JPS6230938B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a traveling transmission transmission transmission mechanism for controlling a change in vehicle speed, which is installed on a tractor mainly used for intensive work, and more specifically, a hydraulic transmission transmission transmission transmission mechanism for changing and controlling the vehicle speed by selectively operating a plurality of hydraulic clutches. The present invention relates to a traveling transmission transmission equipped with a clutch type transmission.

PRIOR TECHNOLOGY Tractors equipped with a front loader or a backhoe and used primarily for earth construction work have a transmission transmission mechanism on each side so that the left and right wheels or crawlers can be driven in opposite directions to turn the vehicle in small turns. Although a separate output shaft is provided, it is already known that such a traveling transmission transmission is equipped with a hydraulic clutch type transmission that allows easy transmission operation.
For example, Japanese Patent Application Laid-open No. 47-21834 and U.S. Patent No.
No. 3,831,690.

This type of travel transmission transmission transmission system distributes and transmits power from the input shaft to the left and right output shafts, so it has a large number of transmission shafts, and the left and right transmission systems are equipped with separate multiple hydraulic clutches, so the hydraulic There are many clutches. For the vehicle to run, two hydraulic clutches, one for each of the left and right transmission systems, are operated simultaneously. Two intermediate gears for selectively imparting backward rotation to the left and right output shafts are inserted as disclosed in Japanese Patent Laid-Open No. 47-21834, and are mounted on two intermediate shafts parallel to the output shafts. It may be fixedly installed, or it may be constructed using gears to selectively impart forward rotation to the left and right output shafts, as disclosed in U.S. Pat. No. 3,831,690.

A traveling transmission transmission transmission mechanism of a tractor mainly used for intensive work has a single output shaft, and generally a differential device receives input transmission from the output shaft and distributes it to left and right transmission systems. Therefore, when such a traveling transmission transmission is to be constructed with a hydraulic clutch type transmission, it is necessary to use the hydraulic clutch type as well as the well-known hydraulic clutch type reversing machine installed in the propulsion system of a small boat. The transmission is configured to change gears by selectively operating multiple hydraulic clutches. Such a hydraulic clutch type transmission can be disposed between two parallel transmission shafts, and is equipped with a number of hydraulic clutches corresponding to the number of gears. The transmission gear unit for the reverse gear in the hydraulic clutch type transmission includes an intermediate gear for rotating the driven-side transmission shaft in the direction in which the vehicle moves backward.

By the way, conventionally, a transmission device that performs multi-stage gear shifting, including selective reverse gear shifting, between two parallel transmission shafts in a tractor has conventionally changed gears by selectively meshing a shift gear with a mating gear. Gear-shift type with a unit of multiple-speed gears operated in unison, or constant mesh multiple-speed with single free-wheeling gears selectively connected to the transmission shaft by a shift collar. Mechanical transmissions have been constructed, such as a color shift type equipped with a gear unit, and a hydraulic clutch type transmission with the above-mentioned structure has not yet been put into practical use.

Problems to be Solved by the Invention The reason why the above configuration has not yet been put to practical use as a hydraulic clutch type transmission that allows easy and light gear shifting by operating valves without disengaging the main clutch immediately after the engine is as follows. It is determined that the

In other words, such a hydraulic clutch type transmission is equipped with multiple hydraulic clutches, one for each transmission gear unit, in addition to a transmission shaft and multiple transmission gear units, and is extremely difficult to assemble in a narrow transmission case. Therefore, it is necessary to assemble the transmission gear and hydraulic clutch so as to mount them on the transmission shaft outside the transmission case, and then incorporate them into the transmission case. In this case, the problem is how to support the intermediate gear of the reverse gear unit in a manner that allows assembly outside the transmission case. In other words, when an extra intermediate shaft parallel to the two transmission shafts is provided following the method of Japanese Patent Application Laid-Open No. 47-21834, and the intermediate gear is installed on the intermediate shaft, the number of transmission shafts increases. Undesirable. Furthermore, a structure in which a forward gear is used as the intermediate gear as in the above-mentioned U.S. Patent No. 3831690 has two
It cannot be used with a hydraulic clutch type transmission that performs variable speed transmission between transmission shafts. If the intermediate gear is installed on a cantilevered support shaft that penetrates into the inside of the transmission case, the support shaft will become long and the support of the support shaft and the intermediate gear on it will become unstable. However, if a support wall portion for supporting the inner end side of such a support shaft is provided protruding from the inner surface of the transmission case, it will interfere with the installation of the hydraulic clutch type transmission.

This invention has a structure equipped with a hydraulic clutch type transmission that changes gears by selectively operating multiple hydraulic clutches, and allows the hydraulic clutch type transmission to be easily assembled outside the transmission case, while increasing the number of shafts. The object of the present invention is to provide a new traveling transmission transmission transmission for a tractor, which solves problems such as difficulty in assembling the transmission into the transmission case and unstable support of the intermediate gear of the reverse transmission gear unit. be.

Technical Means Taken to Solve the Problems In order to solve the above-mentioned problems of the invention, the present invention provides a traveling transmission transmission transmission mechanism for a tractor, in which two transmission shafts C, C, and C, which extend along the longitudinal direction of the machine body, are installed in the transmission case A.
Multiple hydraulic clutches 70, 70', 70a,
A hydraulic clutch type transmission F that changes gears by alternative operation of the transmission gear 70a' is equipped with a single reverse gear change gear unit 40a, 6 provided in the transmission F.
5 and 62a are installed at one end side of the transmission case A when viewed in the longitudinal direction of the machine, and the hydraulic clutch type transmission is installed on the transmission case end wall 17 located on the transmission gear unit 40a, 65, 62a side. Opening 1 that allows installation of device F
8 and also closes the opening 18.
is superimposed on the end wall 17 and mounted on the outer surface of the end wall 17, one end of the two transmission shafts C and D described above are supported by the cover plate B, and the transmission gear units 40a, 65, 62a are are arranged facing into the opening 18, and the transmission gear units 40a,
A technical means is provided in which the support shaft 64 for the intermediate idle gear 65 in the intermediate gears 65 and 62a is supported by the cover plate B in a cantilever manner.

According to the present invention, two transmissions on the driving side and the driven side of the hydraulic clutch type transmission F are attached to the cover plate B that closes the opening 18 formed in the end wall 17 at one end in the longitudinal direction of the transmission case A. A single reverse gear change gear unit 40a, 6 supporting one end of the shafts C, D and provided in the hydraulic clutch type transmission F.
The support shaft 64 for the intermediate idle gear 65 in 5 and 62a is supported, and the opening 18 in the end wall 17 allows the hydraulic clutch type transmission F to be incorporated into the transmission case A. Considering that the transmission case A is formed to have a multi-speed gear unit and a hydraulic clutch mounted outside the transmission case A, two transmission shafts each having one end supported by the cover plate B are provided. C,D
The above-mentioned idle gear 65 was similarly mounted on the support shaft 64 supported by the outer plate B, and the external assembly of the hydraulic clutch type transmission F was performed. The hydraulic clutch type transmission F is assembled into the transmission case A through the opening 18 of the transmission case end wall 17, and the other ends of the two transmission shafts C and D are connected to the other end of the transmission case A in the longitudinal direction. It can be mounted on a tractor by supporting it on the side end wall or support wall.

Hydraulic clutch type transmission F which is externally assembled with a support shaft 64 for the idle gear 65 of the reverse gear stage
Since the support shaft 64 is not directly supported by the mission case A itself, the inner end of the support shaft is supported. There is no need to provide a supporting wall protruding from the inner surface of the transmission case A, and such a supporting wall does not interfere with the installation of the hydraulic clutch type transmission. However, according to the present invention, the transmission gear units 40a, 65, and 62a of the reverse gear stage are arranged so as to face the opening 18 of the transmission case end wall 17, and are cantilever-supported by the cover plate 18. Since it is sufficient that the support shaft 64 supporting the intermediate idle gear 65 in the transmission gear unit is extremely short, the support shaft 64 can be stably supported and the idle gear 65, which is the intermediate gear, can be supported stably. Support becomes stable.

Embodiment The illustrated embodiment relates to an example in which the present invention is implemented in a tractor as shown in FIG. The tractor has a pair of left and right wheels 1 and 10 at the front and rear,
An operator sits on a seat 4 on the fuselage and steers the vehicle by rotating the front wheels 1 using the steering wheel 3, and also uses the engine E at the front of the fuselage to rotate the rear wheels 10.
The machine body is composed of a clutch housing 6, a transmission case A, and a rear axle case 8 that are connected in series in the front and rear. The mechanism 5 raises and lowers the
It is configured to be driven by a PTO shaft 11.

A main clutch 13 and an input shaft 12 shown in FIGS. 2 and 3A are provided in the clutch housing 6 connected to the engine frame, and the power of the engine E is inputted via the main clutch 13. axis 1
2. The main clutch 13 is disengaged by depressing a clutch pedal 14 shown in FIG. 1 via a link interlocking body 15 shown in FIG. 3A.

To give an overview of the traveling power transmission mechanism of the illustrated tractor, as shown in Figures 2, 3A, and 4, a main shaft C is provided that passes through the transmission case A back and forth. The main shaft C is operatively connected to the input shaft 12 via a pump shaft 52 fitted with a pump gear 54 of a gear pump disposed at the rear end inside the clutch housing 6. In addition to the main shaft C, a clutch shaft D, a hollow power transmission shaft 50, and a travel drive shaft G are provided along the front-rear direction in the transmission case A. Of these, the clutch shaft D and the travel drive shaft G are The hollow power transmission shafts 50 are arranged concentrically in front and behind each other, and are loosely fitted onto the rear half of the main shaft C. Inside the transmission case A, there is a hydraulic clutch type transmission F that selectively interlocks and connects a main shaft C and a clutch shaft D at an appropriate speed ratio, and a hydraulic clutch type transmission F that selectively interlocks and connects a main shaft C and a clutch shaft D at an appropriate speed ratio. Mechanical auxiliary transmissions H which are selectively interlocked and connected are arranged in front and rear, and these transmissions F and H constitute a transmission mechanism for the traveling system. The traveling drive shaft G described above is interlocked and connected to the differential gear for the left and right rear wheels 10 by the bevel gears 88 and 89 mechanism, and the left and right differential yoke shafts 91 and 91' of the differential gear are connected to the axle shaft 9 of the left and right rear wheels 10. The driving power transmission path is completed by interlocking and connecting with the gear transmission mechanism.

Hydraulic clutch type main transmission device F for the above-mentioned traveling system
A traveling transmission transmission equipped with a mechanical sub-transmission device H is constructed according to the present invention, and the traveling transmission transmission will be described below.

First, as clearly shown in FIG. 3A, the interior of the mission case A is divided into a front chamber 26 and a rear chamber 26' by an intermediate partition wall 27. The hydraulic clutch type main transmission F is located in the front chamber 26,
Further, the mechanical sub-transmission device H is located in the rear chamber 26'.
Each is provided.

The hydraulic clutch type main transmission F constructed according to the present invention has four gears 40a, 40b, 40 as shown in FIGS. 2, 3A, and 4.
c, 40d are fitted onto the main shaft C, and 4
The gears 62a, 62b, 62c, and 62d are loosely fitted to the clutch shaft D, and the gears 40a to 40 on the main shaft C are
d and the gears 62a to 62d on the clutch shaft D, the gears that control the speed change in the forward direction of the vehicle are directly connected to each other, and the gears that control the speed change in the backward direction of the vehicle are connected to the idle gear 65. The transmission gears are constructed so that four sets of transmission gear units are formed by meshing with each other indirectly through the transmission gears. That is, depending on the gears 40b and 62b, the _F1 speed change gear unit is used, depending on the gears 40c and 62c, the _F2 speed change gear unit is used, and depending on the gears 40d and 42d, the F2 speed change gear unit is used.
_F3 transmission gear unit and gears 40a, 6
5 and 62a respectively form an R speed change gear unit. Among these speed change gear units, the R speed change gear unit 40 for the reverse gear stage is
a, 65, and 62a are particularly provided at the frontmost position. Multi-plate hydraulic clutches _F1 and _F2 are arranged on each transmission gear unit on the clutch axis D.
Hydraulic clutches 70a, _F3 hydraulic clutches 70a' and R hydraulic clutches 70 are provided, and the hydraulic clutch type main transmission F is provided with these hydraulic clutches 70a, F3 hydraulic clutches 70a' and R hydraulic clutches 70.
By selectively operating 0', 70a, 70a', and 70, the main shaft C and the clutch shaft D are interlocked and connected via any one of the speed change gear units, and three speeds are set in the forward direction of the vehicle and three speeds in the reverse direction. It is configured to perform a one-speed shift in the direction. The illustrated hydraulic clutches 70', 70a, 70a', 70 are grouped into a pair having a common clutch cylinder 67, 67'. _The clutch cylinder 67' is provided with a cylinder portion 66b for the F1 hydraulic clutch 70', and a cylinder portion 66c for the _F2 hydraulic clutch 70a and a cylinder portion 66d for the _F3 hydraulic clutch.

In order to enable the above-described hydraulic clutch type main transmission F to be incorporated into the front chamber 26, the following opening 18 is provided in the center of the front wall 17 of the transmission case A. be. That is, in the illustrated case, a similar opening 16 is also provided in the center of the rear wall 6' of the clutch housing 6, but the opening 16 is shown in chain lines in FIG. 5, in which the clutch housing 6 is omitted. As shown, each of the openings 16, 18 is formed in a so-called potbell shape with large diameter circular portions at the top and bottom. Since such a pot-shaped opening 18 is provided in the front wall portion 17, the gears 40a-40d are mounted on the main shaft C, and the gears 62a-6 described above are mounted on the clutch shaft D.
2d and hydraulic clutches 70, 70', 70a, 7
0a' is installed, the hydraulic clutch type main transmission F is inserted into the front chamber 26 from the front side of the transmission case A.
It is expected that it can be incorporated into the Such an opening 18 is closed by a side cover B fixedly installed between the clutch housing 6 and the transmission case H. Therefore, this side cover B also closes the opening 16 at the rear end of the clutch housing 6.

As described above, the transmission gear unit 40a for the reverse gear in the hydraulic clutch type main transmission F,
65 and 62a are located at the frontmost position,
The idle gear 65 is particularly supported using the side cover B mentioned above. That is, as shown in FIG. 3A, an idle shaft 64 that freely supports the idle gear 65 is supported by the side cover B in a cantilevered manner. In particular, the gears 40a, 65, 62a constituting the R transmission gear unit are
As shown in FIG. Therefore, the idle gear 65 is stably supported.

Next, the mechanical sub-transmission device H provided in the illustrated traveling transmission transmission will be explained.
As shown in FIGS. 2 and 3A, the sub-transmission device H has four gears 51 on the hollow transmission shaft 50 described above.
a, 51b, 51c, and 51d are integrally formed, and the frontmost large diameter gear 51a is meshed with the small diameter gear 80 integrally formed on the rear end of the clutch shaft D, thereby driving the transmission shaft 50. It is configured to be connected to the clutch shaft D in a deceleration-interlocking manner. A shift gear 84 and another shift gear 84' formed as a two-stage gear are fitted onto the traveling drive shaft G by splines 83, and between the clutch shaft D and the traveling drive shaft G. A dog clutch 85 is provided which can be engaged by displacing the shift gear 84 in the forward direction. As described above, the mechanical sub-transmission device H selectively slides and displaces each shift gear 84, 84' on the traveling drive shaft G, and meshes with the gear on the larger diameter side of the shift gear 84' with respect to the gear 51d. The gear ratio is 1st gear, and when the small diameter gear of the shift gear 84' is engaged with the gear 51c, the gear ratio is 2nd gear, and when the shift gear 84 is engaged with gear 51b, the gear ratio is 3rd gear. When the dog clutch 85 is inserted and the traveling drive shaft G is directly connected to the clutch shaft D, the clutch shaft D and the traveling drive shaft G are selectively interlocked and connected at a four-speed gear ratio.

As mentioned above, in addition to the above-mentioned hydraulic clutch type main transmission F, there is provided a mechanical sub-transmission H that performs four-speed gear shifting by selectively displacing the shift gears 84 and 84'. Therefore, the traveling transmission transmission shown in the figure has a total of 16 gears, 12 forward gears and 4 reverse gears, by combining both transmissions F and H, but the mechanical sub-transmission H
In order to assemble it into the rear chamber 26', an opening 24 is formed at the rear end of the mission case A as shown in FIG. 3A.
is provided. The mechanical sub-transmission device H is installed into the rear chamber 26' from the rear side of the transmission case A through the opening 24, and the opening 24 is also connected to the transmission case 26' as shown in FIG. 3A. The rear axle case 8 is closed by a front wall 25 of the rear axle case 8, which is a case following the front case A.

and an opening 18 at the front end of the mission case A.
and the partition wall 2 that partitions the inside of the mission case A into a front chamber 26 and a rear chamber 26'.
7 and the front wall portion 25 that closes the opening 24 at the rear end of the mission case A are utilized as follows.

That is, as shown in FIG. 3A and FIG. Front end is bearing 2
0', and are supported by the side lids B, respectively.
Bearings 3 are also placed on the partition wall 27 in two positions, upper and lower.
0 and 30' are fitted, and the middle part of the main shaft C is supported by the partition wall 27 through a bearing 30, and the rear end part of the clutch shaft D is supported by the partition wall 27 through a bearing 30'. Furthermore, bearings 33 and 33' are fitted to the front wall portion 25 at two positions, upper and lower, and the main shaft C
The rear end portion is supported by the front wall portion 25 via a bearing 33, and the rear end portion of the traveling drive shaft G is supported via a bearing 33'. The hollow transmission shaft 50 is placed in the rear chamber 26' and supported by the main shaft C, and is thus installed on the main shaft C.
The hollow power transmission shaft 50 supported by the main shaft C supported by the partition wall 27 and the front wall portion 25 is
It is supported by the side lid B, the partition wall 27, and the front wall portion 25 via the main shaft C. In the case shown in the figure, the main shaft C is connected to the PTO shaft 11 as described later.
Since the power is transmitted in the direction, the main shaft C is passed through the rear chamber 26' and extends into the rear axle case 8.
In the case where the power transmission shaft is fixed to a portion thereof, a transmission shaft corresponding to the illustrated transmission shaft 50 may be directly supported by the partition wall 27 and the front wall portion 25. The front end of the traveling drive shaft G is connected to the side cover B.
A support hole is formed as shown in the rear end of the clutch shaft D supported by the partition wall 27 and the clutch shaft D, and the clutch shaft D is supported at the rear end by protruding into the support hole.

The details and other parts of the illustrated traveling transmission transmission mechanism will be explained below.

First, each of the above-mentioned hydraulic clutches 70, 70', 7
0a and 70a' are the aforementioned clutch cylinders 67 and 67' that are fitted onto the clutch shaft D using keys 68 and 68', as shown in FIGS. 3A and 4.
Each cylinder part 66a, 66b, 66c, 66d
and each of the gears 62a, 62b on the clutch shaft D,
The hub portions 62c and 62d respectively support a plurality of clutch plates so as to be slidable only along the clutch axis direction, and each of the cylinder portions 6
Pistons 69, 69', 69 biased backward by return springs in 6a, 66b, 66c, 66d
a, 69a', pistons 69, 69', 69
The clutch is constructed as a well-known multi-plate hydraulic clutch in which the clutch plates a and 69a' are moved forward by supplying pressure oil behind them, and the clutch plates are frictionally engaged and operated. Clutch shaft D and cylinder part 66a-
66d includes oil passages 72, 73, 7 for supplying and discharging hydraulic oil to the hydraulic clutches 70-70a'.
3', 74, 74' are bored.

The gear pump has its pump case 56 in the third position.
As shown in Figure A, the side cover B is attached by bolt 56'.
It is fixed to the front surface of the side wall B and is used to supply hydraulic oil to the hydraulic clutches 70-70a'. As shown in FIG. 5, on the front and rear surfaces of the side cover B, a large number of oil passages 19, 19', which are long grooves with a U-shaped cross section, are formed by bending them as appropriate. The rear axle case 8 is also used as an oil tank, and a low-pressure pipe section 39 (FIG. 3A) spanning the inside and outside of the rear axle case 8 is provided, and a low-pressure pipe 61 connected to the low-pressure pipe section 39 is connected to a fifth pipe. As shown in the figure, it is connected to a base 60 fixed to the side of the side cover B, and the inside of the base 60 is communicated with the oil inlet 58 of the pump case 56 through an oil passage 59 formed in the side cover B. .

The hydraulic oil supply/discharge control mechanism K for the hydraulic clutches 70-70a is installed on the front upper surface of the upper wall portion 21 of the transmission case A, as shown in FIG. This supply/discharge control mechanism K is a fully hydraulic clutch 7.
one hydraulic clutch 70, 70', with a neutral position for discharging hydraulic fluid from 0, 70', 70a, 70a';
A switching valve S having four operating positions for supplying hydraulic oil only to the hydraulic clutches 70a to 70a' and discharging hydraulic oil from the other hydraulic clutches, and a hydraulic clutch 70.
-70a, and a pressure regulating valve (not shown) for setting the oil pressure of lubricating oil supplied to the hydraulic clutches 70-70a. Front wall part 1 of mission case A
7 is formed with a thick wall portion 22 connected to the above-mentioned upper wall portion 21. In this thick wall portion 22, the hydraulic oil passage 99 of the supply/discharge control mechanism K and the above-mentioned side cover B are formed. The oil passage 23 connecting the oil passages 19 and 19' is formed in a bent manner. A part of the drain oil passage 99' (FIG. 5) of the supply/discharge control mechanism K is communicated with the front chamber 26 through the upper wall portion 21 of the mission case A.

As clearly shown in FIG. 4, the front end of the clutch shaft D is fitted with a transfer tube 75 which is attached to the front surface of the side cover B with bolts 76 within the clutch housing 6. Four circumferential grooves 71a, 71b, 71c, and 71d are formed on the circumferential surface of the front end of the clutch shaft D, and the transfer tube 75 seals between the circumferential grooves 71a, 71b, 71c, and 71d. Each circumferential groove 71a, 71b, 71c, 71d is connected on the one hand to a corresponding hydraulic clutch 70, 70', 70a, 70a' via the oil passage 72-74'. Also, each circumferential groove 71a, 71b, 71c, 7
1d, on the other hand, communicates with a corresponding one of the plurality of oil passages 77 (FIG. 5) formed in the transfer tube 75.

The above-mentioned large number of oil passages 1 formed in the side cover B
9 and 19' are the discharge ports 57 of the gear pump described above.
(FIG. 5) and the supply/discharge control mechanism K, and between the supply/discharge control mechanism K and the oil passage 77 (FIG. 5) of the transfer tube 75. For this purpose, the discharge port 57 is communicated with a part of the oil passages 19, 19', and as described above, the thick wall portion 22
The oil passage 23 is communicated with the oil passages 19, 19', and the oil passages 19, 19' are appropriately communicated with the oil passage 77.

Next, the operating device 100 of the mechanical sub-transmission H will be explained with reference to FIG.
The shift gears 84, 84' are moved on the travel drive shaft G by operating the shifters 87, 87' fitted in the shifter fitting grooves of these shift gears 84, 84' by the change lever 86, respectively. It is assumed that the sliding displacement is caused by
The upper wall 21 of the mission case A has a rear chamber 26'.
An opening 101 is formed at an upper position, and this opening 101 is covered by a lid 102. The change lever 86 is swingably supported by a gearbox mounted on the lid body 102 via a sphere, and the change lever 86 can be freely engaged and detached from the shifters 87 and 87' at its lower end. .

The main shaft C is also supposed to transmit power to the PTO shaft 11, and as shown in FIGS. 2 and 3 A, the PTO shaft C located on the extension line of the main shaft C
It is connected to the drive shaft 11' by a coupling 92. As shown in Figures 2 and 3,
The PTO drive shaft 11' and the PTO shaft 11 are parallel to each other, and a PTO transmission is provided between the two shafts 11' and 11. This PTO transmission has a two-stage shift gear 94 spline-fitted to the PTO drive shaft 11'.
and a three-stage gear 94 installed loosely on the PTO shaft 11.
a, and the second gear 94' installed loosely on the PTO drive shaft 11', which is the third gear 9 on the PTO shaft 11.
A two-stage gear 94' that is rotated at a reduced speed by 4a.
and the gear 94b loosely installed on the PTO shaft 11, which is the two-stage gear 94' on the PTO drive shaft 11'.
a gear 94b that is caused to rotate at a reduced speed;
A clutch metal fitting 94c is spline-fitted to the PTO shaft and constitutes a dog clutch 95a with the third gear 94a, and another dog clutch 95b with the gear 94b. 94c. Shifters 93 and 93' are engaged with the second shift gear 94 and the clutch hardware 94c, respectively, and the shifters 93 and 93' selectively slide and displace the second shift gear 94 and the clutch hardware 94c. The rotation speed of the shaft 11 can be changed in four stages. PTO drive shaft 11' and PTO
As shown in FIG.
6, 37 and 36', 37'.

In FIG. 1, reference numeral 98 is an operating lever that slides and operates the spool of the switching valve S, 98' is a part of the connection mechanism that connects the operating lever 98 and the spool of the switching valve S, and 96 is the aforementioned PTO transmission. an operating lever for slidingly operating the shifters 93, 93' of the device;
38 is a hydraulic case of the hydraulic lift mechanism 5. In FIG. 2, 90 is the Tef yoke shaft 91.
The brake provided at the end, 53 in FIGS. 3A and 4, is a coupling that connects the input shaft 12 and the pump shaft 52. In Figure 5,
M is a shifter that directly slides and displaces the spool of the switching valve S, 79 is a lubricating oil passage provided in the side cover B, and the oil passage 79 is connected to the transfer pipe 75 shown in FIG.
Through the hollow space 78 inside and the oil passage inside the clutch shaft D,
It is connected to the clutch plate portions of the hydraulic clutches 70, 70', 70a, 70a'.

The traveling transmission transmission shown in the figure is constructed as explained above, so when installing the hydraulic clutch type main transmission F into the front chamber 26 of the transmission case A, the main shaft C and the clutch must be connected. The shaft D is supported in advance by the side cover B via bearings 20, 20', and gears 40a, 40b, 40 are mounted on the main shaft C.
gears 62a, 62b, 62c, 62d and hydraulic clutches 70, 70', 70a, 70a' are installed in advance on the clutch shaft D, and the idle gear 65 of the R transmission gear unit is installed in advance. is supported by the side cover B via the idle shaft 64 and meshed with the gears 40a, 62a, and the pump case 56 and transfer tube 75 are also attached to the side cover B. It can be installed from the side into the vestibule 26 through the opening 18.
At this time, the bearing 3 to be held on the partition wall 27
0 and 30' are installed in advance at predetermined positions on the main shaft C and the clutch shaft D, so that they can be fitted into corresponding holes in the partition wall 27 when the main transmission F is assembled. After the above assembly, the side cover B is fixed in the illustrated position.

When the hydraulic clutch type main transmission F has been assembled into the front chamber 26 in this way, the gear 51 is inserted onto the main shaft C from the rear end opening 24 of the transmission case A.
a, 51b, 51c, and 51d are extrapolated, and then gears 84, 84' are mounted, and the traveling drive shaft G is supported on the front wall part 25 of the rear axle case via a bearing 33'. is similarly assembled into the rear chamber 26' through the opening 24, and the front end is inserted into the support hole at the end of the clutch shaft D. The bearing 33 may be installed at the position shown in the figure before the traveling drive shaft G is installed, or it may be installed at the position shown from the rear end side of the main shaft C later. This completes the installation of the mechanical sub-transmission device H into the rear chamber 26'.

When using the illustrated tractor, the traveling transmission transmission mechanism first sets the mechanical auxiliary transmission H to an appropriate gear before use, and when working in a field etc., the vehicle speed is mainly controlled by the hydraulic clutch type main transmission F. On the other hand, the main transmission F is easily shifted by operating the switching valve S without disengaging the main clutch 13, so the physical and mental fatigue of the driver is reduced. This is greatly reduced compared to the case with a type main transmission.

By arranging the hydraulic clutch type main transmission F on the front stage and the mechanical sub-transmission H on the rear stage to form a traveling transmission transmission, the hydraulic clutches 70-70a' of the main transmission F are arranged. Since the hydraulic clutches 70 to 70a' are provided on the front side of the travel drive path where the transmission torque is small, a small capacity hydraulic clutch 70-70a' can be used, and a mechanical sub-transmission device in which gears are shifted by gears 84 and 84' is used. H
However, since the gear is located in the area where the rotation speed is reduced by the main transmission F and the rotation speed of the gear is relatively low, the inertial rotation of the gear after disengaging the main clutch 13 prior to the gear shift operation is that small. Speed change operations by shifting become easier.

Effects of the Invention As already mentioned in the section on the effects of the invention, the present invention provides an opening in one end wall 17 of the transmission case A in the longitudinal direction, which allows the hydraulic clutch type transmission device F to be incorporated into the transmission case A. 18, and a cover plate B mounted on the outer surface of the end wall 17 is connected to one end of each of two transmission shafts C and D equipped with a transmission gear and a hydraulic clutch in a hydraulic clutch type transmission F. A support shaft 64 that supports the intermediate idle gear 65 in the gear unit of the reverse gear stage.
Considering the structure in which the two transmission shafts C and D and the support shaft 64 are supported by the cover plate B, the hydraulic clutch type main transmission F can be easily installed outside the transmission case A. It is assumed that it can be assembled and incorporated into the mission case A through the opening 18 of the mission case end wall 17. Since a long intermediate transmission shaft is not added between the two transmission shafts C and D to support the idle gear 65, the number of transmission shafts is not increased, and the support shaft 64 is connected to the cover plate B. The support shaft 6 is supported in a cantilever manner by
Since a support wall for 4 is not required on the inner surface of the transmission case A, it is not difficult to assemble the hydraulic clutch type transmission F into the transmission case A.

However, the present invention is particularly advantageous in that the transmission gear units 40a, 65, 62a of the reverse gear stage are not only located at one end side of the transmission case A, but also faced into the opening 18 of the end wall 17 of the transmission case. The intermediate idle gear 65 in the same unit is positioned as close as possible to the inner surface of the cover plate B on the outer surface of the case end wall 17.
Since it is sufficient that the support shaft 64 supported in a cantilever manner is extremely short, the support shaft 64, and therefore the intermediate idle gear 65 thereon, can be supported extremely stably.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted external side view of a tractor equipped with an embodiment of the present invention, Fig. 2 is a schematic diagram of the entire power transmission device, and Fig. 3A is a main transmission and sub-transmission of the power transmission device. Fig. 3B is a detailed internal sectional view of the PTO section, Fig. 4 is an enlarged sectional view of the main transmission section, and Fig. 5 is a partially omitted sectional view taken along line - in Fig. 3A. It is. A...Mission case, B...Side cover, C...Main shaft,
D...Clutch shaft, E...Engine, F...Hydraulic clutch type main transmission, G...Travel drive shaft, H...Mechanical sub-transmission, 6...Clutch housing, 17...Front wall, 18...Opening, 20, 20'...Bearing,
24... Opening, 25... Front wall, 26... Front chamber, 2
6'... Rear chamber, 27... Partition wall, 40a, 40b, 4
0c, 40d...Gear, 62a, 62b, 62c,
62d...Gear, 64...Idle shaft (support shaft) 65...
Idle gear, 70, 70', 70a, 70a'...
Hydraulic clutch.

Claims (1)

[Claims] 1 Multiple hydraulic clutches 70, 7 are installed between the two transmission shafts C and D along the longitudinal direction of the aircraft in the transmission case A.
0', 70a, 70a', a hydraulic clutch type transmission F that changes gears by selectively operating gears 0', 70a, 70a' is equipped with a single reverse gear change gear unit 40a, 65, 62a installed in the front and rear of the aircraft. The transmission gear unit 40a, 65,
An opening 18 is formed in the transmission case end wall 17 located on the side 62a, and a lid plate B that closes the opening 18 is superimposed on the end wall 17. The end wall 1
7 on the outer surface of the 2 transmission shafts C and D described above.
One end is supported by the cover plate B, and the speed change gear units 40a, 65, 62a are arranged to face inside the opening 18, so that the intermediate idle gear in the speed change gear units 40a, 65, 62a is 65 is supported in a cantilever manner by the cover plate B.