JPH0249139Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an improvement of a transmission mechanism in a tractor.

<Prior art> A dry double clutch is attached to the flywheel of the engine mounted on the tractor body, and the input main shaft that receives rotational power from the engine is set in a so-called double-shaft type, inside and outside.
The outer hollow shaft participates in the generation of the propulsion system transmission mechanism, while the inner solid shaft is used for the traction work machine.
As a PTO drive shaft, it is extended into the final transmission case at the rear of the aircraft, and the PTO transmission gear group on the extended shaft,
By selectively meshing this with a group of PTO speed change gears on a PTO shaft arranged in parallel, rotational driving force for a work machine at a predetermined gear ratio (hereinafter referred to as
It is abbreviated as PTO. ) transmission mechanisms are known.

<Problem that the invention seeks to solve> However, since the rotational driving force is now intermittent by a mechanical dry double clutch, for example, in a front loader, only the clutch of the drive system is used. When used frequently for heavy-duty work that requires repeated intermittent rotational power, the heat absorption capacity due to frictional heat dissipation and slippage when the clutch is half-clutched is insufficient compared to the single clutch specification.
Accidents that result in loss of transmission due to burnout are likely to occur.

If, for example, a ventilation hole is formed in order to dissipate the frictional heat, foreign matter such as dust may enter through the ventilation hole and get caught in the clutch disk. Furthermore, since it is a mechanical clutch, there is a problem in that its operating system is mechanically complex.

<Means for solving the problems> In order to solve these problems, the present invention
Its structure consists of a PTO drive shaft that constantly receives rotational power from the engine, and a hollow input main shaft that intermittently receives rotational power from the engine using a dry single clutch. The rear part of the PTO system drive shaft facing inside the final transmission case is located on the axis of rotation of the shaft.
It is defined as a system extension drive shaft, bearing the shaft on the rear wall and intermediate partition wall that are integrally formed on the final transmission case itself, and the PTO shafts are arranged in parallel in a similar bearing position directly below the rear wall and the intermediate partition wall. At the same time, a PTO transmission gear group spline-fitted on the PTO shaft and a PTO transmission gear group fixed on the extended drive shaft form a PTO transmission mechanism that can selectively mesh with each other. In a tractor, in particular, the above-mentioned PTO system extension drive shaft has a PTO input shaft whose rear end is bearing on the intermediate partition wall of the final transmission case, and a rear end whose rear end is also bearing on the rear wall of the final transmission case. and equipped with the above transmission gear group.
Separately formed as a front and rear pair with the PTO transmission gear shaft,
A hydraulic multi-plate clutch is installed between the divided parts to connect and disconnect the power transmission of both shafts, and the supply and discharge of hydraulic oil to and from the clutch can be switched and controlled by a hand switch on the cockpit. It is characterized by:

<Example> Hereinafter, the specific configuration of the present invention will be described in detail based on the illustrated example. In FIGS. 1 and 2 showing the entire transmission mechanism of the tractor,
10 is an engine mounted on the front part of the tractor body, 11 is its crankshaft, and a flywheel 12 that rotates together with this crankshaft faces inside the clutch case M1. A is a dry single clutch attached to the flywheel 12, so that the rotational power of the engine 10 is intermittently transmitted from the flywheel 12 to the input main shaft 13.

As is clear from the figure, the input main shaft 13 has a hollow shaft shape, and is installed horizontally on the rotational axis of the crankshaft 11.
The middle part is the intermediate partition wall 1 of the clutch case M1.
4, the rear end portions are respectively bearing on the rear wall 15 of the case M1. Reference characters a and b indicate a front clutch chamber and a rear main transmission gear chamber, which are defined within the clutch case M1 by the intermediate partition wall 14.

M2 is a transmission case connected to the rear part of clutch case M1, and its interior is divided into two by an intermediate partition wall 16 into a preliminary chamber c on the front side and an auxiliary transmission gear chamber e on the rear side. Further, a final transmission case M3 is connected to the rear end of the transmission case M2, and an intermediate partition wall 17 divides the inside of the final transmission case M3 into a differential gear chamber f on the front side and a PTO transmission gear chamber on the rear side. It is divided into two parts.

18 and 19 are the transmission case M
2 and the rear wall of final transmission case M3, but neither of them is equipped with a separate opening/closing lid.
The cases M2 and M3 are formed in advance in a continuous and integral manner. The transmission case M2
In particular, the upper wall surface of the preliminary chamber c is finished as a flat deck surface 20 as a whole, while the upper wall surface of the final transmission case M3 is opened, and a working machine (not shown) that is fixed to this lifts and lowers. The lid is closed from above by a hydraulic cylinder unit.

Reference numeral 21 is a general term for a PTO drive shaft, which is composed of a front drive shaft 21a, an intermediate drive shaft 21b, and a rear extension drive shaft 21c, which are directly connected to each other and rotate integrally. The front drive shaft 21a passes through the hollow interior of the input main shaft 13 and is spline-fitted to the flywheel 12, so that the rotational power of the engine 10 is constantly received. Further, an intermediate drive shaft 21b following the front drive shaft 21a faces into the transmission case M2, and an extended drive shaft 21c at the rear.
faces into the final transmission case M3, and its midway portion is the intermediate partition wall 1.
7, the rear end portions are respectively bearing on the rear wall 19.

23 is a general term for the traveling system countershafts that are arranged in parallel with the input main shaft 13 and the PTO system drive shaft 21 directly below the input main shaft 13 and the PTO system drive shaft 21, and this is the main transmission system countershaft 23. Traveling transmission gear shaft 2 facing into gear chamber b
3a, a bevel pinion shaft 23b that also faces into the sub-transmission gear chamber e, and an intermediate connecting shaft 23c located between the front and rear of both shafts 23a and 23b.
From the book, the bevel pinion 24 of the bevel pinion shaft 23b is transmissionably combined as if forming one overall shaft, and the bevel pinion shaft 23b
is engaged with the differential gear 25 in the differential gear chamber f to drive the rear wheels.

B is a main transmission mechanism, which is composed of a main transmission gear group fixedly installed on the input main shaft 13, and a main transmission gear group loosely fitted on the running transmission gear shaft 23a so as to constantly mesh with the main transmission gear group, A predetermined number of travel gear ratios can be obtained by sliding a switching sleeve spline-fitted onto the travel gear shaft 23a using a main shift operation lever (not shown).

26 is a hollow gear shaft that is loosely fitted in the middle of the PTO system intermediate drive shaft 21b in the sub-transmission gear chamber e, and the sub-transmission gear group carved therein and the corresponding bevel pinion shaft 23b are connected to the hollow gear shaft 26. A sub-transmission mechanism E capable of selective meshing is formed by the sub-transmission gear group. Needless to say, the slide gear spline-fitted onto the bevel pinion shaft 23b is shifted by an auxiliary shift operation lever (not shown) to obtain a traveling shift action with a required gear ratio. stomach. In addition, in the preliminary chamber c, the traveling transmission gear shaft 2
3 and the intermediate connecting shaft 23c, a forward/reverse transmission mechanism C is also inserted and installed, but a detailed explanation thereof will be omitted.

The PTO system rear extension drive shaft 21c that I mentioned earlier is as shown in the enlarged view of Figure 3.
The front PTO input shaft 22a facing substantially into the differential gear chamber f and the rear PTO transmission gear shaft 22b located within the PTO transmission gear chamber g are formed as a pair. Directly below, PTO output shafts 27 (simply referred to as PTO shafts) are arranged in parallel. The PTO axis 2
7 is of course projected out of the aircraft from the rear wall 19 of the final transmission case M3.

And PTO transmission gear groups 28, 29, 30, and 31 fixedly installed on the PTO transmission gear shaft 22b,
The PTO transmission gears 32 and 33 groups spline-fitted onto the PTO shaft 27 form a PTO transmission mechanism G that can selectively mesh with each other. the
By sliding the transmission gear groups 32 and 33 on the PTO shaft 27 in the longitudinal direction using a PTO transmission operating lever (not shown), a PTO transmission ratio of a predetermined number of stages can be obtained.

In that case, among the transmission gear groups 28, 29, 30, and 31 carved on the PTO transmission gear shaft 22b,
The diameter dimension d1 of the largest gear 31 is smaller in advance than the opening dimension s of the bearing hole 34 for the PTO gear shaft correspondingly opened in the rear wall 19 of the final transmission case M3 itself. , and the PTO gear shaft 22
b to its final transmission case M
3 from the rear outside into the PTO transmission gear chamber g, so to speak, it can be inserted straightly without any hindrance.

Furthermore, H is a PTO input shaft 22a forming the above-mentioned extended drive shaft 21c and a PTO transmission gear shaft 2.
It is a general term for a hydraulic multi-disc clutch that is installed interveningly in the divided part from the PTO system drive shaft 21, and acts intermittently on the rotational power transmitted from the front drive shaft 21a and the intermediate drive shaft 21b of the PTO system drive shaft 21.

That is, near the rear end of the front PTO input shaft 22a, the rear end protrudes as a circular flange 35 branching into a bifurcated cross section, where it is bearingly supported by the intermediate partition wall 17 of the final transmission case M3. and PTO
It faces into the transmission gear chamber g.

Reference numeral 36 indicates a plurality of disk plates that are fitted onto the outer circumferential surface of the flange 35 so as to be integrally rotatable and slidable in the front-rear direction, and 37 is a corresponding mating plate that can be brought into frictional contact. It is similarly fitted into the opening of the U-shaped clutch case 38 and is prevented from coming off by a cover plate 39 fixed to the opening. In that case, the diameter d2 of the clutch case 38 is set to be considerably larger than the opening size s of the bearing hole 34 described above.

The boss portion of the clutch case 38 is spline-fitted to the vicinity of the front end of the PTO transmission gear shaft 22b so that it can rotate integrally with the front end of the PTO transmission gear shaft 22b and the PTO input shaft 22.
The vicinity of the rear end of a is in a loosely fitted relationship with the needle bearing 40 interposed therebetween. Reference numeral 41 denotes a piston enclosed in the clutch case 38, which receives hydraulic oil into its cylinder 42 and moves the disc plate 36 and the mating plate 3.
7. 43 is a return spring for the piston 41, 44 is a retainer for the spring 43, 45 is a retaining ring for the shaft, and 46 is an oil seal.

Further, reference numeral 47 denotes a hydraulic oil supply passage bored along the longitudinal center line of the PTO gear shaft 22b, the front end of which is connected to the cylinder 42 via a communication passage 48 provided in the clutch case 38.
While opening inward, the rear end inlet also communicates with an inlet passage 50 bored in the cover block 49. The cover block 49 is fixed to the rear wall 19 of the final transmission case M3 so as to cover the bearing hole 34.

The supply and discharge control of the hydraulic oil is performed by a hydraulic circuit as shown in FIG.

In the circuit diagram, 51 is an oil tank formed using the inside of transmission cases M2 and M3;
2 is an oil pump driven by the engine 10, 5
3 is a relief valve, and 54 is a solenoid valve, which can be turned on and off by a hand switch 55 disposed above the cockpit of the aircraft to control the hydraulic multi-disc clutch H intermittently. ing.

<Operation> According to the above configuration, the dry single clutch A attached to the flywheel 12 of the engine 10
It goes without saying that the traveling transmission system can be operated intermittently, but in order to constantly receive the rotational power of the engine 10, the flywheel 12 is separately and independently of the input main shaft 13 that forms the main transmission mechanism B of the traveling system. The directly connected PTO drive shaft 21, especially the rear extension drive shaft 21c, is connected to the final transmission case M.
3, the PTO input shaft 22a and the PTO speed change gear shaft 22b are divided into a pair of front and rear parts.
PTO transmission gear 28 on PTO transmission gear shaft 22b,
Parallel to the 29th, 30th, 31st groups and the position directly below them
The PTO transmission gears 32 and 33 groups on the PTO shaft 27 form a PTO transmission mechanism G that can selectively mesh with each other, and a hydraulic multi-disc clutch H is interposed in the divided portion. For,
Separately and independently from the travel transmission system, only the PTO transmission system can be turned on and off using the switch 55 on the cockpit.

Moreover, the PTO transmission mechanism G and its transmission gear shaft 2
2b and the hydraulic clutch H are all housed together in the PTO transmission gear chamber g of the final transmission case M3, so the design can be significantly streamlined and simplified.
It is especially useful for assembling, disassembling, maintaining, and inspecting only the PTO transmission system.

That is, in terms of assembly and disassembly, as described above, the diameter dimension d1 of the largest gear 31 on the PTO transmission gear shaft 22b corresponds to the transmission gear shaft formed with an opening in the rear wall 19 of the final transmission case M3 itself. As suggested from FIG. 5, the diameter dimension d2 of the clutch case 38 is determined to be smaller than the opening dimension s of the receiving hole 34, and the diameter dimension d2 of the clutch case 38 is determined to be larger than the opening diameter dimension s. , the hydraulic multi-disc clutch H is set in advance.
After fitting and setting the PTO input shaft 22a to the rear end flange 35, insert it from the top opening of the PTO transmission gear chamber g into the intermediate partition wall 17 as shown by arrow Y, and connect the PTO input shaft 22a to the PTO system. Especially the intermediate drive shaft 2 of the drive shaft 21
1b, and then the PTO transmission gear shaft 2.
2b to final transmission case M3
It can be assembled so that it can rotate integrally with the clutch H by inserting it straight from behind as shown by the arrow X through the bearing hole 34 of the rear wall 19. After that, it goes without saying that the cover block 49 is attached and fixed, and by performing the above operations in the opposite direction, the disassembly work can be carried out with high efficiency.

<Effects of the Invention> As described above, the present invention includes a PTO drive shaft 21 that constantly receives rotational power from the engine 10, and a hollow input main that intermittently receives rotational power from the engine 10 using a dry single clutch A. The shaft 13 and the crankshaft 11 have a so-called internal and external dual shaft configuration.
The rear part of the PTO drive shaft 21 facing into the final transmission case M3 is defined as a PTO extension drive shaft 21c, which is integrally formed with the final transmission case M3 itself. PTO shafts 27 are arranged parallel to each other in the same bearing condition directly below the rear wall 19 and intermediate partition wall 17, and a PTO gearbox is spline-fitted onto the PTO shafts 27. In a tractor in which a PTO transmission mechanism G is formed by gear groups 32 and 33 and PTO transmission gear groups 28, 29, 30, and 31 fixedly installed on the extended drive shaft 21c, which can selectively mesh with each other. Especially the PTO type extension drive shaft 21c mentioned above.
, the rear end of which is bearing on the intermediate partition wall 17 of the final transmission case M3.
The rear end of the PTO input shaft 22a is similarly supported on the rear wall 19 of the transmission case M3, and the transmission gears 28, 29, 30, and 31 groups are provided.
The PTO transmission gear shaft 22b is formed as a front and rear pair, and a hydraulic multi-plate clutch H is interposed in the divided portion to connect and disconnect the transmission operation of both shafts 22a and 22b, and the hydraulic oil is supplied to the clutch H. Since the evacuation function can be switched and controlled by a hand switch 55 on the cockpit, there is an effect that the problems of the prior art mentioned at the beginning can be easily solved.

That is, since the rotational power of the drive system is intermittent by the dry single clutch A, the tractor can be started extremely smoothly based on the so-called half-clutch operation, and its heat dissipation effect is also efficient. This has been well achieved and there is no risk of causing a burnout accident.

On the other hand, the rotational power of the PTO system is connected and disconnected by a separate hydraulic multi-plate clutch H, and the supply and discharge of hydraulic oil to this clutch is also controlled by a hand switch 55 on the cockpit. Because of this, the intermittent action is reliably achieved,
Not only can heavy tasks such as front loaders be carried out with ease and peace of mind, but durability and reliability can also be significantly improved.

In particular, as explained based on the illustrated embodiment,
The front PTO input shaft 22a that forms the PTO system rear extension drive shaft 21c and the rear PTO transmission gear shaft 22b are connected to the intermediate partition wall 17 and rear wall 19 of the final transmission case M3 itself.
When bearing the gear, the diameter d1 of the largest gear 31 fixed on the PTO transmission gear shaft 22b is set to be larger than the opening diameter s of the transmission gear shaft bearing hole 34 formed in the rear wall 19. With the hydraulic multi-plate clutch H attached to the rear end of the PTO input shaft 22a, first insert the PTO input shaft 22a into the intermediate partition wall 17 as shown by arrow Y in FIG. After that, insert the PTO transmission gear shaft 22b from its bearing hole 34 as shown by the arrow 19, in addition to the above-mentioned effects, the PTO system transmission mechanism parts are collectively housed in the PTO transmission gear chamber g of the final transmission case M3, and the Not only can various operations such as assembly/disassembly, maintenance, and inspection be performed with high efficiency, but the design can also be simplified and rationalized, which can be said to be even more profitable.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional schematic diagram showing the overall transmission system of the tractor according to the present invention, Figure 2 is a side sectional view of the transmission mechanism, and Figure 3 is an extraction of the main parts of the present invention from Figure 2. FIG. 4 is a hydraulic circuit diagram showing a hydraulic oil supply/discharge control system, and FIG. 5 is an explanatory diagram corresponding to FIG. 3 showing a method of assembling a PTO system extended drive shaft. 10... Engine, 11... Crankshaft, 13... Input main shaft, 14, 16,
17... Intermediate partition wall, 15, 18, 19... Rear wall, 21... PTO drive shaft, 21a
...Front drive shaft, 21b...Intermediate drive shaft, 21c...Extension drive shaft, 22a...PTO input shaft, 22b...PTO transmission gear shaft, 23...Traveling system countershaft,
27...PTO (output) axis, 28-33...PTO
Transmission gear, 34...Bearing hole, 55...Switch, A...Single clutch, B...Main transmission mechanism, C...Forward/reverse transmission mechanism, E...Sub-transmission mechanism, G...PTO transmission mechanism, H...Multi-plate clutch,
M1...Clutch case, M2...Transmission case, M3...Final transmission case.

Claims (1)

[Claims for Utility Model Registration] 1. A PTO drive shaft 21 that constantly receives rotational power from the engine 10, and a hollow input main shaft 13 that intermittently receives rotational power from the engine 10 using a dry single clutch A. , is arranged on the rotational axis of the crankshaft 11 as a so-called double shaft type inside and outside, and the rear part of the PTO drive shaft 21 facing into the final transmission case M3 is defined as a PTO extension drive shaft 21c. , the PTO shafts 27 are arranged parallel to each other in a similar bearing state directly below the rear wall 19 and the intermediate partition wall 17, which are integrally formed on the final transmission case M3 itself, A spline is fitted onto the PTO shaft 27.
A tractor in which PTO transmission gear groups 32 and 33 and PTO transmission gear groups 28, 29, 30, and 31 fixedly installed on the extension drive shaft 21c form a PTO transmission mechanism G that can selectively mesh with each other. - in which the rear end of the extended drive shaft 21c is a final transmission case M;
A PTO input shaft 22a bearing on the intermediate partition wall 17 of transmission case M3, and a rear end bearing on the rear wall 19 of transmission case M3, and equipped with the above-mentioned transmission gear groups 28, 29, 30, and 31.
The transmission gear shaft 22b is divided into a front and rear pair, and a hydraulic multi-disc clutch H is interposed in the divided portion to connect and disconnect transmission of the shafts 22a and 22b, and hydraulic oil is supplied and discharged to and from the clutch H. A transmission mechanism for a tractor, characterized in that the action can be switched and controlled by a hand switch 55 on the driver's seat. 2 The diameter dimension d1 of the largest gear 31 fixedly installed on the PTO transmission gear shaft 22b is the opening dimension of the bearing hole 34 for the PTO transmission gear shaft formed in the rear wall 19 of the final transmission case M3 itself. Claim 1 for utility model registration characterized by having dimensions smaller than S
Tractor transmission mechanism as described in Section 1.