JP2000318471A - Transmission for vehicle running - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission for vehicle running equipped with an HST (continuously variable transmission device) and a multi-stage transmission device capable of preventing the multi-stage transmission device from being applied with excessive load even when the multi-stage transmission device undergoes a shifting operation during vehicle running and smoothening the change of the vehicle speed when shifting operation is made. SOLUTION: A transmission for vehicle running is equipped with a planetary gearing device 30 consisting of a sun gear 31 coupled with the output from an HST 20 to be fed branchedly with the power from a drive source 100, a planet gear 32 to receive the power from the drive source, an outer ring 33 fitted with an internal gear to mesh with the planet gear, and a carrier 34 rotating in compliance with the revolutions of the planet gear, a multi-stage transmission device 40 coupled with the outer ring, and a lockup mechanism 50 to consolidate the carrier with the outer ring only in the period with shift operation of the multi-stage transmission device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling transmission interposed in a transmission path from a driving source to driving wheels, and more particularly, to a transmission having a continuously variable transmission (hereinafter referred to as HST) and a multi-stage transmission. It relates to a transmission for traveling.

[0002]

2. Description of the Related Art A traveling transmission including an HST and a multi-speed transmission is known, for example, as described in Japanese Patent Application Laid-Open No. 54-13131. The traveling transmission described in the above publication discloses that all power from the drive source is H
The multi-stage transmission is configured to input to the multi-stage transmission via ST, so that the multi-stage transmission can perform a multi-stage transmission, and the HST can perform a continuously variable transmission for each stage of the multi-stage transmission. Has become.

However, in the conventional traveling transmission, the shifting operation of the multi-stage transmission and the shifting operation of the HST are performed completely independently, so that the speed of the multi-stage transmission is shifted while the vehicle is running. Was not expected. That is, the conventional transmission for traveling, (1) When low-speed traveling such as during agricultural work is required, after previously putting the multi-stage transmission into the low-speed stage,
Operate the HST to drive the vehicle. (2) If high speed running such as when driving on public roads is required, stop the vehicle once, put the multi-stage transmission into the high speed stage, and operate the HST. It was intended to run the vehicle.

Accordingly, in the conventional traveling transmission, when the multi-stage transmission is shifted during traveling of the vehicle, the following inconvenience occurs. For example, in a state where the multi-speed transmission is engaged with the first speed, the HST is operated to increase the vehicle speed, and the multi-speed transmission is moved to the second speed as it is.
Consider a case where a shift operation is performed to a gear. When the multi-speed transmission is in the first speed, the highest speed is obtained by the HS
This is the case where the swash plate of T is swung to the maximum. Accordingly, in this state, when the multi-stage transmission is shifted up to the second speed, the multi-stage transmission is immediately shifted to the second speed in the maximum output state of the HST, and excessive load is applied to the multi-stage transmission. This caused a breakdown and caused a very poor ride quality.

[0005] Further, the conventional traveling transmission is configured such that all the power from the drive source passes through the HST. Therefore, the HST must have a capacity capable of receiving the full power of the drive source. Therefore, there is also a problem that the HST is increased in size and the cost is increased.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made in a traveling transmission provided with an HST and a multi-stage transmission.
Provided is a traveling transmission that can prevent an excessive load from being applied to a multi-stage transmission even when a shift operation of the multi-stage transmission is performed during traveling of a vehicle, and that can smoothly change a vehicle speed during the shift operation. With the goal.

Another object of the present invention is to provide a traveling transmission in which the HST can be downsized.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a transmission for driving a vehicle interposed in a transmission path from a drive source to a drive wheel, wherein the transmission is operatively connected to the drive source. A continuously variable transmission having a connected main drive shaft, and a hydraulic pump and a hydraulic motor, at least one of which is a variable displacement type, wherein a swash plate receives a motive power from the drive source via a branch input from the main drive shaft. And a sun gear operatively connected to an output shaft of the continuously variable transmission, and a non-rotatably connected to the main drive shaft. A planetary gear device including a carrier, a planetary gear that meshes with the sun gear and revolves in accordance with the rotation of the carrier, and an outer ring body provided with an internal gear that meshes with the planetary gear. Nire A multi-stage transmission having a driven shaft and a driven shaft disposed in parallel with the drive shaft, and performing a multi-stage transmission between the two shafts. A transmission for traveling of a vehicle provided with a lock-up mechanism for synchronously rotating the vehicle and the outer race.

Preferably, the swash plate is connected to a traveling speed change operation means, and the connection state is released only during a shift period of the multi-stage transmission.

[0010] More preferably, the vehicle further comprises a swing angle detecting device for detecting a swing angle of the traveling speed change operating means, and performs a shifting operation of the multi-stage transmission based on a signal from the swing angle detecting device. Together with the lock-up mechanism.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the traveling transmission according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a transmission path of a vehicle provided with the traveling transmission 1 according to the present embodiment. 2 and 3 are a hydraulic circuit diagram and a block diagram of a portion related to the traveling transmission 1, respectively.

The traveling transmission 1 is a traveling transmission for a vehicle interposed in a transmission path from a driving source 100 to a driving wheel 110, and includes a main driving shaft 10 operatively connected to the driving source 100. A continuously variable transmission 20 for branching and inputting the power from the drive source 100 from the main drive shaft 10, a planetary gear device 30 disposed downstream of the continuously variable transmission 20, and a planetary gear device 30. And a lock-up mechanism 50 acting on the planetary gear device 30. In FIG. 1, reference numeral 120 denotes a PTO shaft serving as a power take-out shaft of a towing work machine such as a rotary tilling device;
Numeral 0 denotes a power take-off shaft for the rear wheels, and numeral 150 denotes a mechanical forward / reverse switching mechanism.

The HST 20 includes a hydraulic pump 22 having an input shaft 21 and a hydraulic motor 24 having an output shaft 23. At least one of the hydraulic pump 22 and the hydraulic motor 24 can have a variable volume by a swash plate 25. It is a variable displacement type. In the present embodiment,
The hydraulic pump 22 is of a variable displacement type. The input shaft 21 of the HST 20 is connected to the main drive shaft 10 via gears 61 and 62, so that the drive source 100
A part of the power from the motor is branched and input from the main drive shaft 10 to the HST 20. On the other hand, the output shaft 23 of the HST 20 extends to the downstream side of the transmission path.

FIG. 4 is a cross-sectional view of the planetary gear device 30. As shown in FIG. As shown in FIGS. 1 and 4, the planetary gear device 30 includes a sun gear supported rotatably on the main drive shaft 10 and operatively connected to the output shaft 23 of the HST via a gear 63. A planetary gear 32 that meshes with the sun gear 31 and revolves around the sun gear; an outer ring body 33 provided with an internal gear that meshes with the planetary gear 32;
A carrier 34 that rotates according to the revolution of the planetary gear 32
And The carrier 34 is connected to the main drive shaft 10 so as not to rotate relatively.

The arrow in FIG. 4 shows an example of the relationship between the rotation direction of the planetary gear 32, the carrier 34, and the outer ring 33. This is because the main drive shaft 10 is rotated counterclockwise. In addition, this is a rotation direction when the HST output is reversely rotated with respect to the HST input. The rotation direction of each component of the planetary gear device 30 can be appropriately changed by the configuration of the power transmission mechanism and the setting of the forward / reverse rotation direction of the HST.

FIG. 5 is a longitudinal sectional view showing the vicinity of the planetary gear device 30, the lock-up mechanism 50, and the multi-speed transmission 40.
As shown in FIG. 1 and FIG.
The main drive shaft 1 is provided on the rear stage side of the planetary gear device 30.
0 supported.

As shown in FIG. 5, the lock-up mechanism 50 includes a first clutch member 51 which is connected to the outer race body 33 so as not to rotate relatively and is slidable in the axial direction of the main drive shaft 10. A second clutch member 52 supported by the main drive shaft 10 and the carrier 34 so as to be relatively non-rotatable and non-slidable in the axial direction;
And a biasing member 53 disposed between the clutch members 52. Then, by the action of the hydraulic pressure, the first clutch member 51 is pushed toward the second clutch member 52 against the urging force of the urging member 53, whereby the first clutch member 51 and the second clutch member 52 are pressed. Are configured to engage with each other.

As shown in FIG. 5, the multi-stage transmission 40 has a hollow drive shaft 41 having a shaft hole through which the main drive shaft 10 is inserted so as to be relatively rotatable. It comprises a driven shaft 42 disposed in parallel, and a plurality of power shift devices 43 for shifting between the drive shaft 41 and the driven shaft 42, and can perform multi-stage shifts between the drive shaft 41 and the driven shaft 42. It has become. In the present embodiment, four power shift devices 43 are provided,
The gear shift can be performed in four stages.

The reason why the drive shaft 41 is hollow is to transmit power from the rear end of the main drive shaft 10 to the PTO shaft 120. That is, as shown in FIG. 1, the main drive shaft 10 is penetrated through the shaft hole of the drive shaft 41, and power is transmitted from the rear end of the main drive shaft 10 to the PTO shaft 120. ing. Therefore, the PTO shaft 120
Is not required, or the PTO shaft 1
When transmitting power to the drive shaft 20, the drive shaft 41 can be solid.

The power shift devices 43 to 46 are fixed gears 43a to 46a which are supported by one of the drive shaft 41 and the driven shaft 42 so as not to rotate relatively, and a clutch device which is supported by the other shaft. 43b to 46b.

The clutch devices 43b to 46b are respectively provided with pushing members 43c to 46c supported on the other shaft so as to be relatively non-rotatable and slidable in the axial direction. It has loosely fitted gears 43d to 46d which are non-slidably supported and mesh with the fixed gears 43a to 46a. The pushing members 43c to 46c and the loosely fitted gears 43d to 46d are provided with corresponding clutch plates, respectively.

Further, the clutch devices 43b to 46b
Urging members 43e to 4e for urging the respective clutch plates of the pushing member and the free-fitting gear in a direction away from each other.
6e is provided, and is configured to engage / disengage the pushing plate and the clutch plate of the free-fitting gear by the action of hydraulic pressure.

The multi-stage transmission 40 has the above configuration, and the loose fitting gear 43d of the selected one power shift device is provided.
To 46d and fixed gears 43a to 46 corresponding to the loose fit gears.
A gear ratio corresponding to the ratio of the number of teeth to a is obtained between the drive shaft 41 and the driven shaft 42.

In this embodiment, as shown in FIGS. 1 and 5, the fixed gears 43a to 46a are provided on the drive shaft 41, and the clutch devices 43b to 46b are provided on the driven shaft 42. However, this is because the oil passages 79a to 79d and 91 for the multi-stage transmission and the oil passage 8 for the lock-up mechanism
4,87 is considered.

That is, in the present embodiment, as described above, in order to transmit power to the PTO shaft 120, the drive shaft 41
Is hollow. Therefore, if the clutch devices 43b to 46b are provided on the hollow drive shaft 41, the drive shaft 4
The oil passages 79a to 79d for the clutch device
It is necessary to form 91. As shown in FIG. 5, since the drive shaft 41 is also provided with oil passages 84 and 87 for the lock-up mechanism, the clutch devices 43b to 46 are provided on the drive shaft 41.
If b is provided, the thickness of the drive shaft 41 needs to be considerably increased. Accordingly, the outer diameter of the drive shaft 41 is increased, and accordingly, the distance between the drive shaft 41 and the driven shaft 42 is increased, and the multi-stage transmission 40 itself is increased in size.

On the other hand, as in the present embodiment, the clutch devices 43b to 46b are mounted on the solid driven shaft 42.
Is provided, the inconvenience does not occur, the size of the multi-stage transmission 40 can be reduced, and the formation of the oil passage can be facilitated, whereby the cost can be reduced.

Next, a hydraulic circuit of the multi-stage transmission 40 and the lock-up mechanism 59 will be described mainly with reference to FIG.

First, a hydraulic circuit 70 for the multi-stage transmission 40
Will be described. The hydraulic circuit 70 includes a multi-stage transmission hydraulic pump 71 that suctions oil from an oil tank 90 and discharges pressure oil, and a multi-stage transmission pressure oil line 72 through which pressure oil discharged from the hydraulic pump 71 flows. It has. The pressure oil line 72 is branched to a lubrication oil line 73 at a stage subsequent to a relief valve 75a that sets the operating oil pressure of the pressure oil line. The lubricating oil line 73 is connected to each power shift device 43
To supply lubricating oil to. In the figure, reference numeral 75b denotes a relief valve for setting the lubricating oil pressure of the lubricating oil line 73.

On the other hand, the pressure oil line 72 is connected to the first electromagnetic proportional valve 7.
6, and can be connected to the hydraulic oil line 77.
The hydraulic oil line 77 is branched into four at the rear stage.
The first electromagnetic proportional valve 76 has a function of preventing a sudden increase in the hydraulic pressure of the hydraulic oil line 77 when the pressure oil line 72 and the hydraulic oil line 77 are connected.

The branched rear ends of the hydraulic oil line 77 are connected to first to fourth power shift devices 43 to 46 at the rear ends through first to fourth switching valves 78a to 78d, respectively. Four suction lines 79a to 79d are connected. The first to fourth switching valves 78a to 78d are respectively
The hydraulic oil line 77 is connected to the first to fourth suction lines 79a to 79
d, and the first to fourth suction lines 7
9a to 79d are connected to a discharge line 91 for a pressure oil discharge position. In the drawing, reference numeral 77a is a pressure sensor for detecting the hydraulic pressure of the hydraulic oil line 77. Reference numeral 91a denotes a flow control valve interposed in the discharge line 91 for preventing a rapid decrease in oil pressure in the suction line 79 connected to the discharge line 91.

Next, the hydraulic circuit 80 for the lock-up mechanism 50 will be described. The hydraulic circuit 80 includes the oil tank 9
The hydraulic pump 81 includes a lock-up mechanism hydraulic pump 81 that sucks oil from 0 and discharges pressure oil, and a lock-up mechanism pressure oil line 82 through which the pressure oil discharged from the hydraulic pump 81 flows. The pressure oil line 82 is branched to a lubricating oil line 83 at a stage subsequent to a relief valve 85a for setting the operating oil pressure of the pressure oil line. The lubricating oil line 83 is for supplying lubricating oil to the lock-up mechanism 50.
In the drawing, reference numeral 85b denotes a relief valve for setting the lubricating oil pressure of the lubricating oil line 83.

On the other hand, the pressure oil line 82 is connected via a second electromagnetic proportional valve 86 to a hydraulic oil line 84 whose rear end is connected to the lockup mechanism 50. The second electromagnetic proportional valve 86 has a suction position for connecting the hydraulic oil line 84 and the pressure oil line 82 and a discharge position for connecting the hydraulic oil line 84 and the discharge line 87.
As in the case of No. 6, when the pressure oil line 82 is connected to the hydraulic oil line 84, the hydraulic oil line 82 has a function of preventing a sudden increase in the hydraulic pressure of the hydraulic oil line 84.

Next, an interlocking mechanism between the components of the traveling transmission according to the above configuration will be described mainly with reference to FIG.
This will be described with reference to FIG. In FIG. 3, reference numeral 26 denotes a pump displacement control shaft, and the swash plate of the hydraulic pump 22 swings with the rotation of the shaft. FIG. 6 shows A in FIG.
FIG.

As shown in FIGS. 3 and 6, the pump displacement control shaft 26 supports one end of an electromagnetic clutch 27 and a shifter 28. One end of the shifter 28 is rotatable relative to the pump displacement control shaft 26. on the other hand,
The electromagnetic clutch 27 cannot rotate relative to the shaft 26. An iron plate 29 is provided between the electromagnetic clutch 27 and the shifter 28, the iron plate 29 being rotatable relative to the shaft 27 and slidable in the axial direction, and non-rotatable relative to the shifter 28. Have been.

With this configuration, the iron plate 29 is normally attracted to the electromagnetic clutch 27 by the action of an electromagnet to engage the shifter 28 with the pump displacement control shaft 26, and when the cutting signal is input, the iron plate 29 is Electromagnetic clutch 2
7 and the shifter 28 and the pump displacement control shaft 2
6 is disengaged. That is, usually
The shifter 28 and the pump displacement control shaft 26 are interlocked via the electromagnetic clutch 27 and the iron plate 29, and when a disconnection signal is input to the electromagnetic clutch 27, the shifter 28 and the pump displacement control shaft 26 become relatively rotatable. Become.

The other end of the shifter 28 is connected to the link mechanism 1
Via 30, it is connected to a traveling speed change operation means provided near the driver's seat. In the present embodiment, a shift lever 140 is used as the traveling shift operation means. That is, with the swing of the shift lever 140, the other end of the shifter 28 swings around the pump displacement control shaft 26. When the shift lever 140 is in the neutral position (the N position in FIG. 3), the swash plate of the hydraulic pump 22 is also in the neutral position, and the output from the HST 20 is disabled. Further, the shift lever 140 is a mechanical forward / reverse switching mechanism 1 shown in FIG.
It is linked to 50. That is, the shift lever 1
When 40 is in the neutral position, the forward / reverse switching mechanism 150 is in the shut-off state, and the shift lever 140 is in the forward rotation region (in FIG. 3, the F1, F2, F3 and F4 regions).
The forward / reverse switching mechanism 150 engages the forward gear and the shift lever 140 swings to the reverse region (R1, R2, R3, and R4 regions in FIG. 3). Then, the forward / reverse switching mechanism 150 is adapted to engage the reverse gear.

Further, a potentiometer 131 connected to the controller 15 is provided on a shift lever support shaft which forms a part of the link mechanism 130, and when the swing angle of the shift lever 140 reaches a predetermined angle. , The controller 15 detects that fact.

In this embodiment, as described above, the multi-stage transmission 40 is of a four-stage type. Therefore,
Each of the HST forward rotation region and the HST reverse rotation region of the shift lever 140 is divided into four. That is, the forward rotation area is divided into the F1, F2, F3, and F4 areas, and the reverse rotation area is divided into the R1, R2, R3, and R4 areas. Then, when the shift lever 140 reaches the boundary point between the adjacent swing regions in the forward rotation region or the reverse rotation region, that is, at point a1 in the forward rotation region,
When reaching the points a2 and a3 or the points b1, b2 and b3 in the reverse rotation area, the controller 15 determines that.

Hereinafter, the case where the shift lever 140 is shifted from the (i) neutral state to the F1 region and further tilted in the F1 region (hereinafter referred to as case (i)), and
The transmission mechanism of the traveling transmission 1 will be described by taking, as an example, the case of (ii) shifting from the F1 region to the F2 region (hereinafter, referred to as case (ii)).

Case (i) When the shift lever 140 is in the neutral position, the forward / reverse switching mechanism 150 is shut off as described above. Therefore, the power from the drive source 100 is not transmitted to the drive wheels 110, and the vehicle remains stopped.

Next, when the shift lever 140 is swung to the F1 region, the potentiometer 131
Is detected, and the controller 15 determines that. In response to this, the controller 15 outputs a connection signal to the first electromagnetic proportional valve 76, and outputs the connection signal to the first switching valve 78.
A signal indicating that the pressure oil supply position is taken is output to a.

FIG. 7A shows a ratio of a change in the oil pressure of the hydraulic oil line 77 with respect to time. In FIG. 7A, the times corresponding to the swing positions a1, a2, and a3 of the shift lever are denoted by T1, T2, and T3.

As described above, the first electromagnetic proportional valve 76 prevents the hydraulic oil line 77 from suddenly increasing in oil pressure, so that the hydraulic oil line 77 and the first suction line 79 communicating therewith are prevented.
The hydraulic pressure at a gradually increases as shown by ON (1) in FIG. Therefore, it is possible to prevent the clutch plate of the power shift device 43 of the first speed stage, which is operated by the pressure oil from the first suction line 79a, from being rapidly engaged, thereby preventing the clutch plate from being damaged or abnormally worn. It can be effectively prevented.

On the other hand, while the shift lever 140 is in the F1 region, the controller 15 does not output signals to the second proportional solenoid valve 86 and the electromagnetic clutch 27. Therefore, the lock-up mechanism 50 remains in the disengaged state, and
The electromagnetic clutch 27 remains connected. As described above, when the electromagnetic clutch 27 is connected, the swash plate of the hydraulic pump 22 swings in conjunction with the shift lever 140. Therefore, as the shift lever 140 is inclined, the output of the HST 20 increases.

Here, the operation of the planetary gear device will be described mainly with reference to FIGS. As described above, the carrier 34 of the planetary gear device 30 is non-rotatably connected to the main drive shaft 10. Therefore, the planetary gear 32 of the planetary gear device always revolves at a constant speed and a constant speed by a part of the power from the driving source 100. The fixed direction is a counterclockwise direction in FIG.

On the other hand, the sun gear 31 of the planetary gear device is
As described above, it is connected to the output of HST20. Therefore, the rotation speed of the sun gear 31 increases as the output of the HST 20 increases. When the rotation speed of the carrier 34 (revolution speed of the planetary gear 32) is constant, the outer ring body 33 rotates at a higher speed as the rotation speed of the sun gear 31 increases.

FIG. 8 shows a vector diagram of the planetary gear set 30. FIGS. 8 (a) and 8 (b) show the shift lever 1 respectively.
FIG. 10 is a vector diagram when the angle 40 is slightly tilted and greatly tilted in the F1 region. Since the rotation speed vector of the outer race 33 is represented by a combination of the rotation speed vector of the sun gear 31 and the rotation speed vector of the carrier 34 (the revolution speed vector of the planetary gear device), FIGS. As shown in (), when the rotation speed vector of the carrier 34 is constant, the rotation speed vector of the outer race 33 increases as the rotation speed vector of the sun gear 31 increases.

As described above, when the shift lever 140 is located in the F1 region, the rotational speed of the outer ring 33 increases as the shift lever 140 is inclined. As described above, the outer race 33 is connected to the drive shaft 4 of the multi-speed transmission 40.
As the rotational speed of the outer race 41 increases, the vehicle speed also increases. FIG. 9 shows the relationship between the inclination angle of the swash plate of the hydraulic pump and the vehicle speed.

Case (ii) Next, the case where the shift lever 140 shifts from the F1 area to the F2 area, that is, the case where the shift lever reaches the point a1 in FIG. 3 will be described. In such a case, a signal to that effect is input from the potentiometer 131 to the controller 15.

In response to this, the controller 15 positions the first switching valve 78a at the pressure oil discharge position with respect to the multi-stage transmission 40, and once again shuts off the first electromagnetic proportional valve 76 and reconnects it. The second switching valve 78b is located at the pressure oil supply position.

As described above, since the discharge line 91 is provided with the flow control valve 91a, the first suction line 79
The oil pressure at a gradually decreases (OFF (1) in the figure). On the other hand, the hydraulic pressure of the second suction line 79b is
6 gradually rises by the action of 6 (in the figure, ON
(2)). Then, the time T1 'at which the OFF (1) and the ON (2) intersect
Thus, the power is shifted up from the first-speed power shift device 43 to the second-speed power shift device 44. That is, the period between times T1 and T1 'is the shift period of the multi-stage transmission 40.

Further, the controller 15 outputs a connection signal to the second proportional solenoid valve 86 and a disconnection signal to the electromagnetic clutch 27 at time T 1 based on the signal from the potentiometer 131.

FIG. 7B shows a change in the hydraulic pressure of the hydraulic oil line 84 of the lock-up mechanism hydraulic circuit with respect to time.
Note that the horizontal axes (time) in FIGS. 7A and 7B correspond to each other.

When the second electromagnetic proportional valve 86 connects the pressure oil line 82 and the hydraulic oil line 84, the oil pressure in the hydraulic oil line 84 increases, whereby the lock-up mechanism 50 connects the carrier 34 and the outer race 33 with each other. In the engaged state. The engagement state of the lock-up mechanism 50 is released at a time T1 ′ at which the gear shifting operation of the multi-speed transmission 40 is completed. That is, the pressure sensor 77a of the multi-stage transmission hydraulic circuit connected to the controller 15 detects that the hydraulic pressure in the hydraulic oil line 77 reaches a predetermined hydraulic pressure X sufficient to engage the second speed power shift device. When the controller 15 detects that the pressure sensor 77a has
At time T1 ', the second electromagnetic proportional valve 86 is operated to connect the hydraulic oil line 84 to the discharge line 87 (the position of the second electromagnetic proportional valve in FIG. 2). As a result, the hydraulic pressure of the hydraulic oil line 84 decreases, and the lock-up mechanism 50 is disengaged. Thus, the lock-up mechanism 50
Is engaged only during the period from time T1 to T1 ′, that is, during the shift period of the multi-speed transmission 40.

On the other hand, when the electromagnetic clutch 27 is disengaged at time T 1, the connection between the pump displacement control shaft 26 and the shifter 28 is released, so that the swash plate of the hydraulic pump 22 is free with respect to the shift lever 140. State.
Note that the electromagnetic clutch 27 is also reconnected at the time T1 ', similarly to the second electromagnetic proportional valve 86. That is, the swash plate of the hydraulic pump is in a free state with respect to the shift lever 140 only during a period from time T1 to time T1 ', that is, during the shift period of the multi-speed transmission 40.

Considering the speed vector of the planetary gear device 30 during the operation period of the multi-speed transmission 40, FIG.
It becomes as shown in. That is, during the shift period of the multi-speed transmission 40, the carrier 34 and the outer race 33 are integrated by the action of the lock-up mechanism 50 as described above.
That is, the outer race 33 rotates together with the carrier 34.

When two speed vectors of the sun gear, the carrier, and the outer ring are determined in the planetary gear device, the remaining one speed vector is determined by the other two speed vectors. Therefore, the multi-stage transmission 4
During the shift period of 0, the rotation speed vector of the sun gear 31 is equal to the rotation speed vector of the carrier 34 and the outer race 33.
(See FIG. 8).
(c)). Since the sun gear 31 is connected to the output of the HST 20, the output of the HST 20 is determined by determining the rotation speed vector of the sun gear 31.

Here, during the shift period, the swash plate of the hydraulic pump is in a free state. Accordingly, during the shift period, the swing angle of the swash plate is regulated by the output of the HST 20. That is, the swash plate is returned to the position where the HST output corresponding to the rotation output of the sun gear 31 determined by the carrier 34 and the outer ring 33 is maintained without changing the swing position of the shift lever 140. Become. In the present embodiment, the swash plate is returned to the position where the HST output rotates in the reverse direction (see “Swash plate swing region at T1 to T1 ′” in FIG. 3).

Thereafter, at time T1 ', the second electromagnetic proportional valve 86 connects the hydraulic oil line 84 to the discharge line 87 and the electromagnetic clutch 27 as described above. That is, at time T1 ', the lock-up mechanism 50 is disengaged and the swash plate of the hydraulic pump swings in conjunction with the swing of the shift lever 140. Therefore, the time T
In the period from 1 'to T2, the output of the HST 20 increases with the inclination of the shift lever 140, and the vehicle speed increases accordingly.

That is, as shown in FIG. 9, in the present embodiment, while the shift lever 140 is located in the F1 region (ie, while the multi-speed transmission is in the first speed), the shift lever 14
When the shift lever 140 reaches the boundary point between the F1 region and the F2 region (ie, the multi-speed transmission shifts from the first speed to the second speed) During the gear shift period), only the swash plate returns with the shift lever 140 in the same position. That is, the multi-stage transmission 40 is not shifted while the HST is in the maximum output state, and the output of the HST is automatically reduced when the multi-stage transmission is shifted.

In the traveling transmission according to the present embodiment thus configured, the following effects can be obtained in addition to the various effects described above.

That is, the power is branched from the main drive shaft 10 operatively connected to the drive source 100 to the HST 20, and the remaining power of the main drive shaft 10 is further transmitted to the planetary gear device 30.
, The output of the HST 20 is input to the sun gear 31 to transmit power from the outer race 33 to the multi-stage transmission 40. Only the carrier 34
Since the lock-up mechanism 50 that integrates the outer ring 33 with the outer ring 33 is provided, the rate of change in vehicle speed during shifting of the multi-stage transmission 40 can be suppressed. That is, the multi-stage transmission 40
Operating the HST 20 in a state where
Since the output of the HST 20 is automatically reduced when the multi-speed transmission 40 is shifted to the next speed, the vehicle speed is increased automatically. it can. Such a reduction in the rate of change of the vehicle speed at the time of shifting of the multi-stage transmission 40 effectively prevents failure of the multi-stage transmission and the like, and improves the riding comfort and operability of the vehicle.

Further, in the present embodiment, HST
In the traveling transmission including the transmission 20 and the multi-stage transmission 40, only a part of the power from the drive source is input to the HST 20, so that the HST 20 can be downsized.

That is, the total power from the driving source 100 is
In the conventional traveling transmission configured to transmit the power to the multi-stage transmission via the HST, the HST having a capacity corresponding to the maximum output of the driving source has to be used. On the other hand, in the present embodiment, HST20
Because only a part of the power of the drive source 100 is input to
The HST 20 can be reduced in size as compared with the related art.

Further, in the present embodiment, the HST
And a potentiometer 131 for detecting the swing angle of the shift lever 140 connected to the swash plate.
The multi-stage transmission 40 is configured to shift according to the swing angle of the HST and the HST and the multi-stage transmission can be operated with one operating lever. Therefore, the HST and the multi-stage transmission are independently operated. Operability can be improved as compared with the conventional traveling transmission.

In the present embodiment, the electromagnetic clutch 27 is provided, and the shift period of the multi-speed transmission 40 is HST.
The swash plate 20 and the shift lever 140 are configured not to interlock, but this is to improve the operability of the vehicle.

That is, when the swash plate and the speed change lever are configured to be constantly linked, the shift lever 140 is returned together with the swash plate when the multi-stage transmission 40 shifts. In this case, the driver tilts the shift lever 140 while the multi-speed transmission 40 is engaged with the first speed, and releases the shift lever 140 only during the shift period of the multi-speed transmission 40 to release the gear. The shift lever must be allowed to return.

On the other hand, if the swash plate is free with respect to the shift lever 140 during the shift period of the multi-stage transmission 40 as in the present embodiment, the driver can operate the multi-stage transmission. The shift lever 140 can be operated normally without worrying about the shift period of 40.

As described above, in order to improve the operability of the vehicle, it is preferable that the swash plate is free with respect to the shift lever 140 during the operation of the multi-stage transmission 40. If you want to reduce costs,
The swash plate and the shift lever may always be linked.

Further, in the present embodiment, as shown in FIGS. 1 and 5, the lock-up mechanism 50 is disposed immediately behind the planetary gear device 30, but the present invention is not limited to such an embodiment. Instead, various modes can be applied as long as the carrier 34 and the outer ring body 33 of the planetary gear device can be rotated synchronously during the shift period of the multi-speed transmission 40. For example, as shown in FIG. 10, a lock-up mechanism 50 ′ is disposed at the rear stage of the multi-stage transmission 40, and the main drive shaft 10 to which the carrier 34 is connected and the multi-stage transmission 40 to which the outer ring 33 is connected. And the drive shaft 41 may be configured to be rotated synchronously.

[0071]

According to the vehicle transmission of the present invention, there is provided a continuously variable transmission having a swash plate and a main drive shaft operatively connected to the drive source. A continuously variable transmission for branching and inputting power from the main drive shaft, a sun gear operatively connected to an output shaft of the continuously variable transmission, a carrier connected to the main drive shaft so as to be relatively non-rotatable, A planetary gear device having a planetary gear that meshes with a gear and revolves according to the rotation of the carrier, an outer ring body provided with an internal gear that meshes with the planetary gear, and a drive shaft operatively connected to the outer ring body A multi-stage transmission having a driven shaft disposed in parallel with the drive shaft and performing multi-stage transmission between the two shafts; and synchronously rotating the carrier and the outer race body only during a shift period of the multi-stage transmission. Lock-up mechanism and Since so provided, may be in conjunction with the shift operation of the mechanical transmission, automatically adjusts the inclination angle of the swash plate of the HST. Therefore, it is possible to smoothly change the vehicle speed at the time of shifting the multi-stage transmission.

Further, since a part of the power from the driving source is inputted to the continuously variable transmission, it is possible to effectively prevent the failure of the continuously variable transmission and to reduce the number of the continuously variable transmission. The capacity can be increased.

Further, if the swash plate is connected to traveling speed change operation means and the connection state is released only during the shift period of the multi-stage transmission, the swash plate can be connected regardless of the traveling speed change operation means. The tilt angle of the plate is automatically adjusted. Therefore, the operability of the vehicle can be improved.

Further, a swing angle detecting device for detecting a swing angle of the traveling speed change operating means is further provided. Based on a signal from the swing angle detecting device, a shift operation of the multi-stage transmission is performed and a lock-up is performed. If the mechanism is configured to be operated, it is possible to operate both the continuously variable transmission and the multi-stage transmission by operating only one traveling speed change operation means, and it is possible to further improve the operability.

[Brief description of the drawings]

FIG. 1 is a transmission path diagram of a vehicle to which a preferred embodiment of a traveling transmission according to the present invention is applied.

FIG. 2 is a hydraulic circuit diagram of a portion related to the traveling transmission shown in FIG.

FIG. 3 is a block diagram of a portion related to the traveling transmission shown in FIG. 1;

FIG. 4 is a cross-sectional view of the planetary gear set in the traveling transmission shown in FIG.

FIG. 5 is a longitudinal sectional view of the vicinity of a planetary gear unit, a lock-up mechanism, and a multi-stage transmission in the traveling transmission shown in FIG. 1;

FIG. 6 is a sectional view taken along line AA in FIG. 3;

FIG. 7 (a) is a waveform diagram showing a change in hydraulic pressure of a hydraulic oil line in a hydraulic circuit for a multi-stage transmission with respect to time. FIG. 7B is a waveform diagram illustrating a change in hydraulic pressure of the hydraulic oil line in the lock-up mechanism hydraulic circuit with respect to time.

FIG. 8 is a velocity vector diagram of the planetary gear device. 8 (a) and 8 (b) show that the multi-stage transmission is the first
HST low output and H
The velocity vector diagram at the time of ST large output is shown. Fig. 8 (c)
Shows a speed vector diagram of the multi-speed transmission during a shift period.

FIG. 9 is a waveform diagram showing a relationship between a vehicle speed and an angle of a swash plate of the hydraulic pump.

FIG. 10 is a transmission path diagram of a vehicle to which another embodiment of the traveling transmission according to the present invention is applied.

[Explanation of symbols]

 Reference Signs List 1 traveling transmission 10 main drive shaft 20 HST 21 input shaft 22 hydraulic pump 23 output shaft 24 hydraulic motor 25 swash plate 30 planetary gear device 31 sun gear 32 planetary gear 33 outer ring body 34 carrier 40 multi-stage transmission device 41 drive shaft 42 driven shaft 43 power shift device 50 lock-up mechanism 100 drive source 110 drive wheel

Continued on front page F term (reference) 3D039 AA02 AA04 AB11 AC24 AC26 AC32 AC37 AC39 AC40 AC54 AC74 AC77 AC88 AD06 AD23 AD43 AD44 AD53 3D042 AA01 AA05 AA10 BA02 BA07 BA08 BA14 BA19 BA20 BC13 BC17 BD04 BD05 BD06 BD08 BD09

Claims (3)

[Claims] 1. A traveling transmission for a vehicle interposed in a transmission path from a drive source to a drive wheel, wherein at least one of a main drive shaft operatively connected to the drive source is of a variable displacement type. Continuously variable transmission having a hydraulic pump and a hydraulic motor, wherein the power from the drive source is branched and input from the main drive shaft, and the output is continuously variable by operating a swash plate. A continuously variable transmission, a sun gear operatively connected to the output shaft of the continuously variable transmission, a carrier non-rotatably connected to the main drive shaft, meshing with the sun gear, and according to the rotation of the carrier. A planetary gear device having a revolving planetary gear, and an outer ring provided with an internal gear meshing with the planetary gear, a drive shaft operatively connected to the outer ring, and disposed in parallel with the drive shaft. Servant A multi-stage transmission having a shaft and performing multi-stage transmission between the two shafts; and a lock-up mechanism for synchronously rotating the carrier and the outer race body only during a shift period of the multi-stage transmission. The transmission for traveling of the vehicle. 2. The swash plate according to claim 1, wherein the swash plate is connected to traveling speed change operation means, and the connection state is released only during a shift period of the multi-speed transmission. Transmission for running vehicles. 3. The apparatus according to claim 1, further comprising a swing angle detecting device for detecting a swing angle of the operation shift operating means, wherein a gear shift operation of the multi-stage transmission is performed and a lock-up is performed based on a signal from the swing angle detecting device. The transmission according to claim 2, wherein the mechanism is configured to operate.