JPH08188060A - Working vehicle - Google Patents

Abstract

PURPOSE: To prevent damage to a hydrostatic continuously variable transmission or damage to a motor due to seizure if the motor has overrun altough vibration of the hydrostatic continuously variable transmission can be suppressed, in a working vehicle in which the shift arm of the hydrostatic continuously variable transmission is operated through the operation of a gear setting lever and via the motor. CONSTITUTION: Elastic bodies 21a, 21b, each given a certain initial stress, are interposed in a coupling member 20 which interlocks a motor M with the shift arm 7a of a hydrostatic continuously variable transmission 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle such as a riding rice transplanter or a riding lawn mower. More specifically, it operates a speed change arm of a hydrostatic stepless transmission through a motor by operating a speed setting lever. Regarding work vehicles.

[0002]

2. Description of the Related Art Conventionally, in a working vehicle such as a riding rice transplanter or a riding lawn mower, when operating a speed change arm for changing a swash plate angle of a hydrostatic continuously variable transmission through a motor by operating a speed setting lever. Is equipped with a potentiometer for detecting the operating direction and the amount of rotation of the speed setting lever, while detecting the operating direction and the amount of rotation of the speed-changing arm on the pivotal part of the speed-changing arm of the hydrostatic stepless transmission. A potentiometer is provided, and the signals from both sensors are input to the control device, and based on the deviation between the setting value of the speed setting lever and the measured value of the gearshift arm that operates the trunnion shaft, a hydrostatic stepless transmission via a motor. It is designed to operate the speed change arm.

[0003]

In the hydrostatic continuously variable transmission, pressure oil is sequentially sent out from a large number of pump side plunger groups, and a large number of motor side plunger groups are sequentially operated by this pressure oil. In order to obtain the rotation output, vibration is likely to occur due to hydraulic pulsation, and the vibration of this hydrostatic continuously variable transmission interlocks the motor and the gearshift arm of the hydrostatic continuously variable transmission. It is transmitted to the motor through the connecting rod that is, and there is play at each pivot in the connecting member,
There is an inconvenience that noise is generated due to backlash backlash in the meshing portion between the gear provided on the rotary shaft of the motor and the rack provided on the connecting member.

Further, when the motor driving the speed change arm of the hydrostatic stepless transmission is overrun, the hydrostatic stepless transmission is damaged, or an overcurrent flows to the motor to cause seizure and damage to the motor. There is a disadvantage.

Therefore, it is conceivable to support the hydrostatic continuously variable transmission in a vibration-proof manner as a means for eliminating the transmission of the vibration of the hydrostatic continuously variable transmission to the connecting member. In such a case, Even if the vibration of the hydrostatic stepless transmission can be suppressed from being transmitted to the connecting member, the hydrostatic stepless transmission is damaged when the motor overruns, or
It is not possible to prevent seizure damage to the motor, and in order to eliminate this, a separate stopper for restricting rotation of the speed change arm must be provided at the maximum rotation position of the speed change arm. There is an inconvenience that an increase in cost leads to an increase in cost and assembly is troublesome.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent damage to a hydrostatic stepless transmission or seizure of a motor when the motor overruns while suppressing vibration of a connecting member. And

[0007]

According to a first aspect of the present invention, an elastic body provided with a constant initial stress is interposed in a connecting member for interlockingly connecting a motor and a speed change arm of a hydrostatic continuously variable transmission. I am doing it.

According to a second aspect of the present invention, a linkage mechanism capable of interlocking both a speed setting lever of a hydrostatic continuously variable transmission and a speed change arm of the hydrostatic continuously variable transmission. A mounting part for mounting is provided.

[0009]

According to the first aspect of the present invention, the vibration transmitted from the hydrostatic continuously variable transmission to the motor and the overstroke when the motor overruns are caused by the elastic body interposed in the connecting member. It will be absorbed.

According to the second aspect of the present invention, when the motor fails, the connection between the motor and the speed change arm is released, and the speed setting lever is provided on the speed change lever and the speed change arm. The hydrostatic continuously variable transmission can be manually operated by linking the operation wire with the attachment portion for attaching the linkage mechanism.

[0011]

According to the first aspect of the present invention, the elastic member is interposed in the connecting member that connects the motor and the speed change arm of the hydrostatic continuously variable transmission in an interlocking manner. It is possible to prevent vibration from the transmission to the connecting member and prevent damage to the hydrostatic stepless transmission due to overrun of the motor or seizure of the motor.

According to the present invention of claim 2, when the motor fails, it can be manually operated.

[0013]

EXAMPLES Examples of the present invention will be described below for a riding rice transplanter.

As shown in FIG. 1, this riding rice transplanter is a rear-mounting riding rice transplanter equipped with a seedling planting device at the rear of the traveling machine body, and is a front wheel steering type four-wheel drive type. At the rear part of the machine body 1, a seedling planting device 4 is provided so as to be able to move up and down via a link mechanism 3 that is driven to move up and down by a hydraulic cylinder 2.

The passenger rice transplanter is transmitted from the engine to the traveling transmission in the gear transmission case 8 via the main clutch and the axially-reversible axial-hydraulic type continuously variable transmission 7 which is capable of forward and reverse rotation. Is transmitted to the front wheel differential device and the rear wheel differential device so that the front wheel 11 and the rear wheel 14 can be driven respectively. Then, the seedling planting device 4 can be driven by being transmitted to the planting mission via the inter-plant transmission device branched from the traveling transmission device and the joint shaft.

Next, the operating structure of the hydrostatic stepless transmission 7 will be described. As shown in FIG. 2, the hydrostatic stepless transmission 7 includes a speed setting lever that can be operated forward and backward. A speed setting signal from a potentiometer P ₁ attached to the pivot portion of 18 and a potentiometer P ₂ attached to the pivot portion of a sector gear 19 for detecting the operating position of the speed change arm 7a of the hydrostatic continuously variable transmission 7. Based on the feedback signal, it is driven via a control device S composed of a microcomputer and a motor M.

The sector gear 19 driven by the motor M and the shift arm 7a of the hydrostatic stepless transmission 7.
Are interlockingly connected via a connecting rod 20 which is a connecting member.

The connecting rod 20 includes an upper rod 20A on the side of the sector gear and a lower rod 20 on the side of the speed change arm 7a.
B and B are interlockingly connected to each other via a separable intermediate rod 20C, and an upper ring 2 fixed from the upper rod 20A to the bracket 20a and the intermediate rod 20C.
0c, and between the bracket 20b connected from the lower rod 20B and the ring 20d externally fitted to the intermediate rod 20C, cushion rubbers 21a and 21b as elastic bodies are interposed. And the cushion rubbers 21a, 2
The initial stress is applied to 1b by screwing the nuts 22 and 22 so that it is not elastically displaced during normal operation.

Further, when the motor M fails, the speed setting lever 18 and the static pressure type hydraulic speed control lever 18 can be operated so that the speed change arm 7a of the static hydraulic pressure type continuously variable transmission 7 can be operated via the speed setting lever 18. Gear shifting arm 7a of the gear shifting device 7
And the release wire 23 as a linking mechanism for both
Arms 24 and 25 as mounting portions capable of interlocking connection via a and 23b are provided, and wire receivers 26 and 27 are provided in advance. The mounting portion 25 on the side of the speed changing arm 7a is the speed changing arm 7a itself. It is composed by. Therefore, when the motor M fails, the lower rod 20B is removed from the speed change arm 7a and the speed change arm 7a is removed.
The release wires 23a and 23b are connected to the arm 24 of the speed setting lever 18 as shown by a virtual line in FIG.

According to the above structure, when the speed setting lever 18 is operated to the forward side, the sector gear 19 rotates clockwise, and the speed change arm 7a of the hydrostatic continuously variable transmission 7 rotates counterclockwise. Will be done. In such a case, the push-up force from the lower portion due to the vibration of the hydrostatic continuously variable transmission 7 is absorbed by the elastic displacement of the upper cushion rubber 21a, and the pulling force to the lower portion is absorbed by the elastic displacement of the lower cushion rubber 21b. It Then, the overstroke of the sector gear 19 when the motor M overruns is absorbed by the elastic displacement of the upper cushion rubber 21a.

The push-up force from the lower portion and the pulling force to the lower portion due to the vibration of the hydrostatic continuously variable transmission 7 when the speed setting lever 18 is operated to the reverse side are the same as those in the forward shift. It is absorbed by the elastic displacement of the upper cushion rubber 21a and the elastic displacement of the lower cushion rubber 21b. Further, the motor M absorbs the overstroke of the overrunning sector gear 19 by the elastic displacement of the lower cushion rubber 21b.

[Other Embodiments] As the elastic body, a resin other than rubber may be used as long as it can absorb minute vibrations.

The connecting member may be a link mechanism other than the rod.

The work vehicle may be a riding lawn mower or a tractor as long as it has a hydrostatic continuously variable transmission.

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

[Brief description of drawings]

[Fig. 1] Overall side view of passenger rice transplanter

FIG. 2 is a schematic view showing a linkage between a speed setting lever and a hydrostatic continuously variable transmission.

[Explanation of symbols]

 7 hydrostatic stepless transmission 7a speed change arm 18 speed setting lever 20 connecting member 21a elastic body 21b elastic body 23a linkage mechanism 23b linkage mechanism 24 mounting portion 25 mounting portion M motor

Claims (2)

[Claims] 1. A work vehicle in which a speed change lever (18) is operated to operate a speed change arm (7a) of a hydrostatic continuously variable transmission (7) via a motor (M). Elastic bodies (21a) and (21b) having a certain initial stress applied to a connecting member (20) interlockingly connecting with the speed change arm (7a) of the hydrostatic continuously variable transmission (7) are interposed. Work vehicle. 2. A speed setting lever (18) of the hydrostatic stepless transmission (7) and the hydrostatic stepless transmission (7).
2. The speed change arm (7a) is provided with attachment parts (24), (25) for attaching linkage mechanisms (23a), (23b) capable of interlocking the two, respectively. Work vehicle.