JP3561397B2 - Tractor transmission - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tractor transmission, and more specifically, it is possible to configure a flat deck for an entrance / exit and a control floor including an upper surface of a tractor vehicle body, and to reduce the center of gravity of the tractor vehicle body, particularly when applied to a paddy field tractor. Transmission.
[0002]
[Prior art]
2. Description of the Related Art A tractor transmission in which a PTO transmission having a PTO transmission that drives a PTO shaft and a traveling transmission that drives a rear wheel differential device are respectively linked to an engine is known.
[0003]
[Problems to be solved by the invention]
In a conventional tractor transmission, the output shaft of the engine, the propulsion shaft of the traveling system transmission located on the extension axis, and the drive shaft of the rear wheel differential device are installed substantially apart from each other above and below the tractor body. The position of the center of gravity of the tractor is considerably high, and when a cabin or the like is mounted, the position of the center of gravity increases further, making it unsuitable as a paddy field tractor.
[0004]
In addition, as the center of gravity of the tractor becomes higher, the height of the tractor increases as well as getting on and off, and it is difficult to construct a flat deck on the upper surface of the tractor body and the floor deck provided to cover it, resulting in poor maneuverability. There were challenges. In addition, the tractor is a traveling power vehicle, and the workability of a rotary cultivator and the like is mounted on the rear of the tractor with a link mounting body such as a three-point link so that the workability can be raised and lowered. In such a case, there is a problem that the weight balance between the front and the rear tends to be deteriorated.
[0005]
In view of the above problems, the present invention lowers the tractor center of gravity (lower) by erection of the output shaft of the engine (including on the extended axis) and the drive shaft of the rear wheel differential device vertically close to the tractor body. Position), and the main purpose is to make a floor deck or the like a flat deck, and the secondary purpose is to improve the front-rear weight balance of the tractor. Things.
[0006]
[Means for Solving the Problems]
In a tractor transmission, a PTO transmission having a PTO transmission that drives a PTO shaft and a traveling transmission that drives a rear wheel differential device are respectively linked to an engine and mounted on a tractor body, the above-described main object is achieved. To achieve this, the following technical measures have been taken.
[0007]
In other words, the transmission of the tractor according to the present invention is configured such that the propulsion axis of the traveling transmission located on the output shaft of the engine and the extension axis thereof and the differential drive shaft of the rear wheel differential device are vertically parallel and close to each other. (Claim 1).
By adopting such a configuration, not only can the center of gravity of the tractor be at a low position, but also on a flat deck, and even if a cabin is mounted, running stability and steering stability can be achieved with high output and multi-stage transmission, In particular, it became meaningful when applied to paddy field tractors.
[0008]
The transmission of the tractor according to the present invention, in addition to the configuration of claim 1, further comprises an input shaft of an independent PTO clutch mounted on a propulsion shaft of the traveling system transmission and directly connected to an output shaft of the engine. A PTO transmission driven via a PTO clutch is arranged on the front side of a rear wheel differential device (claim 2).
[0009]
By adopting such a configuration, the front-rear weight balance of the tractor was successfully improved.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a tractor with a cabin employing a transmission according to the present invention. The tractor 1 is a two-axis four-wheel type having left and right front wheels 2 and left and right rear wheels 3. Is constituted by connecting a clutch housing and a transmission case 6 to an engine 5. The engine 5 is covered with a bonnet 7 together with engine accessories such as a radiator.
[0011]
A hydraulic elevating device 9 having a pair of left and right lift arms 8 is mounted on the rear upper surface of the tractor body 4, and a working machine 11 shown as a rotary tiller is raised and lowered on the hydraulic elevating device 9 via a three-point link 10. It is freely attached.
The cabin 12 mainly includes left and right rear wheel fenders 13, a floor seat 14 connecting the fenders 13, and a box-shaped cabin body 15. The upper surface of the vehicle body including the floor seats 14 is a flat deck, It surrounds the steering handle 16 and the driver's seat 17 and has a door 18 which can be opened and closed on the left and right.
[0012]
Referring to FIG. 2, the entire transmission according to the present invention is shown in a partially unfolded state, and the transmission includes a PTO transmission unit (PTO transmission) at an output side of an independent PTO clutch 19 directly connected to the engine 5. The tractor body 4 includes: a PTO transmission including a transmission 20; a traveling transmission including a main transmission 21, a subtransmission 22, a creep transmission 23, and a shuttle transmission 24 and driving a rear wheel differential device 25. A gear reduction device 26 is provided at the rear end of the tractor body 4 and is transmitted to a PTO shaft 27.
[0013]
More specifically, with reference to FIG. 2, a traveling system input shaft (traveling system propulsion shaft) 30 is connected to an engine crankshaft (output shaft) 28 via a traveling system main clutch 29 so as to be intermittent. The input shaft 30 has a cylindrical shaft structure, and a PTO type propulsion shaft (input shaft) 31 is inserted into the input shaft 30 and is directly connected to the engine crankshaft 28.
[0014]
The main transmission 21 is provided so as to be parallel to the upper or upper part of the input shaft 30, and to a transmission gear group 32 of first to fourth speeds fixed or fixed to the input shaft 30 at an axial interval. A counter shaft 33 is provided with a first-fourth-speed transmission gear group 34 meshing with the transmission gear group 32 and a transmission shifter 35, and as shown in FIG. By the axial sliding switching of the shifter 35, a synchromesh type constant mesh speed change from 1F (1st speed) to 4F (4th speed) is performed.
[0015]
An input shaft 36 of the shuttle transmission 24 is connected to an output side (counter shaft 33) of the main transmission 21 via a hydraulic clutch (also serving as a brake for inertia) 37, and both shafts 33 and 37 are the same shaft. It is located on the heart.
A transmission gear 38 for forward rotation and a transmission gear 39 for reverse rotation are provided on the input shaft 36 at an axial interval so as to freely rotate, and a shifter 40 for turning on and off these gears 38 and 39 is slidable. The shifter 40 is a synchromesh (synchronous occlusion type).
[0016]
A transmission shaft 41 of the auxiliary transmission 22 having a cylindrical structure is provided below the input shaft 36, and the transmission shaft 41 is provided with an interlocking gear 42 meshing with the forward rotation transmission gear 38 and this gear 42. A transmission gear 43 for high-speed sub-transmission and a transmission gear 45 for low-speed sub-transmission meshing with the transmission gear 39 for reverse rotation via a shuttle gear 44 are fixedly provided.
[0017]
The propulsion shaft 31 of the PTO system is inserted into the transmission shaft 41 of the auxiliary transmission 22, so that the input shaft 30 of the main transmission 21 and the transmission shaft 41 of the auxiliary transmission 22 have substantially the same axis. It is erected on the front and back.
The counter shaft 46 of the auxiliary transmission 22 is installed in parallel below the transmission shaft 41, and the counter shaft 46 has a substantially cylindrical structure, and covers the drive system shaft 47 of the rear wheel differential device 25. Have been.
[0018]
The counter shaft 46 is provided with a sub-transmission high-speed gear 48 meshing with the transmission gear 43 and a sub-transmission low-speed gear 49 meshing with the transmission gear 45 so as to freely rotate (relatively rotate). The high and low speed gears 48 and 49 can be turned on and off by a shifter 50 slidable in the axial direction.
That is, in FIGS. 3 and 5, when the shifter 40 of the shuttle transmission 24 is slid in the direction of arrow F and synchronously engaged with the gear 38, the gear rotates forward, and slides in the direction of arrow R to synchronize with the gear 39. When they are engaged, the rotation is reversed, and when the shifter 50 of the subtransmission 22 is slid in the direction of arrow H to engage in synchronism with the gear 48, the speed is increased, and the shifter 50 is slid in the direction of arrow L to engage with the gear 49. When the synchronous meshing is performed, the speed becomes low. Here, the shuttle gear 44 of the shuttle transmission 24 and the low speed gear 49 of the subtransmission 22 are meshed with the common transmission gear 45.
[0019]
Referring to FIGS. 2 to 5, there is shown a first embodiment in which a creep transmission 23 is disposed at a lower front stage (lower order) of the auxiliary transmission 22, and a creep is provided at a front end of a counter shaft 46 in the auxiliary transmission 22. A drive gear 51 is engraved, and a final creep gear (referred to as a transmission end in creep) 52 is rotatably (idle free) on a differential drive system shaft 47 via a needle, a bush, etc., in front of the gear 51. A shifter 53 is provided on the differential drive system shaft 47 to switch the two gears 51 and 52 on and off with respect to the differential drive system shaft 47.
[0020]
Below the differential drive system shaft 47, a first creep shaft 54 and a second creep shaft 55 are provided in parallel with the shaft, and an interlocking gear 56 that meshes with the drive gear 51 is splined on the first creep shaft 54. An interlocking gear 57 that meshes with the gear 52 is fitted over the gear 57 so as to be relatively rotatable (idle freely) via a needle or a bush. A shifter gear 58 for turning on and off 57 is fitted with a spline or the like, and a creep transmission gear 59 is formed at the front end of the first creep shaft 54.
[0021]
The second creep shaft 55 is fixedly provided with a creep transmission gear 61 for engaging and disengaging a creep gear 60 meshing with the gear 59 and a shifter gear 58.
Therefore, according to the first embodiment, when the shifter 53 slides in the direction of the arrow A and engages with the differential drive shaft 47 via the gear 51 on the counter shaft 46, the shifter 53 does not pass through the creep transmission 23. Thus, the rear wheel differential device 25 can be driven through the auxiliary transmission device 22 and the differential drive system shaft 47, while the shifter 53 is slid in the direction of arrow B to drive the gear 52 and the differential drive. By joining the system shaft 47, a first-stage creep shift and a second-stage creep shift can be performed.
[0022]
In the first-stage creep speed change, the shift gear 58 slides in the direction of arrow C and is joined to the interlocking gear 56, so that the differential drive system via the gear 51 → the gear 56 → the shift gear 58 → the gear 57 → the gear 52 The gear is transmitted to the shaft 47. On the other hand, in the second-stage creep speed change, the shift gear 58 is engaged with the gear 61 as shown in the figure, so that the gear 51 → the gear 56 → the first creep shaft 54 → the gear 59 → the gear 60 → The transmission of the differential drive shaft 47 via the shifter 53 via the gear 61 → the shift gear 58 → 59 → the gear 52 is performed.
[0023]
FIG. 6 shows a second embodiment of the creep transmission 23. The first creep shaft 54 is provided with an interlocking gear 56 meshing with the gear 51 so as to freely rotate with a needle or the like, and is parallel to the gear 56. A small diameter transmission gear 59 is provided.
A creep gear 60 that meshes with the gear 59 and a gear 61 that engages and disengages the shift gear 58 are fixed to the second creep shaft 55 by splines or the like.
[0024]
According to the second embodiment, when the shifter 53 is indicated by an arrow A, the differential drive system shaft 47 is transmitted without passing through the creep transmission 23 as in the first embodiment. When 58 is indicated by an arrow C, the first stage creep shift is performed on the same route as the first embodiment, and when the shift gear 58 is in the state shown in the figure, the second stage creep shift is performed on the same route as the first embodiment.
[0025]
In any of the configurations of the first and second embodiments described above, the counter shaft 46 of the auxiliary transmission 22 is provided over the drive shaft system (drive system shaft) 47 of the rear wheel differential device 25, and the output of the creep transmission 23 is provided. This is input to the auxiliary transmission device 22 on the front side, bypassing the drive shaft system 47.
Referring to FIGS. 2 and 4, a front wheel drive gear 62 is fixed to the differential drive system shaft 47 below the main transmission 21, and a clutch shaft 64 having a hydraulic clutch device 63 via the gear 62. And a front wheel drive shaft 65. The hydraulic clutch device 63 has two hydraulic pistons 67 in a back-to-back relationship with the clutch body 66. DT gear group 69 for driving the front wheels 2 in synchronization with the driving wheel 2 and a double-speed gear group 70 for driving the front wheels 2 with respect to the rear wheels 3 can be switched.
[0026]
Referring to FIG. 2, the differential drive system shaft 47 is joined to a differential drive shaft 72 via a coupling 71. The differential drive shaft 72 has a bevel pinion 73 and has a crown gear 74 of the rear wheel differential device 25. The bevel pinion 73 and the like are quenched (heat treated) to reduce the diameter of the pinion 73 and contribute to weight reduction, and the differential drive shaft 72 is connected to the output shaft 28 of the engine. In addition, it is installed in parallel with the propulsion shaft 30 of the traveling transmission located on the extension axis and is vertically close to each other, whereby it is possible to lower the vehicle center of gravity (lower position). , Including the floor sheet 14 of the cabin 12 and the like.
[0027]
Referring to FIG. 2 and FIG. 7, the independent PTO clutch 19 is of a hydraulic type. When the hydraulic pressure is supplied to press the clutch plate 74 in pressure contact, the independent PTO clutch 19 is brought into contact. A brake means 76 is provided on the output side of the switch 19 so as to prevent inertial idling by operating a brake in conjunction with the movement of the hydraulic piston when the operation of switching from clutch engagement (engagement) to clutch disengagement (off) is performed. I have.
[0028]
The independent PTO clutch 19 is directly connected to the engine, that is, the crankshaft 28 via the propulsion shaft 31, and a clutch output shaft 77 is provided on the same axis as the propulsion shaft 31, and an end portion of the clutch output shaft 77 ( An input gear 78 of the PTO transmission unit (PTO transmission) 20 is formed on the rear end), and the input gear 78 is formed with an engaging portion 78A.
[0029]
As shown in FIGS. 7 and 8, the PTO transmission device 20 includes a shift gear 80 having large and small gears 80 </ b> A and 80 </ b> B mounted on a PTO transmission shaft 79 laid on the same axis as the clutch output shaft 77 via internal and external splines. As shown by an arrow X in the axial direction, a PTO speed change counter shaft 81 is laid slidably under the PTO speed change shaft 79 in parallel with the PTO speed change shaft 79. In the figure, the counter shaft 81 is fitted on the differential drive shaft 72 so as to be relatively rotatable (slidable).
[0030]
The counter shaft 81 has a transmission gear 82 meshing with the input gear 78, a transmission gear 83 for PTO second speed (2P), a transmission gear 84 for PTO first speed (1P), and a gear 85 for PTO reverse rotation (PR). Are provided with an axial interval from the front to the rear in the order described above, and an idle gear 86 meshing with the gear 85 is provided on the back shaft 87.
[0031]
That is, as is apparent with reference to FIG. 2, the PTO transmission unit 20 is disposed on the front side of the rear wheel differential device 25, and the shuttle transmission unit 24 is disposed on the upper front side of the PTO transmission unit 20. By arranging the auxiliary transmission device 22 and the creep transmission device 23 below the shuttle transmission device 24, the position of the center of gravity of the vehicle is shifted toward the front side, and in the illustrated embodiment, the front wheel drive effect is provided below the main transmission device 21. By disposing the hydraulic clutch device 63, etc., the vehicle weight center position is relatively closer to the front side, and the front-rear weight balance in the work in which the work machine 11 shown in FIG. 1 is mounted is improved.
[0032]
Referring to FIG. 7 and FIG. 8, the gear shifting mode of the PTO transmission 20 will be outlined. When the large gear 80A of the shift gear 80 is linked to the gear 85 via the idle gear 86 (see PR in FIG. 8), the input gear 78 → Since the shift gear 80 is spline-coupled to the transmission shaft 79 via the gear 82 → gear 85 → gear 86 → gear A, the transmission shaft 79 rotates in the reverse direction of the PTO. The PTO shaft 27 is reversely driven via the PTO reduction device 26 via the shaft 89. This reverse drive is used, for example, when the work implement 11 is a rotary tilling machine to cut up a claw shaft (tiling shaft). It is used.
[0033]
Next, when the lower gear 80A is brought into mesh with the gear 84 by sliding the shift gear 80 (see 1P in FIG. 8), the PTO transmission via the input gear 78 → the gear 82 → the gear 84 → the lower gear 80A is positive. The first speed (1P) is established, and the speed change shaft 79 is driven.
Further, when the shift gear 80 is slid to a position where the large and small gears 80A, 80B are not engaged with any of the gears 83, 84 (see NP in FIG. 8), the PTO transmission 20 is in a neutral state, and the shift gear 80 is slid. Then, when the small gear 80B is engaged with the gear 83 (see 2P in FIG. 8), the speed change shaft 79 becomes the second forward speed (2P) via the gear 78 → the gear 82 → the gear 83 → 80B, and further, By sliding the shift gear 80 and engaging its internal spline with the engagement portion 78A to directly connect the output shaft 77 and the transmission shaft 79 (see 3P in FIG. 8), the third forward speed (3P) It becomes.
[0034]
As is clear from the above description, the PTO shift pattern becomes a so-called I-shaped pattern in the order of 3P, 2P, NP, 1P, and PR from the front to the rear, so that operability is improved and only one shift fork is required. Not only can it be down, but also assembly and disassembly and maintenance become easier.
Further, in the illustrated embodiment, the inner spline of the shift gear 80 is formed in the front and rear direction in the axial direction, and a middle portion in the axial direction is a hollow portion 80C, while the outer spline of the transmission shaft 79 is formed in the front and rear direction in the axial direction. The intermediate portion in the axial direction is formed as a hollow portion 79A. With this configuration, one of the inner and outer splines at 1P and 2P (in 1P, the rear inner spline of the shift gear 80 and the rear of the transmission shaft 79). In the case of 2P, the front spline of the shift gear 80 and the front outer spline of the transmission shaft 79 are engaged, and the shift gear 80 is prevented from shifting out (sliding in the axial direction from the shift positions 1P, 2P). -ing
[0035]
In the embodiment described above, the left and right yoke shafts (output shafts) of the rear wheel differential device 25 are linked to the rear wheel 3 via the final reduction gear, and the rear wheel transmission system includes a brake device. Is done. The front wheel drive shaft 65 is input to the front wheel differential device.
[0036]
【The invention's effect】
As described above in detail, according to the present invention, the position of the center of gravity of the tractor vehicle body can be lowered, and the upper surface of the vehicle body including the entrance / exit and the floor seat can be made a flat deck.
[Brief description of the drawings]
FIG. 1 is a side view of a tractor employing a transmission according to the present invention.
FIG. 2 is a side view showing a partially developed entire transmission according to the present invention.
FIG. 3 is a side view showing a main transmission and a shuttle transmission in the traveling transmission.
FIG. 4 is a side view showing a main transmission, a creep transmission, and a front wheel drive device of the traveling transmission.
FIG. 5 is a side view of the first embodiment showing a shuttle transmission, an auxiliary transmission, and a creep transmission among the traveling system transmissions.
FIG. 6 is a side view of a second embodiment showing a subtransmission and a creep transmission among the transmissions of the traveling system.
FIG. 7 is a side view showing a PTO transmission and a rear wheel differential device.
FIG. 8 is a sectional view of a PTO transmission.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tractor 4 Tractor body 5 Engine 19 Independent PTO clutch 20 PTO transmission 21 Main transmission 22 Sub transmission 23 Creep transmission 24 Shuttle transmission 25 Rear wheel differential device 30 Propulsion shaft 72 Differential drive shaft

Claims (2)

A propulsion shaft of a PTO system directly connected to the engine is inserted into a traveling system input shaft having a cylindrical shaft structure to which power from the engine is transmitted, and power is supplied to a rear wheel differential device below the PTO propulsion shaft. A differential drive shaft for transmitting is provided in parallel, and an input shaft to which power from the traveling system input shaft is transmitted via the main transmission is provided substantially parallel to the PTO propulsion shaft behind the main transmission. A subtransmission having a shuttle device disposed therein, and a cylindrical transmission shaft to which power is inputted from an input shaft of the shuttle device via the shuttle device as an external fitting to the PTO-system propulsion shaft below the shuttle device. The auxiliary transmission is provided with a counter shaft for outputting power from the auxiliary transmission as an external fitting to a differential drive system shaft, and an output from the counter shaft is output from the counter shaft to the front side of the auxiliary transmission. Can be transmitted to the system axis A leap transmission is arranged, and the transmission shaft of the subtransmission is meshed with a shuttle gear meshing with a reverse rotation transmission gear provided on the input shaft of the shuttle device and a low speed gear provided on a counter shaft of the subtransmission. A transmission for a tractor, comprising: a transmission gear ; A front wheel drive gear is fixed to the differential drive system shaft below the main transmission, and power is supplied from the front wheel drive gear to the front side of the creep transmission so as to drive the front wheels in synchronization with the rear wheels. The tractor according to claim 1, further comprising a hydraulic clutch device that switches between a transmission state and a state in which power is transmitted from a front wheel drive gear so as to drive the front wheel relative to the rear wheel. transmission.

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