JP2815854B2 - Vehicle forward / reverse switching limiter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle forward / reverse switching limiting device that limits forward / reverse switching operation at a predetermined vehicle speed or higher. (Background of the Invention) In a three- or four-wheeled vehicle or a motorcycle with a side wheel and provided with a forward / reverse switching device, the vehicle is switched to reverse while the traveling speed is not sufficiently reduced during forward traveling. Doing so may damage the engine and drive train. Also, when the vehicle suddenly switches to the forward direction while the vehicle body is moving in the reverse direction while traveling backward, the engine and the driving system are also damaged. Therefore, it is desirable that the forward / reverse switching be performed after the vehicle speed becomes sufficiently low. (Object of the Invention) The present invention has been made in view of such circumstances,
When the traveling speed is not lower than the predetermined traveling speed, the switching in both directions from forward to reverse, and from reverse to forward can be limited to prevent damage to the engine and the drive system due to sudden switching, and the configuration can be improved. It is an object of the present invention to provide a vehicle forward / backward switching control device that can be relatively simplified. (Constitution of the Invention) According to the present invention, this object is achieved by rotating an output shaft projecting from an engine in a vehicle width direction through a forward / reverse switching device interposed between the output shaft and a propeller shaft orthogonal to the output shaft. A forward / backward bevel gear fixed to the output shaft; a forward / reverse driven bevel gear held to be freely rotatable on the propeller shaft; A slider spline-coupled to the propeller shaft between the driven bevel gears and selectively engaged with one of the driven bevel gears, and a slider slidable in the length direction disposed parallel to the propeller shaft. A shift shaft, a shift fork fixed to the shift shaft for moving the slider, a switching drive mechanism for sliding the shift shaft, and two annular grooves formed at a fixed distance from each other on the shift shaft. A ball selectively resiliently contacting the annular groove so as to hold the shift shaft at a position where the slider engages with both driven bevel gears, and a moderate resistance in an outer peripheral groove of any of the driven bevel gears. And a ring which is dragged by the rotational speed difference between the driven side bevel gear and urged in the rotational direction, and a ring which is urged by the ring in a direction to be engaged in one annular groove of the shift shaft. The present invention is attained by a forward / reverse switching restricting device for a vehicle, comprising: a stopper; (Embodiment) FIG. 1 is a side view of an all-terrain vehicle equipped with an engine according to an embodiment of the present invention, FIG. 2 is a plan sectional view showing a part thereof, and FIG. FIG. 4 is a sectional view taken along line IV-IV and FIG. 3 is a sectional view taken along line VV in FIG. In FIG. 1, reference numeral 10 denotes a body frame, 12 denotes a pair of left and right steering front wheels, 14 denotes a pair of left and right driving rear wheels, and the front wheels 12 and the rear wheels 14 include wide ultra-low pressure tires (so-called balloon tires). It is installed. Rear wheel 14 is a rear arm
It is held by the vehicle body frame 10 via a back tube 16 and a back tube 18. That is, the rear axle is located at the rear end of the rear arm 16.
The rear wheels 14 are fixed to both ends of the rear wheel shaft 20, respectively. Reference numeral 200 denotes an engine mounted near the center of the vehicle body, 26 denotes a front fender, 28 denotes a rear fender, 30 denotes a steering bar handle, and 32 denotes a straddle-type operation seat disposed at an upper part of the vehicle body. Reference numeral 74 denotes a foot-operated shift pedal, which changes the speed of a known drum-type speed change mechanism. As shown in FIG. 2, the engine 200 includes a crankshaft 202 , a clutch 204, a speed change main shaft 210 arranged in parallel with the crankshaft 202 , and a main shaft 206
And a transmission gear group 208 attached to the transmission countershaft 206 and the countershaft 210. The speed change sub shaft 210 also serves as an output shaft. The rotation of the crankshaft 202 is controlled by the clutch 204 and the speed change spindle 20.
6, transmitted to the transmission countershaft 210 via the transmission gear group 208. Two
Reference numeral 12 denotes a propeller shaft extending in the front-rear direction of the vehicle body. On the propeller shaft 212, a driven-side forward bevel gear 214 and a driven-side reverse bevel gear 216 are rotatably held.
Reference numeral 16 meshes from both sides with a drive-side bevel gear 218 fixed to the transmission countershaft 210. Both bevel gears 214 and 216 on the propeller shaft 212
A slider 220 which is interposed and spline-coupled so as to slide only in the axial direction is provided, and the slider 220 and the bevel gears 214 and 216 respectively form a dog clutch. Reference numeral 222 denotes a shift shaft, which is held by the cover 224 so as to be slidable in the front-rear direction.
26 has been fixed. The shift fork 226 is engaged with the slider 220. Rack 228 on shift shaft 222
On the other hand, a pinion 232 that engages with the rack 228 is fixed to the operation shaft 230 penetrating the cover 224, and the shift shaft 222 and the shift fork are rotated by rotating the operation shaft 230 from outside the cover 224. 226 is moved, and forward / reverse switching is performed. That is, as shown in FIGS.
If 22 is to the left, the slider 220 engages the forward bevel gear 214, and the propeller shaft 212 rotates the rear wheel shaft 20 in the forward direction via the final reduction gear 234 (FIG. 2). When the operating shaft 230 is rotated counterclockwise in FIG. 3, the shift shaft 222 moves rightward in FIGS. 2 and 3, the slider 220 engages with the reverse bevel gear 216, and the vehicle moves backward. I do. The operation shaft 230 protrudes from the cover 224 as shown in FIG. 4, and a lever 236 is fixed to this protruding end. This lever 236 is linked with the switching lever 237 shown in FIG. That is, the switching lever 237 is attached to the engine 200 so as to swing back and forth on the left crankcase, and the movement of the switching lever 237 is transmitted to the lever 236 via the wire 237a. When the switching lever 237 is tilted forward to the F position, the operating shaft 230 rotates clockwise in FIG. 3, and the slider 220 is engaged with the forward bevel gear 214. Similarly, switching lever 237
Is moved backward to the R position, the slider 220 is engaged with the bevel gear 216 for backward movement. Thus, lever 236, wire 237a,
The switching lever 237 forms a switching drive mechanism. In FIGS. 4 and 5, 238 is a cam fixed to the operation shaft 230, 240
Are cam followers which resiliently contact the 238, and these form a click mechanism which stops on the operation shaft 230 between the forward position and the reverse position. The shift shaft 222 has two annular grooves 242, 2
44 is formed, while one groove has a ball 246 (third groove).
(FIG. 2), which form a click mechanism that stops the fork shaft 222 in the forward and reverse positions. Next, the forward / reverse switching limiting device 248 will be described. 250 covers
A support shaft parallel to the shift shaft 222 fixed to 224, a stopper 252 slidably held by the support shaft 252, and a return means 254 for urging the stopper 252 in a direction away from the shift shaft 222. As a coil spring. This coil spring
One end of 254 is locked to a pin 256 protruding from the support shaft 250. Reference numeral 258 denotes a ring which is engaged with an annular groove formed on the outer periphery of the forward bevel gear 214 with an appropriate resistance.
One end of the ring 258 is connected to a stopper 252 as shown in FIG.
In the direction of pressing the shift shaft 222. Therefore, when the slider 220 is moved forward with engagement with the forward bevel gear 214, the propeller shaft 212 rotates clockwise in FIG.
The ring 258 is urged in the same direction to press the stopper 252 counterclockwise. The vehicle speed is high enough and the ring 258 is the stopper 252
When the urging force for pressing is larger than the restoring force of the coil spring 254 as the restoring means, the stopper 252 rotates in the same direction and engages with the annular groove 244 of the shift shaft 222. Therefore, at this time, the movement of the shift shaft 222 is restricted, and it is impossible to switch to reverse. Coil spring 254 if vehicle speed is low enough
Return force is greater than the urging force of the ring 258, and the stopper 2
52 is returned and can be switched to reverse. Also, during reverse traveling, the slider 220 is engaged with the reverse bevel gear 216, but at this time, the rotation direction of the forward bevel gear 214 does not change, so that the vehicle speed is sufficiently high and the ring 258 pushes the stopper 252. Coil spring 2 as urging force return means
If the return force is larger than 54, the stopper 252 rotates in the same direction and engages with the annular groove 222 of the cyst shaft 222. Therefore, at this time, switching from reverse to the above is limited. As described above, the ring 258, the stopper 252, and the like can regulate both switching from forward movement to reverse movement and vice versa. (Effect of the Invention) As described above, the present invention provides a stopper that engages with and disengages from the annular groove for the click mechanism provided on the shift shaft, and urges the stopper by the return means in a direction to escape from the annular groove.
A ring that engages with an appropriate resistance in the outer peripheral groove of the driven or driven bevel gear on the propeller shaft is provided, and the stopper is annularly formed by this ring and the urging force generated by the rotational speed difference with the bevel gear. Since it is designed to engage the groove, it is not possible to switch between forward and backward at a predetermined speed or higher. That is, the switching from forward to reverse and the switching in the reverse direction can be restricted by one stopper, return means, and the like. Therefore, it is possible to prevent damage to the engine and the driving system due to sudden switching between forward and backward running. In addition, since the annular groove used for the click mechanism of the shift shaft is used, the mechanism inside the crankcase of the engine only needs to be changed in the case housing the front and rear bevel gears without making any changes. Is relatively simple.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of an all-terrain four-wheeled vehicle equipped with an engine according to one embodiment of the present invention, FIG. Is a sectional view taken along the line III-III, and FIGS. 4 and 5 are a sectional view taken along the line IV-IV and a line VV in FIG. 200 … Engine, 202 … Crank shaft, 210… Variable speed auxiliary shaft as output shaft, 212… Propeller shaft, 214… Forward driven bevel gear, 216… Reverse driven bevel gear, 252 … Stopper, 258 … Ring, 258 … Spring as return means.

Claims (1)

(57) [Claims] In a vehicle forward / reverse switching limiting device that transmits rotation of an output shaft projecting from an engine in a vehicle body width direction to a rear wheel via a forward / reverse switching device interposed between the output shaft and a propeller shaft orthogonal to the output shaft, A drive-side bevel gear fixed to the output shaft; a forward and a reverse driven bevel gear rotatably held by the propeller shaft; and a spline connection between the two driven bevel gears to the propeller shaft. A slider selectively engaged with one of the driven bevel gears, a shift shaft disposed parallel to the propeller shaft and slidable in the length direction thereof, and the slider fixed to the shift shaft to move the slider. A shift fork, a switching drive mechanism for sliding the shift shaft, two annular grooves formed on the shift shaft at a fixed distance from each other, and the slider engaging with the driven bevel gears. And the rotational speed of the ball selectively engaged with the annular groove so as to hold the shift shaft at a position, and the outer peripheral groove of any one of the driven bevel gears is engaged with an appropriate resistance. A ring which is pulled by the difference and is urged in this rotational direction, a stopper which is urged by the ring in a direction engaging with one annular groove of the shift shaft, and a direction in which the stopper comes out of the annular groove And a return means for urging the vehicle forward and backward.