JP4095740B2 - A continuously variable transmission mechanism for agricultural tractors. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique using an infinite transmission mechanism unit configured by a variable displacement pump, a variable displacement motor, and a fixed displacement motor as a continuously variable transmission mechanism of an agricultural tractor.
[0002]
[Prior art]
Conventionally, many techniques using an HST transmission configured by a variable displacement pump and a variable displacement motor as a continuously variable transmission mechanism of an agricultural tractor have been known.
[0003]
[Problems to be solved by the invention]
In the present invention, an infinite transmission mechanism unit having a variable displacement motor is arranged and arranged in the closed circuit of the HST transmission instead of the conventional HST transmission. . The infinite transmission mechanism unit that combines the variable displacement pump, the variable displacement motor, and the fixed displacement motor allows the main transmission mechanism and the auxiliary transmission mechanism to be performed by the infinite transmission mechanism unit. The main transmission mechanism can be operated with the main transmission mechanism and the auxiliary transmission lever without connecting / disconnecting the main clutch mechanism. Further, with this configuration, the transmission case is configured so that there is no need to dispose a conventional gear sliding type or synchromesh type transmission mechanism.
[0004]
[Means for Solving the Problems]
The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.
[0005]
In claim 1, an infinite transmission mechanism unit (U) is interposed in a transmission for an agricultural tractor, and the infinite transmission mechanism unit (U) includes a variable displacement pump (P), a variable displacement motor (M1), and a fixed displacement. The motor (M2) and the oil passage plate (7) are configured to transmit the power from the engine (E) to the variable displacement pump (P), and the movable swash plate of the variable displacement pump (P) is connected to the main speed change operation mechanism (9 ) To supply the variable pressure oil to the variable displacement motor (M1) and the fixed displacement motor (M2), and the main transmission operation mechanism (9) of the movable swash plate of the variable displacement pump (P). By the operation, the main transmission of the continuously variable transmission output shaft (2) is performed, and the pressure oil discharged from the variable displacement pump (P) is connected to the variable displacement motor (M1) and the fixed displacement via the oil passage plate (7). Supply to motor (M2), variable capacity motor (M1) The movable swash plate is operated by the auxiliary transmission lever (8) to perform the auxiliary transmission of the continuously variable transmission output shaft (2), and the movable swash plate of the variable displacement pump (P) is operated by the main transmission operating mechanism (9). The main transmission mechanism performs a shift in which the forward and reverse rotations are performed along the linear curve (30), and the movable swash plate of the variable displacement motor (M1) by the auxiliary transmission lever (8) is provided. The auxiliary shift operation is performed by changing the angle of the linear curve (30) by the linear curve (31, 32), and without turning off the power from the engine (E). The main transmission operating mechanism (9) or the auxiliary transmission lever (8) can be continuously or separately operated .
[0006]
According to a second aspect of the present invention, in the continuously variable transmission mechanism of the agricultural tractor according to the first aspect, a clutch housing in which an infinite transmission mechanism unit (U) is interposed between the engine (E) and the transmission case (MC). H) Interior .
[0007]
In claim 3, in the continuously variable transmission mechanism of the agricultural tractor according to claim 1, the infinite transmission mechanism unit (U) is attached to the front part of the transmission case (MC) in which the differential gear mechanism (D) is installed, The engine (E) and the transmission case (MC) are connected by a body frame (10) .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described.
[0009]
FIG. 1 is a side sectional view showing the configuration of a continuously variable transmission mechanism of an agricultural tractor according to the present invention. FIG. 2 is an infinite transmission mechanism unit U attached to the front of a mission case MC to shorten the length of the continuously variable transmission mechanism. FIG. 3 is a side cross-sectional view showing an arrangement, and FIG. 3 is a side cross-sectional view of an embodiment in which an infinite transmission mechanism unit U is attached to the front end of the transmission case MC and a large connecting clutch housing is eliminated and the airframe is configured by the airframe frame 10. 4 is a plan view showing the clutch housing H and the transmission case MC of the embodiment of FIG. 2, FIG. 5 is a front view of the infinite transmission mechanism unit U, and FIG. 6 is a diagram showing the main transmission operating mechanism 9, the auxiliary transmission lever 8, and the seat 12. FIG. 7 is a plan view showing the arrangement of the steering handle 11, FIG. 7 is a diagram showing the relationship between the infinite transmission mechanism unit U and the engine E of the present invention, and FIG. And is a graph of rate showing the relationship of the subtransmission mechanism.
[0010]
The configuration of the infinite transmission mechanism unit U of the present invention will be described with reference to FIGS. 1, 7, and 8. FIG. The output from the engine E is transmitted to the flywheel 15 in the clutch housing H. A shock absorber B is interposed at the rear part of the flywheel 15 and is transmitted to the engine output shaft 1. The engine output shaft 1 also serves as the pump shaft of the variable displacement pump P. The engine output shaft 1 drives and rotates the variable displacement pump P and discharges variable pressure oil. The engine output shaft 1 projects to the rear of the variable displacement pump P and passes through the PTO intermediate shafts 4 and 5. The rotation after the two-speed shift is transmitted to the PTO shaft 6 projecting from the rear part of the transmission case MC. Between the PTO intermediate shaft 4 and the PTO intermediate shaft 5, a PTO clutch N for connecting / disconnecting PTO power is interposed.
[0011]
The infinite transmission mechanism unit U of the present invention includes a variable displacement pump P interposed on the engine output shaft 1 and a variable displacement motor on a continuously variable transmission output shaft 2 arranged in parallel with the engine output shaft 1. It is comprised by M1 and the fixed capacity | capacitance motor M2. An oil passage plate 7 is configured to send the pressure oil from the variable displacement pump P to the variable displacement motor M1 and the fixed displacement motor M2, and a variable displacement is provided on the transmission case MC side of the oil passage plate 7. A pump P and a variable displacement motor M1 are attached, and a fixed displacement motor M2 is attached on the engine E side of the oil passage plate 7. The main transmission operating mechanism 9 operates the movable swash plate of the variable displacement pump P and can be configured by a pedal or a lever. In FIG. 6, the main speed change operation mechanism 9 is composed of two pedals 9, one of which is a forward pedal and the other is a reverse pedal. Further, the sub-transmission operation mechanism 8 operates the movable swash plate of the variable capacity motor M1, and is constituted by the sub-transmission lever 8 in FIG.
[0012]
As shown in FIG. 7, an infinite transmission mechanism unit U is configured. The infinite transmission mechanism unit U transmits the power from the engine E to the variable displacement pump P through the engine output shaft 1, and operates the movable swash plate of the variable displacement pump P by the main transmission operation mechanism 9. The pressurized oil is supplied to the variable displacement motor M1 and the fixed displacement motor M2. By the operation of the movable swash plate of the variable displacement pump P by the main transmission operation mechanism 9, the main transmission mechanism of the continuously variable transmission output shaft 2 is changed. Further, the pressure oil discharged from the variable displacement pump P is supplied to the variable displacement motor M1 and the fixed displacement motor M2 through the oil passage plate 7, and the movable swash plate of the variable displacement motor M1 is connected to the auxiliary transmission lever 8. , The rotation of the continuously variable transmission output shaft 2 is shifted by the auxiliary transmission mechanism.
[0013]
The main speed change mechanism by operating the movable swash plate of the variable displacement pump P by the main speed change operation mechanism 9 is a speed change in which forward and reverse forward and reverse rotations are performed as shown by a linear curve 30 in FIG. On the other hand, the shift performed by operating the movable swash plate of the variable displacement motor M1 by the sub-shift lever 8 is a shift whose angle changes like the linear curves 31 and 32 in which the angle of the linear curve 30 is changed in FIG. It is done. Thus, both the main transmission mechanism by the main transmission operating mechanism 9 that operates the movable swash plate of the variable displacement pump P and the auxiliary transmission mechanism that operates the movable swash plate of the variable displacement motor M1 by the auxiliary transmission lever 8 are infinite. Since it is built in the transmission mechanism unit U and is performed by the variable displacement pump P, the variable displacement motor M1, and the fixed displacement motor M2, a gear-type transmission mechanism is not necessary.
[0014]
In FIG. 7, for example, the variable displacement pump P has a maximum discharge capacity of +37 to −37 cc, the variable displacement motor M1 has a discharge capacity of +42 to −19 cc, and the fixed displacement motor M2 has a fixed discharge capacity of 42 cc. Even between P and the hydraulic motor, TOTAL CAPACITY is +84 to +23. That is, by giving an oil pressure for rotating the fixed displacement motor M2 in the reverse direction to the variable displacement motor M1, a numerical value of + 42-19 = 23 cc is obtained. Thereby, the ratio of 84:23 can be reduced. Since the fixed displacement motor M2 has a fixed swash plate, it can only rotate in the forward and reverse directions determined by the movable swash plate of the variable displacement pump P. However, the movable displacement swash plate of the variable displacement motor M1 can freely rotate the sub-shift lever. 8 can be rotated independently of the movable swash plate of the variable displacement pump P. Therefore, the movable swash plate is controlled in a direction to give a rotational force opposite to the rotation of the fixed displacement motor M2, and the rotation of the variable displacement motor M1 is controlled. As a result, the rotation of the continuously variable transmission output shaft 2 is reduced.
[0015]
When the swash plates of the variable displacement motor M1 and the fixed displacement motor M2 have the same angle as a result of the operation of the auxiliary transmission lever 8, they rotate without any resistance of the motors. By operating the movable swash plate of the variable capacity motor M1 by the above operation, the rotation of the continuously variable transmission output shaft 2 changes in the forward / reverse / high / low direction. Therefore, it is expressed as an infinite transmission mechanism unit U.
[0016]
In FIG. 1, an embodiment of a continuously variable transmission mechanism for an agricultural tractor will be described. In the case of FIG. 1, an infinite transmission mechanism unit U composed of an oil passage plate 7, a variable displacement pump P, a variable displacement motor M <b> 1, and a fixed displacement motor M <b> 2 is fixedly arranged inside the clutch housing H. The clutch housing H is fixed to the rear part of the engine E, and the transmission case MC is fixed to the rear surface of the clutch housing H to constitute the main frame of the tractor. Power from the continuously variable transmission output shaft 2 is transmitted to the intermediate shaft 21 and then transmitted from the intermediate shaft 22 to the bevel gear shaft 23. The bevel gear shaft 23 transmits power to the differential gear mechanism D.
[0017]
Further, a front wheel drive intermediate shaft 24 that is gear-transmitted below the bevel gear shaft 23 is disposed, and power is transmitted from the front wheel drive intermediate shaft 24 to the front wheel power transmission shaft 26 via the front wheel drive clutch shaft 25. . In the embodiment of FIG. 1, a mid PTO intermediate shaft 14 is disposed below the PTO shaft 6, and power is transmitted from the mid PTO intermediate shaft 14 to the mid PTO shaft 13.
[0018]
In the embodiment of FIG. 2, the main clutch mechanism A is arranged at the rear part of the flywheel 15 in the clutch housing H. Power is connected to the engine output shaft 1 from the main clutch mechanism A. The infinite speed change mechanism unit U is the same in that it is composed of a variable displacement pump P, a variable displacement motor M1, and a fixed displacement motor M2 with the oil passage plate 7 as the center. However, the front end of the infinite transmission mechanism unit U is fixed to the front end of the transmission case MC, and the front end of the fixed capacity motor M2 of the infinite transmission mechanism unit U is disposed at the front end position where it is likely to hit the main clutch mechanism A. The total length of the tractor is shortened. The front wheel drive clutch shaft 25 that is gear-transmitted is disposed below the bevel gear shaft 23, and the front wheel power transmission shaft 26 is connected to the tip of the front wheel drive clutch shaft 25.
[0019]
In the embodiment shown in FIG. 3, the infinite transmission mechanism unit U is fixed to the front end of the transmission case MC, and is not disposed inside the clutch housing H. An airframe frame 10 is configured as an airframe support in place of the clutch housing H, and an engine E provided with a clutch housing H ′ and a transmission case MC are connected by the two airframe frames 10. Other configurations are substantially the same as those in FIGS. 1 and 2.
[0020]
4, the movable swash plate operating arm 16 of the variable displacement pump P in the infinite transmission mechanism unit U and the movable swash plate operating arm 17 of the variable displacement motor M1 are illustrated. The movable swash plate operating arm 17 and the movable swash plate operating arm 16 are arranged at the left and right positions of the mission case MC. In FIG. 5, a portion of the infinite transmission mechanism unit U at the front of the mission case MC is shown from the front. Also in FIG. 5, the movable swash plate operation arm 16 and the movable swash plate operation arm 17 are shown in the left and right positions. The upper shaft is the engine output shaft 1 and the lower shaft is the continuously variable transmission output shaft 2. Below that, the shaft centers of the front wheel drive clutch shaft 25 and the front wheel power transmission shaft 26 are located.
[0021]
FIG. 6 shows an arrangement configuration of the steering handle 11, the seat 12, the main transmission operating mechanism 9, and the auxiliary transmission lever 8. In the continuously variable transmission mechanism of the agricultural tractor according to the present invention, a gear type transmission is provided. The main transmission mechanism and the auxiliary transmission mechanism are both configured by the infinite transmission mechanism unit U. Therefore, the main transmission operating mechanism 9 and the auxiliary transmission lever 8 can be operated without operating the main clutch mechanism A. The operation of the main speed change mechanism 9 shifts the linear curve 30 in FIG. 8, and the operation of the auxiliary speed change lever 8 changes the angles of the linear curves 31 and 32 in FIG.
[0022]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
As in claim 1, an infinite transmission mechanism unit (U) is interposed in a transmission for an agricultural tractor, and the infinite transmission mechanism unit (U) includes a variable displacement pump (P), a variable displacement motor (M1), and a fixed displacement. The motor (M2) and the oil passage plate (7) are configured to transmit the power from the engine (E) to the variable displacement pump (P), and the movable swash plate of the variable displacement pump (P) is connected to the main speed change operation mechanism (9 ) To supply the variable pressure oil to the variable displacement motor (M1) and the fixed displacement motor (M2), and the main transmission operation mechanism (9) of the movable swash plate of the variable displacement pump (P). By the operation, the main transmission of the continuously variable transmission output shaft (2) is performed, and the pressure oil discharged from the variable displacement pump (P) is connected to the variable displacement motor (M1) and the fixed displacement via the oil passage plate (7). Supplied to motor (M2), variable capacity motor (M1) possible The swash plate is operated by the sub-transmission lever (8) to perform sub-transmission of the continuously variable transmission output shaft (2), and the movable swash plate of the variable displacement pump (P) is operated by the main transmission operation mechanism (9). The main transmission mechanism shifts along the linear curve (30) so that the forward and reverse rotations are performed, and operates the movable swash plate of the variable capacity motor (M1) by the auxiliary transmission lever (8). The sub-shift is performed by changing the angle of the linear curve (30) with the linear curve (31, 32), and without turning off the power from the engine (E). Since the speed change operation mechanism (9) or the sub speed change lever (8) can be operated continuously or separately continuously , a gear type speed change mechanism is installed in the speed change path of the tractor as in the prior art. There is no need to provide it as an auxiliary transmission mechanism Only limited transmission mechanism unit U, it became possible to perform the main transmission and sub transmission.
[0023]
Further, in the continuously variable transmission mechanism of the agricultural tractor, even when the main transmission operation mechanism 9 of the main transmission mechanism constituted by the infinite transmission mechanism unit U is operated, the auxiliary transmission lever 8 is operated without operating the main clutch. Therefore, the conventional tractor is configured with an HST transmission for the main transmission, and the sub-transmission operation is possible even if the main transmission operation can be performed with a non-clutch operation. Although the main clutch needs to be connected / disconnected, the present invention makes it possible to operate the main gear shift and the sub gear shift at the same time or in parallel in a non-clutch operation state.
[0024]
Further, in the continuously variable transmission mechanism of the agricultural tractor, the infinite transmission mechanism unit U portion is directly connected to the engine output shaft or via the main clutch device, so that there is another transmission mechanism between the engine E and the infinite transmission mechanism unit U. Since the gear-type transmission mechanism is not interposed, the main transmission mechanism constituted by the infinite transmission mechanism unit U and the auxiliary transmission mechanism can be directly operated without connecting / disconnecting the main clutch. is there.
[0025]
In the continuously variable transmission mechanism of an agricultural tractor as in claim 2, since the infinite transmission mechanism unit U is housed in the clutch housing H interposed between the engine E and the transmission case MC, the interior of the transmission case MC In this case, it is only necessary to arrange the differential gear device D, the mission case MC can be reduced in size, and the infinite transmission mechanism unit U is disposed in the dead space of the clutch housing H constituting the fuselage frame. The tractor can be made compact.
[0026]
In the continuously variable transmission mechanism of an agricultural tractor as in claim 3, an infinite transmission mechanism unit U is attached to the front portion of the transmission case MC in which the differential gear mechanism D is housed, and the machine body between the engine E and the transmission case M is provided. Since it is connected by the frame 10, it can also be configured as a frame type tractor without the clutch handling H interposed between the engine E and the transmission case MC, so that a low-cost tractor can be obtained.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a configuration of a continuously variable transmission mechanism of an agricultural tractor according to the present invention.
FIG. 2 is a side cross-sectional view showing a configuration in which an infinite transmission mechanism unit U is attached to the front surface of a mission case MC to shorten the length of the continuously variable transmission mechanism.
FIG. 3 is a side cross-sectional view of an embodiment in which an infinite transmission mechanism unit U is attached to the front end of a transmission case MC, and a large connecting clutch housing is eliminated and the airframe is configured by an airframe frame 10;
4 is a plan view showing a clutch housing H and a transmission case MC of the embodiment of FIG.
FIG. 5 is a front view of an infinite transmission mechanism unit U.
6 is a plan view showing an arrangement of a main speed change operation mechanism 9, a sub speed change lever 8, a seat 12, and a steering handle 11. FIG.
FIG. 7 is a view showing the relationship between an infinite transmission mechanism unit U and an engine E according to the present invention.
FIG. 8 is a speed graph showing the relationship between the main transmission mechanism and the subtransmission mechanism by the infinite transmission mechanism unit U.
[Explanation of symbols]
A Main clutch device U Infinite transmission mechanism unit P Variable displacement pump M1 Variable displacement motor M2 Fixed displacement motor H Clutch housing 8 Sub transmission lever 9 Main transmission operation mechanism 10 Airframe frame

Claims (3)

An infinite transmission mechanism unit (U) is interposed in the transmission of an agricultural tractor, and the infinite transmission mechanism unit (U) includes a variable displacement pump (P), a variable displacement motor (M1), a fixed displacement motor (M2), and an oil. It is composed of a road plate (7), transmits power from the engine (E) to the variable displacement pump (P), and operates the movable swash plate of the variable displacement pump (P) by the main transmission operating mechanism (9). The variable pressure oil is supplied to the variable displacement motor (M1) and the fixed displacement motor (M2), and the main transmission operation mechanism (9) operates the movable swash plate of the variable displacement pump (P) to continuously change the speed. The main transmission of the output shaft (2) is performed, and the pressure oil discharged from the variable displacement pump (P) is supplied to the variable displacement motor (M1) and the fixed displacement motor (M2) via the oil passage plate (7). Then, move the movable swash plate of the variable displacement motor (M1) -A main transmission mechanism that is operated by (8), performs sub-transmission of the continuously variable transmission output shaft (2), and operates the movable swash plate of the variable displacement pump (P) by the main transmission operation mechanism (9). Is a sub-shift that is performed by operating the movable swash plate of the variable displacement motor (M1) by the sub-shift lever (8), performing a shift that performs forward and reverse forward and reverse rotation along the linear curve (30). Shifts the angle of the linear curve (30) according to the linear curve (31, 32), and the main transmission operation mechanism (9) without turning off the power from the engine (E). ) Or the sub-transmission lever (8) can be operated at the same time or separately . The continuously variable transmission mechanism for an agricultural tractor according to claim 1, wherein the infinite transmission mechanism unit (U) is installed in a clutch housing (H) interposed between the engine (E) and the transmission case (MC). A continuously variable transmission mechanism for agricultural tractors. A continuously variable transmission mechanism for an agricultural tractor according to claim 1, wherein the infinite transmission mechanism unit (U) is attached to a front portion of a transmission case (MC) in which a differential gear mechanism (D) is installed, and the engine (E) and the transmission A continuously variable transmission mechanism for an agricultural tractor characterized in that the case (MC) is connected to the case (MC) by an airframe frame (10) .

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