WO2016175143A1

WO2016175143A1 - Free-wheel hub

Info

Publication number: WO2016175143A1
Application number: PCT/JP2016/062725
Authority: WO
Inventors: 佐藤　光司; 尚弘岡田; 齋藤　隆英
Original assignee: Ntn株式会社
Priority date: 2015-04-27
Filing date: 2016-04-22
Publication date: 2016-11-03
Also published as: JP2016203895A; JP6494398B2

Abstract

A free-wheel hub is configured so that: a four-wheel drive state is maintained by an elastic member (29) for pressing an outer reinforcement plate (15) for a diaphragm (13); a slide gear (11) is disengaged from an outer gear (8) by the deformation of the diaphragm (13) toward a two-wheel drive-side negative pressure chamber (21); and a two-wheel drive state is maintained by the action of a magnet (30) which attracts the outer reinforcement plate (15). The weight of a movable part, such as the slide gear (11), which moves with the diaphragm (13) is reduced by material removal to reduce a load generated by vibration (G), thereby increasing force for maintaining the two-wheel drive state.

Description

Freewheel hub

This invention relates to a freewheel hub for a four-wheel drive vehicle.

The FR-based four-wheel drive vehicle has a transfer that distributes the power from the engine and the transmission to the front propeller shaft and the rear propeller shaft, and the two-wheel drive (2WD) and four-wheel drive (4WD) are transferred by the transfer. Switching is performed.

Here, when the driven side wheel and the driven side axle are in a coupled state during traveling by two-wheel drive, the driven side axle is rotated from the driven side wheel, so that the traveling resistance increases and energy is wasted. Will be consumed.

In order to eliminate such inconvenience, in the four-wheel drive vehicle described in Patent Document 1 below, a free wheel hub is provided between the driven wheel and the driven axle, and the transfer is switched to two-wheel drive. The driven wheel is separated from the driven axle, and the driven wheel is set in a free state so as to reduce useless running resistance. On the other hand, when the transfer is switched to four-wheel drive, the driven wheel and the driven axle are locked, and the power from the engine is transmitted to the driven wheel.

In order to switch between two-wheel drive and four-wheel drive, in the free wheel hub described in Patent Document 1, the wheel hub of the driven wheel is provided rotatably on the same axis as the driven axle, and the outside of the wheel hub. A two-wheel drive side negative pressure chamber and a four-wheel drive side negative pressure chamber are formed by incorporating a diaphragm into a hub housing connected to the side end face. Deform toward the wheel drive side negative pressure chamber, slide the slide gear connected to the diaphragm on the driven side axle to release the mesh with the outer gear built in the hub housing, and move it to the driven side axle On the other hand, the wheel hub is in a free state.

Further, the diaphragm is deformed toward the four-wheel drive-side negative pressure chamber by depressurization of the four-wheel drive-side negative pressure chamber, and a slide gear that moves toward the outer gear side is engaged with the outer gear so that the wheel hub is driven. Locked to the axle.

Here, in order to maintain the two-wheel drive state (free state) or the four-wheel drive state (lock state), the pressure reduction of the two-wheel drive side negative pressure chamber or the four-wheel drive side negative pressure chamber is maintained for a long time. If so, a large suction force is always applied to the sealing member that seals each of the negative pressure chambers and the sealing seal member of the suction path that communicates with each negative pressure chamber, and the function of the sealing member is reduced, Durability will be reduced.

In order to eliminate such inconvenience, in the above free wheel hub, a magnet is attached to the inner surface of the diaphragm cover that holds the outer periphery of the diaphragm, and the magnet adsorbs an outer reinforcing plate provided outside the diaphragm. The two-wheel drive state is maintained.

Also, a spring is incorporated between the diaphragm cover and the outer reinforcing plate, and the four-wheel drive state is maintained by the action of the spring pressing the diaphragm toward the four-wheel drive side negative pressure chamber. At this time, since the two-wheel drive state cannot be maintained if the magnetic force by the magnet is smaller than the elastic force of the spring, the magnetic force by the magnet is set to a value higher than the elastic force of the spring.

Specifically, when the magnetic force of the magnet is Fm, the elastic force of the spring is Fs, the acting force due to the switchable negative pressure is Fao, the weight of the movable part moving together with the diaphragm is M, and the vibration G is H, the following

formula

1 , 2 is satisfied.
Switchable to four-wheel drive; Fs + Fao> Fm + M × H Equation 1
Maintains two-wheel drive state; Fm> Fs + M × H Equation 2

JP-A-10-278621

By the way, as described above, in the freewheel hub that maintains the two-wheel drive state by magnetically attracting the outer reinforcing plate as described above, the magnetic force of the magnet is required to reliably maintain the two-wheel drive state from the above conditions. Although there is a means for increasing Fm or decreasing the elastic force Fs of the spring, it is necessary to increase the negative pressure Fao for switching to the four-wheel drive state.

In the freewheel hub, since the negative pressure of the intake pipe of the vehicle is used, it is difficult to increase the negative pressure. The two-wheel drive state is achieved by changing the magnetic force Fm of the magnet or the elastic force Fs of the spring. The holding power cannot be improved.

Here, when the adsorption of the outer reinforcing plate is released due to a large vibration load in a traveling state with two-wheel drive, the slide gear may mesh with the outer gear and switch to the four-wheel drive state. When only one wheel is switched, normal driving is possible, but noise is generated, and when both wheels are switched to the four-wheel drive state, a tight brake phenomenon occurs at the corner, which is related to the driver's intention. Therefore, the braking force acts on the vehicle and decelerates to give the driver anxiety. Therefore, the improvement of the holding force in the two-wheel drive state is a very important issue.

An object of the present invention is to improve the holding force in a two-wheel drive state in the above-described free wheel hub that holds a two-wheel drive state with a magnet and holds a four-wheel drive state with an elastic member.

In order to solve the above-described problems, in the present invention, the outside side of a wheel hub that is rotatably supported by inserting a driven-side axle inside a cylindrical spindle and is rotatably supported around the spindle. A hub housing that covers the shaft end of the driven-side axle is provided at the end, and an outer gear is provided in the hub housing so as to be integrally rotatable, and can be meshed with the outer gear on the shaft end of the driven-side axle. Slidably supports a sliding gear, and a reinforcing plate that reinforces the inner periphery of the diaphragm that divides the inside of the hub housing into a two-wheel drive negative pressure chamber and a four-wheel drive negative pressure chamber is rotatable to the slide gear. And the two-wheel drive is made by moving the slide gear to a position where the engagement with the outer gear is released by elastic deformation of the diaphragm due to the pressure reduction of the two-wheel drive side negative pressure chamber. A magnet disposed opposite to the reinforcing plate in the axial direction maintains the two-wheel drive state by the action of magnetically attracting the reinforcing plate, and the slide gear is caused by elastic deformation of the diaphragm due to the pressure reduction of the four-wheel drive side negative pressure chamber. Of a plurality of movable parts that move with the diaphragm in a free wheel hub that moves to a position that meshes with the outer gear to achieve four-wheel drive, and that retains the four-wheel drive state by the elastic force of an elastic member that presses the reinforcing plate. A configuration in which at least one part is subjected to a weight reduction process by thinning is employed.

As described above, the load generated by the vibration G can be reduced by reducing the weight by removing at least one of the plurality of movable parts moved by the deformation of the diaphragm. It is possible to improve the holding force in the driving state.

Here, the parts to be lightened by lightening are the slide gear, the outer reinforcing plate that is provided on the outer surface side of the diaphragm and attracted and held by the magnet, and the inner surface side of the diaphragm that is rotatable on the slide gear. Any one of an inner reinforcing plate connected to each other and a rivet that connects the outer reinforcing plate and the central portion of the inner reinforcing plate to each other may be used. When the slide gear is a target component for weight reduction processing, a large-diameter concave portion is formed at the outside side end portion of the slide gear to reduce the thickness. In this case, since a retaining ring groove for mounting the retaining ring for the coupling to the inner reinforcing plate is formed on the outer diameter surface of the slide gear, the thickness between the inner diameter surface of the recess and the groove bottom of the retaining ring groove is set. As the depth of the heat-treated hardened layer applied to the surface layer of the slide gear exceeds the depth, a decrease in strength is suppressed.

In addition, when the outer reinforcing plate and the inner reinforcing plate are to be subjected to weight reduction processing, the holes are drilled. Furthermore, when a rivet is a target part for weight reduction processing, a recess is formed in the rivet to remove the meat.

In the present invention, as described above, a plurality of movable parts including the slide gear moved by deformation of the diaphragm, the inner and outer reinforcing plates that reinforce the central portion of the diaphragm, and the rivets that connect the pair of reinforcing plates. By reducing the weight by removing at least one of the components, the load generated by the vibration G is reduced, and the holding force in the two-wheel drive state can be improved.

A longitudinal sectional view showing an embodiment of a freewheel hub according to the present invention Sectional drawing which expands and shows a part of FIG. Sectional view showing the four-wheel drive state of the freewheel hub Perspective view showing outer reinforcing plate Perspective view showing the inner reinforcing plate The graph which shows the measurement result of vibration resistance G of the product of the present invention when the slide gear is thinned and reduced in weight and the comparative product which is not thinned

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, a front axle 1 as a driven axle and a wheel hub 2 of a front wheel as a driven wheel provided outside thereof are arranged coaxially.

A cylindrical spindle 3 is incorporated between the front axle 1 and the wheel hub 2. The spindle 3 has a flange 3a at an end portion on the inside side (right side in FIG. 1 and means the vehicle body side), and the flange 3a is fixed. A bush 4 is incorporated in the inside end portion of the spindle 3, and the front axle 1 is rotatably supported by the bush 4.

Further, a rolling bearing 5 composed of a double row outward angular ball bearing is incorporated in the outer periphery of the spindle 3, and the wheel hub 2 is rotatably supported by the rolling bearing 5.

A hub housing 7 is connected to an end surface of the wheel hub 2 on the outside side (the left side in FIG. 1 and means the wheel side) by tightening a bolt 6 screwed into the wheel hub 2. An outer gear 8 and a sleeve 9 are incorporated in the hub housing 7 on the outer side in the axial direction.

The outer gear 8 has a ring shape, and spline teeth 8a as tooth portions are formed on the inner periphery thereof. Each of the outer gear 8 and the sleeve 9 is fixed to the inner diameter surface of the hub housing 7 by fitting with a spline and rotates integrally with the hub housing 7. The outer gear 8 and the sleeve 9 are opposed to each other in the axial direction. The gap is sealed by incorporating a seal member 10.

A slide gear 11 is fitted to the shaft end located inside the hub housing 7 of the front axle 1. The slide gear 11 is prevented from rotating on the front axle 1 by the fitting of the serration 12 and is supported so as to be movable in the axial direction. Spline teeth 11 a that can mesh with the spline teeth 8 a of the outer gear 8 are formed on the outer diameter surface thereof. Is provided.

It should be noted that the slide gear 11 may be prevented from rotating around the front axle 1 and supported so as to be movable in the axial direction as a spline fitting instead of the serration 12 fitting.

A diaphragm 13 is incorporated inside the hub housing 7 on the outer side in the axial direction of the sleeve 9. The outer peripheral portion of the diaphragm 13 is sandwiched from both sides by an outer side end surface of the sleeve 9 and a diaphragm cover 14 having a cylindrical portion 14a on the outer periphery of the sleeve 9 that is press-fitted to the outer periphery of the outer side end portion of the sleeve 9. Yes.

The central portion of the diaphragm 13 is sandwiched between the outer reinforcing plate 15 and the inner reinforcing plate 16 from both sides, and the outer reinforcing plate 15 and the inner reinforcing plate 16 are coupled and integrated by caulking a rivet 17 inserted through the center hole. ing.

The outer reinforcing plate 15 and the inner reinforcing plate 16 are made of a press-formed product of a magnetic metal plate, and a tapered tube portion 15a is formed on the outer peripheral portion of the outer reinforcing plate 15 as shown in FIG. As shown in FIG. 2, each of the plurality of projecting pieces 15b formed at the opening end of 15a is slidably inserted into each of the same number of non-rotating holes 14b as the projecting pieces 15b formed in the diaphragm cover 14. The outer reinforcing plate 15 is prevented from rotating with respect to the diaphragm cover 14 by the engagement of the protruding piece 15b with the rotation preventing hole 14b.

On the other hand, a cylindrical portion 16a is provided on the outer peripheral portion of the inner reinforcing plate 16, as shown in FIGS. 2 and 5, and the opening end of the cylindrical portion 16a is bent inward to form an inner cylindrical portion 16b. The inner cylinder portion 16b is fitted into a cylindrical outer diameter surface 11b formed on the outer periphery of the outer side end portion of the slide gear 11, and is axially rotated in a state of being rotatable relative to the slide gear 11. It is connected.

When the inner reinforcing plate 16 and the slide gear 11 are connected in the axial direction, a retaining ring groove 19 is formed at the end of the cylindrical outer diameter surface 11 b of the slide gear 11, and an inner peripheral portion is formed in the retaining ring groove 19. The outer peripheral portion of the fitted retaining ring 20 is disposed opposite to the end portion of the inner cylinder portion 16b in the axial direction.

By incorporating the diaphragm 13, a two-wheel drive side negative pressure chamber 21 is formed inside the hub housing 7 in the axial direction outside of the diaphragm 13, and a four-wheel drive side negative pressure chamber 22 is formed in the axial direction inside of the diaphragm 13. Has been.

As shown in FIG. 1, a ring member 23 is fitted to the outside end portion of the spindle 3, and a cylindrical portion 23 a provided at the outside side end portion of the ring member 23 and an open end portion of the hub housing 7. Are opposed to each other in the radial direction, and the gap between the opposed portions is hermetically sealed by incorporating a seal member 24.

The flange 3 a at the inside end of the spindle 3 and the facing portion of the wheel hub 2 are sealed by incorporating a pair of seal members 25. Further, the radial facing portions of the front axle 1 and the flange 3 a are also sealed by incorporating the seal member 26.

The flange 3a of the spindle 3, the first port _{P 1} and the second port _{P 2} is provided. The first port P ₁ communicates with the two-wheel drive-side negative pressure chamber 21 via a first suction path 27 formed between the inner periphery of the wheel hub 2 and the outer periphery of the spindle 3 and on the inner diameter surface of the hub housing 7. two-wheel drive-side negative pressure chamber 21 is depressurized by sucking the first port P _1.

Meanwhile, the second port P ₂ communicates via the second suction passage 28 provided between the inner periphery of the outer peripheral and the spindle 3 of the front axle 1, the four-wheel drive side by sucking the second port P ₂ The negative pressure chamber 22 is depressurized.

As shown in FIG. 2, an elastic member 29 made of a spring and a magnet 30 are incorporated inside the diaphragm cover 14. The elastic member 29 urges the slide gear 11 toward the outer gear 8 through the diaphragm 13 and holds the slide gear 11 in a state of meshing with the outer gear 8.

On the other hand, when the magnet 30 is fixed to the inner surface of the end plate of the diaphragm cover 14 and the diaphragm 13 is deformed toward the negative pressure chamber 21 on the two-wheel drive side, the slide gear 11 is disengaged from the outer gear 8. The outer reinforcing plate 15 is magnetically attracted to hold the slide gear 11 in the disengaged state.

Each of the slide gear 11, the outer reinforcing plate 15, the inner reinforcing plate 16 and the rivet 17 forms a movable part that moves together with the diaphragm 13. Each of the plurality of movable parts is reduced in weight by being thinned.

At the time of weight reduction processing, the slide gear 11 is formed with a large-diameter recess 31 on the inner diameter of the outside end, and is thinned, and between the inner diameter surface of the large-diameter recess 31 and the groove bottom of the retaining ring groove 19. The thickness is set to be equal to or greater than the depth of the heat-treated hardened layer applied to the surface layer of the slide gear 11 in order to avoid a decrease in strength.

In the lightening process for the outer reinforcing plate 15, as shown in FIGS. 2 and 4, a plurality of holes 32 are formed in the tapered cylindrical portion 15 a formed in the outer reinforcing plate 15 at intervals in the circumferential direction. In the lightening process for the inner reinforcing plate 16, as shown in FIGS. 2 and 5, a plurality of holes 33 are formed in the inner reinforcing plate 16 at intervals in the circumferential direction. Further, in the process of reducing the weight of the rivet 17, as shown in FIGS. 1 and 2, a recess 34 is provided at the center of the rivet 17.

In the embodiment shown in FIGS. 1 and 2, each of the slide gear 11, the outer reinforcing plate 15, the inner reinforcing plate 16, and the rivet 17 is subjected to weight reduction processing. You may make it perform the weight reduction process to one.

The freewheel hub shown in the embodiment has the above-described structure. FIGS. 1 and 2 show a traveling state by two-wheel drive, and as shown in FIG. 2, the diaphragm 13 is placed in the two-wheel drive side negative pressure chamber 21. The slide gear 11 is in a state of releasing meshing with the outer gear 8.

In the running state by the two-wheel drive shown in FIGS. 1 and 2, when applying a suction force to the second port P _2, four-wheel drive-side negative pressure chamber 22 is depressurized, the diaphragm 13 is 4-wheel drive-side negative pressure chamber 22 Elastically deforms toward

Due to the elastic deformation of the diaphragm 13, the slide gear 11 moves toward the outer gear 8 and meshes with the outer gear 8 as shown in FIG. 3, and the wheel hub 2 is in a locked state coupled to the front axle 1. The rotation is transmitted from the front axle 1 to the wheel hub 2.

At this time, the slide gear 11 is held in mesh with the outer gear 8 by the elastic force of the elastic member 29. Therefore, even if it releases the suction for the second port P ₂ to the atmospheric pressure, locking hubs it is maintained in the running state of the four-wheel drive.

Upon switching from the running state of the four-wheel drive shown in FIG. 3 to the running state of the two-wheel drive, a suction force is applied to depressurize the two-wheel drive-side negative pressure chamber 21 to the first port P _1. Due to the reduced pressure, the diaphragm 13 is elastically deformed toward the two-wheel drive-side negative pressure chamber 21, and the slide gear 11 connected to the diaphragm 13 moves away from the outer gear 8, and as shown in FIG. It is disposed at the two-wheel drive switching position where the meshing with the outer gear 8 is released, the wheel hub 2 is disconnected from the front axle 1 and is in a free state, and the rotation transmission from the wheel hub 2 to the front axle 1 is cut off. become.

In the state of switching to the two-wheel drive, the magnet 30 provided in the diaphragm cover 14 attracts the outer reinforcing plate 15. Even if the atmospheric pressure by releasing the suction for the first port P ₁ by its adsorption, locking hubs are maintained in the two-wheel drive state.

In maintaining the two-wheel drive state, here, the above-described mathematical formula, Fm> Fs + M × H, is set. However, when the weight M of the movable part becomes heavy, the outer reinforcing plate 15 by the magnet 30 is caused by a large vibration load. There is a possibility that the suction is released and the four-wheel drive is switched.

However, in the embodiment, the movable part weight M is reduced by thinning the slide gear 11, the outer reinforcing plate 15, the inner reinforcing plate 16, and the rivet 17 as movable parts that move together with the diaphragm 13. Therefore, the load generated by the vibration G is reduced, the holding force in the two-wheel drive state is improved, and the freewheel hub is reliably maintained in the two-wheel drive state and switched to the four-wheel drive state. There is no inconvenience.

Here, when the vibration resistance G was measured using the product of the present invention in which the slide gear was lightened to reduce the weight and the slide gear that was not thinned as a comparative product, the measurement results shown in the graph of FIG. 6 were obtained. As is apparent from the measurement results, the product of the present invention has greatly improved vibration resistance G compared to the comparative product, and the two-wheel drive retention can be improved.

Note that the graph of FIG. 6 shows the measurement results when only the slide gear is thinned, and the outer reinforcing plate 15, the inner reinforcing plate 16 and the rivet 17 are thinned, whereby the vibration resistance G Is further improved.

1 Front axle (driven axle)
2 Wheel hub 3 Spindle 7 Hub housing 8 Outer gear 11 Slide gear 13 Diaphragm 15 Outer reinforcement plate 16 Inner reinforcement plate 17 Rivet 21 Two-wheel drive side negative pressure chamber 22 Four-wheel drive side negative pressure chamber 29 Elastic member 30 Magnet 31 Large diameter recess 32 hole 33 hole 34 depression

Claims

A driven axle is inserted into the cylindrical spindle and supported rotatably, and the outside end of the wheel hub that is rotatably supported around the spindle covers the shaft end of the driven axle. A hub housing is provided, and an outer gear is provided in the hub housing so as to be integrally rotatable. A slide gear that can mesh with the outer gear is slidably supported on the shaft end portion of the driven-side axle. A reinforcing plate that reinforces the inner periphery of a diaphragm that divides the interior of the diaphragm into a two-wheel drive side negative pressure chamber and a four-wheel drive side negative pressure chamber is rotatably connected to the slide gear, The slide gear is moved to a position where the engagement with the outer gear is released by the elastic deformation of the diaphragm due to the reduced pressure, and the two-wheel drive is performed. The two-wheel drive state is maintained by the action of magnetically attracting the reinforcing plate, and the four-wheel drive is performed by moving the slide gear to a position where it meshes with the outer gear by the elastic deformation of the diaphragm due to the pressure reduction of the four-wheel drive side negative pressure chamber In a freewheel hub that maintains a four-wheel drive state by the elastic force of an elastic member that presses the reinforcing plate,
A freewheel hub characterized in that at least one of a plurality of movable parts moving together with the diaphragm is subjected to a weight reduction process by lightening.
The reinforcing plate is provided on the outer surface side of the diaphragm and is attracted and held by the magnet, and the inner reinforcing plate is provided on the inner surface side of the diaphragm and is rotatably connected to the slide gear. The freewheel hub according to claim 1, comprising:
The free wheel hub according to claim 1 or 2, wherein the slide gear is a target part for weight reduction processing by lightening.
The weight reduction process of the slide gear is such that the thickness between the inner diameter surface of the concave portion and the bottom of the retaining ring groove of the connecting retaining ring with respect to the inner reinforcing plate is formed by forming a large-diameter concave portion with respect to the outer side end portion. The freewheel hub according to claim 3, wherein the freewheel hub has a depth equal to or greater than a depth of the heat-treated hardened layer applied to the surface layer of the slide gear.
The free wheel hub according to claim 2, wherein the outer reinforcing plate is a target part for weight reduction processing by thinning, and the thinning is performed by drilling a hole.
The free wheel hub according to claim 2, wherein the inner reinforcing plate is a target part for weight reduction processing by thinning, and the thinning is performed by drilling a hole.
The free wheel hub according to claim 2, wherein the rivet connecting the outer reinforcing plate and the central portion of the inner reinforcing plate is a target part for weight reduction processing by thinning, and the thinning is performed by forming a recess.