JPH0514899Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a hub clutch used in four-wheel drive vehicles, and improves response by generating sufficient braking force, especially when transitioning to a lock state. Regarding the hub clutch.

[Conventional technology]

A conventional automatic freewheel hub clutch is disclosed in U.S. Pat. No. 4,327,821. This hub clutch consists of a group of rotating parts that are sequentially assembled on the outer periphery of the driveshaft and fixed parts that are assembled on the spindle. They start working in tandem to connect (lock) the drive shaft and wheel hub. The rotating parts and fixed parts are linked by a fixed brake member and a rotating brake member (brake shoe), and these brake members are connected to the drive shaft and wheel hub during four-wheel drive. Maintain the connection state with. The brake shoe is
It is in sliding contact with the outer circumferential surface of the stationary brake member, and is always pressed against the stationary brake member with a predetermined force by a ring-shaped spring.

[Problem that the invention attempts to solve]

However, in the case of the hub clutch,
There is a problem in that responsiveness decreases or malfunction occurs due to insufficient braking force due to insufficient pressure applied to the sliding part between both brake members by an elastic pressure means such as a spring. There is. Therefore, in order to prevent malfunction, it is necessary to obtain a large braking force, and it is necessary to take measures such as increasing the elastic force of the elastic pressure means and the number of turns. Increasing the power output or the number of windings has been a problem because it causes inconveniences such as premature wear of the brake shoe, resulting in reduced durability, increased cost, and increased axial length.

[Means and actions for solving problems]

The present invention has been devised in view of the above, and eliminates various problems caused by increasing the elastic force of the elastic pressurizing means itself, and by using a fixed brake member in the process of transition to the lock state. The present invention provides a hub clutch that ensures braking of a rotating brake member and improves responsiveness.

〔Example〕

Hereinafter, the hub clutch of the present invention will be explained in detail.

FIGS. 1 to 5 are explanatory diagrams of the configuration of an embodiment of the present invention, in which the hub clutch is fixedly spline-coupled on the outer periphery of the tip end of the axle shaft 1, and has a gear portion 2a for coupling the clutch on the outer periphery. a drive gear 2 having a spline portion 2b; and a cam portion 4a spline-coupled to the spline portion 2b so as to be movable in the axial direction and having a V-shaped protrusion on the inner edge in the axial direction.
A V-groove type in which a cam member 4 having a protruding shape is prevented from rotating by a fixing system (consisting of a spindle 5, a lock nut, etc.) and a thick portion on the outer diameter side of a cam portion 4a of the cam member 4 is fitted into the cam member 4. A brake outer 8 as a fixed brake member having a plurality of cam portions 8a on the outer edge in the axial direction, and a cam portion 4 on the outer edge in the axial direction.
A V-shaped groove-shaped first cam part 9a into which the inner diameter side thick part of a fits, and second cam parts 9 located on both sides of the V-shaped groove-shaped first cam part 9a.
a brake inner 9 as a movable brake member having a protrusion 9f and a brake inner member 9; Projected release plate 11
, a thrust washer 14 disposed via a thrust bearing 13 between the axially inner end of the brake inner 9 and the axially outer surface of the brake outer 8; and the inner peripheral surface of the brake outer 8 and the brake inner 9. A substantially C-shaped wire brake 16 is disposed between the wheels, and a wire brake 16 is fixed to a wheel hub (not shown) with a bolt 20, and has a spline 22 as a gear part on the inner circumferential surface, and an opening 23 at the end surface. A case 24 has a spline 25a on its outer periphery that engages with the spline portion 22 of the case 24 in an axially movable manner, and a gear portion 25b on its inner periphery that engages and disengages the gear portion 2a of the drive gear.
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, a spring holder 32, and a drive gear. 2. A return spring 27 is stretched between the stepped portion 2c on the outer periphery and the spring holder 32, and a return spring 27 is stretched between the bent portion 26b of the retainer and the axially inner wall surface of the slide gear 25, and the return spring 27 is stretched between the bent portion 26b of the retainer and the axially inner wall surface of the slide gear 25 to move the slide gear 25 axially outward. It has a shift spring 28 that biases the shift spring 28 toward the shift spring 28. Cam member 4 and V-groove cam portion 8a of brake outer 8
The V-shaped groove-shaped first cam portion 9a and second cam portion 9b of the brake inner 9 constitute an actuation mechanism that generates a displacement movement. The circlip 12 is fitted onto the outer peripheral surface of the drive gear 2 to prevent the members 4, 11, etc. held on the outer periphery of the drive gear from falling off.

The return spring 27 is configured to have a stronger expansion force than the shift spring 28. A knob 30 is attached to the opening 23 of the case 24 so as to be rotatable manually, and a boss portion 31 is formed protruding from the inner center of the knob 30. The tip of drive gear 2 is axle shaft 1
It protrudes further, and its inner periphery is supported by a tip member 1a fixed to the tip of the axle shaft 1, and this tip member 1a is fixed to the axle shaft 1 with a bolt 1c via a spacer 1b. . A bearing 29 is attached between the outer peripheral surface of the tip member 1a and the inner peripheral surface of the boss portion 31 of the knob. The release plate 11 is disposed to protrude on the outer periphery of the drive gear, and is attached to the arm 11a.
have a positional relationship that allows engagement with the engaged ends 16a, 16b of the wire 16.

The wire brake 16 uses a wire with a round cross section as a first wire brake.
As shown in FIG.
A substantially V-shaped groove 18 is formed in the circumferential direction on the inner circumferential surface of the brake outer 8 with which the brake outer 8 is slidably engaged (FIG. 1c). The bottom of the groove 18 may be flat as shown in the figure, or may be V-shaped and sharp.

As shown in FIG. 1a, the axially outer end of the retainer arm 26a of the retainer 26 is bent radially inward to form a claw portion 26c. A cam surface 31a is formed on the outer peripheral surface of the boss portion 31. This cam surface is a surface that is continuously inclined from the inner side to the outer side in the axial direction, and is configured to be engageable with the claw portion 26c of the retainer 26. The axially inner side of the cam surface is the claw part 2
The opening part 31b is opened so that the entry and exit of the robot 6c is possible.
A recess 31c serving as a lock position is formed on the axially outer side of the cam surface. When the claws 26c of the retainer 26 move axially inward along the cam surface by simultaneous operation of the knob 30 and the claws 26c are disengaged from the cam surface, the automatic state is entered and the claws The portion 26c moves axially outward along the cam surface to the lock position 31.
When it is locked to c, it enters the manual lock state.

In the above configuration, FIG. 1a, FIG. 2a,
During free running (during two-wheel running) in b and c, the driving force is not transmitted to the axle shaft 1, and while the axle shaft 1 does not rotate, each gear portion 2a
and 25b are in the clutch-off (non-meshing) state, so the housing 24, retainer 26, knob 30,
The slide gear 25 and the like rotate. The engagement protrusion 9f of the brake inner 9 is in a non-engaged state with the engaged ends 16a, 16b of the wire brake 16.

Next, the operation for transitioning from the clutch-off state shown in FIG. 1a to the clutch-on state shown in FIGS. 4a and 4b will be described. First, when the driving force from the engine is transmitted to the axle shaft 1, the drive gear 2 and the cam member 4 start rotating together. At this time, the cam portion 4a of the cam member 4 is fitted into the cam groove 8a of the brake outer 8 and the grooved cam portion 9a of the brake inner 9 at the same time, but the grooved cam portion 9a of the brake outer 8 which is a fixed system Due to the thrust force generated at the contact portion with the cam member 4, the cam member 4 attempts to move axially outward while pressing both brakes 8, 9 axially inwardly. The cam portion 4a of the cam member 4 moves axially outward along the grooved cam portion 8a of the brake outer 8, and when it climbs up the groove 8a,
This time it hits the second cam portion 9b of the brake inner 9 (Fig. 3 b, c). At this time, the brake inner 9 has already been rotated by the cam member 4, and the engaging protrusion 9f of the brake inner engages with one engaged end 16b (or 16a) of the wire brake 16 to rotate it. However, since the wire brake 16 is expanded and pressed against the inclined inner wall surface of the groove 18 of the brake outer 8, a large rotational resistance is generated between the two. As a result of the rotation of the wire brake 16 being suppressed, the rotation of the brake inner 9 is also suppressed, and the cam portion 4a is
The cam portion 9b further climbs outward in the axial direction.
When the cam part 4a climbs up the second cam part 9b of the brake inner as shown in FIG. 4, the arm 11a of the release plate 11 engages with the other engaged end 16a of the wire brake 16. In order to rotate the wire brake 16, the wire brake 16 is contracted, and the rotational resistance between the wire brake 16 and the brake outer 8 is significantly reduced. Subsequently, the wire brake 16 is rotated together with the brake inner 9 by the release plate 11. At this time, slide gear 2
5 is displaced axially outward by the elastic force of the shift spring 28, and the gear portion 25b of the slide gear completely meshes with the gear portion 2a of the drive gear to achieve a locked state. When the clutch is fully engaged in this way, the arm 11a of the release plate
engages with the protrusion 9f on the inner periphery of the brake inner 9 via the engaged end 16a of the wire brake, and directly rotates the wire brake 16 while contracting, thereby transmitting rotational torque. Therefore, the braking force using the sliding resistance becomes small, and the resistance based on the relative rotation between the two is sufficiently eliminated, eliminating the possibility of causing problems such as a decrease in durability. The thrust bearing 13 and the thrust washer 14 also contribute to preventing a decrease in durability due to sliding between the brake members 8 and 9.

When changing from a four-wheel drive state to a two-wheel drive state, the transmission of driving force to the axle shaft 1 is cut off, and the vehicle body is slightly moved in the opposite direction to the previous direction of travel. Then, the arm 11a of the release plate 11 separates from the engaged end 16a or 16b of the wire brake, so the wire brake 16 again engages the engagement protrusion 9f of the brake inner.
is pressed in the rotational direction by the brake outer, and is pressed against the inner circumferential surface of the brake outer. The brake inner 9 is connected to the wire brake 16 in the same way as when transitioning from free to lock.
Since the rotation is suppressed by the cam member 4, the cam portion 4a of the cam member 4 moves inward in the axial direction along the second cam portion 9b. Note that at this time, the cam member 4 is pressed inward in the axial direction by the expanding force of the return spring 27, so that the cam portion 4a is pressed against the cam portion 9b.
It becomes easy to displace inward in the axial direction along the axial direction, and finally falls into the cam portion 7a of the brake outer 8 and the cam portion 9a of the brake inner 9. In this way, a clutch-off state is achieved (FIG. 1a, FIGS. 2 a-c). In the process of axially inward displacement of the cam member 4, the gear portion 25b of the slide gear 25 is disengaged from the gear portion 2a by the expanding force of the return spring 27.

Figures 6a and 6b show the state of engagement between the wire brake 16 and the groove 18 of the brake outer according to the present invention, and the state of engagement when there is no groove 18. When there is no groove 18 as shown in FIG. 6b, the contact force (surface pressure) applied to the brake outer surface is P, and the friction coefficient is μ, then the braking force is μP. on the other hand,
When there is a groove 18 as shown in Figure 6a, the surface pressure at the two contact points is P ₁ = P/2cosθ (0<θ<π/
2), the total of each brake force μP ₁ is 2μP ₁ = μP/
becomes cosθ. Since μP/cosθ>μP, therefore, although the braking force at the two contact points increases significantly, the surface pressure does not increase. Therefore,
This has the advantage that while a large braking force can be obtained, the rate of decrease in durability of the sliding portion does not decrease significantly.

Furthermore, the braking force can be significantly increased by simply processing the shape of the groove without making major design changes such as increasing the elastic force of the wire brake or increasing the number of windings. .

Furthermore, since lubricating oil such as grease can be easily held in the gap formed between the bottom surface of the approximately V-shaped groove 18 and the wire brake 16, the durability of the sliding surface within the groove 18 can be improved. I can do it.

Next, by rotating the knob 30, the retainer 2
When the claw portion 26c of No. 6 moves axially inward along the cam surface and the claw portion 26c is out of engagement with the cam surface, the auto state shown in FIGS. 1a to 4a and b is reached. When the claw portion 26c moves axially outward along the cam surface and is locked in the lock position, the manual lock state shown in FIGS. 5a and 5b is achieved.

[Effect of idea]

As described above, according to the hub clutch of the present invention, the rotary brake is braked by the fixed brake member in the process of transitioning to the locked state, without taking complicated measures such as increasing the elastic force of the wire brake itself. By increasing the braking force of the member, response can be improved, and a decrease in durability can be prevented.

[Brief explanation of the drawing]

Figures 1a, b, and c are explanatory diagrams of the entire configuration of an embodiment of the present invention in the free state, a perspective view of the wire brake, and an enlarged view of the engaging portion between the wire brake and the brake outer, and Figure 1d is Exploded diagram of each part,
Figures 2a, b, and c are explanatory diagrams of the engagement states of each cam part, etc. during free operation, and Figures 3a, b, and c are illustrations of the engagement states of each cam part, etc. in the process of transitioning to the auto lock state. An explanatory diagram of the state, Figures 4a and b are explanatory diagrams of the engaged state of each member when the auto is locked, and Figure 5
FIGS. 6A and 6B are explanatory views of the engagement state of each member during manual locking, and FIGS. 6A and 6B are explanatory views showing the relationship between the surface pressure and braking force at the sliding portion of the wire brake and the brake outer. Explanation of symbols, 1...Axle shaft, 2...
Drive gear, 2a, 25b... Gear part, 4...
Cam member, 4a...Cam part, 5a...Spindle, 5b...Lock nut, 8a...Cam part, 8
... Brake outer, 9 ... Brake inner, 9
a, 9b...cam part, 9c...stopper, 10...
...Friction plate, 11...Release plate, 12...
Circlip, 13... Thrust bearing, 1
4... Thrust washer, 16... Wire brake, 18... Groove, 20... Bolt, 22... Spline, 23... Opening, 24... Case, 25
...Slide gear, 2b, 25a... Spline part, 26... Retainer, 26a... Retainer arm, 26b... Bent part, 26c... Claw part, 27...
...Return spring, 28...Shift spring, 29...Bearing, 30...Knob, 31...Boss.

Claims (1)

[Scope of Claim for Utility Model Registration] A case fixed to a wheel hub and having a gear part on the inner periphery; a drive gear fixed to the tip of an axle shaft and having a gear part on the outer periphery; and a case in which the axle shaft is rotated. a brake mechanism that generates a braking force with a fixed system in response to the rotation of the axle shaft; and an actuation mechanism that generates a displacement movement based on the relative rotation generated by the braking force of the brake mechanism when the axle shaft rotates. and a slide gear that connects and disconnects the gear portion of the case and the gear portion of the drive gear by the displacement movement of the actuating mechanism, wherein the brake mechanism is connected to the fixed system. a fixed brake member that is prevented from rotating and has a substantially V-shaped groove in cross section; a movable brake member that is disposed adjacent to the fixed brake member and has a protrusion; and the V-shaped groove of the fixed brake member. 1. A hub clutch comprising: a wire brake which is fitted into the movable brake member, and has an engaged portion having both ends bent in a radial direction to engage with the protrusion of the movable brake member.