JP2006199211A - Tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tractor capable of securing good the easiness in the steering operation by installing a rotation restricting piece protrusively on a stationary side case forming body, installing a piece with rotation restricted on a knuckle arm, and restricting rotation of a rotary side case forming body. <P>SOLUTION: The tractor is structured so that a front axle case extending to the left and right is installed on a machine body frame and a front left wheel and a front right wheel are installed on the left and right side ends of the front axle case through a left and a right gear case, wherein the left and the right gear case are each formed from a stationary side case forming body installed on the side end of the front axle case and a rotary side case forming body installed on the stationary side case forming body rotatably round the axis stretching in the vertical direction through a knuckle arm 86, and the rotation restricting piece 97 is mounted protrusively on the stationary side case forming body while the piece with rotation restricted 98 is mounted on the knuckle arm 86, whereby the piece 98 is engaged with the piece 97 to restrict rotation of the rotary side case forming body 89 generated through the knuckle arm 86. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tractor.

  Conventionally, as one form of tractor, a front axle case extending in the left-right direction is attached to the body frame, and a pair of left and right front wheels are attached to the left and right end portions of the front axle case via left and right gear cases, respectively. Yes (see, for example, Patent Document 1).

  Each left and right gear case is fixed to the left and right ends of the front axle case, and the fixed case forming body is rotatable about the vertical axis via a knuckle arm. It forms from the attached rotation side case formation body.

  Here, the knuckle arm pivotally supports the base end portion at the upper end portion of the fixed case forming body so as to be rotatable about the vertical axis, and is connected to a connecting piece extending outward from the base end portion. The upper end portion of the moving case forming body is connected by a connecting bolt.

Further, at the front part and the rear part of the outer peripheral surface of the fixed side case forming body, a rotation restricting piece protrudes toward the rotating side case forming body, respectively, while the front part of the outer peripheral surface of the rotating side case forming body And the rear part are provided with a rotation-regulated piece, respectively, and when the steering operation is maximized in either the left or right direction, the rotation-regulated piece at the front part (rear part) is attached to the front part (rear part). The rotation of the rotation side case forming body is restricted by engaging with the rotation restricting piece.
Japanese Patent Publication No. 6-511

  However, in the tractor described above, the rotation of the rotation-side case forming body is restricted between the fixed-side case forming body and the rotation-side case forming body via the rotation restriction piece and the rotation restricted piece. Therefore, when the rotation-side case forming body is restricted from being rotated by the fixed-side case forming body, it is the same as the connecting piece of the knuckle arm that is rotating the rotation-side case forming body. When an excessive shearing force is applied to the connecting bolt that connects the upper end of the rotating side case forming body, the connecting bolt is sheared and the rotating side case forming body cannot be rotated. May occur.

  Therefore, in the present invention, in the tractor in which a front axle case extending in the left-right direction is attached to the body frame, and a pair of left and right front wheels are attached to left and right end portions of the front axle case via left and right gear cases, respectively. The left and right gear cases are a fixed case forming body attached to the side end of the front axle case, and a rotating side that is attached to the fixed case forming body through a knuckle arm so as to be rotatable about a vertical axis. The rotation restricting piece is formed on the fixed case forming body, and the rotation restricting piece is provided on the knuckle arm, and the rotation restricting piece is related to the rotation restricting piece. In addition, the present invention provides a tractor characterized in that the rotation of the rotation-side case forming body via the knuckle arm is restricted.

  The present invention is also characterized in that the rotation restricting piece is provided only at one central portion of the outer peripheral surface of the stationary case forming body in plan view.

  (1) In the first aspect of the present invention, a front axle case extending in the left-right direction is attached to the fuselage frame, and a pair of left and right front wheels are attached to the left and right end portions of the front axle case via left and right gear cases, respectively. In the attached tractor, each left and right gear case can be rotated around an axis in the vertical direction via a knuckle arm and a fixed case forming body attached to the side end of the front axle case. A rotation-side case forming body attached to the fixed-side case forming body, and a rotation-regulating piece provided on the knuckle arm. The rotation of the rotation side case forming body through the knuckle arm is restricted by engaging with the rotation restriction piece.

  In this way, while the rotation restricting piece protrudes from the fixed case forming body, the rotation restricted piece is provided on the knuckle arm, and the rotation restricted piece is engaged with the rotation restricting piece. Since the rotation of the rotation-side case forming body via the knuckle arm is restricted, even when the knuckle arm and the rotation-side case forming body are connected by the connection bolt, the connection bolt is directly connected to the connection bolt. In other words, an excessively large shear force does not act.

  Therefore, shearing of the connecting bolt can be prevented, and the steering operability can be ensured satisfactorily.

  (2) In the present invention described in claim 2, the rotation restricting piece is provided only at one central portion of the outer peripheral surface of the stationary case forming body in plan view.

  In this way, since the rotation restricting piece is provided only at one central portion of the outer peripheral surface of the fixed case forming body in plan view, the left and right gear cases can be shared, and the manufacturing cost Can be reduced.

  A shown in FIG. 1 is a tractor according to the present invention. The tractor A is provided with a prime mover unit 2 on an airframe frame 1, and a transmission unit 4 is linked to the prime mover unit 2 via a clutch unit 3. The PTO transmission 5 is detachably linked to the rear part of the transmission unit 4, and the driving unit 6 is disposed on the transmission unit 4. The front axle case 7 is disposed below the fuselage frame 1. A pair of left and right front wheels 8 and 8 are linked and connected, while a pair of left and right rear wheels 10 and 10 are linked and connected to the transmission unit 4 via rear axle cases 9 and 9.

  As shown in FIG. 1, the prime mover unit 2 has an engine 15 mounted on the machine frame 1, a radiator 16 is disposed immediately in front of the engine 15, and a battery 17 is disposed in front of the radiator 16. Further, a fuel tank 18 formed by extending in the front-rear direction is disposed at a position directly above the engine 15, and these are covered with a bonnet 19 so as to be freely opened and closed. 20 is a muffler.

  As shown in FIGS. 2 and 3, the clutch unit 3 includes a traveling clutch 22 and a PTO clutch 23 disposed close to each other in a coaxial manner in the clutch housing 21 to form a dual clutch mechanism.

  As shown in FIGS. 2 and 3, the mission unit 4 is housed in a mission case 24 that extends in the front-rear direction and is formed in a cylindrical shape. The mission case 24 is a main transmission case that incorporates a main transmission mechanism. 25, a sub-transmission case 26 incorporating a sub-transmission mechanism, and a differential case 27 incorporating a differential mechanism 42 (see FIG. 8).

  A power take-out portion 28 is provided at the left front portion of the transmission unit 4. An air compressor 29 is detachably attached to the front end portion of the power take-out portion 28, while a hydraulic pressure is applied to the rear end portion of the power take-out portion 28. The pump 30 is detachably attached.

  Here, as shown in FIGS. 2 and 3, a hydraulic filter 32 and a hydraulic oil tank 33 are connected in series to the hydraulic pump 30 via a hydraulic pipe 31, and the hydraulic pump 30 and the hydraulic filter are connected to each other. 32 and the hydraulic oil tank 33 are arranged close to each other.

  Further, as shown in FIGS. 2 and 3, a lever base case 34 is provided in communication with the ceiling of the auxiliary transmission case 26, and a lever interlocking mechanism (not shown) provided in the lever base case 34 is provided. The base end portions (lower end portions) of the main transmission lever 35 and the sub transmission lever 36 are interlocked and connected.

  As shown in FIGS. 1 and 2, a front wheel drive power take-out case 37 is communicated with the bottom of the auxiliary transmission case 26, and the front wheel power built in the front wheel drive power take-out case 37 is connected. While the output shaft 38 protrudes forward from the take-out mechanism (not shown), the input shaft 40 (see FIG. 5) faces rearward from the front wheel drive mechanism 39 (see FIG. 4) provided in the front axle case 7. A transmission shaft 41 (see FIG. 1) extending in the front-rear direction is interposed between both shafts 38 and 40.

  As shown in FIG. 8, the differential case 27 is provided with a differential mechanism 42 therein, and the differential mechanism 42 has a base end portion (inner end portion) of a pair of left and right output shafts 110, 110 having an axis line in the left-right direction. Are connected to each other so that the front end portions (outer end portions) of the output shafts 110 and 110 protrude outward from the left and right side walls 27a and 27a of the differential case 27. Reference numeral 111 denotes a differential lock operation mechanism that differentially locks the differential mechanism 42, and a differential lock pedal (not shown) disposed in the operation unit 6 is linked to the differential lock operation mechanism 111.

  As shown in FIG. 2, a lift arm support 49 is detachably attached to the ceiling portion of the differential case 27, and a hydraulic circuit body 50 is detachably attached to the front of the lift arm support 49. At the rear of the lift arm support 49, the base ends of a pair of left and right lift arms 52, 52 are attached via a lift arm support shaft 51, and the middle of each lift arm 52, 52 and the left and right of a PTO transmission case 53 to be described later Lift cylinders 54, 54 that extend and contract in the vertical direction are interposed between the lower portion of the side walls.

  As shown in FIG. 2, the PTO transmission unit 5 has a PTO transmission case 53 linked to the rear wall portion of the differential case 27 of the transmission unit 4, and the PTO transmission mechanism is provided in the PTO transmission case 53. A PTO transmission mechanism (not shown) that constitutes a part of the PTO transmission mechanism is provided, and a PTO shaft 55 that forms a terminal portion (rear end portion) of the PTO transmission mechanism is protruded rearward.

  As shown in FIG. 1, the operation unit 6 erects a dashboard 60 so as to close the rear end opening of the bonnet 19 provided in the prime mover unit 2, and places a meter panel 61 on the upper end of the dashboard 60. The steering wheel support shaft 62 protrudes upward from the meter panel 61, and the steering wheel 63 is attached to the upper end of the steering wheel support shaft 62. The driver's seat 64 is arranged in the upper position.

  1 to 3, a cover body 65 is stretched over the driving section 6, the mission section 4, and the left and right rear wheels 10, 10, and the step section of the driving section 6 is moved by the cover body 65. While forming, the upper part of the mission part 4 is coat | covered.

  As shown in FIGS. 4 and 5, the front axle case 7 includes a central case forming body 70, and left and right case forming bodies in which respective base end portions are connected to left and right end portions of the central case forming body 70. 71 and 71, and the base end portions of the left and right case forming bodies 71 and 71 are adjustable in the mounting position around the axis with respect to the left and right end portions of the central case forming body 70.

  That is, the central case forming body 70 forms circular communication port portions 73, 73 on the left and right side portions of the forming body main body 72 that houses the front wheel drive mechanism 39, and the outside of each communication port portion 73, 73. A plurality of (8 in the present embodiment) bolt holes 75, 75 functioning also as positioning holes by forming end faces as butting faces 74, 74, with a constant spacing in the circumferential direction on each abutting face 74, 74. Forming.

  The left and right case forming bodies 71 and 71 are formed in the same shape and are shared, and are connected to the base end portions (inner end portions) of the cylindrical forming body bodies 76 and 76 extending in the left-right direction. The flange portions 77 and 77 are formed, the outer end surfaces of the connecting flange portions 77 and 77 are formed as butted surfaces 78 and 78, and the bolt holes 75 and 75 are formed in the peripheral portions of the connecting flange portions 77 and 77. A plurality of (8 in the present embodiment) bolt insertion holes 79, 79 that coincide with each other are formed.

  In this manner, the abutting surfaces 78, 78 of the left and right case forming bodies 71, 71 are brought into surface contact with the abutting surfaces 74, 74 of the central case forming body 70, and the bolt holes 75, 75 The left and right case forming bodies 71 and 71 are connected to the central case forming body 70 by aligning the bolt insertion holes 79 and 79 and screwing the connecting bolts 80 into both the holes 75 and 79. Case 70 can be formed.

  At this time, by adjusting the mounting position by rotating the left and right case forming bodies 71, 71 around the axis with respect to the bolt holes 75, 75 formed in the respective butting surfaces 74, 74 of the central case forming body 70. The bolt insertion holes 79 formed in the connecting flange portions 77 and 77 of the left and right case forming bodies 71 and 71 can be matched, and a predetermined caster angle θ can be provided as shown in FIG. it can.

  In this way, the base end portions of the left and right case forming bodies 71 and 71 can be adjusted around the axis with respect to the left and right end portions of the central case forming body 70, so that each left and right side can be adjusted. There is no need to attach the left and right gear cases 81, 81, which will be described later, to the front ends of the case forming bodies 71, 71 via taps, and as a result, the left and right gear cases 81, 81 can be shared, The manufacturing cost can be reduced accordingly.

  Further, as shown in FIGS. 4 and 5, the left and right case forming bodies 71 and 71 are fixedly provided with lower ends of cylinder stays 82 and 82 extending in the vertical direction, respectively. Further, a power steering cylinder 83 forming a part of a power steering mechanism (not shown) is interposed.

  Here, the power steering mechanism is linked to a steering wheel 63 provided in the driving unit 6, and the power steering mechanism is connected to left and right front wheels 8, via left and right gear cases 81 and 81, which will be described later. 8, the front wheels 8 and 8 can be steered by the steering wheel 63 via the power steering mechanism and the left and right gear cases 81 and 81.

  The power steering cylinder 83 passes through a cylinder body 84 extending in the left-right direction and a piston rod 85 extending in the left-right direction in the cylinder body 84, and slides the piston rod 85 in the left-right direction by hydraulic pressure. The left and right end portions 85a, 85a of the piston rod 85 are linked to knuckle arms 86, 86 described later.

  In this way, the power steering cylinder 83 is interposed in the left and right case forming bodies 71 and 71 via the cylinder stays 82 and 82, respectively. The mounting accuracy of the power steering cylinder 83 can be increased by the abutment surfaces 74, 74, 78, 78 with the base ends of the left and right case forming bodies 71, 71, and the assembly work of the power steering cylinder 83 can be simplified. Can do.

  In addition, connecting flange portions 87 and 87 are formed on the front end portions (outer end portions) of the left and right case forming bodies 71 and 71 configured as described above. The right gear cases 81 and 81 are connected, and the front wheels 8 and 8 are attached to the left and right gear cases 81 and 81, respectively.

  That is, the left and right gear cases 81, 81 are formed of a fixed case forming body 88, 88 and a rotating case forming body 89, 89, and the fixed side case forming body 88, 88 extends in the vertical direction. The connecting flange portions 91, 91 are connected to the inner side walls of the forming body bodies 90, 90 to be connected, and the connecting flange portions 91, 91 are connected to the front end portions (outer end portions) of the left and right case forming bodies 71, 71. Are connected and fixed to connecting flange portions 87 and 87 by connecting bolts 92 and 92.

  Further, the rotation-side case forming bodies 89, 89 are provided with connecting boss portions 94, 94 connected to the outer walls of the forming body bodies 93, 93 extending in the vertical direction. The front axles 95 and 95 of the front wheels 8 and 8 are pivotally connected and connected.

  Further, as shown in FIG. 6, the base end portions (rear end portions) of the knuckle arms 86, 86 extending in the front-rear direction are formed on the upper end portions of the forming body bodies 90, 90 of the fixed case forming members 88, 88. 86a and 86a are pivotally supported and connected so as to be rotatable about the vertical axis, and from the base end portions 86a and 86a toward the upper end portions of the forming body bodies 93 and 93 of the rotating case forming bodies 89 and 89, respectively. The connecting pieces 86b, 86b are extended so that the front ends of the connecting pieces 86b, 86b are connected to the upper ends of the formed body bodies 93, 93 by connecting bolts 96, 96, and the fixed case forming members 88, 88 The lower end portions of the forming body bodies 90, 90, 93, 93 of the rotating side case forming bodies 89, 89 are pivotally connected to each other.

  In this way, the rotation-side case forming bodies 89 and 89 are attached to the fixed-side case forming bodies 88 and 88 through the knuckle arms 86 and 86 so as to be rotatable about the vertical axis.

  Further, as shown in FIGS. 6 and 7, the rotation regulating pieces 97, 97 are provided at the center portions of the outer peripheral surfaces of the forming body bodies 90, 90 of the fixed case forming bodies 88, 88. While projecting toward the outer side, which is the 89 side, on the front side of the lower surface of the connecting pieces 86b, 86b of the knuckle arms 86, 86, the rotationally regulated pieces 98, 98 are provided on the fixed case forming body 88, 88 side. It protrudes toward a certain inside.

  In this way, the rotation-regulated pieces 98, 98 rotate integrally with the rotation-side case forming bodies 89, 89, and engage with the rotation-regulating pieces 97, 97 so that the knuckle arms 86, 86 are The rotation of the rotation-side case forming bodies 89 and 89 is restricted.

  Therefore, even when the knuckle arms 86, 86 and the rotation side case forming bodies 89, 89 are connected by the connecting bolts 96, 96, a shearing force exceeding the allowable value directly acts on the connecting bolts 96, 96. There is nothing.

  As a result, the connecting bolts 96, 96 can be prevented from being sheared, and the steering operability can be secured satisfactorily.

  Moreover, since the rotation restricting pieces 97 and 97 are provided only at one central portion of the outer peripheral surface of the forming body main bodies 90 and 90 of the fixed side case forming bodies 88 and 88 in a plan view, FIG. As shown in FIG. 5, when the steering wheel 63 is steered to the right as much as possible, the right rotation side case forming body 89 is connected to the rotation restricting piece 97 provided on the right fixed side case forming body 88. 7 is engaged to restrict the rotation of the rotation-side case forming bodies 89 and 89, while the steering wheel 63 is set to the maximum leftward as shown in FIG. When the steering operation is limited, the rotation restricting piece 98 provided on the left rotation side case forming body 89 is engaged with the rotation restricting piece 97 provided on the left fixed case forming body 88. Thus, the rotation of the rotation side case forming bodies 89, 89 is restricted.

  As a result, the left and right gear cases 81 and 81 can be shared, and the manufacturing cost can be reduced.

  In FIG. 4, 100 is a front wheel drive shaft, 101 is a drive bevel gear, 102 is an intermediate vertical axis, 103 is an input side bevel gear, 104 is an output side bevel gear, and 105 is a front axle input bevel gear.

  As shown in FIGS. 8 and 9, the rear axle cases 9, 9 are formed of cylindrical case bodies 116, 116 extending in the left-right direction, and casing bodies 117, 117 integrally formed on the front upper portions of the case bodies 116, 116, It is attached to the left and right side walls 27a, 27a of the differential case 27. Reference numeral 147 denotes an input shaft.

  The rear axles 48, 48 are inserted into the case bodies 116, 116, and the rear axles 48, 48 are rotatably supported. Input gears 112, 112 are attached to the base ends of the rear axles 48, 48. On the other hand, output gears 113 and 113 are attached in the middle of the output shafts 110 and 110, and the input gears 112 and 112 are engaged with the output gears 113 and 113, respectively.

  Further, in each casing body 117, multi-plate brake devices 114, 114 are interlocked and connected, and the configuration of the brake device 114 will be described below with reference to FIGS.

  That is, as shown in FIGS. 8 to 12, the brake device 114 has a plurality of (this embodiment) that rotate integrally with the output shaft 110 on the outer peripheral surface of the tip end portion (outer end portion) of the output shaft 110. The three rotation-side discs 115 are attached.

  Then, as shown in FIG. 12, a plurality of (two in this embodiment) locking recesses 118, 118 are formed on the inner surface of the casing body 117 that covers the rotating disk 115, with the output shaft 110 as the center. A plurality (two in this embodiment) of locking pieces are arranged on the peripheral edge of a plurality of (three in the present embodiment) fixed-side discs 119, which are arranged at symmetrical positions. The fixed-side discs 119 are formed by projecting 120, 120 at point-symmetrical positions around the output shaft 110 and fitting and locking the respective locking pieces 120, 120 in the locking recesses 118, 118. Are positioned and supported by the casing body 117, and each fixed disk 119 is fixed around the output shaft 110.

  Further, on the outer side of the rotating side disk 115, a pivot recess 122 is formed in the side wall 121 portion of the casing body 117 located on the same axis as the output shaft 110, and the pivot support recess 122 is pressed. The body 123 is pivotably supported.

  That is, the pressing action body 123 includes a cylindrical action body support shaft 124 that is fitted to the pivot support recess 122 so as to be rotatable about its axis, and a disk integrally formed on the outer peripheral surface of the action body support shaft 124. Shaped action body 125.

  An engagement recessed portion 126 is provided on the outer surface of the action main body 125, while an engagement piece 128 is provided at an inner end portion of the rotation operation shaft 127 pivoted through the side wall 121 of the casing body 117 in the left-right direction. The engaging piece 128 is engaged with the engaged recess 126, and an operating arm 129 is connected to the outer end of the rotation operation shaft 127, and the operating unit is connected to the operating arm 129. A brake pedal 130 (see FIGS. 1 and 2) provided in FIG.

  Further, as shown in FIGS. 10 to 12, a plurality (three in this embodiment) of rotating cam ball guide grooves 131 are provided along the circumferential direction in the outer peripheral edge portion of the working body 125. It is provided at intervals.

  On the other hand, on the inner side surface of the side wall 121 of the casing body 117 as the fixed side portion, the fixed side cam ball guide groove 132 is formed so as to face the respective rotation side cam ball guide grooves 131, and the fixed side cam ball guide grooves 132 and the above described Cam balls 133 are interposed between the respective rotation side cam ball guide grooves 131 in an engaged state.

  Further, on the inner side of the rotation side disk 115, a receiver mounting step 143 is formed on the inner peripheral wall 142 of the casing body 117 located on the same axis as the output shaft 110, and the receiver mounting step is performed. The peripheral portion of the disk receiver 144 formed in a donut plate shape on the step 143 is fixed by a fixing bolt 145, and the disk receiver 144 is arranged to face the pressing action body 123 with the disks 115 and 119 interposed therebetween. Yes. Reference numeral 146 denotes a bearing.

  In this way, when the brake pedal 130 is depressed, the rotation operation shaft 127 is rotated clockwise through the operating arm 129 in the side view shown in FIG. The pressing body 123 is rotated clockwise through 126.

  Then, the pressing action body 123 rotates on the same axis as the output shaft 110, thereby interlocking with the cam ball 133 moving in the circumferential direction along the fixed side cam ball guide groove 132 and the rotation side cam ball guide groove 131. Then, the pressing action body 123 is moved in the thrust direction that presses both the rotating side disk 115 and the fixed side disk 119 toward the disk receiver 144 side.

  As a result, the rotation-side disk 115 and the fixed-side disk 119 are brought into surface contact with the disk receiver 144 in a pressed state, and the rotation of the output shaft 110 is braked.

  Moreover, as shown in FIG. 11, the fixed cam ball guide groove 132 is a conical concave portion having a tapered surface 135, while the rotating cam ball guide groove 131 is a bowl-shaped concave portion having a tapered surface 134. And a regulating portion 148 that regulates the movement of the cam ball 133 on the tapered surface 134, and the inclination angle α1 of the tapered surface 135 of the fixed cam ball guide groove 132 is equal to that of the tapered surface 134 of the rotating cam ball guide groove 131. It is formed larger than the inclination angle α2.

  Here, the rotation-side cam ball guide groove 131 formed as a bowl-shaped recess forms a conical tapered surface 134 at the bottom, and forms a cylindrical surface continuously with the peripheral edge of the tapered surface 134, The cylindrical surface serves as a restriction portion 148.

  The restricting portion 148 is disposed inward of the outer peripheral edge 149 of the tapered surface 135 of the fixed cam ball guide groove 132.

  Therefore, when the pressing action body 123 is rotated on the same axis as the output shaft 110, the cam ball 133 is formed in the both guide grooves 131, 132, and the gap between the tapered surfaces 134, 135 is between the opposed tapered surfaces 134, 135. Guided and moved in a narrower direction.

  When the movement of the cam ball 133 on the tapered surface 134 is restricted by the restricting portion 148 provided in the rotating cam ball guide groove 131, the cam ball 133 is pressed against the tapered surface 135 of the fixed cam ball guide groove 132. It causes a wedge effect.

  As a result, the pressing action body 123 is moved in the thrust direction, and the pressing action body 123 presses both the disks 115 and 119 so that the brake braking is reliably performed.

  At this time, the fixed-side cam ball guide groove 132 is a conical concave portion, while the rotating-side cam ball guide groove 131 is merely a bowl-shaped concave portion, so that the cam ball 133 reliably presses the pressing body 123. In order to ensure that the pressing body 123 presses both discs 115 and 119, the rotational cam ball guide groove 131 is processed as compared with the conventional case where the rotational cam ball guide groove is formed in a teardrop-shaped concave shape. High accuracy and assembly accuracy of the pressing body 123 are not required, and the manufacturing cost can be reduced.

  In addition, the cam ball 133 is restricted from moving on the tapered surface 134 by the restricting portion 148 of the rotation-side cam ball guide groove 131, but the interval between the fixed side cam ball guide groove 132 and the tapered surface 135 becomes narrow. Since the amount of movement in the thrust direction of the pressing body 123 with respect to the rotational angle of the pressing body 123 can be secured large, the rotational angle of the pressing body 123 can be increased. The stroke of the brake pedal to be determined can be held at an appropriate amount.

  Further, since the inclination angle α1 of the tapered surface 135 of the fixed cam ball guide groove 132 is larger than the inclination angle α2 of the taper surface 134 of the rotation side cam ball guide groove 131, the rotation of the pressing action member 123 is performed. An even greater amount of movement of the pressing body 123 in the thrust direction with respect to the angle can be ensured.

  Since the restricting portion 148 is disposed inward of the outer peripheral edge 149 of the tapered surface 135 of the fixed cam ball guide groove 132, the cam ball restricted by the restricting portion is tapered on the tapered surface of the fixed cam ball guide groove 132. And the wedge effect can be ensured satisfactorily.

  As a result, the pressing action body is moved in the thrust direction, and the braking effect generated by the pressing action body pressing both disks can be ensured satisfactorily.

  In addition, in order to compensate for the insufficient braking force, there is no need to increase the number of rotating side disks 115 and fixed side disks 119, and the installation space of the brake device 114 can be kept compact.

  Further, as shown in FIG. 10, the spring receiving piece 136 is formed on the inner peripheral surface of the action body supporting shaft 124 of the pressing action body 123, while the stepped small diameter portion 137 is formed at the tip of the output shaft 110, A thrust bearing 138 as a rotational force non-transmission means is provided on the outer peripheral surface of the stepped small diameter portion 137, and a pressing spring 139 as an elastic means is interposed between the side surface of the thrust bearing 138 and the spring receiving piece 136. I am letting.

  In this way, the pressing spring 139 elastically biases the pressing member 123 in the direction opposite to the thrust direction pressing the rotating side disk 115 and the fixed side disk 119, and the pressing spring 139 and the output shaft. A thrust bearing 138 interposed between the output shaft 110 and the pressure spring 139 prevents the rotational force from being transmitted to the pressure spring 139.

  Accordingly, since the rotational force is not transmitted from the output shaft 110 to the pressing spring 139 by the thrust bearing 138, the pressing spring 139 does not rotate.

  As a result, in the spring receiving piece 136 that is a contact portion between the pressing spring 139 and the pressing action body 123, heat generation due to friction can be prevented, and a good braking performance can be ensured.

  Further, as shown in FIGS. 9 and 12, a lower communication path 140 that extends in the vertical direction and communicates with the case body 116 is formed in the lower portion of the casing body 117, and at the rear portion of the casing body 117 in the front-rear direction. An upper communication path 141 that extends and communicates with the case main body 116 is formed.

  Then, the oil level of the lubricating oil accommodated in the rear axle case 9 is set at a position above the lower communication path 140 and below the upper communication path 141, as seen from the side view of FIGS. Lubricant flowing in the inflow direction b into the casing body 117 through the lower communication path 140 by rotating the rotation-side disk 115 integrally with the output shaft 110 that rotates in the clockwise rotation direction a. The oil is scooped up by the rotating disk 115 that rotates, and the lubricating oil that has been scooped up flows out in the outflow direction c through the upper communication path 141 and returns into the case main body 116.

  In this way, by applying lubricating oil to the rotating side disk 115 and the fixed side disk 119, the frictional heat generated between the both disks 115, 119 is cooled, and the brake braking function by the both disks 115, 119 is ensured satisfactorily. To be able to.

Side surface explanatory drawing of the tractor which concerns on this invention. Side surface explanatory drawing of the latter half part of the tractor. Plane explanatory drawing of the latter half part of the tractor. Front explanatory drawing of a front axle case. Side surface explanatory drawing of the center part case formation body of the front axle case. The partially cutaway plan view of the left gear case. Operation | movement explanatory drawing of the left and right rotation side gear case formation body. Side surface explanatory drawing of a differential case and a rear axle case. Sectional back surface explanatory drawing of the differential case and a rear axle case. The cross-sectional rear view of a brake device. The partial expanded sectional rear view of a brake device. Side surface explanatory drawing of the brake device.

Explanation of symbols

A Tractor 1 Airframe frame 2 Motor part 3 Clutch part 4 Mission part 5 PTO transmission part 6 Driving part 7 Front axle case 8 Rear axle case 9 Front wheel
10 rear wheels

Claims (2)

In a tractor with a front axle case that extends in the left-right direction attached to the fuselage frame, and a pair of left and right front wheels attached to the left and right side ends of the front axle case via left and right gear cases,
Each left and right gear case has a fixed case forming body attached to the side end portion of the front axle case, and a rotation that is attached to the fixed side case forming body through a knuckle arm so as to be rotatable around an axis in the vertical direction. Formed from a side case forming body,
While the rotation restricting piece protrudes from the fixed case forming body, the rotation restricted piece is provided on the knuckle arm, and the rotation restricted piece is engaged with the rotation restricting piece via the knuckle arm. A tractor characterized in that the rotation of the rotation-side case forming body is restricted.   The tractor according to claim 1, wherein the rotation restricting piece is provided only at one place on a central portion of the outer peripheral surface of the fixed case forming body in plan view.

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