JPS58136580A - Car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle that transmits engine output to rear wheels using a constant mesh transmission and a shaft drive mechanism.

2. Description of the Related Art Conventionally, there is a vehicle such as a motorcycle that transmits the output of an engine to a rear wheel via a constant mesh transmission and a shaft drive mechanism.

In this case, the constant-mesh type transmission uses a dog clutch to connect and connect the transmission gear group, which is constantly rotating during operation, and the main shaft and subshaft that hold these gear groups, resulting in a large impact during gear shifting. For this reason, especially in the case of a vehicle in which engine output is transmitted to the rear wheels by a shaft drive mechanism, it is necessary to provide a shock absorber in the power transmission mechanism in order to alleviate the impact during gear shifting. In other words, in systems where engine output is transmitted to the rear wheels through a chain mechanism, this shock can be absorbed by the loosening of the chain, but when a shaft drive mechanism is adopted, power is transmitted only through gears. This is because it is not possible to provide play in the gears.

As the shock absorbing device, a structure in which two cylinders each having a cam formed on the end surface are pressed by a spring so that the cams come into contact with each other has been widely used. However, there are problems in that a shock absorbing device designed to sufficiently absorb the impact is large in size, considerably heavy in weight, and has a complicated structure.

This invention was made in view of these circumstances,
It is an object of the present invention to provide a vehicle which can reduce the size and weight of a shock absorbing device for absorbing shock during gear shifting of the constant mesh transmission, and furthermore, can eliminate the need for this shock absorbing device in some cases.

In order to achieve such an object, the present invention provides a vehicle in which engine output is transmitted to drive wheels via a constant mesh transmission and a shaft drive mechanism, in which the drive wheels are equipped with ultra-low pressure tires. It is. The present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a side view of an embodiment in which the present invention is applied to a tricycle;
Figure 2 is a partially omitted plan view, Figure 3 is a side view of the main parts,
FIG. 4 is also a plan view of the main parts. In Fig. 1.2, the reference numeral 10 is the vehicle body frame, which includes a steering head pipe 12, a main pipe 14, a pair of left and right down tubes 16 (16a, 16b), and a seat pillar tube 18 (18a, 18b). , C) 7--20
(20a.

20b) and a backstay 22 (22a, 22b). The rear end of the down tube 16 and the lower ends of the seat pillar tube 18 and back stay 22 are respectively connected to a pair of left and right bearings 24 (24a).

24b). These bearings 24a, 24
It is pivoted to be able to swing up and down by b26.

Reference numeral 28 denotes an engine, which is mounted in a space surrounded by the main pipe 14, down tube 16, and seat tilter tube 18. Inside the crankcase of this engine 28 is a constant mesh transmission 3 as shown in FIG.
0 is included. A main shaft 32 of the transmission 30 is rotated by a crankshaft via a clutch built into the engine 28, and the rotation of the main shaft 32 is transmitted to a subshaft 34 via a speed change gear. Note that the main shaft 32 and sub shaft 34
The gears are always in mesh with each other, and these gears are constantly rotating while the engine is running. Sleeves that slide in the axial direction are provided on the main and countershafts 32 and 34, and the sleeves and the side surfaces of the gear form a dog clutch, and speed changes are performed by engaging and engaging the dog clutch.

In Fig. 1, 36 is a front fork, 38 is a front wheel equipped with ultra-low pressure tires, and 40 is a steering wheel.

42 is a rear arm. This rear arm 42 is the second
As shown in FIG. 4, it is formed into a substantially rectangular shape by four knobs, and its front side 42a is connected to the pair of bearings 24a, 2.
4b by a pivot shaft 26, and the rear side 4
An axle 44 is rotatably held at 2b. At both ends of this axle 44 are rear wheels 46 as a pair of left and right driving wheels.
(46a, 46b) are fixed. As shown in FIG. 2, the rear wheel 46 is composed of a wide rim 48 and a thick ultra-low pressure tire 50.

A drive shaft 52 is inserted into the left side 42C of the rear arm 42. A gear case 54 is attached to the joint between the left side 42C and the rear side 42b, and a bevel gear 56 (FIG. 4) that transmits the rotation of the drive shaft 52 to the axle 44 is housed here. The rotation of the engine 28 is transmitted from the subshaft 34 of the transmission 30 to the drive shaft 52 via the bevel gear 58, the output shaft 60, and the universal joint 62.

A cylindrical cushion unit 66 is composed of a cylindrical hydraulic damper and a coil spring. One end of this cushion unit 66 is connected to the main pipe 14, and the other end is connected to the rear arm 4.
The cushion unit 66 is pivotally attached to the rear side 42b of the rear arm 42, and expands and contracts as the rear arm 42 swings up and down. In FIG. 1, 68 is a fuel tank, 70 is a seat, and 72 is a fuel tank.

In this embodiment configured as above, the rotation of the engine 28 is controlled by the clutch (not shown), the transmission 30, the bevel gear 58, the output shaft 60, the universal joint 62,
Drive shaft 52, axle 44 via bevel gear 56, rear wheel 4
This will be communicated to 6. When changing gears, partially disengage the clutch,
The engagement points of the dog clutch of the transmission 30 are changed by a speed change operation mechanism (not shown). At this time, all the transmission gears are rotating, so a shock is generated. Bevel gear 58°5
6 has no play, so this impact is directly transmitted to the axle 44 and rim 48. Since the ultra-low pressure tire 50 attached to the rim 48 has a very low air pressure and is highly elastic, the impact transmitted to the rim 48 during gear shifting as described above is sufficiently absorbed by the tire 50. Therefore, this impact is not transmitted to the road surface, and no longitudinal impact is transmitted to the vehicle body.
Although the embodiment of the angle of 4° or more is an application of the present invention to a tricycle, it is clear from the above description that the present invention also includes an application to a two-wheel vehicle, a four-wheel vehicle, etc.

As described above, this invention transmits the engine output to the driving wheels through the constant-mesh transmission and the shaft drive mechanism, and uses ultra-low pressure tires for the driving wheels, so that the speed change of the transmission is The shock caused by this is sufficiently absorbed by the elasticity of this ultra-low pressure tire. Therefore, the impact is not transmitted to the road surface via the ultra-low pressure tires, and the reaction force of the driving force transmitted by the tires to the road surface is smoothed, so that no longitudinal impact is transmitted to the vehicle body.

Therefore, there is no need to provide a large shock absorber in the power transmission mechanism as used in conventional vehicles, and the shock absorber may be small and lightweight, or it may be omitted altogether as in the above embodiment. It becomes possible. Therefore, it becomes possible to reduce the weight of the vehicle and simplify the structure.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a partially omitted plan view, and FIGS. 3 and 4 are a side view and a plan view of the main parts. 28...Engine, 30...Constant mesh transmission, 4
6... Rear wheel as a driving wheel, 50... Ultra low pressure tire, 52... Drive shaft. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] 1. A vehicle in which engine output is transmitted to drive wheels via a constant mesh transmission and a shaft drive mechanism, wherein the drive wheels are equipped with ultra-low pressure tires.