JPH0314580Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a hublock that reduces the load on sliding parts during ratcheting.

[Conventional technology]

As a conventional automatic freewheel hub clutch (hereinafter referred to as a hub clutch), U.S. Pat.
There is one disclosed in No. 4327821. This hub clutch has a clutch spline and other splines that are axially movably engaged on the outer periphery of the drive shaft, and an axially slidable spline that is axially slidably engaged with a spline on the inner periphery of the body. a clutch ring having splines that can be coupled; a return spring that is stretched between the clutch cap (lid body) and the clutch ring and biases the clutch ring inward in the axial direction (clutch-off direction); A V-shaped protrusion that is arranged adjacently inward in the axial direction, engages with the other spline on the outer periphery of the drive shaft at the inner periphery so as to be movable in the axial direction, and protrudes inward in the axial direction; A cam follower having protrusions (teeth) projecting in the radial direction, and a V-shaped groove-shaped cam surface on the outer periphery of the axially outer end on which the V-shaped protrusion of the cam follower aligns and seats, and is fixed to a fixing system (lock nut). a movable cam which is coaxially rotatably disposed on the outer diameter side of the cam member and has a substantially V-shaped protruding cam surface axially outward and a cam stop at the tip of the cam surface; It consists of a drag/shut that performs braking between the fixed system and the fixed system. Dratsug・
A thrust washer is disposed at the sliding portion between the axially inner surface of the shoe and the outer surface of the lock nut, and is configured to support the pressing force transmitted from the return spring through the clutch ring, cam follower, movable cam, and drag shoe. has been done. A shift spring is disposed coaxially on the inner diameter side of the return spring, and the shift spring is stretched between a clutch cap and a clutch spline. The clutch ring and the cam follower are in slidable surface contact with each other.

In the above configuration, when the drive shaft starts rotating and torque is transmitted from the other spline to the cam follower, the V-shaped protrusion of the cam follower that has been fitted into the V-shaped grooved cam surface of the cam member is moved into the V-shaped groove. When the cam moves axially outward along the grooved cam surface and crosses the V-shaped groove, the protrusion at the tip engages the V-shaped protrusion of the movable cam (rotation is suppressed by the drag shoe). It engages the cam surface and moves axially outward therealong. When the protrusion passes over the V-shaped groove, the clutch spline on the outer periphery of the drive shaft and the clutch ring have already been engaged, but the protrusion moves axially outward along the protruding cam surface of the movable cam. As the lock deepens, the lock is completed when the cam stop is engaged. This clutch engagement is maintained by the drag shoe braking the movable cam. Further, the clutch spline and other splines are both arranged adjacent to each other on the drive shaft so as to be able to move in the axial direction, but between the clutch spline (located on the outer side in the axial direction) and the clutch cap. A tensioned shift spring elastically suppresses these axially outward displacements.

[Problem that the invention attempts to solve]

However, in the case of the hub clutch, since the axially inner end surface of the clutch ring and the outer end surface of the cam follower are in sliding contact, the clutch spline and the clutch ring engage in latching (end surface The sliding surfaces of the clutch ring and cam follower (which slide based on the relative rotation of the two) wear out due to the loads from the return spring and shift spring. However, durability may be reduced. That is, during ratcheting, the clutch spline is pushed axially outward by the cam follower, so the clutch spline is displaced axially outward and compresses the shift spring. Therefore, in addition to the pressing force from the return spring, a pressing force as a reaction force of the shift spring is applied to the contact surface (sliding surface) between the clutch ring and the cam follower, and the synergistic effect of both pressing forces causes the sliding This accelerates surface wear and significantly reduces durability.

[Means and actions for solving problems]

The present invention was developed in view of the above, and in order to reduce the wear of the sliding parts between the housing side member and the drive shaft side member during ratcheting and improve durability, the pressing force of the return spring is reduced. To provide a hub lock that does not touch the sliding part at all.

〔Example〕

Hereinafter, the hub clutch (hereinafter referred to as hub lock) of the present invention will be explained.

Figures 1 to 4 A and B show the first embodiment of the present invention, and this hub lock is attached to the axle shaft 1.
A drive gear 2 having a first spline 3a and a second spline portion 3b for clutch connection on the outer periphery, which are fixedly spline-coupled on the outer periphery of the tip end of the drive gear 2.
is spline-engaged with the second spline portion 3b so as to be movable in the axial direction, and a V is formed on the axially inner edge.
A first cam 4 in which a projecting cam portion 4a is formed in a protruding manner.
and a V whose rotation is suppressed by a fixing system (consisting of a spindle 5 and a lock nut (not shown), etc.) and into which the thick portion on the outer diameter side of the cam portion 4a of the first cam fits.
A second groove-shaped cam portion 7a having a plurality of groove-shaped cam portions 7a on the outer edge in the axial direction and a conical friction surface 7b on the inner periphery.
cam 8 , and a first cam portion 9 in the form of a V-shaped groove in which the thick inner diameter portion of the cam portion 4a fits into the axially outer edge thereof.
a, a second cam part 9b and a stopper 9c located on both sides of the first cam part 9a, and the axially inner outer circumferential surface is the friction surface 7b of the inner circumference of the second cam 8.
A cam ring 9 serves as a braking surface that slides with the cam ring to generate the required braking force, and a cam ring 9 is fixed to a wheel hub (not shown) with bolts and has a spline 22 on its inner peripheral surface and a protrusion 23 at the center of the inner side of the end surface.
a ring clutch 25 having a spline 25a on the outer periphery that engages with the spline 22 of the case 24 in an axially movable manner, and a spline 25b on the inner periphery that engages and disengages the first spline 3a of the drive gear. and,
A retainer arm 26a whose rotation is suppressed by a spline 22, a retainer 26 having a bent portion 26b radially inward on the axially inner side of the retainer arm 26a, and a retainer 26 that extends axially outward from the inner diameter portion of the first cam 4. The bent part 2 of the retainer integrally protrudes on the outer peripheral surface.
The overhanging portion 4b that supports the inner peripheral surface of the 6b (the overhanging portion 4b is
The dimensions are set so as to protrude further in the axial direction than the axial side surface of the bent portion 26b. ), a washer 40 that comes into contact with the axially outer end surface of the overhang portion 4b so as to be able to move freely in the axial direction, and a stepped portion 3 on the outer periphery of the drive gear 2.
The first cam 4 is stretched between the washer 40 and the washer 40.
and a return spring 27 that urges axially inward.
and a shift spring 28 which is stretched between the bent portion 26b of the retainer 26 and the inner wall surface of the ring clutch 25 in the axial direction and urges the ring clutch 25 outward in the axial direction. Overhanging portion 4b and washers 40
A return spring support is constructed from the above. In other words, the return spring support part is the first
It is located between the axially outer part of the cam 4 and the return spring 27, and is movable in the axial direction.
It has a larger axial length. Second
The conical friction surface 7b on the inner circumference of the cam 8 and the friction surface formed on the inner outer circumference of the cam ring 9 constitute a brake mechanism. Return spring 27
has a stronger expanding force than the shift spring 28. The tip of the drive gear 2 protrudes from the tip of the axle shaft 1, and a bearing 29 is installed between the inner periphery of the tip of the axle shaft 1 and the protrusion 23 of the case. The bearing 29 is prevented from falling off in the axial direction by having its inner diameter portion locked by the stepped portion 23a of the protruding portion 23 and its outer diameter portion locked by the inner stepped portion of the drive gear 2. There is. Symbol 2a is a protrusion on the outer periphery of the drive gear,
It has a positional relationship that allows it to engage with the protrusion 9d inside the cam ring. The protrusion 2a may be made separate from the drive gear 2 by spline engagement as shown in Fig. 1 and fixed with a circlip, or it may be integrated as shown in Figs. It may be made into

FIGS. 5A, 5B, and 5C show a second embodiment of the present invention, in which the braking between the second cam 8 and the cam ring 9 is achieved by using a clutch plate 5 instead of using a conical friction surface.
This is done by 0.51. The second cam 8 is similar to the one shown in FIG. 1 in that it has a grooved cam portion 7a, but instead of the friction surface 7b, it has a notch for fitting the lug portion 51a on the outer periphery of the clutch plate 51. The difference is that 8a is formed. The cam ring 9 has a first cam portion 9a and a second cam portion 9b.
and the first in that it has a stopper 9c.
Although it is the same as that shown in the figure, the difference is that a notch 9f for fitting the inner diameter side lug portion 50a of the clutch plate 50 is formed in the cylindrical protrusion 9e.
The protrusion 9e is fitted into the central hole of each clutch plate. Each clutch plate 51 is prohibited from rotating by the first cam portion 9a, and is allowed to move in the axial direction within a predetermined range. A clutch plate 50 is disposed between each clutch plate 51, and its lug portion 50
Since the clutch plate 50 is locked by the notch 9f of the cam ring so as to be movable in the axial direction, the clutch plate 50 rotates integrally with the movement of the cam ring 9 in the rotational direction.

In the above configuration, the operation for transitioning from the clutch-off state shown in FIGS. 2A and 5A to the clutch-on state shown in FIGS. 2B and 5C will be described. First, when the driving force from the engine is transmitted to axle shaft 1, drive gear 2
Then, the first cam 4 starts rotating integrally. In the clutch-off state, the cam portion 4a of the first cam 4 is fitted into and engaged with the groove-shaped cam portion 7a of the second cam 8 and the first cam portion 9a of the cam ring 9 at the same time, but the rotation of the axle shaft 1 When the first cam 4 starts rotating, the cam portion 4a is moved axially outward along each cam surface of each cam portion 7a and 9a due to the axially outward thrust force generated on each cam surface. Displace. After the cam portion 4a passes over the grooved cam portions 7a and 9a, the cam portion 4a then moves to the second cam portion 9 of the cam ring.
b and is displaced axially outward along this, and hits the stopper 9c to stop the axial displacement. When the return spring 27 is deflected by the axial movement of the first cam 4, the ring clutch 25 is displaced axially outward by the shift spring 28, and the spline 25b and the spline 3a
and completely mesh (Figure 2B, Figure 5C). When the clutch is fully engaged, the protrusion 2a on the outer circumference of the drive gear engages with the protrusion 9d on the inner circumference of the cam ring 9, directly rotating the cam ring 9 and transmitting rotational torque.

Next, when changing from four-wheel drive to two-wheel drive, cut off the transmission of driving force to axle shaft 1, and then move the vehicle slightly in the opposite direction to the previous direction of travel. The cam portion 4a of the first cam 4 is
is separated from the stopper 9c, displaced axially inward along the cam portion 9b, and finally falls into the cam portion 7a of the second cam 8 and the cam portion 9a of the cam ring 9. In this way, a clutch-off condition is achieved. In the process of axially inward displacement of the first cam 4, the spline 25b of the clutch ring 25 changes to the spline 3.
The mesh with a is released. Since the spline 22 of the case only supports the clutch ring 25 in a slidable manner, there is no need to construct it from a material with high strength and weight such as steel. Therefore, the weight can be reduced by using aluminum alloy or the like.

Next, in the process of transitioning from the clutch-off state in Figure 5A to the clutch-on state in Figure 5C,
When the ratcheting state shown in FIG. 4 and the inner surface of the bent portion 26b of the retainer 2.
Only the reaction force of the shift spring 28 is applied via the shift spring 6. For this reason, when ratcheting,
Even if the retainer 26 and the first cam 4 undergo relative rotation and their contact surfaces slide, there is no risk of significant wear occurring. Therefore, there is no fear that the durability of the sliding portion will deteriorate rapidly.

In the braking section having the configuration shown in FIGS. 5A to 6C and FIG. 6, when the drive shaft starts rotating and the first cam 4 presses the cam ring 9 inward in the axial direction, the cam ring 9 The cam ring 9 is braked by pressing each clutch plate 50, 51 between the second cam 8 and the second cam 8.

In addition, in the above embodiment, the fitting relationship between the protruding cam portion and the grooved cam portion is shown, but by replacing the protruding cam portion and the grooved cam portion with each other, it is possible to If similar effects can be achieved, such a fitting relationship also falls within the scope of the present invention.

[Effect of idea]

As described above, according to the hub lock of the present invention, since the pressing force of the return spring is not applied to the sliding part at all, the sliding part between the housing side member and the drive shaft side member is worn out during ratcheting. can be reduced to improve durability.

[Brief explanation of the drawing]

1 to 4 A and B show a first embodiment of the present invention, FIG. 1 is an explanatory diagram of the overall configuration, and FIGS. 2 A and B are explanatory diagrams of the engaged state of each cam part, FIGS. 3A and 3B and FIGS. 4A and 4B are explanatory diagrams of the state of engagement between the protrusion of the drive gear and the protrusion of the cam ring when the clutch is off and on. Figure 5 A,
Figures B, C to 6 show a second embodiment of the present invention, where Figure 5A is an explanatory diagram at the time of clutch off, Figure 5B is an explanatory diagram at the time of ratcheting, and Figure 5C is an explanation at clutch on. FIG. 6 is an explanatory diagram of the structure of the braking section shown in FIG. 5. Explanation of symbols, 1...Axle shaft, 2...
Drive gear, 2a... protrusion, 3a, 3b... spline, 4... first cam, 4a... cam part,
5... Spindle, 7a... Cam portion, 7b... Friction surface, 8... Second cam, 9... Cam ring, 9
a...first cam part, 9b...second cam part, 9
c...Stopper, 9d...Protrusion, 22...Spline, 23...Protrusion, 24...Case, 25...
... Ring clutch, 25a, 25b ... Spline, 26 ... Retainer, 26a ... Retainer arm, 26b ... Bent part, 27 ... Return spring, 28 ... Shift spring, 29 ... Bearing, 40 ... Washer, 50, 51...Clutch plate.

Claims (1)

[Scope of Claim for Utility Model Registration] A cylindrical case fixed to a wheel hub and having a spline on the inner periphery; a drive gear fixed to the outer periphery of the tip of an axle shaft and having a spline on the outer periphery; and the drive gear A first cam having a cam portion that is spline-engaged to the outer periphery so as to be movable in the axial direction, and a cam portion that is prevented from rotating by a fixing system and that engages with the cam portion of the first cam. a second cam; a cam ring having a first cam part that engages with the cam part of the first cam; and a second cam part connected to the first cam part; a brake mechanism that is provided between the cam portion of the cam and the cam ring and generates a braking force; and a brake mechanism that is axially movably supported by the splines on the inner periphery of the case and that, when displaced in the axial direction, engages the splines on the outer periphery of the drive gear. a ring clutch that engages the clutch; a retainer that slides into contact with an axially outer surface of the first cam, engages the ring clutch, and rotates integrally with the case; and a retainer that rotates integrally with the case; a return spring support disposed so as to be movable in the axial direction on the outside; and the first cam, which is stretched between the return spring support and a stepped portion on the outer periphery of the drive gear, axially inward. A hub lock comprising: a pressing return spring; and a shift spring stretched between the first retainer and the ring clutch.