JP2003324895A - Arrangement for switching between two-wheel drive and four-wheel drive and actuator for driving such - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized, inexpensive actuator wherein the number of parts constituting a waiting mechanism is reduced and the assembling workability is enhanced. <P>SOLUTION: The actuator 20 comprises an output shaft 23 coupled with a drive gear 32; a pair of cam followers 26 and 28 which are rotated by the shaft 23 and drive cams 13 and 15 on driven shafts 11 and 12; coil springs 35 housed in housing portions 33 for the drive gear 32; a rotation retaining plate 31 held on the output shaft 23 so that the retaining plate 31 cannot be relatively rotated; a plurality of spring pressing portions 31b protrudingly formed on the retaining plate 31; and slits 34 for preventing interference with the pressing portions 31b. The rotation of the drive gear 32 is transmitted to the output shaft 23 through the springs 35 and the rotation retaining plate 31. If the output shaft 23 is arrested and stopped and the drive gear 32 continues rotating, either the ends 35a and 35b of each spring 35 is pressed by the pressing portions 31b. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-wheel drive and four-wheel drive switching device for an automobile, which is suitable for a part-time four-wheel drive vehicle (4WD) and the like, and an actuator for driving the same.

[0002]

2. Description of the Related Art A part-time four-wheel drive vehicle (4WD) capable of driving four wheels only when necessary in a two-wheel drive vehicle is known, and two-wheel drive and four-wheel drive of this part-time four-wheel drive vehicle are known. In the switching device, the two-wheel drive and four-wheel drive switching shafts and four
It is known that the wheel speed switching shaft is selectively driven by an actuator to switch to four driving states of two-wheel drive, four-wheel high-speed drive, four-wheel neutral and four-wheel low-speed drive.

[0003]

In the conventional actuator, when the two-wheel drive state is switched to the four-wheel drive state, the two output gears for the rear wheels and the front drive gear are out of phase with each other. The two-wheel / four-wheel switching slider does not allow spline fitting of both gears, or the power required to release the spline fitting of both gears is too large when switching from four-wheel drive to two-wheel drive. In some cases, the spline fitting of both gears cannot be released, and as a countermeasure against this, it is known that a waiting mechanism is provided to wait until the timing at which both gears mesh or the timing at which they disengage. As this conventional example, for example, Japanese Patent Laid-Open No. 7-179138.
Although there is a technique disclosed in the publication, the waiting mechanism disclosed in this publication includes a spiral spring, first and second plates, and a bush member, so that the number of parts is large and the assembly workability is poor, Also, the waiting mechanism is large, and thus the entire actuator is large.

Therefore, the present invention has been made to solve the above-mentioned problems, and to provide a compact and inexpensive actuator by reducing the number of parts constituting the waiting mechanism to improve the assembling workability. With the goal.

[0005]

According to a first aspect of the present invention, there are provided two driven shafts arranged in parallel with each other and movable in the axial direction, and driven shaft drives attached to the respective driven shafts. Cams and the respective cams are driven to predetermined stop positions which are predetermined according to the mode by the switching operation of the operation switch having a plurality of switching modes, and the driven shafts are selectively rotated. In the actuator moved by a predetermined stroke in the direction, the actuator is
A motor that rotates normally or reversely when energized, a drive gear that meshes with a worm formed on an armature shaft of the motor, an output shaft that is connected to the drive gear, and the output shaft that is rotated by the rotation of the output shaft. A pair of cam followers engaged with the respective cams to drive the respective cams, and a plurality of spring accommodating portions formed on the same circumference of the drive gear and at predetermined intervals in the circumferential direction, are housed respectively. Each coil spring, a rotation holding plate held by the output shaft so as not to rotate relative to each other, and a plurality of spring pressing portions formed on the rotation holding plate so as to press either one of both ends of each coil spring. A slit formed between the spring accommodating portions of the drive gear for preventing interference with the spring pressing portions, the drive gear and the rotation holding plate. And a first actuator case accommodating the output shaft, and a second actuator fixed to the first actuator case, supporting the driven shafts axially movably and accommodating the cams. A case is provided, and the rotation of the drive gear is transmitted to the output shaft through the coil springs and the rotation holding plate, and the output shaft is stopped midway and stopped to rotate the drive gear. When continuing, it is characterized in that one of the both ends of each coil spring is pressed by each spring pressing portion of the rotation holding plate.

According to a second aspect of the present invention, in the actuator according to the first aspect, the plurality of spring accommodating portions formed in the drive gear are arc-shaped and are formed at equal intervals in a circumferential direction of the drive gear. In addition to the three spring storage portions, each of the coil springs is a cylindrical compression coil spring.

According to a third aspect of the present invention, two-wheel drive and four-wheel drive switching shafts and four-wheel speed switching shafts, which are arranged parallel to each other in the transfer and are movable in the axial direction, are provided respectively on the switching shafts. Each of the above-mentioned cams in the two-wheel drive and four-wheel drive switching device provided with the mounted switching shaft driving cam is set at a predetermined stop position in accordance with the mode by the switching operation of the mode switching operation switch. 2 wheels drive, 4 wheels high speed drive, 4 wheels neutral and 4 shafts by selectively moving each switching shaft by a predetermined stroke in the axial direction.
In a two-wheel drive and four-wheel drive switching device drive actuator that is selectively switched between four low-speed wheel drive states, the actuator includes a motor that rotates normally or reversely when energized, and an armature of the motor. A drive gear that meshes with a worm formed on the shaft, an output shaft that is connected to the drive gear, and a pair of drive shafts that are rotated by the rotation of the output shaft and that engage with the cams and drive the cams. A cam follower, coil springs respectively housed in a plurality of spring housings formed on the same circumference of the drive gear and at a predetermined interval in the circumferential direction, and non-rotatably held by the output shaft. A rotation holding plate, and a plurality of spring pressing portions projectingly formed on the rotation holding plate and capable of pressing either one of both ends of each coil spring, A slit formed between the spring housing portions of the drive gear for preventing interference with the spring pressing portions, and a first actuator case housing the drive gear, the rotation holding plate, and the output shaft, respectively. A second actuator case fixed to the first actuator case, movably supporting the switching shafts in the axial direction and accommodating the cams, the rotation of the drive gear Each spring pressing portion of the rotation holding plate is transmitted to the output shaft through a spring and the rotation holding plate, and when the output shaft is stopped in the middle and stopped and the drive gear continues to rotate. Is used to press either one of both ends of each coil spring.

According to a fourth aspect of the present invention, there is provided the actuator for driving the two-wheel drive and four-wheel drive switching device according to the third aspect, wherein the plurality of spring accommodating portions formed in the drive gear are provided in the drive gear. It is characterized in that it has three arc-shaped spring accommodating portions formed at equal intervals in the circumferential direction, and each coil spring is three cylindrical compression coil springs.

According to a fifth aspect of the present invention, two-wheel drive and four-wheel drive switching shafts and four-wheel speed switching shafts, which are arranged parallel to each other in the transfer and are movable in the axial direction, are provided respectively on the switching shafts. A cam for switching shaft drive attached,
An actuator that is rotationally driven to a predetermined stop position that is predetermined according to the mode by the switching operation of the mode switching operation switch and that drives the cams to selectively move the switching shafts by a predetermined stroke in the axial direction. A two-wheel drive, four-wheel drive, four-wheel high-speed drive, four-wheel neutral, and four-wheel low-speed drive. A motor that rotates normally or reversely when energized, a drive gear that meshes with a worm formed on an armature shaft of the motor, an output shaft that is connected to the drive gear, and the output shaft that is rotated by the rotation of the output shaft. A pair of cam followers that engage with the cams to drive the cams, and a plurality of cam followers formed on the same circumference of the drive gear and at a predetermined interval in the circumferential direction. Each of the coil springs housed in the spring housing portion, the rotation holding plate held by the output shaft so as not to rotate relative to each other, and the one end of each coil spring protrudingly formed on the rotation holding plate are pressed. A plurality of possible spring pressing portions, slits formed between the spring housing portions of the drive gear for preventing interference with the spring pressing portions, the drive gear, the rotation holding plate, and the output shaft. And a second actuator case that is fixed to the first actuator case and that supports the switching shafts movably in the axial direction and that houses the cams. The rotation of the drive gear is transmitted to the output shaft via the coil springs and the rotation holding plate, and When the force shaft is restrained in the middle and stopped, and the drive gear continues to rotate, each spring pressing portion of the rotation holding plate presses one of both ends of each coil spring. To do.

A sixth aspect of the present invention is the two-wheel drive and four-wheel drive switching device according to the fifth aspect, wherein the plurality of spring accommodating portions formed in the drive gear are arranged in a circumferential direction of the drive gear. In addition to three arc-shaped spring accommodating portions formed at equal intervals, the coil springs are three cylindrical compression coil springs.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a two-wheel drive and a four-wheel drive according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a main part of an actuator used in a wheel drive switching device, FIG. 2 is a perspective view of the actuator seen from the back side, FIG. 3 is a plan view showing a part of the actuator in cross section, and FIG. FIG. 5 is a plan view showing a state in which the rotation holding plate is removed, FIG. 5 is an exploded perspective view showing the relationship between the rotation holding plate, the drive gear and the output shaft of the actuator, FIG. 6 is a bottom view of the rotation holding plate, and FIG. FIG. 8 is a perspective view of the output shaft.
Is a bottom view of the same output shaft, and FIG. 9 is a schematic configuration diagram of a part-time four-wheel drive vehicle using the two-wheel drive and four-wheel drive switching device.
FIG. 10 is an explanatory diagram showing a two-wheel drive state of the same two-wheel drive and four-wheel drive switching device, and FIG. 11 is an explanatory diagram showing a four-wheel high-speed drive state of the same two-wheel drive and four-wheel drive switching device. 12 is an explanatory view showing a four-wheel neutral state of the two-wheel drive and four-wheel drive switching device, and FIG. 13 is an explanatory diagram showing a four-wheel low-speed drive state of the two-wheel drive and four-wheel drive switching device, FIG. FIG. 15 is a plan view showing a waiting mechanism at the time of forward rotation of the actuator in a partial cross section, and FIG. 15 is a plan view showing a waiting mechanism at the time of reverse rotation of the actuator in a partial section.

As shown in FIG. 9, a part-time four-wheel drive vehicle (4WD) 1 is provided with an engine 2, a transmission (transmission) 3, and a transfer 4. A switching device 10 for switching between two-wheel drive and four-wheel drive is attached to the transfer 4. And this part time 4
FIG. 10 shows a two-wheel drive and four-wheel drive switching shaft 11 as a driven shaft and a four-wheel speed switching shaft 12 as a driven shaft, which are arranged in parallel in the transfer 4 during normal traveling of the WD 1. Two wheel drive (2
The state is H). In this case, the power of the engine 2 is generated by the transfer 4 for the rear wheel output shaft 5 and the rear wheel differential 6.
It is transmitted to the rear wheels 7B and 7B via B, and the two wheels are driven by the rear wheels 7B and 7B.

Further, as shown in FIG. 11, two-wheel drive and four-wheel drive are used.
When the two-wheel drive / four-wheel drive switching shaft 11 is moved by a predetermined stroke in the axial direction by the wheel drive switching device 10, the four-wheel high-speed drive (4H) state is set, and the rear-wheel output shaft gear 5a and the front drive gear. A two-wheel / four-wheel switching slider 9 that intermittently engages with the front drive gear 8a engages with the front drive gear 8a (spline fitting). As a result, the power of the engine 2 is not limited to the rear wheels 7B and 7B,
The front wheels 7A, 7 through the front wheel output shaft 8 and the front wheel differential 6A
It is transmitted to A and the four wheels are driven at high speed by the front and rear wheels 7A and 7B.

Further, as shown in FIG. 12, when the four-wheel speed switching shaft 12 is moved by a predetermined stroke in the axial direction by the two-wheel drive and four-wheel drive switching device 10, it is switched to a four-wheel neutral (N) state. In addition, from the state of the four-wheel neutral,
As shown in FIG. 3, when the four-wheel speed switching shaft 12 is further moved by a predetermined stroke in the axial direction by the two-wheel drive and four-wheel drive switching device 10, the state is switched to the four-wheel low speed drive (4L) state. There is.

Next, a two-wheel drive / four-wheel drive switching shaft 11 and a four-wheel speed switching shaft 1 arranged in parallel in the transfer 4.
The two switching shafts 11 and 12 are moved in the axial direction by a predetermined stroke to drive the two-wheel drive (2H) and the four-wheel high speed drive (4
H), four-wheel neutral (N), and four-wheel low-speed drive (4L) will be described.

As shown in FIGS. 1 to 13, the actuator 20 includes a rotary plate 24 fixed to the output shaft 23 of the actuator 20 and rotating integrally with the output shaft 23.
The rotary plate 24 is provided with a pair of rollers 26 and 28 rotatably supported as cam followers. The pair of rollers 26 and 28 are mounted on the two-wheel drive and four-wheel drive switching shafts 11 and four-wheel speed switching shafts 12 serving as the driven shafts, respectively.
The cams 13 and 15 are driven by engaging with a pair of cams 13 and 15 that drive the cams 1 and 12, respectively.

Further, the actuator 20 includes a motor 36 that rotates forward or backward when energized, and the motor 3
A worm 38 formed on the armature shaft 37 of 6;
A drive gear 32 that meshes with the worm 38 and is connected to the output shaft 23, a first actuator case 21 that houses the drive gear 32, the output shaft 23, and the rotary plate 24, and the first actuator. Case 21
And a second actuator case 21a which accommodates the cams 13 and 15 and supports the switching shafts 11 and 12 movably in the axial direction.

As shown in FIG. 1 and FIGS. 10 to 13, the pair of cams 13 and 15 includes the second actuator case 2
It is placed in the recess 18 of 1a. This pair of cams 13,
Reference numeral 15 is slidably supported by a support shaft 19 which is hung over the recess 18 with one end thereof penetrating. The second actuator case 21a is used for the transfer 4
It is attached via bolts (not shown),
It is attached to the first actuator case 21 via a bolt or the like not shown.

Further, cam grooves 14 and 16 having a predetermined shape are formed on the upper surfaces of the cams 13 and 15, respectively. Further, as shown in FIG. 10, convex portions 13a and 15a are integrally formed on the lower surfaces of the cams 13 and 15, respectively.
The convex portions 13a and 15a of the cams 13 and 15 are fitted in the concave portions 11a and 12a formed in the switching shafts 11 and 12, respectively. As a result, when one cam 13 slides on the support shaft 19, the switching shaft 11 for switching between two-wheel drive and four-wheel drive is moved by a predetermined stroke in the axial direction as the cam 13 slides. The other cam 15 is the support shaft 19.
When the cam 15 slides, the four-wheel speed switching shaft 12 moves in the axial direction by a predetermined stroke as the cam 15 slides.

As shown in FIGS. 2 to 5, the first actuator case 21 of the actuator 20 has a substantially central portion,
A circular hole-shaped opening 22 is formed. This opening 22
A disk-shaped rotary plate 24 fixed to the base end 23a of the output shaft 23 rotatably supported by the actuator case 21 by press fitting or the like is rotatably accommodated on the back side of the inside, and A drive gear 32, which is rotatably supported by the output shaft 23 via a rotation holding plate 31 which is relatively non-rotatably held by the tip 23b of the output shaft 23, is housed inside the opening 22. There is.

As shown in FIGS. 2, 7, and 8, the output shaft 2
On the back surface of the rotary plate 24 fixed to the base end 23a of the roller 3, the rollers (cam followers) 26,
28 is rotatably supported. One roller 26 is mounted at a position close to the rotation center 24a of the rotary plate 24, and the other roller 28 is mounted at a position far from the rotation center 24a of the rotary plate 24. Further, the one roller 26 and the other roller 28 are positioned at positions separated by an angle of 150 °.
The one roller 26 is connected to the cam groove 1 of the one cam 13.
4, the other roller 28 is provided with the cam groove 16 of the other cam 15.
Can be engaged with each other. Thereby, the rotary plate 24 rotated by the output shaft 23 of the actuator 20.
By the rotational movement of the rollers 26 and 28 provided in the above, the switching shafts 11 and 12 reciprocate in the axial direction by the predetermined strokes via the cams 13 and 15, respectively.

As shown in FIGS. 3 to 5, three concave spring accommodating portions 33 are formed on the same circumference of the upper surface of the gear body 32a of the drive gear 32 in an arc shape and at equal intervals. There is. A cylindrical compression coil spring 35 as a coil spring is housed in each spring housing portion 33. In addition, from both circumferential end surfaces 33a and 33b of one spring storage portion 33 to both circumferential end surfaces 33b and 3b of the other spring storage portion 33.
Slits 34 are formed from the upper surface of each gear body 32a between 3a to a predetermined depth. The slits 34 are for preventing interference with spring pressing portions 31b, which will be described later, provided on the rotation holding plate 31.

As shown in FIGS. 3, 5 and 6, a disk-shaped rotation holding plate 31 has a substantially oval-shaped mounting hole 31a in the center thereof.
At the same time, the lower surface of the outer peripheral edge of the rotation holding plate 31 is formed with three spring pressing portions 31b curved in an arc plate shape at equal intervals and integrally protruding downward. Each spring pressing portion 31b is normally located in each slit 34 of the drive gear 32. The mounting hole 31a of the rotation holding plate 31 is fitted into the tip 23b of the output shaft 23 of the actuator 20, and is prevented from coming off by the washer 39. Output shaft 2 of this actuator 20
3 and the rotation holding plate 31 are usually arranged as shown in FIG.
The rotation of the worm 38 of the armature shaft 37 of the motor 36 causes the drive gear 32 to rotate in the same direction as the direction in which the drive gear 32 rotates (for example, the forward rotation direction of arrow A in FIG. 3). However, when the motor 36 is energized and the output shaft 23 of the actuator 20 is restrained and stopped in the middle of the forward rotation or the reverse rotation, the drive gear 32 is rotated forward because the motor 36 continues to be energized. 14) or reverse rotation (direction of arrow C in FIG. 15). Therefore, either one of both ends 35a, 35b of each compression coil spring 35 is prevented from rotating by each spring pressing portion 31b of the rotation holding plate 31 that stops together with the output shaft 23, but both ends 35a, 35b are prevented from rotating. The other one is pressed by each spring pressing portion 31b, and each compression coil spring 35 is bent to be in a compressed state. When the compression coil springs 35 are in a compressed state, the drive gear 32 is restrained and stopped.

When the output shaft 23 of the actuator 20 is restrained and stopped, the two-wheel drive / four-wheel drive switching device 10 is used to move the two-wheel drive / four-wheel drive switching shaft 11 by a predetermined stroke in the axial direction. When switching from the two-wheel drive (2H) state to the four-wheel high-speed drive (4H) state, the two gears of the rear wheel output shaft gear 5a and the front drive gear 8a are out of phase and the two-wheel / four-wheel switching is performed. The spline fitting of both gears 5a and 8a cannot be performed by the slider 9, or the spline fitting of both gears 5a and 8a is released when switching from the four-wheel high speed drive (4H) state to the two-wheel drive (2H) state. There is a case that the spline fitting of the both gears 5a and 8a cannot be released due to too much power required for the rotation holding plate 31, the drive gear 32 and the compression coil spurs until the restrained state is released. By the action of the waiting mechanism 30 consisting of ring 35, as shown in FIG. 14 or FIG. 15, leaving the respective compression coil spring 35 in a compressed state.

When the two-wheel / four-wheel switching slide 9 matches the spline fitting phase of both gears 5a and 8a or the power required for releasing the spline fitting is reduced, the compressed state is established. The elastic repulsive force of each compression coil spring 35 allows the output shaft 23 to be automatically rotated in either one of the forward rotation direction and the reverse rotation direction via the rotation holding plate 31. It should be noted that the waiting mechanism 30 operates not only in the case of switching between 2H and 4H, but also in all the positions of 2H-4H-4L including the case of switching between 4H and 4L (four-wheel low speed drive). It has become.

Here, when the part-time 4WD1 is normal traveling, the two-wheel drive and four-wheel drive switching shafts 11 and four-wheel speed switching shafts 12 arranged in parallel in the transfer 4 are shown in FIG. In the two-wheel drive (2H) state, the power of the engine 2 is transmitted to the rear wheels 7B, 7B through the rear wheel output shaft 5 and the rear wheel differential 6B of the transfer 4, and the rear wheels 7B, Two-wheel drive by 7B is performed. At this time, as shown in FIG. 10, one roller 26 is engaged with the inner side of the cam groove 14 of the one cam 13. The other roller 28 is not engaged with the cam groove 16 of the other cam 15. At this time, the actuator 20 is in the state shown in FIG.

Here, the actuator 20 is provided with a mode switching operation switch (not shown). The mode changeover operation switch (not shown) is also for giving a drive signal to a controller (not shown), and the controller controls the drive of the motor 36 of the actuator 20 according to the mode of the mode changeover switch. This mode switching operation switch has four modes: two-wheel drive, four-wheel high-speed drive, four-wheel neutral and four-wheel low-speed drive.
The controller rotates the motor 36 forward or backward according to the mode of the mode changeover operation switch to rotationally drive the output shaft 23 of the actuator 20 to any one of four predetermined stop positions, and drives the output shaft 23. When the gear 32 reaches a predetermined position, the motor 3
Cut off the power supply to 6. The four stop positions are set within the rotation angle of the drive gear 31 for one rotation.

When the mode changeover operation switch is switched to the four-wheel high-speed drive mode from the two-wheel drive state, the motor 36 is driven to rotate in the normal direction, and the drive gear 32 rotates in the direction of arrow A shown in FIG. The output shaft 23 also rotates in the same direction. The rotation of the rotary plate 24 fixed to the base end 23a of the output shaft 23 causes the rollers 26 and 28 to rotate about the rotation center 24a of the rotary plate 24. As shown in FIG. 11, the rotation of one roller 26 causes one cam 13 to rotate.
The one cam 13 slides upward along the support shaft 19 in FIG. 11 via the cam groove 14. As the cam 13 slides, the two-wheel drive / four-wheel drive switching shaft 11 moves axially by a stroke S1. By the movement of the stroke S1 of the switching shaft 11 for switching between two-wheel drive and four-wheel drive, the state of two-wheel drive is automatically switched to the state of four-wheel high-speed drive (4H).
That is, the rear wheel output shaft gear 5a and the front drive gear 8
Two-wheel / four-wheel switching slider 9 for intermittently engaging and disengaging with a
Thus, both gears 5a and 8a are spline-fitted, and the power of the engine 2 is transmitted not only to the rear wheels 7B and 7B but also to the front wheels 7A and 7A via the front wheel output shaft 8 and the front wheel differential gear 6A. The four wheels are driven at high speed by the rear wheels 7A and 7B. At that time, the power supply to the motor 36 is cut off. still,
The other roller 28 still does not engage with the cam groove 16 of the cam 15 and therefore does not move the four-wheel speed switching shaft 12.

While the two-wheel drive / four-wheel drive switching shaft 11 is axially moved to switch from the two-wheel drive state to the four-wheel high-speed drive state, the rear wheel output shaft gear 5a and the front drive gear are used. The two gears of 8a are out of phase with each other.
When the output shaft 23 of the actuator 20 is stopped because the spline fitting of the two gears 5a and 8a cannot be performed by the four-wheel switching slider 9, the rotation holding plate 31, the drive gear 32, and the compression coil spring 35 disengage from each other, as shown in FIG. The waiting mechanism 30 is operated. That is, even if the output shaft 23 of the actuator 20 and the rotary holder 31 are restrained and stopped, the motor 36 is still energized, so that the drive gear 32 continues to rotate in the direction of arrow A shown in FIG. Therefore, one end 35a of each compression coil spring 35 is prevented from rotating by each spring pressing portion 31b of the rotation holding plate 31 that is stopped, and each compression coil spring 35 is in a compressed waiting state. . At this time, the power supply to the motor 36 is cut off.

When the phases of the rear wheel output shaft gear 5a and the front drive gear 8a coincide, the output shaft 23 is released from the restrained state, and the elastic repulsive force of each compression coil spring 35 in the compressed state causes the output shaft 23 to be released. The output shaft 23 and the rotary plate 24 are normally rotated via the spring pressing portions 31b of the rotary holder 31. As a result, the two-wheel / four-wheel switching slider 9 is spline-engaged with both gears 5a and 8a.
It automatically switches from four-wheel drive to four-wheel high-speed drive.

Further, in this state, the mode selector switch is operated to switch to the two-wheel drive mode, and the output shaft 23 is rotated in the reverse direction to switch from the four-wheel high-speed drive mode to the two-wheel drive mode. Even when the spline fitting between the rear wheel output shaft gear 5a and the front drive gear 8a cannot be released by the four-wheel switching slider 9, as shown in FIG. 15, the other one of the compression coil springs 35 of the waiting mechanism 30 is Since the rotation of the end portion 35b is blocked by the spring pressing portions 31b of the rotation holding plate 31 that is stopped, the compression coil springs 35 are in a compressed waiting state, so that the two-wheel drive state is changed. As in the case of switching to the four-wheel high-speed drive state, when the restrained stop state of the output shaft 23 is released, the four-wheel high-speed drive state is automatically switched to the two-wheel drive state. Rukoto can. Furthermore, not only in the case of switching between these 2H and 4H, but also in the case of 4 described later.
The waiting mechanism 30 operates at all positions between 2H-4H-4L including the case of switching between H and 4L (four-wheel low speed drive).

Further, from the state of the four-wheel high-speed drive shown in FIG. 11, when the mode switching operation switch is operated to switch to the four-wheel neutral mode and the output shaft 23 is further rotated forward, as shown in FIG. Rotating plate 2 fixed to the base end 23a of 23
By the rotation of 4, the other roller 28 engages with the cam groove 16 of the other cam 15, and the other cam 15 slides upward along the support shaft 19 in FIG. As the other cam 15 slides, the four-wheel speed switching shaft 12 moves in the axial direction by a stroke S2.
Just move. Stroke S of this four-wheel speed switching shaft 12
The movement of 2 automatically switches to the 4-wheel neutral (N) state. At this time, the roller 26 is in the cam groove 14 of the cam 13.
Since the engagement is released away from, the two-wheel drive and four-wheel drive switching shaft 11 is not moved.

Then, from the four-wheel neutral state shown in FIG.
When the mode switching operation switch is switched to the four-wheel low speed drive mode and the output shaft 23 is further rotated in the forward direction, the other cam 15 slides further upward along the support shaft 19, as shown in FIG. With the sliding of the other cam 15, the four-wheel speed switching shaft 12 moves axially by a stroke S3. The movement of the stroke S3 of the four-wheel speed switching shaft 12 automatically switches to the four-wheel low speed drive state.

By the selective changeover operation of the mode changeover operation switch, the four-wheel low-speed driving state is changed to the four-wheel neutral state, the four-wheel neutral state is changed to the four-wheel high-speed driving state, or the four-wheel high-speed driving state is changed to the two-wheel driving state. Then, the output shaft 23 is reversely rotated by the reverse rotation of the motor 36, and the output shaft 23 is rotationally driven to a predetermined stop position determined in advance in accordance with the switching mode of the mode switching operation switch. And cam 13
Alternatively, the cam 15 is driven to move the two-wheel drive and four-wheel drive switching shaft 11 or the four-wheel speed switching shaft 12 by a predetermined stroke to switch to the respective states.

Thus, the sliding shaft 1 for switching between the two-wheel drive and the four-wheel drive and the sliding cam 1 for driving the four-wheel speed switching shaft 12 are provided.
3, 15 are attached respectively, and a pair of rollers 26, 28 rotatably supported by a rotary plate 24 fixed to the output shaft 23 of the actuator 20 are respectively attached to the cams 13, 1 respectively.
5 to engage the pair of rollers 26, 28 with the cams 13, 1
5 is a cam follower for driving the cam followers 26, 28 and the cams 13, 1 by driving the actuator 20.
Since the respective switching shafts 11 and 12 can be moved by a predetermined stroke in the axial direction via 5, the four states of two-wheel drive, four-wheel high-speed drive, four-wheel neutral and four-wheel low-speed drive can be automatically and easily performed. Can be switched.

Further, the output shaft 23 is fixed to the tip 23b of the output shaft 23 via a rotation holding plate 31 held so as not to rotate relative to the output shaft 23.
The waiting mechanism 30 can be easily assembled simply by storing the compression coil springs 35 in the respective spring storage portions 33 of the drive gear 32 rotatably supported by
The assembling workability can be improved, the waiting mechanism 30 can be made small, and the number of parts can be reduced. Therefore, the actuator 20 can be made small and inexpensive.

Further, the compression coil springs 35 are housed in the respective spring housing portions 33 provided in a plurality of arcuate shapes at equal intervals on the same circumference of the drive gear 32. The load and stress of the spring 35 can be reduced.

Further, one of the both ends 35a and 35b of each compression coil spring 35 is connected to the other spring storage portion 3 of each compression coil spring 35.
It is possible to bend each compression coil spring 35 by pressing one of them with each spring pressing portion 31b of one rotation holding plate 31 while being held in 3, so that the cost can be further reduced accordingly. You can Further, by storing the compression coil springs 35 in the spring storage portions 33 of the drive gear 32, the compression coil springs 35 function as dampers that absorb impact force when the output shaft 23 is restrained and stopped. Therefore, it is possible to prevent breakage of each component of the actuator 20.

According to the above-described embodiment, the two-wheel drive / four-wheel drive switching device used for the part-time 4WD capable of driving four wheels only when necessary in the two-wheel drive vehicle, and the switching device driving device. Although the actuator has been described, it goes without saying that each of the above embodiments can be applied to a two-wheel drive and four-wheel drive switching device used for 4WD other than part-time 4WD, and an actuator for driving the switching device. It can also be applied to an actuator that drives two driven shafts that are arranged parallel to each other and that are movable in the axial direction.

[0041]

As described above, according to the actuator of the present invention, a drive gear that meshes with a worm and a plurality of drive gears formed on the same circumference and at a predetermined distance in the circumferential direction. Each coil spring housed in each spring housing part and a plurality of spring pressing parts that can press either one of both ends of each coil spring are formed to project, and the rotation is held on the output shaft so that it cannot rotate relative to each other. Since the waiting mechanism is composed of the holding plate and the slits formed between the spring accommodating portions of the drive gear to prevent interference with the spring pressing portions, the waiting mechanism can be easily assembled. The waiting mechanism can be made compact and the number of parts can be reduced, resulting in a compact and inexpensive actuator. It exhibits an excellent effect.

Further, since each coil spring functions as a damper that absorbs an impact force when the output shaft is constrained, it also has an effect of preventing damage to each component constituting the actuator.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of an actuator used in a two-wheel drive and four-wheel drive switching device according to an embodiment of the present invention.

FIG. 2 is a perspective view of the actuator seen from the back side.

FIG. 3 is a plan view showing a part of the actuator in section.

FIG. 4 is a plan view showing a state in which a rotation holding plate of the actuator is removed.

FIG. 5 is an exploded perspective view showing a relationship between a rotation holding plate, a drive gear and an output shaft of the actuator.

FIG. 6 is a bottom view of the rotation holding plate.

FIG. 7 is a perspective view of the output shaft.

FIG. 8 is a bottom view of the output shaft.

FIG. 9 is a schematic configuration diagram of a part-time four-wheel drive vehicle using the two-wheel drive and four-wheel drive switching device.

FIG. 10 is an explanatory diagram showing a two-wheel drive state of the two-wheel drive and four-wheel drive switching device.

FIG. 11 is an explanatory diagram showing a four-wheel high-speed drive state of the two-wheel drive and four-wheel drive switching device.

FIG. 12 is an explanatory diagram showing a four-wheel neutral state of the two-wheel drive and four-wheel drive switching device.

FIG. 13 is an explanatory diagram showing a four-wheel low-speed drive state of the two-wheel drive and four-wheel drive switching device.

FIG. 14 is a plan view showing, in a partial cross section, a waiting mechanism at the time of normal rotation of the actuator.

FIG. 15 is a plan view showing, in a partial cross section, a waiting mechanism at the time of reverse rotation of the actuator.

[Explanation of symbols]

4 transfer 10 two-wheel drive and four-wheel drive switching device 11 two-wheel drive and four-wheel drive switching shaft (driven shaft) 12 four-wheel speed switching shaft (driven shaft) 13, 15 cam 20 actuator 21 first Actuator case 21a Second actuator case 23 Output shafts 26, 28 Rollers (cam followers) 30 Waiting mechanism 31 Rotation holding plate 31b Spring pressing portion 32 Drive gear 33 Spring housing portion 34 Slit 35 Cylindrical compression coil spring (coil spring) 35a , 35b End 36 Motor 37 Armature shaft 38 Worm

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Claims (6)

[Claims] 1. A plurality of driven shafts, which are arranged in parallel with each other and are movable in the axial direction, driving cams for driving the driven shafts respectively attached to the driven shafts, and a plurality of the cams. An actuator in which each driven shaft is selectively moved by a predetermined stroke in the axial direction by driving to a predetermined stop position that is predetermined according to the mode of the operation switch having the changeover mode of The actuator is a motor that rotates normally or reversely when energized, a drive gear that meshes with a worm formed on the armature shaft of the motor, an output shaft that is connected to the drive gear, and a rotation that occurs when the output shaft rotates. A pair of cam followers that engage with the respective cams to drive the respective cams, and at predetermined intervals in the circumferential direction on the same circumference of the drive gear. Each of the coil springs respectively accommodated in the plurality of spring accommodating portions formed, the rotation holding plate held by the output shaft so as not to rotate relative to each other, and both ends of the coil springs protrudingly formed on the rotation holding plate. A plurality of spring pressing portions capable of pressing one of them, slits formed between the spring housing portions of the drive gear for preventing interference with the spring pressing portions, the drive gear and the rotation holding plate And a first actuator case accommodating the output shaft, and a second actuator fixed to the first actuator case, supporting the driven shafts axially movably and accommodating the cams. A case, wherein rotation of the drive gear is transmitted to the output shaft via the coil springs and the rotation holding plate. In both cases, when the output shaft is restrained in the middle and stopped, and the drive gear continues to rotate, one of both ends of each coil spring is pressed by each spring pressing portion of the rotation holding plate. An actuator characterized by. 2. The actuator according to claim 1, wherein the plurality of spring accommodating portions formed in the drive gear are three arc-shaped spring accommodating portions formed at equal intervals in a circumferential direction of the drive gear. In addition, the coil springs are three cylindrical compression coil springs. 3. A two-wheel drive and four-wheel drive switching shaft and a four-wheel speed switching shaft, which are arranged in parallel with each other in the transfer and are movable in the axial direction, and a switching shaft attached to each of these switching shafts. Each of the cams in the two-wheel drive and four-wheel drive switching device provided with a drive cam is driven to a predetermined stop position that is predetermined according to the mode by the switching operation of the mode switching operation switch, By selectively moving each of the switching shafts by a predetermined stroke in the axial direction, 2
4 wheel drive, 4 wheel high speed drive, 4 wheel neutral and 4 wheel low speed drive
In a two-wheel drive and four-wheel drive switching device driving actuator for selectively switching between two driving states, the actuator is formed of a motor that rotates forward or backward by energization and an armature shaft of the motor. A drive gear that meshes with the worm, an output shaft that is connected to the drive gear, a pair of cam followers that are rotated by the rotation of the output shaft and that engage with the cams and drive the cams, and Coil springs respectively housed in a plurality of spring housings formed on the same circumference of the gear and at predetermined intervals in the circumferential direction, and a rotation holding plate held by the output shaft such that they cannot rotate relative to each other. A plurality of spring pressing portions projectingly formed on the rotation holding plate and capable of pressing either one of both end portions of each coil spring; A slit that is formed between the spring accommodating portions to prevent interference with the spring pressing portions, a first actuator case that accommodates the drive gear, the rotation holding plate, and the output shaft, and A second actuator case that is fixed to one actuator case, supports each of the switching shafts so as to be movable in the axial direction, and accommodates each of the cams;
When the rotation of the drive gear is transmitted to the output shaft through the coil springs and the rotation holding plate, the output shaft is stopped midway and stopped, and the drive gear continues to rotate, An actuator for driving a switching device between two-wheel drive and four-wheel drive, wherein either one of both ends of each coil spring is pressed by each spring pressing portion of the rotation holding plate. 4. The two-wheel drive and four-wheel drive switching device driving actuator according to claim 3, wherein the plurality of spring accommodating portions formed in the drive gear are arranged in a circumferential direction of the drive gear. An actuator for driving a switching device for two-wheel drive and four-wheel drive, characterized in that there are three arc-shaped spring accommodating portions formed at intervals and each coil spring is three cylindrical compression coil springs. . 5. A two-wheel drive and four-wheel drive switching shaft and a four-wheel speed switching shaft, which are arranged in the transfer in parallel with each other and are axially movable, and switching shafts respectively attached to these switching shafts. The cams for driving and the mode change operation switches are rotationally driven to predetermined stop positions according to the mode by the switching operation, and each cam is driven to selectively axially move each switching shaft. Having an actuator for moving a predetermined stroke, two-wheel drive,
In a switching device for two-wheel drive and four-wheel drive, which selectively switches between four drive states of four-wheel high-speed drive, four-wheel neutral and four-wheel low-speed drive, the actuator is normally or reversely rotated by energization. A motor, a drive gear that meshes with a worm formed on an armature shaft of the motor, an output shaft connected to the drive gear, and the output shaft that is rotated by the rotation of the output shaft to engage with each of the cams. A pair of cam followers for driving the cams, coil springs respectively housed in a plurality of spring housings formed on the same circumference of the drive gear and at predetermined intervals in the circumferential direction, and the output shaft. And a plurality of spring pressing plates formed on the rotation holding plate so as to be able to press either one of both ends of each of the coil springs. And a slit formed between the spring housing portions of the drive gear to prevent interference with the spring pressing portions, a first housing housing the drive gear, the rotation holding plate, and the output shaft, respectively. An actuator case, and a second actuator case fixed to the first actuator case, supporting the respective switching shafts axially movably and accommodating the respective cams,
When the rotation of the drive gear is transmitted to the output shaft through the coil springs and the rotation holding plate, the output shaft is stopped midway and stopped, and the drive gear continues to rotate, A two-wheel drive / four-wheel drive switching device, wherein each spring pressing portion of the rotation holding plate presses one of both ends of each coil spring. 6. The two-wheel drive and four-wheel drive switching device according to claim 5, wherein the plurality of spring accommodating portions formed in the drive gear are formed at equal intervals in a circumferential direction of the drive gear. The two-wheel drive and four-wheel drive switching device is characterized in that the coil springs are three arc-shaped spring accommodating portions and the coil springs are three cylindrical compression coil springs.