JPS60107422A - Retreat apparatus for car - Google Patents

Abstract

PURPOSE:To constitute a motor-cycle which can advance and retreat by permitting retreat by utilizing an engine equipped with a speed change gear for advance use only without markedly changing the engine itself. CONSTITUTION:An advance/retreat switching apparatus is equipped with a fork shaft 56 for supporting a fork 54 in slidable ways, cylindrical cam 60 fixed onto a switching shaft 58, and a switching lever 62 fixed onto the switching shaft 58. The switching shaft 58 is provided with the clockwise turning recovery characteristic by a torsion spring 66. The cylindrical cam 60 and the fork 54 are engaged at the advance and retreat positions by the detent mechanisms 68 and 70 respectively. In retreat operation, a shift drum 30 is turned counterclockwise through gears 78 and 80 when the switching lever 62 is stepped-in, and then a speed change gear is switched to low-speed side. At the same time, the revolution of a subshaft 22 as output shaft is transmitted to the gear through the gear group 50 and 52 for retreat, and a sprocket 36 is revolved reversely.

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 not usually provided with a reversing device.

There have conventionally been small three- or four-wheeled vehicles equipped with a transmission-equipped engine such as Kono for traveling on rough terrain, but in this case, a backup device may be required. When this backing device is integrated into the transmission, a problem arises in that the entire engine must be provided separately.

Therefore, it is conceivable to interpose a forward/reverse switching mechanism between the transmission without a backing device and the rear wheel transmission, but in this case, after performing the forward/reverse switching, the shift drum of the transmission is set to the appropriate gear. Switching would require two steps of operation, which would be cumbersome.

(Purpose of the Invention) The present invention was made in view of the above circumstances, and it is possible to use a conventional engine with a forward transmission only and make it possible to move in reverse without making any major changes to the engine itself. An object of the present invention is to provide a reversing device for a vehicle that simplifies driving operations when switching between forward and reverse directions.

(Structure of the Invention) In order to achieve this object, the present invention interposes a forward/reverse switching mechanism between a transmission that changes speed by rotation of a shift drum and a rear wheel transmission device that transmits the output of this transmission to the rear wheels. On the other hand, an interlocking mechanism is provided which rotates the shift drum to a predetermined stage in conjunction with switching of the forward/reverse switching mechanism.

The present invention will be described 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;
The figure is a power transmission system diagram, Figure 3 is a side view showing the shaft arrangement of the main parts, Figures 4 and 5 are cross-sectional views along the ■-■ line and ■-v line,
FIGS. 6 and 7 are diagrams showing the operation of the interlocking mechanism during forward movement and backward movement.

In FIG. 1, reference numerals 10.12 are front wheels and rear wheels, each of which is equipped with wide ultra-low pressure tires. 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 arranged in a horizontal direction as shown in FIG. 2, and the main shaft 20 of the transmission 16 is located behind it. Subshafts 22 are arranged in parallel. The rotation of the crankshaft 18 is controlled by a large reduction gear 24. is transmitted to the main shaft 20 via the clutch 26,
This rotation of the main shaft 20 is transmitted to the sub-shaft 22 via a gear group. In FIG. 4, reference numeral 30 denotes a shift drum, which rotates intermittently when the shift lever 32 is depressed or kicked up to change the connection between the speed change gear group and the main and subshafts 20 and 22. That is, a fork (not shown) is moved parallel to the main and subshafts 20, 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 this 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 back device, which is fixed to the left side of the crankcase. A subshaft 22 serving as an output shaft passes through the crankcase and extends into the back device 34. A rear wheel drive sprocket 36 located between the crankcase and the back device 34 is rotatably held on the subshaft 22, and a boss of this sprocket 36 extends into the back device 34. Axle 38 of said rear wheel 12.12 (No. 1.2
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 7
A slider 46 is held on the il shaft 22 by spline connection so as to be slidable in the axial direction. This slider 46 is slid on the subshaft 22 by the forward/backward switching mechanism described later, and when it is located on the gear 44 side (solid line position in Fig. 4-5), the gear 46
4 by the dog clutch 48 and the sprocket 36
rotates forward in the forward direction and leaves the gear 44 (4th and 5th
At the imaginary line position in the figure, the rotation of the gear 46a of the slider 46 is transmitted through the reverse gear group 50, 52 and the gear 44. Reverse sprocket 36.

The forward/reverse switching mechanism includes a fork shaft 56 that slidably supports a fork 54, as shown in FIG.

A cylindrical cam 60 fixed to the switching shaft 58 and the switching shaft 5
8 and a switching lever 62 fixed to the switch lever 62.

An engagement pin 64 integrated with the fork 54 engages with a cam groove of a cylindrical cam 60. A torsion spring 6 is attached to the switching shaft 58.
6 gives a clockwise rotational return habit in FIGS. 1 and 3, while the two cylindrical cams 60 and fork 54 move forward.
They are respectively locked in the reverse position by detent mechanisms 68 and 70. A pedal 72 that can be activated is attached to the switching lever 62, and is moved to the upright position (
It has a habit of returning to the storage position).

74 is an interlocking mechanism that interlocks this forward/reverse switching mechanism and the shift drum 30, and as shown in FIG. and gears 78 and 80 respectively fixed to the switching shaft 58. The gear 78 has two incisors 78a, and the gear 80 has three convex teeth 80a, and the convex teeth 80a of the gear 80 move counterclockwise only when the incisors 78a of the gear 78 are in the neutral position of FIG. It becomes possible to rotate and mesh as shown in Fig. 7.

At other positions of the gear 78, there are convex teeth 80 of the gear 80 on its circumferential surface.
a comes into contact with the gear 80, that is, the switching shaft 58 cannot rotate counterclockwise.

Next, the operation of this embodiment will be explained. When moving forward, the switching shaft 58
returns clockwise in FIGS. 1 and 3, and the slider 46 is engaged with 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. When the pedal of the switching lever 62 is pushed down toward the side of the vehicle body with the left foot, the gear 80 engages with the gear 78 and the gear 78. Connecting rod 76° The shift drum 30 is rotated counterclockwise as shown in FIGS. 1 and 3, and in this state the detent mechanism 6
8.70. Therefore, the transmission 16 switches to a predetermined low speed gear 1, for example, the first gear, and the cylindrical cam 6° moves the fork 54 and the slider 46 toward the outside of the vehicle body. Therefore, the rotation of the countershaft 22, which is the output shaft, is transmitted to the gear 44 via the reverse gear group 50, 52, and the sprocket 36 is rotated in the reverse direction.

When switching from reverse to forward again, the shift drum 30. Connecting rod 76° gear 78
The transmission 16 may be returned to the neutral position by rotating it counterclockwise in the figure. Due to this behavior.

The switching shaft 58 is forcibly rotated clockwise in FIG. 7, and the cylindrical cam 60. Each fork 54 has a detent mechanism 68
．． 70 and is held again in the forward position.

In Fig. 1, 82 and 84 are front and rear fenders, 86 is a fuel tank, 88 is a straddle type driving seat), and 90 is a steering handle.

In this embodiment, the interlocking mechanism 74 is composed of gears 78 and 80, and switching to reverse is possible only when the transmission 16 is in the neutral position, improving safety.

Further, when returning to the forward direction, the slider 46 is automatically moved from the reverse position to the forward position by simply 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, and simultaneously switches the transmission to a predetermined gear on the low speed side when moving the slider to the reverse position. Since it is configured so that the reverse gear can be switched, the reverse switching operation only needs to be done once, which simplifies the operation.

[Brief explanation of drawings]

Fig. 1 is a side view of the four-wheeled vehicle according to the present invention, Fig. 2 is its power transmission system diagram, Fig. 3 is a side view showing the shaft arrangement of the main parts, and Fig. 4.5 is its TV-TV line. 6.7 is a sectional view taken along the line V-V, and FIG. 6.7 is a diagram 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...Reverse gear group. 74... Interlocking mechanism. Patent applicant Yamaha Motor Co., Ltd. Agent Patent attorney Yama 1) Yu Moon

Claims (3)

[Claims] (1) A transmission that changes speed by rotating a shift drum. A forward/reverse switching mechanism is interposed between the rear wheel transmission device that transmits the output of the transmission to the rear wheels, and an interlocking mechanism that rotates the shift drum to a predetermined gear in conjunction with switching of the forward/reverse switching mechanism. A vehicle backing device characterized by being provided with. (2) The vehicle reversing 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 reversing 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.