JP2022155387A - Rack-and-pinion system - Google Patents

Abstract

To obtain a large stroke with a short rack.SOLUTION: A rack-and-pinion system 100 includes: a rack shaft body 110; a pinion shaft body 120 extending in a pinion shaft direction that is orthogonal to a rack axis; a rack housing 130 which houses the rack shaft body 110, and the pinion shaft body 120 in an inserted state, and has a length of a rack area being an area where a rack 111 is formed, or less; and a first support member 141 and a second support member 142 that support the rack shaft body 110 relative to the rack housing 130, and are disposed on both sides of the pinion shaft body 120 in a rack axis direction. In the rack-and-pinion system, a length in the rack axis direction of a support member area that is an area where the first support member 141 and the second support member 142 are arranged, is shorter than a length of the rack area.SELECTED DRAWING: Figure 4

Description

The present invention relates to a rack and pinion system in which a rack and a pinion are meshed and capable of mutually converting rotation and linear motion.

Conventionally, there is a rack-and-pinion system, such as the steering device described in Patent Document 1, that converts the rotation of a steering wheel into a linear motion that turns steered wheels. 2. Description of the Related Art In a rack-and-pinion system incorporated in a steering device of a passenger car, a pair of support members called rack bushes for accommodating the rack shaft are arranged in a rack housing for accommodating the rack shaft. A pair of support members are arranged at both ends of the rack housing, support the rack shaft, and guide the linear movement of the rack shaft. If the rack shaft has a length that extends from the vicinity of one steered wheel to the vicinity of the other steered wheel, even if the stroke of the rack shaft is increased, the support members arranged at both ends of the rack housing do not move. The rack shaft does not come off.

JP 2016-155443 A

However, in the case of a vehicle in which the rack and pinion system is arranged in a direction other than the width direction of the vehicle and the steered wheels are steered via a drag link or the like, it is necessary to extend the rack shaft body long in the width direction of the vehicle. Therefore, it was difficult to secure a large stroke of the rack shaft body.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rack and pinion system capable of ensuring a large stroke of the rack shaft even when the length of the rack shaft is short.

To achieve the above object, one aspect of the present invention is a rack and pinion system comprising: a rack shaft body having a rack formed in a rack axial direction; A pinion shaft in which a pinion meshing with a rack is formed, and a length of a rack region in which the rack shaft and the pinion shaft are accommodated in an inserted state and in which the rack is formed in the rack axial direction. a rack housing, and a first supporting member and a second supporting member that support the rack shaft relative to the rack housing and are arranged on both sides of the pinion shaft in the rack axial direction, The length in the rack axial direction of the support member region where the first support member and the second support member are arranged is shorter than the length of the rack region.

According to the present invention, the pair of support members that support the rack shaft are arranged near both sides of the pinion. No falling off.

1 shows a steering device with a rack and pinion system; FIG. It is a perspective view showing a rack and pinion system. It is a perspective view which shows a rack and pinion system with a rack housing in a transparent state. 1 is a cross-sectional view of a rack and pinion system; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a rack and pinion system according to the present invention will be described below with reference to the drawings. It should be noted that the following embodiments are examples for explaining the present invention, and are not intended to limit the present invention. For example, the shapes, structures, materials, constituent elements, relative positional relationships, connection states, numerical values, formulas, contents of each step in the method, order of each step, etc. shown in the following embodiments are examples, and are described below. may include content not listed in In addition, geometric expressions such as parallel and orthogonal are sometimes used, but these expressions do not indicate mathematical rigor, and substantially allowable errors, deviations, and the like are included. Expressions such as "simultaneous" and "identical" also include substantially permissible ranges.

In addition, the drawings are schematic diagrams that have been appropriately emphasized, omitted, or adjusted in proportion in order to explain the present invention, and are different from the actual shape, positional relationship, and proportion.

Further, in some cases, a plurality of inventions will be collectively described as one embodiment below. Also, some of the contents described below are described as optional components related to the present invention.

FIG. 1 shows a steering device with a rack and pinion system. The steering device 200 is a mechanism for turning steerable wheels 210 by operation of a driver or a computer to steer the vehicle, and the rack and pinion system 100 is incorporated. Although the type of the steering device 200 is not particularly limited, in the case of the present embodiment, the rack and pinion system 100 converts the rotation of an operation member 250 such as a steering wheel into linear motion, and the link mechanism 220 converts the rotation. A form in which the steering wheel 210 is steered is adopted. Specifically, steering device 200 includes rack and pinion system 100 , drag link 221 , bell crank 222 , relay rod 223 , tie rod 224 and knuckle arm 225 . The steering device 200 is a so-called power-assisted steering device 200 that includes a speed reducer 230 and a motor 240, and inputs an assist torque to the pinion side to assist the operation torque input by the driver through the operation member 250. be. Further, the steering device 200 is capable of automatic steering during automatic driving by controlling the motor 240 with a computer.

FIG. 2 is a perspective view showing the rack and pinion system. FIG. 3 is a perspective view showing the rack and pinion system with the rack housing in a transparent state. FIG. 4 is a cross-sectional view of the rack and pinion system. As shown in these drawings, the rack and pinion system 100 includes a rack shaft 110, a pinion shaft 120, a rack housing 130, a first support member 141, and a second support member 142. In the case of this embodiment, rack and pinion system 100 includes stopper 150 , rack guide 160 , and connection member 113 .

The rack shaft 110 is a rod-shaped member in which a rack 111 is formed in the rack axial direction (the Y-axis direction in the drawing). Convert motion to linear motion.

The shape of the rack shaft body 110 is not particularly limited, but in the case of the present embodiment, the rack shaft body 110 has a rack 111 formed in the central portion in the rack axial direction. As shown in FIG. 4, the length L1 in the rack axial direction of the rack area where the rack 111 is formed is at least half the length of the rack shaft. Non-rack portions 112 in which the racks 111 are not formed are present at both ends of the rack shaft body 110 . The length L1 of the rack area in the rack axial direction is longer than the total length (L3+L4) of the non-rack areas where the two non-rack portions 112 are present.

The pinion shaft 120 is a rod-shaped member formed with a pinion 121 that extends in a pinion axis direction that intersects the rack axis and meshes with the rack 111 . In the case of the present embodiment, pinion shaft 120 is connected to operating member 250 via steering shaft 260, and is rotated when operating member 250 is rotated by the driver. Further, the pinion shaft 120 is connected to a motor 240 via a speed reducer 230, and the torque generated by the motor 240 is input.

The rack housing 130 is a housing that accommodates the rack shaft 110 and the pinion shaft 120 in an inserted state, holds the rack shaft 110 so as to guide linear motion, and holds the pinion shaft 120 rotatably. do. In the rack axial direction, the length L5 (see FIG. 4) of the rack housing 130 is set to be equal to or less than the length L1 of the rack area where the rack 111 is formed. This makes it possible to avoid interference with members such as the drag link 221 connected to the rack shaft 110 even when the stroke of the rack shaft 110 is large. The rack housing 130 has a cylindrical guide accommodating portion 131 that holds the rack guide 160 in an accommodated state on the side opposite to the pinion 121 with respect to the rack shaft 110 .

At both left and right ends of the rack housing 130 , expandable bellows-structured boots (not shown) are provided to prevent dust from entering the rack housing 130 .

The first support member 141 and the second support member 142 (these may be collectively referred to as “support members”) contact the rack shaft 110 with respect to the rack housing 130 to directly support the rack. It is a member called a bush or the like that directly guides the linear motion of the shaft 110, and is a member arranged on both sides of the rack shaft 110 with the pinion shaft 120 interposed therebetween in the rack axial direction. From the length L6 (see FIG. 4) in the rack axial direction of the support member region where the first support member 141 and the second support member 142 are arranged, that is, from the outer end of the first support member 141 in the rack axial direction The length to the outer end of the second support member 142 is arranged so as to be shorter than the length L1 of the rack area in which the rack 111 is arranged.

The support member is a member that resists the force received from the drag link 221 in the direction intersecting the rack axial direction and maintains the positional relationship of the rack shaft 110 so that the rack shaft 110 does not tilt with respect to the rack housing 130 . . The shape of the support member is not particularly limited as long as it has a portion that fills the space between the surface opposite to the surface on which the rack 111 is formed and the rack housing 130. In this case, the support member has a cylindrical shape. Moreover, each supporting member may be formed of one member, or may be formed of a plurality of members.

The stopper 150 abuts on the outer end surface of the first support member 141 or the second support member 142 to restrict movement of the rack shaft body 110 in the rack axial direction. In this embodiment, the stopper 150 enters the inside of the rack housing 130 and contacts the outer end surface of the first support member 141 to restrict the movement of the rack shaft 110 . This prevents the pinion 121 from riding on the non-rack portion 112 of the rack shaft 110 . A drag link 221 is connected to the side opposite to the stopper 150 , and the movement of the rack shaft body 110 is restricted by the link mechanism of the steering device 200 .

The rack guide 160 is a mechanism that urges the rack shaft 110 toward the pinion shaft 120 so as to resist the meshing reaction force between the rack 111 and the pinion 121 . The rack guide 160 is housed within a guide housing portion 131 provided in the rack housing 130 . The rack guide 160 abuts against the rack shaft 110 on the side opposite to the side on which the rack 111 is formed. It has a biasing member 162 that biases the support yoke 161 so as to press it against 120, and a pressing member 163 that is fixed to the end of the guide housing portion 131 on the opening side and maintains the biasing member 162 in a compressed state. .

The connection member 113 is a member that connects the drag link 221 to the rack shaft 110 so as to be able to swing. In the case of this embodiment, the outer diameter of connecting member 121 is set larger than the outer diameter of rack shaft 110 and smaller than the inner diameter of rack housing 130 . As a result, the connection member 113 can enter the rack housing 130 and come into contact with the second support member 142 , and can exhibit the same function as the stopper 150 that restricts the movement of the rack shaft 110 .

According to the rack and pinion system 100 of the present embodiment, since the length of the region where the support member is arranged in the rack axial direction is short, the rack shaft 110 can be supported by the support member even when the rack shaft 110 is short. The rack shaft body 110 can be moved to the very limit. Therefore, it is possible to increase the stroke of the rack shaft body 110 .

In addition, since the length of the region where the support member is arranged is short, the length of the rack housing 130 that holds the rack shaft body 110 via the support member can also be shortened. can suppress interference with

In addition, in the rack axial direction, the length of the support member region L6 is shorter than the length of the rack housing 130, and the stopper 150 and the connecting member 113 can enter the inside of the rack housing 130. Therefore, the stroke of the rack shaft 110 is A large amount can be secured.

It should be noted that the present invention is not limited to the above embodiments. For example, another embodiment realized by arbitrarily combining the constituent elements described in this specification or omitting some of the constituent elements may be an embodiment of the present invention. The present invention also includes modifications obtained by making various modifications to the above-described embodiment within the scope of the gist of the present invention, that is, the meaning of the words described in the claims, which a person skilled in the art can think of. be

For example, although the pinion 121 is a spur gear and the rack 111 is a straight tooth, the pinion 121 may be a helical tooth and the rack 111 may be a helical tooth rack.

Moreover, although the case where the rack and pinion system 100 is incorporated in the link-type steering device 200 has been described, the rack and pinion system 100 may be incorporated in another type of steering device 200, or in a device other than the steering device 200. may be incorporated into

INDUSTRIAL APPLICABILITY The present invention can be used for a rack and pinion system that mutually converts rotation and linear motion.

DESCRIPTION OF SYMBOLS 100... Rack and pinion system, 110... Rack shaft, 111... Rack, 112... Non-rack part, 113... Connection member, 120... Pinion shaft, 121... Pinion, 130... Rack housing, 131... Guide accommodating part, 141 First supporting member 142 Second supporting member 150 Stopper 160 Rack guide 161 Support yoke 162 Biasing member 163 Holding member 200 Steering device 210 Steering wheel 220 Link mechanism 221 Drag link 222 Bell crank 223 Relay rod 224 Tie rod 225 Knuckle arm 230 Reducer 240 Motor 250 Operating member 260 Steering shaft

Claims (4)

a rack shaft having a rack formed in the rack axial direction;
a pinion shaft extending in a pinion axis direction that intersects with the rack shaft and formed with a pinion that meshes with the rack;
a rack housing that accommodates the rack shaft and the pinion shaft in an inserted state and has a length in the rack axial direction equal to or less than a rack region in which the rack is formed;
a first supporting member and a second supporting member that support the rack shaft with respect to the rack housing and are arranged on both sides of the pinion shaft in the rack axial direction;
A rack and pinion system in which the length in the rack axial direction of a support member region in which the first support member and the second support member are arranged is shorter than the length of the rack region. 2. The rack and pinion system according to claim 1, wherein the length of the rack region in the rack axial direction is half or more of the length of the rack shaft. 3. The rack and pinion system according to claim 1, further comprising a stopper that abuts on the outer end surface of the first support member or the second support member and restricts movement of the rack shaft in the rack axial direction. The rack and pinion system according to any one of claims 1 to 3, wherein the length of the support member region is shorter than the length of the rack housing in the rack axial direction.

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