JP2005119466A - Running transmission for working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a running transmission which decides the opening degree of an engine throttle valve corresponding to the tread of a gear shift pedal 3 by using the running transmission provided with an interlock mechanism capable of adjusting the neutral position of a hydraulic stepless transmission to the gear shift pedal 3. <P>SOLUTION: The forward/backward pedals 3F, 3R are interlocked with the speed change shaft 32 of the HST via a connecting member 30, one end of a push rod 34 is provided to the neutral arm 27 for neutral and returning of an engine output adjustment mechanism G, and a counter arm 35 is connected to the other end of the push rod 34. Since the other end of the counter arm 35 is connected to the acceleration arm 46 of the engine throttle, the engine throttle opening degree is decided corresponding to the tread of the forward pedal 3F or the backward pedal 3R. When the tread of the forward pedal 3F or the backward pedal 3R is released, the engine is brought into an idling state by the neutral automatic return mechanism N, returning the HST to the neutral position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a traveling transmission such as a tractor, and can also be used for a seedling planter or a transporter that performs traveling transmission using a hydraulic continuously variable transmission.

  A tractor travel transmission using a hydraulic continuously variable transmission (HST) has a neutral position locking mechanism for locking the neutral position of the transmission, and the shift pedal position is set at the neutral position of the hydraulic continuously variable transmission. When adjusted, the shift pedal position often moves, and the operation feeling of the pedal tends to be different.

Therefore, this shift is achieved by adjusting the length between the shift operation shaft (trunion shaft) of the HST and the shift pedal having the neutral locking mechanism so that the neutral position of the HST can be adjusted without moving the operation position of the shift pedal. A traveling transmission such as a tractor provided with an interlocking mechanism capable of adjusting the neutral position of the hydraulic continuously variable transmission HST with respect to a pedal is known.
JP 7-89363 A

The conventional traveling transmission apparatus is configured so that when the shift pedal is depressed, the depressing pedal immediately returns to the neutral position.
On the other hand, in a tractor equipped with the conventional HST transmission, the work is usually performed with a full throttle, so that the full throttle consumes a lot of fuel for moving in a garage, indoors, narrow roads, etc. Also, the noise is loud.

  When the opening degree of the engine throttle valve (governor) is determined in accordance with the depression amount of the shift pedal, the operation or traveling can be performed without driving the engine in the full throttle state.

  In view of this, the present invention provides an engine throttle valve according to the depression amount of the shift pedal using a traveling transmission provided with an interlocking mechanism capable of adjusting the neutral position of the hydraulic continuously variable transmission with respect to the shift pedal described in the prior art. It is to obtain a configuration in which the opening degree is determined.

The above-mentioned problem of the present invention is solved by the following solution means.
According to the first aspect of the present invention, the speed change operation shaft 32 of the hydraulic continuously variable transmission and the speed change operation shaft 32 of the hydraulic continuously variable transmission are rotationally operated, and the rotational output thereof is shifted forward or backward to change the speed in the forward or reverse direction. The shift pedals 3F and 3R, the neutral automatic return mechanism N that automatically returns the shift pedals 3F and 3R and the shift operation shaft 32 to the neutral position after the operation of the shift pedals 3F and 3R, and the shift pedals 3F and 3R This is a travel transmission device for a work vehicle that includes a forward or reverse operation amount and an engine output adjustment mechanism G that changes the engine output in conjunction with the neutral automatic return mechanism N.

  According to a second aspect of the present invention, the engine output adjusting mechanism G includes an accelerator arm 46 that increases or decreases the engine output. The first wire member 36 connects the arm 46 and the movable portion of the neutral automatic return mechanism N. 2. The travel transmission device for a work vehicle according to claim 1, wherein the arm 46 and a throttle lever 47 that is provided on the vehicle and can hold an operation position are connected via a second wire member 31. .

  One end of the push rod 34 is provided on the neutral return arm 27 for neutralization of the engine output adjustment mechanism, and the other end of the push rod 34 is linked to the HST speed change operation shaft 32 via the connecting member 30 and the forward / reverse pedals 3F, 3R. Since the counter arm 35 is connected to the other end of the counter arm 35 and the other end of the counter arm 35 is connected to the accelerator arm 46 of the engine throttle, the engine throttle opening is determined according to the amount of depression of the HST forward pedal 3F or the reverse pedal 3R.

  Further, when the HST forward pedal 3F or the reverse pedal 3R is released, the engine E is in an idling state by the neutral automatic return mechanism N, and the HST also returns to the neutral position.

  Since the engine throttle opening is changed according to the depression amount of the HST forward pedal 3F or the reverse pedal 3R, fuel efficiency is good.

FIG. 1 is a side view of a tractor according to an embodiment of the present invention, and FIG. 2 is a transmission configuration diagram of the tractor of FIG.
The tractor vehicle body 5 is connected from the front engine E to the clutch housing 6, the HST case 7 and the rear transmission case 8 to be integrated, and the front front axle bracket 9 can be steered by a steering handle 10. The rear wheel 12 is mounted on the front end of the rear axle housing on both the left and right sides of the rear transmission case 8, and the front and rear wheels 11 and 12 are driven to drive. A pilot seat 14 is provided on the seat floor between the left and right fenders 13 on the mission case 8.

  A lift arm 15 provided in a hydraulic case on the transmission case 8 so as to be movable up and down is connected by a left and right lower link 16 and a lift rod 17, and a work machine connected to the rear ends of the lower link 16 and the top link is provided. You can go up and down. An engine E is mounted in the bonnet 18, and the hydraulic continuously variable transmission (HST) is provided in the HST case 7, and passes through the main clutch 54 (FIG. 2) in the clutch housing 6, and the HST input shaft. 19 (FIG. 2), the forward operation F from the neutral N position by the speed change operation shaft 32 (FIG. 3), the reverse R, and the interlocking by these continuously variable transmissions, the interlock to the sub-transmission device 21, The differential gear mechanism of the rear wheel 12 and the output shaft to the front wheel 11 are transmitted. In the hydraulic continuously variable transmission, the swash plate angle of the variable displacement pump P shown in FIG. 2 is changed, and the rotation of the output shaft by the fixed displacement motor M is continuously variable.

  In FIG. 2, a hydraulic continuously variable transmission having a variable displacement pump P and a variable displacement motor M is used as a traveling transmission device with a transmission structure of an agricultural tractor, having a subtransmission device 21 with two stages of high and low, and a variable displacement pump P and a variable displacement motor M. It was. Further, before driving the HST input shaft 19 from the main clutch 54, the power extracted by branching the PTO input shaft 56 is taken out to the PTO shaft 55 via the PTO transmission 57.

  The hydraulic continuously variable transmission has a variable displacement pump P and a variable displacement motor M in a closed hydraulic circuit 50, and adjusts the swash plate angle of the variable displacement pump P by depressing a shift pedal, The input rotation of the input shaft 19 can be decelerated continuously variable to the output rotation of the HST output shaft 53, and can be continuously switched by switching between forward and reverse.

  The power from the HST output shaft 53 is taken out by the travel shaft 58, and power is transmitted from the travel shaft 58 to the differential device 59 for transmission to the rear wheel 12, the front wheel transmission shaft 60, and the differential device 61 for transmission to the front wheel 11. It is taken out. A four-wheel drive four-wheel drive clutch gear 62 for turning on and off the transmission of the front wheel transmission shaft 60 is provided between the PTO input shaft 56 and the front wheel drive shaft 60.

  FIG. 3 shows a side view of the shift pedal portion, and FIG. 4 shows a plan view of the shift pedal portion. A shift operation shaft 32 interlocking with the HST input shaft 19 is projected on the right side surface of the HST case 7, and the shift arm 22 rotates integrally with the tip of the shift operation shaft 32 around the shift operation shaft 32. It is provided freely. One end of a counter 23 is rotatably connected to the end 22a of the speed change arm 22 via an arm 24, and the other end 22b of the speed change arm 22 is a turnbuckle type in a free state that is not fixed to the HST case 7. One end of the connecting member 30 is rotatably connected. The other end of the connecting member 30 is rotatably connected to an intermediate portion of the forward pedal arm 3Fa. Further, the end portion of the counter 23 opposite to the connection portion with the speed change arm 22 is rotatably connected to the tip portion of the arm 25 fixed to the outer peripheral cylindrical body 4 b of the pedal shaft 4. A cylindrical body 4a and a cylindrical body 4b are rotatably inserted in parallel to the pedal shaft 4 on the outer periphery of the pedal shaft 4, and the forward pedal arm 3Fa and the reverse pedal arm 3Ra are fixed to each other.

  Further, the cylindrical portion 27a of the neutral arm 27 is in contact with the concave portion 3Faa provided on the side surface opposite to the side surface on the pedal shaft 4 side of the forward pedal arm 3Fa so that the cylindrical portion 27a of the neutral arm 27 is fitted. One end of a turnbuckle type connecting member 30 is provided in the middle of the forward pedal arm 3Fa, and the other end of the connecting member 30 is rotatably connected to an end portion 22b of the speed change arm 22.

  The neutral arm 27 is substantially T-shaped in a side view, and the cylindrical portion 27a swings around a rotation shaft 27b of the neutral arm 27 located on the left side of FIG. A neutral spring 28 is locked to the tip of the neutral arm 27 opposite to the cylindrical portion 27a, and the cylindrical portion 27a is always urged upward.

  When the forward pedal arm 3Fa is stepped on due to the structure of the shift pedal portion, the connecting member 30 is pulled toward the arm 3Fa and moves in the direction of arrow A, and the end 22b of the shift arm 22 rotates in the clockwise direction. As the arm 22 rotates, the trunnion shaft 32 integral with the transmission arm 22 rotates in the direction of arrow A, and the swash plate of the hydraulic pump P of the HST is tilted in the direction in which the forward drive force is generated. At this time, the cylindrical portion 27a of the neutral arm 27 is disengaged from the concave portion 3Faa of the forward pedal arm 3Fa.

  When the reverse pedal arm 3Ra is depressed, the arm 25 integral with the cylindrical body 4b of the pedal shaft 4 rotates clockwise, and the counter 23 moves in conjunction with this, and the speed change arm 22 moves counterclockwise in the direction of arrow B. The transmission operation shaft 32 rotates in the direction of arrow B, and the swash plate of the HST hydraulic pump P is tilted in the direction in which the reverse drive force is generated.

  At this time, the forward pedal arm 3Ra moves in the direction in which the connecting member 30 is lifted in conjunction with the movement of the speed change arm 22 in the arrow B direction, so that the cylindrical portion 27a of the neutral arm 27 is disengaged from the concave portion 3Faa of the forward pedal arm 3Fa. .

  When the forward pedal 3F or the reverse pedal 3R is released, the neutral arm 27 is urged counterclockwise by the spring 28 about the rotation shaft 27b, so that the cylindrical portion 27a of the neutral arm 27 is moved forward. The shifting operation shaft 32 returns to the neutral position by moving into the recess 3Faa of 3Fa.

  For some reason, when an error occurs between the neutral N position by the neutral locking mechanism and the neutral position of the HST speed change operation shaft 32, for example, the shift pedals 3F and 3R have the cylindrical portion 27a in the recess 3Faa of the forward pedal 3Fa. When the HST output shaft 53 (FIG. 2) rotates at a speed despite the fitted neutral position, the turnbuckle system that connects the reverse pedal 3R and the transmission arm 22 is connected. By adjusting the length of the connecting member 30, the neutral position of the shift pedal 3F, 3R can be returned to a predetermined position, and at the same time, the neutral position of the HST speed change operation shaft 32 can be adjusted.

  Further, one end of the push rod 34 is locked to the end of the T-shaped portion opposite to the end of the T-shaped portion where the neutral spring 28 of the neutral arm 27 is locked, and the end of the push rod 34 is locked to the end of the counter arm 35. The other end is connected. The other end of the counter arm 35 that rotates about the center fulcrum 35a is connected to the end of the cable 36, and the tip of the cable 36 is connected to the accelerator arm 46 of the engine throttle. Thus, the push rod 34 is actuated by depressing the speed change pedals 3F, 3R, and the driving force of the engine E is adjusted, and the wheel drive output shaft is rotated at a higher speed as the depressing amounts of the forward pedal 3F and the reverse pedal 3R are larger.

  Further, the accelerator arm 46 is rotated by the wire 31 according to the operation of the throttle lever 47. A lever holding mechanism 47a is provided at the base of the throttle lever 47 so that the lever is held at a position after the operation of the throttle lever 47. Therefore, the position of the engine governor (output adjustment mechanism) G and the opening of the throttle valve are controlled by the lever. Maintain a state corresponding to the later position.

  Accordingly, the engine output can be further increased by starting to depress the speed change pedals 3F and 3R from the engine output state corresponding to the position after the throttle lever 47 is operated.

  According to the present embodiment, in the shaft configuration in which the forward / reverse pedals 3F and 3R are linked to the HST speed change operation shaft (trunnion shaft) 32 via the connecting member 30 and the like to control the HST, One end of the push rod 34 is provided, and a counter arm 35 is connected to the other end of the push rod 34. The other end of the counter arm 35 is connected to the accelerator arm of the engine throttle, so the HST forward pedal 3F or the reverse pedal 3R. Since the engine throttle opening is determined according to the amount of depression of the engine, fuel efficiency is good. At the time of work, it is possible to work at full throttle by operating the throttle lever that is normally provided in the tractor.

  Another embodiment of the present invention is shown in the schematic side view of the pedal portion of FIG. As shown in FIG. 5, a cam plate 37 is provided on the pedal shaft 4 to which the HST forward pedal arm 3Fa and the reverse pedal arm 3Ra are fixedly connected instead of the neutral return neutral arm 27, and the cam plate 37 has a recess 37a. The cylindrical portion 27a of the neutral arm 27 is fitted, one end of each of the rods 34a, 34b is connected to the tip of both wings of the cam plate 37, and the other end of the rod 34a, 34b is connected to one end of the cables 36a, 36b. Further, an accelerator arm 46 of the engine throttle may be connected to the other end of the cables 36a and 36b.

  The configuration shown in FIG. 5 has good fuel efficiency because the engine throttle opening is determined in accordance with the amount of depression of the HST forward pedal 3F or the reverse pedal 3R as in the configurations shown in FIGS.

  Further, the embodiment shown in the side view of the shift pedal portion of FIG. 6 has a configuration in which an inward expansion type brake 39 and its case 40 are provided on the same shaft as the HST pedal shaft 4 to easily provide an auto cruise function. .

  A case 40 of the brake 39 is provided on the extension of the HST pedal shaft 4, and an inward expansion type brake 39 is provided on the same shaft as the pedal shaft 4, and the brake 39 is locked to lock the HST pedal 3 (3F, 3R ) Stop the stepping position to make a stepless auto cruise. For this purpose, the front end portion of the auto cruise lever 41 is rotatably supported in the inner expansion brake case 40, and when the auto cruise lever 41 is pulled to the body near the other end of the auto cruise lever 41, the end of the lever A lever locking member 42 is provided for locking.

  When the HST pedal 3 (3F, 3R) is depressed and the auto cruise lever 41 is tilted and the lever 41 is locked to the lever locking member 42 and fixed at an arbitrary speed, the cruise state is established. Further, the cruise state can be canceled by removing the auto cruise lever 41 from the lever locking member 42.

  The conventional shoe lining fixed auto-cruise device has a very large operating force and is difficult to operate and it is difficult to obtain an appropriate speed. However, in the above configuration, auto-cruise can be set at an arbitrary speed, and the configuration is relatively Simple.

Another embodiment in which the output of the HST from the motor output shaft 53 (or HST) can be adjusted according to the depression amount of the HST shift pedal 3 will be described.
FIG. 7 shows a configuration diagram in which the accelerator arm 46 of the engine E moves in conjunction with the depression angle of the HST pedal 3. The depression speed is detected from the depression angle of the HST pedal 3 and the HST trunnion shaft 32 is moved. A configuration in which the tilt angle is controlled by the step motor 43 is employed.

  The potentiometer 44 senses the depression angle of the HST pedal 3, detects the depression speed, the controller 70 controls the amount of movement of the HST trunnion shaft 32 using the step motor 43, and simultaneously controls the accelerator arm 46 of the engine E. The amount of operation is calculated, and the engine output is controlled by adjusting the opening of the throttle valve of the engine E by the step motor 45 provided on the engine side.

  Alternatively, the engine rotation may be controlled in conjunction with the amount of depression of the HST pedal 3 by controlling the inclination angle of the accelerator arm 46 with the step motor 45 on the engine side.

  Further, according to the depression angle of the HST pedal 3, an equalizer link 48 is provided between the throttle lever 47 and the accelerator arm 46, and the driving amount of the step motor 45 on the engine side is interlocked with the equalizer link 48. good. In this case, the engine speed is controlled by a manual operation by the throttle lever 47 and an automatic operation by the step motor 45 on the engine side in conjunction with the depression amount of the HST pedal 3.

  Further, in the configuration using the HST shift pedal 3, a neutral restriction link configuration such as a connecting member 30 that always returns the shift pedal position to the “neutral” position after the pedal is depressed is required. By providing the potentiometer 44 between the connecting member 30 and the shift pedal 3, the amount of pedal depression can be detected.

  Further, in addition to providing the stepping angle detection potentiometer 44 of the speed change pedal 3 at a portion where the connecting member 30 is provided, the pedal 3 pivot fulcrum, the accelerator arm 46 pivot fulcrum, and the neutral arm 27 pivot fulcrum. You may attach to.

  In addition, a cruise lever operation amount detection potentiometer 49 is provided at the base of the cruise lever 41, and when the shift pedal operation or the brake operation is performed during the operation at the traveling control speed by the cruise lever position, the potentiometer 44 detects and gives priority. A controller 70 having an arithmetic function for determining the circuit by the controller 70 and releasing the operation control of the cruise lever 41 may be provided.

  Further, an engine speed sensor 38 is provided in the engine E, and the controller 70 controls to “decrease the vehicle speed” when the engine speed decreases based on the engine speed detected by the sensor 38. It is also possible to adopt a configuration in which the control of the engine throttle valve is controlled (load control) by the HST pedal 3 by the calculation of the controller 70 in accordance with the engine rotation fluctuation.

  Thus, the engine operability by the shift pedal 3 can be improved.

  The present invention relates to a traveling transmission such as a tractor, and can also be used for a seedling transplanter, a transporter, or the like that performs traveling transmission using a hydraulic continuously variable transmission.

It is a side view of the tractor of the Example of this invention. It is a transmission block diagram of the tractor of FIG. It is a side view of the speed-change pedal part of the tractor of FIG. It is a top view of the speed-change pedal part of the tractor of FIG. It is a side view of the speed-change pedal part of the modification of the tractor of FIG. It is a side view of the speed-change pedal part of the modification of the tractor of FIG. It is a block diagram of a speed change pedal, an engine part, etc. of the modification of the tractor of FIG.

Explanation of symbols

3F Forward pedal 3Fa Forward pedal arm 3Faa Recess 3R Reverse pedal 3Ra Reverse pedal arm 4 Pedal shaft 4a, 4b Outer cylindrical body 5 Car body 6 Clutch housing 7 HST case 8 Mission case 9 Front axle bracket 10 Steering handle 11 Front wheel 12 Rear wheel 13 Left and right Fender 14 Pilot seat 15 Lift arm 16 Lower link 17 Lift rod 18 Bonnet 19 HST input shaft 22 Shifting arm 23 Counter 24, 25 Arm 27 Neutral arm 27a Cylindrical portion 27b Rotating shaft 28 Neutral spring 30 Connecting member 31 Wire 32 Shifting operation shaft 34 Push rod 35 Counter arm 35a Support point 36 Cable 37 Cam plate 37a Recess 38 Engine speed sensor 39 Brake 40 Case 4 Auto cruise lever 42 Lever locking member 43 Step motor 44 Potentiometer 45 Step motor 46 Accelerator arm 47 Throttle lever 48 Equalizer link 49 Potentiometer 50 Closed hydraulic circuit 53 HST output shaft 54 Main clutch 55 PTO shaft 56 PTO input shaft 57 PTO transmission 58 Traveling shaft 59 Differential device 60 Front wheel transmission shaft 61 Differential device 62 Four-wheel drive clutch gear 63 Shift lever 70 Controller

Claims (2)

A speed change operation shaft (32) of the hydraulic continuously variable transmission;
A forward / reverse speed change pedal (3F, 3R) for rotating the speed change operation shaft (32) of the hydraulic continuously variable transmission and changing the speed of the rotation output in the forward or reverse direction;
A neutral automatic return mechanism (N) for automatically returning the shift pedal (3F, 3R) and the shift operation shaft (32) to the neutral position after the operation of the shift pedal (3F, 3R);
A work vehicle comprising an engine output adjusting mechanism (G) that changes an engine output in conjunction with a forward or reverse operation amount of the shift pedal (3F, 3R) and an automatic neutral return mechanism (N). Traveling transmission.   The engine output adjustment mechanism (G) includes an accelerator arm (46) for increasing or decreasing the engine output. The arm (46) and a movable part of the neutral automatic return mechanism (N) are connected to a first wire member ( 36), and the arm (46) and a throttle lever (47) provided on the vehicle and capable of holding the operation position are connected via a second wire member (31). Item 2. A travel transmission device for a work vehicle according to Item 1.

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