JP2000351332A - Transmission for running of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reasonably change over from a low speed running mode to high speed running mode during running of a vehicle in a transmission for running provided with an HST. SOLUTION: This transmission for running of a vehicle is provided with a main drive shaft 10 connected operatively to a drive source 100, an HST 20 into which power from the drive source is inputted, a drive shaft 11 in which power from the drive source is inputted, a planetary gear device 30 having a sun gear 31 supported on an output shaft of the HST so as not to rotate relatively, and a first clutch device 210 and a second clutch device 220 engaging and disconnecting a carrier 34 of the planetary gear device and an output shaft 23 and the carrier 34 and the drive shaft 11, respectively.

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 traveling transmission provided with a continuously variable transmission (HST).

[0002]

2. Description of the Related Art A traveling transmission having an HST capable of continuously changing the output by operating a swash plate is known as disclosed in, for example, Japanese Patent Application Laid-Open No. 54-13131. The traveling transmission described in the above publication is provided with a multi-stage transmission on the rear side of the HST, and thereby can perform both low-speed traveling such as when performing agricultural work and high-speed traveling such as when traveling on a general road. .

[0003] In other words, in consideration of the fact that it is difficult to cope with both low-speed traveling and high-speed traveling with the HST alone, the conventional traveling transmission is provided with a multi-stage transmission at the subsequent stage of the HST. When performing low-speed traveling, the multi-stage transmission is engaged with the low-speed gear and H
By operating the ST, it is possible to adjust the speed in the low-speed range. On the other hand, when performing high-speed running, the speed in the high-speed range is controlled by operating the HST with the multi-stage transmission engaged with the high-speed range. Adjustment is possible.

[0004] However, the conventional traveling transmission does not assume switching between low-speed traveling and high-speed traveling during vehicle traveling. That is, the conventional transmission for traveling, (1) when low-speed traveling such as during agricultural work is required, after putting the multi-stage transmission in the low-speed stage in advance, operating the HST to travel the vehicle, 2) When high-speed traveling is required, such as when driving on public roads, the vehicle is temporarily stopped, then the multi-stage transmission is put into the high-speed stage, and the HST is operated to drive the vehicle. Met.

Therefore, 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.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and is a traveling transmission having an HST. It is an object of the present invention to provide a traveling transmission that can easily switch to the transmission mode and that can continuously change the speed in each traveling mode.

[0007]

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 power from the drive source is input from the main drive shaft, and a swash plate is provided. A continuously variable transmission that outputs power that is continuously variable in response to an operation from an output shaft that extends to a rear side of the transmission path, and that is disposed substantially parallel to the output shaft at a rear side of the continuously variable transmission; A drive shaft to which power from a drive source is input via a main drive shaft, a sun gear supported non-rotatably on the output shaft, a planetary gear that meshes with the sun gear and revolves around the sun gear, A key that rotates according to the revolution of the planetary gear A planetary gear device having a rear, and the outer race of an internal gear is provided to the planetary gear meshes,
A traveling transmission including a first clutch device that engages / disengages the carrier and the output shaft, and a second clutch device that engages / disengages the carrier and the drive shaft.

Preferably, the vehicle further includes a traveling speed change operating means connected to the swash plate, and a swing angle detecting device for detecting a swing angle of the traveling speed changing operation means. A low-speed running mode in which the first clutch device is engaged and the second clutch device is disengaged, and the first clutch device is disengaged and the second clutch device is disengaged.
It can be configured to switch between a high-speed running mode in which the clutch device is engaged.

[0009] Further, by swinging the traveling speed change operation means in one direction, it is possible to switch from the low speed traveling mode to the high speed traveling mode.

[0010] Preferably, the first clutch device is engaged in a normal state, and is disengaged based on a signal from the swing angle detecting device.

Preferably, an engagement device for forcibly engaging the second clutch device can be provided.

[0012] Preferably, the vehicle may further include a multi-stage transmission device which is arranged at a subsequent stage of the transmission path of the planetary gear device and is capable of changing the power output from the outer race of the planetary gear device in multiple stages.

The multi-stage transmission has a high-speed shift stage for driving the vehicle at a high speed and a low-speed shift stage for driving the vehicle at a low speed. When the vehicle runs under a high load, the low-speed shift stage is engaged. In addition, when the vehicle travels under a low load condition, the high speed gear can be configured to be engaged.

[0014]

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. FIG. 2 is a hydraulic circuit diagram of a portion related to the traveling transmission 1.

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 drive shaft 10 operatively connected to the driving source 100. A continuously variable transmission 20 that receives power from the drive source 100 via the main drive shaft 10 and outputs the power from an output shaft 23 that extends rearward; A drive shaft 11 arranged substantially parallel to the shaft 23 and receiving power from a drive source 100 via the main drive shaft 10
A planetary gear device 30 supported on the output shaft 23;
A first clutch device 210 for engaging / disconnecting the carrier 34 and the output shaft 23 of the planetary gear device; a second clutch device 220 for engaging / disconnecting the carrier 34 and the drive shaft 11; And a multi-stage transmission 50 arranged on the rear side of the gear device 30. FIG.
, 120 is a PTO shaft serving as a power take-out shaft of a towing work machine such as a rotary tilling device, and 160 is a power take-out shaft to a rear wheel.

The HST 20 includes a hydraulic pump 2 for directly inputting power from a drive source 100 from the main drive shaft 10.
2 and a hydraulic motor 24 having an output shaft 23, and at least one of the hydraulic pump 22 and the hydraulic motor 24 is a variable displacement type in which the volume can be varied by a swash plate 25. In the present embodiment, the hydraulic pump 22 is of a variable displacement type. The main drive shaft 10 has a rear end portion extending through the hydraulic pump to a rear side of the transmission path. On the other hand, the output shaft 23 of the HST 20 extends to the downstream side of the transmission path as described above. The output shaft 23 is
As shown in FIG. 1, a plurality of shafts may be connected to each other so as not to rotate relative to each other about an axis, or an integrated shaft may be used.

As shown in FIG. 1, the drive shaft 11 is disposed coaxially with the main drive shaft 10 and is
Are connected to each other so that they cannot rotate relative to each other about the axis, so that power from the drive source 100 is input via the main drive shaft 10. The rear end of the drive shaft 11
The drive shaft 11 is connected to a PTO power transmission path.
Power is transmitted to the PTO shaft 120 via the.

FIG. 3 is a cross-sectional view of the planetary gear device 30. As shown in FIG. As shown in FIGS. 1 and 3, the planetary gear device 30 includes a sun gear 31 that is supported by the output shaft 23 so as not to rotate relatively, and a planet that meshes with the sun gear 31 and revolves around the sun gear. A gear 32, a carrier 34 that rotates according to the revolution of the planetary gear 32, and an outer race 33 provided with an internal gear that meshes with the planetary gear 32 are provided. The first driven shaft 13 is connected to the outer race 33 so that the first driven shaft 13 cannot rotate relatively around the axis. The first driven shaft 13
A multi-stage transmission mechanism 50 can be provided on the rear stage side.

The arrows in FIG. 3 indicate the rotation directions of the outer race 33, the carrier 34, and the sun gear 31 when the main drive shaft 10 is rotated clockwise in the configuration shown in FIG. The direction of rotation of each component of these planetary gear devices can be set as appropriate according to the configuration of the power transmission mechanism from the drive source to the planetary gear device.

As shown in FIGS. 1 and 2, the first clutch device 210 is supported on the output shaft 23 so as to be relatively non-rotatable, and is supported on the output shaft 23 so as to be relatively rotatable. And a first driven side member 210b connected to the carrier 34 of the planetary gear unit so as not to rotate relatively.
And The first drive side member 210a and the first driven side member 210b are provided with clutch plates that can be engaged with each other.

Further, the first clutch device 210 includes:
The first pushing member 210c supported movably in the axial direction by the output shaft 23 and the first pushing member so that the clutch plates of the first driving member 210a and the first driven member 210b are engaged with each other. A first urging member 210d for urging the moving member 210c. A first engagement side suction line 79a and a first disconnection side suction line 79a 'described later are connected to the engagement side oil chamber 211 and the cutting side oil chamber 212 defined by the first pushing member 210c, respectively. (See FIG. 2).

The first clutch device 210 has the above-described configuration, and when the pressurized oil is not supplied, the pressing member 2
10c and the first driving side member 2 by the urging member 210d.
10a is engaged with the first driven side member 210b, and when pressure oil is supplied from the first discharge side suction line 79a 'to the discharge side oil chamber 212, the first drive side is actuated by the action of the pressure oil. The member 210a and the first driven side member 210b are cut off. The first engagement side suction line 79
The reason why the pressurized oil can be supplied to the engagement side oil chamber 211 via a is to use the action of the pressurized oil in addition to the action of the pushing member 210c and the urging member 210d. This is for more securely engaging the side member 210a and the first driven side member 210b.

As shown in FIGS. 1 and 2, the second clutch device 220 includes a second drive-side member 220a rotatably supported on the output shaft 23 and operatively connected to the drive shaft 11. A second driven member 220b rotatably supported by the output shaft 23 and non-rotatably connected to the carrier 34 of the planetary gear set. The second
The driving side member 220a and the second driven side member 220b include:
Clutch plates are provided that can be engaged with each other.

Further, the second clutch device 220 includes:
The output shaft 23 includes a second pushing member 220c supported movably in the axial direction. The second pushing member 220c is
The clutch plates of the second drive-side member 220a and the second driven-side member 220b are engaged with each other under the action of pressure oil supplied from a second suction line 79b described later. The second clutch device 220 includes a second pushing member 2.
20c to the second drive side member 220a and the second driven side member 2
Urging member 220d for separating from each clutch plate 20b
Can be provided. By providing the urging member 220d, the clutch plates of the second drive-side member 220a and the second driven-side member 220b can be reliably disconnected when pressure oil is not supplied to the second clutch device 220. .

Here, the hydraulic circuit 70 of the first and second clutch devices will be mainly described with reference to FIG. The hydraulic circuit 70 includes, as shown in FIG.
A hydraulic pump 71 for the first and second clutch devices that sucks oil from 0 and discharges pressure oil, and a pressure oil line 72 for the clutch device through which the pressure oil discharged from the hydraulic pump 71 flows. The pressure oil line 72 is branched to a lubrication oil line 73 at a stage subsequent to the delay relief valve 75a for setting the operating oil pressure of the pressure oil line. Lubricating oil line 73
Is for supplying lubricating oil to each of the clutch devices 210 and 220. 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 rear end of the pressure oil line 72 is connected to an emergency switching valve 74. A first hydraulic oil line 76a and a second hydraulic oil line 76b are connected to the downstream side of the emergency switching valve 74, and a discharge line 91a is further connected to the upstream side.

The emergency switching valve 74 moves the hydraulic oil line 72 to the first position based on the operation of the emergency lever 74b.
A second hydraulic oil line 76 connected to the hydraulic oil line 76a;
A normal position (position shown in FIG. 2) where b is connected to the discharge line 91a and a second clutch forced engagement position where the pressure oil line 72 is connected to the first hydraulic oil line 76a and the second hydraulic oil line 76b. It has become. The position control of the switching valve may be such that, instead of the emergency lever 74b, the switching valve is normally located at the normal position, and takes a second clutch engagement position when a signal is received. The signal may be input via a controller described later, or may be input directly.

The rear end of the first hydraulic oil line 76a is connected to a range switching valve 78. The range switching valve 7
8, the first engagement side suction line 79a and the first
Cutting-side suction line 79a 'and second suction line 7
The discharge line 91b is connected to the upstream side of the range switching valve 78.

The first engagement side suction line 79a and the first
As described above, the rear end of the disconnection-side suction line 79a 'communicates with the engagement-side oil chamber 211 and the disconnection-side oil chamber 212 of the first clutch device, and the rear end of the second suction line 79b is the second end. It is connected to the clutch device.

The second hydraulic oil line 76b is connected to the second suction line 79b via a check valve 77. The check valve 77 prevents pressure oil from flowing from the second hydraulic oil line 76b to the second suction line 79b, but does not flow in the opposite direction.

The range switching valve 78 connects the first hydraulic oil line 76a to the first engagement side suction line 79a and the first disconnection side suction line 79a 'based on a signal from the controller 15 described later. A first clutch engagement position (a position shown in FIG. 2) for connecting to the discharge line 91b,
A first clutch disengagement and second clutch engagement position for connecting the hydraulic oil line 76a to the first disconnection side suction line 79a 'and the second suction line 79b and connecting the first engagement side suction line 79a to the discharge line 91b; To take.

The multi-stage transmission 50 includes a first shaft 51 and a second shaft 52 arranged substantially in parallel, and a transmission mechanism 53 for transmitting power by changing the power between the two shafts in multiple stages. In the present embodiment, as shown in FIG. 1, as the first axis and the second axis, respectively, a cylindrical shaft 51 externally rotatably mounted on the drive shaft 11 and a shaft substantially parallel to the cylindrical shaft. The second driven shaft 52 is used.

In this embodiment, the speed change mechanism 5
Reference numeral 3 denotes a two-stage transmission mechanism capable of switching between a low speed stage and a high speed stage. That is, the transmission mechanism 53 includes a high-speed transmission mechanism 54 and a low-speed transmission mechanism 55 capable of transmitting power between the first shaft 51 and the second shaft 52 at a high speed ratio and a low speed ratio, respectively. And a clutch mechanism 56 for switching between the two transmission mechanisms.

The high-speed transmission mechanism 54 includes the cylindrical shaft 51
High-speed first transmission member 54a supported so as to be relatively non-rotatable
And a high-speed second transmission member 54b rotatably supported by the second driven shaft 52 and operatively connected to the high-speed first transmission member. The low-speed step transmission mechanism 55 includes a low-speed first transmission member 55a supported by the cylinder shaft 51 so as not to rotate relatively, and a low-rotation first transmission member 55a supported by the second driven shaft 52 so as to be relatively rotatable. A low-speed second transmission member 55b operatively connected to the transmission member.

The clutch mechanism 56 is a high-speed clutch device 57 for engaging / disconnecting the high-speed second transmission member 54b and the second driven shaft 52, and selectively operates with the high-speed clutch device. , The low-speed second transmission member 55b
And a low speed clutch device 58 that engages / disengages the second driven shaft 52.

In the present embodiment, the high speed clutch device 57 is a hydraulic clutch, and the low speed clutch device 58 is a mechanical pawl clutch. That is, in the present embodiment, as shown in FIGS. 1 and 2, the high-speed clutch device 57 is supported by the second driven shaft 52 so as to be relatively rotatable and non-slidable in the axial direction. Drive-side friction plate 57a connected to second transmission member 54b
A driven-side friction plate 57b supported by the second driven shaft 52 so as to be relatively non-rotatable and slidable in the axial direction; and the driven-side friction plate 57b is
a, and an urging member 57d for urging the pressing member 57c in a direction to separate the pressing member 57c from the driven friction plate 57b. The low-speed clutch device 58 is supported by the second driven shaft 52 and the driving-side member 58a connected to the low-speed second transmission member 55b so as to be relatively non-rotatable and slidable in the axial direction. A shifter 58b for engaging / disconnecting the member 58a is provided, and the shifter 58b and the pushing member 57c are connected to each other.

Here, the hydraulic circuit 80 for the low speed clutch device will be described with reference to FIG. As shown in FIG. 2, the hydraulic circuit 80 includes a hydraulic pump 81 for a low-speed clutch device that sucks oil from an oil tank 90 and discharges pressure oil, and a high-speed hydraulic pump 81 through which the pressure oil discharged from the hydraulic pump 81 flows. A pressure oil line 82 for the step clutch device, a high speed / low speed switching valve 83 connected to the rear end of the pressure oil line 82, and a hydraulic oil line 84 connecting the switching valve and the high speed clutch device. I have. Further, a discharge line 86 is provided at a front end side of the switching valve 83. The pressure oil line 82 has a lubricating oil line 88 on the downstream side of a relief valve 85a for setting the oil pressure of the pressure oil line 82.
Has been branched to. The lubricating oil line 88 is for supplying lubricating oil to the clutch mechanism. In the figure, reference numeral 85b denotes a relief valve for setting the lubricating oil pressure of the lubricating oil line 88.

The switching valve 83 is connected to a high-speed clutch engaging position and a low-speed gear for connecting the hydraulic oil line 84 to the pressure oil line 82 and the discharge line 86 based on an external operation (including a signal). The clutch engagement position is set.

When the switching valve 83 is in the high-speed clutch engagement position, the pressing member 57c of the high-speed clutch device is pushed leftward in FIG. 2 by the action of pressure oil. As a result, the pushing member 57c moves the driven friction plate 57b against the driving friction plate 57b against the urging force of the urging member 57d.
a, and the high-speed clutch device 57 is engaged. On the other hand, the shifter 58b of the low-speed clutch device connected to the pushing member 57c is
7c, it moves to the left in FIG. That is,
The shifter 58b is separated from the drive side member 58a, and the low speed clutch device 58 is in a disconnected state.

Conversely, when the switching valve 83 is in the low-speed clutch position, no pressure oil is supplied to the high-speed clutch device 57. Accordingly, the urging force of the urging member 57d causes the pushing member 57c to move in a direction away from the driven friction plate 57b (to the right in FIG. 2). Therefore, the high speed clutch device 57 is in the disconnected state. on the other hand,
The shifter 58b moves rightward in FIG. 2 according to the movement of the pushing member 57c, and engages with the driving member 58a. Accordingly, the low speed clutch device 58
Is in the engaged state.

As described above, the clutch mechanism 56 selectively engages either the high speed clutch device 57 or the low speed clutch device 58.

Next, the position control of the switching valve 83 will be described. As shown in FIG. 1, among hydraulic lines connecting the hydraulic pump 22 and the hydraulic motor 24 of the HST 20,
A pressure sensor 87 is connected to the hydraulic line 20a, which becomes a high pressure during forward movement.
And the controller 15 inputs a hydraulic signal of the high-pressure line 20a during forward movement to the controller 15.

When the wheel does not receive much resistance during traveling, such as when traveling on a road, the HST output shaft 23 is operatively connected to the wheel so that a large load is not applied to the HST output shaft 23. Therefore, the hydraulic pressure of the high-pressure line 20a during forward travel is low. On the other hand, when resistance is applied to the wheels during traveling, such as during work, a large load is applied to the HST output shaft 23. Therefore, the hydraulic pressure of the high-pressure line 20a at the time of forward movement becomes high.

As described above, the hydraulic pressure of the high-pressure line 20a during forward movement fluctuates according to the running state of the vehicle. Therefore, the controller 15 detects the hydraulic pressure of the high-pressure line 20a during forward movement, and if the hydraulic pressure is equal to or less than the set value, the high / low speed switching valve 83 is positioned at the high-speed side clutch engagement position. If the high-speed / low-speed switching valve 83 is positioned at the low-speed side clutch engagement position, the high-speed clutch device 57 is automatically engaged when high-speed running is appropriate, such as when driving on a road. When low-speed running is appropriate, such as during work, the low-speed clutch device 58 can be automatically engaged.

In this embodiment, the engagement / disengagement of the high-speed clutch device 57 and the low-speed clutch device 58 is automatically performed based on the hydraulic pressure of the forward high pressure line 20a as described above. Although control is performed, the present invention is not limited to such a form, and various forms can be applied. For example, when a working machine is mounted on a vehicle, it is detected whether or not the working machine is at a working position, and a high-speed clutch device and a low-speed clutch device are switched based on the detection signal. You can also. Further, it is also possible to provide a strain sensor at a connection portion of the work machine, and to engage the low-speed clutch device when it can be determined that work is being performed based on a signal from the strain sensor.
Further, the engagement / disconnection of the high-speed clutch device 57 and the low-speed clutch device 58 may be switched by a manual operation.

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. 2, Pfmax and Prmax
Indicates swinging ends of the swash plate at the time of the maximum output of the HST in the vehicle forward direction and at the time of the maximum output of the vehicle in the reverse direction, respectively. That is, the swash plate can swing between Pfmax and Prmax. N indicates the neutral position of the swash plate.

A swash plate (not shown in FIG. 2) of the hydraulic pump 22 is supported by a pump displacement control shaft 26,
It swings with the rotation of the shaft. The axis 2
6 is provided with a swash plate side potentiometer 29 connected to the controller 15. Then, based on a signal from the potentiometer 29, the controller 15 can detect the rotation angle of the shaft 26. Further, the shaft 26 supports the base end of the shifter 28 so as not to rotate relatively.

The outer end of the shifter is a cylinder 3
09 is connected to a piston rod inserted movably in the axial direction. That is, the outer end of the shifter swings in accordance with the movement of the piston rod 310 in the axial direction, whereby the pump displacement control shaft 26 rotates and the swash plate swings.

The cylinder 309 is separated into a forward oil chamber 309a and a reverse oil chamber 309b by a large diameter portion 310a of a piston rod. The forward oil chamber 309a and the reverse oil chamber 309b respectively have
The rear ends of the forward line 306 and the reverse line 307 are connected.

The forward ends of the forward line 306 and the reverse line 307 are connected to the downstream side of the three-position switching valve 305. On the other hand, a pressure oil line 303 and a discharge line 308 are connected to the upstream side of the three-position switching valve 305. That is, the three-position switching valve 305 closes the forward position line 306 and the reverse position line 307 by connecting the forward position line 306 to the pressure oil line 303 and connecting the reverse position line 307 to the discharge line 308. N position and R connecting the forward line 306 to the discharge line 308 and connecting the reverse line 307 to the pressure oil line 303
Position. Note that in FIG.
Reference numeral denotes an oil tank, reference numeral 302 denotes a hydraulic pump, and reference numeral 304 denotes a relief valve for setting the operating oil pressure of the pressure oil line.

On the other hand, the swash plate is connected to traveling speed change operation means via an appropriate power transmission mechanism. In the present embodiment, a shift lever 140 is used as the traveling shift operation means. The shift lever 140 is supported by the shift lever support shaft 141 so as not to rotate relatively. The shift lever support shaft 141 has a controller 1
5 is provided with a shift lever potentiometer 131 connected to the transmission lever 5. That is, the controller 15 detects the swing angle of the shift lever based on the signal from the potentiometer 131.

Hereinafter, (i) when the shift lever 140 is swung within the range 1 while the emergency switching valve 74 is located at the normal position (hereinafter referred to as case (i)), (ii) emergency The switching from the range 1 to the range 2 with the switching valve 74 in the normal position, and swinging in the range 2 (hereinafter referred to as case (ii)), and (iii) the emergency switching valve 74 The transmission mechanism of the traveling transmission 1 will be described by taking as an example the case in which is located at the second clutch forced engagement position (hereinafter referred to as case (iii)).

Case (i) On the basis of the signal from the shift lever potentiometer 131, the controller 15 outputs a signal for causing the range switching valve 78 to take the first clutch engagement position. When the emergency switching valve 74 is at the normal position, as described above, the pressure oil line 72 is connected to the first hydraulic oil line 76a. Therefore, when the range switching valve is located at the first clutch engagement position, pressure oil is supplied to the engagement side oil chamber 211 via the first engagement side suction line 79a, and the disengagement side oil chamber 212
Is discharged via the first cut-side suction line 79a 'and the discharge line 91b. Thus, the engagement state of the first clutch 210 is maintained by the action of the pressure oil in addition to the action of the pushing member 210c and the urging member.

When the first clutch device 210 is engaged, the carrier 34 of the planetary gear device 30 and the output shaft 23 rotate integrally. That is, the first clutch device 210 engages / disengages the carrier 34 and the output shaft 23.

Since the sun gear 31 is supported by the output shaft 23 so as to be relatively non-rotatable, in the case (i), the input, control and output of the planetary gear device 30 are determined by the sun gear 31 and the carrier 34. Further, the outer ring body 33 is output by the control. This state is a low-speed running mode in which the vehicle runs at a low speed.

FIG. 5 shows a rotational speed vector (angular speed vector) diagram of the planetary gear device 30 in the case (i).
FIGS. 5 (a) and 5 (b) show the case of case (i), respectively.
FIG. 9 is a rotation speed vector diagram when the output of ST20 is changed in one direction. That is, FIG. 5A shows a case where the HST is output slightly in the counterclockwise direction (hereinafter, referred to as the positive direction).
FIG. 5B is a rotation vector diagram when the HST is output in the maximum direction in the forward direction.

As described above, in case (i), H is input to the sun gear 31 and the carrier 34 and used as control.
The ST output is input, and the output is obtained from the outer race 33. Therefore, the rotation speed of the outer race 33 changes in proportion to the rotation speed of the sun gear 31, that is, the HST output (see FIG. 5). This state is a low-speed running mode in which the vehicle runs at a low speed.

On the other hand, the controller 15 outputs the following signals to the three-position switching valve 305.

When the shift lever 140 is in the neutral position, the controller 15 controls the shift lever potentiometer 13
1 to detect that shift lever 140 is at such a position. In response, the controller 15 outputs a signal for causing the three-position switching valve 305 to assume the N position. When the three-position switching valve 305 is in the N position, no pressure oil acts on the cylinder 309, so that the swash plate is kept at the neutral position. Therefore, the output shaft 23 of the HST does not rotate.

As described above, when the shift lever 140 is within the range 1, the outer race rotates in proportion to the HST output. Therefore, when the output shaft 23 of the HST does not rotate, that is, when the shift lever is in the neutral position, the vehicle remains stopped. FIG. 4 shows the relationship between the swash plate angle and the vehicle speed. 4A and 4B show the swash plate angle and the vehicle speed when the low speed clutch device 58 of the multi-stage transmission 50 is engaged and when the high speed clutch device 57 is engaged, respectively. Shows the relationship.

When the shift lever 140 is swung in one direction (counterclockwise in FIG. 2) for moving the vehicle forward from the neutral position, the controller 15 controls the shift lever potentiometer 1
Based on the signal from 31, the swing of shift lever 140 is detected. Then, in response to this, the controller 15 outputs a signal for causing the three-position switching valve 305 to take the F position. When the three-position switching valve 305 takes the F position, the pressure oil line 303 and the forward side line 306
And the discharge line 307 and the reverse side line 307
Communicates with Thereby, the pressure oil flows into the forward oil chamber 309a of the cylinder 309, and the piston rod 310 moves rightward in FIG. Therefore, the shifter 28
Swings in the Pfmax direction, and the swash plate rotates the HST in the forward direction (counterclockwise in the downstream direction of the transmission path,
Swings in the positive direction).

On the other hand, a signal relating to the swing angle of the swash plate is fed back to the controller 15 from the swash plate potentiometer 29. The controller 15 controls the position of the three-position switching valve based on signals from both the shift lever potentiometer and the swash plate potentiometer so that the swing angle of the swash plate is linked to the swing angle of the shift lever. I do. That is, the controller 15 controls the two potentiometers 13
The three-position switching valve 305 is appropriately moved between the F position and the N position based on the signals 1, 29. In this way,
An HST output corresponding to the swing angle of the shift lever 140 is obtained.

As described above, in case (i), since the HST output as input and control is input to the sun gear 31 and the first carrier 34 and the output is obtained from the outer race, the first sun gear 31 As the rotational speed in the forward direction (counterclockwise direction) of the outer ring 33 increases, the rotational speed in the forward direction of the outer race 33 increases (see FIG. 5). Therefore, as the output of the HST in the forward direction increases, that is, as the shift lever inclines in the one direction, the rotation speed of the outer ring body 33 in the forward direction, that is, the rotation speed of the first driven shaft 13 in the forward direction, increases. Faster,
The vehicle speed in the forward direction increases (see the rightward portion of range 1 in FIG. 4).

When the shift lever 140 is swung from the neutral position in the other direction for moving the vehicle backward (clockwise direction in FIG. 2). In this case, the rotation direction of each component of the planetary gear device 30 is negative. Except for the direction (clockwise), this is the same as the case where the shift lever 140 is inclined in the one direction.
That is, as the shift lever is tilted in the other direction,
The vehicle speed in the reverse direction increases (see the leftward portion of range 1 in FIG. 4).

Case (ii) Next, the case where the shift lever 140 shifts from the range 1 to the range 2, that is, the case where the shift lever reaches the point a1 in FIG. 2 will be described. When the controller 15 detects that the shift lever 140 has reached the point a1 based on a signal from the potentiometer 131, the controller 15 responds to this by informing the range switching valve 78
A first clutch disconnection and a second clutch that connect the first engagement side suction line 79a to the first disconnection side suction line 79a 'and the second suction line 79b and connect the first engagement side suction line 79a to the discharge line 91b.
Let the clutch engage position.

Accordingly, pressure oil is supplied to the second suction line 79b and the first cutting side suction line 79a ', and
The engagement side suction line 79b is connected to the discharge line 91b. Accordingly, the second clutch device 220 is engaged by the action of the pressure oil supplied through the second suction line 79b and the first disconnection side suction line 79a '.
On the other hand, in the first clutch device, the engagement side oil chamber 211
Of the first engagement side suction line 79a and the discharge line 9
1b, and the pressure oil is supplied to the cutting-side oil chamber 212 via a first cutting-side suction line. Therefore, the first clutch device is brought into the disconnected state.

When the range switching valve 78 is moved to the first clutch device engagement position from the second clutch device engagement state, the pressure oil in the second clutch device 220 is supplied to the second suction line 79b and the check valve. 77, second hydraulic oil line 76
b, discharged via the emergency switching valve 74 and the discharge line 91a. Therefore, the second clutch device 220 is reliably brought into the disconnected state.

Thus, in case (ii), the first
The clutch device 210 is disconnected, and the second clutch device 220 is engaged. When the second clutch device 220 is engaged, the power of the drive shaft 11 is input to the carrier 34 via an appropriate power transmission mechanism. That is, the second clutch device 220 engages / disengages the carrier 34 with the drive shaft 11.

When the first clutch device 210 is disconnected and the
When the clutch device 220 is engaged, the power of the drive shaft 11 is input to the carrier 34 of the planetary gear device, and the HST output as a control input is input to the sun gear 31. When only the second clutch device 220 is engaged,
The traveling transmission 1 is in the high-speed traveling mode.

FIG. 6 shows a rotational speed vector (angular speed vector) diagram of the planetary gear device 30 in the case (ii).
FIGS. 6 (a) to 6 (c) show HS (HS) in case (ii), respectively.
FIG. 9 is a rotation vector diagram when the output of T is changed from a positive direction to a negative direction.

As described above, in case (ii), the HST output as the control input is input to the sun gear 31, the constant power from the drive shaft 11 is input to the carrier 34, and the output is obtained from the outer wheel body. I have. Therefore, as shown in FIG.
In response to the high-speed rotation of the sun gear in the negative direction, the rotation speed of the outer race in the positive direction increases (see FIG. 5). That is, the case
In (ii), as shown in FIG. 7, if the swash plate is swung so as to increase the HST output in the negative direction, the forward speed of the vehicle increases accordingly. That is, in case (ii), in inverse proportion to the HST output (the swing angle of the swash plate),
The vehicle speed changes.

Here, the reason why the case (ii) is in the high-speed running mode will be described. It is assumed that the range switching valve 78 is operated to engage the second clutch 220 in the HST maximum output state in case (i). Case (i) and case (i
In any of i), since the HST output is input to the sun gear 31, the rotation direction and the rotation speed of the sun gear 31 are the same even when the range switching valve 78 is switched.

On the other hand, in case (ii), carrier 3
4 receives a constant power from the drive shaft 11, the rotation speed of the carrier 34 (the revolution speed of the planetary gear 32) is
In the case (i) of the HST maximum output state (the state of FIG. 5 (b)), the drive shaft 11 and the carrier 34
If the reduction ratio of the transmission gear train leading to the range is set, the rotation speed and the rotation direction of the outer race 33 at the time of switching of the range switching valve 78 become equal to the state of FIG. 5B in the case (i). The rotation speed and the rotation direction of the carrier 34 can be set by the ratio of the number of teeth of the power transmission member from the drive shaft 11 to the carrier 34.

As described above, at the time of switching between the case (i) and the case (ii), the sun gear 31 and the carrier 34
The rotation speed and the rotation direction of the outer race 33 are set so as not to change. In case (ii), when the HST output is changed in the negative direction from this state, the outer race 33 further rotates in the positive direction at a higher speed (see FIGS. 6A to 6C). Therefore, the case (ii) is in the high-speed running mode in which the outer race 33 rotates at a higher speed than in the low-speed running mode of the case (i).

As described above, in case (ii), HST
When the swash plate is swung to change the output in the negative direction,
In response, the outer race 33 rotates in the forward direction at a higher speed than in the case (i), whereby the first driven shaft 13 rotates in the forward direction.

On the other hand, the controller 15 outputs a signal for setting the R position to the three-position switching valve 305. When the three-position switching valve 305 assumes the R position, the pressure oil line 303 and the backward line 307 communicate with each other, and the discharge line 307 and the forward line 306 communicate with each other. Accordingly, the pressure oil flows into the backward oil chamber 309b of the cylinder 309, and the piston rod 310 moves leftward in FIG. Therefore, the shifter 28 swings in the Prmax direction, and the swash plate swings in the direction for negatively rotating the HST.

Then, based on the feedback signal from the swash plate potentiometer 29 and the signal from the shift lever potentiometer 131, the controller 15 moves the three-position switching valve 305 appropriately between the R position and the N position. . That is, in range 2, the swash plate is swung so as to change the HST output in the negative direction as the shift lever is tilted in the one direction.

As described above, when the shift lever 140 is in the range 2
, The HST output changes in the negative direction according to the inclination of the shift lever in the one direction, so that the sun gear rotates from the positive direction to the negative direction according to the inclination of the shift lever in the one direction.

Accordingly, when the speed change lever is located in the range 2, the outer race 33 rotates in the forward direction at a higher speed than in the range 1 in accordance with the inclination of the speed change lever in the one direction. As a result, the first driven shaft 13 rotates in the forward direction at an increased speed, and the forward speed of the vehicle increases (see the range 2 portion in FIG. 4).

Case (iii) In case (iii), both of the second clutch devices 220 are engaged. The first clutch device 21
As described above, 0 is in the engaged state unless an external operation is performed. Accordingly, when the second clutch device is forcibly engaged, the first clutch device 210 integrates the carrier via the second clutch device 220 in a state where the sun gear 31, the output shaft 23, and the carrier 34 are integrated. Power is input to the drive shaft 34 from the drive shaft 11.

Therefore, in case (iii), HST
Even if the motor 20 is out of order, the power from the drive shaft 11 can be transmitted to the outer wheel body 33, so that the vehicle can move forward.

In the traveling transmission 1 configured as described above, the following effects can be obtained in addition to the various effects described above. That is, a main drive shaft 10 operatively connected to the drive source 100, an HST 20 that continuously varies the power input through the main drive shaft 10 and outputs the power from an output shaft 23, A drive shaft 11 arranged substantially in parallel, to which power is input from a drive source 100, a planetary gear device 30 having a sun gear 31 supported on the output shaft 23 so as to be relatively non-rotatable, and a carrier of the planetary gear device A first clutch device 210 for engaging / disengaging the output shaft 23 with the carrier 34 and the drive shaft 11
And the second clutch device 220 that engages / disengages the vehicle. By controlling the engagement / switching of each of the clutch devices, the vehicle can be smoothly switched from the low-speed traveling mode to the high-speed traveling mode during traveling. Can be switched,
In addition, continuously variable transmission in each mode can be performed.

Further, in the present embodiment, HST
And a potentiometer 131 for detecting the swing angle of the shift lever. The first clutch device is engaged and the second clutch is engaged in accordance with the swing angle of the shift lever 140. Since the low-speed running mode in which the clutch device is disengaged and the high-speed running mode in which the first clutch device is disengaged and the second clutch device is engaged are switched, the operation of the HST and each clutch device can be performed with one operating lever. Operability can be improved.

Further, since the low-speed running mode and the high-speed running mode are switched by swinging the shift lever in one direction, the operability can be further improved.

In this embodiment, since the first clutch device 210 is configured to be in the engaged state unless the action of the pressure oil, the hydraulic circuit for each clutch device operates normally. Even if it is no longer the case
Vehicle traveling in the low-speed traveling mode (i) is enabled. That is, even if the hydraulic circuit for the clutch device fails, the first clutch device 210 remains engaged.
Therefore, traveling in case (i) (low-speed traveling mode) is possible.

Further, since the second clutch device is configured to be forcibly engaged, the vehicle can run even if the HST fails. That is, when the second clutch device is engaged, the drive shaft 1
Power is transmitted from 1 to the carrier. Therefore, when the sun gear and the carrier are integrated by the first clutch device, the outer ring body rotates in accordance with the rotation of the carrier, whereby the vehicle can run.

Further, since the multi-stage transmission (two-stage transmission in the present embodiment) is provided, a plurality of vehicle speed ratios can be obtained in accordance with the number of gears of the multi-stage transmission (see FIG. 4). . Further, since the gears of the multi-stage transmission are configured to be automatically switched, the operability of the vehicle can be improved.

In this embodiment, power is directly input from the main drive shaft 10 to the HST 20.
The present invention is not limited to such a form. For example,
Alternatively, as shown in FIG. 7, the HST 20 may be provided with an input shaft 21, and the input shaft 21 and the main drive shaft 10 may be connected by an appropriate power transmission mechanism.

Further, in the present embodiment, the main drive shaft 10 and the drive shaft 11 are provided separately, and the two are connected so that they cannot rotate relative to each other about the axis. However, they may be integrated. In such a case, the portion of the main drive shaft that supports the power transmission mechanism to the second clutch device is the drive shaft.

Further, in the present embodiment, the main drive shaft 10 and the drive shaft 11 are arranged coaxially, but the present invention is not limited to this embodiment. For example, as shown in FIG. 7, when the input shaft 21 is provided in the HST 20, the input shaft 21 is extended to the subsequent stage, and the input shaft 21 and the drive shaft 11 are connected so that they cannot rotate relative to each other about the axis. Thus, the drive shaft 11 can be configured to transmit power from a drive source via the main drive shaft 10.

In the present embodiment, the first
Although the clutch device and the second clutch device are multi-plate clutches, the present invention is, of course, not limited to such a form. For example, as shown in FIG. 8, a mechanical clutch such as a dog clutch or a constant mesh clutch is used, whereby the manufacturing cost can be reduced.

That is, as shown in FIG. 8, a clutch slider 231 for selectively switching between the first clutch device 210 'and the second clutch device 220' is provided, and the clutch slider 231 is operated by the hydraulic piston 232. can do. The hydraulic piston 232 is
The clutch slider 232 can be moved to the first clutch device 210 'engagement side as long as it is not affected by the pressure oil by the biasing member. The supply of pressure oil to the hydraulic piston 232 is performed by the range switching valve 7.
8 ', and the position control of the range switching valve 78' can be performed based on a signal from the controller 15 as in the present embodiment. In the embodiment shown in FIG. 8, in order to reduce the manufacturing cost, the emergency switching valve 74 is used.
Is not used.

[0093]

According to the vehicle transmission of the present invention, a main drive shaft operatively connected to a drive source and an input from the main drive shaft from the drive source are provided in accordance with the operation of the swash plate. A continuously variable transmission that outputs the power having undergone the continuously variable transmission from an output shaft, and a power that is provided substantially parallel to an output shaft of the continuously variable transmission and that is supplied with power from a drive source via the main drive shaft. A drive shaft, a planetary gear device having a sun gear supported non-rotatably on the output shaft, a first clutch device for engaging / disengaging the carrier and the output shaft, the carrier and the drive Since the vehicle is provided with the second clutch device that engages / disengages with the shaft, the shift operation from the low-speed running mode to the high-speed running mode can be performed without difficulty during vehicle running, and the speed change operation can be performed in each running mode. Gear shifting Kill.

Further, there is provided a traveling shift operation means connected to the swash plate, and a swing angle detecting device for detecting a swing angle of the traveling shift operation means, based on a signal from the swing angle detecting device. And a high-speed running mode in which the first clutch device is engaged and the second clutch device is disengaged, and a high-speed running mode in which the first clutch device is disengaged and the second clutch device is engaged. The operation of the continuously variable transmission and the clutch device can be performed by one traveling speed change operation means, and the operability can be improved.

Further, the operability can be further improved by swinging the traveling speed change operation means in one direction so as to switch from the low speed traveling mode to the high speed traveling mode in order.

If the first clutch device is engaged in a normal state and is disengaged based on a signal from the swing angle detecting device, the engagement / switching of the clutch device is performed. Even in the case where the device that performs the operation fails, the vehicle can run in the low-speed running mode. That is,
For example, when the clutch device is a hydraulic clutch, the vehicle can travel in the low-speed traveling mode even if the hydraulic circuit breaks down.

Further, if an engagement device for forcibly engaging the second clutch device is provided, even if the continuously variable transmission fails, the carrier can be transferred from the drive shaft through the second clutch device. Power can be transmitted to the vehicle. Therefore, even when the continuously variable transmission fails, the vehicle can run.

If a multi-stage transmission is provided, a speed ratio corresponding to the number of shift stages of the multi-stage transmission can be obtained.

[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 cross-sectional view of the planetary gear device in the traveling transmission shown in FIG. 1;

FIG. 4 is a waveform diagram showing a relationship between a vehicle speed and a tilt angle of a hydraulic pump swash plate in the vehicle shown in FIG. FIG.
(a) and (b) are waveform diagrams in a case where the multi-speed transmission is engaged with a low shift speed and a high shift speed, respectively.

FIG. 5 is a speed vector diagram of the planetary gear device in a low-speed traveling mode of case (i). Fig. 5 (a) and (b)
3A and 3B respectively show speed vector diagrams when the continuously variable transmission has a low output and a high output in the forward direction in case (i).

FIG. 6 is a speed vector diagram of the planetary gear device in a high-speed traveling mode of case (ii). Fig. 6 (a)-(c)
Shows velocity vector diagrams when the output of the continuously variable transmission is changed in the positive direction or the negative direction in case (ii), respectively.

FIG. 7 is a transmission path diagram of a vehicle to which a modified example of the traveling transmission shown in FIG. 1 is applied.

FIG. 8 is a hydraulic circuit diagram showing a modification of the first clutch device and the second clutch device in the traveling transmission shown in FIG. 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traveling transmission 10 Main drive shaft 11 Drive shaft 13 First driven shaft 20 HST 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 50 Multi-stage transmission device 100 Drive source 110 Drive wheel 210 First clutch device 220 Second clutch device

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B60K 17/06 B60K 17/06 H F16H 3/44 F16H 3/44 B 3/52 3/52 47/04 47/04 A D 61/04 61/04 F term (reference) 3D039 AA02 AA04 AA07 AB11 AC03 AC04 AC24 AC26 AC33 AC38 AC39 AC40 AC45 AC54 AC87 AC88 AC89 AD06 AD23 AD43 AD44 AD53 3D042 AA01 AA05 AA08 AA10 AB11 BA02 BA07 BA08 BA13 BC09 BD05 3J028 EA22 EA30 EB10 EB16 EB25 EB35 EB37 EB53 EB62 EB67 FA06 FB05 FB15 FC13 FC23 FC32 FC42 FC67 GA13 HA13 HA23 HC21 3J052 AA01 AA04 BA03 CA21 GC03 HA02 HA15 HA17 LA01

Claims (7)

[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 input from the main drive shaft, and the power that is continuously variable according to the operation of the swash plate is transmitted to the rear side of the transmission path. A continuously variable transmission that outputs from an extended output shaft; a drive that is disposed substantially parallel to the output shaft at a subsequent stage of the continuously variable transmission and that receives power from a drive source via the main drive shaft. A shaft, a sun gear supported non-rotatably on the output shaft, a planetary gear meshing with the sun gear and revolving around the sun gear, a carrier rotating according to the revolution of the planetary gear, and meshing with the planetary gear Internal gear is installed A planetary gear device having an outer ring body provided, a first clutch device for engaging / disconnecting the carrier and the output shaft, and a second clutch device for engaging / disconnecting the carrier and the drive shaft. A transmission for traveling, comprising: 2. A traveling speed change operating means connected to the swash plate, and a swing angle detecting device for detecting a swing angle of the traveling speed change operating means, based on a signal from the swing angle detecting device. A low-speed traveling mode in which the first clutch device is engaged and the second clutch device is disengaged; and a high-speed traveling mode in which the first clutch device is disengaged and the second clutch device is engaged. The traveling transmission according to claim 1, wherein the transmission is configured to switch between: 3. The traveling transmission according to claim 2, wherein the low speed traveling mode is switched to the high speed traveling mode by swinging the traveling speed change operation means in one direction. 4. The traveling according to claim 2, wherein the first clutch device is engaged in a normal state, and is disengaged based on a signal from the swing angle detection device. For transmission. 5. The traveling transmission according to claim 1, further comprising an engagement device for forcibly engaging the second clutch device. 6. A multi-stage transmission, which is arranged at a stage subsequent to a transmission path of the planetary gear device and is capable of shifting power output from an outer race of the planetary gear device in multiple stages. The traveling transmission according to any one of claims 1 to 6. 7. The multi-stage transmission has a high speed stage for driving the vehicle at a high speed, and a low speed stage for driving the vehicle at a low speed. When the vehicle runs under a high load, the low speed stage is set. 7. The traveling transmission according to claim 6, wherein the transmission is engaged so that when the vehicle travels in a low load state, the high speed gear is engaged.