JP4521113B2 - transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique in which a hydraulic continuously variable transmission is provided as a transmission of a traveling vehicle, the hydraulic continuously variable transmission is disposed on one shaft, and a forward / reverse switching device is disposed at the rear thereof.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a transmission having a hydraulic continuously variable transmission, a cylinder block is fixed on the output shaft of the engine or the input shaft of the transmission, and a plurality of plungers for pumps and motors are attached to the cylinder block with respect to the output shaft. The pump plunger head protruding from the cylinder block is in contact with the movable swash plate, and the motor plunger head protruding from the cylinder block is loosely fitted onto the output shaft. Place it in contact with the swash plate. Then, power is taken out from the output body to which the fixed swash plate is attached, the cylinder block is rotated by the power from the engine, and the angle of the movable swash plate is changed to change the rotational speed of the output body. The technology is known.
[0003]
[Problems to be solved by the invention]
However, when the transmission is mounted on a traveling vehicle, it is necessary to be able to move forward and backward. However, in the transmission, it is difficult to generate reverse rotation, and the speed change mechanism is complicated.
[0004]
Accordingly, the present invention is provided with a forward / reverse switching device integrally provided on the output side of the hydraulic continuously variable transmission so that the gear can be shifted over a wide range and can be switched with a simple configuration.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention solves the problems by the following means.
[0006]
The input shaft (31) of the hydraulic continuously variable transmission (20) is connected to the output shaft (30) of the engine (5), and the forward / reverse switching device (21) is disposed in the hydraulic continuously variable transmission (20). The hydraulic continuously variable transmission (20) is configured integrally with a variable hydraulic device (32) and a differential hydraulic device (33), and the piston (40...) Of the variable hydraulic device (32) The cylinder block (34) is arranged on the same circumference around the input shaft (31) of the hydraulic continuously variable transmission (20) and is spline-fitted onto the input shaft (31). The piston (40...) Of the variable hydraulic device (32) is slidably accommodated, and is disposed so as to be retractable from one side of the cylinder block (34), and the piston (40) of the variable hydraulic device (32). ..) the head abuts against the movable swash plate (35), and the movable swash plate (35) The hydraulic continuously variable transmission (20) is arranged so as to be rotatable in an arc shape around one point of the axis of the input shaft (31), and is interlocked with the forward / reverse switching operation tool (13). The pistons (41,...) Of the dynamic hydraulic device (33) are slidably accommodated in the same cylinder block (34), and the pistons (41,...) Of the differential hydraulic device (33) are The head of the piston (41...) Of the differential hydraulic device (33) is disposed so as to be retractable from the other side of the cylinder block (34), and abuts against the fixed swash plate or the movable swash plate (36). Alternatively, the pistons (40,...) Of the variable hydraulic device (32) and the pistons (41,...) Of the differential hydraulic device (33) are arranged on the circumference inside and outside the same cylinder block (34). arranged so as not to overlap with, projecting in opposite directions, the front and rear In which switching device (21) hydraulic stepless transmission and (20) were a single unit.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment in which the transmission of the present invention is mounted on a tractor will be described with reference to the drawings.
[0008]
1 is an overall side view of a tractor, FIG. 2 is a skeleton diagram showing a power transmission system, FIG. 3 is a sectional view of a transmission of the present invention, FIG. 4 is a skeleton diagram showing another embodiment of a forward / reverse switching device, and FIG. Fig. 6 is a cross-sectional view of a transmission in which the forward / reverse switching device is configured with a hydraulic clutch, Fig. 6 is a skeleton diagram in which the forward / reverse switching device is detachable, and Fig. 7 is a part of the forward / reverse switching device housed in the mission case FIG. 8 is a diagram showing the relationship between the angle of the movable swash plate and the rotational speed.
[0009]
In FIG. 1, an embodiment in which a traveling vehicle is a tractor, and the hydraulic continuously variable transmission 20 and the forward / reverse switching device 21 of the present invention are mounted on the tractor will be described from the overall configuration. A front wheel 1 and a rear wheel 2 are supported before and after the main body of the traveling vehicle, an engine 5 serving as a driving source is disposed inside the front bonnet 6, and a steering handle 10 is disposed with the rear of the bonnet 6 as an operation unit. A seat 11 is disposed behind the steering handle 10. A forward / reverse pedal 13 serving as a forward / reverse switching operation tool that enables forward / reverse switching and shifting is disposed on a step 12 disposed below the seat 11 and the steering handle 10. A sensor 16 for detecting the rotation of the forward / backward pedal 13 is disposed at the base of the forward / backward pedal 13. It is connected to the actuator 18 that rotates (FIG. 2). However, a lever, a volume, or the like can be used instead of the pedal as means for operating forward / reverse switching and shifting. Further, there is no limitation as long as rotation to the forward side or the reverse side can be detected by a switch or the like instead of the sensor. The actuators 17 and 18 can be constituted by cylinders, motors, or the like, but can be interlocked and connected via a link or the like without using an actuator.
[0010]
2 and 3, the rear end of the output shaft 30 of the engine 5 is connected to the input shaft 31 of the hydraulic continuously variable transmission 20 via a damper or a clutch, and forward / reverse switching is performed to the rear portion of the hydraulic continuously variable transmission 20. The device 21 is disposed, and the differential device 22 is disposed at the rear thereof, and the rear wheel 2 is driven from the differential device 22. Further, the front wheel 1 can be driven from the output shaft 50 of the forward / reverse switching device 21 via a front wheel drive switching device (not shown). These hydraulic continuously variable transmission 20, forward / reverse switching device 21, differential device 22, and front wheel drive switching device are housed in mission case 9. However, as shown in FIG. 7, the hydraulic continuously variable transmission 20 and the forward / reverse switching device 21 are integrally provided as a unit, and a part of the forward / backward switching device 21 is accommodated in the mission case 9. It is also possible. Although the speed is reduced to some extent by the forward / reverse switching device 21, it is also possible to provide a sub-transmission device in the subsequent stage of the output shaft 50 so that the reduction ratio can be changed.
[0011]
A PTO shaft 15 is connected to the rear end of the input shaft 31. The PTO shaft 15 protrudes rearward from the rear end of the transmission case 9, and the rear end of the machine body is connected to the rear end of the aircraft through a universal joint (not shown). The work machine mounted via the work machine mounting apparatus provided on the machine is driven. However, as shown in FIG. 6, a PTO clutch 23 or a PTO transmission (not shown) may be provided between the rear end of the input shaft 31 and the PTO shaft 15.
[0012]
Next, the configuration of the power transmission system will be described. The hydraulic continuously variable transmission 20 includes a variable hydraulic device 32 and a differential hydraulic device 33, in other words, a variable hydraulic device 32 that projects and projects a piston by a stationary contact member, and an input by projecting and projecting a piston. It comprises a differential hydraulic device 33 having an output rotating portion that performs either relative or synchronous rotation with respect to rotation. In the present embodiment, the variable hydraulic device 32 is constituted by an axial piston type variable displacement type hydraulic pump, and the differential hydraulic device 33 is constituted by an axial piston type fixed displacement type hydraulic motor. As shown in FIG. 4, the hydraulic device 33 can be of a variable displacement type.
[0013]
The variable hydraulic device 32 and the differential hydraulic device 33 are integrally provided on the input shaft 31, and the hydraulic continuously variable transmission 20 and the forward / reverse switching device 21 are housed in a case 25 that is divided forward and backward. It is configured as one unit. Although not shown, the case 25 can be divided vertically or horizontally. In addition, a trochoid charge pump 26 is provided on the input shaft 31 to supply hydraulic oil in the closed circuit of the variable hydraulic device 32 and the differential hydraulic device 33. It is also possible. In this way, by configuring the hydraulic continuously variable transmission 20 and the forward / reverse switching device 21 as one unit, it is easy to assemble when mounted on a vehicle, a work machine or the like, and can be easily retrofitted. It can be configured compactly.
[0014]
The pistons (or plungers) 40, 40 ... of the variable hydraulic device 32 and the pistons (or plungers) 41, 41 ... of the differential hydraulic device 33 are slidably housed in the same cylinder block 34, respectively. The cylinder block 34 is spline-fitted onto the input shaft 31. In addition, the pistons 40, 40. The heads of the pistons 40, 40... Are in contact with a movable swash plate 35, and the movable swash plate 35 is disposed so as to be rotatable in an arc shape around one point of the axis of the input shaft 31. The swash plate 35 is linked to the forward / reverse pedal 13.
[0015]
The pistons 41, 41... Of the differential hydraulic device 33 are arranged so as to be able to move out and withdraw from the other side of the cylinder block 34. The fixed swash plate 36 is attached via a bearing to an output gear 37 serving as an output body that is rotatably supported on the input shaft 31 via a bearing. In this way, the piston 40 and the piston 41 are arranged so as to protrude in opposite directions, and are arranged so as not to overlap on the circumference, thereby forming a compact configuration. Further, the gear ratio can be changed by changing the capacity that can be accommodated in the piston 40 and the piston 41 or in the cylinder.
[0016]
Further, a communication oil passage 39 is formed in the cylinder block 34 between the piston 40 and the piston 41, and control valves 42 are respectively arranged at the entrances and exits of the hydraulic oil from the pistons 40 to the communication oil passage 39. The control valve 42 is configured in a plunger shape so as to be capable of withdrawing and withdrawing, and an end of the control valve 42 is in contact with the cam 43 via a bearing. The cam 43 reciprocally slides the control valve 42 to control the supply and discharge of hydraulic oil. The cam 43 is fixed to a receiver 44 that guides the movable swash plate 35.
[0017]
Further, a control valve 45 is provided between each piston 42 and the communication oil passage 39 on the differential hydraulic device 33 side, and the control valve 45 is configured in a plunger shape so as to be able to move in and out of the cylinder block 34. The tip of the control valve 45 is brought into contact with a cam 46 through a bearing. The cam 46 reciprocates and slides the control valve 45 to control the supply and discharge of hydraulic oil, and is loosely fitted on the input shaft 31. It is fixed to the output gear 37.
[0018]
In this way, the variable hydraulic device 32 and the differential hydraulic device 33 form a closed circuit via the communication oil passage 39, and the supply of pressure oil into the closed circuit is provided at the shaft core of the input shaft 31. Pressure oil is supplied from the charge pump 26 through the oil passage 31a. The charge pump 26 is disposed on the input shaft 31, but can be disposed on another shaft. Further, although a pump case is provided outside the case 25 and stored, the charge pump 26 can be configured in the case 25.
[0019]
In such a configuration, when the input shaft 31 is rotated, the cylinder block 34 fixed to the input shaft 31 is rotated, and the pistons 40, 40,.・ Slides back and forth and hydraulic oil is discharged.
[0020]
That is, when the movable swash plate 35 is at a position perpendicular to the input shaft 31, that is, when it is neutral (neutral), the pistons 40, 40. There is no movement of hydraulic oil. When the movable swash plate 35 is tilted, the pistons 40, 40... Slide out and retract, and by extending (advancing), the hydraulic oil is sucked into the piston 40 and contracting (retracting). By doing so, the hydraulic oil in the piston 40 is discharged. Switching is performed by the control valve 42 so that the hydraulic oil is sucked from the low-pressure side oil passage at the time of suction and discharged to the high-pressure side oil passage at the time of discharge. The intake timing or the discharge timing can be changed by an operation such as replacing or rotating the cam 43 in contact with the control valve 42. Further, as the tilt angle of the movable swash plate 35 is increased, the discharge amount can be increased and the gear ratio can be increased.
[0021]
On the other hand, the hydraulic oil is supplied to the piston 41 of the differential hydraulic device 33, and the hydraulic oil is pumped to the piston 41 at the contracted position by the operation of the control valve 45 to extend the piston 41, and the fixed swash plate 36 is pushed to output the output gear 37. Rotate. By switching the control valve 45 from the most extended position, the pressure oil is not fed to the piston 41, and the hydraulic oil in the piston 41 is fed to the communication oil path on the low pressure side. The discharge timing can be changed by means such as replacing or rotating the cam 46. Further, by making the fixed swash plate 36 a movable swash plate, a variable displacement type differential hydraulic device can be obtained, and the gear ratio can be changed in a wider range.
[0022]
Next, the configuration of the forward / reverse switching device 21 will be described. The output body (output gear) 37 is composed of two gears, and a forward gear 51 and a reverse gear 52 are loosely fitted on an output shaft 50 that is rotatably mounted on the case 25 in parallel with the input shaft 31. The forward gear 51 meshes with one gear 37 a of the output gear 37, and the reverse gear 52 meshes with the other gear 37 b of the output gear 37 via a counter gear 53.
[0023]
The forward gear 51 and the reverse gear 52 are respectively formed with small gears 51 a and 52 a, and a spline collar 54 is fixed on the output shaft 50 between the forward gear 51 and the reverse gear 52. The slider 55 is slidably fitted to the slider 55, and the shifter 56 is engaged with the shifter 56. The shifter 56 is fixed to the operating rod 17 a of the actuator 17, and the slider 17 is slid by operating the actuator 17. The forward rotation is transmitted to the output shaft 50 by meshing with the small gear 51a, and the reverse rotation is transmitted to the output shaft 50 by meshing with the small gear 52a. In this way, the forward / reverse switching device 21 is configured. The forward / reverse switching device 21 is housed in a case 25 together with the hydraulic continuously variable transmission 20 and is compactly configured as one unit.
[0024]
However, the configuration of the switching unit including the slider 55 and the like of the forward / reverse switching device 21 is not limited to the above configuration, and can be provided in the output body 37 as shown in FIG. That is, the output body 37 is configured as a pipe-like spline shaft 37 ′, and the spline shaft 37 ′ is loosely fitted on the input shaft 31, and the forward gear 51 ′ and the reverse gear 52 ′ are placed on the spline shaft 37 ′. The slider 55 'is spline fitted between the forward gear 51' and the reverse gear 52 'so as to be freely slidable. The driven gears 61 and 62 are fixed on the output shaft 50 to mesh the forward gear 51 ′ with the driven gear 61, and the reverse gear 52 ′ is meshed with the driven gear 62 via the counter gear 53. It is also possible.
[0025]
Further, as shown in FIG. 5, hydraulic clutches 58 and 59 are provided in the forward gear 51 and the reverse gear 52, instead of the configuration in which the forward / backward movement is switched by sliding the slider or the gear, and the hydraulic clutch 58 · It can also be configured to switch back and forth by connecting and disconnecting 59. Further, although not shown, forward / backward movement can be switched by a synchromesh type, a ball clutch type, an electromagnetic clutch type, or the like, and is not limited.
[0026]
Further, as shown in FIG. 6, the hydraulic continuously variable transmission 20 and the forward / reverse switching device 21 can be housed in separate cases so as to be separable. By doing so, the hydraulic continuously variable transmission 20 and the forward / reverse switching device 21 are separately arranged in the mission case and attached at a position that does not interfere with other devices, thereby facilitating design changes. Can do. In addition, design changes such as retrofitting or changing only the main transmission can be easily performed.
[0027]
In FIG. 6, the output body 37 is a single gear 37 ″ that transmits power from the gear 37 ″ to a transmission gear 64 fixed on the switching shaft 63 and is a spline-fitted slider on the switching shaft 63. 55 'is slid and meshed with the forward gear 51 or the small gear 51a or 52a of the reverse gear 52 so that the forward / reverse movement can be switched.
[0028]
Further, in FIG. 3, the actuator 17 is constituted by a solenoid, and the actuator 17 is connected to a sensor 16 provided at the rotation base of the forward / reverse pedal 13 via a control circuit 19 so that the forward / backward pedal 13 is moved forward. The actuator 17 is extended when it is rotated to engage the slider 55 with the small gear 51 a of the forward gear 51, and when it is rotated in the reverse direction, the actuator 17 is reduced to a small gear of the reverse gear 52. 52a is engaged. However, the actuator 17 is not limited to a solenoid, and may be an electric cylinder or a motor.
[0029]
Moreover, as shown in FIG. 6, it can also be set as the structure which connects shifter 56 'with lever 13' as an operation tool using link 65 (or a rod, an arm, a wire, etc.). The forward / reverse pedal 13 is an operating tool such as a lever and is not limited.
[0030]
With the configuration as described above, the relationship with the rotational speed when the movable swash plate is rotated will be described with reference to FIG. When the forward / reverse pedal 13 is rotated forward, the sensor 16 detects the rotational direction, and the operation rod 17a is operated corresponding to the rotational direction of the actuator 17 to switch the forward / reverse switching device 21. . In this case, switch to the forward side.
[0031]
During the rotation, the movable swash plate 35 is rotated in the plus direction from the most minus angle in proportion to the rotation of the forward / reverse pedal 13. That is, the rotational speed of the output body (output gear) 37 when the movable swash plate 35 is neutral (angle 0) substantially matches the rotational speed of the output shaft 50 of the engine 5. Then, when rotating from the neutral position to the plus (forward) side, in addition to the rotation of the input shaft 31, the power shifted by the differential hydraulic device 33 is applied. That is, the speed is relatively increased with respect to the rotation of the output shaft 30.
[0032]
On the contrary, when the movable swash plate 35 is rotated from the neutral to the minus (reverse) side, in addition to the rotation of the input shaft 31, the power shifted by the differential hydraulic device 33 is rotated in the reverse direction. That is, the speed is relatively reduced. Then, the rotation from the engine 5 and the rotation from the differential hydraulic device 33 are offset at the most negative position, and the rotation of the output body 37 is stopped. In other words, the rotation speed of the output shaft 30 of the engine 5 is not increased in the negative shift region of the hydraulic continuously variable transmission 20. In other words, the rotation of the output body 37 is set so as not to rotate in the direction opposite to the rotation direction of the output shaft 30 of the engine by the speed change operation of the hydraulic continuously variable transmission 20.
[0033]
Further, when the forward / reverse pedal 13 is rotated backward, the sensor 16 detects the rotational direction, and operates the operating rod 17a corresponding to the rotational direction of the actuator 17, so that the forward / reverse switching device 21 is operated. To the reverse side. Then, the movable swash plate 35 is rotated in the plus direction from the most minus angle in proportion to the rotation of the forward / reverse pedal 13. Similarly to the above, the differential hydraulic device 33 is accelerated from the reverse rotation to the normal rotation direction. However, in this embodiment, the forward speed and the reverse speed are substantially the same gear ratio, but it is not necessary to increase the traveling speed to the reverse side, so the reverse speed ratio by changing the number of teeth etc. It can also be configured to be smaller than the forward side.
[0034]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
The input shaft (31) of the hydraulic continuously variable transmission (20) is connected to the output shaft (30) of the engine (5), and the forward / reverse switching device (21) is disposed in the hydraulic continuously variable transmission (20). The hydraulic continuously variable transmission (20) is configured integrally with a variable hydraulic device (32) and a differential hydraulic device (33), and the piston (40...) Of the variable hydraulic device (32) The cylinder block (34) is arranged on the same circumference around the input shaft (31) of the hydraulic continuously variable transmission (20) and is spline-fitted onto the input shaft (31). The piston (40...) Of the variable hydraulic device (32) is slidably accommodated, and is disposed so as to be retractable from one side of the cylinder block (34), and the piston (40) of the variable hydraulic device (32). ..) the head abuts against the movable swash plate (35), and the movable swash plate (35) The hydraulic continuously variable transmission (20) is arranged so as to be rotatable in an arc shape around one point of the axis of the input shaft (31), and is interlocked with the forward / reverse switching operation tool (13). The pistons (41,...) Of the dynamic hydraulic device (33) are slidably accommodated in the same cylinder block (34), and the pistons (41,...) Of the differential hydraulic device (33) are The head of the piston (41...) Of the differential hydraulic device (33) is disposed so as to be retractable from the other side of the cylinder block (34), and abuts against the fixed swash plate or the movable swash plate (36). Alternatively, the pistons (40,...) Of the variable hydraulic device (32) and the pistons (41,...) Of the differential hydraulic device (33) are arranged on the circumference inside and outside the same cylinder block (34). arranged so as not to overlap with, projecting in opposite directions, the front and rear Since switching device (21) hydraulic stepless transmission and a (20) was one unit, the forward-reverse switching device (21) and the hydraulic stepless transmission (20) and for is one unit compact It is possible to reduce the weight, increase versatility, and can be easily assembled to a vehicle or the like.
[Brief description of the drawings]
FIG. 1 is an overall side view of a tractor.
FIG. 2 is a skeleton diagram showing a power transmission system.
FIG. 3 is a cross-sectional view of the transmission of the present invention.
FIG. 4 is a skeleton diagram showing another embodiment of the forward / reverse switching device.
FIG. 5 is a cross-sectional view of a transmission in which the forward / reverse switching device is similarly configured by a hydraulic clutch.
FIG. 6 is a skeleton diagram in which a forward / reverse switching device is configured to be detachable.
FIG. 7 is a cross-sectional view of an embodiment in which a part of the forward / reverse switching device is housed in a mission case.
FIG. 8 is a diagram showing the relationship between the angle of the movable swash plate and the rotational speed.
[Explanation of symbols]
13 Forward / reverse switching operation tool (forward / reverse pedal)
DESCRIPTION OF SYMBOLS 20 Hydraulic type continuously variable transmission 21 Forward / reverse switching device 30 Output shaft 32 Variable hydraulic device 33 Differential hydraulic device 37 Output body (output gear)

Claims (1)

The input shaft (31) of the hydraulic continuously variable transmission (20) is connected to the output shaft (30) of the engine (5), and the forward / reverse switching device (21) is disposed in the hydraulic continuously variable transmission (20). The hydraulic continuously variable transmission (20) is configured integrally with a variable hydraulic device (32) and a differential hydraulic device (33), and the piston (40...) Of the variable hydraulic device (32) The cylinder block (34) is arranged on the same circumference around the input shaft (31) of the hydraulic continuously variable transmission (20) and is spline-fitted onto the input shaft (31). The piston (40...) Of the variable hydraulic device (32) is slidably accommodated, and is disposed so as to be retractable from one side of the cylinder block (34), and the piston (40) of the variable hydraulic device (32). ..) the head contacts the movable swash plate (35), and the movable swash plate (35) The hydraulic continuously variable transmission (20) is arranged so as to be rotatable in an arc shape around one point of the axis of the input shaft (31), and is interlocked with the forward / reverse switching operation tool (13). The pistons (41,...) Of the dynamic hydraulic device (33) are slidably accommodated in the same cylinder block (34), and the pistons (41,...) Of the differential hydraulic device (33) are The head of the piston (41...) Of the differential hydraulic device (33) is disposed so as to be retractable from the other side of the cylinder block (34), and abuts against the fixed swash plate or the movable swash plate (36). Alternatively, the pistons (40,...) Of the variable hydraulic device (32) and the pistons (41,...) Of the differential hydraulic device (33) are arranged on the circumference inside and outside the same cylinder block (34). arranged so as not to overlap with, projecting in opposite directions, the front and rear Transmission, wherein the switching device (21) hydraulic continuously variable transmission and (20) were a single unit.

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