JP2596516Y2 - Hydraulic transmission operation device in traveling equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift operating device in a traveling device of a working vehicle, such as a tractor, in which the speed of a traveling transmission is shifted via a shifting hydraulic actuator.

[0002]

2. Description of the Related Art In a working vehicle such as a tractor, there has been conventionally known a vehicle in which a traveling speed change device is operated by driving a hydraulic actuator to change the speed.
No. 9365 discloses a control valve that is linked to a transmission hydraulic cylinder and that communicates with a drain during a shift operation in an oil passage that communicates from a transmission control valve to a hydraulic clutch control valve, and that the hydraulic pressure is controlled by a pilot pressure applied to the control valve. An example in which the clutch control valve is switched is disclosed.

[0003]

In the prior art described in the above-mentioned publication, a control valve which is linked to a shift hydraulic cylinder and which communicates with a drain during a shift operation is arranged in an oil passage communicating from the shift control valve to the hydraulic clutch control valve. Since the hydraulic clutch control valve is switched by the pilot pressure applied to the control valve, the hydraulic clutch is controlled by the pilot pressure after the shift hydraulic cylinder is expanded and contracted by the shift operation at the start of the shift operation and the control valve is drained. When the valve is switched, the hydraulic oil of the hydraulic clutch returns to the tank. When the gearshift is completed, the gearshift operation is completed, the gearshift hydraulic cylinder expands and contracts, the control valve is closed, and the pilot pressure changes the hydraulic clutch control valve to change the travel hydraulic pressure. Since the oil passage communicates with the clutch, the gearshift operation takes precedence, and the response of switching the traveling hydraulic clutch is delayed, resulting in a smooth change. Of feeling it can not be expected.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a traveling-system transmission device is provided with a traveling hydraulic clutch, and a transmission control valve , which is operated in conjunction with a transmission lever, is controlled by a transmission control valve in accordance with each transmission position. connecting a plurality of shifting hydraulic cylinder being, travel
Shifting the hydraulic clutch control valve to turn on and off the hydraulic clutch
Linked with the control valve, and associated with the gearshift of the gearshift control valve
Hydraulic clutch control so that the traveling hydraulic clutch is disengaged
The valve is switched, and the hydraulic clutch control valve and traveling hydraulic pressure are
Branch from the oil path connecting the clutch, connect the control valve,
The control valve is linked to a shifting hydraulic cylinder to
The traveling hydraulic clutch is disengaged during the shifting operation of the
Control valve so that the hydraulic clutch
The control valve is driven by the traveling hydraulic clutch
After the switch is turned off, the shift control valve switching is completed.
Gently in response to the release of the traveling hydraulic clutch.
Be configured to hold state for a predetermined time
Has solved the above-described problem.

[0005]

When a shift lever is operated when a work vehicle such as a tractor attempts to shift while traveling, the shift control valve is switched.
In conjunction with this, the hydraulic clutch control valve
It switches to the direction to release the latch, so it is inside the traveling hydraulic clutch.
Hydraulic fluid returns to the tank and the traveling hydraulic clutch disengages,
On the other hand, when the shift control valve is switched,
The shift hydraulic cylinder connected to the shift control valve operates accordingly
The control valve that is linked to the
Pressure oil from the pressure clutch control valve side and the traveling hydraulic clutch side
To the tank, keeping the disengaged state of the traveling hydraulic clutch
Is done. When the shifting operation is completed, the hydraulic clutch system
The control valve slowly returns to run hydraulic oil from the hydraulic pump.
It is switched so that it passes through the hydraulic clutch for row
The hydraulic cylinder finishes the predetermined shifting operation and interlocks with it
When the control valve switches to the state before shifting, the pressure from the hydraulic pump
Oil travels through the already switched hydraulic clutch control valve
To the traveling hydraulic clutch.
The latch is connected smoothly and the traveling shift of the work vehicle is completed
I do.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows a schematic configuration of a tractor as a working vehicle to which the embodiment is applied. On the other hand, the main shift lever 3, the auxiliary shift lever 4, and the shuttle shift lever 5 are separately provided.

Here, the driving system of the tractor 1 will be schematically described with reference to FIG.
The transmission 8 connected via the second transmission includes a second main transmission mechanism 9, a first main transmission mechanism 10, a traveling hydraulic clutch 11, a forward / reverse switching mechanism 12, a first auxiliary transmission mechanism 13, and a second auxiliary transmission mechanism. By being transmitted to the rear wheel 16 of the tractor 1 via the differential device 14 and the differential device 15, a traveling drive system that rotationally drives the drive wheels is configured. In addition, since the traveling transmission 8 is configured to be transmitted to the PTO shaft 21 via the first PTO transmission mechanism 17, the second PTO transmission mechanism 18, the transmission shaft 19, and the third PTO transmission mechanism 20, a power source such as a work machine is provided. A PTO shaft drive system that rotationally drives the PTO shaft 21 is configured.

The first main transmission mechanism 10 switches from a neutral speed to a first speed or a second speed.
The shift operation is performed by a first hydraulic cylinder 22 as a hydraulic actuator. The second main transmission mechanism 9 switches from a neutral gear to a third gear or a fourth gear, and is operated by a second hydraulic cylinder 23 as a hydraulic actuator. Further, the first auxiliary transmission mechanism 13 switches the output rotation of the forward / reverse switching mechanism 12 between high and low two stages of H and L stages, and a third hydraulic cylinder 2 as a hydraulic actuator.
The gear 4 is operated to change gears. The operation of the first hydraulic cylinder 22, the second hydraulic cylinder 23, and the third hydraulic cylinder 24 is controlled in accordance with the switching position of a later-described shift control valve switched by the main shift lever 3. I have.

The forward / reverse switching mechanism 12 transmits the output rotation of the traveling hydraulic clutch 11 to the first auxiliary transmission mechanism 13 as it is or in reverse, and transmits a shift rail 25 interlocked with the shuttle transmission lever 5. The switching operation is performed via the switch. Further, the second sub-transmission mechanism 14 switches the output rotation of the first sub-transmission mechanism 13 between high and low two stages of an H stage and an L stage, and is operated through a shift rail 26 interlocked with the sub-transmission lever 4. It has become so.

FIG. 3 shows a hydraulic circuit of a traveling system hydraulic control device for controlling the on / off control of the traveling hydraulic clutch 11 and the operation of the first to third hydraulic cylinders 22 to 24. This hydraulic circuit is used in common with the hydraulic control device 27 for the power steering device and the hydraulic control device 28 for the quick turn device provided in the tractor 1. Shunt valve 30 for supplying the pressurized oil, and shunt valve 3
And a shift control valve 31 and a hydraulic clutch control valve 32 to which the pressure oil is supplied via the control valves 0 and 0, respectively. The traveling hydraulic clutch 1 is connected via the hydraulic clutch control valve 32.
1 is connected to each of the first hydraulic cylinder 22, the second hydraulic cylinder 23, and the third hydraulic cylinder 2 via the shift control valve 31.
4 are connected to each other.

The flow dividing valve 30 includes two pressure control valves 30a and 30b connected in parallel to the oil pump 29.
And a switching valve 30c connected to the downstream side of one of the pressure control valves 30a. The switching valve 30c is connected to the shift control valve 31 and the hydraulic clutch control valve 32 via an oil passage L1. Then, it is connected to the hydraulic control device 28 for the quick turn device via the oil passage L2. The other pressure control valve 30b is connected to the power steering device hydraulic control device 27 via the oil passage L3.

The switching valve 30c is a spring-return type solenoid valve switching type. In the spring-return state, the oil passage L2 communicates with the drain side, and the oil passage L2 and the pressure control valve 30a are cut off. At the time of energization, the communication between the oil passage L2 and the drain side is cut off, and the oil passages L1 and L2 are connected to the oil pump 29 via the pressure control valve 30a.

Microswitches 33 and 34 for controlling the energization of the switching valve 30c are provided in contact with the shift rails 25 and 26 to detect the movement of the shift rails 25 and 26, respectively. At the time of shifting operation of the shift lever 4, the micro switch 33 or the micro switch 34 having a normally closed contact is turned off to return the switching valve 30c to a spring, thereby connecting the oil path L2 to the drain side. .

The shift control valve 31 is of a rotary switching type in which N (neutral) and F1 to F8 switching positions are continuous, and is switched by the main shift lever 3. The first hydraulic cylinder 22, the second hydraulic cylinder 23, and the third hydraulic cylinder 24 are controlled to expand and contract, respectively, in accordance with the respective switching positions of the shift control valve 31. For example, at the N position, the first hydraulic cylinder 22 and the second hydraulic cylinder 22
When both the hydraulic cylinders 23 are controlled to the neutral intermediate extension position, the first main transmission mechanism 10 and the second main transmission mechanism 9 are both shifted to the neutral speed. Also, N, F
In each of the switching positions of F1, F2, F3, and F4, the third hydraulic cylinder 24 contracts, and the first subtransmission mechanism 13 enters the low-speed L stage. In each of the switching positions of F5, F6, F7, and F8, the third hydraulic cylinder 24 24 is extended and the first sub-transmission mechanism 13 is driven at high speed H
It becomes a step. In the switching position of F1, F2, F5, F6, the second main transmission mechanism 9 is in the neutral stage, whereas
The first hydraulic cylinder 22 is controlled to expand and contract, and the first main transmission mechanism 10 shifts to F1 and F6 in the first speed at the switching position between F1 and F5.
At the second switching position. At the switching position of F3, F4, F7, and F8, the first main transmission mechanism 10 is in the neutral stage, whereas the second hydraulic cylinder 23 is controlled to expand and contract, so that the second main transmission mechanism 9 becomes F3, F7. The shift operation is carried out to the third speed at the switch position and to the fourth speed at the switch positions of F4 and F8.

The hydraulic clutch control valve 32 is a two-position switching valve provided with a spool 32a that is pushed and operated following a disk-shaped cam 31a that also serves as a positioning plate interlocked with the shift control valve 31. Has an orifice 35a at the other end thereof, has an oil chamber 35 with a built-in spring 35b, and has a spool 32a abutting on the cam 31a.
A biasing force of a spring 35b acts on the other end 32b of the spring. When the shift control valve 31 is at the N position and in the middle of switching to each of the switching positions F1 to F8, the hydraulic clutch control valve 32 causes the spool 32a to resist the urging force of the spring 35b by the cam 31a. The hydraulic passage L5 to the traveling hydraulic clutch 11
Is connected to the drain side, and the shift control valve 31 is connected to F1 to F8.
The spool 32a is pressed by the return force of the spring 35b when the oil chamber 35
The oil sucked into the oil passage receives the resistance of the orifice 35a, so that the oil passage L1 is returned slowly to connect the oil passage L1 and the oil passage L5 to the traveling hydraulic clutch 11 after a short period of time. The traveling hydraulic clutch 11 disconnects the traveling drive system of the tractor 1 when the oil passage L5 is connected to the drain side,
When the oil passage L5 and the oil passage L1 are connected and the drain control valve 38, 39, or 40, which will be described later, is in a non-return valve state, it operates by the supplied pressure oil to connect the traveling drive system. Has become.

A boost control valve 36 is connected in the middle of an oil passage L5 to the traveling hydraulic clutch 11.
The pressure control valve 36 performs drain control so as to gradually increase the pressure of the pressure oil supplied to the traveling hydraulic clutch 11, and the pressure of the oil passage L5 is set at a pressure lower than the pressure set by the pressure control valve 30a. A spring return type internal pilot type pressure control valve 36a for draining oil, and an accumulator 36c connected to the oil passage L5 via an orifice 36b to supply a pressure against the oil pressure to the pressure control valve 36a.
And an accumulator 36d connected to the third hydraulic cylinder 24.

The drain control valves 38, 39 and 40 are spring-return type two-position switching valves in which a spool is pushed and operated.
In the pushing operation state of the spool, the oil passage L4 is connected to the drain side to reduce the hydraulic pressure, and in the spring return state, the drain state of the oil passage L4 is blocked to maintain the hydraulic pressure. The drain control valve 38 is set in such a manner as to return to the spring only at the neutral position, the extension limit and the contraction limit in conjunction with the first hydraulic cylinder 22, and the spool is pushed during the operation. Similarly, the drain control valve 39 is installed such that the spring returns only at the neutral position, the extension limit and the contraction limit of the second hydraulic cylinder 23, and the spool is pushed during the operation. In addition, the drain control valve 40 is set so as to return to a spring only at its contraction limit and extension limit in conjunction with the third hydraulic cylinder 24, and the spool is pushed and operated during its operation.

Here, as shown in FIG. 1, the first main transmission mechanism 10, the second main transmission mechanism 9, and the first sub transmission mechanism 13
Shift rails 41, 42, 43 for switching operation of
Are located on the same side of the transmission case 44 and their ends are relatively small openings 44a provided in the transmission case 44.
Are gathered near. And this transmission case 44
, A valve case 45 is externally attached so as to cover the opening 44a.

The valve case 45 is provided with the shift control valve 3.
1. Hydraulic clutch control valve 32, drain control valves 38, 3
9, 40 together with the first to third hydraulic cylinders 22,
23 and 24 are concentrated and assembled.
The transmission case 44 is connected to the bolt 47 and the pin 48 through the transmission case 6.
It is fixed to. The first to third hydraulic cylinders 22, 23, and 24 in the valve case 45 are arranged in parallel with each other with the distal ends of the piston rods 22a, 23a, and 24a gathered near the opening 44a of the transmission case 44. As shown in FIG. 1, one end of each of the shift rods 52, 53, and 54 inserted into the opening 44a of the transmission case 44 has a connecting member at the distal end of each of the piston rods 22a, 23a, and 24a. Are connected via The other ends of the shift rods 52, 53, 54 are connected to the ends of the shift rails 41, 42, 43, respectively, so that the first main transmission mechanism 10, the second main transmission mechanism 9,
And the first sub-transmission mechanism 13 includes the first hydraulic cylinder 22 and the second
The switching operation is performed by the hydraulic cylinder 23 and the third hydraulic cylinder 24, respectively.

Next, the operation of the working vehicle shift operation device according to the embodiment constructed as described above will be described. First, in the state where the auxiliary shift lever 4 or the shuttle shift lever 5 is not operated. Micro switch 3
Reference numerals 3 and 34 are ON, and the switching valve 30c of the flow dividing valve 30 is switched to connect the oil passage L2 to the pressure control valve 30a. Therefore, the shift control valve 31 and the hydraulic clutch control valve 3
2, the pressure oil of the pressure set by the pressure control valve 30a is directly supplied.

In this state, when the main shift lever 3 is switched to the N position, that is, when the shift control valve 31 is switched to the N position, the spool 32a of the hydraulic clutch control valve 32 is pushed by the cam 31a of the shift control valve 31. The hydraulic clutch control valve 32 has been switched to the position where the oil passage L5 to the traveling hydraulic clutch 11 is connected to the drain side, and the traveling hydraulic clutch 11 disconnects the traveling drive system of the tractor 1 because it has been moved. ing. At this time, the third gear interlockingly connected to the shift control valve 31
The hydraulic cylinder 24 is contracted and the first auxiliary transmission mechanism 13 is switched to the low-speed L stage through the path of the piston rod 24 a, the shift rod 54, and the shift rail 43, and the drain control valve operatively connected to the third hydraulic cylinder 24. Reference numeral 40 communicates with the drain, and the hydraulic pressure is released. In addition, the first hydraulic cylinder 22 and the second hydraulic cylinder 23 are both controlled to the neutral extended positions, and the first main transmission mechanism 10 and the first main transmission mechanism 10 pass through the paths of the piston rods 22a, 23a, the shift rods 52, 53, and the shift rails 41, 42. The second main transmission mechanism 9 is in a neutral stage.

Next, when the shift control valve 31 is switched to the F1 position by the main shift lever 3, the first hydraulic cylinder 22 is extended, and the first main shift mechanism is moved along the path of the piston rod 22a, the shift rod 52, and the shift rail 41. The gear 10 is shifted to the first speed. At this time, when the first hydraulic cylinder 22 is performing the extension operation and the gear shifting operation to the first gear is not completed, the spool 32a of the hydraulic clutch control valve 32 is pressed by the cam 31a as described above. But the cam 31
When the valley of a reaches the spool 32a, the spool becomes
The gradual return operation is performed while receiving the resistance of the orifice 35a. During this return operation, the oil passages L1 and L5 are disconnected and the traveling hydraulic clutch 11 is kept off to complete the switching. The first hydraulic cylinder 22 operates to shift to the first speed, and the convex portion of the spool pushes the drain control valve 38 to switch the oil passage L4 to the drain side to depressurize the oil pressure. Since the operation is performed while the clutch control valve 32 is in the disengaged state, the traveling hydraulic clutch 11 continues to be in the disengaged state, and smooth shifting operation is guaranteed.

Then, when the shifting operation of the first hydraulic cylinder 22 is completed and the extension limit is reached, the drain control valve 38 returns to the spring state and prevents the drain state of the oil passage L4. At this time, since the hydraulic clutch control valve 32 has already been switched and the oil passage L5 is in communication with the oil pump 29, the traveling hydraulic clutch 11 receives the supply of pressure oil without delay, rises without delay in response, and travels. Automatically connect the system. Since the pressure of the pressure oil supplied to the traveling hydraulic clutch 11 is controlled by the boost control valve 36 so as to gradually increase, the traveling hydraulic clutch 11 is connected with a small shock and the engine is stopped without engine stall. 6 is transmitted to the rear wheels 16.

Also, when the main shift lever 3 is switched to another shift position, the shift control valve 31 and the cam 31a operate in conjunction with each other, whereby the second hydraulic cylinder 23 or the third
Since the hydraulic cylinder 24 and the hydraulic clutch control valve 32 operate at the same timing as described above, a desired shift can be smoothly performed with good responsiveness.

On the other hand, when the shuttle shift lever 5 is switched, the shift rail 25 moves and the micro switch 3 is moved.
3 is turned off, the switching valve 30c of the flow dividing valve 30 is de-energized, and the oil path L1 is energized to the drain side by spring return. Therefore, even when the shift control valve 31 is at an arbitrary switching position, the hydraulic oil in the oil passage L5 is drained and the traveling hydraulic clutch 11 is automatically disengaged. , The operation is smoothly switched to the forward gear or the reverse gear. When this switching operation is completed, the micro switch 33 is turned on, the switching valve 30c is switched by energization, and the oil passage L1 is connected to the pressure control valve 30a via the check valve 30d. Therefore, the pressure oil from the pressure control valve 30a is supplied to the oil passage L1, the hydraulic clutch control valve 32, and the oil passage L5.
Is supplied to the traveling hydraulic clutch 11, and the traveling hydraulic clutch 11 is automatically connected in this manner. In addition,
In the case of the switching operation of the auxiliary transmission lever 4, the switching valve 30 c is similarly switched, whereby the traveling hydraulic clutch 1 is switched.
1 is automatically intermittently controlled.

[0026]

[Effects of the Invention] In the present invention, the traveling hydraulic clutch 11 is connected.
The hydraulic clutch control valve 32 to be disengaged is connected to the shift control valve 31.
And the hydraulic pressure is changed when the shift control valve 31 is shifted.
The latch control valve 32 is switched, and the traveling hydraulic
Since the switch 11 is configured to be turned off, the shifting operation is started.
At times, the hydraulic clutch control valve 32 is reliably switched for traveling.
The hydraulic clutch 11 can be disengaged,
Disconnect the hydraulic clutch for traveling ahead of the shifting operation
The problem that the gear shifting is delayed and smooth shifting cannot be performed.
Can be turned off. Also, the hydraulic clutch control valve 32
Is associated with the traveling hydraulic clutch
After the switch 11 is turned off, the shift control valve 31
When the gear change is completed, the operation returns slowly and the hydraulic
The cut state of the latch 11 is held for a predetermined time.
The operation is slower than the hydraulic clutch control valve 32.
Control valves 38, 39, and 40 have hydraulic clutches for traveling.
Disengage the traveling hydraulic clutch 11 until the
State, and the hydraulic clutch
The transmission is turned on, causing the traveling transmission to produce gear noise, etc.
And running speed can be changed more smoothly.
it can.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a tractor drive system.

FIG. 2 is a schematic configuration diagram of a tractor.

FIG. 3 is a hydraulic circuit diagram of a traveling system hydraulic control device for a tractor.

[Explanation of symbols]

 Reference Signs List 1 tractor 3 main transmission lever 8 traveling transmission 11 traveling hydraulic clutch 22 first hydraulic cylinder 22a piston rod 23 second hydraulic cylinder 23a piston rod 24 third hydraulic cylinder 24a piston rod 31 shift control valve 32 hydraulic clutch control valve 35 Oil chambers 38, 39, 40 Drain control valves 41, 42, 43 Shift rails 44 Transmission case 45 Valve cases 49, 50, 51 Connecting members 52, 53, 54 Shift rod

──────────────────────────────────────────────────続 き Continued from the front page Examiner Satoshi Murakami (56) References JP-A-2-199362 (JP, A) JP-A-4-131523 (JP, A) (58) Fields investigated (Int. Cl. ⁶⁾ , DB name) F16H 61/26-63/38

Claims (1)

(57) [Scope of request for utility model registration] 1. A traveling hydraulic clutch for a traveling system transmission.
A shift control valve (31) interposed with (11) and operated in conjunction with a shift lever is provided with a plurality of shift hydraulic cylinders (22), (23), which are shift-controlled in accordance with each shift position .
(24) is connected and the traveling hydraulic clutch (11) is turned on and off.
The hydraulic clutch control valve (32)
In conjunction with 1), the shift control valve (31) is shifted.
So that the traveling hydraulic clutch (11) is disengaged
The pressure clutch control valve (32) is switched, and the hydraulic clutch
Switch control valve (32) and the traveling hydraulic clutch (11).
Control valve (38), (39),
(40), and the control valves (38), (39),
(40) is replaced with the shifting hydraulic cylinders (22), (23),
In conjunction with (24), the transmission hydraulic cylinder (2
2) During shifting operations of (23) and (24),
The control valves (38) and (3) are set so that the latch (11) is turned off.
9) and (40) are switched, and the hydraulic clutch control is further performed.
The valve (32) travels with the shift control of the shift control valve (31).
After switching the hydraulic clutch (11) to be disengaged,
Slow return operation with completion of switching of the shift control valve (31)
The disengagement state of the traveling hydraulic clutch (11) is maintained for a predetermined time.
A hydraulic shift operation device for a traveling device, characterized in that the hydraulic transmission device is configured to be held over a range.