JPH0746622Y2 - Steering device for motorcycles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a steering device for a motorcycle or the like, and more particularly to a steering shaft support structure in a head pipe.

[Prior Art] Steering wheels (generally the front wheels) of motorcycles and the like are rotatably supported on the lower end of a front fork, and the front fork is a steering device via two brackets attached to the upper part. It is held by the steering shaft. The steering device rotatably supports a steering shaft in a head pipe in front of a vehicle body frame via bearings, and has upper and lower shaft ends protruding from the head pipe.
One bracket is attached to each of the upper and lower ends of the steering shaft. The steering handle is attached to an upper (upper) bracket of the above brackets, and the steering shaft, the front fork and the steered wheels are rotated left and right with respect to the head pipe by operating the steering handle.

In the conventional steering device, the steering shaft is supported in the head pipe by a structure as shown in FIG. 3 (the drawing is shown, for example, in Japanese Utility Model Publication No. 61-73493). That is, tapered roller bearings are provided on the lower and upper parts of the head pipe 10 '.
41 and 42 are arranged facing each other (the direction is opposite), and the steering shaft 20 'is inserted inside and the positions of the steering shaft 20' and bearings 41 and 42 are fixed by tightening the nut 27 '. Has been done. Due to the structure of the bearing mounting portion of the head pipe 10 'and the steering shaft 20', when the nut 27 'is tightened, the tightening force is the inner ring 42a / outer ring 42b of the bearing 42, the head pipe 10'.
Since the bearings 41 and 42 act in series from the outer ring 41b of the bearing 41 to the inner ring 41a thereof, the bearings 41 and 42 are mounted in a state with no clearance (bearing clearance). An under bracket 31 'for holding a front fork (not shown) is fixed to the lower end portion of the steering shaft 20', and an upper bracket 32 '.
Is attached to the upper end portion 20'b of the steering shaft 20 'which is one step thinner than the threaded portion 20'a of the nut 27', and the washer for preventing rotation of the nut 27 '.
It is inserted by inserting 33 and is fixed by a fixing nut 34 '.

As the bearings 41 and 42 between the steering shaft 20 'and the head pipe 10', the tapered roller bearings are used as described above.
This is because the thrust load and radial load applied to 42 are large. Axial forces and moments act on the steering shaft 20 'through the front forks as the steered wheels move up and down.
This is because the above-mentioned thrust / radial load is considerably large, and particularly in racing motorcycles, it cannot withstand long-term use in a commonly used deep groove ball bearing.

[Problems to be Solved by the Invention] In the conventional steering device (FIG. 3) described above, a nut is used to mount the tapered roller bearings 41 and 42.
27 'must be tightened with the correct tightening torque. That is, if the tightening torque is below the appropriate value,
The bearing clearance of the two tapered roller bearings 41 and 42 becomes large, which causes the steering shaft 20 'to rattle up, down, left, and right. When the tightening torque exceeds the appropriate value, the rotational resistance of the bearings 41, 42 increases, and the steering wheel is operated. Becomes heavy. Therefore, it is necessary to strictly control the tightening torque of the nut 27 ', and it takes a considerable time to assemble the steering device.

In addition, after tightening, the upper bracket 32 'is inserted into the upper end 20'b of the steering shaft 20' and the fixing nut 34 'is screwed into the upper bracket 32' so that the tightened state of the nut 27 'does not change. It is necessary to devise it. That is, as shown in FIG. 3, by providing a step above the threaded portion 20'a of the nut 27 'to make the upper end portion 20'b of the steering shaft one step thinner and then inserting the upper bracket 32' therein. , Fixing nut 3
Even if the 4'is tightened, the upper bracket 32 '
It is necessary not to press 7'and to install a washer 33 for preventing rotation on the nut 27 'which tends to loosen due to delicate tightening torque.

[Object of the Invention] The present invention has been made in order to solve the above-mentioned problems, and has sufficient durability against a load acting on the steering shaft, has a simple structure, has a small number of parts, and can be assembled. It is intended to provide an easy steering device for a motorcycle or the like.

[Means for Solving the Problems] In order to achieve the above object, a steering device according to the present invention is provided with at least two angular balls as part or all of a bearing interposed between a steering shaft and a head pipe. The bearings are arranged facing each other, and only the inner rings of all the above bearings are axially fastened to the steering shaft by nuts that are screwed into the steering shaft, and fixed to the steering shaft. It is a thing.

[Operation] In the steering device of the present invention, since at least two angular ball bearings having a high basic load rating are arranged to face each other between the steering shaft and the head pipe, the radial load acting via the steering shaft and the bidirectional The bearing has sufficient durability against thrust load and can be used for a long period of time.

Further, since only the inner rings of all the bearings are tightened and fixed by the nuts screwed to the steering shaft, the tightening force does not affect the rotation resistance of the bearings or the bearing clearance (play). That is, it is not necessary to manage the tightening torque of the nut.

Further, since the upper bracket is attached to the steering shaft by abutting against the nut, it is not necessary to provide a step on the steering shaft or to attach a nut rotation washer as in the prior art. The upper bracket can be brought into contact with the nut because of the nut tightening torque (tightening force) as described above.
Therefore, even if the upper bracket exerts a force directly on the nut or a force acts on the nut from another via the bracket, it does not affect the rotation resistance of the bearing or the bearing clearance. Absent. Since the upper bracket is brought into contact with the nut, it is not necessary to form a step on the steering shaft for abutting and fixing the upper bracket. Further, since the tightening torque of the nut can be made sufficiently large and the upper bracket contacting with the nut may be attached in any state, no special means for preventing the nut from rotating is required.

[Embodiment] FIG. 1 shows an embodiment of a steering device of the present invention, and is a vertical cross-sectional view (side view) of a head pipe portion of a motorcycle. As shown in the figure, the steering device 1 rotatably supports a hollow steering shaft 20 in a head pipe 10 fixed in front of the vehicle body frames 11 and 12 via bearings 21, 22, 23 and 24. The under bracket 31 is fixed to the lower end portion of the steering shaft 20 by welding, and the upper bracket 32 is fitted and fixed to the upper end portion. An upper portion of a front fork (not shown) is held by these two brackets 31 and 32.

The first feature of this embodiment is that the bearings 21, 22, 23, 24 are all angular contact ball bearings, and two bearings 21, 22 and two bearings 23, 24 are combined below and above the head pipe 10, respectively. It has been arranged. Moreover, in each set, when the inner ring is fixed, the movement of the outer ring in the axial direction is restricted from each other.
22 and 23 and 24 face each other.

The second feature is that the above-mentioned two sets of bearings 21 and 22, and 23 and 24 are the same.
In the middle of the above, the collar 26 is fitted on the steering shaft 20, the nut 27 is screwed from the upper end side of the steering shaft 20, and the inner ring of all the bearings 21, 22, 23, 24 is tightened by tightening the nut 27. It was fixed at 20. Steering shaft as shown
Collar 20a formed on the lower end side of 20, collar 26 and nut 27
Since the respective tip portions of all contact only the inner rings of the bearings 21, 22, 23, 24, and the widths of the inner and outer rings of the bearings 21, 22, 23, 24 are equal, the above tightening force is applied to the bearing 21, It acts axially only on the inner rings of 22, 23, and 24.

Shoulders 10a and 10b formed on the inner surface of the head pipe 10 are in contact with the end faces of the outer races of the bearings 22 and 23 mounted near the center of the steering shaft 20, as in the conventional case (see FIG. 3). Since the dimension between the end surfaces of the shoulder portions 10a and 10b is set slightly shorter than the dimension between the end surfaces of the collar 26, that is, a minus tolerance is set), various types that act on the steering shaft 20 via the brackets 31 and 32. The load of is received by the head pipe 10 as follows (however, the actual load acts as a combination of the following items).

When an axial / upward load is applied to the steering shaft 20:
The collar 20a of the steering shaft 20 pushes the inner ring of the bearing 21 upward → The pushing force acts as a thrust load of the bearing 21 and is transmitted to the outer ring, which further pushes the outer ring of the bearing 22 → The outer ring of the bearing 22 is the head Since the steering shaft 20 is in contact with the shoulder portion 10a of the pipe 10, the above load is applied to the head pipe 10 without the steering shaft 20 moving upward.

When an axial / downward load is applied to the steering shaft 20:
The tip of the nut 27 pushes the inner ring of the bearing 24 downward → The pushing force acts as a thrust load of the bearing 24 and is transmitted to the outer ring, which further pushes the outer ring of the bearing 23 → In the same manner as above Is applied to the head pipe 10 via the shoulder portion 10b, and the steering shaft 20 does not move downward.

When a load or moment perpendicular to the steering shaft 20 acts on the steering shaft 20, the outer peripheral surface of the steering shaft 20 pushes the inner rings of the bearings 21, 22, 23, 24 to the outer side → the pressing force of the bearings 21, 22, 23, 24 Is transmitted to the outer ring as a radial load of → bearings 21, 22, 23,
Since the outer wheels of 24 are in contact with the inner peripheral surface of the head pipe 10, the above load is applied to the head pipe 10 without the steering shaft 20 moving in the front, rear, left and right directions.

The angular contact ball bearings 21, 22, 23, 24 have a larger number of balls than the deep groove ball bearings because of their structure, and they can withstand a large load (that is, have a high basic load rating). The two-wheeled vehicle has a long life even when the above load is large.

Another feature of this embodiment is that the upper bracket 32 is brought into contact with the back surface of the nut 27, fitted into the upper end portion of the steering shaft 20, and fixed by the fixing nut 34. With such a simple structure, the upper bracket 32
The nut 27 can be attached to the bearings 21, 22, 23, 24.
This is because only the inner ring of is tightened and the rotation resistance of each bearing 21, 22, 23, 24 is not affected. Nut 27
No matter how fast you tighten or the upper bracket
Even if you insert 32 and tighten the fixing nut 34,
The rotation of 21, 22, 23, and 24, that is, the rotation of the steering shaft 20 with respect to the head pipe 10 is smooth. Since the nut 34 is screwed on the back surface of the nut 27 with the upper bracket 32 sandwiched between them, which is in a so-called double nut state, a washer for preventing rotation is not required. As described above, the steering device 1 has the advantages that the shape of the upper end of the steering shaft 20 and the mounting structure of the upper bracket 32 are simple, and that torque management is not required when tightening the nut 27 and assembly is easy. .

If angular contact ball bearings 21, 22, 23, 24 having a slight difference in plane between the inner and outer rings are used as the angular contact ball bearings of this embodiment, a part of the tightening force of the nut 27 is used to make the bearings of each set.
It is also possible to apply a preload between 21 and 22 and between 23 and 24 to eliminate the bearing clearance and increase the mounting rigidity of the steering shaft 20. Angular contact ball bearings with a difference in plane are a slight gap (plane difference) between the axial end faces of the two inner rings when the back face combination is used, as is the case with bearings 21 and 22 (same for bearings 23 and 24).
By tightening the nut 27 to eliminate this gap (preload), the balls and the inner ring / outer ring are elastically deformed, and the bearing clearance becomes zero (or negative). The tightening force of the nut 27 that exceeds the preload is such that the bearings 21, 22, 2
Since it acts only on the inner rings of 3 and 24, it is not necessary to control the tightening torque of the nut 27 in this case as well.

Next, another embodiment of the present invention will be described with reference to FIGS. 2 (a) and 2 (b).

The steering device 2a shown in FIG. 2 (a) has a lower angular contact ball bearing in which the upper bearing (23, 24; see FIG. 1) of the first embodiment is replaced by a single deep groove ball bearing 25. 21, 22
The outer ring of the head pipe 10 and the shoulder 10a of the head pipe 10
It is sandwiched by the end plate 13 attached to the lower end of the. In this example, since there is no shoulder (10b) above the head pipe 10 and the outer ring of the bearing 25 is not fixed in the axial direction, only the radial load based on the above-mentioned load acts on the bearing 25, and The lower bearings 21 and 22 bear all the load. When only the radial load is applied, the deep groove ball bearing 25 also has a considerable durability, and therefore it can be said that this steering device 2a also has sufficient practicality.

A large diameter portion 20d is formed in the middle portion of the steering shaft 20 to eliminate the need for the collar (26). The under bracket 31 is also fixed with the fixing nut 35 similarly to the upper bracket 32, but since the under bracket 31 is provided with the protruding end 31a that abuts only the inner ring of the bearing 21, the nut 35 and the nut 27 Is tightened, only the inner rings of the bearings 21, 22 and 25 are axially tightened and fixed to the steering shaft 20.

The steering device 2b shown in FIG. 2 (b) does not include the bearings (22, 23, see FIG. 1) near the center of the head pipe 10 in the first embodiment. These bearings (22,
23) can be omitted because the load is not supported when the axial load is applied to the steering shaft 20 (as described above and) even in the first embodiment. That is, the steering device 2b has a total of only two angular ball bearings 21 and 24, but has the same durability as the device 1 of the first embodiment against the loads of and. However, since the number of bearings is half, it is weak against a load (radial load) based on a moment or the like, and thus is applicable to a relatively small motorcycle or the like. In this example as well, when the nut 27 is tightened, the tightening force acts only on the inner races of the bearings 21 and 24, so management of tightening torque is unnecessary.

By the way, in this steering device 2b as well, the bearings 21 and 24 are arranged so as to face each other (the directions are opposite) although the collar 26 is interposed between the inner rings. This is because if the two angular ball bearings 21 and 24 are arranged in the same direction, the thrust load in one direction cannot be supported. As a method of arranging two angular ball bearings opposite to each other, as shown in (a) FIG. 1 and FIG. 2 (a), (b), a combination of rear surfaces or a state in which they are arranged in a separated state, or (B) There are two types, that is, the opposite front combination or the arrangement in which they are arranged as they are separated. Either method may be adopted, but the method of all (a) in the above embodiments is that the action line of force (outer ring / ball) applied to each bearing (for example, 21 or 24 in FIG. 2 (b)).・ In the case of (a), the points where the line connecting the contact points of the inner wheels intersects with the axis of the steering shaft 20 (points a and b in Fig. 2 (b)) move away from each other, and the span receiving the moment expands. Therefore, this is more advantageous when a moment load is applied.

The steering device of the present invention is not limited to the front wheels of a motorcycle, but can also be applied to the rear wheels as long as the rear wheels are steered. If a similar steering system is used, automatic 2
The invention is applicable to not only wheeled vehicles but also other vehicles.

[Advantage of the Invention] According to the steering device of the present invention, the bearing has sufficient durability against the load acting on the steering shaft and has a long life, and the structure for mounting the bearing is simple and the number of parts is small. Assembling is easy because there is little and it is not necessary to control the tightening torque of the nut for fixing the bearing. Since the upper bracket is directly contacted with the nut, a thin portion with a step is formed near the upper end of the steering shaft,
It is not necessary to provide any means for stopping the rotation of the nut.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view (side view) of a steering device for a motorcycle according to a first embodiment of the present invention.
(A) and (b) are longitudinal sectional views showing the outline of a steering apparatus as another embodiment. FIG. 3 is a vertical sectional view of a conventional steering device. 1,2a, 2b …… Steering device, 10 …… Head pipe, 2
0 …… Steering shaft, 21,22,23,24 …… Angular ball bearing, 25…
… Deep groove ball bearing, 26 …… Collar, 27 …… Nut, 31 ……
Under bracket, 32 …… Upper bracket.

Claims (1)

[Scope of utility model registration request] 1. An upper bracket and an under bracket in which a steering shaft is rotatably supported by a bearing in a head pipe fixedly mounted on a vehicle body frame, and the upper end and the lower end of the steering shaft are attached respectively. In a steering device of a motorcycle or the like having a structure in which the upper part of the front fork is held by the above, at least two angular ball bearings are arranged to face each other as a part or all of the bearings, and A steering device for a motorcycle or the like, characterized in that only the inner ring is axially tightened by a nut screwed to a steering shaft to be fixed to the steering shaft, and the above-mentioned upper bracket is attached in contact with the nut. .