JP6539496B2 - Free wheel hub mechanism - Google Patents

Description

  The present invention relates to a free wheel hub mechanism that switches between connection and disconnection of a driven wheel and a driven axle in conjunction with switching between a four-wheel drive state and a two-wheel drive state of a four-wheel drive vehicle.

  In a general four-wheel drive vehicle, the driving force output from the engine serving as the driving source through the transmission is transmitted to the propeller shaft on the main driving side (the rear side in the FR base) and the propeller on the driven side (the front side in the FR base) A transfer that distributes to the shaft is provided, and the transfer switches between the two-wheel drive (2WD) state and the four-wheel drive (4WD) state.

  That is, when traveling in a two-wheel drive state, the transfer transmits the driving force only to the main propeller shaft, thereby driving only the main wheels via the main axle connected to the main propeller shaft. When driving in a four-wheel drive mode, the transfer distributes and transmits the driving force to the driving propeller shaft and the driving propeller shaft, thereby driving the driving wheels and at the same time the driving propeller shaft. The driven wheels are also driven via the connected driven axles.

  Here, when the driven side wheel and the driven side axle are connected while traveling in the two-wheel drive state, the driven side axle and the driven side propeller shaft are rotated by the rotation of the driven side wheel. As a result, traveling resistance is increased and energy is wasted.

  For this reason, a modern four-wheel drive vehicle is provided with a free wheel hub mechanism for switching between connection and disconnection of the driven wheel and the driven axle between the driven wheel and the driven axle, and two-wheel drive When traveling in a state, by separating the driven wheel from the driven axle and setting it free, the driven axle and the driven propeller shaft are prevented from rotating, eliminating unnecessary energy consumption, and four-wheel drive When traveling in a state, the driven wheel and the driven axle are often connected to transmit the driving force to the driven wheel.

  For example, as shown in FIG. 9, the free wheel hub mechanism proposed in Patent Document 1 is a wheel hub that constitutes a part of the driven wheel 52 outside the axial end 51 a of the driven axle 51 in the radial direction. An outer gear 56 rotatably disposed integrally with the wheel hub 53 and the hub housing 55, inside the hub housing 55 disposed rotatably relative to the driven axle 51 and fixed by bolts 54 to the axially outer side of the wheel hub 53; A slide gear 57, which is slidably and relatively non-rotatably fitted to the shaft end 51a of the driven axle 51, is connected to the slide gear 57 capable of meshing with the outer gear 56, and the inside of the hub housing 55 is a two-wheel drive side negative A diaphragm 60 is provided to divide the pressure chamber 58 and the four-wheel drive side negative pressure chamber 59.

  A cylindrical spindle 61 is relatively rotatably fitted on the outer periphery of the shaft end 51 a of the driven side axle 51, and one end of the spindle 61 is fixed to the vehicle body (not shown). A bearing 62 is incorporated between them. Thus, the driven axle 51 and the wheel hub 53 are rotatably supported independently of each other.

  The spindle 61 fixed to the vehicle body is provided with negative pressure ports 63 communicated respectively to the negative pressure chambers 58 and 59, and each negative pressure port 63 is connected to a negative pressure pump (not shown) by a pipe 64. It is done.

  The outer gear 56 is formed at its inner periphery with internal teeth that mesh with the teeth of the outer periphery of the slide gear 57, and is splined to the inner periphery of the hub housing 55 at its outer periphery. The slide gear 57 is splined to the outer periphery of a portion of the shaft end 51 a of the driven axle 51 which protrudes from the spindle 61 at its inner peripheral portion.

  The diaphragm 60 is held at its central portion by an outer reinforcing plate 65 and an inner reinforcing plate 66, and is held at its outer peripheral portion by a cylindrical support member 67 and a diaphragm cover 68. The outer reinforcing plate 65 and the inner reinforcing plate 66 are formed of a press-formed product of a steel plate, and are integrated with the diaphragm 60 by caulking a rivet 69 penetrating the center of the diaphragm 60. Further, the inner reinforcing plate 66 is non-slidable and relatively rotatably attached to a portion axially outside the teeth of the slide gear 57 (hereinafter, this attached state is also referred to as “axially coupled”). The outer periphery of the diaphragm cover 68 is fixed to the axially outer portion of the outer periphery of the support member 67, and the support member 67 is splined to the inner periphery of the hub housing 55 at the axially inner portion thereof.

  An annular magnet 70 for attracting the outer reinforcing plate 65 in the axial direction is attached to the diaphragm cover 68, and the outer reinforcing plate 65 is attached to the slide gear 57 side between the diaphragm cover 68 and the outer reinforcing plate 65. A biasing coil spring 71 is incorporated.

  When the four-wheel drive vehicle is to be driven in the two-wheel drive mode, the two-wheel drive side negative pressure chamber 58 is decompressed via one negative pressure port 63 to elastically deform the diaphragm 60. The slide gear 57 connected in the axial direction is moved to a position where the engagement with the outer gear 56 is released, and the driven wheel 52 and the driven axle 51 are separated (state of FIG. 9) to travel in four-wheel drive state At the same time, the slide gear 57 is moved to a position where it engages with the outer gear 56 by reducing the pressure of the four-wheel drive side negative pressure chamber 59 via the other negative pressure port 63 and elastically deforming the diaphragm 60. It is made to connect 52 and the driven side axle shaft 51 (state of FIG. 10).

  Here, in the two-wheel drive state, as shown in FIG. 9, the outer reinforcing plate 65 of the diaphragm 60 is axially connected to the diaphragm 60 by being attracted to the magnet 70 attached to the diaphragm cover 68. The slide gear 57 is held at a position separated from the outer gear 56, and in the four-wheel drive state, as shown in FIG. 10, the outer reinforcing plate 65 is pressed against the coil spring 71 incorporated with the diaphragm cover 68. As a result, the slide gear 57 is held at a position where it engages with the outer gear 56. That is, in the two-wheel drive state, the attractive force of the magnet 70 is larger than the elastic force of the coil spring 71, and in the four-wheel drive state, the elastic force of the coil spring 71 is larger than the attractive force of the magnet 70. It is set.

JP 10-278621 A

  In the free wheel hub mechanism of Patent Document 1, switching between connection and disconnection of the driven side wheel and the driven side axle is automatically performed in conjunction with switching between the four-wheel drive state and the two-wheel drive state by transfer. It is like that.

  However, since the switching operation of the free wheel hub mechanism utilizes negative pressure, a negative pressure pump (that reduces the pressure in the two-wheel drive side negative pressure chamber or the four-wheel drive side negative pressure chamber) is generated. Problems such as a crack in the pipe connecting the negative pressure pump to the negative pressure port of the freewheel hub mechanism, the connection between the driven wheel and the driven axle can not be switched. was there.

  If the free wheel hub mechanism can not perform the switching operation, even if the transfer is in the two-wheel drive state, the vehicle will travel while wastefully consuming energy while the driven wheel and the driven axle are connected. However, even in the four-wheel drive state, the driven-side wheel and the driven-side axle can not be connected, and the two-wheel drive is forced to travel.

  Therefore, in the present invention, even if the free wheel hub mechanism of a four-wheel drive vehicle can not automatically switch between connection and disconnection of the driven wheel and the driven axle, the switching operation can be performed manually. As an issue.

  In order to solve the above-mentioned subject, the present invention makes the wheel hub which constitutes a part of driven side wheel relatively rotatable to the driven side axle outside the radial direction of the shaft end of the driven side axle of a four-wheel drive vehicle An outer gear integrally rotating with the wheel hub and the hub housing, and slidably and non-rotatably engaged with an axial end of the driven axle, inside the hub housing fixed to the wheel hub; A slide gear engageable with the outer gear, a diaphragm non-slidingly and relatively rotatably connected to the slide gear, and partitioning the inside of the hub housing into a two-wheel drive negative pressure chamber and a four-wheel drive negative pressure chamber When the four-wheel drive vehicle travels in a two-wheel drive mode, the slide gear is pushed out by reducing the pressure on the two-wheel drive side negative pressure chamber to elastically deform the diaphragm. The four-wheel drive negative pressure chamber when moving the four-wheel drive vehicle in the four-wheel drive state by moving the driven wheel to the position where the engagement with the gear is released and separating the driven wheel from the driven axle In the free wheel hub mechanism, the slide gear is moved to a position where it engages with the outer gear by elastically reducing the pressure of the diaphragm to elastically deform the diaphragm, thereby connecting the slide gear to the driven wheel and the driven axle. Means are provided for manually moving between the meshing position with the outer gear and the position where the meshing is released.

  That is, the slide gear is automatically moved by providing means for manually moving the slide gear attached to the driven axle between the meshing position with the outer gear attached to the driven wheel and the position where the meshing is released. Even when movement can not be performed, connection and disconnection of the driven wheel and the driven axle can be switched.

  As a means for moving the slide gear manually, one end of a cylindrical operation piece axially opposed to the axial end of the driven axle is rotatably fitted in a mounting hole provided in the hub housing A sleeve slidably fitted on the outer periphery of the other end of the operation piece is supported slidably and relatively non-rotatably with respect to the operation piece, and the sleeve is provided with an engagement groove extending obliquely with respect to the axial direction In addition, the operation piece is provided with a pin inserted into the engagement groove of the sleeve, and when the operation piece is rotated, the sleeve engages with the slide gear due to the engagement between the pin of the operation piece and the engagement groove of the sleeve. It is possible to adopt one that moves in the axial direction integrally.

  In the above configuration, the flange portion is provided on one end side of the operation piece, and the mounting hole of the hub housing is provided with a step surface axially opposed to the flange portion of the operation piece, and the step surface and the operation piece An elastic seal member is disposed between the flange and the flange portion, and is disposed between the wave spring fixed on the inner periphery of the hub housing or between the flange portion of the operation piece and the retaining ring fixed on the inner periphery of the hub housing. The resilient seal member may be compressed by pressing the flange portion of the operation piece in the axial direction by the disc spring. In this way, it is possible to reliably prevent a drop in air tightness by providing the mounting hole in the hub housing, and stably switch between connection and disconnection of the driven wheel and the driven axle by the elastic deformation of the diaphragm. Can.

  Further, if at least one of the pin of the operation piece and the engagement groove of the sleeve is subjected to surface treatment for reducing frictional resistance, switching between connection and disconnection of the driven wheel and the driven axle can be performed more smoothly. Become.

  As described above, in the free wheel hub mechanism of the present invention, the slide gear attached to the driven axle of the four-wheel drive vehicle is manually moved to mesh with the outer gear attached to the driven wheel, or the engagement is released. Since the slide gear can not be moved automatically, the connection and disconnection of the driven wheel and the driven axle can be switched.

  Therefore, in a four-wheel drive vehicle incorporating this free wheel hub mechanism, even in an emergency such as when the switching operation between the connection and disconnection of the driven wheel and the driven axle can not be performed automatically, the switching operation is performed as the operating condition By doing so manually, operation can be performed in the same manner as normal.

Schematic block diagram of a four-wheel drive vehicle incorporating the free wheel hub mechanism of the embodiment Longitudinal front view of the free wheel hub mechanism of FIG. 1 The vertical front view which expanded the principal part of FIG. 2 An exploded perspective view of the main part of FIG. 3 An exploded perspective view of another main part of FIG. 3 Longitudinal front view explaining automatic operation of free wheel hub mechanism corresponding to FIG. 3 Longitudinal front view explaining manual operation of free wheel hub mechanism corresponding to FIG. 3 Longitudinal front view of the main part showing a modification of the sealing means of the free wheel hub mechanism of FIG. 2 Longitudinal front view of conventional free wheel hub mechanism Longitudinal front view explaining the operation of the free wheel hub mechanism of FIG. 9

  Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 8. FIG. 1 schematically shows the configuration of a four-wheel drive vehicle incorporating the free wheel hub mechanism of the embodiment. This four-wheel drive vehicle is an FR-based vehicle and includes an engine 1 as a drive source, a transmission 2 that converts and outputs the rotation of the engine 1, and a transfer 3 connected to the output side of the transmission 2 Is equipped.

  The transfer 3 has a switching mechanism 4 for switching between a two-wheel drive (2WD) state and a four-wheel drive (4WD) state, and a transfer lever 5 for operating the switching mechanism 4. The rear propeller shaft 6 and the front propeller shaft 7 are connected to the transfer 3 respectively, the rear propeller shaft 6 is provided with the rear differential 8, and the front propeller shaft 7 is provided with the front differential 9. ing.

  The rear differential shaft 8 is connected to the rear axle (main driving axle) 10, and the front differential 9 is connected to the front axle 11 (following axle). Wheels (primary wheels) 12 are attached, and front wheels (following wheels) 13 are attached to the left and right ends of the front axle 11 via a free wheel hub mechanism 14.

  This four-wheel drive vehicle has the configuration described above, and when the two-wheel drive state is selected by operating the transfer lever 5 of the transfer 3, the drive in which the switching mechanism 4 is output from the engine 1 via the transmission 2 By transmitting the force only to the rear propeller shaft 6, only the left and right rear wheels 12 are driven via the rear differential 8 and the rear axle 10.

  On the other hand, when the four-wheel drive state is selected by the transfer lever 5, the switching mechanism 4 distributes and transmits the driving force to the rear propeller shaft 6 and the front propeller shaft 7 to drive the left and right rear wheels 12 simultaneously. The front left and right front wheels 13 are also driven via the front differential 9, the front axle 11, and the free wheel hub mechanism 14.

  The freewheel hub mechanism 14 automatically switches between connection and disconnection of the front wheel 13 and the front axle 11 in conjunction with switching between the four-wheel drive state and the two-wheel drive state by the transfer 3. There is.

  The basic configuration of the free wheel hub mechanism 14 of the embodiment incorporated in the four-wheel drive vehicle described above is the same as the conventional one shown in FIGS. 9 and 10 described above.

  That is, as shown in FIGS. 2 and 3, the free wheel hub mechanism 14 has the wheel hub 15 that constitutes a part of the front wheel 13 and the front axle 11 on the radially outer side of the shaft end 11 a of the front axle 11. The outer gear 18, which rotates integrally with the wheel hub 15 and the hub housing 17, and the shaft end of the front axle 11 are disposed inside the hub housing 17 which is disposed relatively rotatably and is fixed to the wheel hub 15 axially outward with bolts 16 A slide gear 19 slidably and relatively non-rotatably fitted to 11a and coupled to a slide gear 19 capable of meshing with an outer gear 18, and the inside of the hub housing 17 as a two-wheel drive side negative pressure chamber 20 and a four-wheel drive side The negative pressure chamber 21 and the diaphragm 22 are provided.

  A cylindrical spindle 23 is relatively rotatably fitted on the outer periphery of the shaft end 11a of the front axle 11, and one end of the spindle 23 is fixed to a vehicle body (not shown), and the spindle 23 and the wheel hub 15 A bearing 24 is incorporated between them. Thus, the front axle 11 and the wheel hub 15 are rotatably supported independently of each other.

  The spindle 23 fixed to the vehicle body is provided with a negative pressure port 25 communicating with each negative pressure chamber 20, 21. Each negative pressure port 25 is connected to a negative pressure pump (not shown) by a pipe 26. It is done. In order to ensure the airtightness of the negative pressure path connecting each negative pressure chamber 20, 21 and the negative pressure port 25, the negative pressure path to the two-wheel drive side negative pressure chamber 20 and the four-wheel drive side negative pressure A first seal member 27 for sealing between the negative pressure path to the chamber 21, a second seal member 28 for sealing between the negative pressure path for the two-wheel drive side negative pressure chamber 20 and the outside, and four wheels A third seal member 29 is provided which seals between the negative pressure path to the drive side negative pressure chamber 21 and the outside.

  The outer gear 18 is formed at its inner periphery with internal teeth that mesh with teeth on the outer periphery of the slide gear 19 and is splined to the inner periphery of the hub housing 17 at its outer periphery. The slide gear 19 is splined to the outer periphery of a portion of the shaft end 11 a of the front axle 11 which protrudes from the spindle 23 at the inner peripheral portion thereof.

  The diaphragm 22 is held between the outer reinforcing plate 30 and the inner reinforcing plate 31 at its central portion, and is held between the cylindrical supporting member 32 and the diaphragm cover 33 at its outer peripheral portion. The outer reinforcing plate 30 and the inner reinforcing plate 31 are made of a press-formed product of a steel plate, and are integrated with the diaphragm 22 by caulking a rivet 34 penetrating the center of the diaphragm 22. Further, the inner reinforcing plate 31 is non-slidable and relatively rotatably attached to a portion axially outside the teeth of the slide gear 19. The outer periphery of the diaphragm cover 33 is fixed to the axially outer portion of the outer periphery of the support member 32, and the support member 32 is splined to the inner periphery of the hub housing 17 at the axially inner portion of the outer periphery.

  A fourth seal member for sealing between the negative pressure path to the two-wheel drive side negative pressure chamber 20 and the negative pressure path to the four-wheel drive side negative pressure chamber 21 between the support member 32 and the outer gear 18 35 are provided. In addition, a coil spring 36 is incorporated between the diaphragm cover 33 and the outer reinforcing plate 30 for urging the outer reinforcing plate 30 toward the slide gear 19.

  The hub housing 17 is provided with a mounting hole 37 penetrating an end portion on the axial outer side, and one end portion of a cylindrical operation piece 38 is rotatably fitted in the mounting hole 37. A flange portion 38a is provided on one end side of the operation piece 38, and a stepped surface 37a axially opposed to the outer surface of the flange portion 38a of the operation piece 38 is provided in the mounting hole 37 of the hub housing 17. An O-ring (elastic seal member) 39 is disposed in an annular groove provided on the outer surface of the flange portion 38 a of the operation piece 38 in a state in which one end side in the axial direction is protruded.

  Then, the outer peripheral portion of a substantially annular wave spring 40 (see FIG. 4) is fitted and fixed in an annular groove provided on the inner periphery of the hub housing 17, and the flange portion 38 a of the operation piece 38 is axially The O-ring 39 is compressed by pressing outward. Thus, the hub housing 17 can ensure sufficient air tightness even if the mounting hole 37 is provided. In addition, the O-ring 39 also plays a role of providing appropriate rotation resistance to the operation piece 38 to prevent the rotation of the operation piece 38 due to vibration or the like during traveling.

  A pair of substantially semicircular recessed portions 38b are provided on one end surface of the operation piece 38, and an operating portion 38c extending in the radial direction is formed between the both recessed portions 38b (see FIG. 4). The other end of the operation piece 38 is axially opposed to the shaft end 11a of the front axle 11 with the rivet 34 and the like interposed therebetween, and the large diameter portion of the two-step cylindrical sleeve 41 slides on the outer periphery thereof. It is fitted in freely.

  In the sleeve 41, an annular magnet 42 is attached to a step surface facing the outer reinforcing plate 30 of the diaphragm 22. Further, as shown in FIGS. 4 and 5, two axially extending protrusions 41 a are provided on the outer peripheral surface of the large diameter portion of the sleeve 41, and each of the protrusions 41 a is an inner cylinder of the diaphragm cover 33. The sleeve 41 is slidably and relatively non-rotatably supported relative to the operation piece 38 by being slidably fitted in an axial groove 33b provided on the inner circumferential surface of the portion 33a. The large diameter portion of the sleeve 41 is provided with two engagement grooves 41b extending obliquely with respect to the axial direction, and the outer peripheral surface of the other end of the operation piece 38 is provided on each engagement groove 41b of the sleeve 41. A pin 43 to be inserted is provided. Thereby, when the operation piece 38 is rotated, the sleeve 41 is guided by the diaphragm cover 33 to move in the axial direction by the engagement of the pin 43 of the operation piece 38 and the engagement groove 41b of the sleeve 41. ing.

  Here, in order to smoothly move the sleeve 41 in the axial direction, each engagement groove 41 b of the sleeve 41 is subjected to surface treatment for reducing frictional resistance. The surface treatment for reducing the frictional resistance may be applied to both the engaging groove 41b of the sleeve 41 and the pin 43 of the operation piece 38, or may be applied only to the pin 43 of the operation piece 38. .

  Next, the operation of the free wheel hub mechanism 14 will be described. Usually, when traveling a four-wheel drive vehicle in a two-wheel drive state, the pressure on the two-wheel drive side negative pressure chamber 20 is automatically reduced via one negative pressure port 25 to elastically deform the diaphragm 22, The slide gear 19 axially connected to the diaphragm 22 is moved to a position where the engagement with the outer gear 18 is released, and the front wheel 13 and the front axle 11 are separated (state of FIG. 3). Further, when traveling in the four-wheel drive state, the slide gear 19 is outer gear by automatically reducing the pressure on the four-wheel drive side negative pressure chamber 21 via the other negative pressure port 25 to elastically deform the diaphragm 22. The front wheel 13 and the front axle 11 are connected by moving to a position where they mesh with the wheel 18 (the state of FIG. 6).

  Here, in the two-wheel drive state, as shown in FIG. 3, the outer reinforcing plate 30 of the diaphragm 22 is axially connected to the diaphragm 22 by being attracted to the magnet 42 attached to the sleeve 41. The slide gear 19 is held at a position separated from the outer gear 18, and in the four-wheel drive state, as shown in FIG. 6, the outer reinforcing plate 30 is pushed by a coil spring 36 incorporated between the diaphragm cover 33 and the same. Thus, the slide gear 19 is held at a position where it engages with the outer gear 18. That is, in the two-wheel drive state, the attractive force of the magnet 42 is larger than the elastic force of the coil spring 36, and in the four-wheel drive state, the elastic force of the coil spring 36 is larger than the attractive force of the magnet 42. It is set.

  On the other hand, in the free wheel hub mechanism 14, when switching between connection and disconnection between the front wheel 13 and the front axle 11 can not be automatically performed, for example, the two-wheel drive negative pressure chamber 20 or the four-wheel drive negative If a failure occurs such as a failure of the negative pressure pump that decompresses the pressure chamber 21 or a crack of the pipe 26 that connects the negative pressure pump and each negative pressure port 25, the switching operation is manually performed as follows. It can be carried out.

  That is, first, as shown in FIG. 3, when the front wheel 13 and the front axle 11 are disconnected (two-wheel drive state), when the automatic switching operation using negative pressure can not be performed, the operation piece The sleeve 41 engaged with the operation piece 38 is axially moved (advanced) by manually rotating the operation portion 38c of 38 in a predetermined direction, and the sleeve 41 pushes and moves the diaphragm 22 so that the diaphragm 22 is axially moved. The slide gear 19 connected in the above manner can be moved to a position where it engages with the outer gear 18 (the state of FIG. 7), and the front wheel 13 and the front axle 11 can be connected.

  Further, as shown in FIG. 6, when the front wheel 13 and the front axle 11 are connected (four-wheel drive state) and automatic switching operation can not be performed, the operation piece 38 is temporarily set in a predetermined direction. After the sleeve 41 is advanced until it abuts against the outer reinforcing plate 30 of the diaphragm 22 by rotation, the magnet 42 attached to the sleeve 41 is brought into a state of attracting the outer reinforcing plate 30 (state of FIG. 7) By rotating the operation piece 38c in the reverse direction, the sleeve 41 is retracted together with the diaphragm 22 and the slide gear 19, and the slide gear 19 is moved to a position where the engagement with the outer gear 18 is released (state of FIG. 3) The front wheel 13 and the front axle 11 can be disconnected.

  As described above, the free wheel hub mechanism 14 moves the slide gear 19 attached to the front axle 11 of the four-wheel drive vehicle by manually rotating the operation piece 38, and the outer gear attached to the front wheel 13. Since it is possible to mesh with the gear wheel 18 or to release the meshing, connection and disconnection of the front wheel 13 and the front axle 11 can be switched even when the slide gear 19 can not be moved automatically.

  Therefore, in a four-wheel drive vehicle incorporating this free wheel hub mechanism 14, even in an emergency such as when the switching operation between the connection and disconnection of the front wheel 13 and the front axle 11 can not be performed automatically, the switching operation is performed as the driving condition According to the above, the operation can be performed in the same manner as the normal operation except that it takes a little time at the time of the manual switching by performing it manually.

  In the embodiment described above, a wave spring which presses the flange portion 38a of the operation piece 38 axially outward in order to compress the O-ring 39 disposed between the hub housing 17 and the operation piece 38 to ensure airtightness. 40 is provided, but as shown in FIG. 8, a snap ring 44 is fitted and fixed in an annular groove on the inner periphery of the hub housing 17 and disposed between the snap ring 44 and the flange portion 38 a of the operation piece 38. The flange portion 38 a of the operation piece 38 may be pressed axially outward by the disc spring 45.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the meaning described above but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

  For example, in the embodiment, the slide gear is moved by manually turning the operation piece, but the slide gear may be moved between the meshing position with the outer gear and the position at which the meshing is released. Any means may be adopted if possible.

11 front axle (following axle)
11a shaft end 13 front wheel (following wheel)
14 free wheel hub mechanism 15 wheel hub 17 hub housing 18 outer gear 19 slide gear 20 2 wheel drive side negative pressure chamber 21 4 wheel drive side negative pressure chamber 22 diaphragm 36 coil spring 37 attachment hole 37a step surface 38 operation piece 38a flange portion 39 O ring (elastic seal member)
40 wave spring 41 sleeve 41 b engagement groove 42 magnet 43 pin 44 snap ring 45 disc spring

Claims (4)

A hub housing is disposed radially outward of the shaft end of a driven axle of a four-wheel drive vehicle, and a wheel hub constituting a part of a driven wheel is rotatably disposed relative to the driven axle and fixed to the wheel hub Inside, an outer gear integrally rotating with the wheel hub and the hub housing, a slide gear slidably and relatively non-rotatably fitted to the shaft end of the driven axle, and the slide gear engageable with the outer gear; There is provided a diaphragm which is non-slidable and relatively rotatably connected to the gear and which divides the inside of the hub housing into a two-wheel drive side negative pressure chamber and a four-wheel drive side negative pressure chamber.
When traveling the four-wheel drive vehicle in the two-wheel drive state, the two-wheel drive side negative pressure chamber is decompressed to elastically deform the diaphragm, so that the slide gear is disengaged from the outer gear. And move the driven wheel and the driven axle separately.
When traveling the four-wheel drive vehicle in the four-wheel drive state, the slide gear is moved to a position where it engages with the outer gear by reducing the pressure on the four-wheel drive side negative pressure chamber and elastically deforming the diaphragm. In a free wheel hub mechanism adapted to connect a driven wheel and a driven axle,
There is provided means for manually moving the slide gear between a meshing position with the outer gear and a position at which the meshing is released ,
The means for manually moving the slide gear is rotatably fitted at one end of a cylindrical operation piece axially opposed to the axial end of the driven axle into a mounting hole provided in the hub housing. A sleeve slidably fitted on the outer periphery of the other end of the operation piece is slidably and relatively non-rotatably supported with respect to the operation piece, and the sleeve is provided with an engagement groove extending obliquely with respect to the axial direction. Providing the operating piece with a pin inserted into the engagement groove of the sleeve;
When rotating the operation lever, the engagement between the engaging groove of the pin and the sleeve of the operating piece, you characterized in that said sleeve is obtained so as to move in the axial direction together with the slide gears -free wheel hub mechanism. A flange portion is provided on one end side of the operation piece, and a step surface opposed in the axial direction to the flange portion of the operation piece is provided in the mounting hole of the hub housing, and between the step surface and the flange portion of the operation piece arranging an elastic seal member, the inner periphery is fixed a wave spring of the hub housing, to press the flange portion of the operation piece in the axial direction, according to claim 1, characterized in that compressing the elastic sealing member Freewheel hub mechanism as described in. A flange portion is provided on one end side of the operation piece, and a step surface opposed in the axial direction to the flange portion of the operation piece is provided in the mounting hole of the hub housing, and between the step surface and the flange portion of the operation piece The flange portion of the operation piece is axially pressed by a disc spring disposed between the flange portion of the operation piece and the snap ring fixed to the inner periphery of the hub housing. The free wheel hub mechanism according to claim 1 , wherein the elastic seal member is compressed. The free wheel hub mechanism according to any one of claims 1 to 3 , wherein at least one of the pin of the operation piece and the engagement groove of the sleeve is subjected to a surface treatment for reducing frictional resistance.

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