JPS58105880A - Steering gear for vehicle - Google Patents

Abstract

PURPOSE:To contrive to make compact a rear-wheel steering gear, by a method wherein a drum is connected to an input shaft rotated being interlocked with a steering wheel, a cam groove is provided on the outside peripheral surface of the drum, and an engaging element of a rear-wheel steering mechanism is slidden in the cam groove. CONSTITUTION:The drum 22 is connected to the input shaft 21, and the outside surface of the drum 22 is provided with the cam groove 19. Inner end parts of tie rod 20, 20 are connected to a link member 23, and a pin (engaging element) 24 of the link member 23 is slidably engaged into the cam groove 19. When the drum 22 is rotated together with the input shaft 21 by the steering wheel 10, the pin 24 is moved by the cam groove 19, whereby the tie rods 20, 20 are moved leftwards or rightwards through the link member 23, and rear wheels 4, 4 are steered. Accordingly, it is contrived to make compact the rear-wheel steering gear, and the steering gear can be effectively placed in a limited space in the vehicle body.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle steering device that steers front wheels and rear wheels by steering operation of a steering wheel.

The present applicant has provided a vehicle steering system in which the rear wheels can be steered together with the front wheels by first steering the steering wheels. Specifically, in this device, the rear wheels are steered in the same direction as the front wheels when a small steering angle operation of the steered wheels is performed while the vehicle is running at high speed, thereby improving the maneuverability of the vehicle. When operating the steering wheel at a large steering angle while driving at low speed, the rear wheels are steered in the opposite direction to the front wheels.
By reducing the difference between the inner wheels of the rear wheels and the turning radius, it is possible to improve maneuverability of steering wheels.

By the way, in a steering system that steers the rear wheels together with the front wheels, it is necessary to assemble the rear wheel steering mechanism and other related mechanisms, parts, etc. to the vehicle body more than in a general vehicle that steers only the front wheels. be. Since a vehicle is composed of a large number of members, devices, etc., the rear wheel steering device including the rear wheel steering mechanism and related mechanisms is required to be compact in view of space constraints.

Regarding rear wheel steering operation, when a vehicle is running at high speed and the steered wheels are operated by a small steering angle, the rear wheels are steered in the same direction as the front wheels. It is desirable to do this with a good steering angle. This is because if the rear wheel turning angle is larger than the front wheel turning angle, the moving direction of the vehicle's center of gravity and the yawing direction around a vertical line passing through the vehicle's center of gravity will be in opposite directions, making maneuvering difficult. However, on the other hand, when the steered wheels are operated at a large steering angle while the vehicle is running at low speed, the rear wheels are steered in the opposite direction to the front wheels. In order to further improve the steering wheel steering operability, it is desirable to use a large rear wheel steering angle. In order to put the steering system into practical use, it is necessary to make the rear wheel steering angles different at different times, rather than making them the same.

The present invention has been made in order to meet the above-mentioned demands in putting a steering system into practical use.

An object of the present invention is to provide a steering system for a vehicle in which front wheels and rear wheels are steered by steering operation of a steered wheel, in which a drum is connected to an input shaft that rotates in conjunction with the steered wheel, and the drum is connected to an input shaft that rotates in conjunction with the steered wheel. By forming a cam groove for rear wheel steering on the outer circumferential surface of the drum, and slidably engaging a pin provided in the rear wheel steering mechanism with the cam groove, the rear wheel follows the shape of the cam groove as the drum rotates. The main components of the rear wheel steering device that determines the rear wheel steering operation can be configured with a small drum, and the rear wheel steering device can thus be made more compact. Placement Space 4 - It is advantageous in terms of pace to provide a steering system for a vehicle.

Another object of the present invention is to adjust the shape of the cam groove formed on the outer circumferential surface of the drum so that the maximum steering angle of the rear wheels is adjusted when the rear wheels are steered in the same direction as the front wheels. The maximum steering angle of the rear wheels is set to be large when the rear wheels are steered in the opposite direction to the front wheels during large steering angle operations, thereby enabling high-speed driving in which small steering angle operations are performed. By making it possible to make the steering angle of the rear wheels smaller than the steering angle of the front wheels while maintaining improved maneuverability, it is possible to increase the steering angle of the rear wheels during low-speed driving when large steering angle operations are performed. An object of the present invention is to provide a steering system for a vehicle that can further reduce the difference between the inner wheels of the front and rear wheels and the turning radius, and further improve the maneuverability of steering wheels.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view schematically showing the basic structure of a vehicle, omitting devices, members, etc. that are unnecessary for explaining the present invention, such as an engine.

The left and right front wheels 1.1 have knuckle arms 2 that can rotate left and right,
left and right front wheel steering tie rods 3.3 supported by 2 and having outer ends connected to the front wheel knuckle arms 2, 2;
By moving left and right, the front wheel 1.1 is steered by rotation of the knuckle arm 2.2. The left and right rear wheels 4°4 have knuckle arms 5.5 that can rotate left and right like the front wheels.
left and right rear wheel steering tie rods 2 supported by the left and right rear wheel steering tie rods 2 whose outer ends are connected to the rear wheel knuckle arms 5, 5;
0.20 moves left and right, the rear wheels 4, 4 are steered by rotation of the knuckle arm 5.5. The front wheel knuckle arm 2 is suspended on the vehicle body by a lower arm 6, a shock absorber 7, etc. that constitute a front wheel suspension mechanism, and the rear wheel knuckle arm 5 is also suspended on the vehicle body by a lower arm 8, a shock absorber 9, etc. that constitute a rear wheel suspension mechanism. suspended in the.

A steering shaft 11 is integrally connected to a steering wheel 10 which is rotated by a driver, and a lower end of the steering shaft 11 is inserted into a gear box 12 . Inside the gear box 12, a motion direction conversion mechanism is incorporated that converts the rotation of the steering shaft 110 by the steering wheel 10 into a shaft 13 nion system, and when the steering wheel 1o is steered, a tie rod whose inner end is connected to the shaft 13 3.6 moves left and right, and the front wheels 1.1 are steered as described above. The front wheel steering mechanism described above is the same as a known one.

A connecting shaft 14 connected to the internal mechanism of the gear box 12 projects rearward from the gear box 12, and the front end of an operating shaft 15 whose length direction is in the longitudinal direction of the vehicle body is connected to the connecting shaft 14 by a universal joint 16. Further, a shaft 21 is connected to the rear end of the operating shaft 15 via a universal joint 17. The internal mechanism of the gear box 12 connects the rotation of the steering shaft 11 to the connecting shaft 1.
For example, the shaft 21 rotates in conjunction with the steered wheel 1o, and the rotational force is transmitted from the steered wheel 1o.

When the shaft 21 rotates, the rear wheel steering device, which will be described later, operates to steer the rear wheels.
This is the input shaft that inputs the steering torque applied to the rear wheel steering device. In order to rotate the input shaft 21 by moving the steering wheel 1o in a series of =7, the steering shaft 1
1 is provided with a gear box different from the gear box 12,
The shaft may be connected to the steering shaft 11 via a gear mechanism such as a bevel gear or a worm gear built into the gear box, and the input shaft 21 may be connected to the shaft.

As shown in FIG. 2, a tram 22, which is a main component of the rear wheel steering device, is connected and integrated with the input shaft 21. The drum is supported so as to be rotatable, and the drum is supported horizontally with the axial direction of the drum as the longitudinal force direction of the vehicle body. A link member 23 having a planar shape of a square mark is attached to the bracket 18 so as to be swingable in a horizontal plane about a shaft 23a.
A pin 24 is fixed to the tip of the first extending portion 23b that constitutes the link member 23 and has a length in the vehicle width direction, that is, the left-right direction, and a second extending portion 2 that has a length in the vehicle front-rear direction.
Joint pins 25, 25 are provided at the tip of 3C. The link portion 23 constitutes a rear wheel steering mechanism together with the left and right rear wheel steering tie rods 20.20, and the tie rods 20.
The inner end of 20 is connected to the link member 23 by a joint pin 25.25, and the pin 2 provided in the link member 26
4 is slidably engaged with a rear wheel steering cam groove 19 formed on the outer peripheral surface of the drum 22, and the pin 24 serves as a retainer that engages with the cam groove 19.

The rear wheel steering device is constituted by the drum 22 and the rear wheel steering mechanism described above, and since the tram 22, which determines the operation mode of the rear wheel steering operation by the shape of the cam groove 19, is small, the rear wheel steering device as a whole is configured. It can be made compact, and the rear wheel steering device can be installed effectively in a limited space of the vehicle.

When the drum 22 is rotated together with the input shaft 21 by the steering wheel 10, the cam groove 19 has a length component in the drum length direction, that is, in the longitudinal direction of the vehicle body, in addition to a length component in the drum circumferential direction. Holder 2 that follows the cam groove shape
4, the first extension part 23b of the link member 26 swings in the longitudinal direction of the vehicle body around the shaft 23a, and the second extension part 23C swings in the left-right direction accordingly, for steering the left and right rear wheels. Tie rod 20.20 moves left and right,
Rear wheel 4.40 steering is performed. The rear wheels can be steered together with the front wheels steered by the front wheel steering mechanism.

As shown in FIG. 3, the diameter of the drum 22 gradually increases from the central part in the longitudinal direction of the drum toward both ends 22a, 231) of the drum.
Even when the link member 26 swings in a horizontal plane about the shaft 23a, the engaging element 24 does not come off from the cam groove 19, and the stationary state can be maintained at all times.

In order to reduce the steering torque applied to the steered wheels 10 in order to steer both the front wheels and the rear wheels, an appropriate location in the rear wheel steering force transmission path consisting of the connecting shaft 14, the operating shaft 15, and the input shaft 21 is provided. For example, auxiliary power may be applied to the input shaft 21 by connecting a power cylinder to the input shaft 21, and in addition to the power cylinder for the rear wheels, a power cylinder for the front wheels may be connected to the front wheel steering mechanism. May be incorporated.

Figure 4 shows the shape of the cam groove 19 for steering the rear wheels of the drum 22.
FIG. The cam groove 19 is centered on the center line N1-N
It is constructed by connecting two half cam grooves 11-1.
- Neutral line N2-N2 is a line extending in the circumferential direction of the drum 22 at the point where the diameter of the drum 22 is the smallest. This is the outer line. Each half cam groove 111.19-2 is the first groove part 19
-1A.

19-2A, second groove portions 19-IB, 19-2B, and communication groove portions 19-IC, 19-20 that connect these groove portions.
The half cam grooves 19-1 and 19-2 are symmetrical with respect to the intersection 0. Regarding the half cam groove 19-1 on the right side in FIG. 4, the first groove portion 19-I
A extends in the circumferential direction of the drum from the intersection 0 toward one drum end 22b, and is connected to the terminal end 19-I of the first groove 19-IA.
The second groove part 191B, whose starting end 19'-IBa is smoothly connected to Ab via the communication groove part 19-IC, extends in the circumferential direction of the drum while facing the other drum end 22a, and is connected to the neutral line N2-N2.
The terminal end 19-IBb of the second groove portion 19-IB exceeding
reaches near the drum end 22a.

Since the half cam grooves 19-1 and 19-2 have a point-symmetric shape, the first groove portion 19-IA of these half cam grooves.

Ends 19-IAb of 19-2A, 19'-2A, b mutually and second groove portions 19-IB, ends 19-IB of 19-2B
19-2Bb are located on opposite sides of the neutral line N2-N2, and the first groove portions 19-IA.

19-2A mutual and second groove portion 19-I B, 19-2
B extend in opposite directions in the circumferential direction of the drum. The starting ends of the first grooves 19-IA, 19-2A are connected to each other at the intersection 0, and when the vehicle is traveling straight, in other words, when the steered wheels 10 are in the neutral rotation position, the retainer 24 is connected to the intersection 0. exists in

Further, the terminal ends 19-1B of the second groove portions 19-IB and 19-2B
11. l 9-2 B b is the first groove portion 19-IA
.

The terminal ends 19-IAb and 19'-2Ab of 19-2A are attached to the drum = 12-, so the neutral line N2-N2 passing through the connecting part of the half cam groove 19-1.19'-2 and the communication groove part 19-IC
, 19-2C than the distance 11 from the second groove portion 19-I.
B, termination 19-IBb of 19-2B.

192Bl) and the neutral line N2-N2, 82 is large.

When the drum 22 is rotated by the steering wheel 10,
The engaging element 24 engages with the first groove portion of the half cam groove 19-1 or the half cam groove 19-2 depending on the rotating direction of the drum 22, that is, the steering direction of the steering wheel 10, so that the rotating angle of the tram 22 is large. If so, the retainer 24 will engage with the second groove via the connecting groove.

FIG. 5 shows the horizontal movement distance X of the joint pin 25 of the link member 26 when the rotation angle α of the drum 22 changes from zero to the dog rotation angle. This is a graph showing. In the illustrated example, the engaging element 24 engages with the communication groove when α is 900, and the engaging element 24 returns to the neutral line N2-N2 position at an angle α between 90° and 180°. In other words, the rear wheel steering angle reaches its maximum value when α is 90°, and then returns to zero when α is α1. When the angle becomes higher than that, the rear wheel turning angle increases while the positive and negative sides are reversed. For this reason, the steering direction of the rear wheels 4.4 is reversed when the steered wheels 10 are operated at a small steering angle and when the steering wheel 10 is operated at a large steering angle, so that when the steering wheel 10 is operated at a small steering angle, the rear wheels 4, 4 are turned to the front wheels 1. While steering in the same direction as 1, when operating a large steering angle, the rear wheels 4 and 4 are turned to the front wheels 1 and 4.
It becomes possible to steer in the direction opposite to 1. Furthermore, as mentioned above, since -e2 is larger than pl, the maximum rear wheel turning angle when operating a large steering angle can be made larger than the maximum turning angle of the rear wheels when operating a small steering angle. .

From the above, in the present invention, when the vehicle is running at high speed and a small steering angle operation of the steering wheel 10 is performed, the steering tendency is
When the vehicle is running at low speed and a large steering angle operation of the steered wheels 10 is performed, the inner wheel difference between the front and rear wheels and the turning radius are more effectively reduced. Rear wheel steering operation with good steering or better steering wheel 1o to the right,
This is achieved regardless of the rotation operation to the left.

The ratio between the steering angle of the steered wheels 10 and the rotation angle of the drum 22 can be arbitrarily determined by the speed change rate of the # mechanism by interposing a speed change mechanism in the rear wheel steering force transmission path.

The rear wheel steering operation described above is of course performed by the left and right movement of the tie rods 20 and 20.
．． 20 also moves in the longitudinal direction of the vehicle body as the link member 23 swings. The explanation at this size did not take into account the displacement of the tie rod in the longitudinal direction of the vehicle body, but the length of the tie rod is sufficiently long compared to this displacement, so even if displacement is ignored, the previous explanation will not work. There is no essential difference.

Figures 6 and 7, Figures 8 and 9, and Figures 10 and 1.
Unlike the embodiments shown in FIGS. 2 and 3, FIG. 1 eliminates the need to gradually increase the diameter of the drum from the center in the longitudinal direction of the drum toward both ends. An embodiment is shown in which the diameter of the drum is continuous in the 15-direction of the length of the drum. Therefore, in these embodiments, the drum 42°62.82
and cam grooves 39, 59 for rear wheel steering on the outer circumferential surface of the drum.
．． 79 can be easily formed. drum 42,6
A block member 43.63.83 is slidably fitted on the outer periphery of 2.82, and the block member 43.63.83 has a pin 44° as a retainer that engages with the cam groove 39°59.79. 64.84, so the drum 42.62
When 82 is rotated, the block member 43.63.83 slides in the drum length direction.

In the embodiment shown in FIGS. 6 and 7, teeth 43a are formed on the side surface of the block member 43, and a sector gear 46 meshes with the teeth 43a. The sector gear 46 has a joint pin 45.45 that connects the left and right rear wheel steering tie rods.
The link member 47 is integrally coupled with the main body 46, and the link member 47 can swing left and right about the shaft 46a of the sector gear 46. When the block member 46 slides along the drum 42, the sector gear 46 rotates, which causes the 16-link member 47 to swing left and right, thereby steering the rear wheels.

In the embodiments shown in FIGS. 8 and 9, the pin 64 engages with an elongated hole 66d formed in the first extending portion 66b of the planar cross-shaped link member 66 in the left-right direction. The second extending portion 66c is provided with a joint pin 65.65 to which left and right rear wheel steering tie rods are connected, and the link member 6
6 is slidable around a shaft 66a. When the block member 66 slides along the drum 62, the first extension portion 66
The link member 66 swings while the horizontal displacement between the pin 64 and the pin 64 is absorbed by the elongated hole 66d, and the rear wheels are steered by the second extending portion 66c swinging in the left-right direction.

In the embodiment shown in FIGS. 10 and 11, the joint pin 8 connects the left and right rear wheel steering tie rods to the block member 83.
5.85, and the rear wheels can be directly steered by a block member 86 that slides along the drum 82. Therefore, in this embodiment, the drum 82 is rotatably supported by shaft bearing portions 86a and 86b of a bracket 86 that is fixedly installed on the vehicle body with the drum axis direction being the left and right direction. An input shaft 81 that rotates in conjunction with the steering wheel is supported on the bearing portion 86C of the bracket 86 so as to be rotatable with the longitudinal direction of the vehicle body as the axial direction, and the input shaft 81 and the drum 82 are arranged at right angles to each other in the direction in which the rotational force is transmitted. Bevel gear 87.
88. Since the rotation of the input shaft 81 is transmitted to the drum 82, the block member 860 and the drum 82
The rear wheels are steered by sliding along the .

12 is a diagrammatic diagram showing the apparatus according to the embodiment of FIGS. 2 and 3, and similarly, FIG. 13 is a schematic diagram showing the apparatus according to the embodiment of FIGS. 8 and 9 are diagrammatic diagrams of the apparatus according to FIGS. 8 and 9, respectively; Figure 12, Figure 13,
In FIG. 14, the vehicle body including the bracket 18 is 2
8, 48.68, and the rear wheel steering tie rod is shown as 40.60 in FIGS. 13 and 14.

15 to 28 show modified embodiments of the invention, which, like FIGS. 12, 13, 1 and 14, are shown schematically. Among these modified examples, FIG.
The embodiments shown in FIGS. 8, 21, 24, 25, and 26 have the same basic structure as the embodiment shown in FIG. Figure, Figure 24, 2nd
In Figures 5 and 26, the drums are 122, 132, 14.
2,152°162.172, pins 124, 134, 144 as retainers that engage with the rear wheel steering cam groove
, 154.164°174 is 123
, 133, 143° 153.163.173, and the tie rod for rear wheel steering is 120.130, 140, 15
0,160,170, the car body is 128.138.1
48.158.168.178, the swinging center axes 123a, 133a, 143a of the link members.

153a, 163a, and 173a, respectively. Further, the embodiments shown in FIGS. 16, 19, 22, and 27 have the same basic structure as the embodiment shown in FIG. 13. That is, in FIG. 16, FIG. 19, FIG. 22, and FIG. 27, the drums are 222.242.262.282, and the pins 224, 244, 2 as retainers engage with the cam grooves for steering the rear wheels.
64,284, the members of the block 19 are 223,245,263.285, and the link members integrated with the sector gears 226,246,266.286 are 227,247,267.287, which are tie rods for rear wheel steering. is 220°240,260.2
80, the car body is 228, 248, 268, 288
The center axis of swing of the sector gear and link member is 226
a, 246a.

266a and 286a, respectively. Furthermore, the 17th
The embodiments shown in FIGS. 20, 23, and 28 have the same basic structure as the embodiment shown in FIG. 14. That is, in Figs. 17, 20, 23, and 28, the drum is 32
2,342,362.382, pins 624, 344, 364.3 as retainers that engage with rear wheel steering cam grooves
The block member with 84 is 323, 343, 36
3,383, elongated holes 326d and 346d that engage with the pins.
, 366d, 386d are formed on the link member 326
, 346.36 < 5.386, and the car body is 328.348
．． 368.388, and the swing center axis of the link member is 326
a, 346a, 366a, and 386a, respectively.

In the above modified embodiments, Fig. 15, Fig. 16 = 20-Fig.
Figures 19 and 20 are also shown in Figures 21, 22, and 2.
3, FIG. 26, FIG. 27, and FIG. 28 have commonalities in their respective changed parts.

In the embodiments shown in FIGS. 15, 16, and 17, two tie rods 1 on the left and right are attached to the link members 126, 227, and 326.
20.120.220.220. io, 320 is 1
They are commonly connected by joint pins 125.225.325K.

In the embodiments of FIGS. 18, 19, and 20, the link members 133, 247, 346 as well as other link members 1
39,249.349 are axes 139a, 249a.

349a to the vehicle body 138, 248. ．． 548 and is swingably connected and supported by the tie rod 130.11.2.
40°240.340,340 are connected via tie rod connecting members 167°250,350, and the tie rod connecting members are connected to two link members 133,139,2.
It is supported on both sides at 47°249.346.349. Also in the embodiments shown in FIGS. 21, 22, and 23, the left and right swinging of the link members 133, 247, 346 is transmitted to the tie rod connecting members 137, 250, 350, and the rear wheels are steered. Two tie rods on the left and right 140, 140, 260° 260.3
60,360 is the tie rod connecting part phase 147.270.
370, the tie rod connecting member is cantilevered by the link portions 143, 267, and 366. A bearing member 149, 269.369 is rotatably attached to the vehicle body 148, 268° 368, and a tie rod connecting portion U 147.27 is attached to the bearing portion.
0.370 is slidably inserted and supported, and as the link members 143, 267.366 swing, the bearing member 14
9.269.369 rotates to move the tie rod connecting member left and right.

The embodiment shown in Figure 24 has two tie rods on the left and right, 150°15.
Even if the tie rod connecting member 157 that connects 0 is slidably inserted and supported by two bearing members 159 159 fixedly installed on the vehicle body 158, the swing of the link member 153 causes the tie rod connecting part phase 157 to move left and right. This shows the structure that can be used. In this embodiment, the swing center shaft 153a of the link member 153 is connected and supported by the tip of a swing link member 157 whose base end is a shaft 157a and which is swingably connected to the vehicle body 158, and during the swing movement of the link member 153. The components that are not involved in the horizontal movement of the tie rod connecting member 157 are absorbed by the swinging of the swinging link member 157.

FIG. 25 shows a tie rod connecting member 167 similar to FIG. 24.
The bearing part 169.169 is fixedly installed on the vehicle body 168.
Even if the link member 1 is slidably inserted and supported by
The tie rod connecting member 167 is arranged so that it can be moved left and right by the left and right swinging of the tie rod 63. In this embodiment, the swing center axis 163a of the link member 163 is connected to the vehicle body 1.
68 is engaged with the long hole 168a or the long groove formed in the long groove, and is movable, and components that are not involved in the left-right movement of the tie rod connecting member 167 during the swinging movement of the link member 163 are guided by the long hole 168a or the long groove. It is absorbed by the movement of the swing center shaft 163a.

In the embodiments shown in FIGS. 26, 27, and 28, the tie rod connecting members 177, 290, and 390 are the two left and right bearing members 179, 179 fixedly installed on the vehicle 23.
．． 289, 289, 389.389 is slidably inserted and supported. In these embodiments, the link member 17
3,287.386 and the tie rod connecting member are connected so as to be relatively movable via connecting link members 180, 291, 391, and link members 173, 287° 386
Only the left and right movement component during the swinging motion of the connecting link member 1
73,287.386.

As is clear from the above modified embodiments, various structures are conceivable for the rear wheel steering mechanism including a link member or a block member provided with a retainer that engages with the rear wheel steering cam groove.

As is clear from the above description, according to the present invention, the drum, which is a main component of the rear wheel steering device and has the rear wheel steering cam groove formed on its outer circumferential surface that determines the mode of rear wheel steering operation, is small. This allows the rear wheel steering device to be made more compact overall.
Therefore, the rear wheel steering device can be effectively installed in a limited space of the vehicle body.

24- Also, according to the present invention, the shape of the cam groove is such that the rear wheels are steered in the opposite direction to the front wheels than the maximum rear wheel steering angle during a small steering angle operation in which the rear wheels are steered in the same direction as the front wheels. The maximum rear wheel turning angle during large steering angle operations when the vehicle is being steered at high speeds is set so that the maximum rear wheel turning angle can be set more sharply than the front wheel turning angle during small steering angle operations when the vehicle is running at high speed. While maintaining improved maneuverability by making the rear wheel steering angle larger than the front wheel steering angle during large steering angle operations performed while the vehicle is running at low speed, the inner wheel difference between the front and rear wheels and the turning radius can be reduced. This makes it possible to further improve the maneuverability of the steering wheels.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the general basic structure of the vehicle, Fig. 2 is a perspective view showing the drum peripheral structure, Fig. 3 is a plan view of the main part of Fig. 2, and Fig. 4 is the tram outer circumference showing the shape of the cam groove. development of the surface,
FIG. 5 is a graph showing the relationship between the drum rotation angle and the horizontal horizontal movement distance of the tie rod for rear wheel steering; FIGS. 6, 8, and 10 are perspective views showing devices according to other embodiments; Figure 7,
Figures 9 and 11 are lines 7-7 in Figure 6 and 9-9 in Figure 8.
Sectional views taken along line 11-11 in Fig. 10; Fig. 12 shows Figs. 2 and 3; Fig. 13 shows Figs. 6 and 7;
The figure is a schematic diagram showing each of the embodiments in FIGS. 8 and 9 in line diagrams, and FIGS. 15 to 28 are diagrams showing modified embodiments based on the basic structure of each of the above embodiments. In the drawing, 1 is a front wheel, 4 is a rear wheel, 10 is a steering wheel, 19,
39.59.79 is the cam groove, 20, 40.60 is the tie rod for rear wheel steering, 21 is the input shaft, 22, 42゜62
．． 82 is a drum, 23 is a link member, 24.44°64
．． 84 is a pin as an engaging element, 43, 63, and 83 are sliding block parts. Patent applicant: Honda Motor Co., Ltd. Representative Patent Attorney Yoshi Shimoda - Department Patent Attorney Kunihiko Ohashi

Claims (6)

[Claims] (1) In a vehicle steering system in which the front wheels and the rear wheels are steered by the steering operation of the steered wheels, a drum is connected to an input shaft that rotates in conjunction with the steered wheels, and a drum is connected to the outer peripheral surface of the tram. A steering device for a vehicle, characterized in that a cam groove for steering a rear wheel is formed in the cam groove, and a retainer included in a rear wheel steering mechanism is slidably engaged with the cam groove. (2) The rear wheel steering mechanism includes a swingable link member provided with the retainer, and the diameter of the drum gradually increases from the central portion in the longitudinal direction of the drum toward both ends. A vehicle steering device according to claim 1. (3) The drum has a shape in which the same diameter is continuous in the drum length direction, and the rear wheel steering mechanism includes a block member that is equipped with the retainer and is slidably fitted to the outer periphery of the drum. A vehicle steering system according to claim 1, comprising: a steering system for a vehicle according to claim 1; (4) In a vehicle steering system in which the front wheels and the rear wheels are steered by the steering operation of the steered wheels, a drum is connected to an input shaft that rotates in conjunction with the steered wheels, and a drum is connected to the outer peripheral surface of the drum. A cam groove for steering the rear wheels is formed, and the cam groove is constructed by connecting two half cam grooves having a point-symmetrical shape when the drum is unfolded, and each half cam groove is oriented toward one end of the drum. a first groove extending in the circumferential direction of the drum, and a second groove extending in the circumferential direction of the drum while facing the other drum end, the starting end of which is connected to the terminal end of the first groove via a communication groove. , and the terminal end of the second groove part is separated from the drum outer circumferential line passing through the connecting part of the two half cam grooves by a distance greater than the distance between the connecting groove part and the drum outer circumferential line, and the rear wheel steering is arranged in the said cam groove. A steering device for a vehicle, characterized in that a retainer included in the mechanism is slidably engaged. (5) The rear wheel steering mechanism includes a swingable link member provided with the retainer, and the diameter of the drum gradually increases from the center in the longitudinal direction of the drum toward both ends. A vehicle steering device according to claim 4. (6) The drum has a shape in which equal diameters are continuous in the length direction of the drum, and the rear wheel steering mechanism includes a block portion that is equipped with the retainer and is slidably fitted on the outer periphery of the drum. A vehicle steering system according to claim 4, comprising: