Steering apparatus for vehicle

Abstract

To provide a steering device of a vehicle capable of regulating the steering of a wheel while suppressing a load to each mechanism connecting a steering shaft to the wheel at low cost, and easily adjusting the maximum steering angle.SOLUTION: A steering device for a vehicle includes a steering shaft configured to transmit a rotational operation to a steering wheel, a steering gear box including an input shaft coupled to the steering shaft and configured to convert the rotational operation of the steering wheel into an operation for steering wheels, a reduction gear provided on the steering shaft and the input shaft of the steering gear box and configured to convert the rotational operation of the steering wheel into a rotational operation decelerated relative to the rotational operation of the steering wheel, a rotating body configured to perform the rotational operation decelerated relative to the rotational operation of the steering wheel via the reduction gear, and a restriction portion configured to come into contact with a part of the rotating body to restrict rotation of the rotating body, the restriction portion being configured to adjust a position where the rotation is restricted.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a steering device for a vehicle. [Background technology]

[0002] Power steering is widely known as a vehicle steering device for assisting a driver's steering operation. Power steering amplifies the rotational force of the steering wheel using a hydraulic pump, an electric motor, or the like. Furthermore, the maximum steering angle (hereinafter referred to as the maximum steering angle) that is the turning angle of the vehicle's wheels as a result of the driver's steering operation is predetermined, and it is necessary to restrict the maximum steering angle so that it does not exceed this predetermined angle.

[0003] For example, Patent Document 1 discloses a vehicle in which a knuckle stopper bolt is provided on the inner surface of a knuckle that supports a wheel and changes the steering angle of the wheel, and the steering angle is regulated by the knuckle stopper bolt abutting against a stopper provided on the axle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 5-92055 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the steering angle is restricted by a knuckle stopper bolt as in Patent Document 1, the rotational force amplified by the power steering places a load on each mechanism connecting the pitman arm to the wheels, such as the steering linkage.

[0006] In the technology of Patent Document 1, a pressure sensor is provided in the stopper, and when the contact pressure detected by the pressure sensor increases, the power steering boost function is reduced, but this configuration requires the provision of a pressure sensor and power steering control, which poses problems such as increased cost and complicated control.In addition, adjusting the left and right maximum steering angles requires adjusting the protruding length of each knuckle stopper bolt, which is time-consuming.

[0007] Therefore, an object of the present disclosure is to provide a vehicle steering device that is low-cost, can regulate the steering of the wheels while reducing the load on each mechanism connecting the steering shaft to the wheels, and can easily adjust the maximum steering angle. [Means for solving the problem]

[0008] The present disclosure has been made to solve at least some of the above-mentioned problems, and can be realized in the following aspects or application examples.

[0009] The steering device of the vehicle according to this application example is characterized by comprising: a steering shaft that transmits a rotational motion relative to a steering wheel; a steering gearbox having an input shaft connected to the steering shaft and converting the rotational motion of the steering wheel into a motion for steering wheels; reduction gears that are provided on the steering shaft and the input shaft of the steering gearbox and convert the rotational motion into a rotational motion slower than that of the steering wheel; a rotating body that rotates at a speed slower than that of the steering wheel via the reduction gear; and a regulating unit that comes into contact with a part of the rotating body to regulate the rotation of the rotating body and whose position for regulating the rotation is adjustable.

[0010] In this way, the steering of the wheels is restricted by restricting the rotation of the input shaft of the steering gearbox through the rotation of the steering wheel. In other words, because the steering angle is restricted at a stage before power steering is boosted, the load on the restricting unit is small, and it is possible to prevent unnecessary load from being applied to the mechanisms connecting the steering shaft to the wheels. Furthermore, because the restricting unit is provided on the input shaft of the steering gearbox, it is easy to adjust the maximum steering angles to the left and right. This makes it possible to restrict the steering of the wheels while reducing the load on the mechanisms connecting the steering shaft to the wheels, without the need for sensors or the like, and at low cost, and also makes it easy to adjust the maximum steering angle. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an overall side view of a vehicle equipped with a steering device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic side view showing the mechanisms connecting the steering shaft to the wheels in the embodiment. [Figure 3] FIG. 3 is an enlarged view of a main part of the steering gear box of FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the contents described below, and can be implemented with any modifications within the scope of the gist thereof. Furthermore, the drawings used to describe the embodiments are all schematic representations of components, and may be partially emphasized, enlarged, reduced, or omitted to facilitate understanding, and may not accurately represent the scale, shape, etc. of the components.

[0013] Fig. 1 is an overall side view of a vehicle 1 equipped with a steering device 2 according to this embodiment. Fig. 2 is a side view showing the mechanisms connecting the steering shaft to the wheels. Note that, hereinafter, "height direction" refers to the up-down direction of the vehicle, "vehicle width direction" refers to the left-right direction of the vehicle, and "front-rear direction" refers to the vehicle length direction.

[0014] The vehicle 1 according to this embodiment is a cab-over type vehicle in which the driver's seat is provided in front of the front wheels (wheels), and is, for example, a cargo vehicle such as a truck. The vehicle 1 includes a chassis frame 10, a cab 20, a cargo box 30, and a plurality of wheels 40.

[0015] The chassis frame 10 is a pair of left and right frames extending in the longitudinal direction of the vehicle 1 (only the frame on the right side of the vehicle is shown). As shown in Figure 1, a cab 20 is provided in front of the chassis frame 10, and a cargo box 30 is provided behind the cab 20. In addition, the chassis frame 10 is provided with drive devices such as an engine and a transmission, and various heavy objects.

[0016] A driver's seat 21 is provided in the cab 20. A steering wheel 22 for the driver to operate the steering wheel is provided in front of the driver's seat 21, and a steering shaft 23 extends from the steering wheel 22 to under the floor of the driver's seat 21. The steering wheel 22 and the steering shaft 23 will be described in the steering device 2 described below.

[0017] The vehicle 1 of this embodiment has four wheels 40: left and right front wheels 40a and left and right rear wheels 40b, and the left and right front wheels 40a are steered wheels that change the direction of travel of the vehicle 1. The wheels 40 are suspended from the chassis frame 10 via axles and support the weight of the vehicle 1.

[0018] Next, we will explain the steering device 2 of the vehicle 1. As shown in Fig. 2, the steering device 2 includes a steering wheel 22, a steering shaft 23, a steering column 23a, a steering gear box 24, a pitman arm 25, a drag link 26, a knuckle arm 27, and a tie rod 28.

[0019] The steering wheel 22 has a hub 22b connected to the inside of a substantially circular rim 22a via spokes, and a steering shaft 23 is connected to the hub 22b.

[0020] The steering shaft 23 connects the steering wheel 22 and the steering gear box 24, and rotates around its axis in accordance with the rotation of the steering wheel 22, thereby transmitting the rotational movement of the steering wheel 22 to the steering gear box 24.

[0021] The steering column 23a surrounds the steering shaft 23 and supports the steering shaft 23. Although not shown, the steering column 23a is also provided with function levers (switches) for blinkers, wipers, etc.

[0022] The steering gearbox 24 is attached to the chassis frame 10 of the vehicle 1. Specifically, as shown in FIG. 2 , the steering gearbox 24 is attached to the outer side of the chassis frame 10 on the right side of the vehicle in the vehicle width direction using connectors such as bolts and nuts. The steering gearbox 24 has a function of converting the rotational movement of the steering wheel 22 into an operation for steering the front wheels 40a. Although not shown, various gears are built into the steering gearbox 24, and a hydraulic mechanism that hydraulically amplifies and outputs rotational torque is also provided. In other words, the steering gearbox 24 has a power steering function that assists steering operation. Note that, in the case where the vehicle 1 is a truck as in this embodiment, a relatively large rotational torque is required to steer the vehicle 1, so hydraulic power steering is preferable, but electric power steering using an electric motor may also be adopted. Furthermore, the power steering does not need to be provided in the steering gearbox and may be provided in another location.

[0023] The steering gear box 24 has an input shaft 241 and an output shaft 242. The input shaft 241 is connected to the steering shaft 23, and a rotational movement due to a steering operation is input via the steering shaft 23.

[0024] The output shaft 242 has a rotation axis in the vehicle width direction and protrudes from the steering gear box 24. The output shaft 242 rotates to steer the front wheels 40a, and outputs a rotation torque that is amplified compared to the rotation torque input to the input shaft 241.

[0025] One end of the pitman arm 25 is connected to the output shaft 242, and the other end is connected to the drag link 26. The pitman arm 25 pivots back and forth with the rotation of the output shaft 242, with the output shaft 242 as a fulcrum.

[0026] The drag link 26 extends in the front-to-rear direction toward the right front wheel 40a, and one end of the drag link 26 is connected to the pitman arm 25, and the other end is connected to the knuckle arm 27. The drag link 26 moves in the front-to-rear direction of the vehicle 1 due to the swinging motion of the pitman arm 25.

[0027] The drag link 26 is connected to one end of the knuckle arm 27, and a knuckle (not shown) for the right front wheel 40a is connected to the other end of the knuckle arm 27. The knuckle supports the right front wheel 40a and changes the steering angle of the right front wheel 40a.

[0028] The tie rod 28 extends in the vehicle width direction of the vehicle 1, with one end connected to the right knuckle arm 27 and the other end connected to a left knuckle arm (not shown). The tie rod 28 has the function of moving the left knuckle arm in conjunction with the movement of the right knuckle arm 27.

[0029] In the steering device 2 configured in this manner, the rotational movement of the steering wheel 22 is converted into a swinging movement of the pitman arm 25 via the steering gearbox 24, which operates the right knuckle arm 27 via the drag link 26 to change the steering angle of the right front wheel 40a, and further operates the left knuckle arm via the tie rod 28 to change the steering angle of the left front wheel 40a.

[0030] Fig. 3 is an enlarged view of the main part of the steering gear box 24, showing the periphery of the input shaft 241, which is a main part of the steering gear box 24, surrounded by a dashed line frame in Fig. 2. Figs. 4(a) and 4(b) are cross-sectional views taken along the line AA in Fig. 3.

[0031] As shown in FIG. 3, an input gear 241a formed on the input shaft 241, a reduction gear 50, a rotating body 51, a base portion 52, and a regulating portion 53 are provided around the input shaft 241 of the steering gearbox 24.

[0032] The input gear 241 a is a spur gear that rotates integrally with the input shaft 241 .

[0033] The reduction gear 50 is composed of a first gear 50a, which is a spur gear with a larger diameter than the input gear 241a, and a second gear 50b, which is a spur gear with a smaller diameter than the first gear 50a and is provided on the upper surface of the first gear 50a, and these gears are integrally arranged on the same axis. The reduction gear 50 is supported rotatably, and the first gear 50a meshes with the input gear 241a.

[0034] The rotor 51 is made up of a rotor gear 51a, which is a spur gear with a larger diameter than the input gear 241a, and a disk portion 51b, which is provided on the upper surface of the rotor gear 51a and has a generally disk-like shape with a larger diameter than the rotor gear 51a, and which are coaxially integrated together. The rotor 51 is rotatably supported on the input shaft 241 via a bearing 54.

[0035] The rotor gear 51a meshes with the second gear 50b of the reduction gear 50. The disk portion 51b is formed with a protrusion 510 that protrudes radially outward from the outer circumferential surface. The protrusion 510 rotates clockwise or counterclockwise in accordance with the rotation of the rotor 51.

[0036] The base portion 52 is a flat plate that stands upright from the case of the steering gear box 24 toward the upper side in the height direction of the vehicle 1. The height of the base portion 52 is higher than the position of the disk portion 51b of the rotating body 51, and the width of the base portion 52 is longer than the diameter of the rotating body 51 including the protruding portion 510.

[0037] As shown in FIG. 4, the restricting portion 53 is composed of a pair of stopper bolts 531a, 531b and lock nuts 532a, 532b, and is provided at both widthwise ends of the base portion 52. As shown in FIG. 3, the restricting portion 53 is screwed in a state in which the tip ends of the stopper bolts 531a, 531b are inserted into the base portion 52 toward the input shaft 241, and is fixed so as to extend in a substantially horizontal direction. The restricting portion 53 is disposed in a position where the tip ends of the stopper bolts 531a, 531b contact the protruding portion 510 of the rotating body 51, and can restrict the rotation of the rotating body 51 by contacting the protruding portion 510. The restricting portion 53 can adjust the position at which the rotation of the rotating body 51 is restricted by changing the amount of protrusion of the stopper bolts 531a, 531b from the base portion 52. The lock nuts 532a and 532b fix the insertion length of the stopper bolts 531a and 531b.

[0038] In the input shaft 241 portion of the steering gearbox 24 configured in this manner, the rotational motion transmitted from the steering shaft 23 to the input shaft 241 is transmitted to the reduction gear 50 via the input gear 241a, reduced by the reduction gear 50, and then transmitted to the rotating body 51. In this embodiment, the reduction ratio of the reduction gear 50 is set so that the steering wheel 22 rotates 360° or more, whereas the rotating body 51 rotates up to around 180°.

[0039] Next, the restriction of the rotational movement of the steering wheel 22 of the steering device 2 according to this embodiment will be described with reference to FIG.

[0040] 4(a) shows a state in which the vehicle 1 (front wheels 40a) is traveling straight, that is, a state in which the driver is not rotating the steering wheel 22. When the steering wheel 22 is not being rotated, the protruding portion 510 of the rotating body 51 is stationary at a position opposite the base portion 52.

[0041] On the other hand, FIG. 4(b) shows a state in which the vehicle 1 has been steered to the maximum steering angle, that is, a state in which the steering wheel 22 has been rotated by the driver. Specifically, FIG. 4(b) shows a case in which the steering wheel 22 has been rotated to the left (counterclockwise as seen by the driver). In FIG. 4(b), the protrusion 510 comes into contact with the tip of one of the stopper bolts 531b, preventing the steering wheel 22 from rotating any further, and the front wheels 40a of the vehicle 1 are turned to the maximum steering angle. Although not shown, when the steering wheel 22 is rotated to the right (clockwise as seen by the driver), the protrusion 510 comes into contact with the tip of the other stopper bolt 531a, restricting the rotation of the steering wheel 22.

[0042] To adjust the maximum steering angle, if the amount by which the stopper bolts 531a and 531b protrude from the base portion 52 is increased, they will come into contact with the protruding portion 510 sooner, thereby decreasing the maximum steering angle. Conversely, if the amount by which the stopper bolts 531a and 531b protrude from the base portion 52 is decreased, the maximum steering angle will increase.

[0043] As described above, the steering device 2 according to this embodiment restricts the steering of the front wheels 40a by restricting the rotation of the input shaft 241 of the steering gearbox 24 in response to the rotational movement of the steering wheel 22. In other words, the steering device 2 according to this embodiment restricts the steering angle before the steering force is increased by the power steering, so the load on the restricting unit 53 is small, and it is possible to prevent unnecessary load from being applied to the mechanisms connecting the steering shaft 23 to the front wheels 40a (the steering gearbox 24, the pitman arm 25, the drag link 26, the knuckle arm 27, and the tie rod 28). Furthermore, because the restricting unit 53 is provided on the input shaft 241 of the steering gearbox 24, it is easy to adjust the maximum steering angles to the left and right. This allows the steering of the front wheels 40a to be restricted at low cost without the need for sensors or the like, while reducing the load on the mechanisms connecting the steering shaft 23 to the front wheels 40a, and also makes it easy to adjust the maximum steering angle.

[0044] This concludes the description of the embodiment of the present invention, but the aspects of the present invention are not limited to this embodiment.

[0045] In the above embodiment, the steering of the wheel is restricted by the contact of the protruding portion 510 protruding from the disk-shaped rotor 51 with the restricting portion 53, but the contact with the restricting portion may be any part of the rotor, and is not limited to the protruding portion of the disk-shaped rotor. For example, instead of being disk-shaped, the rotor may be a rod-shaped rotor extending radially from a bearing.

[0046] Although the above embodiments are directed to freight vehicles such as trucks, the present invention may also be applied to electric vehicles, vehicles equipped with internal combustion engines, hybrid electric vehicles, and the like. [Explanation of symbols]

[0047] 1 vehicle 2. Steering device 10 Chassis frame 20 Cab 21 Driver's seat 22 Steering wheel 23 Steering shaft 23a Steering column 24 Steering gearbox 241 Input shaft 241a Input gear 242 output shaft 25 Pitman arm 26 Drag Link 27 Knuckle Arm 28 tie rod 30 packing boxes 40 wheels 40a front wheel 40b rear wheel 50 Reduction gear 50a 1st gear 50b 2nd gear 51 Rotating body 51a Rotating gear 51b Disc 510 Protrusion 52 Base 53 Regulatory Department 531a, 531b Stopper bolts 532a, 532b lock nuts 54 Bearings

Claims

[Claim 1] a steering shaft that transmits rotational motion to the steering wheel; a steering gearbox having an input shaft connected to the steering shaft and converting the rotational movement of the steering wheel into an operation for steering wheels; a reduction gear provided on the steering shaft and the input shaft of the steering gearbox for converting the rotational motion of the steering wheel into a rotational motion slower than that of the steering wheel; a rotating body that rotates at a reduced speed compared to the rotation of the steering wheel via the reduction gear; a restricting portion that comes into contact with a part of the rotating body to restrict rotation of the rotating body, and the position at which the rotation is restricted is adjustable; A steering device for a vehicle comprising:

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