JPH0523966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a backing device for a vehicle having a shift drum type transmission that changes gears by rotating a shift drum.

(Prior Art) Shift drum type transmissions, which are often used in motorcycles, are usually not equipped with a backing device.
A small 3 or 4 engine with such a transmission
BACKGROUND OF THE INVENTION Conventionally, there have been small vehicles mounted on wheeled vehicles for traveling on rough terrain, but in this case a backing device may be required. If this backing device is integrated into the transmission, a problem arises in that the entire engine must be designed separately. Therefore, it is conceivable to interpose a forward/reverse switching mechanism between the transmission without a back gear and the rear wheel transmission, but in this case, after switching between the forward/reverse, the shift drum of the transmission is set to the appropriate gear. Switching requires 2 operations.
It gets to a stage and becomes a hassle.

(Objective of the Invention) The present invention was made in view of the above circumstances, and it makes it possible to use a conventional engine with a forward transmission only without making any major changes to the engine itself, and to make it possible to go backwards as well. An object of the present invention is to provide a vehicle backing device which simplifies driving operations when switching gears.

(Structure of the Invention) According to the present invention, this object is to provide a system between a transmission that changes speed by the rotation of a shift drum and a rear wheel transmission device that transmits the output of the transmission to the rear wheels. A forward/reverse switching mechanism capable of switching forward/reverse switching and transmitting the same to the rear wheel transmission device is interposed, and an interlocking mechanism is provided for rotating the shift drum to a predetermined gear in conjunction with switching of the forward/reverse switching mechanism. This is achieved by a vehicle backing device characterized by the following. The present invention will be explained in detail below based on the illustrated embodiments.

(Example) Fig. 1 is a side view of a four-wheeled vehicle for traveling on rough terrain according to the present invention, Fig. 2 is a power transmission system diagram, Fig. 3 is a side view showing the shaft arrangement of main parts, Figs. 4 and 5 6 and 7 are diagrams showing the operation of the interlocking mechanism during forward movement and backward movement.

In FIG. 1, reference numerals 10 and 12 are front wheels and rear wheels, each of which is equipped with a wide ultra-low pressure tire. An engine 14 is mounted near the center of the vehicle body. A shift drum type transmission 16 is incorporated into this engine 14. The crankshaft 18 of the engine 14 is disposed horizontally as shown in FIG.
are arranged side by side. The rotation of the crankshaft 18 is transmitted to the main shaft 20 via a large reduction gear 24 and a clutch 26, and the rotation of this main shaft 20 is transmitted to a subshaft 22 via a group of transmission gears. In FIG. 4, reference numeral 30 is a shift drum, which rotates intermittently when the shift lever 32 is depressed or kicked up, and is connected to the main shift gear group.
The coupling with the secondary shafts 20 and 22 is changed. That is, a fork (not shown) is moved parallel to the main and subshafts 20 and 22 by a cam groove provided on the outer periphery of the drum 30, and the meshing of the transmission gear group is changed by the fork.

In this embodiment, the countershaft 22 serves as the output shaft of the transmission 16, and the countershaft 22 protrudes to the left side of the vehicle body.

Reference numeral 34 denotes a backing device, which is fixed to the left side of the crankcase. Subshaft 22 as output shaft
extends through the crankcase and into the backing device 34. A rear wheel drive sprocket 36 located between the crankcase and a backing device 34 is rotatably held on the countershaft 22, and a boss of this sprocket 36 extends into the backing device 34. Axle 38 of the rear wheels 12, 12 (first, second
A chain 42 is wound around a driven sprocket 40 fixed to the rear wheel drive sprocket 36 and a rear wheel drive sprocket 36.

A gear 44 is fixed to the boss of the sprocket 36, and a slider 46 is held on the subshaft 22 by a spline connection so as to be slidable in the axial direction. This slider 46 is connected to the secondary shaft 2 by a forward/backward switching mechanism described later.
When the sprocket 36 is slid on the gear 44 and is located on the gear 44 side (solid line position in Figures 4 and 5), the toothed clutch 48 engages the gear 44, rotates the sprocket 36 in the forward direction, and moves away from the gear 44. When the gear 46a of the slider 46 is rotated, the gear 44 and the sprocket 36 are rotated in the reverse direction through the reverse gear groups 50 and 52.

As shown in FIG. 4, the forward/reverse switching mechanism includes a fork shaft 56 that slidably supports a fork 54.
, a cylindrical cam 60 fixed to the switching shaft 58 , and a switching lever 62 fixed to the switching shaft 58 . An engagement pin 64 integrated with the fork 54 engages with a cam groove of a cylindrical cam 60. The switching shaft 58 is given the habit of returning clockwise in FIGS. 1 and 3 by a torsion spring 66, while the cylindrical cam 60 and fork 54 are moved to the forward and reverse positions by daytent mechanisms 68 and 70, respectively. It is becoming locked. A pedal 72 that can be raised and lowered is attached to the switching lever 62, and a spring gives it the habit of returning to the upright position (storage position).

Reference numeral 74 denotes an interlocking mechanism that interlocks this forward/reverse switching mechanism and the shift drum 30, and as shown in FIG. gears 78 each fixed to the switching shaft 58;
80. Gear 78 has two concave teeth 78a, gear 80 has three convex teeth 80a, and gear 80a rotates counterclockwise only when concave teeth 78a of gear 78 are in the neutral position of FIG. It becomes possible to rotate in the direction and engages in the state shown in Figure 7, but
At other positions of the gear 78, the convex teeth 80a of the gear 80 come into contact with the circumferential surface of the gear 78, and the gear 80, that is, the switching shaft 58, cannot rotate counterclockwise.

Next, the operation of this embodiment will be explained. During forward movement, the switching shaft 58 returns clockwise in FIGS. 1 and 3, and the slider 46 engages the gear 44 by the clutch 48. At this time, the gear 80 fixed to the switching shaft 58
is in the position shown in FIG. 6, and the rotation of the gear 78 of the connecting rod 76 connected to the shift drum 30 is not restricted by the gear 80. Therefore, by operating the shift lever 32, the shift drum 30 can be rotated to change gears.

When switching to reverse, the shift drum 30 is placed in the neutral position. At this time, the gear 78 fixed to the connecting rod 76 is in the state shown in FIG. If you push the pedal of the switching lever 62 toward the side of the vehicle body with your left foot and step on it, the gear 80 will engage with the gear 78 and the gear 78 and the connecting rod 7 will move.
6. Rotate the shift drum 30 counterclockwise as shown in FIGS.
Retained by 0. Therefore, the transmission 16 is switched to a predetermined lower speed, for example, the first speed, and the cylindrical cam 60 moves the fork 54 and the slider 46 toward the outside of the vehicle body. Therefore, the secondary shaft 2 which is the output shaft
The rotation of No. 2 is transmitted to the gear 44 via the reverse gear group 50, 52, and the sprocket 36 is reversely rotated.

When switching from reverse to forward again, the shift drum 30, connecting rod 76,
The gear 78 may be rotated counterclockwise in FIG. 7 to return the transmission 16 to the neutral position. This action causes
The switching shaft 58 is forcibly rotated clockwise in FIG. 7, and the cylindrical cam 60 and fork 54 are once removed from the detent mechanisms 68 and 70, respectively, and are held at the forward position again.

In Figure 1, 82 and 84 are the front and rear fenders, 8
6 is a fuel tank, 88 is a straddle type driver seat, 90
is the steering wheel.

In this embodiment, the interlocking mechanism 7 is
4, and switching to reverse is possible only when the transmission 16 is in the neutral position, improving safety. Furthermore, when returning to the forward direction, the slider 46 automatically moves from the reverse position to the forward position simply by operating the shift lever 32, so that the return operation to the forward direction can be performed easily and quickly.

Furthermore, the small vehicle of the present invention also includes a motorcycle with a side car.

(Effects of the Invention) As described above, the present invention links the forward/reverse switching mechanism that switches the slider to the reverse position with the shift drum, so that when the slider is moved to the reverse position, the transmission is simultaneously switched to a predetermined gear on the low speed side. With this configuration, the reverse switching operation only needs to be performed once, which simplifies the operation.

[Brief explanation of the drawing]

Fig. 1 is a side view of a four-wheeled vehicle according to the present invention, Fig. 2 is a power transmission system diagram thereof, Fig. 3 is a side view showing the shaft arrangement of the main parts, and Figs. 4 and 5 are the - lines and -. The line sectional view and FIGS. 6 and 7 are diagrams showing the operation of the interlocking mechanism. 10...Front wheel, 12...Rear wheel, 16...Transmission, 22...Subshaft as output shaft, 30...Shift drum, 36...Sprocket, 46...Slider, 50, 52...For reverse movement Gear group, 74...interlocking mechanism.

Claims (1)

[Scope of Claims] 1. Between a transmission that changes speed by rotation of a shift drum and a rear wheel transmission device that transmits the output of the transmission to the rear wheels, the rotational output of the transmission is switched between forward and reverse rotation. A vehicle is provided with a forward/reverse switching mechanism that can be transmitted to a rear wheel transmission, and an interlocking mechanism that rotates the shift drum to a predetermined gear in conjunction with switching of the forward/reverse switching mechanism. Back device. 2. The vehicle backing device according to claim 1, wherein the interlocking mechanism rotates the shift drum from a neutral position to a predetermined low speed gear in conjunction with switching the forward/reverse switching mechanism to the reverse position. 3. The vehicle backing device according to claim 1, wherein the interlocking mechanism rotates the shift drum from a predetermined low speed gear to a neutral position in conjunction with switching the forward/reverse switching mechanism to the forward position.