JPH03255232A - Automatic clutch - Google Patents

Abstract

PURPOSE:To separate an outer cam smoothly by forming an outer cam tooth and an inner cam tooth into an angle for rotation of the inner cam within a prescribed rotating area. CONSTITUTION:When rotational force is transmitted to a driving shaft 1 by turning on a clutch, the cam tooth 43 of a fixed side inner cam 40 and the cam tooth 33 of a driving side outer cam 25 generates wedge force between both teeth 33, 43 through its angle to separate the outer cam 25. Since the wedge force gives force to a hole-out ring 35 in a thrust direction, an out-ring 35 rotates in the same direction as the outer cam 25, however, rotation is inhibited by a drop part 59 between the protruding part 37 of the outer ring 35 and the end of a knuckle spindle 2. The outer tooth 29b of a drive clutch 23 and the inner tooth 29a of a driven clutch 7 work at a stretch through a spring 24 for smooth engagement. When the top faces of the cam teeth 33, 43 butts each other at the time of separation, the inner cam 40 rotates by a prescribed number for smooth engagement.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic clutch that is adopted in vehicles and the like to connect and connect a driven member and a driving member, and in particular, to smoothly perform the operation when connecting and connecting the clutch. This invention relates to an automatic clutch that has improved durability and reliability.

[Prior Art] When a vehicle is running, when the road surface becomes frozen or snowy, it becomes difficult for the driving force to be transmitted from the tires to the road surface, making the running unstable. A four-wheel drive system is adopted. However, when a vehicle that uses this four-wheel drive system is driven on roads with good surface conditions, unnecessary drive systems are operated.
output.

It becomes uneconomical in terms of fuel consumption. Therefore, automatic clutches have been developed that can cut off the driving force to the wheels when unnecessary, allowing the wheels to rotate freely.

As a prior example of an automatic clutch, a proposal by the present applicant (Japanese Patent Application Laid-Open No. 56-31530) shown in FIGS. 11 and 12 is known. In this proposal, as shown in FIG. 11, a drive clutch b is provided on a drive shaft a so as to be movable in the axial direction and to prevent relative rotation with respect to the drive shaft. An outer cam C is slidably provided on the outer peripheral surface of the drive clutch b. On the other hand, an inner cam e, with which the outer cam C is removably engaged, is fixed to a knuckle d for rotationally supporting the drive shaft a. A plurality of stopper pieces f are formed at intervals on the outer circumferential surface of the inner cam e and protrude outward in the radial direction, and a holdout ring g is provided on the outer circumferential surface of the outer cam C so as to be rotatable in the circumferential direction. They are fitted and provided. As shown in FIG. 12, this holdout ring g is provided with a ring for abutting against the circumferential end surface of the stopper piece f of the inner cam e to prevent rotation when the outer cam C is in the disengaged position, and a stopper piece f for stopping the inner cam e from rotating. Projections are formed at intervals to abut against the axial end face of the cam and to keep the outer cam C and the inner cam e from separating from each other. In addition, in this proposal, a lock spring i is interposed between the drive clutch b and the inner cam e, and a retainer j fitted to the tip of the drive shaft a and the drive clutch b
A return spring k is interposed between them. Further, when the outer cam C is disengaged, the drive clutch b and the driven clutch n of the wheel hub m are engaged with each other via the thrust bin j, and the rotation of the drive shaft a is transmitted to the wheel hub m.

Briefly explain the operation and operation when detaching.

The first operation is to turn off the front wheel drive of the transfer and to turn off the power transmission to the drive shaft (not shown).
Make it F. Second, the direction of travel of the vehicle is reversed to the direction of travel before this operation, and the vehicle is made to travel slowly.

As a result, the protrusion of the holdout ring is disengaged from the stopper piece of the inner cam, and the holdout ring and outer cam are rotated in the rotational direction of the drive shaft. At the same time, the regulation of the elastic force of the return spring is lost, so when the inner cam and the outer cam are in phase, they engage and the drive clutch is disengaged from the driven clutch. As a result, the wheel hub can rotate freely.

[Problem to be Solved by the Invention] However, since the above-mentioned automatic clutch is provided separately for each of the two front wheels, there is actually a difference between the rotation angle of one wheel hub and the rotation angle of the other wheel hub. If a phase difference occurs between the two clutches, there is a problem that even though one clutch is switched to a free state (outer cam and inner cam are engaged), the other clutch may be in a locked state (outer cam and inner cam are disengaged). there were. This is generally called one-sidedness. In other words, the differential function of the differential tries to turn the side with a smaller load faster, so
Although the outer cam attempts to engage with the inner cam of the automatic clutch on the lock side, the top surfaces of the cam teeth slide against each other, causing abnormal noise and abnormal wear. are doing. For this reason, in the past, the two automatic clutches on the front wheels were monitored to ensure that one side did not disengage, and the vehicle was moved slowly to perform switching, but this was not a desirable switching operation and the solution was to solve this problem. was being asked for.

[Means for Solving the Problems] The present invention aims to solve the above problems,
The present invention provides a drive clutch that is rotated integrally with respect to a drive shaft, is movable along the axial direction, and is biased with an elastic force in a disengagement direction with respect to a driven clutch of a driven member. is located on the fixed system side that rotatably supports the drive shaft, rotates integrally with the drive shaft, and is movable along the axial direction, and connects the driven clutch via the drive clutch. The outer cam is biased in the detachment direction, has a predetermined rotation range with respect to the fixed system, is biased in the opposite direction of rotation, and is movable in the axial direction with respect to the fixed system. an inner cam which is provided so that the drive clutch is engaged with the driven clutch by operating the outer cam that is engaged with the outer cam in a disengagement direction when the transmission of the driving force to the drive shaft is cut off; a holdout ring that is rotatable in the circumferential direction relative to the outer periphery of the outer cam and prevented from moving in the axial direction, and has a protrusion extending toward the inner cam; and a holdout ring that is integrally connected to the fixing system. and a stopper portion that engages with the protrusion when the outer cam is disengaged to prevent rotation of the holdout ring and maintain the disengaged position of the outer cam with respect to the inner cam, thereby forming an automatic clutch. It is something.

[Operation Cost] When the drive shaft is rotated so that the holdout ring rotates in the opposite direction from the position where the protruding part of the holdout ring is engaged with the collar part, the engagement between the stopper part and the protruding part is released. Restrictions on the resilient force applied to the drive clutch and outer cam are lifted. As a result, the outer cam begins to engage with the inner cam, and in response to this engagement, the inner cam is rotated in the rotational direction of the drive shaft. Therefore, the timing of engagement of the outer cam can be adjusted by rotating the inner cam, and the drive clutch disengages from the driven clutch in accordance with the engagement of the outer cam.
The driven member and the drive shaft are separated.

[Embodiment] A preferred embodiment of the automatic clutch of the present invention will be described below with reference to the accompanying drawings.

In Fig. 1, 1 is a drive shaft that transmits power from the differential to the wheels, 2 is a knuckle spindle that supports the drive shaft 1 via a bearing, and 4 is a wheel hub that supports the knuckle spindle 2. 5 is a sleeve, and 6 is a housing, which is supported via a bearing fitted on the outer circumference, and has a driven clutch 7 integrally formed on its inner peripheral surface.

As shown in FIG. 1, the knuckle spindle 2 is formed hollow along its axis, and the drive shaft 1 is rotatably supported in the hollow part via a bearing (not shown). . A wheel hub 4 is rotatably supported on the outer peripheral surface of the knuckle spindle 2 via a bearing (not shown), and a cylindrical housing 6 is provided on the outer end surface of the wheel hub 4 in the vehicle width direction. A hub cap 8 is further connected to the outer end surface of the housing 6 in the vehicle width direction. Although these connections are made by tightening bolts 9, other conventional means or the hub cap 8 and housing 6 may be made in one piece.

Therefore, rotating the housing 6 rotates the wheel hub 4. As shown in FIGS. 1 and 2, an annular driven clutch 7 for transmitting driving force is integrally fitted to the inner peripheral surface of the housing 6. Internal teeth 29a are formed for engaging a drive clutch 23, which will be described later, in a freely engaging and disengaging manner.

On the other hand, the free end (hub cap 8 side) of the drive shaft 1 accommodated in the housing 6 and the wheel hub 4 is reduced in diameter and has a stepped portion I.
f, and a spline portion 10 extending into the knuckle spindle 2 from the stepped portion 11 is formed on the outer circumferential surface of the drive workpiece. A sleeve 5 is fitted into this spline portion 10. The sleeve 5 has spline portions 12 and 13 formed along the axial direction on its inner and outer circumferential surfaces, and the spline portions 12 on the inner circumferential surface of the sleeve 5 are fitted into the spline portions 10 of the knuckle spindle 2. . 14 is a retaining ring for the shaft, 15 is a retaining ring for the hole, and 16 is a thrust washer, which are provided to prevent the sleeve 5 from moving in the axial direction with respect to the drive shaft 1.

Next, a configuration for connecting and separating the housing 6 and the drive shaft 1 will be explained.

The spline portion 13 on the outer peripheral surface of the sleeve 5 is provided with a return plate 22. Drive clutch 23. The outer cams 25 are spline-fitted, and spline portions 26°, 27, and 28 are formed on each inner peripheral surface. These are fitted so as to be movable along the axial direction. External teeth 29b are formed on the outer peripheral surface of the drive clutch 23 in order to engage and disengage the internal teeth 29a of the driven clutch 7. That is, the driven clutch 7 is moved to the hub cap 8 side, and the driven clutch 7 and the drive clutch 2
3 is connected, the drive shaft 1 is connected to the housing 6.
Conversely, when the wheels are separated, rotational force is transmitted from the housing 6, that is, the wheel hub 4 to the drive shaft 1.

Now, as a configuration for disengaging the drive clutch 23, the return spring 21. A retainer 18 is provided. The retainer 18 is the hub cap 811 of the sleeve 5.
1 has a slit 19 that allows the retainer 18 to freely close and close along the axial direction so as to be integrally fitted into the retainer ring groove 17 formed along the circumferential direction at the end of the retainer 18,
Further, a portion along the circumferential direction from the position of the ring groove 17 extends toward the hub cap 8 side, and is further folded back to extend radially outward. In other words, it is formed into a hat shape in cross section, the part extending in the circumferential direction becomes a cylinder, and the part extending outward in the radial direction becomes a collar part, which is fitted into the retainer ring groove 17. The part becomes the fitting hole 20, and by opening around the slit 19, it is possible to obtain a larger outer diameter than the attachment part of the sleeve 5, and after installation, it is formed so as to exhibit appropriate fitting strength. There is. In other words, this retainer 18 can have the original function as a retainer and the function as a snap ring (retaining ring) at the same time.

The return spring 21 is interposed between the retainer 18 and the return plate 22, and is configured to apply its elastic force in the direction of detachment (separation) of the drive clutch 23. The disengaged position is maintained unless a strong thrust force is applied in the connecting direction.

Reference numeral 30 designates a thrust bin which is provided within the drive clutch/y chain 23 so as to be movable along its axial direction, and one end of which is in contact with the return plate 22 and the other end is provided with abutment against the outer cam 25. . 24 is a lock spring, and the drive clutch 23 and outer cam 25r
It is installed in WJ. ＃Thrust bin 3 above
0, when the outer cam 25 is moved toward the hub cap 8flll, the return gear ring 21 is energized to operate the drive clutch 23 in the connecting direction, and the inner teeth 29a of the driven clutch 7 and the outer teeth 29b of the drive clutch 23 are connected. The purpose is to effectively use the elastic force of the lock spring 24 when the lock spring 24 engages with the plow.
Further, when the outer cam 25 loses its thrust force to the haptic cap 78 ( ) 11 , the drive clutch 23 is disengaged without being affected by the lock spring 24 on the return spring 21 .

In order to provide the outer cam 25 with a thrust function for the thrust bin 30 and the lock spring 24, the following configuration is used.

First, the knuckle spindle 2 is integrally provided with a key block 45 shown in FIGS. a fitting hole 46a whose end face extends radially inward as appropriate along the circumferential direction, and whose extending portion fits into the outer periphery of the knuckle spindle 2;
A seat portion 46 to be seated on a fixing system 60 for fixing the knuckle spindle 2 is formed at the same time.

This seat portion 46 is further formed with a key portion 47 that projects radially inward and is fitted into a key groove 48 of the knuckle spindle 2. This prevents rotation. Further, a ring portion 49 extending from the seat portion 46 toward the outer cam 25 is formed in the fitting hole 46a, and a ring groove 50 is formed on the outer periphery of the ring portion 49. Further, the seat portion 46 has a ring portion 49 on the outside of the ring portion 49.
Guide grooves 52 are formed at predetermined intervals along 9,
One end of a locking portion 51 formed by cutting out the ring portion 49 in the circumferential direction and one end of the guide groove 52 are located at approximately the same position.

Now, the reduced diameter portion 54 of the inner cam 40 is accommodated with a predetermined gap between the outer cylindrical portion, that is, the outer peripheral portion 45a, of the key block 45, and the ring portion 49, which is the inner cylindrical portion. . A locking piece 44 that is fitted into the guide groove 52 and rotated along the guide groove 52 is integrally provided on the differential side of the reduced diameter portion 54 . Furthermore,
As shown in FIG. 6, the reduced diameter portion 5 of the inner cam 40
A spring 58 is interposed between the outer periphery 45a of the key block 45 and the outer periphery 45a of the key block 45 to apply a resilient force in the opposite direction when the inner cam 40 is rotated. This spring 58 has hook portions 56a and 56 at both ends.
b, and the notch 6 of the reduced diameter portion 54 of the inner cam 40
After the hook part 56a is hooked on one end of the hook part 56 and the other hook part 56b is wound around the reduced diameter part 54 a plurality of times,
It is adapted to be hooked on the other end of the notch portion 65, and furthermore, both hook portions 56a and 56b are adapted to be hooked on both ends of the locking portion 51 of the ring portion 49, respectively. That is, when the inner cam 40 is rotated, the hook portion on the side opposite to the rotation direction becomes fixed, and the other hook portion is pulled by the reduced diameter portion 54.

This means that the rotation angle of the inner cam 40 can be increased by increasing the number of turns, and a spring with a predetermined return force can be accommodated in a small space. 57 is a snap ring.

Incidentally, cam teeth that can mesh with each other are arranged along the circumferential direction on the respective opposing surfaces of the inner cam 40 and the outer cam 25, and these cam teeth are arranged in a chevron shape in the circumferential direction. It is formed. That is,
When the outer cam 25 is prevented from rotating by the inner cam 40, the wedge action generated between the cam teeth causes the outer cam 25 to move toward the hub cap 8, and the drive clutch 23 is accordingly engaged. become. Therefore, the inner cam 40 and the outer cam 2
A member is required to maintain the engagement and disengagement of 5. These are the holdout ring 35 and the stopper portion 53.

The holdout ring 35 is formed from a cylindrical member,
A protrusion 36 rotatably fits into a fitting groove 34 formed along the outer periphery of the outer cam 23 on its inner circumferential surface.
In addition, on the end face on the inner cam 40 side, a plurality of protrusions 37 with a wide single step surface are formed along the circumferential direction extending toward the inner cam 40 side, and a droplet is provided between the protrusions 37. 59, and on the other hand, a second stage protrusion 38 is formed approximately in the middle of the protrusion 37 and further extends toward the inner cam 40 side. A slit 39 is formed in the axial direction of the holdout ring 35 in the same way as the retainer 18 described above, and this slit 39 allows a predetermined frictional force to be obtained against the outer cam 25 (see FIG. 2). Here, a tapered surface is formed between the drop portion 59 and the protruding portion 38 of the two-step surface.

In this embodiment, a plurality of stopper parts 53 are integrally provided on the outer peripheral surface of the key block 45, which is a fixed system, so as to stand up radially outward.

The relationship between the stopper portion 53 and the holdout ring 35 is such that when the outer cam 25 is engaged with the inner cam 40 and the drive clutch 23 is in a disengaged state, when rotational force is transmitted to the drive shaft 1, the inner cam 40 Since the outer cam 25 is detached, the stopper portion 53 engages with the corner 63 formed by the first stage protrusion 37 and the second stage protrusion 38 of the holdout ring 35 in order to maintain the detached position. It is supposed to be done. In other words, this engagement prevents the holdout ring 35 from rotating and only the outer cam 25 rotates. Further, since the axial surface of the corner portion 63 comes into contact with the stopper portion 53, the separation of the outer cam 25 from the inner cam 40 is maintained.

Contrary to this relationship, if the wheel hub 4 is made to rotate in the opposite direction when the inner cam 40 and the outer cam 25 are separated and the transmission of driving force from the differential to the drive shaft is cut off, holdout ring 3
The corner portion 63 of 5 is separated from the stopper portion 53 and rotated while sliding on the tapered surface. The outer cam 25 is moved in the engagement direction with respect to the inner cam 40 in accordance with this taper, and when engaged, the stopper portion 53 engages with the drop portion 59 (see Fig. 3). (See Figure 6).

The operation of the automatic clutch of the present invention will be explained below based on the accompanying drawings.

FIG. 1 shows the automatic clutch in the OFF state.

First, the operation when driving force is transmitted to the wheel hub 4 will be explained.

When a transfer (not shown) is switched to turn ON the side provided with the automatic clutch, rotational force is transmitted to the drive shaft 1 via a differential (not shown).

This rotation causes the cam teeth 4 of the inner cam 40 on the stationary side to
A knee force is generated between the outer cam 3 and the cam teeth 33 of the outer cam 25 on the driving side, and the outer cam 25 is separated from the inner cam 40. That is, the standstill state shown in FIG. 9 is shifted to the detached state shown in FIG. 10. At this time, the wedge force generated at the time of separation applies a force in the thrust direction to the holdout ring 35, so the holdout ring 35 is also rotated in the same direction as the outer cam 25, but this rotation is First stage protrusion 37 of out ring 35
and the end surface on the knuckle spindle 2 side.
It is blocked when it comes into contact with 9. With this operation, the thrust bin 30 acts on the return plate 22, overcomes the biasing force of the return spring 21, and moves the return spring 21 toward the retainer 18. This allows the lock spring 24 to move in accordance with the movement of the outer cam 25.
is not subjected to the biasing force of the return spring 21,
The drive clutch 23 is moved in the direction of the retainer 18.
At the timing when the external teeth 29b of the driven clutch 7 and the internal teeth 29a of the driven clutch 7 engage, the elastic force of the lock spring 24 acts all at once. This completes smooth engagement,
Driving force is transmitted to the wheel hub 4.

Next, the case of disengaging the automatic clutch, that is, switching from four wheels to two wheels, will be explained.

Turn off the transfer from the detached state shown in Figures 1 and 7.
When F is activated, power transmission to the drive shaft 1 is cut off. In this state, the vehicle, that is, the wheel hub 4 is slowly rotated in a direction opposite to the direction of travel before the transfer operation. As a result, the rotational force from the wheel hub 4 is transferred to the driven clutch 7, the sleeve 5. When transmitted to the outer cam 25, the holdout ring 35 also connects to the outer cam 2.
5, the stopper portion 53 relatively slides on the end surface of the inner cam 40 of the holdout ring 35 and is guided to the drop portion 59 formed by the first stage protrusion 37. Since the outer cam 25 is urged by the elastic force of the return spring 21 via the thrust bin 30, the outer cam 25 is moved in the direction of the inner cam 40 according to the taper angle of the -th stage protrusion 37. At this time, if the top surface of the cam teeth 33 of the outer cam 25 and the top surface of the cam teeth 43 of the inner cam 40 compete even slightly, the inner cam 40 will move in the direction of rotation as shown in FIGS. 8, 9, and 10. Since the cam teeth 33 and 43 are rotated, the cam teeth 33 and 43 can smoothly mesh with each other. This prevents the occurrence of abnormal noise due to interdental impact and abnormal wear of the cam teeth, and allows the drive clutch 7 to move from the drive clutch 2 to the drive clutch 2.
3 can be removed.

As described above, the wheel hub 4 can be freely rotated to allow the vehicle to run economically and to transmit powerful torque on rough roads.

[Effects of the Invention] As is clear from the above explanation, the automatic clutch of the present invention exhibits the following excellent effects.

(1) Since the inner cam can be rotated within a predetermined rotation range, the outer cam can be smoothly removed.

(2) Since the inner cam and the outer cam can be smoothly engaged and disengaged, abnormal noise and abnormal wear occurring between them can be prevented, and reliability and durability can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing a preferred embodiment of the automatic clutch of the present invention, FIG. 2 is a schematic perspective view of the automatic clutch of the present invention, and FIGS. 3 to 5 are schematic views showing a key block. FIG. 6 is a diagram showing a spring housed in the key block, FIGS. 7 to 10 are schematic diagrams showing engagement and disengagement between an inner cam and an outer cam, and FIGS. 11 and 12 are diagrams showing a conventional automatic clutch. It is a schematic diagram. In the figure, 1 is a drive shaft, 7 is a driven clutch, 23 is a drive clutch, 25 is an outer cam, 35 is a holdout ring, 38 is a protruding portion, 40 is an inner cam, and 53 is a stopper portion.

Claims (1)

[Claims] 1. A drive clutch that is rotated integrally with respect to the drive shaft and is movable along the axial direction, and is provided with an elastic force in the disengagement direction with respect to the driven clutch of the driven member. , is provided on the side of a fixed system that rotatably supports the drive shaft, so that it rotates integrally with the drive shaft and is movable along the axial direction, and moves in the disengagement direction of the driven clutch via the drive clutch. The outer cam is biased and has a predetermined rotation range with respect to the fixed system, is biased in the opposite direction of rotation, and is prevented from moving in the axial direction with respect to the fixed system. an inner cam that operates the outer cam that is engaged with the outer cam in a disengaging direction to engage the drive clutch with the driven clutch when the transmission of driving force to the drive shaft is cut off; and an outer periphery of the outer cam. a holdout ring that is provided so as to be rotatable in the circumferential direction and prevented from moving in the axial direction, and has a protrusion extending toward the inner cam side; and a holdout ring that is provided integrally with the fixing system; An automatic clutch comprising: a stopper part that engages with the protruding part to prevent rotation of the holdout ring when the outer cam is disengaged, and maintains the disengaged position of the outer cam relative to the inner cam.