JP2009234474A - Steering structure of working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering structure of a working machine capable of easily performing rectilinear steering and lightly performing an abrupt machine body direction change. <P>SOLUTION: A steering operation tool and a steering wheel are interlocked and connected via a nonlinear transmission mechanism to have a linear relation in which a steered amount of the steering wheel is in substantially direct in proportion to an operation amount of the steering operation tool in an initial operation region from the straight advancing state of the steering operation tool, and to have a nonlinear relation in which a change rate of the steered amount of the steering wheel becomes larger than that of the operation amount of the steering operation tool in a succeeding operation region. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a steering structure for a work machine such as a rice transplanter or an agricultural tractor.

In a riding-type rice transplanter that is an example of a working machine, a knuckle that steers left and right steering wheels and left and right steering wheels that are linearly moved left and right by a steering handle turning operation as a steering operating tool. A steering structure in which an arm is interlocked with a tie rod is employed (for example, see Patent Document 1).
JP-A-2005-170200

  The steering structure is configured such that the front wheel is steered to the maximum when the steering handle is rotated about two turns left or right from a straight traveling state. As a result, the steering angle of the front wheels with respect to the unit operation amount of the steering handle is small, and there is no fear of excessive steering when performing planting travel, and it is possible to perform steering with good straightness. On the other hand, in order to change the direction by turning the airframe U-turn at the shore, it is necessary to quickly rotate the steering handle in order to steer the front wheels greatly, which is a troublesome operation.

  The present invention has been made paying attention to such points, and has as its main purpose to easily perform straight-ahead maneuvering and to easily perform abrupt aircraft direction change.

  In the first aspect of the invention, in the initial operation range from the straight traveling state of the steering operation tool, the steering amount of the steering wheel with respect to the operation amount of the steering operation tool has a linear relationship that is substantially directly proportional. The steering operation tool and the steered wheel are linked via a non-linear transmission mechanism so that the non-linear relationship in which the rate of change of the steered wheel is larger than the rate of change of the steered wheel. Features.

  According to the above configuration, when performing a work traveling straight or substantially straight, the steering angle of the steering wheel with respect to the unit operation amount of the steering operation tool becomes relatively small, and the steering wheel may be excessively steered. It is possible to control with less meandering. When turning the aircraft to make a U-turn, the steering angle of the steering wheel with respect to the unit operation amount of the steering operation tool becomes relatively large. It can be steered efficiently and can perform so-called “swift turn”.

  Therefore, according to the first aspect of the present invention, it is possible to easily perform straight-ahead maneuvering and to easily change the aircraft direction rapidly.

According to a second invention, in the first invention,
An acceleration transmission mechanism is interposed between the nonlinear transmission mechanism and the steering wheel.

  According to the above configuration, the steering wheel can be steered by the same amount by reducing the amount of operation of the steering operation tool as compared with the case where no speed increasing transmission mechanism is interposed, and the straight body can be easily operated, and the fuselage A rapid and large steering of the steering wheel during the direction change can be performed more quickly.

According to a third invention, in the second invention,
A torque generator is interposed between the nonlinear transmission mechanism and the steering wheel.

  According to the above configuration, a large steering reaction force works when steering the steering wheel rapidly and largely, but the steering operation force of the steering operation tool can be small, and the aircraft direction change can be performed lightly and quickly. it can.

According to a fourth invention, in the third invention,
A torque generator is installed under the transmission of the speed increasing transmission mechanism.

  According to the above configuration, since the operation load acting on the speed increasing transmission mechanism can be reduced, a transmission member such as a gear can be made small, which is effective in reducing the size of the speed increasing transmission mechanism. Become.

A fifth invention is the invention according to any one of the first to fourth inventions,
The non-linear transmission mechanism is composed of an eccentric gear transmission mechanism.

  According to the above configuration, it is possible to configure a transmission gear that performs non-linear transmission simply by biasing the rotational axis of the gear processed into a circular shape, and when performing similar non-linear transmission using an elliptical gear or a non-circular gear. Compared to gears, it is easier to machine and can be manufactured at lower cost.

In a sixth aspect based on the fifth aspect,
The eccentric gear transmission mechanism is accommodated and arranged in a transmission gear case, and the transmission gear case is provided with an opening through which a gear peripheral portion can be monitored.

  According to the above configuration, when the eccentric gear is incorporated into the transmission gear case, the rotational phase alignment is facilitated, the assembly workability is excellent, and the inspection and maintenance are convenient.

A seventh invention is the invention according to any one of the first to sixth inventions,
The steering transmission by the non-linear transmission mechanism and the linear steering transmission not via the non-linear transmission mechanism are selectable.

  According to the above configuration, it is possible to perform a maneuver in a state of excellent straight maneuverability and turning operability by selecting non-linear transmission in work traveling that frequently performs straight traveling and rapid aircraft direction change. it can. By selecting linear transmission for mobile travel that does not frequently undergo sudden aircraft direction changes, it is possible to perform maneuvering with a constant maneuvering characteristic from the start of maneuvering to maximum maneuvering. It is possible to maneuver lightly without bringing

In an eighth aspect based on the seventh aspect,
When the traveling transmission system is in a working low speed shift state, the steering transmission state is achieved by the non-linear transmission mechanism, and when the traveling transmission system transmission is in the traveling high speed transmission state, the nonlinear transmission mechanism is not used. It is configured to provide a linear steering transmission state.

  According to the above configuration, a steering state suitable for work traveling and traveling travel is automatically provided, and it is not necessary for the operator to select a steering state corresponding to work traveling and traveling traveling. It will be even better.

According to a ninth invention, in any one of the first to eighth inventions,
In the initial operation range from the straight running state of the steering operation tool, the steering mechanism is operated by operating the steering operation tool in which the left and right moving member linked to the steering operation tool and the knuckle arm that steers the steering wheel are connected by a tie rod. A linear relationship in which the steering amount of the steered wheel with respect to the amount is in a linear relationship that is substantially directly proportional, and in the subsequent operation range, the rate of change of the steering wheel steered amount is greater than the rate of change of the steered wheel operation amount. Is set to the characteristic.

  According to the above configuration, in addition to moving the right and left moving member by non-linear transmission, the steering link mechanism can also operate the steering wheel in a non-linear manner, thereby making it possible to more easily perform straight-ahead maneuvering and drastically change the aircraft direction. Can be done lightly.

  FIG. 1 shows an entire side surface of a rice transplanter as an example of a working machine according to the present invention, and FIG. 2 shows an entire plane. This rice transplanter has a parallel four-link linkage structure driven by a hydraulic cylinder 4 at the rear of a four-wheel drive type traveling machine body 3 having a front wheel 1 as a steering wheel and a rear wheel 2 that cannot be steered. The seedling planting device 6 is connected via the mechanism 5, and a fertilizer device 8 is provided on the rear side of the driver seat 7 provided at the rear portion of the traveling machine body 3, and the front part of the traveling machine body 3 is covered with the bonnet 9. The engine 10, the front panel 11, a steering handle 12 as a steering operation tool, and the like are provided.

  The seedling planting device 6 is configured in a four-row planting specification, and seedlings are placed one by one from the lower end of the seedling stage 15 on which the seedlings are placed and reciprocated horizontally by a fixed stroke. It comprises four sets of rotary planting mechanisms 16 planted on the surface, three leveling floats 17 for leveling the planting location on the surface, and the like.

  The fertilizer application device 8 feeds the powdered fertilizer stored in the fertilizer hopper 18 by a set amount by a feeding mechanism 19 provided at the lower end of the hopper, and supplies the fed fertilizer by four conveying air from the electric blower 20. It sends out to the hose 21 and wind-carrying it to the four groovers 22 attached to the leveling float 17, and feeds fertilizer into the fertilizer grooves formed on the rice field near the side of the planted seedling by the groovers 22 and embeds them. It is configured as follows.

  A mission case 25 is provided at the front of the traveling machine body 3, and a rotating case 26 that pivotally supports the front wheel 1 at the end of a front axle case 25 a that projects laterally from the front left and right of the mission case 25. Is equipped to be steerable around the longitudinal axis P. A pair of left and right swing cases 28 elastically supported by a suspension mechanism 27 are mounted on the rear part of the transmission case 25 so as to be able to swing up and down independently around the base end fulcrum a. Each is pivotally supported.

  As shown in FIG. 3, the engine 10 is a horizontal axis type air-cooled gasoline engine, and a cylinder portion 10 b connected to an upper portion of the crankcase portion 10 a is configured to be low in volume and inclined rearward. The front frame 29 projecting forward from the mission case 25 is mounted and supported in an anti-vibration state.

  A hydraulic continuously variable transmission (HST) 30 is connected to the left side surface of the transmission case 25 as a main transmission, and is linked to the engine 10 by a belt. The transmission output of the continuously variable transmission 30 is transmitted to the mission case 25 and branched into the traveling system and the planting system, the traveling system power is transmitted to the left and right front wheels 1, and the left and right rear wheels 2 via the swing case 28. The power of the branched planting system transmitted to the rear is taken out rearward of the machine body and transmitted axially to the seedling planting device 6.

  Next, a steering structure for steering the front wheel 1 will be described. As shown in FIG. 4, a knuckle arm 31 is attached to the left and right rotating cases 26 that pivotally support the front wheel 1, and the left and right knuckle arms 31 are interlocked and connected to a rack and pinion type steering mechanism 32. . As shown in FIG. 5, the steering mechanism 32 is disposed at a corner portion at the lower front end of the transmission case 25, and has a rack rod 33 that penetrates the transmission case 25 so as to be laterally movable, and a rear surface of the rack rod 33. And a pinion gear 34 that meshes with a rack gear 33a. As shown in FIGS. 4 and 6, both ends of a rack rod 33 projecting left and right from the mission case 25 and the left and right knuckle arms 31 are interlocked and connected by tie rods 35, and both ends of the rack rod 33 are connected to each other. A bellows-like stretchable boot 36 is attached to the rack case insertion boss 25c of the mission case 25 to protect the rack case 33 from muddy water.

  The pinion gear 34 is formed integrally with a lower portion of a pinion operation shaft 37 that is inserted and arranged in a vertical posture at the front portion of the mission case 25, and the upper end of the pinion operation shaft 37 is attached to the upper end of the mission case 25. An input operation shaft 40 provided on the upper surface of the torque generator 38 and the steering handle 12 are linked as described below. The input operation shaft 40 is connected to an output operation shaft 39 of a hydraulic torque generator 38.

  As shown in FIG. 3, the steering handle 12 is rotatably supported on an upper portion of a handle post 41 erected on the upper portion of the torque generator 38 via a handle support shaft 42. The input operation shaft 40 is axially linked via a pair of universal joints 43 and 44, and a transmission gear case 45 is interposed in the axis linkage system.

  As shown in FIGS. 7 to 9, the transmission gear case 45 is configured by bolting an upper case 45a and a lower case 45b, and is connected and supported inside a handle post 41 having a U-shaped cross section, An opening k is formed in front of and behind the transmission gear case 45 so that the inside can be monitored. An upward input shaft 46 and a downward output shaft 47 are concentrically mounted at a rear position of the transmission gear case 45 so as to be relatively rotatable, and an intermediate shaft 48 is mounted at a front position of the transmission gear case 45. The upward input shaft 46 and the handle support shaft 42 are interlocked and connected by an upper universal joint 43, and the downward output shaft 47 and the input operation shaft 40 of the torque generator 38 connect the intermediate operation shaft 49 and the lower universal joint 44. It is linked and connected through.

  The upward input shaft 46 and the intermediate shaft 48 are interlocked and connected by the non-linear transmission mechanism A, and the intermediate shaft 48 and the downward output shaft 47 are interlocked and connected by the speed increasing transmission mechanism B. The non-linear transmission mechanism A is an eccentric gear transmission mechanism in which an eccentric gear 51 connected and fixed to the upward input shaft 46 and an eccentric gear 52 of the same number of teeth connected and fixed to the intermediate shaft 48 are engaged. Thus, the intermediate shaft 48 makes one rotation at an unequal speed with respect to one rotation of the upward input shaft 46.

  The speed increasing transmission mechanism B engages a large-diameter gear 53 fixed to the intermediate shaft 48 and a small-diameter gear 54 fixed to the downward output shaft 47 to increase the rotation of the intermediate shaft 48 twice and downward. It is configured to transmit to the output shaft 47.

  According to the above configuration, by rotating the steering handle 12 from the neutral position (straight forward position) to the left or right, the input operation shaft 40 and the output operation shaft 39 of the torque generator 38 are rotated at a double speed, and the output operation shaft The rack cage 33 is moved to the left or right by the pinion operating shaft 37 that rotates integrally with 39, and the front wheel 1 is steered from the straight traveling position to the left or right.

  In this case, the steering angle α of the front wheel 1 with respect to the turning operation angle θ from the straight traveling position of the steering handle 12 to the left or right changes according to the characteristics shown in FIG. That is, in the rotation operation range of about 90 degrees from the straight position of the steering handle 12, the steering angle α of the front wheel 1 is substantially linearly proportional to the rotation operation angle θ of the steering handle 12, and thereafter In the steering wheel operating range, the rate of change of the steering angle α of the front wheel 1 is larger than the rate of change of the steering operation angle θ of the steering handle 12, and the steering handle is rotated by approximately one rotation. The front wheel 1 is set to be steered to the maximum.

  Therefore, during planting traveling straight or substantially straight, since the change in the steering angle α of the front wheel 1 with respect to the turning operation of the steering handle 12 is small, excessive steering of the front wheel 1 is unlikely to occur and straight steering is possible. It becomes easy. In turning the vehicle body at the heel, the front wheel 1 is greatly steered with respect to the steering wheel turning operation by largely turning the steering handle 12, and the direction of the vehicle body can be changed quickly.

  In this example, when the front wheel 1 is steered greatly, the aircraft turning characteristic is automatically switched to the small turning mode. That is, as shown in FIG. 4, the transmission case 25 is provided with a pair of left and right side clutches 55 for intermittently transmitting power to the left and right rear wheels 2. The knuckle arm 31 is linked as follows.

  That is, the left and right knuckle arms 31 and the clutch lever 56 that engages and disengages the left and right side clutches 55 are configured to be interlocked and interlocked with the connecting rod 57 having the long hole interchange c, so that the front wheel 1 is in the straight traveling position. The left and right side clutches 55 are both in the “clutch-engaged” state and the vehicle travels straight by four-wheel drive. When the front wheel 1 is steered less than a set angle (for example, 30 °) from this straight traveling state, the rotation displacement of the knuckle arm 31 is absorbed by the long hole interchange c, and the linkage rod 57 is manipulated. The left and right side clutches 55 are both maintained in the “clutch engaged” state. When the front wheel 1 is steered more than the set angle from the straight traveling state due to a U-turn turning at the shore, etc., only one linkage rod 57 linked to the clutch lever 56 inside the turning is forward. The side clutch 55 inside the turning is switched to the “clutch disengagement” state. Therefore, in this case, the rear wheel 2 on the inside of the turning is in a free-wheeling state, and the body is operated with a small turning radius by the three-wheel drive by the left and right front wheels 1 and the rear wheel 2 on the outside of the turning. To turn.

  FIG. 12 shows a developed embodiment of the present invention. In this example, the eccentric gear 51 of the eccentric gear mechanism that constitutes the non-linear transmission mechanism A is mounted so as to be freely rotatable with respect to the upward input shaft 46 and is slidably fitted to the upward input shaft 46 so as to be slidable. The claw clutch 61 is interposed between the eccentric gear 51 and the small diameter gear 54. According to this configuration, the upward input shaft 46 and the eccentric gear 51 are integrated by sliding the claw clutch 61 upward by the biasing spring 62 and engaging with the eccentric gear 51 as shown in FIG. As described above, the rotational operation force of the upward input shaft 46 can be transmitted to the downward output shaft 47 through the nonlinear transmission mechanism A and the speed increasing transmission mechanism B with the characteristics shown in FIG. it can. Conversely, the upward input shaft 46 and the downward output shaft 47 are integrated by sliding the pawl clutch 61 downward against the biasing spring 62 and engaging with the small-diameter gear 54, so that the nonlinear transmission mechanism A and Without passing through the speed increasing transmission mechanism B, the rotational operation force of the upward input shaft 46 can be directly transmitted to the downward output shaft 47.

  When the upward input shaft 46 and the downward output shaft 47 are directly connected as described above, the front wheel 1 can be steered to the maximum steering angle by rotating the steering handle 12 by about two rotations. In this case, the steering angle α of the front wheel 1 with respect to the turning operation angle θ from the straight traveling position of the steering handle 12 to the left or right changes according to the characteristic indicated by “B” in FIG.

  As shown in FIG. 12, the pawl clutch 61 is linked to the sub-transmission lever 13 that performs the sub-shift of the traveling system in the transmission case 25, and the pawl clutch 61 is operated during planting work for switching the sub-transmission lever 13 to “low”. Is engaged with the eccentric gear 51 to perform steering transmission through the non-linear transmission mechanism A and the speed increasing transmission mechanism B, and the auxiliary transmission lever 13 is switched to “high” during the traveling travel to the claw clutch 56 small diameter gear 54. When engaged and the steering transmission without the non-linear transmission mechanism A and the speed increasing transmission mechanism B is performed, a steering state suitable for the traveling mode can be automatically displayed.

[Other Examples]
(1) As the non-linear transmission mechanism A, a crank type transmission structure can be used.

(2) The speed increasing transmission mechanism B can be changed to a constant speed transmission mechanism. In this case, the steering wheel 12 is rotated by approximately two turns to steer the front wheel 1 to the maximum steering angle.

  (3) As the steering mechanism 32, a structure in which a pitman arm (not shown) that is turned up and down by the torque generator 38 is used as a left and right moving member can be used.

  (4) As shown in FIG. 14, in the initial operation region of the steering mechanism 32 from the straight traveling state of the steering handle 12, the steering angle α of the front wheel 1 with respect to the rotational operation angle θ of the steering handle 12 is substantially directly proportional. In the subsequent operation range, the link characteristic is set so that the change rate of the steering angle α of the front wheel 1 is larger than the change rate of the turning operation angle θ of the steering handle 12. By doing so, it is possible to further straighten the maneuver and to improve the operability when turning the aircraft.

Whole side view of rice transplanter Overall plan view of rice transplanter Side view of the front of the traveling aircraft Plan view of traveling system Longitudinal side view of the front of the mission case Longitudinal front view showing part of the steering structure Vertical side view of transmission gear case Top view of transmission gear case Longitudinal front view of transmission gear case Development plan view showing gear linkage of transmission gear case Characteristic diagram showing the relationship between the steering handle turning angle and the front wheel steering angle Vertical side view showing a transmission gear case of another embodiment Characteristic diagram showing the relationship between the steering operation angle of the steering wheel and the steering angle of the front wheels in another embodiment The top view which shows the steering mechanism in other Examples

Explanation of symbols

1 Steering wheel (front wheel)
12 Steering operation tool (steering handle)
31 Knuckle arm 32 Steering mechanism 33 Left and right moving member (rack rack)
35 Tie rod 38 Torque generator 45 Speed change gear case A Non-linear transmission mechanism B Speed increase transmission mechanism k Opening

Claims (9)

  In the initial operation range from the straight traveling state of the steering operation tool, the steering wheel steering amount is linearly proportional to the operation amount of the steering operation tool. In the subsequent operation range, the steering operation amount of the steering operation tool is The operation characterized in that the steering operation tool and the steered wheel are interlocked and connected via a non-linear transmission mechanism so that the non-linear relationship in which the change rate of the steered wheel steer amount is larger than the change rate. The steering structure of the machine.   The steering structure for a work machine according to claim 1, wherein a speed increasing transmission mechanism is interposed between the nonlinear transmission mechanism and the steering wheel.   The steering structure for a working machine according to claim 2, wherein a torque generator is interposed between the nonlinear transmission mechanism and the steering wheel.   The steering structure for a working machine according to claim 3, wherein the torque generator is disposed below the transmission of the speed increasing transmission mechanism.   The steering structure for a working machine according to any one of claims 1 to 4, wherein the non-linear transmission mechanism is constituted by an eccentric gear transmission mechanism.   6. The steering structure for a working machine according to claim 5, wherein the eccentric gear transmission mechanism is accommodated in a transmission gear case, and an opening capable of monitoring a gear peripheral portion is provided in the transmission gear case.   The steering of the work machine according to any one of claims 1 to 6, wherein the steering transmission by the nonlinear transmission mechanism and the linear steering transmission not via the nonlinear transmission mechanism are selectable. Construction.   When the traveling transmission system transmission is in the working low speed shift state, the non-linear transmission mechanism is in the steering transmission state, and when the traveling transmission system transmission is in the traveling high speed transmission state, the nonlinear transmission mechanism is used. The work machine steering structure according to claim 7, wherein the steering structure is configured to provide a non-linear steering transmission state. In the initial operation range from the straight running state of the steering operation tool, the steering mechanism is operated by operating the steering operation tool in which the left and right moving member linked to the steering operation tool and the knuckle arm that steers the steering wheel are connected by a tie rod. A linear relationship in which the steering amount of the steered wheel with respect to the amount is in a linear relationship that is substantially directly proportional, and in the subsequent operation range, the rate of change of the steering wheel steered amount is greater than the rate of change of the steered wheel operation amount. The steering structure for a work machine according to any one of claims 1 to 8, wherein the steering structure is set to a characteristic that satisfies the following conditions.

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