JPH068737A - Power unit for working vehicle - Google Patents

Abstract

PURPOSE:To form a transmission device utilizing a CVT in a compact state by integral constitution of the transmission device and a vertical shaft type engine. CONSTITUTION:A plurality of drive rotary bodies 7 revolved centering around the axis of a main shaft 3 are arranged around the main shaft 3 and a gear shifting part 10 capable of being freely shifted in an axial direction is brought into contact with and throughout the drive rotary bodies 7 to form a friction type continuously variable gear shifting part 1. An input rotary body member 20 for driving the drive rotary body 7 is relatively rotatably fit externally of the main shaft 3. The two end parts of the main shaft 3 are extended to the outside of a gear shift case C with which the continuously variable gear shifting part 1 is covered, and a power take-out part 12 for driving a running device is arranged to each of the extended end parts of the main shaft. A prime mover E having a vertical output shaft 23 interlocked and coupled to the input rotary body member 20 through a bevel gear mechanism 25 is coupled to the gear shift case C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction type continuously variable transmission (Continuous Variable Trans).
The present invention relates to a power unit using a miss (hereinafter abbreviated as CVT)], and is suitable for a small work vehicle.

[0002]

2. Description of the Related Art A CVT is a structure in which a ring-shaped speed changing member such as a taper cone or a disk that comes into contact with a driving rotary member is axially shifted to change the radius of a contact point with the driving rotary member to continuously change the speed. Therefore, there is an advantage that it can be made compact and continuously variable transmission can be output. Therefore, it has been planned to employ a binder or the like in a small work vehicle as proposed in Japanese Patent Application Laid-Open No. 3-177649 filed by the present applicant.

[0003]

Therefore, it has been considered to use the CVT for a transmission device for a traveling device of a two-wheel drive type work vehicle having a pair of driving wheels such as a small lawn mower or a management machine. There is. However, the structure disclosed in the above publication is based on the premise that a gear mechanism, a chain mechanism, and the like are interposed between the transmission device and the traveling device, and that the transmission device is arranged at the rear position of the drive wheels. If the transmission having the above structure is used as it is for a two-wheel drive type work vehicle, an extra gear mechanism or the like is required, and it seems that there is room for improvement as a transmission device for the two-wheel drive type work vehicle. An object of the present invention is to provide a transmission device using CVT suitable for a two-wheel drive type work vehicle by restructuring the structure without waste of the mechanism.

[0004]

In order to achieve the above object, the present invention provides a plurality of drive rotating bodies which are revolved around a main shaft around an axis of the main shaft and which are driven. A friction-type continuously variable transmission unit is configured by bringing a speed-changeable member that is shiftable in the axial direction over the rotor into contact, and an input rotor member for driving the drive rotor is externally fitted relative to the main shaft so as to be rotatable. Then, both ends of the main shaft are extended to the outside of the transmission case that covers the continuously variable transmission part, and a power take-out portion for driving the traveling device is provided at each of the extended main spindle ends. Is characterized in that a prime mover having a vertically oriented output shaft that is interlocked and coupled via a bevel gear mechanism is coupled to a transmission case to form a power unit for a working vehicle.

[0005]

According to the above-mentioned characteristic structure, the input is transmitted to the input rotary member, and the output constitutes the CVT in a state of being taken out from the main shaft, and the main shaft which is the output shaft is extended outside the speed change case. For example, a wheel type work vehicle (walking lawn mower, etc.) may be configured by directly attaching wheels to each of the extending spindles, or a sprocket may be attached to each of the extending spindles via a gear reduction mechanism. It becomes easy to set such as configuring a crawler type work vehicle (management machine, etc.). In other words, by providing the input section at one place and the pair of output sections at positions symmetrical to the shift case,
A transmission device of a suitable form can be configured for a two-wheel drive type work vehicle that requires a pair of left and right drive wheels. Further, in the present application, since the output of the vertical axis type engine is bevel-transmitted to the input rotary member, and further, the engine itself is configured as a power unit that is integrated with a transmission case that covers the transmission device,
The power unit can be arranged between the left and right drive wheels in a state where the front-rear space required for the power unit can be saved, and due to the existence of the bevel gear mechanism, for example, as shown in FIGS. 3 and 4, the mower M is arranged on the lower abdomen of the body. The external power take-out function such as the power take-out to the car and the power take-out to the sweeper 29 connected to the rear part of the machine can be set by a simple modification by additionally setting the bevel mechanism.

[0006]

As a result, the integrated structure of the power transmission device and the vertical axis type engine by devising the structure of the CVT makes it a small two-wheel drive work vehicle such as a small lawn mower or management machine or a self-propelled cart. It was possible to provide a suitable CVT-based transmission in a rational state, which was developed into a power unit that can be made more compact as a whole.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a power unit suitable for a small transport vehicle or the like. This power unit has a vertically oriented output shaft 2
A vertical engine E having 3 and a transmission device D are integrally formed, and the transmission device D is composed of a CVT portion Dc and a transmission portion Dd. The transmission device D will be described in detail. A transmission case C including a left case Ca and a right case Cb is provided with a main shaft 3 which has both ends supported by ball bearings 2, 2 and 4 and also serves as an output shaft.
A carrier 5 having a rotation input portion integrally formed with the main shaft 3 is idly supported. Three taper cones 7 having support shafts 6 engaged with and supported by the upper and lower holding portions formed on the carrier 5 are arranged, and a disk-shaped rotating body 8 in contact with the large diameter side of the taper cones 7, and This rotating body 8
Automatic pressure adjusting mechanism A for adjusting the contact pressure between the taper cone 7 and the taper cone 7
Each is provided coaxially with the main shaft 3. A ring-shaped speed change member 10 and a taper cone 7 are arranged so as to be shiftable along a rod 9 mounted on a speed change case C in a state of being parallel to the axis P of the main shaft 3 and circumscribing each taper cone 7. The transmission unit 1 and the taper cone 7 are provided with the support member 11 which is in contact with the annular recesses 7a formed on the small diameter side and which is in contact with the annular recess 7a, and which is supported by the main shaft 3 in a free-rotating manner. It is configured. Further, both ends of the main shaft 3 are extended to the outside of the speed change case C so that the power take-out portion 12,
12 is formed. In this CVT portion Dc, ball bearings 2 and 2 are provided between the carrier base portion 5A serving as an input portion and the spindle 3, needle bearings 16 are provided between the support member 11 and the spindle 3, and the thrust bearing is also provided. 17 is interposed between the support member 11 and the collar 21. With the automatic pressure adjusting mechanism A including a transmission member 18 externally fitted to the main shaft 3 so that torque can be transmitted, a rotating body 8 slidably movable along the axis P, and a ball 19 interposed between the two. As the load increases, the rotating body 8 and the tapered cone 7 are pressed against each other more strongly. Transmission unit D
The d is configured by accommodating the carrier 5, the engine output shaft 23, the input bevel mechanism 25 for interlocking these, and the like in the right case portion Cb. The carrier 5 is composed of a carrier base portion 5A and a carrier body 5B. The carrier body 5B has plate-like support plates 13 made of sheet metal for the vertical penetrating protrusions 6A, 6B of the support shaft 6 in a state of penetrating the taper cone 7. The carrier 5 is configured by being fixed relative to the support case 14 that is bolted to the support plate 13, and the support plate 13 is bolted to the carrier base portion 5A. The support shaft 6 rotatably supports the tapered cone 7 by means of needle bearings 22, 22. Then, in this transmission portion Dd, the input bevel mechanism 25 is formed by the input bevel gear 20 formed on the carrier base portion 5A and the drive bevel gear 24 of the engine output shaft 23.
Is configured.

The operation of the CVT portion Dc will be briefly described. When the speed change member 10 is shifted by rotating the speed change shaft 15, the taper cone 7 from the axis of rotation of the taper cone 7 at the position where the speed change member 10 contacts. Since the radius changes, that is, the circumferential length of the tapered cone 7 changes at the position where the speed change member 10 contacts, the speed change member 1 is rotated when the carrier 5 is rotated by a unit amount.
The rotation amount of the taper cone 7 that rotates following the inner surface of 0 changes, and the rotation speed of the rotating body 8 to which power is transmitted from the taper cone 7 changes with respect to the rotation speed of the carrier 5. The continuously variable power for traveling is transmitted to each of the power take-off units 12. FIG. 2 is a rear view of the work vehicle (lawn mower, etc.), and rear wheels 26 are attached to the left and right power take-off portions 12, respectively.

Next, an application example of the above transmission device will be briefly described. FIG. 3 shows a power unit suitable for a mid-mount riding lawn mower. The transmission unit Dd includes the carrier 5, the engine output shaft 23, the PTO shaft 27, and the input bevel mechanism 25 and the output bevel mechanism 28 that interlock these components with each other in the right case C.
It is stored in b. In this transmission portion Dd, the input bevel gear 20 formed on the carrier 5 and the drive bevel gear 24 of the engine output shaft 23 constitute an input bevel mechanism 25, and the output bevel mechanism 28 also serves as the input bevel gear 20. The PTO shaft 27 and the rotary blade 30 of the mid-mounted mower M are attached to the cutting blade clutch 3
It is interlockingly connected through 1. Further, as shown in FIG. 4, the first PTO shaft 32 facing forward and the second PT facing rearward.
When the power unit including the O-axis 33 and the transmission portion Dd is configured, the power unit is suitable for a work vehicle including a plurality of work devices such as a mid-mount mower lawnmower with a sweeper 29. Incidentally, it is convenient if the speed change member 10 is made of resin (engineering plastic such as polyacetal) or made of resin containing a steel reinforcing ring 10a as shown in FIG. The reinforcing ring 10a may have a structure in which the outer peripheral side is exposed as shown in FIG. Further, there is also a means in which the rotating body 8 and the supporting member 11 are made of the above-mentioned resin, or only the contact portion with the tapered cone 7 is made of resin as shown in FIG. Further, there is an idea that all the components of the CVT portion Dc are made of resin.

It should be noted that although reference numerals are given in the claims for convenience of comparison with the drawings, the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a developed sectional view showing the structure of a power unit.

FIG. 2 is a system diagram of a drive unit showing an example of use of the power unit shown in FIG.

FIG. 3 is a system diagram showing a first application example of a power unit.

FIG. 4 is a system diagram showing a second application example of the power unit.

FIG. 5 is a sectional view of a speed change member.

FIG. 6 is a sectional view of a speed change member.

FIG. 7 is a sectional view of a supporting member portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission part 3 Main shaft 7 Drive rotating body 10 Transmission member 12 Power extraction part 20 Input rotating member 23 Output shaft 25 Bevel gear mechanism C Transmission case E Engine

Claims (1)

[Claims] 1. A plurality of drive rotating bodies (7) revolved around a main shaft (3) around an axis of the main shaft (3).
And a friction-variable continuously variable transmission section (1) is configured by bringing a speed-changeable member (10) which is shiftable in the axial direction over the drive rotor (7) into contact with the drive rotor. (7)
A transmission case (C) for externally fitting an input rotary member (20) for driving the main shaft (3) to the main shaft (3) so that both ends of the main shaft (3) cover the continuously variable transmission (1). ) A power take-out portion (12) for driving a traveling device is provided on each of the extended spindle ends, and the bevel gear mechanism (25) is provided on the input rotary member (20). A power unit for a work vehicle, comprising a prime mover (E) having a vertically oriented output shaft (23) interlocked and linked to the shift case (C).