JP2014034384A - Transmission device of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a small-sized and compact transmission structure by rationally disposing a PTO shaft in a transmission case and providing an optionally stopped clutch mechanism.SOLUTION: In a working vehicle, the power of an engine E is input to a shift input shaft 22 in a transmission case 21 through a main clutch 23, and the input power drives wheels 3, 4 of a traveling vehicle body 2 after being shifted by variable speed gears 26, 27 in the transmission case 21. The shift input shaft 22 and a PTO shaft 24 are coaxially disposed, and the rotation of the shift input shaft 22 is transmitted to the PTO shaft 24 through a PTO clutch mechanism 48. The front side of the shift input shaft 22 elongated forward and backward is journaled to the transmission case 21, the short PTO shaft 24 is supported on the transmission case 21, and a boss-like part 24a is formed on the PTO shaft 24 to which the end of the shift input shaft 22 is journaled.

Description

  The present invention relates to a transmission device for a work vehicle such as an agricultural tractor and a riding management machine, and more particularly to an improvement of a transmission device having a PTO shaft.

  Conventionally, Patent Document 1 is an example of a transmission device for a riding-type work vehicle equipped with a transmission device for a riding management machine, that is, a field management work device such as a chemical spreader. According to this patent document 1, as shown in FIG. 17, the traveling mission device a is connected so as to be able to be transmitted by a transmission shaft d that constitutes a traveling transmission path c connected to the traveling clutch b, and the traveling power is input. It is said. The traveling transmission device a is internally provided with a main transmission device e, an auxiliary transmission device f, etc., and outputs to the traveling output shaft g and the rear PTO shaft h. In this case, the rear PTO shaft h is configured to output from the lower transmission side of the main transmission device e and the sub-transmission device f, so that the output can be changed and is suitable for a work machine that requires a shifting operation during work. ing. On the other hand, transmission to the control pump k is performed via the PTO shaft j. The configuration is such that a pulley k is provided on the transmission shaft d and a belt n is hung between the pulleys m of the driven PTO shaft j. The belt n is provided with a tension pulley p so as to be able to act as a clutch. Therefore, transmission to the control pump k by the PTO shaft j can be arbitrarily stopped by a clutch action, and when the work machine is connected to the rear PTO shaft h, this can be stopped and output. Eliminate waste.

JP 2010-195096 A

  However, the PTO shaft configuration of the work vehicle shown in Patent Document 1 is such that a rear PTO shaft h and a PTO shaft j for a control pump are prepared in advance, and the PTO shaft j of the control pump can be arbitrarily stopped. However, as a PTO transmission device for a dedicated work machine without simultaneous work, it is unnecessary to construct one PTO shaft of two systems in this way because one is unnecessary. In addition, because the power entering the transmission from the engine is branched and transmitted to the PTO shaft that is placed at the rear of the vehicle body, there is no choice but to have a long transmission structure of the PTO shaft, and there is room for improvement in terms of light weight and compactness. .

  In view of the above, the present invention seeks to obtain a compact and compact transmission configuration while rationally arranging the PTO shaft in the mission case and also having a clutch mechanism that arbitrarily stops.

  According to the first aspect of the present invention, the rotational power from the engine E is input to the transmission input shaft 22 in the transmission case 21 via the main clutch 23, and the input rotational power is input to the transmissions 26 and 27 in the transmission case 21. In the transmission device of the working vehicle that drives the wheels 3 and 4 of the traveling vehicle body 2 by shifting the speed of the traveling vehicle body 2, the shift input shaft 22 and the PTO shaft 24 are arranged coaxially, and the PTO clutch is rotated by the rotation of the shift input shaft 22. The transmission device for the work vehicle is configured to rotate the PTO shaft 24 via the mechanism 48.

  By providing the PTO clutch mechanism 48 between the transmission input shaft 22 that receives engine power via the main clutch 23 and the PTO shaft 24, the PTO shaft 24 can be used even if the main clutch 23 is engaged. 48 can be selected as ON / OFF, and the operator can select and set the drive state / non-drive state of the PTO shaft 24 arbitrarily.

  According to a second aspect of the present invention, in the first aspect, the front side of the transmission input shaft 22 that is long in the front-rear direction is pivotally supported by the transmission case 21, the short dimension PTO shaft 24 is supported by the transmission case 21, and the PTO shaft 24 is A boss-like portion 24a is formed, and the rear end of the speed change input shaft 22 is pivotally supported by the boss-like portion 24a.

  As a result, the front side of the transmission input shaft 22 that is long in the front-rear direction is pivotally supported with respect to the transmission case 21, and the short-sized PTO shaft 24 is supported on the transmission case 21, so that one end of the transmission input shaft 22 is connected to the PTO shaft 24. It is supported and the structure of the shaft support to the mission case 21 can be omitted.

  According to a third aspect of the present invention, in the second aspect of the present invention, the PTO clutch mechanism 48 is configured so that the gear shift input is applied to the internal gear clutch 24b formed on the inner periphery of the front end of the boss-shaped portion 24a of the PTO shaft 24 coaxial with the gear shift input shaft 22. The clutch body 48a that is slidably supported by the spline portion formed at the rear portion of the shaft 22 is engaged and disengaged. Originally, the rear end portion of the transmission input shaft 22 is pivotally supported by the boss-like portion 24a, so that a special support configuration is not required for the transmission case 21, and the configuration can be simplified and the cost can be reduced.

  According to a fourth aspect of the present invention, in the first aspect, the transmission input shaft 22 and the counter shaft 25 are provided in parallel to the transmission input shaft 22, and the transmission gear group provided between the counter shaft 25 and the input transmission shaft 22. The transmissions 26 and 27 that change the speed according to the selection are configured, and the front wheels 3 or the rear wheels 4 are driven by the transmission output of the transmissions 26 and 27 by the rotational power of the transmission input shaft 22. Therefore, regardless of whether the transmissions 26 and 27 are provided, the selection of the transmissions 26 and 27 does not affect the rotation of the transmission input shaft 22 and the PTO shaft 24.

  According to a fifth aspect of the present invention, the first transmission 26 and the second transmission 27 are provided in the fourth aspect. The invention described in claim 6 is the structure according to any one of claims 1 to 5, wherein the PTO shaft 24 is connected to the control pump 10 of the chemical spraying device.

  According to the first aspect of the present invention, even if the main clutch 23 is engaged, the PTO shaft 24 can select the PTO clutch mechanism 48 to be turned on or off, and the operator can arbitrarily set the PTO shaft 24 in a driven state or a non-driven state. Since it can be selected and set, the working device can be stopped even during traveling.

  In addition to the effect of the first aspect, the invention according to the second aspect has a simple structure because one end portion of the transmission input shaft 22 is supported by the PTO shaft 24 and the support structure to the transmission case 21 can be omitted. And can be configured inexpensively.

  In addition to the effect of the second aspect, the invention according to the third aspect has an internal gear clutch 24b formed on the inner periphery of the front end of the boss-like portion 24a at the front end of the PTO shaft 24 and a rear portion of the transmission input shaft 22. Since the clutch body 48a supported by the spline portion is engaged and disengaged, and the rear end portion of the transmission input shaft 22 is originally supported by the boss-like portion 24a, a special support structure is provided for the transmission case 21. The cost can be reduced by simplifying the configuration without the need for

  In addition to the effect of the first aspect, the invention according to claim 4 selects the transmission devices 26 and 27 regardless of whether the transmission input shaft 22 includes part of the transmissions of the transmission devices 26 and 27. 22 and the rotation of the PTO shaft 24 are not affected, a constant rotation can be obtained before and after the shift switching by the transmissions 26 and 27, and the workability can be maintained without any fluctuation in the rotation of the work implement.

Whole side view of chemical spraying work vehicle Front view of a chemical spraying vehicle Rear view of chemical spraying work vehicle Top view of a chemical spraying work vehicle Front view showing spraying condition Side cross-sectional view of the transmission mechanism Front view around the transmission mechanism Plan view around the transmission mechanism Plan view with partial cross section of front axle and steering cylinder mechanism AA sectional view of FIG. Rear cross-sectional view of left front wheel transmission section (A), rear view of final case (B) Plan sectional view (A) of steering shaft case, partially enlarged side view of connecting member Schematic rear view showing the fixed state of the left front wheel tie rod and ball joint Plan view showing steering and interlocking states of front and rear wheels Side view showing steering and interlocking states of front and rear wheels Rear cross-sectional view of left rear wheel transmission Transmission configuration explanatory diagram showing an example of conventional technology

  Hereinafter, a chemical solution spraying vehicle as an embodiment of the working vehicle of the present invention will be described with reference to the drawings. When there is a pair of left and right components, the symbol L indicates the left side and the symbol R indicates the right side.

  FIG. 1 is a side view of a working vehicle for spraying chemicals according to the present invention. FIG. 2 is a front view of the chemical spraying work vehicle according to the present invention. 1 and 2 show a state in which left and right spraying booms, which will be described later, are housed on both left and right side surfaces of the traveling vehicle body. On the other hand, FIG. 3 is a front view showing a state where the chemical solution spraying vehicle according to the present invention is spraying the chemical solution.

  As shown in FIGS. 1 and 2, the traveling vehicle body 2 of the chemical spraying work vehicle 1 is provided with a pair of left and right front wheels 3L and 3R and a pair of left and right rear wheels 4L and 4R. Is attached with a control spraying device 11.

As shown in FIG. 2, in the chemical solution spraying work vehicle 1 of the first embodiment, the minimum ground height H is high and the inter-wheel distance (tread) W is wide.
An engine E covered with a bonnet 5 is mounted above the pair of left and right front wheels 3L, 3R of the traveling vehicle body 2. A pilot seat 6 is provided above the pair of left and right front wheels 3L, 3R and the pair of left and right rear wheels 4L, 4R, and a handle 7 is provided in front of the pilot seat 6.

  When the steering wheel 7 is steered to the left and right, as will be described later, the pair of left and right front wheels 3L and 3R and the pair of left and right rear wheels 4L and 4R are simultaneously interlocked and steered in the opposite phase, so that a four-wheel steering configuration is possible. .

A chemical tank 9 is detachably provided so as to surround the cockpit 6, and a control pump 10 is provided below the cockpit 6.
Further, as shown in FIG. 4, the control spraying device 11 includes a center spraying boom 11C located in front of the machine body, and left and right side spraying booms 11L and 11R provided on the left and right sides of the center spraying boom 11C. .

  The control spraying device 11 is moved up and down by the lifting cylinder 15 (see FIG. 1), and the left and right side spraying booms 11L and 11R are independently protruded left and right by the open / close levers 17L and 17R (see FIG. 4). (See FIG. 5) and the vehicle body 2 is housed in a state along both sides of the traveling vehicle body 2 (see FIGS. 1 to 4).

  And the chemical | medical solution of the chemical | medical solution tank 9 is sent to the control spraying apparatus 11 by the control pump 10, and a chemical | medical solution sprays from the spray nozzles 14,14 ... provided in multiple numbers by the center spraying boom 11C and the left and right side spraying booms 11L, 11R. (See FIGS. 1 and 5).

  Next, a speed change transmission mechanism that receives power from the engine E and transmits the speed change power to each part will be described with reference to FIGS. A main clutch 23 is interposed between the output shaft 20 supported coaxially with the crankshaft (not shown) of the engine E and the transmission case 21 side transmission input shaft 22. The main clutch 23 has a known configuration in the form of a multi-plate clutch, and is configured such that the power in the normally connected state is interlocked with each other by stepping on the clutch pedal 23 a disposed in the step portion below the cockpit 6.

  The power passing through the main clutch 23 is linked to the transmission mechanism in the transmission case 21 via the speed change input shaft 22, and this transmission case 21 is configured to join the front and rear case portions 21f and 21r. The structure is such that various transmission shafts and the like are supported on the bearing wall portions around 21.

  The transmission input shaft 22 extends rearward and is supported in the transmission case 21 to form a transmission transmission shaft, and is provided with a plurality of transmission gears. The transmission input shaft 22 and a coaxial PTO shaft 24 are supported on the rear wall portion of the transmission case portion 21r, and a bearing is provided on the boss-like portion 24a at the front end to support the rear end of the transmission input shaft 22. . In this embodiment, the PTO shaft 24 is provided exclusively for driving the control pump 10 to be described later, and the input pulley 12 of the control pump 10 provided below the cockpit 6 from the pulley 31 at the shaft end can be belt-transmitted as described later. doing.

  A first counter shaft 25 is provided in parallel with the speed change input shaft 22. Then, by selecting a transmission gear group provided between the first counter shaft 25 and the input transmission shaft 22, a three-stage auxiliary transmission 26 serving as a first transmission is configured, and a second transmission is performed. A main transmission 27 that can select a forward-side high / low-second speed and a back-first speed is configured as a device. The power from the speed change input shaft 22 passes through the gear stage shifted by the first speed change device 26 (hereinafter referred to as the sub-transmission device 26), and then is transmitted by the second speed change device 27 (hereinafter referred to as the main speed change device 27). This is a configuration in which the front wheels 3 and the rear wheels 4 are driven through either one of the two forward speeds or the first speed of the back speed.

  That is, the auxiliary transmission 26 mainly accommodated in the rear case portion 21r of the transmission case 21 is provided with three auxiliary transmission gears 28a, 28b, and 28c fixed to the transmission input shaft 22 and having different gear diameters. A sub-transmission sliding gear 29 for selecting the sub-transmission gears 28a to 28c is provided on the counter shaft 25 side, and a large-diameter gear 29b of the two-stage gears of the sliding gear 29 meshes with the sub-transmission gear 28b. The small-diameter gear 29c meshes with the auxiliary transmission gear 28c, and the smallest-diameter small gear 29a formed integrally with the boss portion 29d of the sliding gear 29 is supported by the first counter shaft 25 so as to be freely rotatable. It is the structure which meshes with the internal gear part 30a of the counter gear 30 which always meshes with 28a. Since it is configured in this way, the auxiliary transmission first gear is obtained by sliding the auxiliary transmission sliding gear 29 and meshing the smallest diameter gear 29a with the internal gear portion 30a of the counter gear 30. The sub-shift second speed is obtained by meshing the large-diameter gear 29b of the step gear with the sub-transmission gear 28b, and the sub-transmission third speed is achieved by meshing the small-diameter gear 29c of the two-stage gear with the sub-transmission gear 28c. obtain.

  The boss portion 29d and the two-stage gear of the auxiliary transmission sliding gear 29 are separately formed, and the pawl clutch portion 29e is assembled in a constantly meshing state so as to be slidably fitted to a spline formed on the first counter shaft 25. I am letting.

  A main transmission device 27 is provided in a portion of the transmission case 21 accommodated in the front case portion 21f. The sub-shifted driving force of the first countershaft 25 is transmitted to the second countershaft 35 by selecting the main shift height, the second speed and the back speed.

  In other words, the back speed intermediate gear 36 is loosely fitted to the front end portion of the first counter shaft 25, and the low speed intermediate gear 37 is loosely fitted to the front side of the counter gear 30 on the auxiliary transmission 26 side. The main transmission sliding gear 38 that is slidable by being fitted to the spline portion of the second counter shaft 35 includes an internal gear 38b for the back speed and an intermediate internal gear 38c for the low speed centered on the high speed intermediate gear 38a. Formed back and forth. Further, a forward counter gear 39 is pivotally supported on the speed change input shaft 22 so as to be able to rotate independently of the rotation of the speed change input shaft 22. The counter counter gear 39 for normal rotation is formed with a counter gear 39a for low speed and a counter gear 39b for high speed having different diameters.

  The forward counter gear 39c formed integrally with the boss portion of the forward counter gear 39 is always meshed with the forward transmission gear 40 of the second counter shaft 35, and the back speed intermediate gear 36 is also a second gear. This is a configuration that always meshes with the transmission gear 41 for the back speed of the counter shaft 35.

  When the low-speed intermediate internal gear 38c of the main transmission sliding gear 38 is fitted to the low-speed intermediate gear 37, the sub-shifted rotational power of the first counter shaft 25 is converted to the low-speed intermediate gear 37, the low-speed counter gear. The forward transmission gear 40 is driven via the forward rotation counter gear 39c to transmit the low speed forward rotation power to the second counter shaft 35. When the high-speed intermediate gear 38a of the main transmission sliding gear 38 is engaged with the high-speed counter gear 39b, the power of the first counter shaft 25 passes through the high-speed intermediate gear 38a, the high-speed counter gear 39b, and the forward counter gear 39c. Then, the normal transmission gear 40 is driven to transmit high-speed normal rotation power to the second counter shaft 35.

  Further, when the back speed internal gear 38b of the main transmission sliding gear 38 is fitted to the back speed intermediate gear 36, the main-shifted rotational power of the first counter shaft 25 becomes the back speed intermediate gear 36, The speed transmission gear 41 is driven to transmit the back speed power to the second counter shaft 35.

  The main / sub-transmission driving force of the second countershaft 35 is transmitted to the travel transmission shaft 44 via the deceleration intermediate transmission gear groups 42 and 43. The traveling transmission shaft 44 projects forward and backward of the transmission case 21, and the rear spline shaft portion 44a drives the rear wheels 4L and 4R via the rear axle by interlocking with the rear wheel differential mechanism via the rear transmission shaft 44r. The spline shaft portion 44b on the side drives a front wheel differential mechanism 58, which will be described later, via the front transmission shaft 44f to drive the front wheels 3 and 3.

  The main transmission lever 46 of the main transmission device 27 and the auxiliary transmission lever 47 of the auxiliary transmission device 26 are provided on the left side of the cockpit 6 and can be shifted along a front-rear guide guide. The right side of the cockpit 6 is provided with a PTO lever 49 for switching a PTO clutch mechanism 48 disposed on the PTO shaft 24 between on and off.

  That is, the PTO clutch mechanism 48 is a clutch supported by an internal gear clutch 24b formed on the inner periphery of the front end of the boss-like portion 24a at the front end of the PTO shaft 24 and a spline portion formed on the rear portion of the transmission input shaft 22. A body 48a is provided, and the clutch body 48a is configured to engage and disengage the clutch body 48a with the internal gear clutch 24b as the shifter 48b moves back and forth. The shifter 48 b is configured to interlock with the PTO lever 49. The shifter stay 48c to which the shifter 48b is fixed is supported by the transmission case 21 so as to be reciprocally slidable in parallel with the transmission input shaft 22, and an interlocking link 48d is provided on the rear end side of the shifter stay 48c that protrudes rearward from the transmission case 21. Via the base end of the PTO lever 49. The PTO lever 49 has a base end side 49a rotatably attached to one side of the pair of left and right traveling frames 2L and 2R constituting the traveling vehicle body 2 (the right traveling frame 2R side in the illustrated example), and is gripped to be bent. The portion side 49b is provided so as to be swingable back and forth with the mounting base side 49a as an axis, and the meshing clutch mechanism 48 is entered by swinging forward and the reverse swinging operation is performed backward. The engagement clutch mechanism 48 is cut (FIG. 7).

  Brake means 45 is provided on a metal portion 21m that is detachably fastened and fixed to the rear wall of the transmission case 21 on the rear side of the traveling transmission shaft 44. The brake unit 45 is configured to brake the travel transmission shaft 44 by pressing a multi-plate brake shoe against the wall surface of the metal portion 21m. As a result, the front, rear, left and right four wheels are braked at once.

  As described above, the PTO shaft 24 is disposed behind the transmission case 21 by being provided coaxially with the main clutch 23, and the pulley 12 at the rear end of the shaft protruding rearward from the rear wall of the transmission case 21 is provided on the side. This is a configuration in which the pump 10 is driven by belt transmission to the pulley 31 of the approaching control pump 10. The control pump 10 is fixed by brackets 32 and 32 that have a size extending between the pair of travel frames 2L and 2R, and the body portion 10a is erected on the left travel frame 2L.

  By providing the PTO clutch mechanism 48 between the speed change input shaft 22 that receives engine power via the main clutch 23 and the PTO shaft 24, the control pump 10 can be operated even if the main clutch 23 is engaged. The PTO clutch mechanism 48 can be interlocked by 49 operations, and the operator can select and set the pump drive state / non-drive state arbitrarily.

  The PTO clutch mechanism 48 is supported by an internal gear clutch 24b formed on the inner periphery of the front end of the boss-like portion 24a at the front end of the PTO shaft 24 provided coaxially with the speed change input shaft 22, and a spline portion formed at the rear portion of the speed change input shaft 22. The clutch body 48a is engaged and disengaged with the forward and backward movement of the shifter 48b. Since the boss-like portion 24a originally supports the rear end of the transmission input shaft 22, the transmission case 21 does not require a special support structure, and the structure can be simplified and the cost can be reduced.

  A first transmission device is provided by selecting a transmission input shaft 22 and a first counter shaft 25 in parallel with the transmission input shaft 22 and selecting a transmission gear group provided between the first counter shaft 25 and the input transmission shaft 22. , And the second transmission, and after the power of the transmission input shaft 22 passes through the gear stage shifted by the first transmission 26, the second transmission 27 shifts forward high speed or low speed. Since the front wheels 3 and the rear wheels 4 are driven through the steps, the first and second transmissions are configured, but the shift output does not affect the rotation of the shift output shaft 22 and the PTO shaft 24.

  As shown in FIGS. 6 and 8, a clutch housing 34 that covers the casing 23 a of the main clutch 23 is provided. The clutch housing 34 is formed in a U shape in a plan view, and bases 34 a and 34 a are detachably mounted on the front wall of the transmission case 21, and a bearing portion 34 b is formed on a wall portion formed on the front side. The main clutch 23 body appears on the upper and lower surfaces, but the upper surface is covered with a thin plate member not shown. The bearing portion 34b supports the output shaft 20 that is linked to the crankshaft of the engine E. If comprised in this way, the support structure of the output shaft 20 will become integral with the mission case 21, and the improvement of the precision will be achieved when the main clutch 23 is assembled | attached.

  As shown in FIG. 7 and the like, the transmission case 21 is mounted on the traveling vehicle body 2 with a pair of left and right traveling frames 2L and 2R integrally provided with base members 2B and 2B, and the base members 2B and 2B. The transmission case 21 is fastened from the side.

Next, the front wheel transmission mechanism and the steering mechanism will be described with reference to FIGS.
Here, FIG. 9 is a schematic plan view of a partial cross section of the front axle housing, and FIG. 10 is a schematic view showing the AA cross section of FIG.

A front axle housing 51 that houses a front axle 50 and the like for transmitting driving force to the pair of left and right front wheels 3 and 3 is disposed below the front side of the traveling vehicle body 2.
A cylindrical boss portion 51A that supports a front wheel input shaft 52 that is linked to the travel transmission shaft 44 via a front transmission shaft 44f is formed at the center rear portion of the front axle housing 51. The bevel gear 52a interlocks with a front wheel differential mechanism 53 disposed at the center of the axle housing 51. A front axle 50 extending left and right from the front wheel differential mechanism 53 is connected to a steering shaft 55 of a steering shaft case 54 connected to left and right ends of the axle housing 51 by bevel gears 56 and 57. Here, the bevel gear 56 is provided at the end portion of the front axle 50, and the bevel gear 57 is a driven bevel gear of the bevel gear 56 and is supported on the steering shaft 55.

  As shown in FIG. 11, the steering shaft case 54 includes an outer fitting portion to the terminal end side of the axle housing 51, a cylindrical upper portion 54 a that is connected via a flange of the axle housing 51 and protrudes upward, and a lower portion. A conical portion 54b formed so as to gradually become smaller in diameter and a cylindrical lower portion 54c that includes a bearing 58 and rotatably supports the final case 59 around the steering shaft 55. Bevel gears 56 and 57 from the end of the front axle 50 to the steering shaft 55 are provided. The final case 59 includes a front wheel shaft 66 that supports the right front wheel 3 and includes a bevel gear 60 at the lower end of the steering shaft 55 and a driven bevel gear 61 that meshes therewith. The final case 59 includes a fitting portion 59a for fitting the lower portion of the steering shaft case 54 to the outside and a side surface portion 59b for connecting the driven bevel gear 61 to the outside surface of the fitting portion 59a.

  The steering shaft 55 of the steering shaft case 54 is provided in an inclined state so that the lower end side is directed outward from the vehicle body with respect to the vertical line, and the final case 59, the transmission mechanism such as an internal bevel gear and the front wheel 3 are inclined. The shaft 55 is provided so as to be rotatable.

  A boss portion 54d is formed on the top of the cylindrical upper portion 54a of the steering shaft case 54, and a rotating member 62 and a final case 59 that are rotatably fitted to the boss portion 54d via a sleeve are provided. The steering shaft case 54 is detachably connected by a connecting member 63 in a suspended manner. An annular portion 63a is formed in the middle of the connecting member 63 in the vertical direction, and is externally fitted to the conical portion 54b of the steering shaft case 54. In other words, the flange-like annular portion 63a is rotatably fitted to the outside of the conical portion 54b via a sleeve. A knuckle arm 64 for rotating and steering the final case 59 in conjunction with a steering cylinder mechanism described later is attached to the upper surface of the annular portion 63a.

  The upper and lower positions of the annular portion 63a of the connecting member 63 are directly below the portion where the thickness is large due to the pivotal support of the driven bevel gear 57 attached to the upper portion of the steering shaft 55. Of these, it is fitted to a relatively strong part. Therefore, the steering force from the steering cylinder mechanism transmitted through the knuckle arm 64 is received in a concentrated manner. However, since the connecting member 63 forms an annular member 63a and is fitted to the steering shaft case 54, the knuckle arm Since the steering load transmitted to 64 is shared and received by the steering shaft case 54, deformation and distortion of the connecting member 63 are prevented. In addition, by arranging the position of the annular member 63a in the vicinity of the thickened portion for the bearing portion that supports the steering shaft 55 and the bevel gear 57 of the steering shaft case 54, the above-described steering load is received. Since the reinforcing structure is exhibited, the conical portion 54b that does not directly receive the steering load can be formed as thin as possible.

  The front side surface 63af of the annular portion 63a has an inclined surface shape that is inclined by a predetermined angle β toward the left front wheel 3L side with respect to the traveling direction F of the traveling vehicle body 2. Further, the knuckle arm 64 fixed to the upper surface of the annular portion 63a is fixed with an inclination of a predetermined angle γ toward the left front wheel 3L side, similarly to the front side surface 63af of the annular portion 63a, with respect to the traveling direction F. (FIG. 12A).

  In agricultural work vehicles where the minimum ground height H needs to be as high as possible, it is necessary to make the structure so as not to obstruct as much as possible so as not to damage the crop. Since the crop flows smoothly in the lower part of the traveling vehicle body 2, the crop is hardly damaged.

  On the other hand, the knuckle arm is conventionally attached with an offset from the final case. However, the knuckle arm is either a rotatable rotating member provided on the upper part of the steering shaft case or a connecting member. When the height H is high, there is a problem in that the structure of each part for rotating the final case is subjected to strong bending stress and is easily damaged.

  On the other hand, according to the above configuration of the present embodiment, the upper side of the steering shaft case 54 has a height at which the knuckle arm 64 is disposed, and the annular portion 63a is not provided near this height. Further, unnecessary bending stress can be prevented from being applied to the connecting member 63 for rotating the final case 59. Further, by making the steering shaft case 54 into a substantially conical shape whose diameter decreases from the cylindrical upper portion 54a downward, the annular portion 63a and the lower cylindrical portion 54c can be configured with a small number of parts at low cost. Further, since the connecting member 63 and the annular portion 63a are integrated, this structure can be configured with a small number of parts and at a low cost.

Next, the configuration of the steering cylinder mechanism that steers the left and right front wheels and the rear wheels in conjunction with each other will be described.
A steering cylinder mechanism 70 for steering the pair of left and right front wheels 3L, 3R is disposed in front of the front vehicle body 2 at the front lower side of the traveling vehicle body 2. The piston rod 71 of the steering cylinder mechanism 70 is connected to the knuckle arms 64L and 64R via tie rods 72L and 72R, respectively. When pressure oil is supplied to one side of the steering cylinder mechanism 70, the piston rod 71 extends to the left side, the knuckle arm 64L is rotated to the left via the tie rod 72L, and the left front wheel 3L is turned to the left (solid arrow in FIG. 8). . At this time, as the piston rod 71 moves, the right tie rod 72R is pulled to pull the knuckle arm 64R, and the right front wheel 3R is also turned to the left (dotted line arrow). The tie rods 72L and 72R are connected to the left and right ends of the piston rod 71 by ball joints 73L and 73R, respectively. The knuckle arms 64L and 64R are rotatably connected to a pair of left and right tie rods 72L and 72R by a pair of left and right ball joints 74L and 74R.

  FIG. 12B shows a configuration for attaching the knuckle arm 64 to the annular portion 63a. A vertical mounting portion 64 a is added to the base of the knuckle arm 64 by means such as integral molding or welding, and is fixed to the base of the knuckle arm 64 with vertical bolts 67 and horizontal bolts 68. With this configuration, the knuckle arm 64 can be firmly attached to the connecting member 63 without loosening of the bolt.

  In FIG. 10, a cylinder portion 70a of the steering cylinder mechanism 70 is a sheet metal member bent in a channel shape, and a cylinder housing 75 in which about half of the outer peripheral surface of the cylindrical body of the cylinder portion 70a is accommodated and fixed in a concave portion thereof. Is provided.

  Further, in the center of the cylinder housing 75, a cylindrical fitting portion 76 extending rearward, that is, toward the front axle housing 51 is integrally provided by a welding structure in the illustrated example. The inside of the cylindrical fitting portion 76 is formed in a cylindrical internal space. On the other hand, in the center of the front axle housing 51, a cylinder that fits outwardly to a cylindrical fitting portion 76 provided in the cylinder housing 75 forward of a cylindrical boss portion 51A that supports the front wheel input shaft 52. The shape fitting boss portion 51B is integrally formed. And after the said cylindrical fitting part 76 is inserted in the cylindrical fitting boss | hub part 51B, the connection part is penetrated and fixed by the fixing pin 77 which is a fastening member for anti-detachment and rotation prevention. Yes.

  As described above, a front and rear pair of front axle housing 51 is provided with a front and rear cylindrical fitting boss 51B and a rear cylindrical boss 51A, which are supported pivotably about the axis X. The support metals 78A and 78B are firmly attached by bolts and nuts, respectively. The end surfaces of the support metals 78A and 78B on the side away from the front axle housing 51 are small diameter portions, and the regulation end surfaces 78a and 78b formed by the small diameter portions are used as the cylindrical boss portion 51A and the cylindrical fitting. By facing the rear end surface and the front end surface of the combined boss portion 51B, the front axle housing 51 can be prevented from shifting in the front-rear direction.

  In order to control the movement amount of the piston rod 71 of the steering cylinder mechanism 70, hydraulic hoses 79L and 79R for supplying and discharging hydraulic oil to and from the left chamber or the right chamber, which are spaces arranged on the left and right sides of the piston, are provided. The front support metal 78B is connected to the cylinder portion 70a of the steering cylinder mechanism 70 via the left and right sides.

Next, a connection structure between the pair of left and right knuckle arms 64L and 64R and the pair of left and right tie rods 72L and 72R will be further described with reference to FIGS.
FIG. 13 is a schematic rear view for explaining a fixed state between the tie rod 72L connected to the left front wheel 3L side and the ball joint 74L.

  As shown in FIG. 11A, the central axis B of the steering shaft 55 is inclined inward by an angle α with respect to the vertical line D. On the other hand, the steering cylinder mechanism 70 and the tie rods 72L and 72R In this embodiment, the ball joints 74L and 74R used to connect the tie rods 72L and 72R and the knuckle arms 64L and 64R are inclined by an angle α as shown in FIG. The tie rods 72L and 72R are fixed to the distal ends. This inclination angle α coincides with the angle formed by the central axis B of the steering shaft 55 shown in FIG. With this configuration, the movement of the steering cylinder mechanism 70 is smoothly transmitted to the left and right front wheels 3L and 3R via the tie rods 72L and 72R, the ball joints 74L and 74R, the knuckle arms 72L and 72R, and the like.

  By the way, in the conventional configuration, the ball joint which is straightly fixed to the tie rod and disposed horizontally is disposed perpendicular to the pivot shaft (see the steering shaft 55 in FIG. 11) which is originally inclined. In order to connect the knuckle arm, it is necessary to make a part of the shape of the knuckle arm itself into an oblique shape in accordance with the connection surface with the ball joint. Therefore, conventionally, the left and right knuckle arms have different shapes.

  However, according to the configuration described above, the ball joints 74L and 74R themselves are inclined by the angle α as shown in FIG. 13, so that the knuckle arms 64L and 64R can have the same shape on the left and right. The number of mold points and the types of parts can be reduced.

In the above-described configuration described with reference to FIGS. 11 and 13, the description has been made centering on the left front wheel 3 </ b> L side. However, since the configuration is the same on the right front wheel 3 </ b> R side, description thereof is omitted.
The above-described configuration centered on the pair of left and right front wheels 3L and 3R is basically applied in the same manner to the pair of left and right rear wheels 4L and 4R. As shown in FIG. 16, a steering shaft case 86 is attached to the left and right of a rear axle housing 88 that houses the rear axle 92, and the steering shaft 87 is pivotally supported in an inclined posture. A final case 93 is rotatably supported around the steering shaft 87 at the lower portion of the steering shaft case 86. At the top of the steering shaft case 86 is provided a rotating member 80 that can rotate around the axis of the steering shaft 87, and the rotating member 80 and the final case 93 are connected by a connecting member 89. Like the connecting member 63 of the front wheel 3, the connecting member 89 is configured with an annular portion 89 a into which the steering shaft case 86 is fitted in the middle with the same configuration as the connecting member 63 and the annular portion 63 a on the front wheel 3 side.

  The driving force from the rear axle 92 reaches the rear wheel 4 through the steering shaft 87 and the rear wheel shaft 94 in the final case 93 in combination with the transmission by the bevel gear mechanism. Further, bevel gears 95 and 96 sets between the rear axle 92 and the steering shaft 87 and bevel gears 97 and 98 sets between the steering shaft 87 and the rear wheel shaft 94 are configured.

Next, based on FIG. 14 and FIG. 15, an interlocking configuration by steering the front wheels 3 and the rear wheels 4 will be described.
The lid-like turning member 62 is extended to form a front and rear tie rod interlocking arm 65 for steering and interlocking the front and rear wheels. At this time, in the front wheels 3L and 3R, the interlocking arms 65L and 65R are both formed to extend inward of the traveling vehicle body 2 as shown in FIG. On the other hand, the interlocking arms 81L and 81R extending to the lid-like rotating members 80L and 80R of the rear wheels 4L and 4R are formed to extend outward of the traveling vehicle body 2.

  The interlock arm 65L of the left front wheel 3L and the interlock arm 81L of the left rear wheel 4L are connected by the front and rear tie rods 82L, and the interlock arm 65L of the left front wheel 3L and the interlock arm 81L of the left rear wheel 4L are connected by the front and rear tie rods 82L. . With this configuration, when the left and right front wheels 3L and 3R are steered to the left, the left and right rear wheels 4L and 4R are steered to the right via the front and rear tie rods 82L and 82R, resulting in a four-wheel steering state. A small left turn is possible (solid arrow in FIG. 14). Conversely, when the left and right front wheels 3L and 3R are steered to the right, the left and right rear wheels 4L and 4R are steered to the left and can turn right by a small amount (dotted arrows in the figure).

  The front and rear tie rods 82 </ b> L and 82 </ b> R extend rearward and outward from the front axle housing 51, pass through the lower front side of the chemical tank 9, and reach the rear axle housing 86. Of these, the left front and rear tie rods 82L extend back and forth via the support portion of the lifting step 85 on the left side of the traveling vehicle body 2.

  Each connection of the front and rear tie rods to the interlocking arm is performed by a ball joint. That is, the interlocking arms 65L and 65R of the front wheels 3L and 3R project the connecting part side such as the arms of the ball joints 83L and 83R on the upper ends of the arms 65L and 65R, and the interlocking arms 81L of the rear wheels 4L and 4R. , 81R project the arm joint connecting side of the ball joints 84L, 84R below the tip of the arms 81L, 81R. Therefore, the front end sides of the front and rear tie rods 82L and 82R are connected to the upper surface side of the interlocking arms 65L and 65R, while the rear end sides are connected to the lower surface side of the interlocking arms 81L and 81R. As described above, the central axis B of the steering shaft 55 of the steering shaft case 54 is provided so as to be inclined with respect to the vertical line D by the angle α so that the lower end side is directed outward of the vehicle body. The steering shaft case 86 is also configured so that the central axis of the steering shaft 87 in the interior is inclined, so that the front wheel 3L, 3R side interlocking arm 65L, 65R is in the lower position, and the rear wheel 4L, 4L side interlocking arm. 81L and 81R become high, and the arrangement of the ball joints as described above makes the front and rear tie rods 82L and 82R substantially horizontal (FIG. 15), which is advantageous for securing a high position of the lowest ground clearance, and the chemical tank 9 Further, it is possible to facilitate the configuration for avoiding interference with the constituent members constituting the traveling vehicle body 2 such as the lifting step 85 and the lifting step 85. Therefore, troubles due to the interference can be prevented.

  By the way, the rotating member 62 and the interlocking arm 65 on the front wheel 3 side are integrally formed, but the same shape as the integrally formed product of the rotating member 80 and the interlocking arm 81 on the rear wheel 4 side is used to reduce the production cost. I am trying. That is, the bolt insertion hole 63b for connecting the front wheel side connecting member 63 is necessary at a position symmetrical to the interlocking arm 65 of the rotating member 62 (FIG. 11A), while the bolt insertion of the rear wheel side connecting member 89 is performed. Although the hole 89b is necessary at the base of the interlocking arm 81 (FIG. 16), the integrally formed product of the pivoting member and the interlocking arm is manufactured in the same shape on both the front wheel 3 side and the rear wheel 4 side, and it depends on each mounting position. The bolt insertion hole 63b or 88b is drilled. The bolt insertion holes 63b and 89b can be processed together in advance. In this case, the man-hour for managing the number of parts can be reduced.

  The front axle housing 51 swings about the traveling direction axis X with respect to the traveling vehicle body 2, but one rear axle housing 88 is mounted integrally with the traveling vehicle body 2. However, the left and right errors can be absorbed by the connection by the ball joints 83L, 83R, 84L, 84R.

  The steering shaft cases 86L and 86R connected to the left and right sides of the rear axle housing 88 are the same as the steering shaft cases 54L and 54R connected to the front axle housing 51.

  The interlocking arm 65 on the front wheel 3 side and the interlocking arm 81 on the rear wheel 4 side are substantially located in the projection planes of the front axle housing 51 and the rear axle housing 88, respectively, in plan view when the steering handle is in a straight traveling state. Is formed. When the vehicle body is inspected and maintained, the vehicle body is lifted by a crane, and a band or rope lifting band 90 is wound around the front axle housing 51 or the rear axle housing 88. In this case, since it is configured as described above, when the steering handle is set in a straight line and the lifting belt 90 is wound, the interlocking arms 65 and 81 are held in the straight movement state by the lifting belt 90, together with the crane lifting. Even if the wheels 3 and 4 become free and try to rotate around the steering shaft by their own weight, this is prevented, and the front wheels 3 and the rear wheels 4 can maintain a substantially straight traveling state, and the unexpected front and rear wheels 3 and 4 can be maintained. Inspection work can be performed safely without unbalanced load due to rotation. Reference numeral 91 denotes a wedge body that restricts swinging of the front axle housing due to its own weight. Normally, the wedge body 91 is removed, but when performing maintenance, the wedge body 91 is driven into a gap to restrict swinging of the front axle housing 51. .

E engine 10 control pump 21 mission case 22 speed change input shaft 23 main clutch 24 PTO shaft 24a boss-like portion 24b internal gear clutch 26 first transmission (sub transmission)
27 Second transmission (main transmission)
48 PTO clutch mechanism 48a Clutch body

Claims (6)

  Rotational power from the engine (E) is input to the transmission input shaft (22) in the transmission case (21) through the main clutch (23), and this input rotational power is input to the transmission (26) in the transmission case (21). 27), the gear shift input shaft (22) and the PTO shaft (24) are arranged coaxially in a transmission device for a work vehicle that drives the wheels (3, 4) of the traveling vehicle body (2). A transmission device for a work vehicle configured to rotate the PTO shaft (24) via the PTO clutch mechanism (48) by the rotation of the transmission input shaft (22).   The front side of the transmission input shaft (22), which is long in the front and rear directions, is pivotally supported by the transmission case (21), the short dimension PTO shaft (24) is supported by the transmission case (21), and the PTO shaft (24) has a boss-like portion. The transmission device for a work vehicle according to claim 1, wherein the rear end of the speed change input shaft (22) is pivotally supported by the boss-shaped portion (24a).   The PTO clutch mechanism (48) is connected to the internal gear clutch (24b) formed on the inner periphery of the front end of the boss-like portion (24a) of the PTO shaft (24) coaxial with the transmission input shaft (22). The transmission device for a work vehicle according to claim 2, wherein the clutch body (48a) slidably supported by a spline portion formed at a rear portion is engaged and disengaged.   A speed change input shaft (22) and a counter shaft (25) are provided in parallel with the speed change input shaft (22), and a speed change is made by selecting a speed change gear group provided between the counter shaft (25) and the input speed change shaft (22). The transmission (26, 27) is configured to output, and the front wheel (3) or the rear wheel (4) is driven by the transmission output of the transmission (26, 27) with the rotational power of the transmission input shaft (22). The transmission device for a work vehicle according to claim 1.   The transmission device for a work vehicle according to claim 4, comprising a first transmission (26) and a second transmission (27).   The transmission device for a work vehicle according to any one of claims 1 to 5, wherein the control pump (10) of the chemical solution spraying device is driven by the PTO shaft (24).

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