JPH0241668B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to the drive of a working vehicle, such as an agricultural tractor or a construction vehicle, which is equipped with two sets of transmission systems, a travel transmission system and a PTO transmission system. Regarding structure.

[Conventional technology]

In agricultural tractors, which are an example of work vehicles,
There is a structure as shown in FIG. In other words,
The power branched from the input shaft S ₁ that receives power from the prime mover E is transmitted to the traveling device via the gear transmission mechanism 1, and another power branched from the input shaft S ₁ is transmitted to the PTO shaft 12. It is a structure.

[Problem to be solved by the invention]

With the above structure, when changing the speed of the gear transmission mechanism 1, the main clutch C, which is located on the upper side of the transmission (on the side of the prime mover E) than the input shaft _S1 , is first disengaged. Then, the shift member 20 engaged with the gear Gb is removed from this gear Gb, the other shift member 20 is engaged with the gear Gb, and the main clutch C is engaged again.

In this series of operations, when the shift member 20 is engaged with the gear Gb after the main clutch C is disengaged, the shift member 20 side is connected to the ground via the passive shaft _S2 and rotates at a substantially constant number of times. The inertial weight of gear Gb on the free rotation side becomes a problem. In other words, in the structure shown in Fig. 4, gear Gb has input shaft S ₁ ,
A drive-side gear Ga fixed to this input shaft S ₁ and another gear Gb that meshes with this drive-side gear Ga
Because they are connected, the inertial weight on the gear Gb side is relatively large.

Therefore, even if an attempt is made to cause the shift member to engage with the gear on the occlusal side that has a different rotation speed, the rotation speed of the gear will not easily match the rotation speed of the shift member, making it difficult to operate the shift member toward the occlusion side. I become confused.

Also, with the structure shown in Figure 4, when main clutch C is disengaged to stop the aircraft from moving, the PTO
The shaft 12 also stops. As a result, when the machine is stopped, work cannot be performed using the power from the PTO shaft 12.

Here, the present invention prevents the speed change operation of the gear transmission mechanism for traveling from becoming heavy, and also prevents the aircraft from stopping.
The purpose is to configure it so that work can be performed using power from the PTO shaft.

[Means to solve the problem]

The feature of the present invention is that the drive structure of the working vehicle is configured as follows. In other words, power branched from an input shaft that receives power from the prime mover is transmitted to the traveling device via a gear transmission mechanism, and another power branched from the input shaft is transmitted to the PTO shaft. , a clutch which is turned on and off during a gear shifting operation of the gear shifting mechanism to enable the gear shifting operation of the gear shifting mechanism is disposed on the downstream side of the transmission of the gear shifting mechanism, and its functions and effects are as follows. It is as follows.

[Effect]

With the configuration as described above, for example, as shown in FIG. 2, when the clutch 2 on the lower side of the transmission is disengaged and the shift member 20 is engaged with the gear G ₅ , for example, as shown in FIG. do. In this case, since the gear _G5 is rotating at a substantially constant rotation speed due to the power from the prime mover E, the shift member 20
is the free rotation side. And since the only thing connected to the shift member 20 is the passive shaft _S2 ,
The inertia weight on the shift member 20 side is smaller than that of the conventional structure shown in FIG.

Therefore, when the shift member 20 is engaged with the gear _G5 after the clutch 2 is disengaged, the shift member 2
The rotation speed of gear G ₅ will match the rotation speed of gear G 5 relatively quickly, and the operation of the shift member 20 will not be particularly heavy.

As shown in Figure 2, the input shaft _S1 branches into the travel system and the PTO system, so even if you disengage the clutch 2 on the travel system side to stop the aircraft,
Power flows to the PTO system side (PTO shaft 12 side).

〔Effect of the invention〕

As described above, the speed change operation of the gear transmission mechanism of the traveling system can be performed relatively easily, and the speed change operability can be improved.

Furthermore, work can now be done using power from the PTO axis while the aircraft is stopped, improving work efficiency.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

As shown in Figures 1 and 2, the power transmitted from the prime mover E to the input shaft _S1 is transferred to the transmission case M through an internal main gear transmission mechanism 1, a multi-plate hydraulic clutch 2, and an auxiliary gear transmission. The transmission is configured to be transmitted to the mechanism 3 and the super deceleration mechanism 4 in that order, and
It is configured to transmit power from the super speed reduction mechanism 4 to the rear wheels 5 via the differential device 7. and,
Power is transmitted to the front wheels 6 via a transmission shaft 8 and a differential device 9.
The drive structure of a four-wheel drive type working vehicle such as an agricultural tractor is configured so that the power is transmitted to each of the four wheels.

Furthermore, within the mission case M, the power of the input shaft S ₁ is transmitted through a PTO transmission mechanism 10 and a multi-disc hydraulic clutch 11 to drive a working device.
The signal is configured to be transmitted to the PTO shaft 12.

Each of the transmission mechanisms 1, 3, 4, and 10 will be described in detail below.

To configure the main gear transmission mechanism 1, four drive side gears G ₁ , G ₂ , G ₃ , G ₄ each having a different number of teeth are arranged side by side on the input shaft S ₁ so as to be rotatable integrally, and each of them is The four driven gears G ₅ , G ₆ , G ₇ , and G ₈ that are always engaged with the driving gears G ₁ , G ₂ , G ₃ , and G ₄ are freely rotated on the driven shaft S ₂ of the traveling system. It can be installed freely.
Then, the adjacent passive gears G ₅ and G ₆ and G ₇ and G ₈
between the adjacent passive gears G ₅ ,
Two synchronized mesh shift devices 1 that selectively connect one of G ₆ , G ₇ , and G ₈ to the passive shaft S ₂
3a, 13b are provided, and this shift device 13a,
The vehicle is configured to perform a four-speed shift by operating the gear 13b.

The auxiliary gear transmission mechanism 3 includes a third shaft S ₃ that receives power transmission from the main gear transmission mechanism 1 via the clutch 2, and a gear G ₉ that is constantly engaged with a relay gear G _B for reverse movement; A first gear pair GG ₁ is formed by integrally connecting two gears G ₁₀ and G ₁₁ each having a different number of teeth,
Each is attached so that it can rotate freely. Then, the gear G ₁₂ that is always engaged with the relay gear G _B for reverse movement and the first
A gear that constantly engages gear G ₁₀ on one side of gear pair GG ₁
A second gear pair GG ₂ integrally connected with G ₁₃ , and a first
A gear that constantly meshes with the other gear G ₁₁ of gear pair GG ₁
G ₁₄ are respectively attached to the fourth shaft S ₄ so as to be freely rotatable. And between the gear G ₉ and the first gear pair GG ₁ and between the second gear pair GG ₂ and the gear G ₁₄ , respectively,
Those gears G ₉ , G ₁₄ and the first and second gear pair GG ₁ ,
A synchronized mesh shift device 1 that selectively integrally connects the GG ₂ to the third shaft S ₃ or the fourth shaft S ₄
4,15 are provided. Thereby, the configuration is such that forward/reverse switching is performed by operating the shift device 14 on the third shaft S3 _side , and high/low speed switching is performed by operating the shift device 15 on the fourth shaft _S4 side.

The super-reduction gear mechanism 4 is configured by providing a final output shaft _S6 coaxially with the fourth shaft _S4 , and transmitting the power from the fourth shaft _S4 to the fifth shaft through the super-reduction gear mechanism 4a.
A shift device 16 is provided for switching between a state in which transmission is made to the final output shaft S ₆ while bypassing the shaft S ₅ and a state in which the final output shaft S ₆ is directly connected to the fourth shaft S ₄ . As a result, the shift device 16 is operated to switch between the super deceleration state and the direct connection state.

In other words, the configuration is such that the main gear transmission mechanism 1, the auxiliary gear transmission mechanism 3, and the super-reduction mechanism 4 can be shifted in 16 steps in each of the forward and reverse directions. Then, the power transmitted to the final output shaft S ₆ is transferred to the PTO
Through a relay gear G _F freely rotatably attached to the output shaft S ₈ , the gear is interlocked with the transmission shaft 8 to the front wheels 6, and the lower transmission side gear G _F1 meshing with the relay gear G _F is powered. It is configured to be freely shiftable between a transmission state and a non-transmission state, and is configured to be switched between a four-wheel drive state and a two-wheel drive state.

Like the main gear transmission mechanism 1, the PTO transmission mechanism 10 is composed of four drive side gears G ₁ , G ₂ ,
Gears G ₁₅ and G ₁₆ that are always engaged with G ₃ and G ₄ separately,
G ₁₇ and G ₁₈ are each freely rotatably attached to the passive shaft S ₇ of the PTO system. And those adjacent gears
Each gear G ₁₅ , G ₁₆ between G ₁₅ and G ₁₆ and G 17 _and G ₁₈ ,
G ₁₇ and G ₁₈ are alternatively integrally connected to the passive shaft S ₇ 2
Synchronized mesh shift device 17a, 1
7b, and is configured to perform PTO system 4-speed shifting.

Each of the synchronized mesh shift devices 13
a, 13b, 14, 15, 17a, 17b, as shown in FIG. It is installed so that it can slide freely. Then, the shift fork 21 for the shift member 20 attached to each shaft S ₂ , S ₃ , S ₄ , S ₇ so as to be integrally rotatable and shift operable,
The plunger 19 is connected to an intermediate portion of the plunger 19, and the plunger 19 is slid by supplying pressure oil to the pilot cylinder 18.

Next, the hydraulic operation structure of each transmission mechanism 1, 3, 10 will be explained in detail with reference to FIGS. 2 and 3.

In the main gear transmission mechanism 1 and the auxiliary gear transmission mechanism 3, the pressure oil supply path 22 from the hydraulic pump P is connected to the two shift devices 13a, 13b in the main gear transmission mechanism 1 via the traveling speed change valve _V1 , and It is connected in parallel to each pilot cylinder 18 of the shift device 15 for high/low switching in the auxiliary gear transmission mechanism 3. In parallel with the traveling transmission system, a pressure oil supply path 22 is connected to a pilot cylinder ₁₈ of a shift device 14 for forward/reverse switching in the auxiliary gear transmission mechanism 3 via a forward/reverse switching valve V2.

Set the driving speed change valve V ₁ to 9 including the neutral position N.
It is configured as a position (N, F ₁ to F ₈ ) switching valve, and by operating the traveling speed change valve V ₁ , eight combinations of operating states of the three shift devices 13a, 13b, and 15 connected thereto are displayed. It is configured to perform an 8-speed gear shift operation. Furthermore, by operating the forward/reverse switching valve _V2 , it is possible to change the speed to eight speeds each.

The plungers 19 of each shift device 13a, 13b, 14, 15 are also used as spools, and the valves V ₁ , V ₂ are used for driving speed change and forward/reverse switching.
Four three-position switching valves V ₁ , V ₂ ,
It constitutes V ₃ and V ₄ . The three-position switching valve V ₁ for forward/reverse switching is connected to the hydraulic operating part of the clutch 2 for traveling gear shifting by one oil passage 23, and the other three three-position switching valves V ₂ , V ₃ are connected. , V' 3 and V _{' 4} are installed in series in the oil passage 23, each of which is operated by pilot pressure from V' ₂ , V' ₃ , and V' ₄ .

As a result, both the shift device 14 for forward/reverse switching and the shift device 15 for elevation/lower switching are in a non-neutral state, and only one of the two shift devices 13a, 13b in the main gear transmission mechanism 1 is in a non-neutral position. The clutch 2 for the traveling gear shift is engaged and operated only when the vehicle is in the position, and the traveling gear shifting valve V ₁ or the forward/reverse switching valve V ₂ is operated from one gear shift position to another gear shift position. At that time, any shift device 20 that was in an operating state
When the shift member 20 returns to the neutral state, the clutch 2 for the travel shift is automatically disengaged, and at the time any of the shift members 20 in the neutral state is switched to the operating state, the clutch 2 for the travel shift is automatically operated. It is configured so that it is automatically entered and operated.

In the PTO transmission mechanism 10, as shown in FIG. 3, a hydraulic pump P is connected to a PTO transmission valve _V3 ,
The pilot cylinders 18 of the two shift devices 17a and 17b are connected in parallel, and the
The two shift devices 17 are operated by operating the PTO speed change valve V ₃ configured as a position (n, f ₁ to f ₄ ) switching valve.
It is configured to provide four combinations of operating states a and 17b to perform a PTO system four-speed shifting operation.

Then, the plungers 19 of the shift devices 17a and 17b are used as spools to configure two 3-position switching valves V ₅ and V ₆ , and the pilot pressure from these 3-position switching valves V ₅ and V ₆ is used to control each valve separately. Two operated two-position switching valves V' ₅ and V' ₆ are interposed in series in an oil passage 24 connecting the hydraulic pump P and the hydraulic operating section of the clutch 11 for PTO shifting. As a result, the PTO gear shifting clutch 11 is configured to be automatically disengaged only when both shift devices 17a and 17b are brought into a neutral state due to the operation of the PTO gear shifting valve _V3 . .

In other words, as shown in Figures 1 and 2, with the clutch 11 disconnecting from the working equipment side, the shift is performed with a small shift force that is sufficient to resist the inertial weight of the passive shaft _S7 of the PTO system. Devices 17a, 17b
can be shifted to the entry side. This reduces the size of each shift device 17a, 17b, as well as the hydraulic structure for shift operation and the transmission case M.
It is designed to be smaller.

The specific number of gears and the arrangement of gears of each transmission mechanism 1, 3, 4, 10 can be changed in various ways, and the shift devices 13a, 13b, etc. can also be of synchronized mesh type. Instead, it is possible to apply various types of conventionally known power shift devices.

Furthermore, with changes in the models of the shift devices 13a, 13b, etc., the specific operating structure of each transmission mechanism 1, 3, 4, 10 and clutches 2, 11 has also been changed in various ways, such as using a hydraulic type or an electric type. It is possible.

The present invention can be applied to various types of work vehicles such as agricultural and construction vehicles, and depending on the type of the work vehicle, for example, the auxiliary gear transmission mechanism or super reduction mechanism can be omitted as appropriate, or the transmission The order may be changed, and the main feature is that the clutch 2 for traveling transmission is interposed on the downstream side of the main gear transmission mechanism 1.

[Brief explanation of drawings]

The drawings show an embodiment of the drive structure for a working vehicle according to the present invention, FIG. 1 is an overall cross-sectional view of the mission case, FIG. 2 is an overall schematic view of the inside of the mission case,
FIG. 3 is a schematic circuit diagram showing a hydraulic operating structure, and FIG. 4 is a schematic diagram showing a conventional structure. 1...Gear transmission mechanism, 2...Clutch, 12...
...PTO axis, E...prime mover, S ₁ ...input shaft.

Claims (1)

[Claims] 1 The power branched from the input shaft S ₁ that receives power from the prime mover E is transmitted to the traveling device via the gear transmission mechanism 1, and another power branched from the input shaft S ₁ is transmitted to the PTO shaft 12. In addition, a clutch 2 that is turned on and off during a gear shifting operation of the gear shifting mechanism 1 to enable the gear shifting operation of the gear shifting mechanism 1 is arranged on the downstream side of the transmission of the gear shifting mechanism 1. Drive structure of work vehicle.