JP2777229B2 - 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) A conventional apparatus of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 64-4147.
No. 2 or JP-A-64-36572. Thus, four-wheel steering can be performed by these.

(Problems to be Solved by the Invention) However, the former has a double case structure of a case for accommodating a bevel gear and a housing for rotatably supporting the case on the vehicle body side, and the device is large and causes an increase in weight. There is a problem.

The latter does not have such disadvantages, but has a very complicated structure and has a problem in operation reliability.

Therefore, an object of the present invention is to provide a steering gear box which has a simple structure, is lightweight and compact, and has high reliability.

[Structure of the Invention] (Means for Solving the Problems) A steering gear box according to the present invention has an intermediate gear rotatably supported inside a casing on the vehicle body side inside a casing on the vehicle body side, and meshes with this gear, respectively. Reversing mechanism including the first and second gears, a first steering force transmission shaft connected to the first gear, and a second steering force transmission shaft arranged to be rotatable relative to the transmission shaft. Can be moved to a position where the first and second steering force transmission shafts are connected to each other in response to an external operation, a position where the second steering force transmission shaft is connected to the second gear, and a position where each connection is disconnected. And a simple connecting member.

(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. Further, when the second steering force transmitting shaft and the second gear are connected, the steering force is transmitted in a reverse direction between the first and second steering force transmitting shafts by the reversing mechanism. When the second steering force transmission shaft is separated from the first steering force transmission shaft and the second gear, transmission of the steering force between the first and second steering force transmission shafts is interrupted.

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

(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 are the left and right directions in the respective drawings, and the right side in FIG. 1 corresponds to the front of the vehicle (upward in FIG. 2). The members and the like without numbers are not shown.

First, the steering system shown in FIG. 2 will be described. This is a four-wheel steering (4WS) configuration, in which a steering wheel, a steering column 3, direction changing mechanisms 5 and 7 using ball screws, a connecting shaft 9, a first steering force transmitting shaft 11, and a second steering force transmitting shaft 1 are provided.
3, gear box 15 of this embodiment, steering gears 17, 19 by rack and pinion, tie rods 21, 23, knuckle arms 25, 27, knuckle pindles 29, 31, front wheels 33, 33,
It is composed of rear wheels 35, 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. Each side gear 43, 45 is casing by bearing 47, 49 respectively.
It is rotatably supported on 37. Therefore, side gear 4
The rotation input from one of 3, 45 is reversed by the rotation of pinion gear 41 and transmitted to the other. Thus, the reversing mechanism
51 are configured.

The first transmission shaft 11 passes through the side gears 43 and 45, is spline-connected to the right side gear 43, and is rotatably supported by the left side gear 45 via a needle bearing 53. On the left side, a boss 55 is spline-connected and positioned in the axial direction by a retaining ring 57, and the tip end engages and supports the concave portion of the shaft member 59 via the needle bearing 61 on the second transmission shaft 13 side. I have. Shaft member 59
Is connected to a hollow shaft member 63 by a pin 65, and the second transmission shaft
Make up 13. A boss 67 is spline-connected to the left side gear 45 and is positioned by a retaining ring 69.

A coupling sleeve 71 is connected to the outer periphery of the shaft member 59 by a spline 73 so as to be movable in the axial direction. A spline 79 that can be engaged with splines 75 and 77 provided on the outer periphery of each of the bosses 55 and 67 is provided on the inner periphery of the right end of the sleeve 71. When the sleeve 71 is moved, the spline 79 and the spline 75 are engaged and connected to the boss 55, as shown in FIG.
The spline 79 is moved to a position III where the spline 79 is engaged with the spline 77 and is connected to the boss 67, and a position II where the spline 79 is not engaged with any of the members 5 and 77.

In the position I, the first transmission shaft 11 is connected to the second transmission shaft 13 via the sleeve 71, so that the steering force is transmitted from the first transmission shaft 11 to the second transmission shaft in the same rotational direction (forward rotation). It is transmitted to 13.

In the position II, the second transmission shaft 13 is connected to the first transmission shaft 11
The steering force is not transmitted to the second transmission shaft 13 because it is separated from the reverse rotation mechanism 51.

In the position III, the second transmission shaft 13 is connected to the left side gear 45 of the reversing mechanism 51 via the sleeve 71. Therefore, the steering force is reversed from the first transmission shaft 11 via the reverse rotation mechanism 51 and transmitted to the second transmission shaft 13. In the reversing mechanism 51, the pinion gear 41 is tilted to the right to
The number of teeth of 45 is larger than the number of teeth of the right side gear 43.
Accordingly, the steering force is reduced by increasing the torque by the reversing mechanism 51 and the rotation angle (steering angle) of the second transmission shaft 13 becomes smaller than the rotation angle of the first transmission shaft 11.

A fork 83 is slidably engaged with the outer peripheral groove 81 of the coupling sleeve 71, and the fork 83 constitutes a part of a transmission system of an operating force of an actuator that moves the sleeve 71 as described above. This actuator is operated from the driver's seat.

Next, the function 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 transmission 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 further moves the tie rod 21 in the vehicle width direction by the steering gear 17, and the knuckle arm 25 and the knuckle spindle
The front wheels 33 are steered left and right via 29.

At this time, if the gearbox 15 is set to the position I (forward rotation), the transmission shaft 13 rotates in the same direction as the transmission 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 wheel 35 is steered in the same direction as the front wheel 33. (In-phase) When the gearbox 15 is set to the position II (interruption), the steering force to the rear wheels is interrupted.

When gearbox 15 is in position III (reverse)
The steering force is transmitted in the reverse direction to the rear wheels, and the rear wheels 35 are steered in the opposite direction to the front wheels 33. (Out-of-phase) In the same-phase state, the vehicle can skid and the vehicle can change lanes without a large roll. Further, when turning, a cornering force is generated in the front wheel 33 and the rear wheel 35 at the same time, so that extremely stable turning is possible.

When the vehicle is in the opposite phase, the turning performance of the vehicle is improved. For example, a vehicle having good rotation can be obtained even with a long wheelbase.
Further, the minimum turning radius is reduced, and operation in a narrow place such as a garage is facilitated.

When the steering force to the rear wheels is cut off, the normal front wheels 2
The wheel steering state is set.

As described above, since the gear box 15 has a single structure including only the casing 37 unlike the conventional example, the number of parts is small, the structure is simple, and the weight is low. Further, only the coupling sleeve 71 needs to be moved in the switching operation.
Therefore, the required moving operation force is very small,
The actuator can be downsized. In addition, the switching by the coupling sleeve 71 is not only in this manner, the operation force is light, but also the switching is reliable without being affected by the vibration. In addition, the steering resistance is substantially constant during forward rotation because the mass of the steering system does not change from that during reverse rotation, and steering is light because the casing 37 is not rotated.
The bearings 47, 49, 53, 61 do not receive excessive force, so they have high durability.

The transmission shaft 13 may be on the input side of the steering force, and the transmission shaft 11 may be on the output side.

FIG. 3 shows another embodiment. Since the basic configuration is the same, the same reference numerals are given and the detailed description is omitted.

In this embodiment, an actuator 85 for operating the fork 83 is embodied. The actuator 85 has a fail-safe mechanism and is driven by pressurized air. That is, the actuator
The 85 cylinder 87 is fixed to the casing 37, and a piston 89 is provided in the cylinder 87. Piston 89
Is fixed to an operation rod 91, and the fork 83 is fixed to the operation rod 91.

The cylinder 87 is provided with air supply / discharge ports A and B, and the piston 789 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 9 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 on the inner surface of the cylinder 87 in the neutral state of the position II. The other spring seat 9
5 is slidably supported on the outer peripheral surface of the collar 97 on the operation rod 91 side, and the inner peripheral projection 95a is engaged with the step 97a on the outer surface of the collar 97 at the position II.

When the pressure air is adjusted and supplied from the port A in the state of the position II in FIG. 3, the piston is moved as shown in FIG.
89 moves, and the sleeve 71 becomes the position I via the operation rod 91 and the fork 83. When pressure air is adjusted and supplied from port B, piston 89 moves as shown in FIG.
The sleeve 71 is at a position corresponding to the position III via the operation rod 91 and the fork 83. In the position III, the positioning is performed by the check ball 98 and the concave portion 100. It should be noted that also in the positions I and II, the positioning is performed by the not-shown check ball and the concave portion 100. Position IV connects shaft member 59, bosses 55 and 67 and uses them only during assembly.
This is to adjust the positions of the front wheel and the rear wheel.

Also, even if the compressed air escapes from the port A or B due to the breakage of the pipe, the spring 99 returns to the state shown in FIGS. 4 and 5 from the state shown in FIGS. .

In addition, this embodiment has the following features. First,
The tightening of the steering transmission shaft 11 is performed by a taper surface 101 and a nut 103 instead of the washer 57 in FIG. Therefore, play is reduced. Further, the casing 37 is changed from three pieces to two pieces, and the side gear 45 and the boss 67 are integrally formed. Therefore, the number of parts is small, and the number of parts is reduced. The sleeve 71 has a large diameter to reduce backlash.

[Effects of the Invention] As described above, the gear box of the present invention has a simple structure, is lightweight, and is compact because the container has a single structure and switching is performed by the coupling sleeve. Also, the operation reliability is excellent.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment, FIG. 2 is a skeleton mechanism diagram showing a steering system using this embodiment, FIG. 3 is a cross-sectional view of another embodiment, FIG. 4 and FIG. FIG. 11 First steering force transmitting shaft 13 Second steering force transmitting shaft 37 Casing 41 Pinion gear (intermediate gear) 43 Side gear (first gear) 45 Side gear (second gear) Gears) 51 Reverse rotation mechanism 71 Coupling sleeve (connecting member)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-244980 (JP, A) JP-A-1-161879 (JP, U) (58) Fields investigated (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 connecting member movable to a position for connecting the first and second steering force transmitting shafts in response to the operation, a position for connecting the second steering force transmitting shaft and the second gear, and a position for disconnecting each connection. And a gear box for four-wheel steering.