JP2011131693A - Free wheel hub - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance reliability of the maintenance function of a two-wheel driving state, in a free wheel hub for maintaining the two-wheel driving state by magnetic attraction force by a permanent magnet. <P>SOLUTION: A cap-shaped connecting member 14 for connecting a diaphragm 11 and a slide gear 9 is butted against one side surface of the diaphragm 11 for partitioning the inside of a hub housing 6 into a two-wheel driving side negative pressure chamber 40 and a four-wheel driving side negative pressure chamber 41, and a spring retainer 15 butted against its connecting member 14 and the other side surface of the diaphragm 11 is joined by a rivet 16. The permanent magnet 20 is fixed to an inner surface of the diaphragm 11, and the slide gear 9 is maintained in the two-wheel driving state of meshing with and releasing from an outer gear 7 fixed inside the housing 6 by the action of magnetically attracting the spring retainer 15 by its permanent magnet 20. A guide cylinder 31 is formed in a diaphragm cover 13 for holding an outer peripheral part of the diaphragm 11, and a cylindrical head part 16a of the rivet 16 is slidably guided by its guide cylinder 31, and the spring retainer 15 is prevented from inclining by vibration, and the two-wheel driving state is maintained. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

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

  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, a free wheel hub is provided between the driven wheel and the driven axle, and the transfer is switched to the two-wheel drive. The driven wheel is disconnected from the driven axle and the driven wheel is set free to reduce wasteful running resistance. On the other hand, when the transfer is switched to four-wheel drive, the driven wheel and the driven axle are locked. Thus, 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. 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. It is deformed toward the wheel drive side negative pressure chamber, the slide gear connected to the diaphragm is slid on the driven side axle, the meshing of the slide gear and the outer gear fixed inside the hub housing is released, and the driven The wheel hub is free with respect to the side axle.

  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 the wheel hub is moved to the driven side axle by meshing the slide gear and the outer gear moving toward the outer gear side. On the other hand, it is locked.

  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. In this case, a large suction force is always applied to the seal member that seals each of the negative pressure chambers and the seal member that seals the negative pressure path communicating with each of the negative pressure chambers, thereby reducing the function of the seal member. , Will reduce durability.

  In order to eliminate such inconvenience, in the above freewheel hub, a permanent magnet is attached to the inner surface of the diaphragm cover that holds the outer periphery of the diaphragm, and a spring retainer that is fixed to one side of the diaphragm is magnetically attached to the permanent magnet. The two-wheel drive state is maintained by the sucking action.

  Also, a spring is incorporated between the diaphragm cover and the spring retainer, and the four-wheel drive state is maintained by the action of the spring pressing the diaphragm. At this time, if the magnetic attractive force by the permanent magnet is smaller than the elastic force of the spring, the two-wheel drive state cannot be maintained, so the magnetic attractive force by the permanent magnet is set to a value higher than the pressing force of the spring.

Japanese Patent Laid-Open No. 10-278621

  By the way, as described above, in the free wheel hub that maintains the two-wheel drive state by the magnetic attraction force by the permanent magnet and maintains the four-wheel drive state by the pressing of the spring, it vibrates in the traveling state of the vehicle by the two-wheel drive. If the spring retainer tilts due to, etc., the magnetic attraction force decreases rapidly, and it is possible to switch to the four-wheel drive state by the elastic force of the spring even though the four-wheel drive side negative pressure chamber is not decompressed. There is a problem that the reliability of the maintenance function is low.

  An object of the present invention is to improve the reliability of a two-wheel drive state maintaining function in a freewheel hub configured to maintain a two-wheel drive state by a magnetic attractive force by a permanent magnet.

  In order to solve the above problems, in the present invention, a wheel hub of a driven wheel is provided rotatably on the same axis as the driven axle, and the hub hub connected to the outer side end surface of the wheel hub is provided in the hub housing. An outer gear that rotates integrally with the hub housing is provided, a slide gear is slidably fitted to the end of the driven axle located inside the hub housing, and is prevented from rotating. A cap-shaped connecting member that connects the diaphragm and the slide gear is abutted against one side surface of the diaphragm that partitions the driving side negative pressure chamber and the four-wheel driving side negative pressure chamber, and the connecting member and the other side surface of the diaphragm A diaphragm in which a spring retainer abutted on the outer periphery of the hub housing is coupled to support the outer peripheral portion of the diaphragm, and the outer peripheral portion is attached to the inner diameter surface of the hub housing. A permanent magnet that magnetically attracts the spring retainer is fixed to the inner surface of the diaphragm cover, and a spring that urges the diaphragm in the direction in which the slide gear meshes with the outer gear is incorporated between the diaphragm and the spring retainer. Due to the elastic deformation of the diaphragm due to the decompression of the side negative pressure chamber, the slide gear is moved in the direction to release the engagement with the outer gear and switched to the two-wheel drive, and the permanent magnet magnetically attracts the spring retainer to the two-wheel drive. The switching state is maintained, the slide gear is moved to a position where it meshes with the outer gear by the elastic deformation of the diaphragm due to the pressure reduction in the negative pressure chamber on the four-wheel drive side, and switched to the four-wheel drive, and the spring biases the diaphragm toward the outer gear. By this function, the state of switching to four-wheel drive is maintained. In the wheel hub, the mutual of the diaphragm cover and the spring re antenna it is had adopted a configuration in which a guide means for guiding sliding the spring re container in the axial direction.

  In the free wheel hub having the above-described configuration, the diaphragm is elastically deformed into the two-wheel drive side negative pressure chamber by reducing the pressure on the two-wheel drive side negative pressure chamber, and the slide gear is moved in the direction to release the engagement with the outer gear. When switched to wheel drive, the permanent magnet magnetically attracts the spring retainer. For this reason, even if the decompression of the two-wheel drive side negative pressure chamber is released, the freewheel hub is maintained in the two-wheel drive state.

  At this time, since the spring retainer is slidably guided in the axial direction by the guide means provided on the diaphragm cover, the spring retainer does not tilt due to vibration or the like. For this reason, a stable magnetic attractive force can be applied to the spring retainer, and the freewheel hub can be reliably maintained in the two-wheel drive state.

  Here, as a guide means for sliding and guiding the spring retainer in the axial direction, a guide tube provided at the center of the diaphragm cover, and a spring retainer which is slidable within the guide tube when switching to two-wheel drive. What consists of a circular protrusion part fitted by can be employ | adopted.

  In this case, the diaphragm is elastically directed toward the two-wheel drive-side negative pressure chamber by forming a chamfer on at least one of the intersecting portion of the front end surface and the outer diameter surface of the guide tube and the outer peripheral portion of the end surface of the circular protrusion. At the time of switching to the two-wheel drive to be deformed, the circular protrusion can smoothly enter the guide cylinder, and the two-wheel drive state can be reliably switched.

  The circular protrusion in the guide means may be the head of a rivet that is inserted through the central part of the connecting member and the spring retainer to combine and integrate the two members, or centered on the axis of the spring retainer. It may be composed of a plurality of cut and raised pieces arranged on the same circle.

  When the rivet head is a circular protrusion, if the rivet is made of a non-magnetic material such as aluminum or stainless steel, magnetic flux leakage is prevented, and the magnetic attractive force between the permanent magnet and the spring retainer Can be increased.

  As described above, in the freewheel hub according to the present invention, the guide means for slidingly guiding the spring retainer in the axial direction is provided between the diaphragm cover and the spring retainer. Therefore, it is possible to prevent the spring retainer magnetically attracted by the permanent magnet from being tilted due to vibration or the like, and the free wheel hub can be reliably maintained in the two-wheel drive state.

Vertical front view showing an embodiment of a freewheel hub according to the present invention Sectional drawing which expands and shows the center part of the diaphragm shown in FIG. Sectional view showing the locked state of the wheel hub (I) is a sectional view showing another example of the guiding means, (II) is a partially cutaway side view of (I)

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a front axle 1 as a driven axle and a wheel hub 2 of a front wheel (driven wheel) provided on the outside thereof are arranged coaxially.

  A cylindrical spindle 3 is incorporated between the front axle 1 and the wheel hub 2, and the spindle 3 and the wheel hub 2 are relatively rotatably supported by a bearing 4.

  A hub housing 6 is coupled to the outer end surface of the wheel hub 2 by tightening bolts 5. The outer gear 7 incorporated in the hub housing 6 has an annular shape, and spline teeth 8 are formed on the inner surface thereof. The outer gear 7 is fixed to the inner diameter surface of the hub housing 6 and rotates integrally with the hub housing 6.

  A slide gear 9 is fitted to an end portion of the front axle 1 located inside the hub housing 6. The slide gear 9 is prevented from rotating around the front axle 1 by fitting of a spline or serration, and is movable in the axial direction. A spline tooth 10 that can mesh with the spline teeth 8 of the outer gear 7 is formed on the outer diameter surface thereof. Is provided.

  A diaphragm 11 is incorporated in the hub housing 6. The outer peripheral portion of the diaphragm 11 is sandwiched from both sides by a diaphragm cover 13 having a fixing ring 12 and a cylindrical portion 13a fitted to the small diameter cylindrical portion 12a of the fixing ring 12 on the outer periphery, and the fixing ring 12 is held in the hub housing 6. Are fixed to the hub housing 6.

  Further, the inner peripheral portion of the diaphragm 11 is sandwiched from both sides by a cap-shaped connecting member 14 and a spring retainer 15 made of a plate-shaped magnetic metal coupled and integrated with the connecting member 14. As shown in FIG. 2, the connecting member 14 and the spring retainer 15 are coupled and integrated by crimping the end of the rivet 16 inserted through the center.

  The open end of the cylindrical portion 17 formed on the outer periphery of the connecting member 14 is bent inward to form an inner cylindrical portion 17 a that overlaps the inner diameter surface of the cylindrical portion 17, and the inner cylindrical portion 17 a is a cylinder of the slide gear 9. The outer peripheral surface 9a is engaged with the slide gear 9 in the axial direction.

  When connecting the connecting member 14 and the slide gear 9 in the axial direction, here, a ring groove 18 is formed at the end of the cylindrical outer diameter surface 9a of the slide gear 9, and a retaining ring 19 is attached to the ring groove 18, The retaining ring 19 is engaged with the end portion of the inner cylindrical portion 17a.

  As shown in FIG. 2, a permanent magnet 20 is attached to the inner periphery of the inner surface of the diaphragm cover 13. The permanent magnet 20 may be annular, or may be a plurality of permanent magnet pieces arranged annularly. The permanent magnet 20 magnetically attracts the spring retainer 15 with the slide gear 9 disengaged from the outer gear 7 to hold the slide gear 9 in the disengaged state.

  Here, the material of the rivet 16 is arbitrary, but if the rivet 16 is formed of a magnetic material, the magnetic flux of the permanent magnet 20 leaks to the rivet 16 and the magnetic attractive force becomes weak. 16 is preferably formed of a nonmagnetic material such as aluminum or stainless steel.

  A spring 21 is incorporated between the facing surfaces of the diaphragm cover 13 and the spring retainer 15. The spring 21 urges the diaphragm 11 in the direction in which the slide gear 9 meshes with the outer gear 7, and the elastic force of the spring 21 is set to a value smaller than the magnetic attractive force of the permanent magnet 20.

  Between the diaphragm cover 13 and the spring retainer 15, there is provided guide means 30 that slides and guides the spring retainer 15 in the axial direction while the permanent magnet 20 magnetically attracts the spring retainer 15.

  As the guide means 30, here, as shown in FIG. 2, the head portion 16 a of the rivet 16 is circular, and the diaphragm cover 13 is provided with a guide cylinder 31 at the center, and the guide cylinder 31 allows the circular head 16 a to be formed. Is slidably guided.

  Here, in order to allow the head 16a of the rivet 16 to smoothly enter the guide tube 31, a chamfer 31c is formed at the intersection of the distal end surface and the outer diameter surface of the guide tube 31, while the head 16a of the rivet 16 is formed. Although the chamfer 16c is provided also on the outer peripheral portion of the end face, the chamfer may be formed only on one of the guide tube 31 and the head 16a.

  As shown in FIG. 1, by incorporating the diaphragm 11 into the inside of the hub housing 6, a two-wheel drive side negative pressure chamber 40 and a four-wheel drive side negative pressure chamber 41 are formed inside the hub housing 6. By depressurizing the wheel drive side negative pressure chamber 40, the diaphragm 11 is deformed toward the two wheel drive side negative pressure chamber 40, and the slide gear 9 moves in a direction away from the outer gear 7. The meshing is released.

  Further, by depressurizing the four-wheel drive side negative pressure chamber 41, the diaphragm 11 is deformed toward the four-wheel drive side negative pressure chamber 41, and the slide gear 9 moves toward the outer gear 7 and meshes with the outer gear 7. It is supposed to be.

  Reference numeral 42 denotes a suction path that communicates with the two-wheel drive-side negative pressure chamber 40, and reference numeral 43 denotes a suction path that communicates with the four-wheel drive-side negative pressure chamber 41. Further, reference numeral 44 denotes a seal member that seals between the suction path 42 communicating with the two-wheel drive side negative pressure chamber 40 and the suction path 43 communicating with the four-wheel drive side negative pressure chamber 41.

  The freewheel hub shown in the embodiment has the above-described structure, and the four-wheel drive side negative pressure chamber 41 is decompressed when traveling by four-wheel drive. Due to the pressure reduction, the diaphragm 11 is deformed toward the four-wheel drive-side negative pressure chamber 41, the slide gear 9 moves toward the outer gear 7, and meshes with the outer gear 7, as shown in FIG. The locked state is coupled to the front axle 1, and the rotation is transmitted from the front axle 1 to the wheel hub 2.

  At this time, since the spring 21 urges the diaphragm 11 in the direction in which the slide gear 9 meshes with the outer gear 7, the freewheel hub is 4 even if the decompression to the four-wheel drive side negative pressure chamber 41 is released. The wheel drive state is maintained.

  On the other hand, when traveling by two-wheel drive, the two-wheel drive side negative pressure chamber 40 is decompressed. Due to the pressure reduction, the diaphragm 11 is deformed toward the two-wheel drive-side negative pressure chamber 40, and the slide gear 9 connected to the diaphragm 11 moves in a direction away from the outer gear 7, and as shown in FIG. 7 is released, the wheel hub 2 is disconnected from the front axle 1 and becomes free, and the rotation transmission from the wheel hub 2 to the front axle 1 is cut off.

  In the switching state to the two-wheel drive as described above, since the permanent magnet 20 magnetically attracts the spring retainer 15, the freewheel hub is in the two-wheel drive state even if the decompression to the two-wheel drive side negative pressure chamber 40 is released. Maintained.

  Further, in the two-wheel drive state of the freewheel hub, the head portion 16 a of the rivet 16 is slidably guided into the guide tube 31 formed on the diaphragm cover 13. The sliding guide prevents the spring retainer 15 from tilting due to vibration or the like, the magnetic attraction force applied from the permanent magnet 20 to the spring retainer 15 becomes stable, and the freewheel hub is driven by two wheels. It will be reliably maintained in a state.

  In the embodiment shown in FIG. 1, as the guide means 30, the head 16 a of the rivet 16 is a circular projecting portion, and the circular projecting portion is slidably guided by a guide tube 31 formed on the diaphragm cover 13. The circular protrusion is not limited to the head 16a of the rivet 16.

  For example, as shown in FIGS. 4 (I) and (II), a plurality of cut and raised pieces 32 are provided on the spring retainer 15 on the same circle centered on the axis of the spring retainer 15, and the plurality of cut and raised pieces are provided. The piece 32 may be slid and guided by the guide cylinder 31 as a circular protrusion.

  In this case, it is preferable that a chamfer 32 c is formed on the outer peripheral portion of each tip end surface of the plurality of cut and raised pieces 32 so as to smoothly enter the guide tube 31.

1 Front axle (driven axle)
2 Wheel hub 6 Hub housing 7 Outer gear 9 Slide gear 11 Diaphragm 12 Fixing ring 13 Diaphragm cover 14 Connecting member 15 Spring retainer 16 Rivet 16a Circular head (circular protrusion)
16c Chamfer 20 Permanent magnet 21 Spring 30 Guide means 31 Guide cylinder 31c Chamfer 32 Cut and raised piece (circular protrusion)
32c Chamfer 40 Two-wheel drive side negative pressure chamber 41 Four-wheel drive side negative pressure chamber

Claims (8)

A wheel hub of a driven wheel is coaxially provided with the driven axle, and an outer gear that rotates integrally with the hub housing is provided in a hub housing connected to an outer side end surface of the wheel hub. A slide gear is slidably fitted to an end of a driven axle located inside the housing and is prevented from rotating, and the inside of the hub housing has a two-wheel drive side negative pressure chamber and a four-wheel drive side negative pressure chamber. The diaphragm is partitioned into a cap-shaped connecting member that connects the diaphragm and the slide gear, and a spring retainer that is engaged with the other side of the diaphragm is connected to the diaphragm. The spring retainer is magnetically absorbed by the inner surface of the diaphragm cover that supports the outer peripheral portion of the hub housing and has the outer peripheral portion attached to the inner peripheral surface of the hub housing. And a spring that urges the diaphragm in the direction in which the slide gear meshes with the outer gear is installed between the diaphragm and the spring retainer, and the elasticity of the diaphragm by reducing the pressure in the two-wheel drive side negative pressure chamber Due to the deformation, the slide gear is moved in the direction in which the engagement with the outer gear is released to switch to the two-wheel drive, and the permanent magnet keeps the switching state to the two-wheel drive by the action of magnetically attracting the spring retainer. The sliding gear is moved to a position where it is meshed with the outer gear by elastic deformation of the diaphragm due to the decompression of the negative pressure chamber, and the four-wheel drive is switched by the action of the spring biasing the diaphragm toward the outer gear. In a freewheel hub that is designed to hold
A freewheel hub characterized in that a guide means for sliding and guiding the spring retainer in the axial direction is provided between the diaphragm cover and the spring retainer.   The guide means includes a guide cylinder provided at the center of the diaphragm cover, and a circular protrusion provided on a spring retainer and slidably fitted into the guide cylinder when switching to two-wheel drive. The freewheel hub according to claim 1.   The freewheel hub according to claim 2, wherein a chamfer is formed at a crossing portion between a front end surface and an outer diameter surface of the guide tube.   The freewheel hub according to claim 2, wherein a chamfer is formed on an outer peripheral portion of an end surface of the circular protrusion.   The freewheel hub according to any one of claims 2 to 4, wherein the circular protrusion is a head portion of a rivet that is inserted through a central portion of the connecting member and a spring retainer and integrally couples the two members. .   The freewheel hub according to claim 5, wherein the rivet is made of a non-magnetic material.   The freewheel hub according to claim 6, wherein the non-magnetic material is made of one of aluminum and stainless steel.   The freewheel hub according to any one of claims 2 to 4, wherein the circular projecting portion includes a plurality of cut and raised pieces arranged on the same circle centered on the axis of the spring retainer.

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