JPH0224686B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to freewheel hub devices.

[Technical Background and Problems] Generally, in a vehicle that can be switched between two-wheel drive and four-wheel drive, when the driver selects two-wheel drive, the vehicle is driven only by the rear wheels. As the vehicle moves, the front wheels receive driving force from the road surface and rotate, which causes the axle shaft, differential device, drive shaft, etc. connected to the front wheels to rotate, which reduces fuel consumption and noise. be at a disadvantage.

In view of this point, there is a conventional freewheel hub device as shown in FIG.

That is, a spindle 3 is housed within the hub 1, and an axle shaft 5 is disposed through the spindle 3. A drive gear is spline-fitted to the tip of the axle shaft 5.

On the other hand, the hub 1 has a cover case 9, which is fastened and fixed with bolts 11, and a knob 13 is rotatably fitted into the cover case 9. A cam wall 15 is formed on the inner surface of the knob 13 to protrude inward, and the outer periphery of the cam wall 15 is formed into a cam surface 15a. A clutch ring 17 is provided on this cam surface 15a.
are cam-connected, and the clutch ring 17 moves forward and backward as the knob 13 rotates forward and backward. The outer surface of the clutch ring 17 has a spline 9 provided on the inner surface of the cover case 9.
An outer spline 17a that meshes with the drive gear 7 is formed on the inner surface, and an inner spline 17b that meshes with the drive gear 7 is formed on the inner surface. Cam surface 1 provided on this clutch ring 17 and the knob 13
5a and cover case 9 and drive gear 7.
A clutch mechanism is configured to connect or disconnect the two.

A bush 19 is fitted into the inner peripheral surface of the hub 1 so as to be slidable relative to the inner peripheral surface. A centering reference surface 19a is formed on the inner surface of this bush 19.
is a ring 2 fixed to the outer periphery of the drive gear 7.
The first reference receiving surface 21a is fitted so as to be in sliding contact.

In the above configuration, when the knob 13 is rotated in a desired direction, the clutch ring 17 is advanced by the cam action, and the internal spline 17b is engaged with the drive gear 7. As a result, the hub 1 and the axle shaft 5 are connected to each other. is achieved, and the vehicle becomes capable of running in four-wheel drive. On the other hand, when the knob 13 is turned back in the opposite direction from this state where four-wheel drive driving is possible, the clutch ring 17 is moved backward by the cam action, and the engagement between the inner spline 17b and the drive gear 7 is changed. It comes off. This results in
The connection between the hub 1 and the axle shaft 5 is severed,
For example, it is possible to idle the front wheels when driving in two-wheel drive.

However, with this type of conventional device,
This is done by fitting the bush 19 on the centering 1 side of the axle shaft 5 and drive gear 7 with the ring 21 on the drive gear 7 side.
There was a problem that the following disadvantages occurred. That is, when driving a vehicle, it is generally the case that two-wheel drive vehicles are used much more frequently than four-wheel drive vehicles. However, in this two-wheel drive, as mentioned above, since the hub 1 and the drive gear 7 are disconnected, relative rotation between the bush 19 and the ring 21 occurs frequently, and as a result, the centering reference plane There was a fear that seizure between the reference receiving surface 21a and the reference receiving surface 21a would easily occur. Furthermore, even if seizure does not occur, the drive gear 7 rattles due to wear and the boss portion 7a of the drive gear 7 rotates in contact with the inner surface of the cam wall 15 of the knob 13, and as a result, the knob 13 rotates. Therefore, there was a risk that the clutch ring 17 would move forward and interfere with the drive gear 7.

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a freewheel hub device that can reduce seizure and wear of the centering portion.

[Structure of the Invention] In order to achieve the above object, the present invention includes a centering reference surface formed on the circumferential surface of the tip end of the spindle, and a reference receiving surface formed on the drive gear side.
The centering reference surface and the reference receiving surface are fitted into each other.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. In addition, in this description, the same reference numerals are given to the same members as those of the conventional device, and the description thereof will be omitted.

FIG. 2 shows an embodiment of the device according to the invention. The difference in FIG. 2 from FIG. 1, which shows the conventional device, lies in the fitting structure between the spindle 3 and the drive gear 7.

That is, a centering reference surface 23 is formed around the tip of the spindle 3. On the other hand, a reference receiving surface 25 is formed on the drive gear 7 at a position facing the spindle 3, and the reference receiving surface 25 is fitted to the centering reference surface 23 in an appropriate fitted state without any play. ing.

One embodiment of the present invention has the above configuration, and its operation will be explained below.

In the frequently used two-wheel drive state, as shown in FIG. 2, the clutch ring 17 is in the backward position, so the cover case 9 and drive gear 7 are disconnected, and the hub 1 and axle shaft are disconnected. The connection with 5 is broken and the wheels spin. At this time,
Since there is no relative rotation between the spindle 3 and the drive gear 7, and both 3 and 7 remain stationary,
Sliding wear and seizure between the centering reference surface 23 and the reference receiving surface 25 will not occur. Therefore, by fitting these two parts 23 and 25 together, the drive shaft 5 is correctly maintained at the rotational center position, and there is no problem caused by misalignment of the rotational center position as seen in conventional devices.

On the other hand, when the vehicle is running in four-wheel drive, the clutch ring 17 moves forward and engages with the drive gear 7 to connect the drive gear 7 and the cover case 9. As a result, the centering reference plane 23 However, as mentioned above, not only does the frequency of four-wheel drive driving of the vehicle become very low, but also because the centering diameter can be made smaller compared to the conventional device, the sliding occurs. Since the circumferential speed of the moving surface is reduced, wear and seizure of both surfaces 23 and 25 of the fitting portion is extremely reduced as the rotational center position of the drive shaft 5 is shifted due to the sliding movement.

[Effects of the Invention] As is clear from the above description, in the present invention, the frequency of relative rotation of the centering portion is reduced and the circumferential speed can be reduced, so that seizure and wear can be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a conventional freewheel hub device, and FIG. 2 is a sectional view of a main part of a freewheel hub device showing an embodiment of the present invention. 1...Hub, 3...Spindle, 5...Axle shaft, 7...Drive gear, 9...Cover case, 1
3... Knob, 17... Clutch ring, 23... Centering reference surface, 25... Reference receiving surface.

Claims (1)

[Claims] 1. A spindle supported on the vehicle body side, a drive gear fixed to an axle shaft passing through the spindle, a hub having a spline on its inner surface, and a clutch mechanism for connecting and disconnecting the drive gear and the spline. In the freewheel hub device, a centering reference surface is formed on the peripheral surface of the tip of the spindle, and a reference receiving surface is formed on the drive gear side, and the reference receiving surface is fitted to the centering reference surface. Features a freewheel hub device.