JP2016215777A - Free wheel hub mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manually perform a switching operation even if a free wheel hub mechanism of a four-wheel device vehicle cannot perform automatically the switching of the connection and disconnection of driven-side wheels and driven-side axles.SOLUTION: One end part of a cylindrical operation piece 38 which opposes an axial end part 11a of a front-side axle (driven-side axle) 11 in an axial direction is fit into an attachment hole 37 formed at a hub housing 17 so as to be turnable, a sleeve 41 which is slidably fit into an external periphery of the operation piece 38 at the other side is slidably and non-rotatably supported to the operation piece 38, an engagement groove 41b which obliquely extends to the axial direction is formed at the sleeve 41, a pin 43 which is inserted into the engagement groove 41b of the sleeve 41 is arranged at the operation piece 38, and a slide gear 19 attached to the front-side axle 11 can be engaged with an outer gear 18 attached to a front wheel (driven-side wheel) 13, or released therefrom by moving the sleeve 41 to the axial direction by manually turning the operation piece 38.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a freewheel 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 typical four-wheel drive vehicle, the driving force output from the engine that is the driving source via the transmission is transmitted to the propeller shaft on the main driving side (rear side on the FR base) and the propeller on the driven side (front side on the FR base). A transfer distributed to the shaft is provided, and switching between the two-wheel drive (2WD) state and the four-wheel drive (4WD) state is performed by the transfer.

  In other words, when driving in a two-wheel drive state, the transfer transmits driving force only to the main propeller shaft so that only the main wheels are driven via the main axle connected to the main propeller shaft. When driving in a four-wheel drive state, the transfer distributes the driving force to the driving-side propeller shaft and the driven-side propeller shaft to transmit the driving-side wheel, and at the same time to the driven-side propeller shaft. The driven wheel is also driven through the connected driven axle.

  Here, when the vehicle is traveling in a two-wheel drive state, if the driven wheel and the driven axle are connected, the driven axle and the driven propeller shaft are rotated by the rotation of the driven wheel. Therefore, running resistance increases and energy is wasted.

  For this reason, a recent 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. When driving in a state, the driven-side wheel is separated from the driven-side axle so as to be in a free state, so that the driven-side axle and the driven-side propeller shaft are prevented from rotating, and wasteful energy consumption is eliminated. When trying to travel in a state, the driven wheel and the driven axle are often connected so that the driving force is transmitted to the driven wheel.

  For example, the freewheel hub mechanism proposed in Patent Document 1 is a wheel hub that forms a part of the driven wheel 52 on the radially outer side of the shaft end portion 51a of the driven axle 51 as shown in FIG. 53, an outer gear 56 that rotates integrally with the wheel hub 53 and the hub housing 55, and is disposed in a hub housing 55 that is disposed so as to be rotatable relative to the driven-side axle 51 and is fixed to the outer side in the axial direction of the wheel hub 53 with bolts 54. The shaft end 51a of the driven-side axle 51 is slidably and relatively non-rotatably fitted, is connected to the slide gear 57 that can mesh with the outer gear 56, and the slide gear 57. The inside of the hub housing 55 is negative on the two-wheel drive side. A diaphragm 60 is provided for partitioning into a pressure chamber 58 and a four-wheel drive negative pressure chamber 59.

  A cylindrical spindle 61 is fitted on the outer periphery of the shaft end 51a of the driven-side axle 51 so as to be relatively rotatable. One end of the spindle 61 is fixed to a vehicle body (not shown), and the spindle 61 and the wheel hub 53 are fixed. Between the two, a bearing 62 is incorporated. As a result, the driven-side 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 a negative pressure port 63 communicating with each of 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. Has been.

  The outer gear 56 has inner teeth that engage with the outer teeth of the slide gear 57 on its inner periphery, and is splined to the inner periphery of the hub housing 55 at the outer periphery. The slide gear 57 is splined to the outer periphery of the portion of the shaft end portion 51a of the driven-side axle 51 protruding from the spindle 61 at the inner periphery thereof.

  The diaphragm 60 is sandwiched between an outer reinforcing plate 65 and an inner reinforcing plate 66 at the center, and is sandwiched between a cylindrical support member 67 and a diaphragm cover 68 at the outer peripheral portion. The outer reinforcing plate 65 and the inner reinforcing plate 66 are made of a steel plate press-molded product, and are integrated with the diaphragm 60 by caulking a rivet 69 that passes through the center of the diaphragm 60. The inner reinforcing plate 66 is attached to a portion outside the teeth in the axial direction with respect to the teeth of the slide gear 57 so as not to be slidable and relatively rotatable (hereinafter, this attached state is also referred to as “coupled in the axial direction”). The outer periphery of the diaphragm cover 68 is fixed to the outer periphery of the support member 67 in the axial direction, and the support member 67 is splined to the inner periphery of the hub housing 55 at the outer periphery in the axial direction.

  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. An energizing coil spring 71 is incorporated.

  When a four-wheel drive vehicle is driven in a two-wheel drive state, the diaphragm 60 is elastically deformed by reducing the pressure of the two-wheel drive side negative pressure chamber 58 via one negative pressure port 63, so that the diaphragm 60 The slide gear 57 connected in the axial direction is moved to a position where the meshing with the outer gear 56 is released, and the driven wheel 52 and the driven axle 51 are separated (the state shown in FIG. 9), and the vehicle runs in a four-wheel drive state. When the four-wheel drive-side negative pressure chamber 59 is decompressed via the other negative pressure port 63 and the diaphragm 60 is elastically deformed, the slide gear 57 is moved to a position where it meshes with the outer gear 56 to drive the driven wheel. 52 and the driven-side axle 51 are connected (state shown in FIG. 10).

  Here, in the two-wheel drive state, as shown in FIG. 9, the outer reinforcing plate 65 of the diaphragm 60 is attracted to the magnet 70 attached to the diaphragm cover 68, thereby being connected to the diaphragm 60 in the axial direction. The slide gear 57 is held at a position separated from the outer gear 56. In the four-wheel drive state, the outer reinforcing plate 65 is pushed by the coil spring 71 incorporated between the diaphragm cover 68 and the outer peripheral plate 65 as shown in FIG. As a result, the slide gear 57 is held at a position where the slide gear 57 meshes with the outer gear 56. That is, the attractive force of the magnet 70 is larger than the elastic force of the coil spring 71 in the two-wheel drive state, and the elastic force of the coil spring 71 is larger than the attractive force of the magnet 70 in the four-wheel drive state. Is set.

Japanese Patent Laid-Open No. 10-278621

  In the free wheel hub mechanism disclosed in Patent Document 1, the connection between the four-wheel drive state and the two-wheel drive state by transfer is automatically switched between connection and disconnection of the driven wheel and the driven axle. I am doing so.

  However, since the switching operation of the free wheel hub mechanism uses negative pressure, a negative pressure pump that generates the negative pressure (depressurizes the two-wheel drive side negative pressure chamber or the four-wheel drive side negative pressure chamber). Problems such as failure of the pipe or cracks in the pipe connecting the negative pressure pump and the negative pressure port of the freewheel hub mechanism, it becomes impossible to switch between connection and disconnection of the driven wheel and the driven axle was there.

  If the freewheel hub mechanism cannot perform the switching operation, even if the transfer is in a two-wheel drive state, the driven wheel and the driven axle are connected and the vehicle is traveling while consuming energy wastefully. However, even in the four-wheel drive state, the driven-side wheel and the driven-side axle cannot be connected, and it is forced to travel with two-wheel drive.

  Therefore, the present invention enables manual switching operation even when the freewheel hub mechanism of a four-wheel drive vehicle cannot automatically switch between connection and disconnection of a driven wheel and a driven axle. Is an issue.

  In order to solve the above-described problems, the present invention enables a wheel hub constituting a part of a driven wheel to be rotated relative to a driven axle on the radially outer side of a shaft end portion of a driven axle of a four-wheel drive vehicle. An outer gear that rotates integrally with the wheel hub and the hub housing, and a shaft end portion of the driven-side axle that is slidable and relatively non-rotatably fitted inside the hub housing fixed to the wheel hub, A slide gear that can mesh with the outer gear, and a diaphragm that is connected to the slide gear so as to be non-slidable and relatively rotatable, and partitions the interior of the hub housing into a two-wheel drive-side negative pressure chamber and a four-wheel drive-side negative pressure chamber; When the four-wheel drive vehicle is driven in a two-wheel drive state, the slide gear is moved out by depressurizing the two-wheel drive side negative pressure chamber and elastically deforming the diaphragm. When the four-wheel drive vehicle is driven in a four-wheel drive state by moving to a position where the meshing with the gear is released to separate the driven wheel and the driven axle, the four-wheel drive negative pressure chamber In the free wheel hub mechanism in which the driven gear and the driven axle are connected by moving the slide gear to a position where it engages with the outer gear by elastically deforming the diaphragm by reducing the pressure of the slide gear, Means for manually moving between an engagement position with the outer gear and a position at which the engagement is released is provided.

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

  As means for manually moving the slide gear, one end of a cylindrical operation piece facing the shaft end of the driven-side axle in the axial direction is rotatably fitted in a mounting hole provided in the hub housing. The sleeve that is slidably fitted to the outer periphery of the other end of the operation piece is supported so as to be slidable and non-rotatable relative to the operation piece, and the sleeve is provided with an engagement groove extending obliquely with respect to the axial direction. In addition, when the operation piece is provided with a pin to be inserted into the engagement groove of the sleeve and the operation piece is rotated, the sleeve and the slide gear are engaged by 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, a flange portion is provided on one end side of the operation piece, and a step surface facing the flange portion of the operation piece in the axial direction is provided in the mounting hole of the hub housing. An elastic seal member is arranged between the flange portion of the hub housing and a wave spring fixed to the inner periphery of the hub housing or between a flange portion of the operation piece and a retaining ring fixed to the inner periphery of the hub housing. The elastic seal member may be compressed by pressing the flange portion of the operation piece in the axial direction with the disc spring. In this way, it is possible to reliably prevent a decrease in airtightness due to the mounting holes in the hub housing, and to stably switch between connection and disconnection of the driven wheel and the driven axle due to elastic deformation of the diaphragm. Can do.

  In addition, if at least one of the pin of the operation piece and the engagement groove of the sleeve is subjected to a surface treatment that reduces frictional resistance, the connection and disconnection of the driven wheel and the driven axle can be switched more smoothly. Become.

  As described above, the freewheel hub mechanism of the present invention manually moves the slide gear attached to the driven axle of the four-wheel drive vehicle so as to mesh with or release the outer gear attached to the driven wheel. Therefore, even when the slide gear cannot be moved automatically, connection and disconnection of the driven wheel and the driven axle can be switched.

  Therefore, in a four-wheel drive vehicle incorporating this freewheel hub mechanism, the switching operation can be performed even in an emergency where switching between connection and disconnection of the driven wheel and driven axle cannot be performed automatically. By performing manually according to the above, it is possible to operate as usual.

Schematic configuration diagram of a four-wheel drive vehicle incorporating the freewheel hub mechanism of the embodiment Longitudinal front view of the freewheel hub mechanism of FIG. A longitudinal front view enlarging the main part of FIG. 3 is an exploded perspective view of the main part of FIG. The disassembled perspective view of another principal part of FIG. A longitudinal front view for explaining the automatic operation of the freewheel hub mechanism corresponding to FIG. A longitudinal front view for explaining the manual operation of the freewheel hub mechanism corresponding to FIG. FIG. 2 is a longitudinal front view of the main part showing a modification of the sealing means of the freewheel hub mechanism of FIG. Longitudinal front view of a conventional freewheel hub mechanism FIG. 9 is a longitudinal front view for explaining the operation of the freewheel hub mechanism of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 schematically shows the configuration of a four-wheel drive vehicle incorporating the freewheel hub mechanism of the embodiment. The four-wheel drive vehicle is an FR-based vehicle, and includes an engine 1 as a drive source, a transmission 2 that converts the rotation of the engine 1 and outputs, and a transfer 3 that is connected to the output side of the transmission 2. It has.

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

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

  This four-wheel drive vehicle has the above-described configuration. When the two-wheel drive state is selected by operating the transfer lever 5 of the transfer 3, 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, thereby simultaneously driving the left and right rear wheels 12. The left and right front wheels 13 are also driven through the front differential 9, the front axle 11, and the freewheel 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. Yes.

  The basic configuration of the freewheel hub mechanism 14 of the embodiment incorporated in the above four-wheel drive vehicle 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 includes a 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 portion 11 a of the front axle 11. An outer gear 18 that rotates relative to the wheel hub 15 and is integrally rotated with the hub housing 17 and a shaft end portion of the front axle 11 are disposed in a hub housing 17 that is disposed so as to be relatively rotatable and is fixed to the wheel hub 15 with an bolt 16 on the outer side in the axial direction. 11a is slidably fitted to the outer gear 18 so as to be slidable and relatively non-rotatable, and is connected to the slide gear 19, and the inside of the hub housing 17 is connected to the two-wheel drive side negative pressure chamber 20 and the four-wheel drive side. A diaphragm 22 for partitioning with the negative pressure chamber 21 is provided.

  A cylindrical spindle 23 is fitted to the outer periphery of the shaft end portion 11a of the front axle 11 so as to be relatively rotatable, and one end portion of the spindle 23 is fixed to a vehicle body (not shown), and the spindle 23, the wheel hub 15, A bearing 24 is incorporated in between. Thereby, 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 of the negative pressure chambers 20 and 21, and each negative pressure port 25 is connected to a negative pressure pump (not shown) by a pipe 26. Has been. In addition, 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 are set. A first seal member 27 that seals between the negative pressure path to the chamber 21, a second seal member 28 that seals between the negative pressure path to the two-wheel drive-side negative pressure chamber 20 and the outside, and four wheels A third seal member 29 is provided for sealing between the negative pressure path to the drive side negative pressure chamber 21 and the outside.

  The outer gear 18 has inner teeth that engage with the outer teeth of the slide gear 19 on the inner periphery thereof, and is splined to the inner periphery of the hub housing 17 at the outer periphery. The slide gear 19 is splined to the outer periphery of the portion of the inner peripheral portion of the shaft end portion 11a of the front axle 11 protruding from the spindle 23.

  The diaphragm 22 is sandwiched between the outer reinforcing plate 30 and the inner reinforcing plate 31 at the center and is sandwiched between the cylindrical support member 32 and the diaphragm cover 33 at the 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 that passes through the center of the diaphragm 22. Further, the inner reinforcing plate 31 is attached to a portion on the outer side in the axial direction from the teeth of the slide gear 19 so as not to be slidable and relatively rotatable. The outer periphery of the diaphragm cover 33 is fixed to the outer periphery of the support member 32 in the axial direction, and the support member 32 is splined to the inner periphery of the hub housing 17 at the outer periphery in the axial direction.

  A fourth seal member that seals 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 is provided. A coil spring 36 for urging the outer reinforcing plate 30 toward the slide gear 19 is incorporated between the diaphragm cover 33 and the outer reinforcing plate 30.

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

  Then, the outer peripheral portion of a substantially annular wave spring 40 (see FIG. 4) is fitted and fixed in an annular groove provided in the inner periphery of the hub housing 17, and the flange portion 38 a of the operation piece 38 is axially fixed by the wave spring 40. The O-ring 39 is compressed by pressing outward. Thereby, even if the hub housing 17 is provided with the mounting hole 37, sufficient airtightness can be ensured. The O-ring 39 also serves to prevent the rotation of the operation piece 38 due to vibration or the like during traveling by giving an appropriate rotation resistance to the operation piece 38.

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

  The sleeve 41 has an annular magnet 42 attached to a stepped surface facing the outer reinforcing plate 30 of the diaphragm 22. 4 and FIG. 5, two protrusions 41a extending in the axial direction are provided on the outer peripheral surface of the large diameter portion of the sleeve 41. These protrusions 41a are the inner cylinders of the diaphragm cover 33. The sleeve 41 is supported so as to be slidable and non-rotatable relative to the operation piece 38 by being slidably fitted into an axial groove 33b provided on the inner peripheral surface of the portion 33a. Two engagement grooves 41 b extending obliquely with respect to the axial direction are provided in the large-diameter portion of the sleeve 41, and the engagement grooves 41 b of the sleeve 41 are formed on the outer peripheral surface of the other end portion of the operation piece 38. A pin 43 to be inserted is provided. Thus, when the operation piece 38 is rotated, the sleeve 41 is guided by the diaphragm cover 33 and moved in the axial direction by the engagement between 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 41b of the sleeve 41 is subjected to a surface treatment for reducing frictional resistance. The surface treatment for reducing the frictional resistance may be applied to both the engagement 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 freewheel hub mechanism 14 will be described. Normally, when a four-wheel drive vehicle is driven in a two-wheel drive state, the diaphragm 22 is elastically deformed by automatically depressurizing the two-wheel drive side negative pressure chamber 20 via one negative pressure port 25, The slide gear 19 connected to the diaphragm 22 in the axial direction 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 shown in FIG. 3). When traveling in a four-wheel drive state, the four-wheel drive side negative pressure chamber 21 is automatically depressurized via the other negative pressure port 25 to elastically deform the diaphragm 22, thereby causing the slide gear 19 to move to the outer gear. 18 is moved to a position where it meshes with the front wheel 13 to connect the front wheel 13 and the front axle 11 (state shown in FIG. 6).

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

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

  That is, first, as shown in FIG. 3, in the state where the front wheel 13 and the front axle 11 are disconnected (two-wheel drive state), the automatic switching operation using the negative pressure is not possible. 38, the sleeve 41 engaged with the operation piece 38 is moved in the axial direction (advanced), and the diaphragm 22 is pushed and moved by the sleeve 41, and the diaphragm 22 is moved in the axial direction. The front wheel 13 and the front axle 11 can be connected by moving the slide gear 19 connected in step (b) to a position where the slide gear 19 meshes with the outer gear 18 (state shown in FIG. 7).

  In addition, as shown in FIG. 6, when the automatic switching operation cannot be performed when the front wheel 13 and the front axle 11 are connected (four-wheel drive state), the operation piece 38 is once moved in a predetermined direction. By rotating, the sleeve 41 is advanced until it abuts against the outer reinforcing plate 30 of the diaphragm 22, and the magnet 42 attached to the sleeve 41 is brought into a state of adsorbing the outer reinforcing plate 30 (the 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 in FIG. 3). The front wheel 13 and the front axle 11 can be cut.

  As described above, the freewheel 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 to move the outer gear attached to the front wheel 13. 18 can be engaged with or released from the engagement, so that the front wheel 13 and the front axle 11 can be switched between connection and disconnection even when the slide gear 19 cannot be moved automatically.

  Therefore, in a four-wheel drive vehicle incorporating the freewheel hub mechanism 14, the switching operation is performed even in an emergency where the switching operation between the front wheel 13 and the front axle 11 cannot be automatically performed. By performing manually according to the above, it is possible to operate in the same manner as normal time except that it takes a little time for manual switching.

  In the embodiment described above, the wave spring that presses the flange portion 38a of the operation piece 38 outward in the axial direction in order to compress the O-ring 39 disposed between the hub housing 17 and the operation piece 38 to ensure airtightness. As shown in FIG. 8, a retaining ring 44 is fitted and fixed in an annular groove on the inner periphery of the hub housing 17, and is arranged between the retaining ring 44 and the flange portion 38 a of the operating piece 38. The flange portion 38a of the operation piece 38 may be pressed outward in the axial direction by the disc spring 45.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

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

11 Front axle (driven axle)
11a Shaft end 13 Front wheel (driven wheel)
14 Free wheel hub mechanism 15 Wheel hub 17 Hub housing 18 Outer gear 19 Slide gear 20 Two-wheel drive side negative pressure chamber 21 Four-wheel drive side negative pressure chamber 22 Diaphragm 36 Coil spring 37 Mounting hole 37a Step surface 38 Operation piece 38a Flange portion 39 O-ring (elastic seal member)
40 Wave Spring 41 Sleeve 41b Engaging Groove 42 Magnet 43 Pin 44 Retaining Ring 45 Belleville Spring

Claims (5)

A hub housing, which is disposed on a radially outer side of a shaft end portion of a driven-side axle of a four-wheel drive vehicle so as to be rotatable relative to the driven-side axle, and is fixed to the wheel hub. An outer gear that rotates integrally with the wheel hub and the hub housing, a slide gear that is slidably and relatively non-rotatably fitted to the shaft end of the driven-side axle, and that can mesh with the outer gear, and the slide A non-slidable and relatively rotatable connection to the gear, and a diaphragm that partitions the interior of the hub housing into a two-wheel drive side negative pressure chamber and a four-wheel drive side negative pressure chamber;
When the four-wheel drive vehicle is driven in a 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. To move, to separate the driven wheel and the driven axle,
When driving the four-wheel drive vehicle in a four-wheel drive state, the four-wheel drive side negative pressure chamber is depressurized and the diaphragm is elastically deformed to move the slide gear to a position where it meshes with the outer gear. In the freewheel hub mechanism that connects the driven wheel and the driven axle,
A freewheel hub mechanism comprising means for manually moving the slide gear between a meshing position with the outer gear and a position where the meshing is released. The means for manually moving the slide gear is configured such that one end portion of a cylindrical operation piece facing the shaft end portion of the driven-side axle in the axial direction is rotatably fitted in a mounting hole provided in the hub housing, A sleeve that is slidably fitted to the outer periphery of the other end of the operation piece is supported so as to be slidable relative to the operation piece and not rotatable relative to the operation piece, and an engagement groove extending obliquely with respect to the axial direction is provided on the sleeve. The operation piece is provided with a pin to be inserted into the engagement groove of the sleeve,
When the operation piece is rotated, the sleeve is moved integrally with the slide gear in the axial direction by the engagement between the pin of the operation piece and the engagement groove of the sleeve. Item 4. The freewheel hub mechanism according to item 1.   A flange portion is provided on one end side of the operation piece, and a step surface facing the flange portion of the operation piece in the axial direction is provided in the mounting hole of the hub housing, and between the step surface and the flange portion of the operation piece. 3. The elastic seal member is compressed in the axial direction by pressing a flange portion of the operation piece with a wave spring fixed to an inner periphery of the hub housing. The freewheel hub mechanism described in 1.   A flange portion is provided on one end side of the operation piece, and a step surface facing the flange portion of the operation piece in the axial direction is provided in the mounting hole of the hub housing, and between the step surface and the flange portion of the operation piece. An elastic seal member is disposed on the flange portion of the operation piece and a disc spring disposed between a retaining ring fixed to the inner periphery of the hub housing, and the flange portion of the operation piece is pressed in the axial direction, The freewheel hub mechanism according to claim 2, wherein the elastic seal member is compressed.   5. The freewheel hub mechanism according to claim 2, 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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