JP2006341664A - Tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To share right and left differential shafts by disposing a pinion shaft center of a pinion gear orthogonal to the differential output shafts at the center of right and left directions of a transmission case, thereby reducing manufacturing cost. <P>SOLUTION: This tractor comprises a differential device 15 having a pair of the right and left differential output shafts 20 in a transmission case, and a pair of right and left brake devices 22 to which the right and left differential shafts 20 are coupled on right and left sides of the transmission case 7, respectively. The pinion shaft center of the pinion gear 41 orthogonal to the differential output shafts 20 is disposed at the center of a right-and-left direction of the transmission case. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tractor having a differential device.

Conventionally, there is one disclosed in Patent Document 1 as a tractor having a differential device.
The tractor of Patent Document 1 is provided with a differential device having a pair of left and right differential output shafts in a mission case, and a pair of left and right brake devices to which the left and right differential output shafts are connected on the left and right outer sides of the mission case. The pinion shaft of the differential device is arranged so as to be closer to the left side than the center portion in the left-right direction of the mission case.
JP-A-6-257647

In the conventional tractor, the pinion shaft of the differential device is shifted to the left side in the left-right direction of the transmission case. Therefore, the distance between the differential device and each left and right brake device is different between the left side and the right side. When connecting with a differential output shaft, separate differential output shafts having different lengths are required, resulting in a high manufacturing cost.
Therefore, in view of the above problems, the present invention can be used for the left and right differential output shafts by arranging the pinion shaft center of the pinion gear orthogonal to the differential output shaft at the center in the horizontal direction of the transmission case, thereby reducing the manufacturing cost. It aims at providing the tractor which can be reduced.

In order to achieve the above object, the present invention takes the following technical means. That is, in the tractor provided with a differential device having a pair of left and right differential output shafts in the transmission case, and provided with a pair of left and right brake devices to which the left and right differential output shafts are respectively connected to the left and right side portions of the transmission case, the differential output shaft The pinion axis of the pinion gear orthogonal to the center of the transmission case is located at the center in the left-right direction.
According to this, since the distance from the pinion shaft to the left and right brake devices can be the same on both the left and right sides, and the lengths of the left and right differential output shafts can be made the same. It can be shared, and the manufacturing cost can be reduced.

A cylinder part for disposing the piston of the brake device is formed on the left and right side walls of the transmission case, and a bearing part for supporting the differential case of the differential apparatus is formed inward of the cylinder part. The differential lock pin for stopping the differential operation of the differential device is arranged between the differential case and the differential case.
According to this, the brake device forming the cylinder portion of the brake device on the left and right side walls of the transmission case can be made compact, and the inner volume of the transmission case sandwiched between the brake devices can be made large. In the meantime, by arranging the differential lock pin for stopping the differential operation of the differential device, the space in the mission case can be effectively utilized, and the pinion shaft can be easily arranged in the center in the left-right direction of the mission case.

The differential device includes a pinion gear supported by the pinion shaft and housed in a differential case, and a differential side gear meshing with the pinion gear, the differential case having an insertion hole into which a differential lock pin is inserted, and the differential side gear Is provided with an engaging recess for engaging the differential lock pin.
According to this, by inserting the differential lock pin into the insertion hole and locking it in the engagement recess, the differential side gear and the differential case rotate together in a state where the differential side gear meshes with the pinion gear. The operation of the device can be stopped.

A collar is provided between the inner surface of the differential case and the end surface of the pinion gear facing the inner surface, a tongue piece that bends toward the differential case is formed on the outer periphery of the collar, and a collar is formed on the inner surface of the differential case. It is in the point which has the latching recessed part which latches a tongue piece part.
According to this, it is possible to prevent the rotation of the collar with a simple configuration.

  According to the present invention, by arranging the pinion shaft center of the pinion gear orthogonal to the differential output shaft at the center in the left-right direction of the transmission case, the left and right differential output shafts can be shared, and the manufacturing cost can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show a tractor according to the present invention. Hereinafter, the traveling direction of the work vehicle is referred to as the front-rear direction, and the direction orthogonal to the front-rear direction is referred to as the left-right direction (left hand side and right hand side as viewed in FIG. 1).
As shown in FIG. 3, the tractor 1 is a two-shaft, four-wheel type having left and right front wheels 2 used for steering and auxiliary driving and left and right rear wheels 3 used for main driving. The drive can be switched to two-wheel drive (rear wheel drive) or four-wheel drive (front / rear wheel drive). An axle 13 (hereinafter, front axle) of the front wheel 2 is rotatably supported by a front axle frame 14 disposed in front of the engine 5.

A mission case 7 is arranged behind the engine 5, and a traveling vehicle body 6 is constituted by these. A hydraulic device 9 having a lift arm 8 is provided at the rear portion of the traveling vehicle body 6. Various working machines (for example, a tiller) are detachably mounted on the rear portion of the hydraulic device 9.
A PTO shaft 12 protrudes from the rear part of the transmission case 7, and the power from the engine 5 is transmitted to the PTO shaft 12, so that the power is transmitted to the working machine attached to the rear part via the PTO shaft 12. It has become. A differential device 15 is provided in the rear portion of the transmission case 7, and the power from the engine 5 is transmitted to the differential device 15, and the power is transmitted to the axle 16 of the rear wheel 3 (hereinafter, rear axle) via the differential device 15. Is transmitted to the rear axle 16 so as to rotate.

As shown in FIG. 1, the differential device 15 is provided with a pair of left and right differential output shafts 20 (brake shafts). The differential output shaft 20 extends outwardly from the left and right side walls 21 </ b> L and 21 </ b> R of the transmission case 7 (rear wheel 3). Protrusively toward.
A brake device 22 is disposed on the outer side of the differential output shaft 20, that is, on the power output side of the differential output shaft 20 (both left and right sides of the differential device 15), and the speed reducer 23 is disposed on the power output side of the brake device 22. The rear axle 16 is connected to the power output side of the reduction gear 23. The brake device 22, the speed reducer 23, and the rear axle 16 are stored in a rear axle case 26 disposed on the left and right sides of the transmission case 7.

A reduction gear 24 of a reduction gear 23 is meshed with the outer end of the differential output shaft 20, and a rotation shaft 24 a of the reduction gear 24 is fixed to a planetary gear 25 of the reduction gear 23, and the planetary gear 25 is located inside the rear axle 16. It meshes with one end. The rear axle 16 is rotatably supported by a bearing 27 provided on the rear axle case 26.
The transmission case 7 has upper and lower walls 30U, 30D and left and right side walls 21L, 21R. The left and right side walls 21L, 21R have openings 18 for projecting the differential output shaft 20 from the inner side to the outer side. Is formed.

The left and right side walls 21L and 21R are formed with annular seats 31 in which the outer diameters (outer in the radial direction) of the left and right side walls 21L and 21R protrude outward in the axial direction (outer in the axial direction of the differential output shaft 20). The thickness D3 of the portion where the seat portion 31 is formed is larger than the normal thickness D4 of the left and right side walls 21L and 21R. The outer peripheral surfaces of the left and right side walls 21L and 21R are formed in two steps by the seat portion 31 and the normal thickness portion 32 which is a normal thickness, and concave cylinder portions 29 (cylinder chambers) are formed in the left and right side walls 21L and 21R. ing.
The cylinder portion 29 can be fitted with a piston 28 having a ring shape and a substantially L-shaped cross section. The piston 28 fitted into the cylinder portion 29 is provided with a hydraulic pressure supply formed on the seat portion 31 of the left side wall 21L. By supplying hydraulic oil to the passage 17, it moves in the same direction as the axial direction of the differential output shaft 20.

Of the left and right side walls 21L, 21R formed on the inner diameter side of the cylinder part 29, a bearing fitting part 33 is formed on the inner diameter side of the right side wall 21R (the inner diameter side of the normal thick part 32). A bearing 39 is fitted to the bearing fitting portion 33.
An attachment portion 36 for attaching the differential support member 35 is formed inside the cylinder portion 29 of the left side wall 21L, and the outer side of the differential support member 35 is bolted to the attachment portion 36.
A bearing 38 that rotatably supports a crank gear 37 (large gear) fixed to the left side (left side wall) of the differential case 34 is fitted on the inner side of the differential support member 35, and the crank gear 37 is attached to the differential case 34. It is connected to the left side.

The right side of the differential case 34 is rotatably supported by a bearing 39 fitted to the bearing fitting portion 33.
Accordingly, the left side of the differential case 34 is supported by the mounting portion 36 via the differential support member 35 and the bearing 38, and the right side of the differential case 34 is supported by the bearing fitting portion 33 via the bearing 37. 7 is freely rotatable.
The differential case 34 is provided with a plurality of pinion shafts 40 (for example, four shafts) that are substantially orthogonal to the differential output shaft 20 and whose axis is arranged at the center in the left-right direction of the mission case 7 (broken line P in FIG. 1). A pinion gear 41 is rotatably supported at the outer end of the pinion shaft 40, and a pair of differential side gears 42 that are engaged with the pinion gear 41 and rotated are provided on the left and right sides of each pinion 41. Each pinion shaft 40, pinion gear 41, and differential side gear 42 are housed in a differential case 34.

As shown in FIG. 1, the pinion shaft 40 and the pinion shaft center of the pinion gear 41 that are substantially orthogonal to the differential output shaft 20 are arranged at the center in the left-right direction of the transmission case 7, and thereby, from the pinion shaft 40. The distance to the left and right brake devices 22 is the same on both the left and right sides.
Each of the differential side gears 42 is spline-fitted to the inner end (base end) side of the pair of differential output shafts 20, and the left differential side gear 42 is rotatably supported by the crank gear 37, and the right differential gear 42 is rotated. The side gear 42 is rotatably supported by the differential case 34.

As shown in FIG. 2, a plurality of engaging recesses 43 provided at equal intervals (for example, 90 ° intervals) in the circumferential direction are formed on the side surface of the right differential side gear 42. The engaging recess 43 is formed integrally when forming the differential side gear 42 when the right differential side gear 42 is forged.
A ring-shaped collar 44 is provided between the inner surface of the differential case 34 and the end surface of the right pinion gear 41 facing the inner surface. A tongue piece 45 that is bent toward the differential case 34 is formed on the outer periphery of the collar 44, and the tongue piece 45 is locked to a locking recess 46 formed on the inner surface of the differential case 34. Since the tongue piece 45 is locked to the locking recess 46, the collar 44 is immovable in the circumferential direction.

Accordingly, when the power from the engine is transmitted to the crank gear 37 of the differential device 15, the differential case 34 is engaged with the pinion gear 41 and the differential side gear 42 when the resistance applied to the left and right rear wheels is substantially the same. If the resistance applied to the left and right rear wheels becomes non-uniform, the mesh between the pinion gear 41 and the differential side gear 42 will be different, and the differential output with the smaller resistance applied to the rear wheels. The rotation speed of the shaft 20 is increased.
In the mission case 7, a diff lock pin 47 for stopping the rotation of the diff device 15 is disposed. That is, a pair of upper and lower differential lock pins 47 are disposed between the right differential case 34 and the bearing fitting portion 33 (bearing 39) formed on the right side wall 21R of the transmission case 7. An insertion hole 48 for inserting the diff lock pin 47 is provided on the side surface of the diff case 34 facing the diff lock pin 47.

Each of the differential lock pins 47 is connected to a shifter 49 for switching the differential lock pin 47 so as to be freely engaged with and disengaged from the engaging recess 43. The shifter 49 is connected to the shifter 49 (the differential lock pin 47) in the axial direction of the differential output shaft 20. A fork 19 for moving in the same direction is provided.
Therefore, the differential lock pin 47 is moved through the shifter 49 so as to approach the differential device 15, and the differential lock pin 47 is engaged with the engagement recess 43 of the pinion gear 41, whereby the differential operation (rotation) of the differential device 15. Can be stopped. That is, the differential lock pin 47 is freely engageable with and disengageable from the differential recess 34 of the differential case 34 and the pinion gear 41, and the differential operation of the differential device 15 is stopped by engaging with the differential recess 34 and the pinion gear 41 to be in an unlocked state. Thus, the operation of the differential device 15 is maintained.

From the middle to the differential output shaft 20, the front end side (outer end side) protrudes outward in the left-right direction from the differential case 34, and a plurality of brake discs 50 of the brake device 22 are provided on the protruding differential output shaft 20 so as to be integrally rotatable. It has been. A plate 51 is provided between the brake discs 50, and a plate 51 is also provided between the innermost brake disc 50 and the piston 28, and these plates 51 are provided in the brake case portion 26 a of the rear axle case 26. The rotation is stopped by a fixing pin 55.
As shown in FIG. 3, a front axle case 62 that supports the front axle 13 is provided at the front portion of the front axle frame 14. A front wheel differential device is provided in the front axle case 62, and a propulsion shaft 63 extending from the transmission case 7 is inserted, and the power transmitted from the propulsion shaft 63 is transmitted through the front wheel differential device to the front axle 14. The front wheel 2 is driven.

The front axle case 62 is provided with front and rear center pins 64F and 64R, and the front and rear center pins 64F and 64R are rotatably supported by front and rear brackets 65F and 65R fixed to the front axle case 62.
As shown in FIG. 4, the front bracket 65F includes a bracket body 67 having an insertion hole 66 into which the front center pin 64F is inserted, and protrudes upward from the bracket body 67 so that the bracket body 67 is attached to the front axle frame 14. A pair of left and right attachment portions 68 to be attached and a pair of left and right contact portions 69 that protrude from the bracket body 67 in the left-right direction and contact the lower portion of the front axle frame 14 are provided. The mounting portion 36, the contact portion 69, and the bracket body 67 are integrally formed of a casting or the like.

Each mounting portion 68 is formed with an insertion hole 73 into which a fastener 70 such as a bolt is inserted. The left-right distance D1 of the mounting portion 68 is substantially the same as the left-right distance D2 of the left-right plate member 60 of the front axle frame 14. Is set.
Further, the respective abutting portions 69 protrude from the lower portion of each mounting portion 68 to the left and right, and the front and rear brackets face the front and rear brackets by the mounting portion 36 protruding upward from the bracket body 67 and the abutting portion 69 protruding left and right. A substantially L-shaped rotation stopper 72 is formed.
Therefore, the mounting portion 68 of the front bracket 65F is fitted between the left and right plate members 60 from the lower side of the front axle frame 14 until the contact portion 69 of the front bracket 65F contacts the lower portion of the left and right plate members 60 of the front axle frame. By aligning the insertion hole 73 of the attachment portion 68 of the front bracket 65F with the insertion holes 74 provided in the side portions of the left and right plate members 60, the fasteners 70 are inserted into the insertion holes 73, 74 and tightened, thereby tightening the front bracket. 65F can be attached to the front axle frame 14.

Thus, when the front bracket 65F is attached to the front axle frame 14, the attachment portion 68 of the front bracket 65F comes into contact with the side surfaces of the left and right plate members 60, and the contact portion 69 of the front bracket 65F comes to the lower portion of the left and right plate members 60. Due to the contact, the front bracket 65F does not rotate in the circumferential direction even if the front center pin 64F rotates due to the influence of the rotation of the front wheel differential device in the front axle case 62.
The rear bracket 65R has the same shape as the front bracket 65F, and includes a bracket body 67 having an insertion hole 66 into which the rear center pin 64R is inserted, a pair of left and right mounting portions 68, and a pair of left and right contact portions 69. The description is omitted.

  As described above, according to the tractor 1, the differential device 15 having the pair of left and right differential output shafts 20 is provided in the mission case 7, and the left and right differential output shafts 20 are respectively connected to the left and right outer sides of the mission case 7. And the center of the pinion shaft 40 of the differential device 15 is arranged at the center in the left-right direction of the transmission case 7 (center line P in FIG. 1), so that the distance between the differential device 15 and the brake device 22 is both left and right. Since the lengths of the left and right differential output shafts 20 from the differential device 15 to the brake device 22 can be made the same, the dual differential output shafts 20 can be shared. Manufacturing cost can be reduced.

Since the cylinder portion 29 of the brake device 22 is formed on the left and right side walls 21L and 21R of the mission case 7, the brake device 22 can be made compact, and the mission case 7 sandwiched between the brake devices 22 can be formed larger.
In addition to the above, a bearing portion 33 (the bearing fitting portion) that supports the differential case 34 of the differential device 15 is formed inward of the cylinder portion 29, and the differential case 34 and the differential case 34 are formed between the bearing portion 33 and the differential case 34. Since the diff lock pin 47 that disengages and engages and stops the rotation of the differential device 15 is disposed, the space in the mission case 7 can be used effectively, and the axis of the pinion shaft 40 of the differential device 15 can be used. The transmission case 7 can be easily arranged at the center in the left-right direction.

  The differential device 15 includes a pinion gear 41 and a differential side gear 42 that is housed in the differential case 34 and rotates in mesh with the pinion gear 41. The differential case 34 is provided with an insertion hole 48 into which the differential lock pin 47 is inserted. 42 is provided with an engaging recess 43 to which the differential lock pin 47 engages. By inserting the differential lock pin 47 into the insertion hole 48 and engaging with the engagement recess 43, the differential side gear 42 is connected to the pinion gear 41. In the engaged state, the differential side gear 42 and the differential case 34 come to rotate integrally, and the differential operation of the differential device 15 can be stopped.

A collar 44 is provided between the inner surface of the differential case 34 and the end surface of the pinion gear 41 facing the inner surface, and a tongue piece 45 that is bent toward the differential case 34 is formed on the outer periphery of the collar 44. Since the locking recess 46 for locking with the tongue piece 45 of the collar 44 is provided on the inner surface, the rotation of the collar 44 can be prevented with a simple configuration.
In addition, since the front and rear brackets 65F and 65R are attached to the front axle frame 14 from the side (side), the attachment of the front and rear brackets 65F and 65R is very simple. By forming the front-rear brackets 65F and 65R with a substantially L-shaped detent 72 in front view, the burden on the fastener 70 such as a bolt can be reduced even if the front and rear center pins 64F and 64R rotate.

It is front sectional drawing of the differential apparatus for rear wheels. It is sectional drawing of a differential side gear. 1 is an overall side view of a tractor according to the present invention. It is a perspective view which attaches a front bracket to a front axle frame.

Explanation of symbols

1 Tractor 7 Mission case 15 Differential device 20 Differential output shaft 22 Brake device 34 Differential case 40 Pinion shaft

Claims (4)

In the tractor provided with a differential device having a pair of left and right differential output shafts in the mission case, and provided with a pair of left and right brake devices to which the left and right differential output shafts are respectively connected to the left and right sides of the mission case,
A tractor characterized in that a pinion shaft center of a pinion gear orthogonal to the differential output shaft is arranged at the center in the left-right direction of the transmission case.   A cylinder part for disposing the piston of the brake device is formed on the left and right side walls of the transmission case, and a bearing part for supporting the differential case of the differential apparatus is formed inward of the cylinder part. The tractor according to claim 1, wherein a differential lock pin for stopping the differential operation of the differential device is arranged between the differential case and the differential case.   The differential device includes a pinion gear supported by the pinion shaft and housed in a differential case, and a differential side gear meshing with the pinion gear, the differential case having an insertion hole into which a differential lock pin is inserted, and the differential side gear The tractor according to claim 2, wherein an engagement recess for engaging the differential lock pin is provided on the tractor.   A collar is provided between the inner surface of the differential case and the end surface of the pinion gear facing the inner surface, a tongue piece that bends toward the differential case is formed on the outer periphery of the collar, and a collar is formed on the inner surface of the differential case. The tractor according to any one of claims 1 to 3, wherein a locking recess for locking the tongue piece is provided.

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