JP2011102057A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device capable of surely switching two-wheel steering and four-wheel steering with a simple structure, without using a complicated expansive mechanism and control. <P>SOLUTION: Since a steering switching mechanism 54 is provided for switching to the four-wheel steering by connecting a rear wheel steering mechanism 53 and the two-wheel steering by releasing the connection of the rear wheel steering mechanism 53, to an operation part 51 connected with a front wheel steering mechanism 52, the two-wheel steering and the four-wheel steering can be surely switched with the simple structure without requiring the complicated mechanism and the control. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steering device capable of switching between four-wheel steering and two-wheel steering used in, for example, a work vehicle for agricultural work or building construction.

  Conventionally, as this type of steering device, a front wheel steering mechanism that steers the front wheels of the vehicle body, a rear wheel steering mechanism that steers the rear wheels of the vehicle body, and an operation that operates one or both of the front wheel steering mechanism and the rear wheel steering mechanism. And two-wheel steering for steering only one of the front-wheel steering mechanism and the rear-wheel steering mechanism and four-wheel steering for steering both the front-wheel steering mechanism and the rear-wheel steering mechanism are known. (For example, refer to Patent Document 1).

JP-A-9-221055

  In the steering device, a hydraulic drive mechanism is used to drive the front wheel steering mechanism and the rear wheel steering mechanism. The hydraulic drive mechanism forms a hydraulic circuit by connecting a plurality of devices such as hydraulic cylinders, hydraulic pumps and valves with piping for circulating hydraulic oil, making the structure complicated and operating the hydraulic pump Control of valve opening and closing is necessary. For this reason, the steering device equipped with a hydraulic drive mechanism has a complicated structure, and the operation of the hydraulic pump for switching between two-wheel steering and four-wheel steering and the control of opening and closing of the valve are complicated, resulting in a manufacturing cost. Becomes higher.

  An object of the present invention is to provide a steering device that can reliably switch between two-wheel steering and four-wheel steering with a simple structure without using complicated and expensive mechanisms and controls.

  In order to achieve the above object, the present invention is provided with a front wheel steering mechanism for steering the front wheels of the vehicle body, a rear wheel steering mechanism for steering the rear wheels of the vehicle body, and a vehicle body rotatably provided. A steering device having an operation unit for operating one or both of the steering mechanisms, wherein the front wheel steering mechanism and the rear wheel steering mechanism are connected to an operation unit to which one of the front wheel steering mechanism and the rear wheel steering mechanism is connected. A steering switching mechanism is provided in which the other is connected to provide four-wheel steering, and the other of the front wheel steering mechanism and the rear wheel steering mechanism is released to perform two-wheel steering.

  As a result, two-wheel steering and four-wheel steering can be switched by connecting and releasing the other of the front-wheel steering mechanism and the rear-wheel steering mechanism with respect to the operation unit, so that two-wheel steering and four-wheel steering can be switched reliably with a simple structure. It is done.

  According to the present invention, it is possible to reliably switch between two-wheel steering and four-wheel steering with a simple structure without requiring a complicated mechanism or control, so that the manufacturing cost can be reduced.

It is a side view of an aerial work vehicle showing an embodiment of the present invention. It is a front view of an aerial work vehicle. It is a top view which shows the front-wheel steering mechanism and rear-wheel steering mechanism by the side of a trolley | bogie. It is principal part side surface sectional drawing which shows a steering switching mechanism. It is a principal part top view which shows a steering switching mechanism. It is a figure which shows the front wheel and rear wheel at the time of two-wheel steering setting. It is a figure which shows the front wheel and rear wheel at the time of four-wheel steering setting.

  1 to 7 show an embodiment of the present invention.

  The steering device of the present invention is applied to a self-propelled aerial work vehicle 10 for performing harvesting work and management work of fruit trees such as apples and citrus fruits.

  The aerial work platform 10 includes a carriage 20 located on the lower side, a lifting device 30 provided on the top of the carriage 20, a work table 40 provided on the upper end of the lifting device 30, a front wheel 22 of the carriage 20, And a steering device 50 for steering one or both of the rear wheels 23.

  The carriage 20 includes a frame 21 formed in a substantially rectangular shape, and front wheels 22 and 22 and rear wheels 23 and 23 provided below the front and rear sides of the left and right sides of the frame 21. On the front and rear sides of the left and right sides of the frame 21, there are provided rotary shafts 24, 24, 25, 25 with the vertical direction as the center of rotation, respectively, and on the lower ends of the rotary shafts 24, 24, 25, 25, respectively. Front wheels 22 and 22 and rear wheels 23 and 23 are provided. Each rotating shaft 24, 24, 25, 25 is located above each front wheel 22, 22 and each rear wheel 23, 23, and each front wheel 22, 22 and each rear wheel 23, 23 can be rotated by 360 °. It is configured. In addition, electric motors 26 and 26 are provided on the inner sides in the width direction of the rear wheels 23 and 23, respectively, and the rear wheels 23 and 23 are provided by the electric motors 26 and 26 so as to be rotatable forward and backward.

  The lifting device 30 includes a pair of left and right first link members 31, 31, a pair of left and right second link members 32, 32, a substantially central portion of the left and right first link members 31, 31, and a second link member 32, A scissor-link type lifting device is constituted by a link shaft 33 extending in the horizontal direction that connects the substantially central portions of 32 in a rotatable manner, and the hydraulic cylinder 34, and moves the work table 40 in the vertical direction with respect to the carriage 20. It is like that.

  The work table 40 is provided with an operation unit 51 (described later) constituting the steering device 50 on the front side of the boarding surface 41, and with a handrail 42 so as to surround both the left and right sides and the rear side.

  The steering device 50 includes an operation unit 51 for performing operations for starting and stopping the aerial work vehicle 10 and changing the traveling direction, and a front wheel steering mechanism 52 for steering the front wheels 22 and 22 by the operation of the operation unit 51. A rear wheel steering mechanism 53 for steering the rear wheels 23 and 23 by operation of the operation unit 51 and a steering switching mechanism 54 for switching between two-wheel steering and four-wheel steering are provided.

  The operation unit 51 includes an operation shaft 51a provided so as to extend upward from the front side of the work table 40, a handle bar 51b provided so as to extend on both sides in the width direction from the upper end of the operation shaft 51a, and the width of the handle bar 51b. And a switch box 51c provided at the center of the direction. The operation shaft 51a is rotatably provided with the central axis as a rotation center, and can be operated by the handle bar 51b. A front wheel steering mechanism 52 is coupled to the lower end side of the operation shaft 51a, and a rear wheel steering mechanism 53 is detachably coupled by a steering switching mechanism 54. The switch box 51c is provided with a switch (not shown) for performing operations such as turning on / off the power, starting and stopping.

The front wheel steering mechanism 52 includes a front wheel side driving disc 52a as a driving rotating body fixed to the lower end side of the operation shaft 51a, and a driven rotating body connected to the upper end sides of the rotating shafts 24, 24 of the front wheels 22, 22. As a sprocket 52b, 52b, a front-wheel drive disc 52a, and a transmission member 52c wound around each sprocket 52b, 52b.
The front wheel side drive disc 52a is made of a disc-shaped member provided so as to rotate together with the operation shaft 51a, and a groove for holding the transmission member 52c is formed in the circumferential direction of the outer peripheral surface.

  The transmission member 52c is wound around the front wheel side drive disc 52a and the sprockets 52b, and both ends are attached to and detached from members 52d located on the front side of the front wheel side drive disc 52a by bolts 52e and nuts 52f. It is designed to be freely fixed. Further, the transmission member 52c is configured by a roller chain 52g made of iron or stainless steel at a portion positioned in the vicinity of each sprocket 52b, 52b, and is formed by a wire rope 52h made of iron or stainless steel. Further, the transmission member 52c is formed in a cylindrical cable housing 52i having flexibility, with both ends fixed to the carriage 20 side and the work table 40 side, respectively, between the carriage 20 and the work table 40. Has been passed.

  The cable housing 52i is configured, for example, by covering the outer peripheral surface and inner peripheral surface of a metal strip formed in a spiral shape with a synthetic resin. Even when the distance between the carriage 20 and the work table 40 changes, the cable housing 52i holds the tension of the transmission member 52c and transmits the rotational force of the front wheel side drive disc 52a to each sprocket via the transmission member 52c. 52b and 52b are transmitted. The cable housing 52i is detachably attached at its end on the work table 40 side to a member 43 on the work table 40 side via a fitting 52j.

  Further, the front wheel steering mechanism 52 rotates the front wheels 22 and 22 in the same direction as the rotation direction of the front wheel side drive disc 52a, and the rotation angle of the front wheel side drive disc 52a (rotation angle of the operation shaft 51a) and each of them. The front wheels 22 and 22 are configured to have the same steering angle.

The rear wheel steering mechanism 53 is provided below the front wheel side drive disc 52a so as to be rotatable with respect to the operation shaft 51a. The side drive disc 53a, sprockets 53b and 53b as driven rotors connected to the upper ends of the rotary shafts 25 and 25 of the rear wheels 23 and 23, the rear wheel side drive disc 53a and the sprockets 53b and 53b It consists of a wound transmission member 53c.
The rear wheel side drive disk 53a is made of a disk-shaped member, and a groove for holding the transmission member 53c is formed in the circumferential direction of the outer peripheral surface.

  The transmission member 53c is wound around the rear wheel side drive disk 53a and the sprockets 53b, 53b, and both ends of the transmission member 53c are bolts 53e and 53d positioned on the front side of the rear wheel side drive disk 53a. The nut 53f is detachably fixed. Similarly to the front wheel steering mechanism 52, the transmission member 53c includes a roller chain 53g at a portion located in the vicinity of each of the sprockets 53b and 53b, and a wire rope 53h at the other portion.

  Further, like the front wheel steering mechanism 52, the transmission member 53c has a portion located between the carriage 20 and the work table 40 passed through the cable housing 53i, so that the distance between the carriage 20 and the work table 40 changes. Even in this case, the rotational force of the rear wheel side drive disk 53a is transmitted to the sprockets 53b and 53b via the transmission member 53c. The cable housing 53i is detachably attached at its end on the work table 40 side to a member 43 on the work table 40 side via a mounting bracket 53j.

  Further, the rear wheel steering mechanism 53 rotates each rear wheel 23, 23 in the same direction as the rotation direction of the rear wheel side drive disc 53a, and the rotation angle of the rear wheel side drive disc 53a and each rear wheel 23, It is comprised so that the rudder angle of 23 may become the same angle.

  The steering switching mechanism 54 is provided on a switching lever 54a connected to a member 53d on the rear wheel side driving disk 53a side and a member 52d on the front wheel side driving disk 52a side, and can be locked with the switching lever 54a. The recess 54b and a lever guide hole 54c provided on the boarding surface 41 of the work table 40 located in front of the operation unit 51 and provided with a switching lever 54a so as to be movable are configured.

  The switching lever 54a is rotatably connected at its lower end side to a member 53d on the rear wheel side drive disc 53a side, and its upper end side is movable back and forth. The locking recess 54b is provided on the front surface of the member 52d on the front wheel side drive disc 52a side so as to receive the switching lever 54a moving rearward. By receiving the switching lever 54a in the locking recess 54b, the front wheel side driving disk 52a and the rear wheel side driving disk 53a are connected by the switching lever 54a so that four-wheel steering is set. In addition, an elastically deformable protrusion provided on the front side in the locking recess 54b so as to extend inward in the width direction from both the left and right sides, and the distance between each other is smaller than the outer diameter of the switching lever 54a. A portion 54d is formed, and the switching lever 54a is received while elastically deforming the protruding portion 54d, thereby preventing the switching lever 54a from coming off from the locking recess 54b.

  The lever guide hole 54c is a four-wheel provided in an arc shape so that the switching lever 54a in a state of being received in the locking recess 54b (when four-wheel steering is set) rotates 90 ° left and right about the operation shaft 51a. Forward from the center in the left-right direction of the four-wheel steering guide portion 54e so that the switching lever 54a can move to a position where the engagement between the steering guide portion 54e and the locking recess 54b of the switching lever 54a is released. The two-wheel steering guide portion 54f extends toward the front. When the switching lever 54a is positioned at the two-wheel steering guide portion 54f (when two-wheel steering is set), the movement of the switching lever 54a in the width direction is restricted by the two-wheel steering guide portion 54f.

  In the steering device configured as described above, when switching between two-wheel steering and four-wheel steering, the front wheels 22 and 22 and the rear wheels 23 and 23 face the front and rear of the aerial work vehicle 10. In this state, the switching lever 54a is moved in the front-rear direction.

  When the switching lever 54a is positioned at the two-wheel steering guide portion 54f of the lever guide hole 54c (when two-wheel steering is set), when the operation portion 51 is operated from the state of FIG. 6A, only the front wheel steering mechanism 52 is In conjunction with the operation shaft 51a, as shown in FIG. 6B, the orientation of the front wheels 22, 22 is changed according to the rotation angle of the operation shaft 51a. At this time, the rotation of the rear wheel side drive disc 53a of the rear wheel steering mechanism 53 is restricted because the switching lever 54a is restricted from moving in the width direction in the two-wheel steering guide portion 54f. The direction of will not change.

  When the switching lever 54a is positioned at the four-wheel steering guide portion 54e of the lever guide hole 54c (when four-wheel steering is set), when the operation portion 51 is operated from the state of FIG. Then, the rear wheel steering mechanism 53 is interlocked with the operation shaft 51a, and the directions of the front wheels 22, 22 and the rear wheels 23, 23 are changed according to the rotation angle of the operation shaft 51a, as shown in FIG. 7B. The When the operation shaft 51a of the operation unit 51 is rotated 90 degrees in the left or right direction, as shown in FIG. 7C, the front wheels and the rear wheels are also rotated 90 ° in conjunction with the operation shaft 51a. Since the vehicle 20 is directed in the left-right direction with respect to the carriage 20, the aerial work vehicle 10 can move to the left side or the right side without changing the direction. At this time, since the switching lever 54a moves along the four-wheel steering guide portion 54e, the rotation of the rear wheel side drive disk 53a of the rear wheel steering mechanism 53 is not restricted.

  Further, the transmission members 52c and 53c are removed from the front wheel side drive disk 52a and the rear wheel side drive disk 53a, respectively, and the end portions on the work table 40 side of the cable housings 52i and 53i are removed, so that the front wheel side drive disk is removed. A transmission member 53c is attached to 52a, a transmission member 52c is attached to the rear wheel drive disk 53a, a cable housing 53i on the rear wheel steering mechanism 53 side is attached to the upper side, and a cable housing 52i on the front wheel steering mechanism 52 side is on the lower side. When attached to the rear wheel 23, the rear wheels 23 and 23 can be steered during two-wheel steering.

  Further, by attaching both end portions of the transmission member 53c to the rear wheel side drive disk 53a in the opposite direction, the rear wheel 23 with respect to the front wheels 22, 22 is shown in FIG. , 23 can be reversed. In this case, since the turning radius is smaller than that during two-wheel steering, it is possible to turn between narrow fruit trees.

  As described above, according to the steering device of the present embodiment, four-wheel steering is achieved by connecting the rear wheel steering mechanism 53 to the operation unit 51 to which the front wheel steering mechanism 52 is connected. Since it has a steering switching mechanism 54 for two-wheel steering by releasing the connection, it is possible to reliably switch between two-wheel steering and four-wheel steering with a simple structure without requiring a complicated mechanism or control. Manufacturing costs can be reduced.

  Further, the steering switching mechanism 54 is detachably provided on the front wheel steering mechanism 52 connected to the operation unit 51, has a switching lever 54 a provided on the rear wheel steering mechanism, and is connected to the operation unit 51. By engaging the switching lever 54a with the steering mechanism 52, the rear wheel steering mechanism 53 is interlocked with the rotation of the operation portion 51, so that the two-wheel steering and the four-wheel steering can be switched by operating the switching lever 54a. In addition, it is possible to improve the efficiency of switching work between two-wheel steering and four-wheel steering.

  Further, the front wheel steering mechanism 52 includes a front wheel side drive disc 52a that rotates together with the operation unit 51, sprockets 52b and 52b connected to the rotation shafts 24 and 24 of the front wheels 22 and 22, a front wheel side drive disc 52a, The rear wheel steering mechanism 53 is configured to be rotatable with respect to the operation unit 51, and is configured to be rotatable with the operation shaft 51a by the steering switching mechanism 54. The transmission member 52c is wound around each of the sprockets 52b and 52b. The rear wheel side drive disk 53a, the sprockets 53b and 53b connected to the rotating shafts 25 and 25 of the rear wheels 23 and 23, the rear wheel side drive disk 53a and the sprockets 53b and 53b are wound around. And a switching lever connected to the rear wheel side drive disk 53a of the rear wheel steering mechanism 53 and the front wheel side drive disk 52a of the front wheel steering mechanism 52. Since the locking recess 54b for locking and disengaging 54a is provided, the front wheel steering mechanism 52 and the rear wheel steering mechanism 53 having a simple structure are switched between two-wheel steering and four-wheel steering by the switching lever 54a. Therefore, it is possible to simultaneously reduce the manufacturing cost and increase the efficiency of the switching operation between two-wheel steering and four-wheel steering.

  Further, when the two-wheel steering is set, the rotation of the rear wheel side drive disc 53a of the rear wheel steering mechanism 53 is restricted by restricting the movement of the switching lever 54a in the width direction by the two-wheel steering guide portion 54f. Therefore, it is possible to prevent the rear wheels 23 and 23 from inadvertently rotating in the steering direction when the two-wheel steering is set, and it is possible to prevent the operability from being deteriorated when the two-wheel steering is set.

  The transmission member 52c of the front wheel steering mechanism 52 and the transmission member 53c of the rear wheel steering mechanism 53 are provided detachably with respect to the front wheel side drive disk 52a and the rear wheel side drive disk 53a, respectively. 52c can be attached to the rear wheel side drive disk 53a, and the transmission member 53c of the rear wheel steering mechanism 53 can be attached to the front wheel side drive disk 52a, so that only the front wheels are steered when setting the two-wheel steering. It is possible to switch to a setting for steering only the rear wheels, and it is possible to change the setting according to the use situation.

  Further, rotational shafts 24, 24, 25, 25 in the steering direction of the front wheels 22, 22 and the rear wheels 23, 23 are provided above the front wheels 22, 22 and the rear wheels 23, 23, respectively. Since the sprockets 52b, 52b, 53b, and 53b are provided on the 24, 25, and 25, respectively, the front wheels 22, 22 and the rear wheels 23, 23 are rotated 360 degrees around the rotation shafts 24, 24, 25, and 25, respectively. By making the rudder angles of the front wheels 22, 22 and the rear wheels 23, 23 90 °, it is possible to move in the left-right direction without changing the direction of the carriage 20, and to improve operability. It becomes possible. Thereby, in the aerial work vehicle 10 equipped with the steering device of the present invention, it is possible to reduce travel such as turning back when moving to a target position, and it is possible to improve work efficiency.

  In the above-described embodiment, the rear wheel steering mechanism 53 is connected to the operation shaft 51a by locking the switching lever 54a connected to the member 53d on the rear wheel side drive disk 53a side to the front wheel side drive disk 52a. However, for example, even if the switching lever connected to the rear wheel side drive disc 53a is locked to the operation shaft 51a, the same effect as in the above embodiment can be obtained. it can.

  In the above embodiment, the front wheel steering mechanism 52 and the rear wheel steering mechanism 53 are configured to have the same steering angle as the rotation angle of the operation shaft 51a. However, the sprockets 52b, 52b, 53b, By changing the number of teeth of 53b, the rotation angle of the operating shaft 51a and the steering angles of the front wheels 22, 22 and the rear wheels 23, 23 can be changed. For example, by increasing the number of teeth than the sprockets 52b, 52b, 53b, 53b of the embodiment, the steering angles of the front wheel steering mechanism 52 and the rear wheel steering mechanism 53 are made smaller than the rotation angle of the operation shaft 51a. It is possible to reduce the force required for operating the operation unit 51. Further, by reducing the number of teeth as compared with each of the sprockets 52b, 52b, 53b, 53b, the force required for the operation of the operation unit 51 is increased, but the front wheel steering mechanism 52 and the rear wheel are larger than the rotation angle of the operation shaft 51a. The steering angle of the steering mechanism 53 can be increased.

  DESCRIPTION OF SYMBOLS 20 ... Carriage, 21 ... Frame, 22 ... Front wheel, 23 ... Rear wheel, 24 ... Rotation shaft, 25 ... Rotation shaft, 51 ... Operation part, 51a ... Operation shaft, 52 ... Front wheel steering mechanism, 52a ... Front wheel side drive disk 52b ... sprocket, 52c ... transmission member, 52d ... member, 52e ... bolt, 52f ... nut, 53 ... rear wheel steering mechanism, 53a ... rear wheel side drive disk, 53b ... sprocket, 53c ... transmission member, 53d ... member 53e ... bolts, 53f ... nuts, 54 ... steering switching mechanism, 54a ... switching lever, 54b ... locking recess, 54c ... lever guide hole, 54f ... two-wheel steering guide portion.

Claims (6)

A front wheel steering mechanism that steers the front wheels of the vehicle body, a rear wheel steering mechanism that steers the rear wheels of the vehicle body, an operation unit that is rotatably provided on the vehicle body and operates one or both of the front wheel steering mechanism and the rear wheel steering mechanism; A steering device comprising:
Four-wheel steering is achieved by connecting the other of the front wheel steering mechanism and the rear wheel steering mechanism to the operation unit to which one of the front wheel steering mechanism and the rear wheel steering mechanism is connected, and the other of the front wheel steering mechanism and the rear wheel steering mechanism. A steering device comprising a steering switching mechanism for two-wheel steering by releasing the connection. The steering switching mechanism is detachably provided in one of the front wheel steering mechanism and the rear wheel steering mechanism connected to the operation unit or the operation unit, and a switching lever provided in the other of the front wheel steering mechanism and the rear wheel steering mechanism. And having the other of the front wheel steering mechanism and the rear wheel steering mechanism interlocked with the rotation of the operation unit by engaging the switching lever with one or the operation unit of the front wheel steering mechanism and the rear wheel steering mechanism connected to the operation unit. The steering apparatus according to claim 1. The front wheel steering mechanism and the rear wheel steering mechanism are each provided with a drive rotator that is rotatably provided with the operation unit, a driven rotator that rotates in the steering direction together with each front wheel and each rear wheel, a drive rotator, and each driven It comprises a transmission member that is wound around a rotating body and transmits the rotational force of the driving rotating body to each driven rotating body,
One driving rotating body of the front wheel steering mechanism and the rear wheel steering mechanism operated by the operating section when setting two-wheel steering is connected to the operating section, and the other driving rotating body of the front wheel steering mechanism and the rear wheel steering mechanism is used as the operating section. It can be rotated freely,
A locking portion is provided on one drive rotator side of the front wheel steering mechanism and the rear wheel steering mechanism to releasably lock a switching lever connected to the other drive rotator side of the front wheel steering mechanism and the rear wheel steering mechanism. The steering apparatus according to claim 2. The steering apparatus according to claim 3, further comprising means for restricting rotation of the other drive rotating body of the front wheel steering mechanism and the rear wheel steering mechanism when two-wheel steering is set. The transmission members of the front wheel steering mechanism and the rear wheel steering mechanism are provided detachably with respect to the respective drive rotators,
The transmission member of the front wheel steering mechanism can be attached to the drive rotator of the rear wheel steering mechanism, and the transmission member of the rear wheel steering mechanism can be attached to the drive rotator of the front wheel steering mechanism. Item 5. The steering device according to Item 3 or 4. A rotation axis in the steering direction of each front wheel and each rear wheel is provided above the front wheel and the rear wheel, respectively.
The steering device according to any one of claims 3 to 5, wherein each rotating shaft is provided with a driven rotating body.

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