JPH0439809Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to a steering amount transmission mechanism configured to take out the steering amount of a steering shaft from the outer surface of a gearbox in a rack-and-pinion type steering device, and the steering amount detection information taken out in this way is transmitted to a steering amount display device. It can also be used as input information for rear wheel steering control in a four-wheel steering vehicle.

[Prior art and its problems]

Conventionally, in order to detect the direction and amount of steering of the front wheels, a disk with a large number of transparent slits bored in an annular shape,
It is common to provide a steering sensor on the steering shaft with a photo interrupter arranged to sandwich the disc. The area around the steering shaft inside the instrument panel is equipped with various handheld switches for driving, a tilt mechanism, a steering wheel lock mechanism to prevent theft, and a shock absorption device to protect occupants in the event of a collision, making it extremely cramped. However, due to the fact that there is no suitable part outside that can detect the amount of rotation of the steering wheel, it has to be installed inside the instrument panel. However, since the steering sensor is not directly operated by the driver, it is not necessary to install it around the steering shaft in the small instrument panel. For example, if it is placed in the engine room, the space inside the instrument panel can be used more effectively. You will be able to do this. By the way, if the above-mentioned steering sensor is placed in the engine room, it would be easy to use, for example, to extract the steering amount as the amount of rotation.
A conceivable structure is that a sub rack is cut in the middle part of the rack rod in a pinion type steering device, and a sub rack is meshed with the sub rack, which is rotatably supported so as to pass through the peripheral wall of the gearbox. However, if you try to adopt this structure,
The following issues that need to be resolved will emerge. In conventional rack and pinion steering systems, the rack rod is supported within the gearbox at substantially two points at each end of the rack rod. That is,
In the case of a right-hand drive vehicle, the rack lever is supported at its left end so as to be slidable against the inner surface of the gearbox via a rack bushing, and at its right end, as shown in FIG. It is supported by being sandwiched between a pinion that meshes with the pinion and a rack guide that is elastically abutted against the surface facing the pinion. The sliding surface of the rack guide a has a cylindrical inner surface that hugs the cylindrical peripheral surface of the rack so that the rack b does not shift in a direction parallel to the axis of the pinion c. By the way, when adding the above-mentioned auxiliary rack and the auxiliary pinion that meshes with it to such a conventional rack and pinion type front wheel steering device, the rack includes the rack bushing, the input pinion part from the steering shaft, and the above-mentioned auxiliary rack. The sub pinion part is supported at three points, and in order to ensure smooth sliding of the rack, the positional accuracy of these three support points, especially in the direction orthogonal to the longitudinal direction of the rack rod, and the rack Accuracy of the rod itself is required. However, if the three supporting points mentioned above are not substantially on a straight line, or if the rack rod itself is not straight, a bending force will act on the rack rod after assembly, and this will affect the sliding of the rack rod. This is because it acts as a large resistance against This invention was devised under the above-mentioned circumstances, and the problems to be solved are the accuracy and accuracy of the rack rod support by three points: the rack bush, the input pinion, and the auxiliary pinion for detecting the amount of steering. It is possible to achieve even smoother axial operation of the rack rod while not requiring so much precision of the rack rod itself, and to provide a portion outside the dash panel where the amount of steering can be extracted as the amount of rotation. The purpose of the present invention is to install it without any inconvenience on the outer surface of the gearbox of a rack-and-pinion steering system located in the engine room of a vehicle.

[Means for solving the problem] In order to solve the above problem, the present invention takes the following technical measures. That is, an auxiliary rack is formed in the middle of the rack rod of a rack and pinion type front wheel steering mechanism, and a auxiliary pinion rotatably supported by a gearbox is meshed with this auxiliary rack, and the rotation of this auxiliary pinion is directed to the outside. In the steering device configured to be taken out, the axis of the input pinion from the steering shaft and the axis of the auxiliary pinion are substantially perpendicular to each other, and a first rack guide is elastically pressed against the surface of the rack rod facing the input pinion; The second roller is configured of a cylindrical roller rotatable around an axis that is parallel or substantially parallel to the axis of the input pinion when viewed in the axial direction of the rack rod, and is elastically pressed against the surface of the rack rod that faces the sub pinion. The rack guide is characterized in that it is constituted by a cylindrical roller rotatable around an axis that is parallel or substantially parallel to the axis of the sub pinion when viewed in the axial direction of the rack rod.

[Effect]

Now, the point where the rack rod is supported by the rack bushing is point A, the point where it is supported between the auxiliary pinion and the second rack guide is point B, and the point where it is supported between the input pinion and the first rack guide is point C. Point.
Normally, these points are arranged in the order of A, B, and C toward the front of the vehicle body. Since point A is supported by a bushing surrounding the rack rod, movement of the rack rod in the direction perpendicular to its axis is restricted. At points B and C, the cylindrical outer surface of each cylindrical roller rack guide is parallel to the axis of the input pinion and the axis of the sub pinion, respectively, when viewed in the axial direction of the rack rod.
In the plane perpendicular to the axis of the rack rod,
Movement in the direction of the line connecting the pinion and rack guide is restricted, but movement in the direction parallel to the axis of the pinion is free. In addition, by making the axis of the input pinion and the axis of the sub pinion almost orthogonal,
At points B and C, the restricting directions for the rack rods that connect the pinion and the rack guide are almost perpendicular to each other, so the rack rods are free to move in a certain direction at points B and C as described above. Also, the position of the rack rod in the direction perpendicular to the axis is
It is determined.

【effect】

From the above, even if there is an error in the position of points B and C with respect to the above point A in the direction perpendicular to the axis of the rack rod, in other words, there is an error in the direction perpendicular to the axis of the rack rod in the mounting position of the input pinion or auxiliary pinion. Even if this occurs, the escape movement of the rack rod in a predetermined direction perpendicular to the axis relative to the gearbox is allowed at points B and C, so that unnecessary bending force due to the above error does not act on the rack rod. This means that smooth operation of the rack rod can be achieved even if the assembly accuracy of the point C support section, which consists of the input pinion and the first rack guide, and the point B support section, which consists of the auxiliary pinion and the second rack guide, is not very accurate. This also means that the straightness of the rack rods is not as demanding. This makes it easy to
The amount of steering can be conveniently taken out from the gearbox of the pinion type steering device as rotation of the auxiliary pinion. In addition, since both the first and second rack guides are constituted by rotatable cylindrical rollers, the smoothness of the operation of the rack rods is dramatically improved compared to the prior art.

[Explanation of Examples]

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Figures 1 to 5 show examples of four-wheel steering devices configured to mechanically move a rear wheel steering mechanism using the steering force taken out by the steering amount transmission mechanism of the present invention. show. As is clear from FIG. 1, this four-wheel steering device 1 extracts the movement of a rack rod 3 in a front wheel steering mechanism 2 of the rack and pinion type by an auxiliary pinion 5 rotatably supported by a gearbox 4. The rotation of the auxiliary pinion 5 is inputted via a transmission shaft 6 to a rear wheel steering mechanism 7 arranged at the rear of the vehicle body. In this example, the rear wheel steering mechanism 7 is configured as a so-called center arm type, and converts the rotation of the transmission shaft 6 input into the mechanism box 8 into a swing of a center arm 9 provided in the mechanism box 8 in a predetermined direction and at a predetermined angle. This movement of the center arm 9 is transmitted to the rear wheels 11, 11 via a pair of left and right tie rods 10, 10.
It is configured to transmit the rotation of the knuckle arms 12, 12 attached to the rotor. On the other hand, the front wheels 13,
Reference numeral 13 denotes a pair of left and right tie rods 14, 14 connected to both ends of the rack rod 3 in the gear box 4.
The movement is transmitted to the knuckle arms 15, 15 for steering. The gearbox 4 of the front wheel steering mechanism has a substantially cylindrical shape as shown in FIG. 2, and a rack rod 3 is supported therein so as to be movable in the axial direction. The rack rod 3 has its left end supported so as to be movable in the axial direction via the rack bush 16, and its right end and intermediate portion serve as an input section for inputting rotation from the steering shaft 17 near the right end of the gearbox 4. 18, and an output section 19 which outputs a steering force for the rear wheel steering mechanism 7 at an intermediate portion of the gearbox 4. The configuration of the input section 18 and output section 19 is changed to a third one.
This is specifically shown in FIG. As shown in FIG. 3, the gearbox 4 includes a pinion housing part 21 which rotatably accommodates and supports an input pinion 20 which is input diagonally forward and downward on the upper side of the rack rod 3, and A cylindrical rack guide housing part 23 that accommodates and holds a first rack guide 22, which will be described later, is integrally formed on the opposite side of the pinion housing part 21. A spring 2 is provided inside the rack guide housing part 23.
A piston-shaped support body 25 urged toward the rack rod 3 by the rack lever 4 is slidably mounted, and a first roller 22' serving as a first rack guide 22 is rotatably mounted on the top of the support body 25. is supported by
The circumferential surface of the first roller 22' has a cylindrical shape, and therefore the guide surface 22a of the first roller 22' has the following shape when viewed in the axial direction of the rack rod, as shown in FIG. It has a straight line shape extending in a direction parallel to the axis of the input pinion 20. This guide surface 22a is brought into contact with a flat portion 3a formed on the rack rod 3. As a result, the rack rod 3 is basically sandwiched between the input pinion 20 and the first roller 22', which are arranged to face each other diagonally up and down, and is connected to the input pinion 20 and the first roller 22' with respect to the gearbox 4. Relative movement in the direction of line a connecting roller 22' is restricted. However, due to the meshing relationship between the rack and pinion and the fact that the cylindrical circumferential surface of the first roller 22' is brought into contact with the flat portion 3a formed on the rack rod 3, the rack rod 3 is line perpendicular to a
It can move freely in the a' direction (the direction parallel to the axis La of the input pinion when viewed in the axial direction of the rack rod). On the other hand, in the output part 19, as shown in FIG. 4, a sub-pinion housing part 27 is formed below the rack rod 3 to rotatably accommodate and hold a sub-pinion 26 that is output diagonally downward and rearward. A cylindrical rack guide housing part 29 is integrally formed on the opposite side of the pinion housing part 27 with the rack rod 3 in between, and accommodates and holds a second rack guide 28 to be described later. An auxiliary rack 32 that meshes with the auxiliary pinion 26 is formed on the diagonally lower surface of the rack rod 3. Inside the rack guide housing section 29, a rack rod 3 is provided by a spring 30, similar to the input section 18 described above.
A piston-shaped support body 25 is slidably loaded and is biased toward the top of the support body 25, and a second roller 28' serving as a second rack guide 28 is rotatably supported on the top of the support body 25. This second roller 28'
The peripheral guide surface 28a also has a cylindrical surface shape like the first roller 22', and is brought into contact with a flat portion 3b formed on the rack rod 3. As a result, the rack rod 3 is sandwiched between the auxiliary pinion 26 and the second roller 28', which are arranged to face each other diagonally up and down, and is positioned between the auxiliary pinion 26 and the second roller 28' relative to the gearbox 4. Relative movement in the direction of the connecting line b is restricted. however,
Due to the meshing relationship of the rack and pinion and the fact that the cylindrical circumferential surface of the second roller 28' is brought into contact with the flat portion 3b formed on the rack rod 3, the rack rod 3 is aligned with the line b. Orthogonal line b′ direction (auxiliary pinion axis Lb when viewed in the axial direction of the rack rod)
can move freely in the direction parallel to As is clear from a comparison of FIGS. 3 and 4, the axis La of the input pinion 20 and the axis Lb of the auxiliary pinion 26 intersect at almost a right angle, so that the rack rod 3 is restricted at the input section 18. The direction in which the rack rod 3 is regulated, that is, the line a, and the direction in which the rack rod 3 is regulated at the output section 19, that is, the line b, are substantially perpendicular to each other. Together with the above, the position of the rack rod 3 in the direction orthogonal to the axis is defined. However, in the present invention, as described above, the input section 18 allows the rack rod 3 to move freely in the direction of the line a', and the output section 19 allows the rack rod 3 to freely move in the direction of the line b'. Therefore, the mounting precision of the pinions, etc. of the input section 18 and the output section 19, and the straightness of the rack rod 3 itself are not required so much. That is, for example, in the schematic diagram of FIG.
Even if an error in the direction of line a occurs in the position of , and a force in the direction of line a acts on the rack rod 3, the rack rod 3 can escape in the direction of line b' at the output section 19, so the rack rod 3 is No bending force is applied,
This ensures smooth axial movement. Furthermore, since the first and second rack guides 22 and 28 that guide the rack rod 3 are both composed of rotatable cylindrical rollers, only rolling friction acts between them and the rack guide when the rack rod 3 is operated. First, this greatly increases the smoothness of the operation of the rack rod 3. This means that the mechanical power loss from the input pinion to the auxiliary pinion can be significantly reduced.For example, it can be used as a steering force extraction device for the rear wheel steering mechanism of the four-wheel steering system shown in Fig. 1. When the present invention is applied, the rear wheel steering mechanism can be operated without any problem without so-called power assist. In this way, the mechanical transmission type four-wheel steering device can be made lighter and cheaper than before. Of course, the scope of the present invention is not limited to the embodiments described above. For example, even if the axis La of the input pinion 20 and the axis Lb of the auxiliary pinion 26 are not exactly perpendicular to each other, if they intersect substantially perpendicularly, the position of the rack rod 3 in the direction perpendicular to the axis can be determined.
Further, in the embodiment, a flat surface is formed on the surface of the rack rod 3 that the first rack guide 22 and the second rack guide 28 come into contact with, but it is not necessary to provide this flat surface. Further, in the above embodiment, the steering amount taken out from the output section is transmitted to the rear wheel steering mechanism, but as shown in FIG. 6, the auxiliary pinion 2
6 is configured to have an output direction opposite to that in the above embodiment, and a steering sensor 31 is connected to this pinion 26.
It is also possible to provide a.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of a four-wheel steering system to which the present invention is applied, Fig. 2 is a partially cutaway plan view of the steering force transmission mechanism, Fig. 3 is a sectional view taken along the line - - of Fig. 2, and Fig. 4 is a partially cutaway plan view of the steering force transmission mechanism. The figure is a sectional view taken along the line - in Fig. 2, Fig. 5 is a schematic diagram of the main structure of the present invention, Fig. 6 is a sectional view of another embodiment of the present invention, and Fig. 7 is a conventional rack and pinion. FIG. 3 is an explanatory diagram of a rack guide in the type steering mechanism. 1... Four-wheel steering device, 2... Front wheel steering mechanism, 3
...Rack rod, 4...Gear box, 5...Sub pinion, 17...Steering shaft, 20...
...Input pinion, 22...First rack guide, 2
2a...Guide surface, 28...Second rack guide,
28a...Guide surface, 32...Sub-rack, La...
...(Input pinion) shaft, Lb...(Sub pinion) shaft.

Claims (1)

[Claims for Utility Model Registration] A sub-rack is formed in the middle of the rack rod of a rack-and-pinion type front wheel steering mechanism, and a sub-pinion rotatably supported by the gear box is meshed with this sub-rack. In a steering device configured to extract the rotation of the pinion to the outside, the axis of the input pinion from the steering shaft and the axis of the auxiliary pinion are made almost orthogonal, and the pinion is elastically pressed against the surface of the rack rod facing the input pinion. The first rack guide is configured with a cylindrical roller rotatable around an axis that is parallel or substantially parallel to the axis of the input pinion when viewed in the axial direction of the rack rod. A steering amount in a steering device, characterized in that the second rack guide that is pressed against the rack rod is constituted by a cylindrical roller rotatable around an axis that is parallel or substantially parallel to the axis of the auxiliary pinion when viewed in the axial direction of the rack rod. transmission mechanism.