JP3616557B2 - Tractor mission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tractor mission.
[0002]
[Prior art]
When performing front data work, earth removal work, etc. on a tractor, shuttle speed change is made to the driving transmission system linked to the engine in order to switch back and forth frequently and to make the forward and backward vehicle speed the same speed or substantially the same speed. The mission of a tractor provided with an apparatus and a main transmission is known, for example, in Japanese Patent Laid-Open No. 10-6790.
[0003]
[Problems to be solved by the invention]
A conventional shuttle transmission in a tractor transmission is a gear shift switching by a gear train, and even if it is a synchronous bite type gear shift switching, since it is mechanical, there is a gear shift shock, and the bite portion is easily damaged. there were.
In order to prevent damage to the occlusal portion when performing shift switching (forward / reverse switching), it is necessary to synchronize, and this synchronization time (time lag) becomes an obstacle to rapid shift switching. It was a cause of delay in loader work.
[0004]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems by adopting a hydraulic transmission switching system for the shuttle transmission.
[0005]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention takes the following technical means.
That is, the tractor mission according to claim 1 is provided with a main transmission shaft 4 behind the axial extension of the propulsion shaft 3 interlocked with the engine 1 and a transmission subshaft 5 in parallel with the main transmission shaft 4, A main transmission unit 7 is constituted by a gear train 6 provided on the main transmission shaft 4 and the transmission auxiliary shaft 5, and a hydraulic shuttle transmission 10 is provided on the propulsion shaft 3. Forward rotation is transmitted to the main transmission shaft 4 via the main transmission portion 7, while reverse rotation is transmitted to the transmission auxiliary shaft 5 via the back gear train 11 and via the main transmission portion 7. It is characterized by.
[0006]
By adopting such a configuration, when the forward / reverse movement is frequently switched during loader work or the like, the forward rotation 10B and the reverse rotation 10A of the hydraulic shuttle device 10 can be quickly switched by the control valve 19 without a time lag. The shift (switching) shock can be absorbed by the oil.
It is recommended that the propulsion shaft 3, the back gear train 11 and the hydraulic shuttle transmission 10 are supported by an inner casing 20 built in a transmission case 19 constituting a tractor vehicle body (Claim 2).
[0007]
As a result, it can be compactly accommodated in the mission case 19, and a kit (assembly) can be formed in the inner casing 20, so that assembly and disassembly and maintenance are convenient.
In the above-described claim 1 or 2, the propulsion shaft 3 is interlocked with the engine 1 via the damper means 2, and the sub-transmission portion 22 and / or the gear train is provided on the exit side of the main transformation portion 7. It is recommended that the creep transmission 23 by the train is provided to transmit to the rear wheel differential device 24 (claim 3).
[0008]
By adopting such a configuration, it is possible to achieve ultra-low speed when performing deep plowing / crushing soil plowing work and trencher work with a rotary, and the significance as a traveling power vehicle as a tractor is doubled.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a main transmission unit using a hydraulic shuttle transmission and a gear train, and FIG. 2 shows a configuration in which a sub-transmission unit using a gear train and / or a creep transmission unit using a gear train is provided on the exit side of the main transmission unit. FIG. 3 schematically shows the entire traveling transmission system and the PTO transmission system described above.
1 to 3, a propulsion shaft 3 is interlocked and connected to an engine (engine flywheel in the figure) 1 via a damper means 2.
[0010]
In addition, since the damper means 2 relieves (absorbs) the rotational force of the engine or the load on the engine, it is provided with the axial length of the coil spring 2A shown in FIG. 3 as the circumferential arrangement.
A main transmission shaft 4 is installed on the rear side of the axial extension of the propulsion shaft 3, and the main transmission shaft 4 is a cylindrical shaft.
A transmission subshaft 5 is installed in parallel with the main transmission shaft 4. In this example, the transmission subshaft 5 is installed above the main transmission shaft 4, and the main transmission section is provided by a gear train 6 provided between the shafts 4 and 5. In the figure, the main transmission unit 7 is a four-speed transmission (first speed to fourth speed) that shifts in synchronization with the sliding of the first shifter 8 and the second shifter 9 in the axial direction back and forth in a synchronous occlusion type. It is said that.
[0011]
A hydraulic shuttle transmission (hydraulic pack) 10 is provided on the propulsion shaft 3, and the transmission 10 includes a reverse rotation 10A and a forward rotation 10B arranged side by side in the axial direction. The reverse transmission 10 </ b> A is transmitted to the main shaft 4 through the main transmission unit 7, and the reverse rotation 10 </ b> A is transmitted to the transmission subshaft 5 through the back gear train 11 and through the main transmission unit 7.
Referring to FIG. 1, a hydraulic shuttle transmission 10 has pistons 14 </ b> A and 14 </ b> B slidably fitted to front and rear cylinder portions of a clutch body 13 that is coupled to a propulsion shaft 3 via a key 12. The clutch plates 16A and 16B arranged in the front-rear direction on the hook-shaped clutch mounting plates 15A and 15B can be pressed against the pressure receiving plates 18A and 18B and the pistons 14A and 14B against the return springs 17A and 17B. The pressure oil from the pump (not shown) passes through the passages 21A and 21B formed in the radial direction from the passages 20A and 20B formed as the axial direction in the propulsion shaft 3 through the switching operation (on / off operation) of the control valve 19. Liquid can be fed to the front and rear cylinders.
[0012]
The cylindrical boss of the clutch mounting plate 15A for reverse rotation 10A is fitted on the propulsion shaft 3 so as to be rotatable (freely rotatable), and a reverse drive gear 11A is formed on the cylindrical boss. 11B is linked to the reverse driven gear 11C on the transmission countershaft 5 and constitutes a back gear train 11 and is disposed on the front side of the hydraulic shuttle transmission 10.
The cylinder boss of the clutch mounting plate 15B of the forward rotation 10B is rotatably supported via a ball bearing and a sleeve bearing, respectively, across the propulsion shaft 3 and the front portion of the main transmission shaft 4, and a drive gear is provided on the outer periphery of the boss. 6A is engraved, and the transmission gear 6B on the transmission countershaft 5 is engaged with the drive gear 6A.
[0013]
The propulsion shaft 3, the back gear train 6 and the hydraulic shuttle transmission 10 are supported by front and rear bearings 21A, 21B, etc. via an internal casing 20 built in a housing 19A of a transmission case 19 constituting a tractor vehicle body.
The inner casing 20 is a combination of first and second bowl-shaped casings 20A and 20B and is assembled with bolts or the like not shown, and the second casing 20B is attached to the partition wall 19B of the housing 19A with bolts or the like not shown. (See FIG. 2).
As shown in FIG. 2, the main transmission unit 7 capable of shifting in four steps by the gear train 6 is relatively front and rear relative to the transmission gear 6B and the driving gear 6A fixed to the transmission subshaft 5 meshing with the driving gear 6A. A transmission gear 6C that is freely rotatable on the main transmission shaft 4, a transmission gear 6D that is fixed to the transmission subshaft 5 that meshes with the gear 6C, and a row fixed on the main transmission shaft 4 behind the transmission gear 6C. The transmission gears 6G and 6H are supported on the transmission countershaft 5 that meshes with the transmission gears 6E and 6F, respectively. The gear trains 6A and 6B are used for the first transmission, the gear train 6C, 6D is the second shift, and the first and second shifts including the neutral can be switched by sliding back and forth in the axial direction of the first shifter 8 of the synchronous occlusion type, and the gear trains 6E and 6G can switch the first shift. 3 shift, 4th shift with gear trains 6F, 6H Switching of the third-4 shift is possible, including the neutral axial longitudinal sliding of 9.
[0014]
On the exit side of the main transmission unit 7, a traveling transmission system is provided that includes a sub-transmission unit 22 of high and low gears by a gear train and / or a creep transmission unit 23 by a gear train and that is transmitted to a rear wheel differential device 24. The wheel can be driven via a final reduction gear (not shown).
As shown in FIG. 2, the sub-transmission unit 22 based on the gear train includes two (high and low) gears 22 </ b> A and 22 </ b> B fixed on the main transmission shaft 4 at an axial interval, Two (high and low) gears 22C and 22D, which are engaged with the gears 22A and 22B and are engaged with the gears 22A and 22B, respectively, are freely fitted on the transmission countershaft 25 installed in the transmission case 19 in parallel. , 22D, and a third shifter 22E that can be freely engaged and disengaged. A pinion type in which the height is selected by sliding in the axial direction of the third shifter 22E and is joined to the transmission subshaft 25 by a coupling 26. The differential drive shaft 27 is transmitted.
[0015]
The creep transmission unit 23 has a large gear 23B and a small gear 23C fixed to a creep shaft 23A installed in the transmission case 19 so as to be parallel to the transmission subshaft 25. The large gear 23B is a small gear formed on the gear 22D. The small gear for creep 23C is engaged with a large gear 23E provided on the transmission countershaft 25 so as to freely rotate, and the large gear 23E is engaged with and disengaged by the fourth shifter 23F to be switched to an ultra-low speed. It is supposed to be free.
Note that the transmission subshaft 25 also serves as a front wheel drive system, and forms a front wheel drive gear train 27 across the front wheel propulsion shaft 26 and the subshaft 25. In the figure, rear wheel drive is performed by switching operation of the fifth shifter 28. The front wheel propulsion shaft 26 is linked to a front wheel differential device (not shown) and can drive the left and right front wheels.
[0016]
Referring to FIG. 1, a PTO drive shaft 29 is joined (directly connected) to the rear end of the propulsion shaft 3 by spline coupling or the like, and this PTO drive shaft 29 is slightly in the main transmission shaft 4 which is a cylindrical traveling system. As shown in FIG. 2, a hydraulic PTO is inserted through an elastic coupling 31 that is extended rearward beyond the rear end of the main transmission shaft 4 and embedded with rubber or the like. The clutch (hydraulic pack) 32 is interlocked and connected.
The PTO clutch 32 is linked to a PTO transmission 34 by a gear via a transmission shaft 33 and can drive the PTO shaft 35 (see FIG. 3).
[0017]
As shown in FIG. 4, the PTO clutch 32 is fitted into the cylinder chamber of the clutch body 32A, which is fitted on the transmission shaft 33 and connected by a spline or the like, so that the piston 32B is slidable by hydraulic pressure against the return spring 32C. The multi-plate clutch plate 32D interposed between the boss 31A of the coupling 31 can be pressed (the piston shown in the upper part of FIG. 4 is in a pressure contact state, and the piston shown in the lower part is in a non-pressure contact state). When the pressure is applied, the inertia stop plate (continuous rotation prevention plate) 32G is moved against the spring 32H via the interlocking pin 32F, and when the hydraulic pressure is released, the prevention plate 32G is pushed against the fixed plate 32I by the elastic restoring force of the spring 32H. By attaching it, it prevents the continuous rotation.
[0018]
This hydraulic PTO clutch 32 can be supplied with pressure oil from a PTO valve 36 for turning on and off the PTO transmission system shown in FIGS. 2 and 3 through a supply passage 36A. Oil is blown out for lubrication or cooling to lubrication parts such as bearings, sliding portions, and clutch plates.
For this reason, the return oil is received from the lubricating oil receiving port 37 shown in FIG. 4 and introduced into the passage 38 formed in the axial direction of the transmission shaft 33 to cool the clutch plate 32D through the radial communication hole 39. While being discharged, it flows out forward through a passage 40 formed in the PTO drive shaft 29 as an axial direction.
[0019]
The passage 40 communicates with an oil reservoir 41 formed between the rear end of the propulsion shaft 3 as shown in FIG. 1, and the oil in the oil reservoir 41 is formed as a radial direction in the propulsion shaft 3 and a clutch. The clutch plate 16B of the forward rotation 10B is cooled with the centrifugal force etc. as the lubrication of the bearing and the like through the communication passage formed in the body and is formed in the propulsion shaft 3 through the oil reservoir 41. Then, the clutch plate 16A for reverse rotation is cooled through the axial passage 44 and the radial passage 45, etc., and is first blown with centrifugal force and the like for lubrication of the bearing and the like.
[0020]
Further, the passage 40 formed in the shaft center of the PTO drive shaft 29 communicates with the slight clearance 30 through a radial through hole 46 formed in the vicinity of the front end thereof and has a plurality of diameters formed in the main transmission shaft 4. The lubricating oil can be blown out by centrifugal force or the like to the gear meshing portion, the bearing and the like of the main transmission portion 7 through the through-holes 47 in the direction and the plurality of through-holes 48 formed in the sleeve bearing. By supplying to the spline joint between the PTO drive shaft 29 and the PTO drive shaft 29, fretting (rusting) of the joint is reliably prevented.
The passages 20A and 20B for the forward and reverse rotations 10A and 10B are closed by screw plugs 49, and a lubricating passage 44 is provided on the propulsion shaft 3 as an axial direction adjacent to the passages 20A and 20B. It is formed with a bottom.
[0021]
In the embodiment of the present invention, the passage 40 formed as an axial direction in the PTO drive shaft 29 may be two or more, and return oil for PTO and surplus oil are circulated to the mission case 19 after being lubricated and cooled. Each gear is oil bathed in this bath.
[0022]
【The invention's effect】
As described above in detail, according to the present invention, the forward / reverse switching operation can be performed quickly and without increasing shock, and a tractor mission suitable for loader work or the like can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a hydraulic shuttle transmission and a main transmission that are main parts in an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a main part of a tractor mission.
FIG. 3 is an overall configuration diagram of a tractor mission.
FIG. 4 is a cross-sectional view of a PTO hydraulic clutch device.
[Explanation of symbols]
1 Engine 2 Damper means 3 Propulsion shaft 4 Main transmission shaft (transmission main shaft)
5 Transmission Subshaft 6 Gear Train 7 Main Transmission 10 Hydraulic Shuttle Transmission 10A Reverse 10B Forward

Claims (3)

A main transmission shaft (4) is provided on the rear side of the axial extension of the propulsion shaft (3) linked to the engine (1), and a transmission subshaft (5) is provided in parallel with the main transmission shaft (4). A gear train (6) provided on the transmission shaft (4) and the transmission auxiliary shaft (5) constitutes a main transmission section (7), and a hydraulic shuttle transmission (10) is provided on the propulsion shaft (3). The hydraulic shuttle transmission (10) is provided with a reverse rotation (10A) and a forward rotation (10B) arranged in parallel in the axial direction, and the forward rotation of the hydraulic shuttle transmission (10) is controlled by the main transmission shaft. (4) by transmission through the main transmission unit (7), whereas, via the main transmission section and the transmission (7) to the shift countershaft reversal through the reverse gear train (11) (5) and it is,
The forward rotation (10B) of the hydraulic shuttle transmission (10) is disposed closer to the main transmission (7) side than the reverse rotation (10A), and the cylinder of the clutch mounting plate (15B) for forward rotation (10B). The boss is rotatably supported across the propulsion shaft (3) and the front portion of the main transmission shaft (4), and a drive gear (6A) is formed on the outer periphery of the cylindrical boss. (6A) is engaged with the transmission gear (6B) on the transmission countershaft (5),
The main transmission unit (7) directly connects the cylindrical boss to the main transmission shaft (4) to form one shift stage, and the transmission gear (6A) and the transmission gear (6B) to the transmission countershaft (5) The tractor mission is characterized in that another speed is formed by transmitting power to the main transmission shaft (4) via the gear train (6) . The propulsion shaft (3), the back gear train (11), and the hydraulic shuttle transmission (10) are supported by an inner casing (20) built in a transmission case (19) constituting a tractor vehicle body, and the cylindrical boss Extends through the inner casing (20) toward the main transmission (7) outside the inner casing (20), and the drive gear (6A) is connected to the main transmission of the cylindrical boss. The tractor mission according to claim 1, wherein the tractor mission is formed on an outer periphery of the tractor. The outlet side of the main speed change unit (7), said main transmission shaft (4) auxiliary transmission unit according to the gear train provided on the parallel shift auxiliary shaft (25) and (22) and creep gear unit (23) The sub-transmission unit (22) has a front high gear (22C) and a rear low gear (22D) that are selectively engaged with the transmission sub-shaft (25). The portion (23) includes a small gear (23D) that rotates integrally with the low gear (22D), and a reduction gear transmitted from the small gear (23D) to the front side of the high gear (22C). 25. A tractor mission according to claim 1 or 2, characterized in that it has a large gear (23B) engaged and disengaged to 25) .

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