JPH031301Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention is provided between the axle shaft and its wheel hub, which is rotatably driven only during four-wheel drive of a four-wheel drive vehicle, and is used for four-wheel drive operation. Therefore, the present invention relates to an auto-locking hub that automatically connects (locks) the axle shaft and the wheel hub so that power can be transmitted.

(Prior Art) As this type of auto-locking hub, the one shown in, for example, Japanese Unexamined Utility Model Publication No. 59-49532 is already known, and the present applicant has also reported, for example, We already provide the configuration shown in . Therefore, to summarize the structure and functions of this, an inner cam is attached to the outer periphery of an inner hub that is fixed to an axle shaft that is rotatably driven only during four-wheel drive, and that the inner cam is relatively rotatable. When a predetermined braking torque is applied to the inner cam at the initial stage of driving, the clutch for locking or releasing the lock between the axle shaft side and the wheel hub side becomes capable of transmitting power between the axle shaft side and the wheel hub side. It is operated to the locked position. The torque for the inner cam at this time can be obtained as follows. That is, a brake spring placed inside the brake shoe fixed to the inside of the brake drum is expanded by the action of the inner cam at the initial stage of driving the axle shaft, and as a result, the brake spring and brake are expanded. This generates a frictional force between the inner cam and the shoe, which applies braking torque to the inner cam.

In this way, in order to lock the axle shaft side and the wheel hub side so that power can be transmitted, it is extremely important to appropriately apply a predetermined braking torque to the inner cam.

(Problem to be Solved by the Invention) In the auto-locking hub having the above configuration, there is a function inside the brake shoe that provides the above-mentioned expansion action to the brake spring incorporated therein, and A portion of the inner cam or outer cam is inserted to provide the contraction effect as described above. For this reason, both sides of the brake shoe are open.
When the vehicle is running at high speeds, the brake grease in the brake shoe may scatter toward other parts, or at the same time, it may leak from other parts (wheel bearings, constant velocity joints, auto-locking hub bodies, differential mechanisms, etc.) There is a risk of stains if foreign grease or lubricating oil gets into the brake shoe. As a result, the friction coefficient between the brake shoe and the brake spring changes, and the braking torque to the inner cam becomes unstable.
There may be cases where the axle shaft side and the wheel hub side described above are not locked or unlocked smoothly. In addition, the fact that the grease inside the brake shoe is scattered to other parts causes an increase in the amount of wear on the brake shoe, and at the same time, the wear particles can enter other parts (such as wheel bearings, etc.). Problems that are said to have negative effects also arise.

(Means for Solving the Problems) In order to solve the above problems, the present invention proposes that the brake shoes 6 have respective opposing portions to the outer periphery of the inner hub 8 and the outer periphery of the outer cam 11, as shown in FIGS. 1 and 2. Seal bodies 20 and 21 are fixed to the outer peripheral surfaces of the inner hub 8 and the outer cam 11 so as to continuously contact them in the circumferential direction.

(Function) According to the above configuration, even if the inner hub 8 or the outer cam 11 rotates at high speed when the vehicle is running at high speed, the brake grease in the brake shoe 6 is prevented from scattering to other parts. A predetermined amount of grease is always kept inside the brake shoe 6. Furthermore, since the inside of the brake shoe 6 is isolated from other parts by the seal bodies 20 and 21, foreign grease and lubricating oil can leak into the brake shoe 6 from other parts.
The inconvenience caused by intrusion into the inside of the computer is also avoided.
As a result, the friction between the brake shoe 6 and the brake spring can always be maintained in a stable state, and the braking torque applied to the inner cam can always be maintained at an appropriate level.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

First, in FIG. 1 showing the internal structure of an auto-locking hub, a wheel hub 3 is rotatably assembled on the outer periphery of an axle housing 1 by a wheel bearing 2 using a tapered roller bearing. . A body 4 is fixed to the end of the wheel hub 3 by bolts 16, and a brake drum 5 is fixed to the end of the axle housing 1 inside the body 4 and the wheel hub 3.

Further, an axle shaft 7 is inserted into the inside of the axle housing 1, and an inner hub 8 is fixed to the outer periphery of the end of the axle shaft 7 so as to be able to rotate together with the axle shaft 7. A clutch 9 is attached to the outer periphery of the inner hub 8 by spline fitting so that it can rotate together with the inner hub 8 and slide along the outer periphery of the inner hub 8. In addition,
External teeth 9a are formed on the outer periphery of this clutch 9 and mesh with internal teeth 4a formed on the inner periphery of the body 4.

An annular shape is formed on the outer periphery of the inner hub 8,
An inner cam 10 having a cam surface 10a on its right end surface is rotatable relative to the inner hub 8, and is assembled in a positioned position in the axial direction. Further, an annular outer cam 11 is attached to the outer periphery of the inner cam 10 so as to be rotatable relative to the inner hub 8 and the inner cam 10, respectively. A cam follower 12 formed in an annular shape is attached to the inner periphery of the inner cam 10 by spline fitting so that it cannot rotate relative to the inner hub 8 but is slidable in the axial direction.

Between the cam follower 12 and the clutch 9, there is a return spring 15 that acts to push the cam follower 12 back to the state shown in the upper side of FIG. Joint 13 and preset spring 1 as a connecting means for transmitting
4 are interposed respectively.

On the other hand, a brake shoe 6 is fixed to the inner periphery of the brake drum 5 fixed to the end of the axle housing 1, and a coiled brake spring 17 is arranged inside the brake shoe. ing. Each of the brake springs 17 includes a pair of claws 17a bent toward the center of the coil. Between these claws 17a, a projection 10b is located which projects from the inner cam 10 to the left in FIG. A pair of protrusions (not shown) are positioned to protrude in the direction.

As is clear from FIG. 2, which is a partially enlarged view of the brake shoe 6, the left and right side walls 6a, 6b of the brake shoe 6 are formed on the outer peripheral surface of the inner hub 8 and the outer cam 11. They are facing each other. Ring-shaped seal bodies 20 and 21 that continuously contact the outer peripheries of the inner hub 8 and the outer hub 10 in the circumferential direction are fixed to these opposing parts, respectively. These seal bodies 20 and 21 are made of a material such as rubber that can maintain oil tightness between the side walls 6a and 6b of the brake shoe 6, the inner hub 8, and the outer cam 11.

In the auto-locking hub configured as described above, when the rotational drive of the axle shaft 7 is started by switching from two-wheel drive to four-wheel drive, the inner hub 8 that rotates together with the axle shaft 7 is rotated. The cam follower 12 also rotates. As a result, the cam follower 12 hits the cam surface 10a of the inner cam 10, causing the inner cam 10 to rotate. Due to this rotation of the inner cam 10, the protrusion 10b is attached to one of the pawls 17 of the brake spring 17.
When engaged with a, this brake spring 17 receives a force in the expansion direction. As a result, the brake spring 17 expands to generate a frictional force between its outer periphery and the brake shoe 6 on the inner periphery of the brake drum 5, and based on this, a braking torque is applied to the inner cam 10.

By applying braking torque to the inner cam 10, relative rotation occurs between the inner cam 10 and the cam follower 12, and the cam follower 12 resists the elasticity of the return spring 15 due to the action of the cam surface 10a of the inner cam 10. While doing so, it slides to the right from the return position shown on the upper side of FIG. 1 to reach the position shown on the lower side of FIG. 1 as well. The sliding motion of the cam follower 12 is transmitted to the clutch 9 through the joint 13 and preset spring 14, and the clutch 9 has its external teeth 9a connected to the internal teeth 4 of the body 4.
A is slid to the lock position where it engages with the lock (see the state shown at the bottom of FIG. 1). As a result, the body 4 and the inner hub 8 are connected (locked) so that rotation can be transmitted through the clutch 9.
The axle shaft 7 and the link hub 3 are then in a locked state and rotate integrally.

Note that after the axle shaft 7 and wheel hub 3 are completely locked, the cam follower 12 hits the protrusion 11a extending to the right of the outer cam 11,
This outer cam 11 starts rotating together with the cam follower 12. As a result, a leftward extending protrusion (not shown) of the outer cam 11 engages with one of the pawls 17a of the brake spring 17, applying force in a direction that causes the brake spring 20 to contract. As a result, the frictional force between the brake shoe 6 and the outer periphery of the brake spring 17 is reduced, and the braking torque applied to the inner cam 10 is also reduced.

As already mentioned, brake grease is sealed inside the brake shoe 6.
As a result, an appropriate frictional force is always obtained as required between the inner peripheral surface of the brake shoe 6 and the outer peripheral surface of the brake spring 17, and at the same time, wear of the brake shoe 6 is also prevented. As described above, seal bodies 20 and 21 are provided between the side walls 6a and 6b of this brake shoe 6 and the respective outer peripheral surfaces of the inner hub 8 and outer cam 11, so that when the vehicle is running at high speed, Even if the inner hub 8 or the outer cam 11 rotates at high speed, the brake grease sealed inside the brake shoe 6 can be prevented from scattering to other parts, and the inside of the brake shoe 6 can be prevented from scattering to other parts. A predetermined amount of grease is always available.

Also, the fact that the inside of the brake shoe 6 is isolated from other parts by the seal bodies 20 and 21 in this way means that, for example, the inside of the brake shoe 6 is isolated from other parts by the arrows in FIG. Grease and lubricating oil flowing in the direction A are also prevented from entering the inside of the brake shoe 6, and foreign grease and lubricating oil mixed into the inside of the brake shoe 6 cause the brake shoe 6 to
Inconveniences caused by changes in the coefficient of friction between the brake spring 17 and the brake spring 17 are avoided. Note that the grease and lubricating oil flowing toward the brake shoe 6 not only flow in the direction of arrow A from the constant velocity joint and differential mechanism described above, but also flow in the direction of arrow B in FIG. 2 from the wheel bearing 2. Examples include grease, lubricating oil, and oil flowing in the direction of arrow C in Figure 2 within the autolocking hub, but these greases and oils are also prevented from entering the brake shoe 6 in the same way as above. Ru.

Next, in order to release the lock between the axle shaft 7 and the wheel hub 3, the axle shaft 7 is not actively rotated, that is, the vehicle is switched to a two-wheel drive state, and the vehicle is moved slightly backward, for example. The rotation of the wheel hub 3 at this time is transmitted to the inner hub 8 via the clutch 9. As a result, the cam follower 12 is connected to the inner cam 10.
The protrusion 10 of the inner cam 10 rotates with
b engages with the pawl 17a of the brake spring 17 to apply braking torque to the inner cam 10. As a result, the clutch 9 and the cam follower 12 rotate together relative to the inner cam 10, and the cam follower 12, being acted on by the return spring 15, changes from the state shown in the lower part of FIG. It is pushed back to the state shown in the upper part of FIG. As a result, the clutch 9, which is connected through the joint 13 and the preset spring 14, also returns to the unlocked position shown in the upper part of FIG. 1, and the lock between the axle shaft 7 and the wheel hub 3 is released. be.

(Effects of the invention) As described above, the present invention provides a seal that continuously contacts the outer peripheral surfaces of the inner hub and the outer cam in the circumferential direction at the opposing portions of the inner hub outer periphery and the outer cam outer periphery of the brake shoe. By fixing the body, it is possible to prevent the brake grease inside the brake shoe from scattering to other parts when the vehicle is running at high speed. In addition, it is possible to prevent a situation where foreign grease or lubricating oil gets mixed in from other parts. As a result, the friction between the brake shoe and the brake spring can always be maintained in a stable state, and the braking torque to the inner cam can always be maintained at an appropriate level. It is possible to properly lock and release the lock with the other party. Moreover, being able to always maintain a predetermined amount of grease in the brake shoe prevents abnormal wear of the brake shoe and improves its durability, and also allows the wear particles of the brake shoe to enter other parts. It is also possible to prevent situations that could have negative effects.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is a sectional view showing the internal structure of the auto-locking hub, and Fig. 2 shows a part of the brake shoe corresponding to the part in Fig. 1. It is an enlarged sectional view. 1...Axle housing, 3...Wheel hub,
5... Brake drum, 6... Brake shoe,
7...Axle shaft, 8...Inner hub, 9
...Clutch, 10...Inner cam, 11...Outer cam, 17...Brake spring, 20,
21... Seal body.

Claims (1)

[Scope of utility model registration request] A wheel hub is rotatably assembled on the outer periphery of the axle housing into which the axle shaft, which is rotationally driven only during four-wheel drive, is inserted. Outer cams located on the outer periphery of the outer cams are assembled to be rotatable relative to each other, while a brake shoe is fixed to the inside of the brake drum fixed to the axle housing, and the brake shoe is arranged inside the brake shoe. At the initial stage of driving the axle shaft, the inner cam expands the brake spring, and the resulting frictional force between the brake spring and the brake shoe applies braking torque to the inner cam. The autorot is configured to lock the axle shaft and the wheel hub by clutch control based on the braking torque, and then contract the brake spring by the action of the outer cam, thereby reducing the braking torque. It is a king hub, and a seal body that continuously contacts the outer circumferential surfaces of the inner hub and the outer cam in the circumferential direction is fixed to each opposing portion of the inner hub outer periphery and the outer cam outer periphery of the brake shoe. An autorotsking hub featuring: