JPH05162553A - Transmission structure of all wheel drive type working vehicle - Google Patents

Abstract

PURPOSE:To provide a transmission structure of an all wheel drive type working vehicle generating no wheel slip in either of forward or rearward running operation by providing a changeover mechanism capable of selecting operation of a one way clutch for forward (rearward) operation which allows preceeding rotation with respect to the drive wheels of drive steering wheels at the time of forward (backward) operation. CONSTITUTION:Two one way clutches 8, 9 which differ in their work rotation directions are provided as those for forward and rearward operations. A changeover mechanism B for selecting the operations of the clutches 8, 9 is provided, and thereby the clutch for forward operation 8 is selectively set at the time of forward operation and drive steering wheels are rotated in advance with respect to drive wheels. At the time of rearward operation, the clutch for rearward operation is selectively set and the drive steering wheels are rotated in advance with respect to the drive wheels. It is thus possible to prevent generation of slip or brake phenomemon in the wheels caused by turning running operation.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、４輪駆動型の芝刈機と
かガーデントラクタといった全輪駆動型作業車の伝動構
造に係り、詳しくは、旋回走行に伴う前後車輪の内輪差
による悪影響がない良好な伝動状態を得る技術に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission structure of an all-wheel drive type work vehicle such as a four-wheel drive type lawnmower or a garden tractor, and more specifically, there is no adverse effect due to a difference in inner wheels between front and rear wheels due to turning traveling. The present invention relates to a technique for obtaining a good transmission state.

【０００２】[0002]

【従来の技術】一般に、旋回走行時では操向輪と非操向
輪とに内輪差が生じるので、４輪駆動車では前もしくは
後輪にスリップを伴いながら旋回走行するようになると
ともに、小旋回時には顕著な内輪差によるブレーキ現象
が生じるという性質がある。そのため、旋回走行を頻繁
に伴う４輪駆動車では、前後車輪への伝動経路に上記性
質を回避させる差動手段を備える場合があり、例えば、
後輪操向型で４輪駆動のフロントマウント芝刈機では前
記差動手段としてワンウェイクラッチを伝動系に装備し
てあり、前進旋回走行時では駆動操向後輪をその駆動回
転速度よりも速く回転できるようにして車輪スリップに
よる芝の損傷が起こらないようにしていた。2. Description of the Related Art Generally, during turning, there is an inner wheel difference between the steered wheels and the non-steered wheels. When turning, there is a characteristic that a braking phenomenon occurs due to a significant inner ring difference. Therefore, in a four-wheel drive vehicle that frequently involves turning, there may be a case where a differential means for avoiding the above property is provided in the transmission path to the front and rear wheels.
A rear-wheel steering type four-wheel drive front-mount lawn mower is equipped with a one-way clutch as the differential means in the transmission system, and the rear steering wheels can be rotated faster than the driving rotation speed during forward turning traveling. This was to prevent damage to the grass due to wheel slips.

【０００３】[0003]

【発明が解決しようとする課題】ところが、前記芝刈機
では、後進旋回走行時には駆動操向後輪はその駆動回転
速度よりも先行回転できないため、前進旋回走行時のよ
うに駆動前輪との内輪差を解消させることが不可とな
り、車輪スリップによる芝損傷が発生することがあっ
た。そこで、図５乃至図７に示すように、後輪操舵型の
４輪駆動作業車における後輪に対する動力の断続を行う
後輪クラッチＡを設け、この後輪クラッチＡを旋回操作
に伴って切る切換機構Ｂを備えたものが考えられた。す
なわち、ドラッグリンク途中に設けられた中継リンク１
の操作アーム２とクラッチシフタ３とをスプリング４を
介して連動連結させ、操向操作されると後輪クラッチＡ
を切りにし、直進状態に操向されると後輪クラッチＡを
入りにするのである。これは、前後進の如何を問わずに
旋回時には機能上２輪駆動状態にさせて車輪スリップや
ブレーキ現象が生じないようにさせるものである。しか
しながら、これでは４輪駆動による強大な駆動力を旋回
中では全く発揮できないことになる欠点があるため、改
善の余地があった。そこで本発明は、ワンウェイクラッ
チによる差動手段を踏襲しながら、前後進のいずれにお
いても内輪差による車輪スリップのない全輪駆動型作業
車の伝動構造を得ることを目的とする。However, in the lawnmower, the rear steering wheel cannot be rotated ahead of the driving rotational speed during the backward turning traveling, so that the inner wheel difference from the driving front wheel is reduced as in the forward turning traveling. It could not be resolved, and there were cases where turf damage due to wheel slip occurred. Therefore, as shown in FIG. 5 to FIG. 7, a rear wheel clutch A for connecting and disconnecting power to the rear wheels in a rear wheel steering type four-wheel drive work vehicle is provided, and the rear wheel clutch A is disengaged in accordance with a turning operation. The one provided with the switching mechanism B was considered. That is, the relay link 1 provided in the middle of the drag link
The operation arm 2 and the clutch shifter 3 of the vehicle are interlocked with each other via the spring 4, and when the steering operation is performed, the rear wheel clutch A
When the vehicle is turned straight and the vehicle is steered straight, the rear wheel clutch A is turned on. This is to prevent the wheel slip and the braking phenomenon from occurring by functionally setting the two-wheel drive state when turning regardless of whether the vehicle is moving forward or backward. However, this has a drawback in that the strong driving force of the four-wheel drive cannot be exerted at all during turning, so there is room for improvement. Therefore, an object of the present invention is to obtain a transmission structure of an all-wheel drive type work vehicle which follows a differential means by a one-way clutch and has no wheel slip due to an inner wheel difference in both forward and backward movements.

【０００４】[0004]

【課題を解決するための手段】上記目的の達成のために
本発明は、機体の前後一方に駆動輪を、他方に操向及び
駆動可能な駆動操向輪を備えるとともに、前進時におけ
る駆動操向輪の駆動輪に対する先行回転を許容する前進
用ワンウェイクラッチと、後進時における駆動操向輪の
駆動輪に対する先行回転を許容する後進用ワンウェイク
ラッチとの夫々を伝動系に装備するとともに、これら両
ワンウェイクラッチの作動を択一的に選択可能な切換機
構を設けてあることを特徴とする。In order to achieve the above object, the present invention provides drive wheels on one side of the front and rear of the machine body, and drive steering wheels on the other side capable of steering and driving, and driving drive during forward movement. In addition to equipping the transmission system with a forward one-way clutch that allows the preceding rotation of the directional wheel to the drive wheel and a reverse one-way clutch that allows the preceding rotation of the drive steering wheel to the drive wheel during reverse travel, It is characterized in that a switching mechanism capable of selectively selecting the operation of the one-way clutch is provided.

【０００５】[0005]

【作用】つまり、後進旋回走行時でも駆動操向輪の先行
回転を許容するワンウェイクラッチを備えてあれば前述
した不都合を解消させることが可能になるという考えで
ある。ところが、互いに作用回転方向の異なる２個のワ
ンウェイクラッチを双方共に単に装備すると伝動不能に
なってしまう不具合がある。そこで、本発明では前進用
と後進用との２個のワンウェイクラッチを択一的に選択
する切換機構を設けることにより、前進時には前進用ワ
ンウェイクラッチを、後進時には後進用ワンウェイクラ
ッチを選択設定でき、前後進のいずれを問わず前述した
作動手段が発揮され、旋回走行に伴う車輪スリップやブ
レーキ現象を回避することができる。In other words, it is an idea that the above-mentioned inconvenience can be eliminated by providing a one-way clutch that allows the drive steering wheel to rotate ahead even when the vehicle is traveling in reverse. However, if both two one-way clutches having different acting rotational directions are simply provided, there is a problem that transmission becomes impossible. Therefore, in the present invention, by providing a switching mechanism that selectively selects two one-way clutches for forward travel and reverse travel, it is possible to selectively set the forward one-way clutch during forward travel and the reverse one-way clutch during reverse travel, The actuating means described above is exerted regardless of whether the vehicle is moving forward or backward, and it is possible to avoid the wheel slip and the braking phenomenon that accompany the turning traveling.

【０００６】[0006]

【発明の効果】従って、ダブルのワンウェイクラッチと
切換機構とによる作動手段により、ワンウェイクラッチ
の特質、すなわち、上記車輪スリップの回避作用を持ち
ながら非操向輪が駆動スリップ（泥地や積雪等によっ
て）した場合には直ちに操向輪が駆動輪となって全輪駆
動の威力を有効に発揮できるという特質を活かしながら
内輪差による不都合を解消できる伝動構造を提供するこ
とができた。これは、例えば一般的な前後デフ装置を備
えた場合や前述した後輪クラッチの入切り手段の場合に
比べて、泥地や積雪等による悪路面でも前後輪を確実に
同時駆動できる点で有利である。Therefore, by the operating means of the double one-way clutch and the switching mechanism, the characteristic of the one-way clutch, that is, the non-steering wheel has a driving slip (due to mud or snow, etc.) while having the above-mentioned wheel slip avoiding action. In this case, it was possible to provide a transmission structure capable of eliminating the inconvenience due to the difference in the inner wheels while taking advantage of the characteristic that the steered wheels immediately become the driving wheels and the power of all-wheel drive can be effectively exhibited. This is advantageous in that the front and rear wheels can be driven simultaneously on a bad road surface due to mud, snow, etc., compared to the case where a general front and rear differential device is provided and the above-mentioned rear wheel clutch on / off means. Is.

【０００７】[0007]

【実施例】以下に、本発明の実施例を図面に基づいて説
明する。図４に全輪駆動型作業車の一例である後輪操舵
型の４輪駆動フロントマウント芝刈機が、そして図１に
前輪１５と後輪１６との差動手段Ｃが示されている。図
４において、１５は駆動前輪、１６は駆動操向後輪、Ｍ
はモア、Ｅはエンジン、ＨはＨＳＴ、１７はミッション
ケース、１８は操縦部である。差動手段Ｃは、ミッショ
ンケース１７の図示しない出力軸に連動連結される駆動
軸５と後輪用デフ装置２０に連動連結される従動軸６と
に跨がるユニットで構成されている。つまり、前進用と
後進用の２個のワンウェイクラッチ８，９を従動軸６に
連動連結される支軸１９に外嵌装着し、これら両ワンウ
ェイクラッチ８，９の外周にスプライン咬合する噛合回
転体１０、この噛合回転体１０を前進用ワンウェイクラ
ッチ８側にスラストワッシャ機能を持つ摩擦板１１を介
して押圧付勢する圧縮バネ１２、駆動軸５にスプライン
外嵌する駆動回転体１３、及び駆動回転体１３と噛合回
転体１０とで成るカム機構Ｂ等を、両軸５，６の接続部
を覆う差動ケース７に内装して差動手段Ｃが構成されて
いる。つまり、駆動軸５と一体回転することになる噛合
回転体１０を軸方向にスライドさせ、前進時には前進用
ワンウェイクラッチ８に、そして後進時には後進用ワン
ウェイクラッチ９に択一的に選択して咬合させるのであ
る。尚、１４は圧縮バネ１２の受け部材であり、従動軸
６と一体回転する。Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows a rear-wheel steering type four-wheel drive front mount lawn mower which is an example of an all-wheel drive type work vehicle, and FIG. 1 shows a differential means C between the front wheels 15 and the rear wheels 16. In FIG. 4, reference numeral 15 is a front wheel, 16 is a rear steering wheel, and M is a rear wheel.
Is a mower, E is an engine, H is an HST, 17 is a mission case, and 18 is a control section. The differential means C is composed of a unit that straddles a drive shaft 5 interlockingly connected to an output shaft (not shown) of the transmission case 17 and a driven shaft 6 interlockingly connected to the rear wheel differential device 20. That is, two forward and backward one-way clutches 8 and 9 are externally fitted and mounted on a support shaft 19 that is interlocked with the driven shaft 6, and a meshing rotary body that spline-engages with the outer peripheries of the two one-way clutches 8 and 9. 10, a compression spring 12 that biases the meshing rotating body 10 toward the forward one-way clutch 8 through a friction plate 11 having a thrust washer function, a drive rotating body 13 that is spline-fitted to the drive shaft 5, and a drive rotating body. The differential mechanism C is configured by incorporating the cam mechanism B and the like including the body 13 and the meshing rotary body 10 in the differential case 7 that covers the connecting portions of the shafts 5 and 6. That is, the meshing rotating body 10 that rotates integrally with the drive shaft 5 is slid in the axial direction, and is selectively engaged with the forward one-way clutch 8 during forward travel and the reverse one-way clutch 9 during reverse travel. Of. Reference numeral 14 is a receiving member for the compression spring 12 and rotates integrally with the driven shaft 6.

【０００８】前記カム機構Ｂは、図２に示すように、駆
動回転体１３と噛合回転体１０との双方に形成された周
方向に対して緩く傾斜させたスライド面１３ａ，１０ａ
とストップ部１３ｂ，１０ｂで構成される。作用を説明
すると、駆動軸５が図３（イ）において矢印（ａ）方向
に回転する前進時には、両ストップ部１３ｂ，１０ｂが
それらの前面壁１３ｃ，１０ｃが接当する比較的広い接
触面積での駆動状態であり、図１（イ）に示すように噛
合回転体１０は圧縮バネ１２の押圧作用によって前進用
ワンウェイクラッチ８と咬合する。そして、駆動軸５が
図３（ロ）において矢印（ｂ）方向に回転する後進時に
は、駆動トルクにより圧縮バネ１２の押圧付勢力に抗し
て両ストップ部１３ｂ，１０ｂが互いのスライド面１０
ａ，１３ａに乗り上がって周方向にズレ変位し、背壁面
１３ｄ，１０ｄどうしが接当する駆動状態となり、それ
によって図１（ロ）に示すように、噛合回転体１０は後
進用ワンウェイクラッチ９に咬合するのである。つま
り、この差動手段Ｃでは駆動軸５の回転変化によって自
動的にワンウェイクラッチの択一選択操作が行われるよ
うに構成されており、カム機構Ｂが選択機構に相当す
る。As shown in FIG. 2, the cam mechanism B has sliding surfaces 13a, 10a formed on both the driving rotary body 13 and the meshing rotary body 10 and gently inclined with respect to the circumferential direction.
And stop portions 13b and 10b. The operation will be described. When the drive shaft 5 rotates forward in the direction of the arrow (a) in FIG. 3 (a), both stop portions 13b, 10b have a relatively wide contact area with which their front walls 13c, 10c abut. 1 (A), the meshing rotating body 10 meshes with the forward one-way clutch 8 by the pressing action of the compression spring 12. Then, when the drive shaft 5 rotates backward in the direction of the arrow (b) in FIG. 3B, the drive torque resists the pressing biasing force of the compression spring 12 so that the two stop portions 13b and 10b slide against each other on the sliding surface 10.
1a, 13a, and the displacement in the circumferential direction is displaced, and the back wall surfaces 13d, 10d are brought into contact with each other to be in a driving state, whereby the meshing rotating body 10 moves the reverse one-way clutch 9 as shown in FIG. Bite into. That is, in the differential means C, the one-way clutch alternative selection operation is automatically performed according to the rotation change of the drive shaft 5, and the cam mechanism B corresponds to the selection mechanism.

【０００９】〔別実施例〕上記実施例では自動的に切換
機構が作動するが、例えば人為操作レバーによって２個
のワンウェイクラッチを切換えるようにするとか、ある
いは、一定角度以上に操向輪が操舵されるとワンウェイ
クラッチが作動するようにしても良い。[Other Embodiments] In the above embodiment, the switching mechanism is automatically operated. For example, two one-way clutches are switched by an artificial operation lever, or the steering wheel is steered at a certain angle or more. If so, the one-way clutch may be activated.

【００１０】尚、特許請求の範囲の項に図面との対照を
便利にするために符号を記すが、該記入により本発明は
添付図面の構成に限定されるものではない。It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

【図面の簡単な説明】[Brief description of drawings]

【図１】差動手段の構造を示す断面図FIG. 1 is a sectional view showing the structure of a differential means.

【図２】カム機構の構造を示す要部の分解斜視図FIG. 2 is an exploded perspective view of essential parts showing a structure of a cam mechanism.

【図３】カム機構の作動状態を示す作用図FIG. 3 is an operation diagram showing an operating state of a cam mechanism.

【図４】芝刈機の側面図[Figure 4] Side view of lawn mower

【図５】比較例における後輪クラッチの操作構造を示す
断面図FIG. 5 is a cross-sectional view showing an operation structure of a rear wheel clutch in a comparative example.

【図６】比較例における後輪クラッチの断面図FIG. 6 is a sectional view of a rear wheel clutch in a comparative example.

【図７】比較例における芝刈機の平面図FIG. 7 is a plan view of a lawnmower in a comparative example.

【符号の説明】[Explanation of symbols]

８ 前進用ワンウェイクラッチ ９ 後進用ワンウェイクラッチ １５ 駆動輪 １６ 駆動操向輪 8 Forward one-way clutch 9 Reverse one-way clutch 15 Drive wheel 16 Drive steering wheel

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 機体の前後一方に駆動輪（１５），（１
５）を、他方に操向及び駆動可能な駆動操向輪（１
６），（１６）を備えるとともに、前進時における前記
駆動操向輪（１６），（１６）の前記駆動輪（１５），
（１５）に対する先行回転を許容する前進用ワンウェイ
クラッチ（８）と、後進時における前記駆動操向輪（１
６），（１６）の前記駆動輪（１５），（１５）に対す
る先行回転を許容する後進用ワンウェイクラッチ（９）
との夫々を伝動系に装備するとともに、これら両ワンウ
ェイクラッチ（８），（９）の作動を択一的に選択可能
な切換機構（Ｂ）を設けてある全輪駆動型作業車の伝動
構造。1. Driving wheels (15), (1
5) to the other, driving steerable wheels (1
6) and (16), and the drive wheels (15) of the drive steering wheels (16) and (16) when moving forward,
A forward one-way clutch (8) that allows preceding rotation with respect to (15), and the drive steering wheel (1) during reverse travel.
6), (16) one-way clutch (9) for reverse drive which allows the preceding rotation of the drive wheels (15), (15)
And a transmission system equipped with a switching mechanism (B) capable of selectively selecting the operation of both one-way clutches (8) and (9). .