, and the steering device of a comparative example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating a schematic configuration of a steering apparatus 100 according to the present embodiment.
FIG. 2 is a diagram for explaining the steering device 100 of the present embodiment in detail.
The steering device 100 of this embodiment is a steering device for arbitrarily changing the traveling direction of a vehicle, and illustrates a configuration applied to an automobile. The steering device 100 of the present embodiment is a so-called column assist type electric power steering device.

  As shown in FIG. 1, the steering device 100 includes a wheel-like steering wheel (handle) 101 operated by a driver as an example of a steering unit, and a steering shaft 102 coupled to the steering wheel 101. Yes. The steering apparatus 100 includes an intermediate shaft 103 connected to the steering shaft 102 via a universal joint 103a, and a pinion shaft 104 connected to the intermediate shaft 103 via a universal joint 103b. The pinion shaft 104 rotates in conjunction with the rotation of the steering wheel 101.

  The steering device 100 includes a tie rod 105 connected to each of the left and right front wheels 250 as an example of a steered portion, and a rack shaft 106 connected to the tie rod 105. The rack teeth 106a formed on the rack shaft 106 and the pinion 104a formed on the pinion shaft 104 constitute a rack and pinion mechanism.

  Further, the steering device 100 includes an electric motor 110 that assists the rotation of the steering shaft 102 and a transmission mechanism 120 that transmits the driving force of the electric motor 110 to the steering shaft 102. The transmission mechanism 120 includes a worm gear 121 (see FIG. 2) coupled to the output shaft of the electric motor 110 and a worm wheel 122 (see FIG. 2) attached to the steering shaft 102. Is decelerated by the worm wheel 122 and transmitted to the steering shaft 102.

  Further, the steering device 100 receives a torque detection device 10S that detects the steering torque of the steering wheel 101, and an electronic control unit (ECU) that controls the operation of the electric motor 110 while receiving an output value of the torque detection device 10S. 130.

  The torque detection device 10S detects the steering torque applied to the steering wheel 101, the ECU 130 grasps the steering torque based on the output value from the torque detection device 10S, and drives the electric motor 110 based on the grasped steering torque. To control. Further, the ECU 130 uses a CPU that performs various arithmetic processes, a ROM that stores programs executed by the CPU, various data, and the like, and a RAM that is used as a working memory for the CPU, and the like, as a torque detection device 10S. The operation of the electric motor 110 is controlled based on the output value from.

  As shown in FIG. 2, the steering shaft 102 includes an upper shaft 140 connected to the steering wheel 101, an input shaft 141 connected to the upper shaft 140, a torsion bar 142 connected to the input shaft 141, and a torsion bar. 142 and an output shaft 143 connected to 142. The upper shaft 140, the input shaft 141, the torsion bar 142, and the output shaft 143 are coaxially connected in order from the steering wheel 101 side, and the output shaft 143 is connected to the intermediate shaft 103 via the universal joint 103a. (See FIG. 1).

  The upper shaft 140 as an example of the first shaft is a cylindrical member formed so that the outer diameter gradually changes from the upper end side on the steering wheel 101 side to the lower end side (see FIG. 1) on the intermediate shaft 103 side. is there. The upper shaft 140 is, in order from the upper end side, the first cylindrical portion 140a, the second cylindrical portion 140b (large diameter portion) having a larger outer diameter than the first cylindrical portion 140a, and the outer diameter from the first cylindrical portion 140a. And a third cylindrical portion 140c having a larger outer diameter than that of the second cylindrical portion 140b.

In this embodiment, the steering wheel 101 is connected to the first cylindrical portion 140a of the upper shaft 140.
A bearing 162a, which will be described later, is provided on the second cylindrical portion 140b of the upper shaft 140, and the upper shaft 140 is rotatably held by the outer jacket 162 through the bearing 162a. Further, a seal member 163 described later is provided on the third cylindrical portion 140 c of the upper shaft 140, and the upper shaft 140 is rotatably held by the inner jacket 161 via the seal member 163. As described above, the upper shaft 140 of the present embodiment is rotatably supported by the bearing 162a and the seal member 163 described later.

  The upper shaft 140 has a spline 140S formed on the inner peripheral surface thereof from the lower end portion to the center portion in the direction of the center line of the cylinder. The upper shaft 140 is provided so that the input shaft 141 is inserted inside and surrounds the input shaft 141. At this time, the spline 140S of the upper shaft 140 is attached so as to mesh with a spline 141S described later of the input shaft 141.

  The input shaft 141 as an example of the second shaft has a columnar portion on the upper shaft 140 side, and a spline 141S is formed on the outer peripheral surface thereof. The input shaft 141 is inserted inside the cylindrical upper shaft 140. The spline 141S of the input shaft 141 is spline-joined with the spline 140S formed on the inner peripheral surface of the upper shaft 140. Accordingly, the input shafts 141 are connected to each other so as to be relatively movable in the axial direction while rotating together with the upper shaft 140. Further, a concave portion 141a formed in a columnar shape in the axial direction from the end surface is formed at an end portion of the input shaft 141 on the torsion bar 142 side, and a spline is formed at the deepest portion of the concave portion 141a.

  The torsion bar 142 is a cylindrical member. A spline is formed on the outer peripheral surface of the upper end portion in the axial direction, and is splined with the spline formed in the concave portion 141 a of the input shaft 141. Further, the lower end of the torsion bar 142 in the axial direction is connected to the output shaft 143 by a connecting pin 144.

  The output shaft 143 is a cylindrical member formed so that the outer diameter gradually changes from the upper end side to the lower end side, and the outer diameters of the first cylindrical portion 143a and the first cylindrical portion 143a in order from the upper end side. A second cylindrical portion 143b having a larger outer diameter, a third cylindrical portion 143c having a larger outer diameter than the outer diameter of the second cylindrical portion 143b, and a fourth having a smaller outer diameter than the outer diameter of the third cylindrical portion 143c. A cylindrical portion 143d and a fifth cylindrical portion 143e having an outer diameter smaller than the outer diameter of the fourth cylindrical portion 143d are provided. A torsion bar 142 is inserted inside the output shaft 143.

  The first cylindrical portion 143a of the output shaft 143 is inserted into the concave portion 141a of the input shaft 141, and a detection target member to be detected by the torque detection device 10S is mounted on the outer peripheral surface of the second cylindrical portion 143b. A worm wheel 122 is mounted on the outer peripheral surface of the fourth cylindrical portion 143d, and the worm wheel 122 is restricted from moving upward in the axial direction by the third cylindrical portion 143c of the output shaft 143. A male screw is formed at the lower end in the axial direction of the fourth cylindrical portion 143d. The fifth cylindrical portion 143 e is connected to the lower end portion in the axial direction of the torsion bar 142 by a connecting pin 144.

The steering column 150 includes a column jacket 160 that accommodates a part of the steering shaft 102, a housing 170 that accommodates the transmission mechanism 120, and an adjustment mechanism 180 that is a mechanism for adjusting the position of the steering wheel 101. Yes.
The column jacket 160 is provided in the inner jacket 161 as an example of the second housing disposed inside, the outer jacket 162 as an example of the first housing disposed outside the inner jacket 161, and the inner jacket 161. And a sealing member 163 for sealing.

  The outer jacket 162 and the inner jacket 161 are members each having a cylindrical shape. The outer jacket 162 and the inner jacket 161 are arranged in this order from the upper side to the lower side in the axial direction. It is fitted so as to be relatively movable in the axial direction.

The inner jacket 161 is fitted inside a second housing 172 (described later) of the housing 170 on the end side, connected to the housing 170 and held by the housing 170. The inner jacket 161 covers at least a part of the input shaft 141.
Further, the inner jacket 161 has a seal holding portion 161H for holding the seal member 163 at an end portion on the side where the upper shaft 140 is provided. In the inner jacket 161, the seal member 163 is attached to the seal holding portion 161H.

  The outer jacket 162 is provided so as to cover at least a part of the upper shaft 140. The outer jacket 162 is fitted with a bearing 162a that rotatably holds the upper shaft 140. As shown in FIG. 2, the bearing 162 a is provided at the end of the outer jacket 162 on the steering wheel 101 (see FIG. 1) side. In the bearing 162 a, the outer ring is held on the inner periphery of the outer jacket 162, and the inner ring holds the upper shaft 140.

The seal member 163 is a ring-shaped member. In this embodiment, synthetic rubber such as nitrile rubber can be used as the material of the seal member 163.
The seal member 163 is attached to a seal holding part 161H formed on the inner periphery of the inner jacket 161. Further, the seal member 163 is provided on the outer periphery of the upper shaft 140. The seal member 163 seals between the outer peripheral surface of the upper shaft 140 and the inner peripheral surface of the inner jacket 161. Thereby, in this embodiment, intrusion of dust such as dust into the torque detection device 10S located below the inner jacket 161 is prevented.

  The outer diameter of the seal member 163 is slightly larger than the inner diameter of the seal holding portion 161H of the inner jacket 161. Further, the inner diameter of the seal member 163 is the same as the outer diameter of the third cylindrical portion 140c so that no gap is formed between the upper shaft 140 and the third cylindrical portion 140c, and the upper shaft 140 can be rotatably held. Set to

Further, the inner diameter of the seal member 163 of the present embodiment is set smaller than the outer diameter of the second cylindrical portion 140b of the upper shaft 140. That is, the second cylindrical portion 140 b of the upper shaft 140 is configured to be larger than the inner diameter of the seal member 163.
Here, the tightening margin of the seal member 163 with respect to the second cylindrical portion 140b of the upper shaft 140 is such that the upper shaft 140 moves relative to the seal member 163 and the seal member 163 and the second cylindrical portion 140b face each other as will be described later. In this state, the load received by the upper shaft 140 from the seal member 163 is set to be relatively large. In the present embodiment, the seal member 163 is opposed to the second cylindrical portion 140b of the upper shaft 140 rather than the load applied to the upper shaft 140 in a state of facing the third cylindrical portion 140c of the upper shaft 140. The tightening allowance is set so that the load applied to 140 increases.

  In the steering device 100 according to the present embodiment, in a normal state, the seal member 163 faces the third cylindrical portion 140c of the upper shaft 140 and rotatably holds the upper shaft 140, thereby deteriorating the steering feeling. The upper shaft 140 is supported without any problems. On the other hand, at the time of a collision described later, the seal member 163 applies a load to the upper shaft 140 when the second cylindrical portion 140b of the upper shaft 140 moves while facing the seal member 163.

  Note that the upper shaft 140 of the present embodiment is supported at two axial positions by a bearing 162a provided on one end side and a seal member 163 provided on the other end side. Thereby, in the steering apparatus 100 of the present embodiment, the occurrence of so-called swinging when the upper shaft 140 rotates is suppressed. In the steering device 100 according to the present embodiment, the steering feeling of the steering wheel 101 connected to the upper shaft 140 is improved by stably rotating the upper shaft 140.

The housing 170 includes a first housing 171 and a second housing 172.
The first housing 171 has a bearing 171a that rotatably supports the output shaft 143 on one end side in the axial direction (lower side in FIG. 2), and the other end side in the axial direction (FIG. 2). In FIG. 3, the upper side is an open member. An electric motor 110 is mounted on the first housing 171, and the first housing 171 houses a transmission mechanism 120 including a worm gear 121 mounted on the rotation shaft of the electric motor 110. The bearing 171a is restricted from moving toward one end in the axial direction by a fixing nut 145 screwed into a male screw formed in the fourth cylindrical portion 143d of the output shaft 143.

  The second housing 172 is a member that is open at both ends in the axial direction. The opening on one end side in the axial direction (the lower side in FIG. 2) is disposed so as to face the opening on the other end side in the axial direction of the first housing 171, for example, a bolt For example, the first housing 171 is fixed. The other end side in the second housing 172 in the axial direction (upper side in FIG. 2) is cylindrical. Then, the outer periphery of the inner jacket 161 is inserted into the inner peripheral surface of the opening of the second housing 172.

The adjustment mechanism 180 adjusts the position of the steering wheel 101 by changing the lengths of the column jacket 160 and the steering shaft 102. The adjustment mechanism 180 includes a column restraining portion 181 and a lever portion 182.
The column restraint portion 181 has a U-shaped cross section. The column restraining portion 181 is attached to the outer periphery of the outer jacket 162 of the column jacket 160.

  The lever part 182 is provided in the column restraint part 181. The lever portion 182 is a member for operating a tightening mechanism (not shown) that applies a force for tightening the column jacket 160 in a direction crossing the axial direction of the column jacket 160. Then, by operating the lever portion 182, the outer jacket 162 is tightened or loosened by the column restraint portion 181. For example, when the outer jacket 162 is tightened by the column restraint portion 181, the outer jacket 162 and the inner jacket 161 are fixed so as not to move. On the other hand, when the outer jacket 162 is loosened by the column restraint portion 181, the outer jacket 162 and the inner jacket 161 are in a state of being movable in the axial direction.

  For example, when adjusting the position of the steering wheel 101, the lever portion 182 of the adjustment mechanism 180 is operated to release the tightening of the outer jacket 162 by the column restraint portion 181. Then, the outer jacket 162 moves together with the upper shaft 140 by moving the lever portion 182 in the axial direction of the steering shaft 102. Then, the steering wheel 101 can be positioned at an arbitrary position within a predetermined range. Thereafter, the lever portion 182 is operated again and the outer jacket 162 is tightened by the column restraint portion 181, whereby the outer jacket 162 and the inner jacket 161 are fixed.

FIG. 3 is a diagram for explaining an impact absorbing function of the steering device.
The steering device 100 configured as described above has an impact absorbing function for absorbing an impact when a driver collides with the steering wheel 101 (secondary collision) at the time of a car collision. The shock absorbing function is realized by the upper shaft 140, the input shaft 141, the inner jacket 161, and the outer jacket 162 that constitute the steering shaft 102.

  As shown in FIG. 3, at the time of collision, the steering device 100 first moves between the inner jacket 161 and the outer jacket 162. In the present embodiment, the outer jacket 162 moves toward the housing 170 while moving relative to the inner jacket 161. Then, the outer jacket 162 stops until it moves to abut against the second housing 172 of the housing 170. As described above, the movement of the outer jacket 162 causes the upper shaft 140 held by the outer jacket 162 to move. Along with this, the steering wheel 101 connected to the upper shaft 140 moves, so that the impact on the driver is reduced.

Further, as shown in FIG. 3, during the collision, the steering device 100 moves between the upper shaft 140 and the input shaft 141. Specifically, the upper shaft 140 moves toward the housing 170 while moving with respect to the input shaft 141. Then, the upper shaft 140 stops after moving until it hits the end of the input shaft 141.
Thus, the steering wheel 101 connected to the upper shaft 140 is moved by the movement of the upper shaft 140 itself. This also reduces the impact on the driver in the steering device 100 of the present embodiment.

In the steering device 100 of the present embodiment, the upper shaft 140 is held by the seal member 163. When a collision occurs and the upper shaft 140 moves, the region of the upper shaft 140 that faces the seal member 163 changes from the third cylindrical portion 140c (see FIG. 2) to the second cylindrical portion 140b. Then, the upper shaft 140 moves while deforming the seal member 163 so as to expand the seal member 163. Therefore, collision energy is consumed when the upper shaft 140 moves with respect to the seal member 163.
As described above, the steering device 100 according to the present embodiment is configured such that the collision energy is absorbed and the impact applied to the driver is further alleviated by providing the seal member 163 on the outer periphery of the upper shaft 140 that moves at the time of the collision. doing.

Here, a steering device 900 of a comparative example will be described.
FIG. 4 is a view for explaining a steering device 900 of a comparative example.
Note that, in the steering device 900 of the comparative example, the same members as those in the present embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
In the steering device 900 of the comparative example, as shown in FIG. 4, a seal member is provided between the outer periphery of the input shaft 141 and the inner periphery of the inner jacket 161 and at the end of the input shaft 141 on the torque detection device 10S side. 963 is provided. The seal member 963 seals between the inner jacket 161 and the input shaft 141. Thus, in the steering device 900 of the comparative example, dust is prevented from entering the torque detection device 10S provided below the inner jacket 161.

  Here, also in the steering device 900 of the comparative example, an impact absorbing function is executed at the time of a car collision. At this time, the upper shaft 140 moves toward the input shaft 141 side. In the steering device 900 of the comparative example, the upper shaft 140 stops after moving until it hits the seal member 963.

FIG. 5 is a diagram for explaining a comparison between the steering device 100 of the present embodiment and the steering device 900 of the comparative example.
5A is an enlarged view of the Va portion of the steering device 100 of the present embodiment shown in FIG. 2, and FIG. 5B is an enlarged view of the Vb portion of the steering device 900 of the comparative example shown in FIG. It is.
As shown in FIG. 5A, in the steering device 100 of the present embodiment, the end of the upper shaft 140 is in contact with the end of the input shaft 141 after movement. Therefore, the amount of movement of the upper shaft 140 is equal to the end portion FA of the upper shaft 140 after movement located at the end of the input shaft 141 from the end portion FB (solid line) of the upper shaft 140 before movement shown in FIG. Distance L1 to (broken line).

  On the other hand, as shown in FIG. 5B, in the steering device 900 of the comparative example, the end of the upper shaft 140 is in a state of being in contact with the seal member 963 after the movement. Accordingly, the movement amount of the upper shaft 140 is changed from the end portion FB (solid line) of the upper shaft 140 before movement shown in FIG. 5B to the end portion FA (broken line) of the upper shaft 140 after movement located on the seal member 163. ) To the distance L2. The distance L2 of the moving amount of the steering device 900 of the comparative example is shorter than the distance L1 of the moving amount of the steering device 100 of the present embodiment by the thickness of the seal member 963.

  On the other hand, in the steering device 100 of the present embodiment, the seal member 163 is provided on the outer periphery of the upper shaft 140. Thereby, when the upper shaft 140 moves, the movement of the upper shaft 140 is not hindered by the seal member 163. That is, in the steering apparatus 100 of the present embodiment, the upper shaft 140 and the seal member 163 are attached to the upper shaft 140 provided outside the input shaft 141 instead of the input shaft 141 provided inside. It is configured not to collide. Therefore, the movable range of the upper shaft 140 can be expanded as much as possible.

  As described above, the steering device 100 according to the present embodiment has a steering wheel 101 connected to the upper shaft 140 as compared with the case where the seal member 963 is attached to the outer periphery of the input shaft 141 as in the steering device 900 of the comparative example, for example. It is possible to increase the movable distance. And since the moving amount | distance of the steering wheel 101 at the time of a collision becomes long, the impact concerning a driver | operator can be relieve | moderated more. Further, since the seal member 163 is provided between the upper shaft 140 and the inner jacket 161, it is possible to prevent dust from entering the inside of the housing 170.

DESCRIPTION OF SYMBOLS 100 ... Steering device 101 ... Steering wheel 102 ... Steering shaft 140 ... Upper shaft 141 ... Input shaft 160 ... Column jacket 161 ... Inner jacket 162 ... Outer jacket 163 ... Seal member

Claims (2)

A steering device for transmitting a steering torque in a steering part to a steered part,
A first shaft coupled to the steering portion and rotatably supported, and having a cylindrical opening;
The second shaft is inserted into the opening of the first shaft and is provided so as to be relatively movable in the axial direction with respect to the first shaft, and is coupled so as to be able to transmit torque to and from the first shaft. A shaft,
A first housing covering at least a portion of the first shaft;
A second housing provided inside the first housing so as to be relatively movable in the axial direction with respect to the first housing, and covering at least a part of the second shaft;
A seal member provided between an outer periphery of the first shaft and an inner periphery of the second housing and sealing between the first shaft and the second housing ;
The first shaft includes a large-diameter portion having an outer diameter larger than other portions of the first shaft and having an outer diameter larger than the inner diameter of the seal member;
The steering device according to claim 1, wherein the seal member faces the large-diameter portion of the first shaft when the first shaft is moved by receiving an axial force . A bearing provided on the first housing for rotatably holding the first shaft;
The steering apparatus according to claim 1, wherein the first shaft is rotatably held by the bearing and the seal member.

Images