JP2018039320A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably keep a drive change-over state of a four-wheel drive vehicle.SOLUTION: A power transmission device comprises: a shaft 11 which is provided with a slide gear 19 which is relatively movable in an axial direction and is integrally rotatable around an axis, and is rotated around the axis by a driving force from a driving source 1; a hub 12 which is provided with an outer gear 20 which can be engaged with the slide gear 19 and is rotatable around the axis integrally to the hub, and is rotated around the axis together with a wheel 9; and a transmission cutoff mechanism 13 which relatively moves the slide gear 19 in the axial direction with respect to the shaft 11, and engages the slide gear 19 with the outer gear 20 thereby enabling rotation transmission between the shaft 11 and the hub 12, and on the other hand, which releases the engagement thereby cutting off the rotation transmission. The transmission cutoff mechanism 13 has: a yoke 31 to which a magnetic force is given by a magnet 35; a suction member 32 which is sucked to the yoke 31 when releasing the engagement; and an inclination correction mechanism 33 which corrects relative inclination in the axial direction between the yoke 31 and the suction member 32.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power transmission device having a freewheel function.

  In a four-wheel drive vehicle, for example, as shown in Patent Document 1, a two-wheel drive state and a four-wheel drive state can be switched, and in a two-wheel drive state, a driven wheel is disconnected from a driven axle. The free wheel that cuts off the running resistance received from the driven wheel while the four-wheel drive state allows the driven wheel and the driven axle to be locked, and allows the driving force from the engine to be transmitted to the driven wheel. A power transmission device having a function may be employed.

  This type of power transmission device is employed, for example, in a four-wheel drive vehicle shown in FIG. The four-wheel drive vehicle includes a transfer 5 that can be switched between a two-wheel drive state and a four-wheel drive state by operating a switching mechanism 4 with an engine 1, a transmission 2, and a transfer lever 3. In the two-wheel drive state, the driving force is transmitted from the transfer 5 to the rear wheel 9b via the rear propeller shaft 6b, the rear differential 7b, and the rear axle 8b. Transmission of driving force from the transfer 5 to the front propeller shaft 6a is interrupted. On the other hand, in the four-wheel drive state, as in the two-wheel drive state, the driving force is transmitted to the rear wheel 9b, and the front propeller shaft 6a, the front differential 7a, the front axle 8a (shaft) are transferred from the transfer 5. 11) and the driving force is also transmitted to the front wheels 9a via the power transmission device 100.

  As shown in FIGS. 8 and 9, the power transmission device 100 includes a shaft 101 that rotates around an axis by a driving force from the engine 1, a hub 102 that rotates around the axis together with wheels 9 a (see FIG. 2), A transmission blocking mechanism 103 capable of connecting / blocking rotation transmission between the shaft 101 and the hub 102 is a main component. The shaft 101 and the transmission blocking mechanism 103 are accommodated in a hub 102 and a cover 104 and a spindle 105 provided integrally with the hub 102. A slide gear 106 is provided on the shaft 101 so as to be relatively movable in the axial direction and integrally rotatable around the axis. The hub 102 is provided with an outer gear 107 that can be engaged with the slide gear 106 so as to be integrally rotatable about an axis.

  The transmission cutoff mechanism 103 moves the slide gear 106 relative to the shaft 101 in the axial direction, and engages the slide gear 106 and the outer gear 107 to enable transmission of rotation between the shaft 101 and the hub 102. On the other hand, it has a function of releasing the engagement between the slide gear 106 and the outer gear 107 and blocking the rotation transmission.

  The transmission cutoff mechanism 103 is provided with a diaphragm 110 that partitions the internal space (negative pressure chamber) of the transmission cutoff mechanism 103 into a two-wheel drive negative pressure chamber 108 and a four-wheel drive negative pressure chamber 109. The two-wheel drive negative pressure chamber 108 is connected to the two-wheel drive negative pressure port 112 via the two-wheel drive negative pressure path 111, and the four-wheel drive negative pressure chamber 109 is four-wheel driven via the four-wheel drive negative pressure path 113. Each is connected to the negative pressure port 114. A disk-shaped pressure receiving plate 115 made of a magnetic material is provided on the two-wheel drive negative pressure chamber 108 side of the diaphragm 110, and a piston 116 is provided on the four-wheel drive negative pressure chamber 109 side. The diaphragm 110, the pressure receiving plate 115, and the piston 116 are integrated by a rivet 117, and the pressure receiving plate 115 and the piston 116 move in the axial direction as the diaphragm 110 moves in the axial direction. .

  A yoke 118 made of a magnetic material is fixed inside the cover 104, and a cylindrical adsorption portion 118 a that stands so as to face the pressure receiving plate 115 is formed at the inner peripheral end of the yoke 118. The yoke 118 is provided with a magnet 119, and the magnet 119 imparts magnetism to the yoke 118 (adsorption portion 118 a). A coil spring 120 is interposed between the yoke 118 and the pressure receiving plate 115. The coil spring 120 urges the pressure receiving plate 115 (diaphragm 110, piston 116) in a direction to separate from the yoke 118. A slide gear 106 is provided on the outer peripheral edge side of the piston 116 so as to be integrally movable in the axial direction. As the piston 116 moves in the axial direction, the slide gear 106 also moves in the same direction.

  In the two-wheel drive state (see FIG. 8), the two-wheel drive negative pressure chamber 108 is in a negative pressure state, and the diaphragm 110 moves to the two-wheel drive negative pressure chamber 108 side. Along with this movement, the engagement between the slide gear 106 and the outer gear 107 is released and the transmission of the rotational force between the shaft 101 and the hub 102 is switched to the two-wheel drive state, and as shown in FIG. As described above, the pressure receiving plate 115 is attracted by the magnetic force to the attracting portion 118a of the yoke 118 having magnetism. When the switching to the two-wheel drive state is completed, the two-wheel drive negative pressure chamber 108 is opened to the atmosphere, and the two-wheel drive state is maintained only by the attraction force of the yoke 118.

  On the other hand, in the four-wheel drive state (see FIG. 9), the four-wheel drive negative pressure chamber 109 is in a negative pressure state, and the diaphragm 110 moves to the four-wheel drive negative pressure chamber 109 side. Along with this movement, the slide gear 106 and the outer gear 107 are engaged to switch to the four-wheel drive state in which the rotational force can be transmitted from the shaft 101 to the hub 102. When the switching to the four-wheel drive state is completed, the four-wheel drive negative pressure chamber 109 is opened to the atmosphere, and the four-wheel drive state is maintained only by the urging force of the coil spring 120.

  As described above, the seal materials 121, 122, which secure the airtightness of the negative pressure chambers 108, 109 by opening the negative pressure chambers 108, 109 to the atmosphere together with the switching to the two-wheel drive state or the four-wheel drive state. A load is always applied to 123, and the deterioration thereof is prevented, and muddy water is prevented from being sucked into the apparatus by negative pressure.

Japanese Patent Laid-Open No. 10-278621

  The yoke employed in the configuration according to Patent Document 1 (and FIG. 8) is a magnetic material that is magnetized by an attached magnet, and cannot function as a yoke if the magnetism changes in the processing process. . For this reason, the processing of the yoke is not performed by turning, but is performed by pressing that hardly affects the magnetism. However, in press processing, it is difficult to ensure high processing accuracy as compared with turning processing, and the processing accuracy of the adsorption portion of the yoke that adsorbs the pressure receiving plate may be insufficient. In this case, the pressure receiving plate and the suction portion are relatively inclined in the axial direction, and the pressure receiving plate cannot be sucked over the entire circumference of the annular suction portion, so that the two-wheel drive state is stably maintained. There is a possibility that it cannot be done.

  Therefore, an object of the present invention is to stably maintain the drive switching state of the four-wheel drive vehicle.

  In order to solve this problem, in the present invention, the slide gear is provided so as to be relatively movable in the axial direction and to be integrally rotatable around the axis, and the shaft rotates around the axis by the driving force from the driving source, An outer gear that can be engaged with a slide gear is provided so as to be integrally rotatable around an axis, and a hub that rotates around the axis together with a wheel, and the slide gear is moved relative to the shaft in the axial direction, and the slide gear And the outer gear are engaged to enable transmission of rotation between the shaft and the hub, while the engagement of the slide gear and the outer gear is released to interrupt the rotation transmission. The transmission blocking mechanism is provided on one side of the shaft side or the hub side and is provided with a magnetic force by a magnet, and the shaft side or Provided on the other side of the hub side, which is attracted to the yoke when the engagement is released, and is deformed by the attraction force of the attraction member to the yoke, so that the yoke and the attraction member A power transmission device having an inclination correction mechanism that corrects the relative inclination in the axial direction and uniformly adsorbs the adsorbing member in the entire adsorbing portion of the yoke is configured.

  Thus, by correcting the relative inclination of the yoke and the suction member in the axial direction, the suction member can be reliably sucked by the yoke. For this reason, the drive switching state (four-wheel drive state or two-wheel drive state) of the four-wheel drive vehicle can be stably maintained.

  In the above configuration, the transmission blocking mechanism includes an engagement negative pressure chamber that generates a negative pressure when the suction member is driven in the axial direction, an engagement negative pressure chamber that generates a negative pressure when the engagement is performed, and the engagement. A diaphragm that divides into a release negative pressure chamber that becomes a negative pressure at the time of release, a biasing member that biases the diaphragm toward the engagement negative pressure chamber, a fixed member that moves in the axial direction together with the diaphragm, It is preferable to further include As described above, the release negative pressure chamber and the engagement negative pressure chamber are formed by the diaphragm, and the engagement state and the engagement release state are switched by the negative pressure, so that the switching can be easily performed.

  When the transmission blocking mechanism is configured as described above, it is preferable that the tilt correction mechanism is an elastic member interposed between the adsorption member and the fixing member. By using the elastic member in this way, the function of the tilt correction mechanism can be surely exhibited.

  In the configuration employing the elastic member, it is preferable that this elastic member is a wave spring or a disc spring, since these springs have a simple structure and are less likely to cause problems, and thus have high reliability. The function of the tilt correction mechanism can be reliably exhibited and the cost can be reduced.

  A power transmission device according to the present invention includes a tilt correction mechanism that corrects a relative tilt in the axial direction between the yoke and the suction member in a transmission blocking mechanism that connects or blocks rotation transmission between the shaft and the hub. Since it employ | adopted, an adsorption | suction member can be reliably adsorb | sucked with a yoke. For this reason, the drive switching state of the four-wheel drive vehicle can be stably maintained.

A longitudinal sectional view showing one embodiment of a power transmission device according to the present invention Overall configuration diagram showing an example of a four-wheel drive vehicle employing the power transmission device shown in FIG. It is a longitudinal cross-sectional view which shows the principal part of an inclination correction mechanism, Comprising: When (a) employs a wave spring as an elastic member, (b) employs a disc spring 1 is a longitudinal sectional view showing a main part of the power transmission device shown in FIG. 1 (two-wheel drive state). 1 is a longitudinal sectional view showing a main part of the power transmission device shown in FIG. 1 (four-wheel drive state). A longitudinal sectional view showing the main part of the tilt correction mechanism (when there is no relative tilt in the axial direction between the yoke and the pressure receiving plate) Longitudinal sectional view showing the main part of the tilt correction mechanism (when there is a relative tilt in the axial direction between the yoke and the pressure receiving plate) A longitudinal sectional view showing an example (two-wheel drive state) of a power transmission device according to the prior art A longitudinal sectional view showing an example of a power transmission device according to the prior art (four-wheel drive state) The longitudinal cross-sectional view which shows the principal part of the power transmission device shown in FIG.

  An embodiment of a power transmission device 10 according to the present invention is shown in FIG. This power transmission device is employed, for example, in a four-wheel drive vehicle shown in FIG. As described above, this four-wheel drive vehicle is a transfer that can switch between the two-wheel drive state and the four-wheel drive state by operating the switching mechanism 4 with the engine 1, the transmission 2, and the transfer lever 3. 5 is provided.

  In the two-wheel drive state, the driving force is transmitted from the transfer 5 to the rear wheel 9b via the rear propeller shaft 6b, the rear differential 7b, and the rear axle 8b. Transmission of driving force from the transfer 5 to the front propeller shaft 6a is interrupted. On the other hand, in the four-wheel drive state, as in the two-wheel drive state, the driving force is transmitted to the rear wheel 9b, and the front propeller shaft 6a, the front differential 7a, the front axle 8a (shaft) are transferred from the transfer 5. 11) and the driving force is also transmitted to the front wheels 9a via the power transmission device 10.

  The power transmission device 10 includes a shaft 11 that rotates around an axis by a driving force of an engine as a driving source 1 (hereinafter, the same reference numeral as the driving source 1) and a wheel 9a (see FIG. 2). The main component is a hub 12 that rotates around, and a transmission blocking mechanism 13 that can connect and block rotation transmission between the shaft 11 and the hub 12. The shaft 11 and the transmission blocking mechanism 13 are accommodated in a hub 12 and a cover 14 and a spindle 15 provided integrally with the hub 12. The hub 12 and the cover 14 are integrally fastened by bolts 16. A bearing 17 is provided between the hub 12 and the spindle 15 so that the hub 12 and the spindle 15 can rotate relative to each other around an axis. Further, the shaft 11 is provided with a bush 18 so that the shaft 11 can smoothly rotate around the axis with respect to the spindle 15.

  A slide gear 19 is provided on the shaft 11. The shaft 11 is formed with a guide groove 11a, and the slide gear 19 is formed with a guide projection 19a guided by the guide groove 11a. The slide gear 19 can move relative to the shaft 11 in the axial direction and can be moved around the axis. Integral rotation is possible. The hub 12 is provided with an outer gear 20 that can be engaged with the slide gear 19 so as to rotate integrally with the hub 12 around the axis.

  The transmission blocking mechanism 13 engages the slide gear 19 and the outer gear 20 by moving the slide gear 19 relative to the shaft 11 in the axial direction, and enables rotation transmission between the shaft 11 and the hub 12. On the other hand, it has the function of releasing the engagement between the slide gear 19 and the outer gear 20 and blocking the rotation transmission.

  The transmission cutoff mechanism 13 has a two-wheel drive as a release negative pressure chamber 21 in which the internal space (negative pressure chamber) of the transmission cutoff mechanism 13 becomes negative when the engagement between the slide gear 19 and the outer gear 20 is released. A negative pressure chamber (hereinafter, the same sign as that of the release negative pressure chamber 21), and the engagement negative pressure chamber 22 that becomes negative pressure when the slide gear 19 and the outer gear 20 are engaged are negatively driven by four wheels. A diaphragm 23 is provided for partitioning into a pressure chamber (in the following, the same reference numeral as that of the engagement negative pressure chamber 22 is given).

  The two-wheel drive negative pressure chamber 21 is connected to a two-wheel drive negative pressure port 25 via a two-wheel drive negative pressure path 24, and the four-wheel drive negative pressure chamber 22 is four-wheel driven via a four-wheel drive negative pressure path 26. Each is connected to a negative pressure port 27. The two-wheel drive negative pressure path 24 and the four-wheel drive negative pressure path 26 are provided with timer-controlled shut-off valves (not shown). This shut-off valve is activated when the negative pressure of the two-wheel drive negative pressure path 24 or the four-wheel drive negative pressure path 26 has passed a predetermined time set in advance by a timer, and the two-wheel drive negative pressure chamber in a negative pressure state. The 21 or 4-wheel drive negative pressure chamber 22 is opened to the atmosphere.

  A pressure receiving plate 28 is provided on the two-wheel drive negative pressure chamber 21 side of the diaphragm 23, and a piston 29 is provided on the four-wheel drive negative pressure chamber 22 side. A fixing member 30 having an S-shaped circumferential cross section is provided on the pressure receiving plate 28 on the two-wheel drive negative pressure chamber 21 side. An adsorbing member 32 that is adsorbed by a yoke 31 described later when the engagement between the slide gear 19 and the outer gear 20 is released is provided on the outer peripheral end of the fixing member 30.

  Between the fixed member 30 and the adsorption member 32, an elastic member functioning as the inclination correction mechanism 33 (hereinafter, the same reference numeral as the inclination correction mechanism 33 is attached) is interposed. That is, the adsorbing member 32 is floating-fixed to the fixing member 30 by the elastic member 33 (fixed so as to be inclined with respect to the fixing member 30 when an external force is applied). As the elastic member 33, a wave spring 33a shown in FIG. Or the disc spring 33b shown in FIG.3 (b) can also be employ | adopted instead of the wave spring 33a. Since the wave spring 33a and the disc spring 33b have a simple structure and are less likely to cause problems and have high reliability, the function as the tilt correction mechanism 33 can be reliably exerted and the cost can be reduced.

  The diaphragm 23, the pressure receiving plate 28, the piston 29, and the fixing member 30 are integrated by a rivet 34. As the diaphragm 23 moves in the axial direction, the pressure receiving plate 28, the piston 29, the fixing member 30, and The elastic member 33 and the adsorbing member 32 provided on the fixing member 30 are integrally moved in the axial direction.

  A yoke 31 made of a magnetic material is fixed inside the cover 14, and an annular adsorbing portion 31 a that stands so as to face the pressure receiving plate 28 is formed at the inner peripheral end of the yoke 31. The yoke 31 is provided with a magnet 35, and the magnet 35 imparts magnetism to the yoke 31 (attracting portion 31 a). Between the yoke 31 and the pressure receiving plate 28, a coil spring (hereinafter referred to as the urging member 36) is interposed as an urging member 36. The coil spring 36 urges the pressure receiving plate 28 (the diaphragm 23, the fixing member 30, the elastic member 33, the suction member 32, and the piston 29) in a direction in which the pressure receiving plate 28 is separated from the yoke 31. A slide gear 19 is provided on the outer peripheral edge side of the piston 29 so as to be integrally movable in the axial direction. As the piston 29 moves in the axial direction, the slide gear 19 also moves in the same direction.

  When the two-wheel drive negative pressure chamber 21 is in a negative pressure state, the diaphragm 23 moves to the two-wheel drive negative pressure chamber 21 side as shown in FIG. With this movement, the engagement between the slide gear 19 and the outer gear 20 is released, and the two-wheel drive state in which the transmission of the rotational force between the shaft 11 and the hub 12 is interrupted is switched. When a predetermined time elapses after the switching, a timer provided in the two-wheel drive negative pressure path 24 is activated and the two-wheel drive negative pressure chamber 21 is opened to the atmosphere. The attracting member 32 is attracted to the attracting portion 31a of the magnetic yoke 31 by a magnetic force, and the two-wheel drive state is maintained only by this attracting force.

  On the other hand, when the four-wheel drive negative pressure chamber 22 is in a negative pressure state, the diaphragm 23 moves to the four-wheel drive negative pressure chamber 22 side as shown in FIG. Along with this movement, the slide gear 19 and the outer gear 20 are engaged to switch to the four-wheel drive state in which the rotational force can be transmitted from the shaft 11 to the hub 12. When a predetermined time elapses after the switching, a timer provided in the four-wheel drive negative pressure path 26 is activated and the four-wheel drive negative pressure chamber 22 is opened to the atmosphere. The four-wheel drive state is maintained only by the urging force of the coil spring 36.

  As described above, the two-wheel drive negative pressure chamber 21 and the four-wheel drive negative pressure chamber 22 are opened to the atmosphere together with the switching to the two-wheel drive state or the four-wheel drive state, so that the negative pressure chambers 21 and 22 are airtight. It is possible to prevent as much as possible that a load is always applied to the sealing materials 37, 38, 39 to be secured, and that the deterioration of the sealing materials 37, 38, 39 progresses or that the muddy water is sucked into the apparatus by negative pressure.

  The yoke 31 is a magnetic material that is magnetized by the magnet 35 provided therewith. If the magnetism changes in the processing step, the function as the yoke 31 cannot be exhibited. For this reason, the processing of the yoke 31 is not performed by turning, but is performed by pressing that hardly affects the magnetism. If the press working accuracy is sufficient, the suction member 32 can be sucked in the entire circumferential direction of the suction portion 31a of the yoke 31 in the two-wheel drive state as shown in FIG. However, in press processing, it is difficult to ensure high processing accuracy as compared with turning processing, and processing accuracy of the suction portion 31a of the yoke 31 may be insufficient, and the yoke 31 and the suction member 32 are each in the axial direction. If it is provided on the rigid, there is a possibility that a stable adsorption state cannot be obtained.

  On the other hand, as shown in FIG. 7, the elastic member 33 is interposed between the fixing member 30 and the suction member 32 as in the configuration according to the present embodiment, so that the yoke 31 and the suction member 32 are interposed. The elastic member 33 is deformed by the attraction force, the axial relative inclination between the yoke 31 and the attraction member 32 is corrected, and the attraction member 32 can be reliably adsorbed by the yoke 31. For this reason, the switching state of the drive mechanism (in this configuration, the two-wheel drive state) can be stably maintained.

  The power transmission device 10 according to the above embodiment is merely an example, and solves the problem of the present invention that stably maintains the drive switching state (two-wheel drive state or four-wheel drive state) of a four-wheel drive vehicle. As long as it is possible, the shape, arrangement, and the like of each component can be changed as appropriate.

1 Drive source (engine)
9 (9a) Wheel (front wheel)
11 Shaft 12 Hub 13 Transmission blocking mechanism 19 Slide gear 20 Outer gear 21 Release negative pressure chamber (two-wheel drive negative pressure chamber)
22 engagement negative pressure chamber (four-wheel drive negative pressure chamber)
23 Diaphragm 30 Fixed member 31 Yoke 31a Suction part 32 Suction member 33 Inclination correction mechanism (elastic member)
33a wave spring 33b disc spring 35 magnet 36 biasing member (coil spring)

Claims (4)

A shaft (11) that rotates around an axis by a driving force from a drive source (1), the slide gear (19) is provided so as to be relatively movable in the axial direction and integrally rotatable around the axis;
A hub (12) that rotates around an axis together with a wheel (9), wherein an outer gear (20) that can be engaged with the slide gear (19) is provided so as to rotate integrally around the axis;
The slide gear (19) is moved relative to the shaft (11) in the axial direction, the slide gear (19) and the outer gear (20) are engaged, and the shaft (11) and the hub ( 12), a transmission blocking mechanism (13) for releasing the engagement between the slide gear (19) and the outer gear (20) and blocking the rotation transmission,
The transmission cutoff mechanism (13)
A yoke (31) provided on one side of the shaft (11) side or the hub (12) side, to which a magnetic force is applied by a magnet (35);
An adsorbing member (32) provided on the other side of the shaft (11) side or the hub (12) side and adsorbed by the yoke (31) when the engagement is released;
The yoke (31) is deformed by the attracting force of the attracting member (32) to correct the relative inclination in the axial direction of the yoke (31) and the attracting member (32). ) And an inclination correction mechanism (33) for adsorbing the adsorbing member (32) evenly throughout the adsorbing part (31a);
A power transmission device. The transmission blocking mechanism (13)
An engagement negative pressure chamber (22) that generates a negative pressure when the suction member (32) is driven in the axial direction, an engagement negative pressure chamber (22) that generates a negative pressure when the engagement is performed, and when the engagement is released A diaphragm (23) for partitioning into a release negative pressure chamber (21) for generating a negative pressure;
An urging member (36) for urging the diaphragm (23) toward the engagement negative pressure chamber (22);
A fixed member (30) that moves axially with the diaphragm (23);
The power transmission device according to claim 1, further comprising:   The power transmission device according to claim 2, wherein the inclination correction mechanism (33) is an elastic member (33) interposed between the suction member (32) and the fixing member (30).   The power transmission device according to claim 3, wherein the elastic member (33) is a wave spring (33a) or a disc spring (33b).

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