JPH056445Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a drive shift unit for a two-speed axle for an automobile.

(Prior Art) A differential gear device for an automobile, that is, a two-speed axle, including a high/low two-speed switching mechanism is conventionally known. The two-speed axle transmits power from the propeller shaft to the axle shaft at high and low speeds by switching the meshing gear in the axle housing to the high speed side or the low speed side using the shift fork of the drive shift unit. I can do it. FIG. 4 shows an example of the structure of a conventional drive shift unit, in which first and second swing arms 1, which are vertically spaced apart,
3 are provided rotatably around the shaft 5, and a torsion spring 7 is provided between the first and second swing arms 1 and 3 to apply a pre-tightening force around the shaft 5. A pin 9 protruding from the lower surface of the movable arm 1 and a pin 11 protruding from the upper surface of the second swing arm 3 are sandwiched between both ends of the torsion spring 7 to which a pre-tightening force is applied. A yoke 13 formed at one end of the swinging arm 1 is engaged with a pin 17 formed protrudingly on a ball screw 15 (inside of which many balls are arranged), and the ball screw 15 is rotated forward and backward. A pair of switches 23, 23' are provided in the movement path of the ball screw 15, which are screwed onto a screw shaft 21 connected to the output shaft of the motor 19, and which are turned on and off by the ball screw. A connecting portion 25 to the shift lever is provided at one end of the second swing arm 3. To switch the shift lever between the low and high speed drive positions, the motor 19 is rotated forward and reverse to stop the ball screw 15 in a position where it engages the switch 23 or 23', thereby causing the first swing arm to 1 and the second swing arm 3 which is elastically connected to the first swing arm via a torsion spring 7, respectively, swing as shown by the arrows in the figure.
The shift lever connected to the swing arm of the motor is moved between low and high speed drive positions.

(Problems to be solved by the invention) However, the conventional drive shift unit described above requires an expensive ball screw and a reversing circuit for the motor, making the entire device extremely expensive. .

(Means for Solving the Problems) The present invention has been made to eliminate the above-mentioned conventional drawbacks, and for this reason, the drive shift unit according to the present invention is a drive shift unit for a two-speed axle for an automobile. A first swinging arm capable of swinging between low and high-speed drive positions is drivingly connected to a worm wheel rotationally driven by a one-way drive motor via a rotational swinging mechanism comprising an eccentric pin and a slot. A second swing arm is provided to be coaxially rotatable with the first swing arm, and the second swing arm is rotatable coaxially with the first swing arm.
and a second swinging arm is sandwiched between the ends of a torsion spring to which a pretightening force is applied, a shift lever is connected to the second swinging arm, and the motor is connected to the lower end of the first swinging arm. It is characterized by including a motor drive circuit that stops at the Γ high-speed drive position.

(Function) A worm wheel is rotatably driven in only one direction by a motor, and a first swing arm is connected to the worm wheel via a rotation swing mechanism consisting of an eccentric pin and a slot; A second swing arm, which is elastically connected to the second swing arm via a torsion spring, swings between a high speed drive position and a low speed drive position. By stopping the motor drive to stop the first swing arm at the high speed drive position or the low speed drive position, the shift lever connected to the second swing arm can be shifted between the high and low speed drive positions. .

The worm and worm wheel that transmit the motor driving force to the first swing arm are relatively inexpensive;
Furthermore, since the motor is driven to rotate only in one direction, an inexpensive unidirectional motor with a structure using permanent magnets can be used.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 to 3 show a preferred embodiment of the present invention, in which a unidirectional motor 33 of a type using a permanent magnet is fixed to one side of a shift unit housing 31. , a worm gear 35 is provided on the output shaft protruding into the housing of the motor,
A worm wheel 39 supported horizontally on an intermediate bracket 37 of the housing 31 is connected to the worm gear 3.
It is meshed with 5. An eccentric pin 41 is provided on the worm wheel 39 and is engaged in a slot 47 of a first swinging arm 45 rotatable about a vertical axis 43 pivoted by the housing 31. ing. A torsion spring 49 is provided around the vertical axis 43, and the second swinging arm 51 rotates around the vertical axis 43 with the torsion spring in between so that it can rotate coaxially with the first swinging arm 45. It is possible.
A pre-tightening force is applied to the torsion spring 49, and the rising part 45a of the first swing arm 45 and the falling part 51a of the second swing arm 51 apply the pre-tightening force to the torsion spring. Both ends of 49
It is held between 9a and 49b. Therefore,
The first swing arm 45 and the second swing arm 51 are elastically connected via a torsion spring 49. A connector 55 that engages with one end of a gear shift lever 53 of a two-speed axle is pivotally supported 57 at one end of the second swing arm 51 .
A pair of limit switches 59 and 59' are supported on a bracket 61 below the worm wheel 39 and are arranged 180 degrees opposite each other. The limit switches 59, 59' work together with a switch operating means (for example, a recess or protrusion) formed on the back surface of the worm wheel 39 to stop the drive of the motor 33 every time the worm wheel 39 rotates 180 degrees. The rotation (not shown) is controlled on and off, thereby stopping the first swing arm 45 at the solid line position and the dotted line position in FIG.

To shift the shift lever 53 between the low speed drive position L and the high speed drive position H, the shift switch of the motor drive circuit is set to the low speed side or the high speed side, thereby closing the drive circuit of the motor 33 and starting the motor drive. The force is transferred to the worm gear 35, worm wheel 39, eccentric pin 41 and slot 4.
It is transmitted to the first swing arm 45 via a rotation swing mechanism consisting of 7. The first swing arm 45 is moved to the solid line position or dotted line position in FIG. 1 according to the set drive position, and at that point the limit switch 59 on the side corresponding to the set drive position is moved.
Alternatively, 59' is activated by the switch operating means on the back side of the worm wheel 39 to open the motor drive circuit and stop the swinging of the first swinging arm (note that the limit switch on the side corresponding to the drive position that is not set at this time is closed, and setting the shift switch closes the motor drive circuit). Even if the first swing arm 45 is shifted in this way, the second swing arm 51 cannot immediately follow the shift of the first swing arm due to the meshing resistance of the gear in the axle housing. Torsion spring 4
9, in addition to the pre-tightening force, an increased amount of tightening due to the shift of the first swing arm is superimposed. When the meshing resistance of the gears in the axle housing decreases, the second swing arm 51 follows the shift of the first swing arm 45 and the shift lever 53 is shifted, and at the same time the first and second swing arms shift. The relative positional relationship between 45 and 51 returns to the state before being shifted. In this way, by shifting the first swing arm 45 and the second swing arm 51 between the solid line position and the dotted line position in FIG. 1, the shift lever 53 is shifted between the low Γ high speed drive positions. be able to.

Note that when the slot 47 of the first swing arm 45 is made straight, the worm wheel 39 rotates in one direction, resulting in the maximum swing when the first swing arm swings from the low speed drive position to the high speed drive position. This is not desirable because the angle and the maximum swing angle when swinging from the high speed drive position to the low speed drive position are different. Therefore, as shown in FIG. 1, it is preferable to provide arcuate reliefs 47a on both sides of the slot 47, which are equal to the radius of the rotation locus of the pin 41, so that the two maximum swing angles are equalized.

(Effects of the invention) As described above, according to the invention, a relatively simple and inexpensive one-way motor is used as a drive motor to switch the meshing gear of a two-speed automobile axle between low and high-speed drive positions. can,
In addition, a relatively inexpensive worm gear and worm wheel can be used in place of the conventional expensive ball screw to transmit power from the motor to the first swing arm, significantly reducing the manufacturing cost of the entire device. can be done.

[Brief explanation of the drawing]

Fig. 1 is a plan view partially showing an embodiment of the drive shift unit of the present invention, Fig. 2 is a front view showing the same partially sectional, Fig. 3 is a side view showing the same partially sectional. The figure is a plan view of a conventional drive shift unit. 33...Motor, 35...Worm gear, 39
...Worm wheel, 41...Pin, 45...
First swing arm, 47...Slot, 47a...
...Escape, 49...Torsion spring, 49
a, 49b... end, 51... second swing arm, 53... shift lever.

Claims (1)

[Claims for Utility Model Registration] (1) A drive shift unit for a two-speed axle for an automobile, in which a worm wheel rotationally driven by a unidirectional drive motor is provided with a rotating swing mechanism consisting of an eccentric pin and a slot. a first swinging arm capable of swinging between low and high-speed drive positions; a second swinging arm rotatable coaxially with the first swinging arm;
and a second swinging arm is sandwiched between the ends of a torsion spring to which a pretightening force is applied;
A drive shift unit including a motor drive circuit that connects a shift lever to a first swing arm and stops each of the motors at a low Γ high speed drive position of the first swing arm. (2) the eccentric pin is fixed to the worm wheel, and the slot is formed in the first swinging arm, and the first swinging arm has a maximum swing from a low-speed drive position to a high-speed drive position; The drive shift unit according to claim 1, wherein an arcuate relief is provided on the side surface of the slot so that the angle and the maximum swing angle from the high speed drive position to the low speed drive position are equal.