Patent Description:
There is a work vehicle including a driving device which drives a traveling device and which allows speed change, a pivot-operable operating lever which performs speed change operation of the driving device, a rotary type potentiometer which detects an operation position of the operating lever, and a controlling means which performs speed change of the driving device based on a detection result of the potentiometer.

Such type of work vehicle is disclosed in <CIT>, for example, wherein a mower is shown as a work vehicle.

In the mower shown in <CIT>, there are provided an electric motor for travelling as the driving device which drives rear wheels, and a traveling speed change lever as the operating lever which performs speed change of the electric motor for traveling. Also, there are provided a potentiometer which detects an operation position of the traveling speed change lever, and a control device as the controlling means which controls the electric motor for traveling based on detection information of the potentiometer.

In the work vehicle described above, as an interlocking mechanism which interlocks the operating lever with the potentiometer, the mechanism shown in <FIG> can be conceivable. That is, there are provided an input part <NUM> which pivots in interlocking with pivoting of the operating lever <NUM> about a pivot axis P1 of the operating lever <NUM> as a pivot, and inputs power of the operating lever <NUM>; and an output part <NUM> which extends from a rotary operation shaft 13b of a potentiometer <NUM>, pivots about a rotary axis P2 of the rotary operation shaft 13b as the pivot, and outputs power of the input part <NUM> to the rotary operation shaft 13b. The input part <NUM> and the output part <NUM> are interlocked via an elongate hole <NUM> provided at the input part <NUM> and via a connecting pin <NUM> provided at the output part <NUM>, the connecting pin <NUM> slidably engaging with the elongate hole <NUM>.

In the case of this interlocking mechanism, if dust gets into the elongate hole, operational failure occurs that motion of the connecting pin is disabled due to dust becoming resistance, or that the connecting pin does not move due to the dust getting stuck. Also, if the connecting pin is adapted to slide smoothly, connecting play between the input part and the output part develops due to the elongate hole, and detection error due to the potentiometer occurs.

Therefore, there is a demand for a work vehicle in which the interlocking mechanism moves smoothly and an accurate detection result can be obtained.

<CIT> discloses a work vehicle including a hydrostatic stepless change speed device and a change speed pedal mechanism for changing speeds.

<CIT> discloses a work vehicle comprising a position setting device including a position lever.

In view of the above, the work vehicle with a configuration as below is proposed.

wherein the work vehicle further comprises a damper which is connected to the input part and which acts on the operating lever, the damper being connected to/between the free end side part of the input part, and a part of the vehicle body frame located on the rear side relative to a part of the vehicle body frame supporting the operating lever.

With this configuration, the input part and the output part are operably connected via the connecting pin to pivot about the common axis as the pivot, whereby pivoting of the operating lever is transmitted to a rotary operation shaft of the potentiometer. Thus, there is no need to provide a connecting hole, such as an elongated hole, which is sized larger than the connecting pin, at the input part and the output part. Therefore, an interlocking mechanism may move smoothly without causing operational failure and the potentiometer may operate in accurate association with the operating lever, so that an accurate detection result may be obtained.

With this configuration, the damper may act on the operating lever, with a simple configuration in which the input part is utilized for a member which interlocks the damper with the operating lever.

In a preferred embodiment, the rotary operation shaft protrudes from a meter case of the potentiometer to a side where the operating lever is located.

With this configuration, compared with protruding of the rotary operation shaft from the meter case to an opposite side of the operating lever side, the output part may be positioned closer to the operating lever, with a smaller size in a direction along a pivot axis and a rotary axis of the interlocking mechanism.

In a preferred embodiment, the input part is located on a side where the potentiometer is located, relative to the operating lever.

With this configuration, compared with locating the input part on the opposite side of the side where the potentiometer is located relative to the operating lever, the input part may be located closer to the potentiometer, with a smaller size in the direction along the pivot axis and the rotary axis of the interlocking mechanism.

Other features and advantages therefrom will be apparent upon reading the description as below.

An embodiment of the invention will be described hereinafter with reference to the drawings.

In the following description, with regard to a traveling vehicle body of a riding-type mower (an example of "work vehicle"), the direction of arrow F shown in <FIG> and <FIG> is defined as "front side of the vehicle body", the direction of arrow B shown is defined as "rear side of the vehicle body", the direction of arrow U shown in <FIG> is defined as "upper side of the vehicle body", the direction of arrow D is defined as "lower side of the vehicle body", the direction of arrow L shown in <FIG> is defined as "left side of the vehicle body", and the direction of arrow R is defined as "right side of the vehicle body".

As shown in <FIG> and <FIG>, a riding-type mower is provided with a traveling vehicle body <NUM> including a pair of right and left front wheels <NUM> freely rotatably and a pair of right and left rear wheels <NUM> (an example of "traveling device") drivably. The pair of right and left front wheels <NUM> are configured as a caster wheel type. At a front part of the traveling vehicle body, a driving section <NUM> having a driver's seat <NUM> is formed. At the driving section <NUM>, there are provided the driver's seat <NUM> and a pair of right and left operating levers <NUM> which perform traveling operation and steering operation of the traveling vehicle body. Downwardly of the driving section <NUM>, there is provided a pair of right and left traveling electric motors <NUM> (an example of "driving device") which separately drive the pair of right and left rear wheels <NUM>. At a rear part of the traveling vehicle body, there is provided a battery pack <NUM> which supplies electric power to the pair of right and left traveling electric motors <NUM>. Between the front wheels <NUM> and the rear wheels <NUM>, there is provided a mowing device <NUM>. The mowing device <NUM> is supported to a vehicle body frame <NUM> via a link mechanism <NUM> which lifts the mowing device <NUM> up/down relative to the driving vehicle body. The mowing device <NUM> includes a cutting blade housing <NUM>, and inside the cutting blade housing <NUM>, there is provided a cutting blade <NUM> which is configured to be rotatable and drivable, about a support shaft (not shown) as a pivot which extends in a direction along the vertical direction of the vehicle body.

As shown in <FIG> and <FIG>, at the driving section <NUM>, there are provided the pair of right and left operating levers <NUM> which perform traveling operation and steering operation of the traveling vehicle body. The right and left operating levers <NUM> are provided in distribution on two lateral sides of the driver's seat <NUM>.

As shown in <FIG>, the respective right and left operating levers <NUM> are configured such that a potentiometer <NUM> detects an operation position of the operating lever <NUM> at the time when the operating lever <NUM> is pivotally operated about a pivot axis P1 as a pivot. The potentiometers <NUM> of the right and left operating levers <NUM> are linked to a control device <NUM>. The left traveling electric motor <NUM> as a speed-variable driving device which drives the left rear wheel <NUM>, and the right traveling electric motor <NUM> as a speed-variable driving device which drives the right rear wheel <NUM> are linked to the control device <NUM>. In the right and left traveling electric motors <NUM>, there are provided controllers <NUM> which perform switching between forward drive and reverse drive of the respective traveling electric motors <NUM>, and changing forward rotational speed and reverse rotational speed of the respective traveling electric motors <NUM>. The control device <NUM> is configured by utilizing a microcomputer, and the control device <NUM> includes a controlling means <NUM> which operates the traveling electric motors <NUM> by controlling the respective controllers <NUM>.

When the left operating lever <NUM> is pivotally operated in a front-rear direction of the vehicle body, a detection result by the potentiometer <NUM> corresponding to the left operating lever <NUM> is received by the control device <NUM>, and the controlling means <NUM> acts based on the received detection result. Then, the left controller <NUM> is controlled by the controlling means <NUM>, and the left traveling electric motor <NUM> is operated by the controller <NUM>. When the right operating lever <NUM> is pivotally operated in the front-rear direction of the vehicle body, the right traveling electric motor <NUM> is operated by the controller <NUM> in the same way as when the left operating lever <NUM> is pivotally operated. When the right and left traveling electric motors <NUM> are operated so as to rotate at a same rotation speed as a forward-movement driving state, the right and left rear wheels <NUM> are driven at the same rotation speed on a forward moving side, and the traveling vehicle body travels straight to the forward moving side. When the right and left traveling electric motors <NUM> are operated so as to rotate at a same rotation speed as a reverse-movement driving state, the right and left rear wheels <NUM> are driven at the same rotation speed on a reverse moving side, and the traveling vehicle body travels straight to the reverse moving side. When the right and left traveling electric motors <NUM> are operated so as to rotate at different rotation speeds, the right and left rear wheels <NUM> are driven at different rotation speeds, and the traveling vehicle body turns, with the rear wheel <NUM> on a lower speed side being on an inner side in turning.

As shown in <FIG> and <FIG>, each of the right and left operating levers <NUM> has a supporting block <NUM> which is attached to a base part of the operating lever <NUM>. As shown in <FIG>, <FIG> and <FIG>, the operating lever <NUM> is supported to right and left supporting members <NUM> via the supporting block <NUM>. The right and left supporting members <NUM> are configured by a lever guide <NUM> (see <FIG>) which is supported to the vehicle body frame <NUM> in such a manner as to cover the supporting block <NUM>, etc. The supporting block <NUM> has a boss part 17a formed at a lower part of the supporting block <NUM> and a support shaft <NUM> fitted in the boss part 17a, and is pivotably supported to the right and left supporting members <NUM> via the support shaft <NUM>. The support shaft <NUM> has a pivot axis P1 thereof extending in a direction along a lateral width direction of the vehicle body. Each of the right and left operating levers <NUM> is supported to the supporting members <NUM> associated therewith, to be pivotally operable in the front-rear direction of the vehicle body about the pivot axis P1 as the pivot.

As shown in <FIG>, the right/left potentiometer <NUM> has a rotary operation shaft 13b protruding from a meter case 13a. The potentiometer <NUM> is configured of a rotation type, wherein in response to rotary operation of the rotary operation shaft 13b, the potentiometer <NUM> is configured to output, as a detection result, an electric signal corresponding to an operation position of the rotary operation shaft 13b.

As shown in <FIG>, <FIG> and <FIG>, the potentiometer <NUM> associated with the right/left operating lever <NUM> is supported to one of the supporting members <NUM> in an attachment posture in which the rotary operation shaft 13b protrudes from the meter case 13a toward the operating lever <NUM> and in which a rotary axis P2 of the rotary operation shaft 13b extends concentric with the pivot axis P1 of the operating lever <NUM>. The one of the supporting members <NUM> which supports the potentiometer <NUM> is one located on an inner side in a lateral direction of the vehicle body relative to the supporting block <NUM>.

As shown in <FIG> and <FIG>, the potentiometer <NUM> is supported to the supporting member <NUM> via a pair of attaching shafts 13c. Specifically, as shown in <FIG>, the potentiometer <NUM> includes the pair of attaching shafts 13c. As shown in <FIG> and <FIG>, the pair of attaching shafts 13c are arranged between the meter case 13a and the supporting member <NUM>, and fastened and connected to the meter case 13a and the supporting member <NUM> by a screw member 13d. The pair of attaching shafts 13c are arranged in distribution on a front side and a rear side relative to the rotary operation shaft 13b. As shown in <FIG> and <FIG>, the pair of attaching shafts 13c are interconnected by a connecting member <NUM>. The connecting member <NUM> is connected to a portion of the attaching shaft 13c closer to the meter case 13a and away from the supporting member <NUM>.

The operating lever <NUM> and the rotary operation shaft 13b of the potentiometer <NUM> are interlocked by an interlocking mechanism <NUM>. As shown in <FIG>, <FIG> and <FIG>, the interlocking mechanism <NUM> includes the input part <NUM> which inputs pivoting of the operating lever <NUM>, an output part <NUM> which outputs power inputted by the input part <NUM> to the rotary operation shaft 13b of the potentiometer <NUM>, and a connecting pin <NUM> which operably connects the input part <NUM> and the output part <NUM> with each other.

As shown in <FIG>, <FIG> and <FIG>, the input part <NUM> is arranged on a side where the potentiometer <NUM> is located relative to the operating lever <NUM>, and is supported to the supporting block <NUM>. Specifically, as shown in <FIG>, the input part <NUM> includes an attaching hole 23a which is provided in a base part of the input part <NUM>, and two first connecting holes 23b which are provided in distribution to an upper part and a lower part relative to the attaching hole 23a. As shown in <FIG>, <FIG> and <FIG>, the base part of the input part <NUM> is fitted on the boss part 17a of the supporting block <NUM> via the attaching hole 23a. The base part of the input part <NUM> is connected to the supporting block <NUM> via connecting bolts <NUM> which are attached to the two first connecting holes 23b and are fastened to a supporting part 17b (see <FIG>) formed in the supporting block <NUM>. The input part <NUM> is supported to the supporting block <NUM>; and when the operating lever <NUM> is pivoted in the front-rear direction of the vehicle body, the input part <NUM> is pivotally operated about the pivot axis P1 as the pivot, by the supporting block <NUM> which pivots together with the operating lever <NUM>.

As shown in <FIG>, <FIG> and <FIG>, the output part <NUM> is supported to the rotary operation shaft 13b of the potentiometer <NUM>, with the rotary operation shaft 13b being rotatable. Specifically, as shown in <FIG>, the output part <NUM> has a first connecting hole 24a which is provided in a base part of the output part <NUM>. As shown in <FIG> and <FIG>, the output part <NUM> is fitted on the rotary operation shaft 13b of the potentiometer <NUM> via the first connecting hole 24a. With non-circular shapes of the first connecting hole 24a and of the rotary operation shaft 13b, the output part <NUM> is engaged with the rotary operation shaft 13b not to be rotatable relative thereto. The output part <NUM> is received and supported by the connecting member <NUM>, which is located on an opposite side of the meter case 13a relative to the output part <NUM>, so as not to come off the rotary operation shaft 13b.

As shown in <FIG>, <FIG> and <FIG>, the connecting pin <NUM> is connected to a free end side part of the input part <NUM> and a free end side part of the output part <NUM>, thus operably connecting the input part <NUM> and the output part <NUM>. Specifically, as shown in <FIG>, the connecting pin <NUM> includes a screw shaft portion 25a formed at an end part of the connecting pin <NUM>, and a stopper portion 25b formed at the other end part of the connecting pin <NUM>. As shown in <FIG>, <FIG> and <FIG>, the connecting pin <NUM> is attached between/across a through hole 24b (see <FIG>) provided in the output part <NUM> and a through hole 23c (see <FIG>) provided in the input part <NUM>. Detachment of the connecting pin <NUM> from each of the input part <NUM> and the output part <NUM> is prevented by a retainer screwed member 25c attached to the screw shaft portion 25a, and by the stopper portion 25b.

In the interlocking mechanism <NUM>, if the operating lever <NUM> is pivotally operated in the front-rear direction of the vehicle body, the supporting block <NUM> pivots together with the operating lever <NUM>, and the input part <NUM> pivots following the operating lever <NUM> about the pivot axis P1 thereof as the pivot, so that power is inputted from the operating lever <NUM> by the input part <NUM>. The inputted power is transmitted to the output part <NUM> by the connecting pin <NUM>, so that the power is outputted from the output part <NUM> to the rotary operation shaft 13b. Thus, when the operating lever <NUM> is pivotally operated in the front-rear direction of the vehicle body, the rotary operation shaft 13b of the potentiometer <NUM> is rotatably operated in association with the front-rear pivoting of the operating lever <NUM>, and the potentiometer <NUM> outputs an electric signal corresponding to an operation position of the operating lever <NUM> as a detection result.

As shown in <FIG>, a damper <NUM> is connected to/between the free end side part of the input part <NUM>, and a part of the vehicle body frame <NUM> located on the rear side relative to a part of the vehicle body frame <NUM> supporting the operating lever <NUM>. The damper <NUM> is configured to act on the operating lever <NUM> via the input part <NUM> and the supporting block <NUM>. Whereby, each of the input part <NUM> and the supporting block <NUM> are utilized as a member for connecting the damper <NUM> with the operating lever <NUM>.

Claim 1:
A work vehicle comprising:
a traveling device (<NUM>, <NUM>);
a driving device (<NUM>) which drives the traveling device;
a pivot operation type operating lever (<NUM>) which performs speed change operation of the driving device;
a rotary type potentiometer (<NUM>) which detects an operation position of the operating lever;
a controlling means (<NUM>) which operates speed change of the driving device based on a detection result of the potentiometer; and
an interlocking mechanism (<NUM>) which interlocks the operating lever with a rotary operation shaft (13b) of the potentiometer;
wherein a pivot axis (P1) of the operating lever and a rotary axis (P2) of the rotary operation shaft are located on a same axis, and
wherein the interlocking mechanism includes:
an input part (<NUM>) which pivots following the operating lever about the pivot axis of the operating lever as a pivot, and inputs power of the operating lever,
an output part (<NUM>) which is supported to the rotary operation shaft of the potentiometer and outputs power of the input part to the rotary operation shaft, and
a connecting pin (<NUM>) which operably connects the input part and the output part with each other,
wherein the vehicle further comprises a damper (<NUM>) which is connected to the input part (<NUM>) and which acts on the operating lever (<NUM>), the damper (<NUM>) being connected to/between the free end side part of the input part (<NUM>), and a part of the vehicle body frame (<NUM>) located on the rear side relative to a part of the vehicle body frame (<NUM>) supporting the operating lever (<NUM>).