JPS6225930Y2 - - Google Patents

Description

[Detailed description of the invention] This invention divides the output from the engine into the driving transmission system and other transmission systems, and also interposes a hydraulic clutch on the downstream side of the main transmission in the driving transmission system. The present invention relates to a gear shift operation unit for an agricultural tractor, wherein the hydraulic clutch is automatically engaged and engaged in conjunction with the gear shift operation of the main transmission device.

As described in, for example, Japanese Utility Model Application Publication No. 56-6624, the transmission control unit of the agricultural tractor mentioned above is a combination of a hydraulic clutch, which can be controlled remotely, and a main transmission. The hydraulic clutch is configured to automatically shift in conjunction with the operation of the transmission, allowing easy gear shifting without the need for a separate clutch switching operation, but the entire structure of the gear shifting operation part becomes complex and manufacturing costs increase. It has the disadvantage of being high.

Therefore, conventionally, when a super-deceleration transmission section is attached to such a transmission operation section structure, incorporating the super-reduction transmission section into this main transmission device results in further complicating the transmission operation section structure, and the super-deceleration This is extremely uneconomical considering that the automatic speed change operation section is only used for special operations such as trencher work and is used infrequently. A clutch is provided separately from the above-mentioned hydraulic clutch, and the clutch is configured to be manually operated separately.

For this reason, for example, when turning at normal speed to move to the next stroke during super-deceleration work such as plowing, the operation is extremely complicated.
There was room for improvement in terms of operation.

In view of the above-mentioned conventional situation, the purpose of this invention is to make reasonable improvements while taking advantage of the conventional advantages.
The purpose of this invention is to make it easy to operate the super-deceleration transmission section.

The characteristic configuration of the present invention is that, in the transmission operation section of the agricultural tractor mentioned above, a mechanically operated ultra-reduction transmission section is provided on the downstream side of the transmission of the hydraulic clutch, and a pressure oil supply path to the hydraulic clutch is provided with a mechanically operated super-reduction transmission section. A switching valve capable of switching the pressure oil supply path between a communicating state and a non-communicating state with respect to the drain flow path is connected, and the operating section of the switching valve and the operating tool of the super-deceleration transmission section are connected to each other. They are linked via a link operation mechanism that temporarily switches the switching valve to a communication state during a speed change operation of the deceleration speed change section, thereby disengaging the hydraulic clutch.

In other words, while taking advantage of cost reduction by configuring the ultra-reduction transmission part as a mechanically operated type, the ultra-reduction transmission part can be operated by operating the switching valve linked to the operation of the ultra-reduction transmission part. The necessary power on/off operation during operation can be performed using a hydraulic clutch provided to the main transmission.

Therefore, it is extremely easy to operate the super-reduction gear shift section.
In addition, it can be done quickly, and there is no need to provide a separate clutch for operating the ultra-reduction gearshift, so overall, the agricultural tractor has excellent operability and is advantageous in terms of production and economy. It has now become possible to provide a speed change operation section.

Next, embodiments of the present invention will be described in detail based on illustrative drawings.

As shown in FIG. 1, the power from the engine E is divided and transmitted within the transmission case M to a traveling transmission system and a PTO transmission system, and the traveling transmission system includes a main transmission 1, a hydraulic clutch 2, The transmission power is transmitted to the auxiliary transmission 3 and the super-reduction transmission 4 in that order, and the shifting power from the super-reduction transmission 4 is transmitted to a pair of left and right transmissions via a rear differential device 5 directly connected to the transmission case M. to the rear wheel 6, and
The power is transmitted to a pair of left and right steering front wheels 9 via a transmission shaft 7 and a front differential device 8, thereby forming a drive device for a four-wheel drive agricultural tractor.

In constructing the main speed change device 1, four idling gears G5, _G6 , G7, _G8 attached to the driven shaft S2 are selectively connected integrally to the driven shaft _S2 by operating two shift members 11a, 11b using two sets of speed change actuators 10a, 10b, so that a first speed state in which the power transmitted to the input shaft S1 is transmitted to the driven shaft S2 via the first and _fifth gears G1, _G5 , a _second speed state in which the power is transmitted to the driven shaft _S2 via the second and sixth gears G2, G6, a third speed state in which the power is transmitted to the driven shaft S2 via the second and sixth gears _G2 , _G6 , a seventh speed state in which the power is transmitted to the driven shaft _S2 via the third and seventh gears G2, _G6 , and a fifth speed state in which the power is transmitted to the driven shaft _S2 via the fourth and sixth gears G2, G6.
The transmission is configured to perform four speed changes: a third speed state via gears _G3 and _G7 , and a fourth speed state via _fourth and eighth gears G4 and _G8 .

In addition, in the PTO transmission system, a transmission device 12 for driving the work equipment is provided, and a hydraulic clutch 13 and
It is configured to transmit PTO shifting power to the working device via the PTO shaft 14.

In configuring the sub-transmission device 3, the transmission is transmitted from the main transmission device 1 to the third shaft _S3 by separately operating the two shift members 16a, 16b by the two operation actuators 15a, 15b installed therein. The generated power is transferred to the 4th shaft via the 10th and 14th gears G ₁₀ and G ₁₄ .
Forward high speed state transmitted to _S4 , 11th and 15th gears
Normal rotation low speed state via G ₁₁ , G ₁₅ , 9th, 12th, 1st
High speed reverse state via 13 gears G ₉ , G ₁₂ , G ₁₃ and 9th, 12th, 13th, 14th, 10th, 11th, 15th
It is configured to perform four speed changes including a reverse low speed state through gears G ₉ , G ₁₂ , G ₁₃ , G ₁₄ , G ₁₀ , G ₁₁ and G ₁₅ in that order.

The shift members 11a, 11b, 16a, 16
To operate the pump Pb, as shown in FIG.
The pressure oil supply line 17 from the neutral position N is
The two sets of actuators 10a, 10b in the main transmission 1 and the high/low speed switching actuator 15b in the subtransmission 3 are connected in parallel via the speed change valve _V1 configured as a position _N , F1 to _F8 switching valve, and the forward/reverse switching actuator 15a in the subtransmission 3 is connected via the forward/reverse switching valve _V2 configured as a three-position N, F, R switching valve including a neutral position N, so that eight forward and eight reverse speed changes are achieved by the speed change valve _V1 and the forward/reverse switching valve _V2 .

Further, each of the actuators 10a, 10b, 1
Four 3-position switching valves V ₁ block the passage of pressure oil from each valve V ₁ and V ₂ only when the plungers 18 of 5a and 15b are in the neutral position with the plungers 18 also serving as sliding spools. ,V ₂ ,V ₃ ,
A three-position switching valve V ₁ corresponding to the forward/reverse switching valve V ₂ and the hydraulic clutch ₂ constitute the V 4 and correspond to the forward/reverse switching valve V 2.
Three two-position switching valves V _{' 2} , V' 3 , which are individually operated by pilot pressure from the three three-position switching valves V ₂ , V ₃ , and V ₄ are connected to the oil passage 19 connecting _{the two} . V', ₄
are arranged in series, and the clutch 2 is configured to be automatically operated in accordance with the speed change operation of each valve V ₁ and V ₂ .

As shown in FIG. 1, the super-deceleration transmission 4 is configured such that the shifting power from the fourth shaft _S4 is transferred to the fourth shaft by operating a shift member 21 directly connected to the operating lever 20.
16, 17th gear G ₁₆ , G ₁₇ , 5th axis S ₅ , and 18th gear
Final output shaft S ₆ via 19th gear G ₁₈ and G ₁₉ in that order
The super deceleration state transmitted to the 4th axis _S4 and the final output shaft
The structure is configured to switch between the normal speed change state in which the _S6 is directly connected, and the 20th, 21st, 22nd, and 23rd gears.
Transmission of power to the front wheel drive transmission shaft 7 via G ₂₀ , G ₂₁ , G ₂₂ , G ₂₃ is interrupted or interrupted by the shift operation of the 23rd gear G ₂₃ to switch between the 4-drive state and the 2-drive state. It is structured as follows.

The speed change operation structure of the super-deceleration transmission 4 will be described in more detail below with reference to FIG. 2.

On the upper side of the valves V ₁ and V ₂ of the pressure oil supply path 17, there is a state in which the supply pressure oil is allowed to flow toward the valves V ₁ and V ₂ side, and a state in which the supply pressure oil and the return from the valves V ₁ and V ₂ side are allowed. A switching valve V ₃ is provided which has two positions, one in which oil is communicated with the drain passage 17a side, and the two-position switching valve V ₃ and the operating lever 20 are interposed.
A linked operation mechanism that temporarily switches the switching valve _V3 from the pressure oil supply permission state to the drain side communication state when the lever 20 is operated from one of the speed change states to the neutral state against the spring 22. The clutches 2 and 2 are interlocked via A, and are configured to automatically and temporarily disengage the clutch 2 during a switching operation of the super-reduction transmission 4.

In other words, the switching operation of the ultra-deceleration transmission 4 and the accompanying clutch operation can be performed with a single operation on the operating lever 20 using the hydraulic clutch 2 for the main transmission 1, thereby improving shift operability. It is configured to do so.

In addition, a super deceleration transmission device 4 configured with a mechanically operated type
The specific transmission structure can be changed in various ways.

In addition, the operating tool 20 and the switching valve of the super-deceleration transmission 4
The specific linkage structure for interlocking operation with the operation part of V ₃ so that the switching valve V ₃ is temporarily switched to a communicating state during a gear shift operation may be hydraulic, mechanical, or electrical. Various configuration changes are possible, and these linkage structures are collectively referred to as a linkage operation mechanism.

The present invention is directed to a speed change operation section in various types of agricultural tractors equipped with a mechanically operated ultra-reduction speed change section.

Note that although reference numerals are written in the claims section of the utility model registration for convenience of comparison with the drawings, the present invention is not limited to the structure of the attached drawings by such entry.

[Brief explanation of the drawing]

The drawings illustrate an embodiment of the speed change operation section of an agricultural tractor according to the present invention, with FIG. 1 being an overall schematic diagram showing the drive structure, and FIG. 2 being a schematic hydraulic circuit diagram showing the speed change operation structure. 1...Main transmission, 2...Hydraulic clutch, 4
... Ultra-reduction transmission section, 17 ... Pressure oil supply path, 17
a...Drain channel, 20...Operation tool, _V3 ...Switching valve, A...Linked operation mechanism.

Claims (1)

[Scope of utility model registration request] The output from the engine E is branched and transmitted to the driving transmission system and other transmission systems, and a hydraulic clutch 2 is interposed on the downstream side of the transmission of the main transmission 1 in the driving transmission system, and the transmission to the main transmission 1 is changed. In a gear shift operation section of an agricultural tractor configured such that the hydraulic clutch 2 is automatically operated intermittently in conjunction with the operation, a mechanically operated ultra-reduction gear is provided on the lower transmission side of the hydraulic clutch 2. A pressure oil supply path 1 to the hydraulic clutch 2 is provided.
7 is connected to a switching valve V ₃ that can switch the pressure oil supply path 17 between a state in which it communicates with the drain flow path 17a and a state in which it does not communicate with the drain flow path 17a, and connects the operation part of the switching valve V ₃ and the super-deceleration A link operation mechanism A is provided which temporarily switches the switching valve V ₃ to the operating tool 20 of the transmission section 4 into a communication state during the speed change operation of the super-deceleration transmission section 4 to disable the hydraulic clutch 2. A speed change operation unit for an agricultural tractor, characterized in that the gear change operation unit is linked through a transmission line.