JP2779019B2 - Gear box for four-wheel steering - Google Patents

Description

The present invention relates to a four-wheel steering gearbox used for a four-wheel steering device of a vehicle.

(Prior Art) As such a conventional apparatus, for example, JP-A-64-41
No. 472, Japanese Unexamined Patent Publication No. Sho 64-36572, and the like as shown in FIG.

(Problems to be Solved by the Invention) However, the first device has a double case structure of a case for housing the bevel gear and a housing on the vehicle body side that rotatably supports this case, and is large and heavy.

The second device does not have such a drawback, but is extremely complicated in structure and has a low reliability.

Also, in a four-wheel steering vehicle, alignment adjustment between the front and rear wheels is performed during assembly so that the rear wheels are also in a straight traveling state when the front wheels are in a straight traveling state, and this adjustment is performed at each connection point of a gear box for four-wheel steering. Is performed in a state of being connected. In the case of the device shown in FIG. 3, the pin 201 is screwed into the engagement hole 203, the pin 201 is further screwed, and the inner casing 207 housing the reverse rotation mechanism 205 is moved, so that the bevel gear 21 on the input shaft 209 side is moved.
This is performed in a state where the clutch 215 between the output shaft 213 and the output shaft 213 is engaged. Therefore, the adjusting operation is troublesome. The device shown in FIG. 3 has a double case structure like the first device, and has a complicated structure, a large number of parts, and a large weight. In addition, a large operating force is required, and steering is heavy.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gear box for four-wheel steering, which has a simple structure, is lightweight and compact, has high reliability, and facilitates alignment adjustment of front and rear wheels.

[Constitution of the Invention] (Means for Solving the Problems) A four-wheel steering gear box according to the present invention includes an intermediate gear rotatably supported inside a casing on a vehicle body side, and a first gear and a first gear respectively meshed with the gear. A reversing mechanism including a second gear, a first steering force transmission shaft connected to the first gear, a second steering force transmission shaft rotatably disposed relative to the transmission shaft, and an external operation. Receiving the first and second steering force transmission shafts, the position of connecting the second steering force transmission shaft and the second gear, the first and second steering force transmission shafts, 2
And a connecting member movable to a position for connecting the gears and a position for disconnecting each connection.

(Operation) When the moving member is externally operated to connect the first and second steering force transmission shafts, the steering force is transmitted from one to the other in the same rotational direction. When the second steering force transmission shaft and the second gear are connected, the steering force is transmitted between the first and second transmission shafts by being reversed by the reversing mechanism. When the second steering force transmission shaft is separated from the first transmission shaft and the second gear, transmission of the steering force between the transmission shafts is cut off. When all of these are connected, the alignment between the front and rear wheels can be adjusted.

Since the container is only the casing on the vehicle body side and does not have a double structure, the structure is simple, light and compact.

(Embodiment) An embodiment will be described with reference to FIG. 1 and FIG.

FIG. 2 shows a steering system of a vehicle using this embodiment. Hereinafter, the left and right directions of the vehicle are the left and right directions in FIGS. 1 (a) and 2 and the right side of FIG. 1 (a) corresponds to the front of the vehicle (above FIG. 2). Note that members without numbers are not shown.

First, the steering system shown in FIG. 2 will be described. This is a four-wheel steering (4WS) configuration, which includes a steering wheel 1, a steering column 3, and direction changing mechanisms 5 and 7 using ball screws.
Connecting shaft 9, input shaft 11 (first operating force transmitting shaft), output shaft 13
(Second operating force transmission shaft), gear box 1 of this embodiment
5. Steering gears 17 and 19 using racks and pinions, tie rods 21 and 23, knuckle arms 25 and 27, knuckle spindles 29 and 31, front wheels 33 and 33, rear wheels 35 and 35, and the like.

 Next, the configuration of the embodiment will be described.

The casing 37 is fixed to the vehicle body side, and the casing 37
A pinion gear is provided on the inside of 37 via a pinion shaft 39.
41, 41 (intermediate gears) are rotatably supported. A right side gear 43 (first gear) and a left side gear 45 (second gear) mesh with these gears 41. The left side gear 45 is supported on the casing 37 by a bearing 47. Accordingly, the steering force of the steering wheel 1 input from the input shaft 11 is reversed by the rotation of the pinion gear 41 and transmitted to the left side gear 45. Thus, the reverse rotation mechanism 49 is configured.

The input shaft 11 penetrates through the left side gear 45, and a boss 51 is fixed to the distal end side thereof with a tapered surface 53 and a nut 55. And supported by each other.
Centering of the boss 51 and the shaft 11 is performed by the tapered surface 53, and play is prevented. Also, the left side gear 45
The left end of the boss portion 61 is supported on the outer peripheral side of the boss 51 via a bearing 63 to prevent swinging during rotation. A hollow shaft member 65 is welded to the shaft member 57 to form the output shaft 13. The output shaft 13 is supported on a casing 37 by a bearing 66 at a portion of a shaft member 65.

Splines 67, 69, and 71 are provided on the outer periphery of the shaft member 57, the boss 51, and the boss 61 of the left side gear 45. The coupling sleeve 73 (connecting member) has splines 75 and 77 which can be engaged with these splines 67 to 71 on the left end side and the right end side of the inner circumference, respectively. The left spline 75 is wide and can be engaged simultaneously with the splines 67,69. or,
A gap 79 is provided between the splines 69 and 71 so that the right spline 77 can enter without contact.

The coupling sleeve 73 receives a moving operation as described below, and the position I where the splines 75 and 67 are engaged and the splines 77 and 69 are engaged, and as shown in FIG. , 71, the position III in which the splines 75, 67 are engaged and the splines 77, 71 are engaged, and the position III in which the splines 75 are engaged.
Position IV where 7,69 engages and splines 77,71 engage
And move on.

In the position I, the input shaft 11 and the output shaft 13
The steering force is transmitted from the input shaft 11 to the output shaft 13 in the same rotational direction (forward rotation).

In the position II, the output shaft 13 is connected to the input shaft 11 and the reverse rotation mechanism.
The steering force is not transmitted to the output shaft 13 because it is separated from 49.

In the position III, the output shaft 13 is connected to the left side gear 45 of the reverse rotation mechanism 49 via the sleeve 73. Therefore,
The steering force is reversed by the reversing mechanism 49 from the input shaft 11 and the output shaft
It is transmitted to 13. In this reversing mechanism 49, the pinion shaft 39 is inclined rightward so that the number of teeth of the left side gear 45 is larger than the number of teeth of the right side gear 43. Therefore, the steering force is increased and decelerated by the reversing mechanism 49, and the rotation angle (steering angle) of the output shaft 13 is smaller than that of the input shaft 11.

In position IV, input shaft 11, side gear 45, output shaft
13 are connected via a sleeve 73. In this state, the meshing position of the rack and the pinion of the steering gears 17, 19 is adjusted so that when one between the front wheels 33, 33 and the rear wheels 35, 35 is in the straight traveling state, the other is also in the straight traveling state. An alignment adjustment is performed.

As shown in FIGS. 1 (a) and 1 (b), a fork 83 is slidably engaged with the outer peripheral groove 81 of the coupling sleeve 73. The operating force of the sleeve 73 is formed by the fork 83 and the like. The actuator 85 is moved to each of the above positions via the transmission system.

The actuator 85 has a fail-safe mechanism, and is operated from a driver's seat and driven by pressurized air. That is, the cylinder 87 of the actuator 85 is fixed to the casing 37, and a piston 89 is provided in the cylinder 87. The piston 89 is fixed to an operation rod 91, and the fork 83 is fixed to the operation rod 91 by bolts.

The cylinder 87 is provided with air supply / discharge ports A and B, and the piston 89 moves by supplying compressed air from one of the ports A and B.

In the cylinder 87, fail-safe spring seats 93, 9 are provided.
5 is provided, and a spring 97 is interposed between both spring seats 93 and 95. One spring seat 93 is slidably supported on the inner peripheral surface of the cylinder 87, and the outer peripheral projection 93a is engaged with the step 87a in the cylinder 87 in the position II. The other spring seat 95 is slidably supported on the outer peripheral surface of the collar 99 on the operation rod 91 side.
9a is engaged.

When the pressure air is adjusted and supplied from the port A in the state of the position II, the piston 89 moves to the left, and is moved through the operation rod 91 and the fork 83 to be operated by the sleeve 73.
Is position I. Similarly, when the pressure air is adjusted and supplied from the port B in the state of the position II, the piston 89 moves to the right, the moving force is operated via the operation rod 91 and the fork 83, and the sleeve 73 is in the position III.

As shown in FIG. 1 (b), the position is
Three positioning mechanisms 101, 103, and 105 for I, II, and III are mounted at different positions in the axial direction, and a check ball of each of the mechanisms 101 to 105 is provided at each position with a recess 107 provided on the operating rod 91. And positioning is performed. In FIG. 1A, the check ball of the mechanism 103 is engaged with the concave portion 107 at the position II. Also, each mechanism 101-10
Reference numeral 5 also functions as a position switch, and the switch is activated by the engagement operation of the check ball, and the positions I to III are displayed on the driver's seat.

To set position IV for alignment adjustment,
Loosen the nut 111 on the left end of the operating rod 91 by the advance of the sleeve 73 between the positions III and IV, and use the jig to
Is pressed to the right to move the sleeve 73 to the position IV, and the alignment is adjusted while maintaining this state. After the adjustment, the nut 111 is returned to the original position. To overshift to position IV in this way, an actuator
In addition to the positions I to III, one position is added to the position 85 to overshift, or a screw hole for overshift is provided on the right side of the screw hole for the current bolt 84 of the operating rod 91, and the fork 83 is moved to the right. And fix the actuator.
Sleeve 73 is in position IV when 85 is in position III
You may come to.

In addition, even if the pressurized air escapes from the port A or B due to the breakage of the pipe at the position I or the position III, the sleeve 73 is automatically moved to the position by the action of the spring 97 as shown in FIG. Return to II.

Next, the function of the gear box 15 of this embodiment will be described with reference to the function of the steering system shown in FIG.

When the steering wheel 1 is rotated, this rotation causes the input shaft 11 to rotate via the steering column 3, the direction changing mechanism 5, the connecting shaft 9, and the direction changing mechanism 7. This rotation is further performed by the steering gear 17 and the tie rod 21.
Is moved in the vehicle width direction to steer the front wheels 33, 33 left and right via the knuckle arm 25 and the knuckle spindle 29.

At this time, if the gearbox 15 is set to the position I (forward rotation), the output shaft 13 rotates in the same direction as the input shaft 11, and this rotation moves the tie rod 23 in the vehicle width direction by the steering gear 19, and the knuckle arm 27 and knuckle spindle 31
, The rear wheels 35, 35 are steered in the same direction as the front wheels 33, 33 (in phase).

When the gearbox 15 is set to the position II (rear wheel side separation), the rear wheels 35, 35 are separated in a straight running state, and the vehicle enters a two-wheel steering state.

When gearbox 15 is in position III (reverse)
The steering force is transmitted in the reverse direction, and the rear wheels 35, 35 are steered in the opposite direction to the front wheels 33, 33 (opposite phase).

In the in-phase state, the vehicle can move laterally, and can change lanes without a large roll, for example. Further, when turning, cornering force is generated on the front wheels 33, 33 and the rear wheels 35, 35 at the same time, so that extremely stable turning is possible.

When the steering force to the rear wheels is cut off, the vehicle enters a normal two-wheel steering state.

When the vehicle is in the opposite phase, the turning performance of the vehicle is improved. For example, a vehicle with good turning performance can be provided even with a long wheelbase.
In addition, the minimum turning radius is reduced, and steering in a narrow place such as a garage is facilitated.

As described above, since the gear box 15 has a single structure in which the container has only the casing 37, the number of parts is small, the structure is simple, and the weight is compact. In addition, the bearing between the cases, which is necessary in the conventional double case, is not required, and the supporting and wear parts are reduced accordingly, and the support is assured, and the durability and reliability are improved. In addition, in switching the position, in the conventional example shown in FIG. 3, the reversing mechanism 205 had to be moved together with the inner casing 207, whereas only the coupling sleeve 73 had to be moved. Is very small. Therefore, the size of the actuator 85 can be reduced. Further, the switching by the coupling sleeve 73 is light in operation force and is not easily affected by vibrations in this way, so that the position can be switched reliably. In addition, unlike the conventional example shown in FIG. 3, the steering resistance is substantially constant because the mass of the steering system does not change between forward rotation and reverse rotation.
The steering is light because it does not rotate. Each bearing 47,59,6
3,66 is not durable and has high durability. Further, the alignment of the front and rear wheels can be easily adjusted, so that the structure does not become complicated.

Note that the input shaft 11 may be an output shaft and the output shaft 13 may be an input side.

[Effects of the Invention] The four-wheel steering gear box according to the present invention has a simple structure and is lightweight and compact because the container has a single-layer structure and is switched by a connecting member. Further, the alignment of the front and rear wheels can be easily adjusted, and the durability and reliability are excellent.

[Brief description of the drawings]

FIG. 1 (a) is a sectional view of one embodiment, and FIG. 1 (b) is (a).
2 is a sectional view of a skeleton mechanism showing a steering system using this embodiment, and FIG. 3 is a sectional view of a conventional example. 11 Input shaft (first steering force transmission shaft) 13 Output shaft (second steering force transmission shaft) 37 Casing 41 Pinion gear (intermediate gear) 43 Side gear (first gear) 45 Side gear (second gear) 49 Reverse mechanism 73 Coupling sleeve (connecting member)

──────────────────────────────────────────────────続 き Continuation of the front page (72) Hideo Kato, Inventor 1-chome, 1-chome, Ageo-shi, Saitama Nissan Diesel Kogyo Co., Ltd. (56) References JP-A-1-244980 (JP, A) -161879 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B62D 7/14

Claims (1)

(57) [Claims] An intermediate gear rotatably supported inside a casing on a vehicle body side and a first gear engaged with the intermediate gear.
A reversing mechanism including a first gear and a second gear; a first steering force transmission shaft connected to the first gear; a second steering force transmission shaft rotatably disposed relative to the transmission shaft; A position connecting the first and second steering force transmission shafts in response to the operation, a position connecting the second steering force transmission shaft and the second gear, and a position connecting the first and second steering force transmission shafts. A position for connecting the second gear,
A four-wheel steering gear box, comprising: a connecting member movable to a position at which each connection is disconnected.