Transmission of work vehicle

Abstract

To provide a work vehicle operable when shifting is performed for a hydraulic continuously variable transmission by a foot pedal and configured to strengthen the linkage between the foot pedal and the hydraulic continuously variable transmission.SOLUTION: In a work vehicle in which a hydro-static transmission (HST) pedal 9 for shifting the rotation of an HST 4 mounted in a mission case 3 configured to change output rotation of an engine 2 is disposed on a floor 8, an HST pivot shaft 20 and a brake pivot shaft 21 are horizontally supported by an operation box 30 attached to the HST 4. The HST pivot shaft 20 and the brake pivot shaft 21 are connected by a reinforcement frame 25 from a flange 22 on the HST 4 side.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a continuously variable transmission operating device for a work vehicle that changes the travel speed by using a hydrostatic continuously variable transmission. [Background technology]

[0002] 2. Description of the Related Art Work vehicles such as agricultural vehicles and civil engineering vehicles are adapted to travel at a speed suitable for the work being carried out by repeatedly moving forward and backward in a work site and changing the travel speed.

[0003] For example, in Japanese Patent Application Laid-Open No. 2004-28309, a hydrostatic continuously variable transmission (hereinafter referred to as HST) is provided with forward and reverse pedals that are operated by foot to change the speed, and the forward and reverse travel speeds are changed by steering. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-28309 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to change gears in the above-mentioned work vehicles by stepping on the pedal, the foot pedal, which may be pressed down hard, must be firmly connected to the hydraulic variable speed transmission.

[0006] To provide a work vehicle in which a hydraulic continuously variable transmission is operated by changing the speed with a foot pedal, the object of the present invention being to strengthen the interlocking between the foot pedal and the hydraulic continuously variable transmission. [Means for solving the problem]

[0007] The above object of the present invention can be achieved by the following technical means.

[0008] The invention of claim 1 relates to a transmission device for a work vehicle, characterized in that in a work vehicle in which an HST pedal 9 for changing the rotation of an HST 4 provided on a floor 8 is provided in a transmission case 3 which changes the output rotation of an engine 2, an HST pivot shaft 20 and a brake pivot shaft 21 are supported horizontally on an operation box 30 attached to the HST 4, and the HST pivot shaft 20 and the brake pivot shaft 21 are connected to a flange 22 on the HST 4 side by a reinforcing frame 25.

[0009] The invention of claim 2 provides a transmission for a work vehicle according to claim 1, characterized in that a lower frame 26 is provided below the reinforcing frame 25 to guard the bottom side.

[0010] The invention of claim 3 is the transmission for the work vehicle of claim 2, in which oil supply nipples 20 a, 21 a are provided on the HST pivot shaft 20 and the brake pivot shaft 21 at the upper part of the lower frame 26. Effect of the Invention

[0011] In the invention of claim 1, the HST pivot shaft 20 and the brake pivot shaft 21, which are subjected to strong bending forces when the operator aboard the work vehicle depresses the gear change pedal or brake pedal, are firmly supported on the operation box 30 by a reinforcing frame 25 provided on the flange 22 on the HST 4 side, so that gear changes are reliable even if the HST pedal 9 is roughly depressed and operated.

[0012] In the invention of claim 2, the HST pivot shaft 20 and the brake pivot shaft 21 are firmly supported by the lower frame 26 together with the reinforcing frame 25, and even if a stone hits the bottom, the lower frame 26 prevents damage to the HST pivot shaft 20 and the brake pivot shaft 21.

[0013] In the invention of claim 3, the oil supply nipples 20a, 21a provided on the HST pivot shaft 20 and the brake pivot shaft 21 are protected by the lower frame 26 and are not damaged, and oil can be supplied from the side of the lower frame 26. [Brief description of the drawings]

[0014] [Figure 1]FIG. 2 is a right side view of the work vehicle according to the embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. 2 is a perspective view of an operation box of the work vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a side view of a tractor shown as an example of a work vehicle, and Fig. 2 is a plan view of the tractor.

[0016] A conventionally known tractor 1 is equipped with an engine 2 at the front of the machine body, and the rotational power of this engine 2 is transmitted to a hydrostatic continuously variable transmission (HST) 4 attached to the front of a transmission case 3 via a universal joint 5. The power input to the HST 4 changes the inclination angle of the pump-side swash plate via a trunnion shaft according to the amount of depression of an HST pedal 9 (forward pedal 9a and reverse pedal 9b) provided on the right side of a floor 8 (the right side when facing forward), thereby controlling the rotation speed and direction of the motor shaft. In other words, when the HST forward pedal 9a is depressed with the toe, the machine moves forward, and when the HST reverse pedal 9b is depressed with the heel, the machine moves backward, and in either case, the traveling speed increases or decreases according to the amount of depression.

[0017] The transmission case 3 is provided with an HST 4, and rotational power reduced by an internal reduction mechanism in the HST 4 is transmitted to left and right rear wheels 10, 10. A front-wheel drive shaft 12 for driving the front wheels 11, 11 is journalled at the front of the transmission case 3.

[0018] A brake pedal 7 is provided on the left side of the floor 8 (the left side when facing the forward direction), and when the brakes are applied to the left and right rear wheels 10, 10 and the front wheels 11, 11, the brakes are applied to the left and right rear wheels 10, 10 and the front wheels 11, 11.

[0019] 3 and 4 show the bottom of the vehicle body, with the flange 22 of the HST 4 and the front flange 23 on the front chassis side connected by a right frame 28 and a left frame 29, and the speed change shaft cylinder 20 that journals the HST pedal 9 and the brake cylinder 21 that journals the brake pedal 7 are hung horizontally between the left and right frames 28, 29 to form an operation box 30. The speed change shaft cylinder 20 and the brake cylinder 21 are connected by a reinforcing frame 25 that connects to the flange 22, and the bottom side is connected to a lower frame 26 so as to cover the oil supply nipple 20a of the speed change shaft cylinder 20 and the oil supply nipple 21a of the brake cylinder 21.

[0020] At the rear of the vehicle body, a hydraulic cylinder case 15 is attached to the upper rear part of the transmission case 3, and lift arms 16, 16 are rotatably pivoted on both the left and right sides of this hydraulic cylinder case 15. Lift rods 18, 18 are provided between the lift arms 16, 16 and the lower links 17, 17, and a working machine is connected to the rear ends of the top link 13 and the lower links 17, 17, so that when the lift arms 16, 16 are rotated, the working machine (not shown) is raised and lowered.

[0021] HST4 generally uses hydraulic transmission to change the speed of the trunnion shaft hydraulically, but if a geared motor that uses a speed change gear to change the speed of the trunnion shaft is used, the consumption of drive hydraulic pressure can be reduced and energy can be saved. Also, if a dedent mechanism for returning to neutral is provided on the trunnion drive shaft, the HST4 will return to neutral in the event of an engine stall, reducing the driving force when restarting, making it easier to restart the engine.

[0022] Furthermore, when reversing the HST4, the pedal is controlled to prevent sudden acceleration, ensuring a gradual reverse motion of the vehicle, making it safer. [Explanation of symbols]

[0023] 8th Floor 9 HST Pedal 20 HST pivot shaft 20a Oil Nipple 21 Brake pivot shaft 21a Oil nipple 22 Flange 25 Reinforcement frame 26 Lower Frame 30 Operation Box

Claims

1. In a work vehicle having an HST pedal (9) mounted on the floor (8) for changing the rotation of an HST (4) mounted on a transmission case (3) which changes the output rotation of an engine (2), an HST pivot shaft (20) and a brake pivot shaft (21) are supported horizontally on an operation box (30) attached to the HST (4), and the HST pivot shaft (20) and the brake pivot shaft (21) are connected to a flange (22) on the HST (4) side by a reinforcing frame (25).

2. 2. A transmission for a work vehicle according to claim 1, further comprising a lower frame (26) provided below the reinforcing frame (25) for guarding the bottom side.

3. 3. A transmission for a work vehicle according to claim 2, wherein oil supply nipples (20a, 21a) are provided on the HST pivot shaft (20) and the brake pivot shaft (21) at an upper portion of the lower frame (26).

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