JPS619377A - Steering gear for front/rear wheels - Google Patents

Abstract

PURPOSE:To perform automatic alignment, by engaging an eccentric shaft and a joint member slidably with a taper engaging part. CONSTITUTION:An eccentric shaft 22 installed in the rear end of an input shaft 20 in a rear wheel steering system is slidablye engaged with a joint member 40 which connectedly supports tie rods for rear wheel use at both sides. That is to say, the eccentric shaft 22 and the joint member 40 are engaged with each other through a taper engaging part 47, while a preload device 26, energizing the input shaft 20 in a direction toward the joint member 40, is installed. In addition, a regulating devie 87 is installed in the rear of the central part of the joint member 40. This regulating device 8 consists of a guide member 80 set up between holders 50 of the joint member 40, a roller 85 and an adjusting bolt 83.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a steering device for front and rear wheels of a vehicle.

(Prior art) As one of the four-wheel steering systems for vehicles, the present applicant has filed a patent application filed in 1983.
-127188 (Japanese Unexamined Patent Publication No. 58-30889). In this steering system, an eccentric shaft installed at the rear end of the input shaft of the rear wheel steering system, which rotates in conjunction with the steering wheel, and a joint member that connects and supports the left and right rear wheel tie rods are slidably engaged. However, the joint member can only be moved in the left-right direction.

(Problems to be Solved by the Invention) According to such a steering system, since the circumference of the eccentric shaft is directly engaged with the joint member, precision is required for centering, and clearance in the radial direction is generated particularly at the retaining part. There is a technical issue that is difficult to avoid.

The present invention has been made in order to solve the technical problems in the above-mentioned steering system, and its purpose is to realize automatic centering between the eccentric shaft and the joint member, and to improve the relationship between the eccentric shaft and the joint member. It is an object of the present invention to provide a steering device for front and rear wheels that prevents the occurrence of clearance at a joint portion and also prevents rearward deflection of a joint member.

(Means for Solving the Problems) Therefore, the present invention provides an eccentric shaft (22) provided at the rear end of an input shaft (20) of a rear wheel steering system that rotates in conjunction with a steering wheel;
Left and right rear wheel tie rods (15), (15) are connected and supported, and the front and rear wheels are slidably engaged with a joint member (40) supported by the vehicle body so as to be horizontally movable in the left and right direction. In the steering device, the eccentric shaft (22) and the joint member (40) are engaged with each other at a tapered engagement portion (47), and the input shaft (20) is urged toward the joint member (40). Preload means (82), (1f
12), and a regulating means (87) is further provided at the rear of the central portion of the joint member (40).

Specifically, the regulating means (87) includes a guide member (80) disposed between the joint member (40) and its holder (5o), and an axis interposed between the guide member and the joint member that is horizontal. It consists of a roller (85)... and an adjustment bolt (83) that presses against a guide member that is screwed into the holder from the rear.

(Function) Since the eccentric shaft (22) and the joint member (4o) are slidably engaged at the tapered engagement portion (47) in this way,
Automatic centering can be performed by the centripetal action of the tapered engagement part (47), and the input shaft (2o) is connected to the joint member (40).
) preloading means (62), (IE12)
Since the tapered engaging portion (47) is provided, its pressing force causes
In addition, since the regulating means (87) is provided at the rear of the center of the joint shaft member (40), the joint can be kept properly engaged at all times by the pressing force of the preload means (82) and (182). It is possible to prevent the member (40) from deflecting backward, and improve responsiveness.
Be careful.

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

FIG. 1 is a cross-sectional view of a steering angle function generation mechanism of a rear wheel steering system showing the main part of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II, and FIG. 7 is a schematic perspective view of the entire steering system. It is a diagram.

As shown in Figure 7, the support shaft (2) of the handle (1) is built into a rack and pinion gearbox (3), and tie rods (5) are connected to both ends of the rack shaft (4). and the front wheels (7), (7) are attached to the tie rods (5), (5,).
The knuckle arms (B) and (B) supporting the are connected,
As is known, the front wheels (?), (7) are steered in the steering direction of the steering wheel (1).

The pinion shaft (
8) is connected to a long linkage shaft (
10) are connected, and a universal joint (10) is connected to the rear end of the shaft (lO).
1), an input shaft (20) of a rear wheel steering system is connected thereto. As shown in FIG. 1, a flange (21) is formed at the rear end of this input shaft (20), and an eccentric shaft (22) is provided to protrude from this flange (21). The base of this eccentric shaft (22) is formed into a male tapered portion (23).

On the eccentric shaft (22), there is a pinion (31) at the front.
A cylindrical member (30) integrally equipped with a circular eccentric cam (32) at the rear thereof is rotatably fitted thereinto. That is, the inner periphery of the pinion (31) of the cylindrical member (30) is formed into an acid tapered portion (33),
A pole (24)... is provided between the male taper portion (23).
In addition to constructing an angular bearing by interposing
A roller (25) is interposed between the inner periphery of the eccentric cam (32) and the tip of the eccentric shaft (22).

On the other hand, as shown in Fig. 7, the tie rods (15) and (15) connected to the knuckle arms (113) and (1B) supporting the rear wheels (17) and (17) are ball joints (LA), respectively.
, (14) are connected to both ends of the joint shaft (30). As shown in FIG. 1, a fixed member (41) is provided at the center of the joint shaft (40). That is, the member to be secured (41) is fixed and integrated at the center of the joint shaft (40) with two bolts (49) from the lower rear as shown in FIG. The shaft (40) has two vertical walls (40) on the left and right that protrude forward.
3), Acid tapered surface facing forward on the opposite surface of (43) (
44), (44) are formed.

And on the eccentric cam (32) there is a pole (35)...
The engaging member (36) is installed with the eccentric cam (32
) is equipped with a contact type angular bearing. The left and right vertical walls (37), (37) of this engaging member (36)
) Male tapered surface (38) facing rearward on the side of (38
) to form. These two male tapered surfaces (38), (38)
There are stopper protrusions (39) and (3B) on the upper and lower ends of the
, (39) , (39) are prominent.

Furthermore, when the engaging member (36) and the engaged member (41) are assembled together, both the left and right tapered surfaces (3B), (4
4), (38), (44), as shown in FIG. ... respectively.

The above input shaft (20) and joint shaft (40) are connected to a box (51) at the center and pipes (52) at the front and left and right sides.
), (53), holder (5) integrally formed with (53)
0). That is, the box (5) of the holder (50)
1) With the member to be secured (41) facing inside, insert the joint shaft (
40), left and right pipes (53), and metal bearings (54) inside (53).

(The engaging member (50) is supported so as to be horizontally slidable horizontally.
36) to the engaged member (41) and the roller (46)...
, (4B), etc., and the input shaft (20) is rotatably supported in the front pipe (60).

Furthermore, an internal ring gear (70) with which the pinion (31) meshes and revolves is provided in the inner part of the box (51) when viewed from the rear, the thrust being restricted by a snap ring (78). This ring gear (70) consists of two ring gears (71) and (72) stacked in the axial direction, and one gear (71) is connected to the box (51) by a bolt (78).
Upper and lower steps (73) are formed on the negative side of the other gear (72), and a box (
Adjustment pole screwed together from the top and bottom of 51)) (7?)
, (7?) to the stepped portions (73) and (73). Also both ring gears (71).

(72) is provided with a large number (six in Fig. 4) of four parts (74) that penetrate in the axial direction.
) in which an S-shaped spring (75) as shown in Fig. 5 is placed around Mc:M! I Lr1iIJThl+1: (llly
, fya (72) L-Y'JEo6゜ 1 manpower axis (
Specifically, the ring (20) is supported by interposing a pole (2B) on the front part of the rear end flange (2).
7), equipped with a contact type angular bearing, and lightly fit the ring (27) onto the inner periphery of the base end of the pipe (52). Then, place the thrust washer (61) on the front end of the ring (27) and insert the sleeve (
80) are screwed together and inserted, and the rear end of the sleeve (60) abuts against the washer (61). A space is provided between the sleeve (60) and the input shaft (20), a coil spring (62) is placed in this space, and the sea is regulated by a step (83) at the middle part of the inner circumference of the sleeve (60). A spring (62) is compressed between the ring (84) and the washer (61) to preload the ring (27) to bias it rearward. Furthermore, a lock nut (fi5) is screwed onto the sleeve (60). Further, a roller bearing (66) is interposed between the front end of the sleeve (60) and the input shaft (20), and a seal cap (67) is placed on the roller bearing (66).

In the above, the second member is provided on the rear surface of the engaged member (41).
As shown in the figure, a vertical surface (47) is formed and a box (
A boss (56) is formed on the opposite surface of the cover (55), which is closed by tightening the opening of (51)) (59)...
A guide groove (57) is formed in the left-right direction in the boss (58), and a guide bar (80) having a vertical surface (81) facing the vertical surface (47) is inserted into this groove (57). The stopper protrusions (82) are located at the left and right ends of this vertical surface (81).
), (82) are projected. The guide bar (80) is screwed onto the cover (55) from the rear (two wooden poles on the left and right)
The rain vertical surface (
47) and (81) are interposed with a roller (85) whose axis is perpendicular and which is held by a retainer (84).

Further, a plate spring (86) is interposed between the guide bar (8o) and the cover (55) to preload the guide bar (80) so as to always urge it forward.

In this way, the holder (50) is arranged with the input shaft (20) aligned with the left and right center line of the vehicle body, and the left and right pipes (53)
, (53) with soft mounting rubber (91), (91
) (92), (f32)
support. In addition, compact rubber boots (94) are made by tightening the left and right ball joints (14) and (+4) to the end of the pipe (53) and the end of the tie rod (15) with bands, respectively.
Cover with (94).

In the above steering system settings, the eccentric shaft (22) is connected to the input shaft (2
0), for example, vertically downward as shown in Figure 3, and when steering the front wheels (?) and (?) to the right, the eccentric shaft (22) will rotate clockwise in Figure 3. Set the crank to rotate. Here, the pinion (31) meshes with the lowest part of the ring gear (70) as shown in FIG. 4, and the top (34) of the eccentric cam (32) faces vertically downward as shown in FIG.

First, the rotation direction of the pinion (31) due to crank rotation from the initial position of the eccentric shaft (22) is opposite to the rotation direction of the eccentric shaft (22) when the revolution angle is less than a predetermined angle. Since the horizontal movement directions of the eccentric shaft (22) and the rear portion (34) of the eccentric cam (32) are opposite to each other, the resultant displacement amount, which is the difference between them, is small.

Therefore, the joint shaft (40) that engages with the eccentric cam (32)
) because the maximum left-right displacement of the rear wheel (1?) is small.
.

The maximum steering angle when (17) is steered in the same direction as the front wheels (7), (7) is small.

Furthermore, if the revolution angle of the pinion (31) exceeds a predetermined angle,
An eccentric shaft (22) and an eccentric cam (3) relative to the input shaft (20)
2), the direction of movement to the left and right is the same as that of the top (34) of The maximum steering angle of the wheels (17) and (1?) in the direction opposite to that of the front wheels (7) and (7) increases.

Then, the eccentric cam (32) and the joint shaft (40) are slidably engaged with each other at the tapered engagement portion (47), that is, the eccentric cam (32) is slidably engaged with the joint shaft (40).
) with a pole (35) interposed between the male taper member (3
8), and the joint shaft (40) is equipped with left and right acid taper members (43), (43) integrated, and both male and female tapers (3B), (44), (3B), (44) are installed. Because rollers (46)..., (4B)... were inserted between them,
Friction can be minimized, and automatic centering can be achieved by the centripetal action of the tapered engagement.

Moreover, the sleeve (60) can be adjusted forward and backward within the front pipe (52) of the holder (50).
60), the input shaft (20) via the washer (61) and angular pole bearings (21(), (2?)
The position of the locking nut (85) can be adjusted, and the engagement relationship can be adjusted.

Furthermore, the preload spring (62) presses the input shaft (20) backward through the washer (61) and the angular pole bearings (2B) (2?), which prevents play in the tapered engagement portion (47). This can be prevented and the engaged state can be maintained well even during long-term use. That is, due to the pressing force of the spring (62), the angular pole bearings (2B), (2?), (24), (30)
, (35), (3El) Since the clearance of the tapered engaging portion (47) can be maintained at zero in both the radial and thrust directions, it is possible to prevent play between each component and to guarantee the set steering angle.

Thereafter, a regulating means (87) is provided at the rear of the center of the joint shaft (40), that is, the joint shaft (40) is
0) A guide bar (80) is provided at the rear of the center, a roller (85) is interposed between this and the joint shaft (40), and the joint shaft (40) is connected to a plate spring (86).
Since the elastic force of the joint shaft (40) is biased forward, it is possible to prevent the joint shaft (40) from deflecting backward due to the bias of the preload spring (62).
It is also possible to reduce sliding friction and improve responsiveness. Furthermore, even if the span of the metal bearings (54), (54) that pivotally support the joint shaft (40) is widened, the rigidity of the joint shaft (40) can be ensured, and the metal bearings (54), (54) may wear out. can be prevented.

Next, another embodiment of the adjustment and preload structure of the input shaft (20) will be described based on FIG. 6.

A pipe (152) that pivotally supports the input shaft (20) is formed long in the front, and a roller bearing (IBEI) is interposed between the rear part of the input shaft (20) and the pipe (152).
) A regulating means and a preload means are constructed between the front part and the pipe (152).

That is, the front part of the input shaft (20) is formed into a small diameter part (121), and the angular pole bearing (
The inner ring (124) of the outer ring (123) is press-fitted into the outer ring (125).
) into the large diameter part (159) at the front of the pipe (152). Then, the thrust washer (161) is placed on the front surface of the outer ring (125), and the sleeve (180) is screwed and inserted into the large diameter portion (1513) of the pipe.
0) Push the rear end against the washer (tel). A coil spring (162) is inserted into the space between the sleeve (181) and the input shaft (20), and the spring (182) is inserted between the washer (161) and the fuser (+64) provided on the inner periphery of the front part of the sleeve (tea). Shrink. Furthermore, the sleeve (ll
screw the lock nut (165) onto the

In addition, in the embodiment, a so-called asymmetric function type steering device was described in which the maximum steering angle of the rear wheels is larger when the front wheels are out of phase than when they are in the same phase. The present invention also includes a symmetrical function type steering device that is adapted to match the steering device.

(Effects of the Invention) As described below, according to the front and rear wheel steering device of the present invention, in particular, the eccentric shaft and the joint member that moves horizontally in the left and right direction are slidably engaged by the tapered engagement portion. In addition to providing a preload means for biasing the input shaft toward the joint member, a regulating means for preventing rearward deflection at the center of the joint member is provided, thereby automatically aligning the eccentric shaft and the joint member. The steering angle can be maintained with high precision.
Moreover, it is possible to constantly optimize the taper engagement part, prevent the occurrence of looseness due to long-term use, guarantee the set steering angle, and increase the rigidity of the joint member (87).
is a regulatory measure.

It is highly practical, as it can ensure good responsiveness and reduce the sliding friction of the joint member.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a steering angle function generation mechanism of a rear wheel steering system showing the main part of the present invention, FIG. 2 is a cross-sectional view taken along line IT-11 in FIG. 1, and FIG. 3 is a cross-sectional view taken along line IT-11 in FIG. M-line sectional view, Figure 4 is Figure 1 I
5 is a sectional view taken along the line v-v in FIG. 4, and FIG. 6 is a sectional view of main parts showing another embodiment of the adjustment and preload structure.
FIG. 7 is a schematic perspective view of the entire steering system.

Claims (2)

[Claims] (1) The eccentric shaft installed at the rear end of the input shaft of the rear wheel steering system that rotates in conjunction with the steering wheel connects and supports the left and right rear wheel tie rods, and is supported on the vehicle body so that it can be horizontally moved in the left and right direction. In a vehicle steering system, the eccentric shaft and the joint member are slidably engaged with each other so that both the front wheels and the rear wheels are steered by steering operation of a steering wheel. and a preload means for biasing the input shaft in the direction of the joint member, and a regulating means for preventing rearward deflection of the joint member at the rear of the center portion of the joint member. A steering device for the front and rear wheels. (2) In claim 1, the regulating means includes a guide member disposed between the joint member and its holder, and a roller whose axis is perpendicular, which is interposed between the guide member and the joint member. and an adjustment bolt that is screwed into the holder from the rear and pressed against the guide member.