JP6994956B2 - Work vehicle steering device - Google Patents

Description

The present invention relates to a steering device of a work vehicle, and more particularly to a steering device that changes a traveling direction of a work vehicle by rotating a steering shaft by a steering wheel or a drive unit of an automatic steering device.

For example, agricultural work vehicles such as tractors and rice transplanters drive the front wheels together with the rear wheels and rear wheels, and the front wheels, which are the steering wheels, are steered by the steering wheel to change the direction of travel of the vehicle. I do. If it is a tractor, it can be cultivated or ridged in a field (field), soybeans, etc. can be sown, vegetables can be transplanted, etc. by a working machine connected to the rear of the machine as it travels. , Plant rice seedlings in paddy fields and carry out rice planting work.

By the way, when carrying out these work runs, it is desirable to perform straight ridges and transplants at regular intervals in order to efficiently use the field to increase the yield and facilitate subsequent management. For that purpose, it is necessary to make the work vehicle go straight. However, the work vehicle may sway from side to side due to unevenness in the field, partial hardness, etc. At that time, it requires skill to properly steer the steering wheel with the steering wheel and let the vehicle go straight without swaying. In addition, the physical and mental burden is also great.

Therefore, research on an automatic steering device for moving a work vehicle straight is being conducted. For example, in Patent Document 1, when the position of a distant target imaged by a camera shifts to the left or right, a straight-ahead support controller corrects this. The direction in which the vehicle should go straight is obtained, and the steering controller calculates the left-right correction steering angle based on this, and further operates the front wheel steering unit so that the front wheel steering angle becomes the correction steering angle so that the work vehicle can go straight. ing.

Further, in Patent Document 2, when the work vehicle travels straight based on the image information of the distant target set in advance captured by the camera and then the work vehicle is turned, the image of the trace of the work captured by the camera is obtained. I try to follow the traces based on the information. Further, in Patent Document 3, the work vehicle is automatically controlled to go straight based on the amount of displacement from the traveling reference line by the gyro and the traveling speed.

Japanese Unexamined Patent Publication No. 2010-195252 Japanese Unexamined Patent Publication No. 2012-23997 Japanese Unexamined Patent Publication No. 6-178603

As mentioned above, it is effective to provide an automatic steering device to make the work vehicle run straight or follow the work vehicle in order to reduce the physical and mental burden on the worker and improve the work accuracy. It is a means. However, if it is said that such an automatic steering device is absolutely necessary, it may not be particularly necessary depending on the work content, and the manufacturer will provide an automatic steering device as an option to cope with this.

When the automatic steering device is provided as an option, an automatic steering device as an option is retrofitted based on a work vehicle that is not originally equipped with the automatic steering device. In addition, when retrofitting the automatic steering device, the parts of the existing manual steering device are removed and replaced with new parts of the automatic steering device while performing the recombining work. In this case, unnecessary parts are generated. At the same time, there is a problem that the automatic steering device cannot be provided at a low cost due to the recombining man-hours.

That is, when considering a drive unit that requires a particularly large rearrangement of an automatic steering device, for example, the drive unit described in Patent Document 1 or Patent Document 2 is used from the electric motor when the steering shaft is rotated by the electric motor. A winding transmission device using a chain is used, or a winding transmission device using a gear transmission device and a timing belt is used in combination to rotate the steering shaft. Further, in Patent Document 3, the steering shaft is rotated by using gears directly from the electric motor.

Therefore, in Patent Documents 1 to 3, it is necessary to connect a steering wheel (steering handle) to the upper end of the steering shaft and to integrally provide a driven sprocket and a driven gear below the steering wheel. However, if it is a manual steering device, it is not necessary to integrally provide a driven sprocket and a driven gear for the steering shaft. Therefore, when changing from manual steering to automatic steering, a steering shaft that supports the steering column (steering post) is used. It is necessary to remove it and replace it with a steering shaft equipped with a driven sprocket or the like.

In Patent Documents 1 to 3, a driven sprocket and a driven gear are arranged between the upper end of the steering column and the steering wheel, and the electric motor and other transmission devices are placed on the steering column and the like (existing steering handle). Since the structure can be externally attached, there is an advantage that a highly versatile automatic steering device can be realized (see Patent Document 2).

However, it is dangerous and manual to arrange the driven sprocket and the driven gear between the upper end of the steering column and the steering wheel in this way so that the transmission device is exposed as in Patent Document 1 or Patent Document 3. When dust (foreign matter) such as clothes (sleeve), stone fragments and sand on the hands fall down due to the steering operation of the steering wheel, it falls on the transmission device, causing transmission problems such as dust biting and transmission device. It may cause a failure.

Further, when the transmission device is covered with a cover as in Patent Document 2, safety for the operator can be ensured. However, since it is necessary to provide a hole in the cover for passing the steering wheel toward the upper end of the steering shaft in order to attach the steering wheel to the steering shaft, a gap that allows relative rotation between the hole in the cover and the outer peripheral portion of the steering shaft. It is not possible to deny the possibility that dust will invade the inside through this gap, and there is a risk of causing transmission problems similar to those described above.

In particular, when a gear is used as a transmission device, if dust is caught between the tooth surfaces that mesh with each other, the tooth surface may be damaged due to streaks, or in the worst case, the gear may be locked incapable of rotation. Further, when the gears are locked, not only the automatic steering becomes impossible, but also the steering shaft becomes impossible to rotate, and the manual steering by the steering wheel cannot be performed.

Therefore, in view of the above-mentioned problems, the present invention is based on the premise that when an automatic steering device is retrofitted to a work vehicle, the drive unit thereof is externally attached to form a highly versatile one. It is an object of the present invention to provide a steering device for a work vehicle capable of eliminating as much as possible obstacles due to the intrusion of foreign matter into the transmission device. Similarly, when the automatic steering device is retrofitted, the number of parts to be removed and discarded and the man-hours for recombining can be reduced as much as possible, and the obstacles caused by the intrusion of foreign matter into the transmission device can be eliminated by a simple structure. The challenge is to provide an inexpensive steering device as a whole.

In order to solve the above problems, the present invention first provides a steering wheel and a drive unit of the automatic steering device above the steering column that supports the steering shaft, and the steering wheel or the drive unit of the automatic steering device steers. In the steering device that rotates the shaft to change the traveling direction of the work vehicle, the drive unit of the automatic steering device is a transmission device that transmits the power of the electric motor to the steering shaft and prevents foreign matter from entering the transmission device. The transmission device is configured by the gear transmission device of the external gear, and the joint to which the driven gear of the transmission device is attached is connected to the upper end of the steering shaft, and is also on the driven gear. A mounting shaft that connects the steering wheel to the upper end thereof is fixed, and an enclosure is provided on the upper surface side of the driven gear, and the enclosure constitutes a catching body that prevents foreign matter from entering the transmission device .

Secondly, the present invention constitutes a catching body in which an enclosure is provided on the upper surface of the flange of the mounting shaft provided on the driven gear, and the enclosure prevents foreign matter from entering the transmission device.

Further, the present invention is characterized in that, thirdly, a cushion is provided in the enclosure provided on the upper surface of the flange of the mounting shaft, and the cushion prevents foreign matter from jumping out of the enclosure. Fourth, in the present invention, a seal is provided on the cover covering the upper part of the transmission device, and the gap between the hole formed in the cover and the outer peripheral portion of the hub of the steering wheel or the mounting shaft is closed by the seal. It is characterized by preventing foreign matter from entering the transmission device.

According to the steering device of the work vehicle of the present invention, a steering wheel and a drive unit of the automatic steering device are provided above the steering column that supports the steering shaft, and the steering wheel or the drive unit of the automatic steering device is used to control the steering shaft. Since it is rotated to change the traveling direction of the work vehicle, when the automatic steering device is retrofitted to the work vehicle, the drive unit of the automatic steering device can be externally attached above the steering column, and the drive of the automatic steering device can be driven. The unit can be configured to be highly versatile.

Further, since the drive unit of the automatic steering device includes a transmission device that transmits the power of the electric motor to the steering shaft and a catching body that blocks and catches foreign matter from entering the transmission device, it accompanies manual steering operation. Even if a piece of stone, sand, or other debris tries to fall onto the transmission device, the catcher can catch it and prevent it from entering the transmission device. Therefore, in the worst case, not only the automatic steering becomes impossible, but also the possibility that the manual steering by the steering wheel becomes impossible can be eliminated, and the transmission failure and the failure of the transmission device can be prevented.

Further, the transmission device is configured by the gear transmission device of the external gear, the joint for attaching the driven gear of the transmission device is connected to the upper end portion of the steering shaft, and the steering wheel is connected to the upper end portion on the driven gear. The mounting shaft is fixed , and an enclosure is provided on the upper surface side of the driven gear, and this enclosure constitutes a catching body that prevents foreign matter from entering the transmission device.

With this configuration, the drive unit of the automatic steering device can be mounted between the upper end portion of the steering shaft and the steering wheel, and therefore, the drive unit of the automatic steering device is externally attached above the steering column. At that time, the existing steering shaft can be used as it is and the drive unit can be easily incorporated, and an inexpensive automatic steering device can be provided by reducing the number of parts to be removed and discarded and the number of recombining steps as much as possible.

In addition, when the transmission device is covered with a cover, dust that falls from the gap between the hole in the cover and the hub of the steering wheel or the outer peripheral portion of the mounting shaft falls into the enclosure provided on the upper surface of the flange of the mounting shaft. After that, since the enclosure keeps the falling dust in the enclosure, the dust biting of the gear mechanism of the transmission device can be eliminated, and the dust can be accurately captured by a very simple structure.

Further, if a cushion is provided in the enclosure provided on the upper surface of the flange of the mounting shaft and the cushion prevents foreign matter from splashing out from the enclosure, a gap between the hole of the cover and the hub of the steering wheel or the outer peripheral portion of the mounting shaft is provided. The cushioning effect of the cushion eliminates the risk of dust falling from the steering column tilting toward the driver's seat, so that it bounces off the upper surface of the flange of the mounting shaft, which also tilts, and jumps out over the enclosure. Garbage can be retained in a cushion or an enclosure on its outer periphery.

Then, a seal is provided on the cover that covers the upper part of the transmission device, and the gap between the hole formed in the cover and the outer peripheral portion of the hub of the steering wheel or the mounting shaft is closed by this seal to prevent foreign matter from entering the transmission device. Then, the gap between the hole formed in the cover and the outer peripheral portion of the hub or mounting shaft of the steering wheel is closed by the seal, and the mounting eccentricity between the seal and the hub or mounting shaft, or the axial eccentricity of the hub or mounting shaft On the other hand, the flexibility of the seal allows it to follow this and prevent foreign matter from entering the transmission as much as possible.

It is a side view of the tractor to which this invention is applied. It is a perspective view of a control part. It is a block diagram of an automatic steering device. It is a main part side sectional view which shows the mounting state of the drive part of an automatic steering apparatus. It is a side sectional view of the drive part of an automatic steering apparatus. It is an exploded view seen from the front side of the drive part of an automatic steering apparatus. It is an exploded view seen from the rear side of the drive part of an automatic steering apparatus. It is an exploded view which shows the attachment of a cushion and a seal. It is a perspective view which looked at the cover of a drive part from the back side. It is a cross-sectional view on the main part side which shows the removal of a drive part. It is a perspective view of the 2nd large diameter driven gear. It is a perspective view of a removable jig. It is a perspective view which shows the state which stops the rotation of the 2nd large diameter driven gear. It is a perspective view of a mounting shaft.

An embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the agricultural tractor 1 as a work vehicle constitutes a vehicle body by integrally connecting an engine 2, a clutch housing 3, a transmission 4, and the like from the front. Further, a bonnet 5 and an undercover 6 for covering the engine 2 and auxiliary equipment of the engine 2 are provided near the front portion of the vehicle body, and the bonnet 5 is configured to be openable and closable on the front side via a hinge provided on the rear portion.

Further, the front bracket 7 fixed to the engine 2 and extending forward swings the front axle case to the left and right. Front axle cases (kingpin case and final case) are attached to the left and right ends of this front axle case. Further, the front axle case pivotally supports the front axle 9 to which the front wheels 8 are attached, and the steering wheel 10 provided in the control portion steers the left and right front wheels 8.

On the other hand, rear axle cases connected to the left and right of the transmission case 4 are provided near the rear of the vehicle body, and the left and right rear wheels 12 are attached to the rear axle 11 that is pivotally supported by the rear axle case. Further, a well-known three-point link mechanism consisting of a top link 13 and left and right lower links 14 and a connecting device such as a drawbar are provided at the rear of the vehicle body, and these connecting devices are a rotary tiller, a ridger, or a seeding machine. The engine power is transmitted to the work machine from the PTO shaft (power take-off shaft) that is pivotally supported at the rear of the transmission case 4 by connecting the work machine such as a transplant machine or a transplant machine.

Further, a cabin 15 that covers the control portion via anti-vibration rubber is mounted on the vehicle body behind the engine 2. Here, the cabin 15 is between the front pillar 16 which is a pair of left and right front columns, the rear pillar 17 which is a pair of left and right rear columns, and the upper ends of the four columns 16 and 17 extending in the vertical direction. The cabin frame is composed of a square frame-shaped roof frame 18 for connecting and fixing, and a lower frame 19 and the like for connecting and fixing between the lower ends of the columns 16 and 17.

The left and right door glasses 20 are attached to the cabin frame so as to be openable and closable via hinges 21 provided on the rear side, and a windshield 22 is provided on the front side and a rear glass 23 is provided on the rear side. Further, a fender 25 that covers the front upper side of the rear wheel 12 is extended from the lower ends of the left and right rear pillars 17 toward the floor 24 side diagonally lower and lower in the front direction. Further, the inner roof and the outer roof 26 are attached to the roof frame 18.

Further, the lower frame 19 is provided with a side console 27 and a seat undercover for attaching a driver's seat 28, which is positioned between the left and right fenders 25 and through which an operation lever or the like provided from the vehicle body side is passed. Further, a panel cover 30 and a rear panel cover 31 that cover the periphery of the steering column 29 that stands upright from the vehicle body and is inclined toward the driver's seat 28 side are provided in the center of the floor 24 toward the front portion.

The panel cover 30 is provided with a meter panel 32, an engine starter switch, an operation switch unit 33 for automatically controlling the tractor, and the like. In addition, 34 is a forward / backward advance lever, 35 is an engine control lever, 36 is a combination switch lever, 37 is a work equipment elevating lever, 38 is a main clutch pedal, and 39 is a left and right brake pedal.

Next, an outline of the automatic steering device provided as an option in the tractor 1 will be described. As shown in FIG. 3, the automatic steering device includes an image processing device A, a steering control device B, an operation unit C, a drive unit D, and a front wheel steering angle sensor S. Then, among these, the image processing device A is configured by integrating, for example, a CMOS camera module and a CPU board, and the image processing device A is mounted in the cabin 15 so as to face the upper center side of the windshield 22 and face the inside. Image the scenery (distant view) in front of the car body.

Then, the image processing device A analyzes and extracts information that can be read from the obtained captured image in real time, detects lateral displacement with respect to the straight running or following of the vehicle, and gives a steering instruction to the steering control device B. Further, the steering control device B operates the drive unit D based on the steering instruction of the image processing device A, the instruction of the operation unit C, and the steering angle of the front wheel 8 obtained from the front wheel steering angle sensor S.

Further, the operation unit C issues instructions for mode switching, sensitivity switching, and recognition reset for straight-ahead control / follow-up control to the steering control device B by operating each button, and also displays the detection state of the image processing device A with an LED lamp. Notify using a buzzer. The straight-ahead control / follow-up control includes four types: "distant view straight-ahead control", "previous stroke trace (work trace) follow-up", "aze follow-up", and "V marker follow-up".

Further, the front wheel steering angle sensor S detects the steering angle of the front wheels 8 by a potentiometer, and is mounted on the front axle case in which the differential device of the front wheels 8 is built, and the actuators of the potentiometer are the left and right front wheels. It is linked to the end of the tie rod 40r on one side of the double acting hydraulic cylinder 40 that steers 8.

On the other hand, the drive unit D is composed of an electric motor 41 and a transmission device G that transmits the power of the electric motor 41 to the steering shaft 42, and the steering control device B, the operation unit C, and the drive unit D are one. It is grouped as a control unit U, and this control unit U is attached and provided near the upper part of the steering column 29 that pivotally supports the steering shaft 42.

On the other hand, the steering device of the front wheel 8 is composed of a fully hydraulic power steering device, and this power steering device is a steering shaft 42 and a steering shaft 42 rotated by the steering wheel 10 and the drive unit D of the automatic steering device. It consists of a steering unit 43, a hydraulic hose 44, and a double-acting hydraulic cylinder 40, which are integrally equipped with a direction switching valve operated by rotation and a metering mechanism with servo feedback, or a hydraulic pump that supplies pressure oil to the steering unit 43. , The steering force is reduced by hydraulic pressure so that the front wheels 8 can be steered.

Next, the transmission device G for transmitting the power of the electric motor 41 to the steering shaft 42 together with the attachment of the control unit U to the steering column 29 will be described. As shown in FIG. 4, the upper portion of the steering shaft 42 is rotatably supported by the bush 45 at the upper end of the steering column 29, and is positioned by the C ring 47 via the liner 46.

Further, the combination switch assembly 48 and its cover 49 are mounted near the upper part of the steering column 29 via the mounting seat 29a of the steering column 29. The combination switch assembly 48 includes a turn & light switch operated by the combination switch lever 36 and an elevating switch operated by the work equipment elevating lever 37.

On the other hand, the control unit U has a bracket 51 for mounting the electric motor 41 and the transmission device G or the buzzer 50 constituting the drive unit D, and the electronic boards 52 and 53 for mounting the steering control device B and the operation unit C inside. A resin cover 54 for covering the upper surface side of the drive unit D, a bottom plate 55 for closing the lower side of the drive unit D, and a resin front lower cover 56 provided on the driver's seat 28 side are provided, and these covers 54 are provided. The bottom plate 55 is directly attached to the bracket 51, and the front lower cover 56 is detachably attached to the bracket 51 via the bottom plate 55.

Then, in the control unit U, the lower surface of the bottom plate 55 is in contact with the upper surface of the cover 49 of the combination switch assembly 48 and is mounted on the control unit U, and the front portion of the bracket 51 is covered by the bolt 58 via the mounting plate 57. The control unit U is attached to the steering column 29 via the attachment seat 29a by tightening and attaching the control unit U to the base of the combination switch assembly 48 together with the front portion of the combination switch assembly 48.

Further, when the drive unit D is described in detail, as shown in FIGS. 5 and 8, the electric motor 41 is composed of a stepping motor, and the output shaft thereof is up and down on the left side when viewed from the driver's seat 28 near the rear of the bracket 51. Install so that it faces the direction. Further, a first small-diameter drive gear 59 is attached to the upper end of the output shaft of the stepping motor 41. Further, a first large-diameter driven gear 60 that meshes with the small-diameter drive gear 59 and a second small-diameter drive gear 61 that is integrally provided below the large-diameter driven gear 60 are rotatably supported by the bracket 51.

Then, the second large-diameter driven gear 62 that meshes with the second small-diameter drive gear 61 is integrally provided by welding to the upper part of the joint 63 that rotatably positions and supports the central portion of the bracket 51 via the bearing Br. Therefore, when the stepping motor 41 rotates in the forward and reverse directions, the external gear composed of the first small diameter drive gear 59, the first large diameter driven gear 60, the second small diameter drive gear 61, and the second large diameter driven gear 62 The joint 63 is rotationally driven by the two-stage gear mechanism.

On the other hand, as shown in FIG. 4, the joint 63 fits into the upper end portion of the steering shaft 42 from the upper side when the control unit U is attached to the steering column 29, and the tapers 42a, 63a and serrations 42b, respectively. They are coupled by 63b and both rotate integrally. Note that 64 and 65 are spring washers and nuts, and these are used to securely fasten the joint 63 to the upper end portion of the steering shaft 42.

Therefore, the transmission device G for transmitting the power of the electric motor 41 to the steering shaft 42 includes the reduction gear transmission device (gear transmission device) 59, 60, 61, 62 configured by the two-stage gear mechanism of the external gear described above. The reduction gear transmission device is composed of a joint 63 provided with a second large-diameter driven gear (driven gear) 62.

Next, the mounting structure of the steering wheel 10 provided above the control unit U will be described. First, the mounting shaft 66 of the steering wheel 10 is bolted to the upper surface of the second large-diameter driven gear 62 via the flange 66a. Install at 67.

Then, a taper 66b, a serration 66c, and a screw portion 66d similar to the upper end portion of the steering shaft 42 are provided at the upper end portion of the mounting shaft 66 rising upward from the flange 66a, and the hub 10a of the steering wheel 10 is joined to the upper end portion. It is fitted in the same manner as above, and is fastened and attached by the spring washer 64 and the nut 65.

The 66e is a recess provided in the lower part of the mounting shaft 66, and the mounting height of the steering wheel 10 can be lowered by accommodating the upper end portion of the steering shaft 42 in the recess 66e. Further, 10b is a cap, and the cap 10b is mounted after the hub 10a of the steering wheel 10 is mounted on the mounting shaft 66.

Therefore, when the steering wheel 10 is attached to the second large-diameter driven gear 62 via the mounting shaft 66 as described above, the steering wheel 10 is attached to the steering shaft 42 via the second large-diameter driven gear 62 and the joint 63. By combining, it is possible to manually turn the steering wheel 10 to steer the front wheels 8 by using a part of the drive unit D of the automatic steering device as in the conventional case.

The torque for driving the steering shaft 42 by the stepping motor 41 is set to be smaller than the torque for driving the steering shaft 42 by manually turning the steering wheel 10, and the manual operation is configured to take precedence over the automatic operation.

Further, when the automatic control is turned on by the push button 68 of the automatic switch provided in the operation unit C for instructing the on / off of the automatic control, the stepping motor 41 is self-held by the holding torque while the stepping motor 41 is stopped. Since the torque is larger than the steering torque from the steering unit 43 side, the steering angle of the front wheels 8 can be maintained as it is even when the stepping motor 41 is stopped.

Further, if a manual operation is performed by the steering wheel 10 while the automatic control is turned on by the push button 68, the steering control device B forcibly turns off the automatic switch. Therefore, when the energization of the stepping motor 41 is stopped in accordance with the turning off of the automatic switch, the holding torque disappears and the steering wheel 10 can be turned lightly.

The push button 68 is provided on the upper surface of the cover 54 near the rear side close to the driver's seat 28 on the left side when viewed from the driver's seat 28, and the cover 54 in front of the push button 68 is slightly higher in the front-rear direction than the push button 68. Since the convex portion 54a is integrally molded, the convex portion 54a can prevent the push button 68 from being unexpectedly pressed and prevent an erroneous operation of the automatic steering control.

Further, if the upper surface of the cover 54 is traced to the left with the left hand, the position of the push button 68 can be found by tracing the feel of the convex portion 54a. Therefore, the steering wheel 10 is manually operated with the right hand to point the tractor 1 in the target direction. In this state, the push button 68 can be quickly pressed without visually observing the push button 68 to switch to automatic steering control. Further, when the push button 68 is quickly pushed to turn off the automatic steering control in an emergency, it is not necessary to visually confirm the existence of the push button 68 as well.

Next, measures against dust biting of the transmission device G configured by the above-mentioned gear transmission device will be described. As shown in FIG. 6, in the dish-shaped recess 54b provided in the center of the cover 54 that covers the upper surface side of the drive unit D of the control unit U, a circular hole 54c for receiving the outer peripheral portion of the hub 10a of the steering wheel 10 is provided. prepare. Alternatively, when the hub 10a of the steering wheel 10 is provided at a higher position, the hole 54c of the cover 54 is made smaller in diameter so as to receive the outer peripheral portion of the mounting shaft 66.

The cover 54 is fixed to the steering column 29 side, while the hub 10a of the steering wheel 10 rotates with manual steering or automatic steering, and the peripheral edge of the hole 54c of the cover 54 and the outer peripheral portion of the hub 10a rotate relative to each other. Therefore, it is necessary to provide a gap between them to allow relative rotation and prevent damage. Therefore, for example, when dust (foreign matter) such as clothes (sleeve), stone fragments attached to the hand, or sand falls downward due to manual steering operation, the dust (foreign matter) such as sand falls through this gap and onto the transmission device G. There is a risk of falling down, causing transmission problems such as dust biting and failure of the transmission device.

Therefore, it is necessary to take measures to prevent foreign matter from entering the transmission device G. Therefore, a vinyl chloride or soft plastic seal 69 formed in a donut shape is attached to the peripheral edge of the hole 54c of the cover 54 on the back surface side. In this case, if the diameter of the hole 69a of the seal 69 is made smaller than the outer diameter of the hub 10a of the steering wheel 10, when the steering wheel 10 is mounted on the mounting shaft 66, the peripheral edge of the hole 69a of the seal 69 is formed. It is pushed and bent by the outer peripheral edge of the tapered hub 10a of the steering wheel 10, whereby the peripheral edge of the hole 69a of the seal 69 is brought into close contact with the outer peripheral edge of the hub 10a to eliminate the gap.

Further, even if the mounting eccentricity between the seal 69 and the hub 10a or the axial eccentricity of the hub 10a occurs, the seal 69 follows so as to eliminate the gap due to the flexibility of the seal 69, so that foreign matter to the transmission device G is as much as possible. It can be expected that the seal 69 can mute or insulate the meshing sound or the like generated by the transmission device G. However, on the contrary, the seal 69 having such flexibility cannot deny the possibility that dust is forcibly separated and dropped on the transmission device G due to the flexibility.

Therefore, in order to completely prevent foreign matter from entering the transmission device G, a catching body 70 is provided to catch and retain the dust falling on the transmission device G through the gap and the seal 69. Specifically, the capture body 70 is configured by welding an enclosure that rises in an octagonal shape to the upper surface of the flange 66a of the mounting shaft 66 using a plate. Further, the enclosure 70 is inside the enclosure 70 so that the upper end thereof is close to the hole 54c provided in the cover 54 and the inscribed circle of the enclosure 70 is larger than the diameter of the hole 54c. Allows a considerable amount of debris to be retained firmly.

The steering column 29 is provided so as to improve the operability of the steering wheel 10 or to be tilted so as not to hit the knees of the operator sitting on the driver's seat 28, and the upper surface of the flange 66a of the mounting shaft 66 is also provided. It also tilts and rotates. Therefore, it cannot be denied that the dust falling from the upper gap may bounce on the upper surface of the flange 66a and jump out beyond the enclosure 70.

Therefore, a cushion 71 made of a donut-shaped sponge is attached and provided in the enclosure 70 provided on the upper surface of the flange 66a of the mounting shaft 66 so that the intrusion of foreign matter into the transmission device G can be prevented even more completely. .. Therefore, since the momentum of the dust falling from the upper gap is received by the cushion 71 and disappears, the dust can be subsequently retained in the cushion 71 or the enclosure 70 on the outer peripheral side thereof.

Further, the catching body 70 is configured by providing an enclosure on the upper surface of the flange 66a of the mounting shaft 66, and the bottom surface of the catching body 70 can be easily and inexpensively provided by using the upper surface of the flange 66a, and the cushion 71. Even so, the sponge can be punched out and manufactured easily and inexpensively.

It is conceivable that dust may be caught in the meshing portion of the first small-diameter drive gear 59 and the first large-diameter driven gear 60, but since the upper part of this meshing portion is shielded by the cover 54, the dust is bitten. No crowding occurs. Further, if dust collects on the catching body 70 due to long-term use or at the time of regular inspection, if the steering wheel 10 is removed from the mounting shaft 66 and the cover 54 is opened, the dust accumulated on the catching body 70 can be scraped out. Can be done.

Further, as described above, the electronic boards 52 and 53 on which the steering control device B and the operation unit C are mounted are attached to the back surface side of the resin cover 54, but the waterproofness and vibration isolation of these electronic boards 52 and 53 are improved. Therefore, it is protected by injecting urethane resin or the like. In that case, as shown in FIG. 9, a box-shaped rib 54d is integrally molded on the back surface side of the cover 54, and two electronic substrates 52 and 53 are placed at predetermined intervals while being surrounded by the ribs 54d. The resin liquid L is injected into the substrates 52 and 53 surrounded by the ribs 54d.

However, simply pouring the resin liquid L between the two substrates 52 and 53 through the gap between the rib 54d and the substrate 52 takes time and is inferior in workability. Therefore, an expansion portion toward the side wall of the cover 54 is provided at one position of the rib 54d formed in a box shape, and the spout 72 is formed here. If the resin liquid L is poured from the spout 72 between the two substrates 52 and 53, the work time for pouring the resin liquid L can be shortened, and the spout becomes wider as a whole. It is possible to facilitate the resin filling work.

Since a button switch or the like is provided on the surface side of the electronic board 53 on which the operation unit C is mounted, a sponge is provided between the electronic board 53 and the cover 54 so that the resin liquid does not flow into the switch or the like. It is attached and blocked. Further, if the front lower cover 56 provided below the cover 54 toward the driver's seat 28 side is made of hard resin, it may cause pain when the operator's knee or the like hits, or the electronic boards 52 and 53 of the control unit U may be placed. It may vibrate and damage it.

Therefore, if the front lower cover 56 is made of a soft resin, it is possible to alleviate damage to the knees and the like and damage to the electronic substrates 52 and 53. Further, taking advantage of the flexibility of the front lower cover 56, a recess is integrally molded on the outer peripheral edge of the front lower cover 56, and the recess is inserted into the edge of the bracket 51 and the bottom plate 55 to bolt the front lower cover 56 to these. It can be attached without stopping, so that the front lower cover 567 can be easily attached and detached.

Further, when the control unit U is removed for maintenance or when returning to the manual steering device, it may be difficult to pull out the joint 63 which is connected to the steering shaft 42 by taper and serration. In this case, it is integrated with the joint 63. The second large-diameter driven gear 62 may be pulled up by using a gear puller. However, if the gap between the gear 62 and the lower bracket 51 is small, it may be difficult to hook the claws of the gear puller.

Therefore, as shown in FIGS. 10 to 12, two tap holes T1 and T2 are provided in the gear 62, while tap holes J1 are provided in the center thereof, and spacers are provided at both ends in the longitudinal direction thereof. If a simple removal jig J to which the pipe J2 is fixed is prepared, a bolt is passed through the pipe J2 of the removal jig J and screwed into the tap holes T1 and T2 of the gear 62, and also screwed into the tap hole J1 in the center. If the tip of the bolt is brought into contact with the tip of the steering shaft 42 and turned, the joint 63 and the bracket 51 and the like can be easily pulled out from the steering shaft 42 together with the gear 62.

Further, when the joint 63 is fastened to the steering shaft 42 together with the gear 62 with the nut 65, the steering shaft 42 rotates and torque cannot be applied, so that the two cannot be securely fastened. Therefore, by providing holes G1 and G2 in the gear 62 and the bracket 51, respectively, as shown in FIG. 13 (FIG. 11), for example, by passing a round bar Dr such as a screwdriver through the holes G1 and G2, respectively. The gear 62 and the joint 63 are prevented from rotating around the steering column 29 via the bracket 51, and the gear 62 and the joint 63 can be securely fastened to the steering shaft 42 with the nut 65.

Further, when the mounting shaft 66 is fastened to the gear 62 with the bolt 67 and mounted, the gear 62 also rotates and torque cannot be applied. Therefore, by providing a hole G3 in the flange 66a of the mounting shaft 66 as shown in FIG. 14, a round bar Dr is passed through the hole G3, the hole G1 of the gear 62, and the hole G2 of the bracket 51 to prevent the rotation. Therefore, the mounting shaft 66 can be securely fastened to the gear 62 with the bolt 67.

In the above-described embodiment, the capture body 70 is configured by an enclosure provided on the upper surface of the flange 66a of the mounting shaft 66, but the point is that foreign matter does not reach the tooth surface of the second large-diameter driven gear 62. A similar enclosure may be provided on the upper surface of the second large-diameter driven gear 62, or a cup-shaped tray may be attached to the mounting shaft 66.

Further, when the driven gear of the drive unit is provided on the steering shaft as in the prior art document, the capturing body 70 may be provided on the steering shaft, or the capturing body 70 may be provided on the driven gear. Further, the steering control device B, the operation unit C, and the drive unit D are integrated as one control unit U, and this control unit U is attached to the upper part of the steering column 29 that supports the steering shaft 42, but the steering control is provided. The device B and the operation unit C may be provided in a different place from the drive unit D.

Then, the automatic steering device detects the lateral deviation of the vehicle from the captured image to the straight movement or the follow-up of the vehicle by the image processing device A, and gives a steering instruction to the steering control device B. The present invention is not limited to the above-described embodiment because it can be mounted or can be independently controlled to go straight based on the current position of the vehicle.

1 Tractor (working vehicle)
10 Steering wheel 29 Steering column 41 Electric motor (stepping motor)
42 Steering shaft 54 Cover 62 Second large-diameter driven gear (driven gear)
63 Fitting 66 Mounting shaft 69 Seal 70 Capturing body (enclosure)
71 Cushion

Claims (4)

A steering wheel and a drive unit of the automatic steering device are provided above the steering column that supports the steering shaft, and the steering wheel or the drive unit of the automatic steering device rotates the steering shaft to change the traveling direction of the work vehicle. In the steering device, the drive unit of the automatic steering device includes a transmission device that transmits the power of the electric motor to the steering shaft, and a catching body that blocks and catches foreign matter from entering the transmission device. It is composed of a gear transmission device for external gears, a joint for attaching the driven gear of this transmission device is connected to the upper end portion of the steering shaft, and a mounting shaft for connecting the steering wheel to the upper end portion is fixed on the driven gear. A work vehicle characterized in that an enclosure is provided on the upper surface side of the driven gear, and the enclosure constitutes a catching body that prevents foreign matter from entering the transmission device . The steering device for a work vehicle according to claim 1, wherein an enclosure is provided on the upper surface of the flange of the mounting shaft provided on the driven gear, and the enclosure constitutes a catching body that prevents foreign matter from entering the transmission device. .. The steering device for a work vehicle according to claim 2, wherein a cushion is provided in an enclosure provided on the upper surface of the flange of the mounting shaft, and the cushion prevents foreign matter from jumping out of the enclosure. A seal is provided on the cover that covers the upper part of the transmission device, and the gap between the hole formed in the cover and the outer peripheral portion of the hub of the steering wheel or the mounting shaft is closed by this seal to prevent foreign matter from entering the transmission device. The steering device for a work vehicle according to claim 2 or 3, characterized in that.

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