JP2011110984A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for correctly detecting movement of forward/backward gear shift pedals and accurately controlling a travelling speed. <P>SOLUTION: In the working vehicle, movement of the forward gear shift pedal 3 and the backward gear shift pedal 4 for moving a machine back and forward is converted into rotation of a sensor arm 68 and the rotation of the sensor arm 68 is detected by a gear shift sensor 5 and the travelling speed is changed by rotating a trunnion shaft 7 of a hydraulic continuously variable transmission 6 by an actuator 8 corresponding to a detection signal of the transmission sensor 5. The working vehicle has a structure for returning the position of the sensor arm 68 to a neutral position by an energizing force of a torsion spring 9 arranged for a pivot shaft 66 of the sensor arm 68. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a work vehicle. In particular, the present invention relates to a transmission operation device for a transmission with a hydraulic continuously variable transmission used in a hydraulically driven vehicle such as a tractor.

  In hydraulically driven vehicles such as agricultural tractors, a forward pedal that moves the vehicle in the forward direction and a reverse pedal that moves backward are arranged side by side on the floor panel of the cockpit, and the driver depresses the forward or reverse pedal as appropriate. There are a configuration in which the vehicle is moved forward and backward, and a configuration in which the vehicle is moved forward or backward by depressing one shift pedal back and forth. For example, Japanese Patent Application Laid-Open No. 2005-233260 discloses a shift pedal and a hydraulic continuously variable transmission device in which a forward speed is increased when a shift pedal provided on a step is stepped forward, and a reverse speed is increased when the shift pedal is stepped backward. The interlocking structure of the speed change operation shaft is described.

JP 2005-233260 A

  In the shift operation device of the hydraulically driven vehicle, the shift operation shaft of the hydraulic continuously variable transmission is not directly rotated by the forward / reverse shift pedal, but the shift operation shaft is detected according to the movement of the shift pedal. However, in this configuration, it is necessary to control the hydraulic cylinder by accurately detecting the movement of the shift pedal.

  It is an object of the present invention to provide a speed change operation device for a hydraulically driven vehicle that accurately detects the movement of a speed change pedal and accurately controls the traveling speed.

The problems of the present invention are solved by the following technical means.
According to the first aspect of the present invention, the movement of the forward shift pedal 3 and the reverse shift pedal 4 for moving the vehicle forward and backward is converted into the rotation of the sensor arm 68, and the rotation of the sensor arm 68 is detected by the shift sensor 5. In a working vehicle in which the trunnion shaft 7 of the hydraulic continuously variable transmission 6 is rotated by the actuator 8 in accordance with the detection signal of the transmission sensor 5 to change the traveling speed, the torsion spring provided on the pivot shaft 66 of the sensor arm 68. The work vehicle is configured to return the position of the sensor arm 68 to the neutral position with an urging force of 9.

  When the foot is released from the forward shift pedal 3 and the reverse shift pedal 4, the sensor arm 68 returns to the neutral position by the resilient force of the torsion spring 9, which is detected by the shift sensor 5 and actuates the actuator 8 to make the hydraulic stepless. The trunnion shaft 7 of the transmission 6 is returned to the neutral position, and traveling is stopped. At this time, since the torsion spring 9 directly returns the sensor arm 68 to the neutral position, the sensor arm 68 is surely brought to the neutral position as compared with the configuration in which the return spring is provided in the middle of the interlocking of the shift pedals 3 and 4 and the sensor arm 68. There is a returning action, and the speed control by the speed change pedals 3 and 4 can be accurately performed.

It is a top view of a hydraulic drive vehicle (tractor). It is a side view of a hydraulic drive vehicle (tractor). It is a sectional side view of a mission case. It is a partially expanded side view of a hydraulic drive vehicle (tractor). FIG. 2 is a partially enlarged plan view of a hydraulically driven vehicle (tractor). It is an enlarged side view of a speed change pedal. It is an enlarged plan view of a transmission pedal. It is a partial side view which shows the action state of a speed change pedal. It is a partial side view which shows the action state of a speed change pedal. It is an enlarged side view of a transmission mechanism. It is an expansion perspective view of a transmission mechanism. Part of hydraulic circuit diagram for auto cruise (constant speed) Some hydraulic circuit diagrams when using a manual switching valve

Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 and FIG. 2 are drawings showing the entirety of a tractor which is an embodiment of a hydraulically driven vehicle, and a vehicle body is constituted by a prime mover 11 on which an engine 10 on the front side of the fuselage is mounted and a transmission case 1 extending rearward from the prime mover 11. The floor panel 2 is mounted on the transmission case 1 via the cushioning material k, and a cockpit seat 12 on which an operator gets on the rear side of the floor panel 2 is provided. The front wheel 14 and the rear wheel 15 are mounted on a drive shaft that protrudes left and right from the mission case 1 at the bottom.

  A forward / reverse lever 16 is provided on the right side of the steering handle 13, a forward pedal 3 and a reverse pedal 4 are provided on the right side of the floor panel 2, and a clutch pedal (not shown) and a brake pedal (not shown) are provided on the left side of the floor panel 2. ). The floor panel 2 is attached to the upper side of the mission case 1 with a cushioning material k such as a mount rubber, and the left and right central portions are formed to rise forward along the shape of the mission case 1. Horizontal sub-floor panels 94 and 95 are overhanged and integrally attached to the left and right sides of the floor panel 2.

  Although not shown, on the left side of the cockpit 12, a PTO clutch lever for intermittently driving a PTO output shaft for driving a work gear such as a main gear shift lever for changing a traveling gear stage and a rotary mounted on the rear portion of the machine body, etc. Is provided.

Next, the power transmission mechanism in the mission case 1 will be described with reference to FIG.
The transmission case 1 that increases and decelerates the output of the engine 10 to the front wheel 14, the rear wheel 15, the rear PTO output shaft 42, and the intermediate PTO output shaft 43 is transmitted in three hollows: a front case 17, an intermediate case 18, and a rear case 19. It is a hollow case in which the cases are connected together.

  An input shaft 21 that is spline-fitted to a coupling 51 that is connected to the output shaft 20 of the engine 10 in the front case 17 is connected to an input shaft 52 of a hydraulic continuously variable transmission (hereinafter referred to as “HST”) 22 to generate power. Be transmitted.

  The HST 6 includes a variable displacement hydraulic pump 53 and a fixed displacement hydraulic motor 54, and changes the rotation of the hydraulic motor 54 by changing the inclination of the movable swash plate of the hydraulic pump 53. The rotation angle of the trunnion shaft 7 connected to the movable swash plate is changed by a hydraulic cylinder 8 that detects the movement of the forward / reverse lever 16, the forward pedal 3 and the reverse pedal 4 and is operated by a microcomputer. The rotation of the motor output shaft 24 is changed. The rotation of the pump output shaft 23 connected to the hydraulic pump 53 is the same as the rotation speed of the input shaft 52.

  The rotation of the pump output shaft 23 is transmitted from the PTO first intermediate shaft 55 to the PTO second intermediate shaft 39 via the first gear 34, the second gear 35 and the third gear 36. The PTO input shaft 40 and the PTO first gear case 56 and the gear transmission 41 in the PTO second gear case 57 change the speed and branch the power from the directly connected PTO input shaft 40, and finally the rotation is taken out by the rear PTO output shaft 42 and the intermediate PTO output shaft 43. And drive a working machine such as a rotary or mower.

  The rotation output of the motor output shaft 24 is transmitted to the relay shaft 28 through the fourth gear 25, the fifth gear 26, and the sixth gear 27, and the gear shaft 29 directly connected to the relay shaft 28 is rotated. Then, the clutch gear 30 is meshed with each gear of the gear shaft 29 to shift the transmission to the traveling shaft 31, and the bevel gear 32 of the traveling shaft 31 is meshed with the bevel gear 33 of the rear wheel driving shaft 58 to drive the rear wheel driving shaft 58. To do. The rotation of the traveling shaft 31 appropriately drives the front wheel drive shaft 47 via the seventh gear 45 and the clutch gear 46.

A work machine operation case 48 having a lift arm 50 and a hydraulic cylinder 49 is mounted on the rear upper part of the rear case 19.
As shown in FIGS. 4 and 5, the bracket 60 for mounting the forward pedal 3 and the reverse pedal 4 is attached to the bottom side of the floor panel 2, and a member for rotating the trunnion shaft 7 of the HST 6 is attached to the intermediate case 18 of the transmission case 1. The hydraulic cylinder 8 is attached to the front case 17 of the transmission case 1.

Next, the configuration of the forward pedal 3 and the reverse pedal 4 will be described with reference to FIGS.
The forward pedal 3 and the reverse pedal 4 project the arms 62 and 63 pivotally supported on the pivot shaft 61 of the bracket 60 attached to the bottom surface side of the floor panel 2 on the upper surface of the floor panel 2, and upper ends of the arms 62 and 63. Installed on. The arms 62 and 63 are respectively rotatable on the pivot shaft 61 and are linked to a sensor cylinder 67 pivotally supported on another pivot shaft 66 provided on the bracket 60 on the rear side of the pivot shaft 61. , 65 are connected from above and below. Accordingly, when the forward pedal 3 and the reverse pedal 4 are stepped on, the other is lifted, and if the forward pedal 3 and the reverse pedal 4 are stepped on at the same time, the forward pedal 3 and the reverse pedal 4 cannot be stepped on, thereby preventing erroneous operation. .

  A sensor arm 68 provided with a pin 84 at the tip is fixed to the sensor cylinder 67, and the pin 84 rotates around the pivot shaft 66 when the forward pedal 3 and the reverse pedal 4 are depressed. The arm 85 of the speed change sensor 5, which is a potentiometer that detects the movement of the pin 84, is engaged. Since the shift sensor 5 detects the movement of the forward pedal 3 and the reverse pedal 4 by one, the cost is reduced.

  Further, the sensor cylinder 67 is provided with a brake 91 for stopping the rotation, and when an auto cruise lever connected to the brake arm 91a of the brake 91 by a spring 92 and a wire 93 is inserted, the sensor cylinder 67 is fixed and fixed. The traveling speed at the position is maintained.

  As shown in FIG. 12, the auto cruise is provided with an auto cruise valve V1 between the hydraulic cylinder 8 and the operation valve V, and the flow of oil in the hydraulic cylinder 8 is stopped by the auto cruise valve V1. You may make it drive | work at speed.

  The sensor cylinder 67 is provided with a torsion spring 9 for returning the forward pedal 3 and the reverse pedal 4 to the neutral position. When the depression is stopped, the sensor cylinder 67 returns to the neutral position and serves as a depression resistance at the time of depression. Since the torsion spring 9 is provided on the sensor cylinder 67 which is provided with a pin 84 for rotating the arm 85 of the speed change sensor 5 and to which the sensor arm 68 is fixed, the movement of the forward pedal 3 and the reverse pedal 4 is accurately determined. To tell.

  The control valve is operated by the microcomputer at the shift angle detected by the shift sensor 5, that is, the degree of depression of the forward pedal 3 and the reverse pedal 4, and the trunnion shaft 7 of the HST 6 is rotated by the hydraulic cylinder 8 to control the traveling speed in the forward / rearward direction. However, the operation configuration of the trunnion shaft 7 will be described with reference to FIGS.

  The cam plate 71 is fixed to the trunnion shaft 7 protruding from the intermediate case 18 of the transmission case 1, and the operating arm 73 and the cam plate 71 are pivotally supported on a support shaft 75 erected on a shift plate 74 attached to the intermediate case 18. It is connected by a rod 72 that can be adjusted in length. The rod of the hydraulic cylinder 8 attached to the front case 17 of the transmission case 1 is connected to the tip of the operating arm 73. Therefore, when the hydraulic cylinder 8 is expanded and contracted, the operating arm 73 is rotated, and accordingly, the cam plate 71 connected by the rod 72 is rotated and the trunnion shaft 7 is rotated. By connecting the hydraulic cylinder 8 to the distal end side of the operating arm 73 and connecting the rod 72 to the base side, the movement of the rod of the hydraulic cylinder 8 is finely transmitted to the cam plate 71 and the rotation angle of the trunnion shaft 7 is finely adjusted. it can.

  A sensor arm 82 is attached to the operating arm 73 in the rearward direction, and the arm 86 of the shift angle sensor 81 is engaged with the pin 83 of the sensor arm 73 to rotate the operating arm 73, that is, the rotation angle of the trunnion shaft 7. To detect.

  The neutral holding mechanism of the trunnion shaft 7 includes a roller 77 provided on the other arm by a spring 79 that hooks one arm of an L-shaped arm 78 pivotally supported on the shift plate 74 between a bracket 80 attached to the intermediate case 18. When the roller 77 is pressed against the end surface of the cam plate 71 and enters the recess of the end surface of the cam plate 71, the trunnion shaft 7 returns to the neutral position. When the rod 88 connected to the arm 87 is connected to the arm tip of the L-shaped arm 78 on the side where the spring 79 is attached, the arm 87 is connected to the brake lever by the spring 89 and the wire 90, and the brake lever is pulled. The L-shaped arm 78 is rotated via the rod 87 and the rod 88, and the roller 77 is dropped into the concave portion of the cam plate 71 to return the trunnion shaft 7 to the neutral position.

  An operation valve that controls expansion and contraction of the hydraulic cylinder 8 is not shown, but is attached to the intermediate case 18. Further, when the hydraulic cylinder 8 is attached to the rear case 19 side, the jumping mud becomes difficult to enter the cylinder case.

  In this embodiment, a configuration in which the hydraulic cylinder 8 is used as an actuator for rotating the trunnion shaft 7 is shown, but the present invention can also be implemented with a configuration in which the trunnion shaft 7 is directly rotated by a hydraulic motor.

  Further, as shown in FIG. 13, in addition to the operating valve V for operating the hydraulic cylinder 8, a manual valve V2 is provided in parallel, and when the operating valve V does not move due to a trouble with electrical equipment, the manual valve V2 is moved with the lever R. It can also be operated to enable travel.

  Although not shown, the hydraulic cylinder 8 is configured to return to the neutral position with a spring, and a pressure relief valve is provided between the hydraulic cylinder 8 and the operation valve V to reduce the pressure when the trunnion shaft 7 is returned to neutral. The oil pressure in the hydraulic cylinder 8 can be released with a release valve.

  Whether the trunnion shaft 7 is in the neutral position is detected by the shift angle sensor 81 as described above. A gear rotation sensor for detecting the rotation of the first gear 34 in the transmission case 1 is provided, and this gear is provided. If the stoppage of travel is determined based on the zero rotation detected by the rotation sensor and the neutral position of the trunnion shaft 7 detected by the shift angle sensor 81, it is safe to reliably determine the stoppage of travel even if one of them fails. .

  A rotary for plowing soil is attached to the lift arm 50 and then the rotary is rotated by driving the PTO output shaft 42. At this time, when starting the tillage work from the highest lifted non-working position or when starting the tillage work after raising the rotary by turning, it is safe to lower it to the position just before the grounding without rotating the rotary. After confirming the above, it is raised slightly again, and after starting to rotate the rotary, it is lowered and controlled to perform tilling. At that time, if the automatic forward / reverse rotation control is set, the rotary starts to ground and slips in the reverse rotation, and after a certain time, the reverse rotation is gradually switched to the normal rotation and the tilling is continued.

  In addition, when plowing is started in the forward rotation, if the rotary is grounded and dashing is likely to occur, the rotary is slightly raised and lowered, or the rotation of the rotary is reduced or stopped and again The rotary drive is turned off, or the rotary drive is turned off and idled, or the rotary rotation is temporarily reversed, or the driving drive clutch is disconnected and the front wheel 14 and the rear wheel 15 are braked. The rotation is gradually increased after the rotary drive clutch is made a half clutch or the rotation of the rotary is reduced.

  When starting tillage with the rotary lifted up, in addition to the above control, when straight running is detected, the time from the vehicle speed until the rotary touches down is calculated, the lift arm 50 is lowered, and the lift arm 50 When the lower link becomes horizontal, the rotary starts rotating, the rear wheel 15 is braked before the rotary contacts the ground, and the rotary is slowly lowered to start tilling to prevent dashing.

  When turning during the plowing operation, the rotary is stopped at the start of turning and slightly lifted from the ground. After the turning is finished, the rotary is started to rotate and lowered so as to continue tilling. Further, when the rotary rotation is switched between forward and reverse during the tilling operation, the ground leveling condition and the finished condition are improved by rotating the trunnion shaft 7 to the low speed side to decrease the traveling speed and the engine rotation.

  When controlling the descending speed of the rotary, there are an acceleration sensor and a Doppler sensor as means for detecting the descending speed. The acceleration sensor is attached to the upper part of the rotary, the rotary cover, the lift arm 50 or the lower link. Or it is set as the structure which attaches a microwave irradiation part to the working machine with which a rotary cover or the lift arm 50 is mounted | worn toward a agricultural field.

3, 4 Speed change pedal (3: Forward pedal 4: Reverse pedal)
5 Transmission sensor 6 Hydraulic continuously variable transmission 7 Trunnion shaft 8 Actuator (hydraulic cylinder)
9 Torsion spring 66 Pivot shaft 68 Sensor arm

Claims (1)

  The movement of the forward shift pedal (3) and the reverse shift pedal (4) for moving the vehicle forward and backward is converted into rotation of the sensor arm (68), and the rotation of the sensor arm (68) is detected by the shift sensor (5). In the working vehicle in which the trunnion shaft (7) of the hydraulic continuously variable transmission (6) is rotated by the actuator (8) in accordance with the detection signal of the transmission sensor (5), the sensor arm (68) The work vehicle is configured to return the position of the sensor arm (68) to the neutral position by the urging force of the torsion spring (9) provided on the pivot shaft (66).

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