JPS6339446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a running power transmission device that controls the speed change of running power in an agricultural tractor that is attached with various working machines and used for various agricultural works.
It is related to

Agricultural tractors are generally constructed with a clutch housing containing the main clutch and a transmission case containing the variable speed transmission mechanism arranged in series at the front end of the tractor. While it is commonly used to install speed change transmission mechanisms such as driving power transmissions, clutch housings only have the main clutch installed in their front end, and more than half of the interior is simply connected from the main clutch to the clutch housing. It is a dead space with only a single transmission shaft that transmits power into the transmission case.

In other words, there is a known example (Japanese Utility Model Publication No. 51-27532) in which an auxiliary transmission box is installed in the middle part of the clutch housing, but it is heavy and requires stable support because it controls the power transmission. When a clutch housing is used to support a speed change transmission mechanism, the clutch housing is made of sheet metal as disclosed in Japanese Utility Model Publication No. 53-15236, or a similarly thin and lightweight clutch housing. This is because, like the transmission case, it is necessary to form the clutch housing to have a high supporting strength, which increases the weight ratio and cost of the tractor.

However, if part of the speed change transmission mechanism, which has conventionally been installed inside the transmission case, can be incorporated into the dead space inside the lightweight clutch housing, the longitudinal length of the tractor body can be reduced accordingly, improving the machine turning performance and improving the machine body. This will provide practical benefits such as weight reduction.

In view of this, this invention allows a portion of the traveling power transmission device, which occupies a large longitudinal length within the fuselage, to be incorporated into the clutch housing, which can be made as lightweight as before, thereby shortening the longitudinal length of the fuselage. It is an object of the present invention to provide a novel traveling power transmission device for an agricultural tractor, which is designed to be easily incorporated into the agricultural tractor.

To this end, the present invention takes the following technical measures in an agricultural tractor in which a clutch housing containing a main clutch and a transmission case containing a transmission mechanism are arranged in series in the front end. Ta.

That is, as clearly illustrated in FIG. 5, the bearing plate 36, which is connected and supported to the mission case 4 via a plurality of connecting portions 36a extending rearward from the rear peripheral end portion, is attached to the mission case 4. 4 in the clutch housing 2 with a space in the front-rear direction. In the illustrated example, four connecting portions 36a of the bearing plate 36 described above are provided as shown by broken lines in FIG. 4.

As illustrated in FIG. 3, a plurality of transmission shafts 8, 16, 17 extending in the front and back direction are connected to the bearing plate 36 and the supporting wall portion 4 on the inner surface of the transmission case.
a, 4b, and 4d, and the following configuration is adopted regarding the arrangement of the transmission members of the traveling power transmission devices 10, 12.

That is, as shown in FIG. 3, some of the speed change gears 19, 21, 23 of the speed change gears and clutches that are installed on the plurality of transmission shafts 8, 16, 17 and change the speed of the traveling power. and clutches 25, 27 are disposed within the clutch housing 2. In the illustrated example, the traveling power transmission is constructed by arranging a hydraulic clutch type transmission 10 as a main transmission and a mechanical transmission 12 as an auxiliary transmission and connecting them in series. Three transmission gears 19, 21, 23 and two hydraulic clutches 25, 27 of the hydraulic clutch transmission 10 are arranged on the transmission shafts 8, 16, 17 in the housing 2. The intermediate gear 23A for the reverse gear in the hydraulic clutch type transmission 10 is also supported by the bearing plate 36 and disposed within the clutch housing 2.

Assemble the traveling power transmission devices 10, 12 to the transmission case 4, the bearing plate 36, and the transmission shafts 8, 16, 1.
7 and the transmission gear 1 on the transmission shaft part.
9, 21, 23 and the clutches 25, 27 are assembled with them protruding outside the transmission case 4, and then the bearing plate 36 is inserted into the clutch housing 2 from the rear end side of the housing 2. This is done to secure the clutch housing 2 and transmission case 4 together.

To explain the embodiment, as shown in FIG. 1, an engine 1 is mounted on the front of the fuselage, and the power of the engine 1 is transferred to a clutch housing 2 in which a main clutch 3 is housed within a large diameter portion 2a at the front end. The transmission is transmitted through a transmission case 4 containing a transmission mechanism (to be described later), and then into a rear housing 5 that constitutes the rearmost part of the aircraft, and drives the left and right rear wheels 6 to cause the aircraft to travel. At the same time, the PTO for driving the work equipment extends to the rear of the machine.
In an agricultural tractor configured to rotate the shaft 7, the present invention is implemented as follows.

That is, as shown in FIG. 2, the running power transmission mechanism of the illustrated agricultural tractor includes a drive shaft 8 that is interlocked and connected to the engine 1 via the main clutch 3 and extends along the longitudinal direction of the machine. , a hollow transmission shaft 9 is loosely fitted in the middle of the drive shaft 8, and the drive shaft 8 and the hollow transmission shaft 9 are selectively interlocked and connected at an appropriate speed ratio. A hydraulic clutch type transmission 10, which is a transmission, is provided between the hollow transmission shaft 9 and a transmission shaft 11 provided parallel thereto, with an appropriate transmission ratio between the two shafts 9 and 11. A mechanical transmission 12 is provided as a traveling power sub-transmission that is selectively interlocked and connected, and the transmission shaft 11, which constitutes the output shaft of the traveling power transmission parts 10 and 12, is connected via a bevel gear transmission mechanism 13. Differential device 1 for left and right rear wheels 6
4, and the left and right output shafts 14a of this differential device 14 are respectively connected to the left and right rear wheel axles 6a via the final gear reduction device 15,
However, as shown in FIG. 3, the hydraulic clutch type transmission 10 described above has a
It is provided with approximately half of it facing inside the clutch housing 2.

To explain more specifically, the hydraulic clutch type transmission 10, as shown in FIGS. 2, 3, and 4,
Two power shift shafts 16, 17 arranged in parallel
It is equipped with As shown in FIGS. 2 and 3, two speed change gears 18 and 19 are fixedly installed on the drive shaft 8. As shown in FIGS. And one power shift shaft 1
On the 6, there is an _F1 idler gear 20 meshed with the speed change gear 18 on the drive shaft 8, and an R intermediate gear 20 supported so as to freely rotate and meshed with the other speed change gear 19 on the drive shaft 8. R idler gear 2 meshed with gear 23A
On the other power shift shaft 17, there is an F2 idler gear 21 meshed with the speed change gear 19 on the drive shaft 8, and on the other power shift shaft 17 there is an _F2 idler gear 21 meshed with the speed change gear 19 on the drive shaft 8. The _F3 idler gear 22 meshed with the gear 18 is loosely fitted. On each power shift shaft 16, 17, an _F1 hydraulic clutch 24, an _F2 hydraulic clutch 25, an _F3 hydraulic clutch 26, an R hydraulic clutch 27 are arranged on each of the above-mentioned free rotating gears 20, 21, 22, 23. are installed, and each of these hydraulic clutches 24, 25, 26 or 27
selectively actuates each idler gear 20, 21, 22.
Alternatively, 23 can be selectively connected to each power shift shaft 16 or 1.
7.
The power shift shaft 16 is connected to the hollow power transmission shaft 9 by meshing a gear 28 fitted on the rear end of the power shift shaft 16 with a large diameter gear 29 on the front end of the hollow power transmission shaft 9. In addition, the other power shift shaft 17 connects the gear 30 fitted to the rear end of the power shift shaft 17 to the hollow power transmission shaft 9.
It is connected by meshing with the small diameter gear 31 on the front end. As described above, the hydraulic clutch type transmission 10 selectively shifts each idle gear 20, 21, 22, or 23 to each power shift shaft 16 or 17 by selectively operating each hydraulic clutch 24, 25, 26, or 27.
By connecting the hollow transmission shaft 9 to the
It is possible to selectively obtain the rotational speed of F ₁ , 2nd forward speed F ₂ , 3rd forward speed F ₃ or 1st reverse speed R.

As shown in FIG. 3, the clutch housing 2 is open at the rear end, and the transmission case 4 is open at the front end.
and transmission case 4 are screw rods 32 for multiple pieces.
and a nut 33 to tighten and fix. The rear end portions of the power shift shafts 16 and 17 are rotatably supported by support wall portions 4a and 4b that protrude from the inner surface of the transmission case 4, respectively. In particular, the slightly thin oil path forming plate 3
4, a spacer plate 35 made of a thin iron plate, and a thick oil passage forming/bearing plate 36 are provided in the clutch housing 2, overlapping in this order from the front side,
As shown in FIGS. 4 and 5, these plates 34, 35, and 36 are integrally formed with a plurality of connecting portions 36a extending rearward from the rear peripheral end portion of the oil passage forming/bearing plate 36. At the same time, a plurality of connecting portions 4c that abut against the end face of the connecting portion 36a are formed protrudingly on the inner surface of the transmission case 4, and penetrate through the oil path forming plate 34, the intermediate plate 35, and the oil path forming plate 36. When the three plates 34, 35, and 36 are fastened together by the threaded rod 37 which is inserted through the connecting part 36a and then screwed into the connecting part 4c on the inner surface of the mission case 4. At the same time, it is fixedly connected to the mission case 4.

Then, as shown in FIG. 3, the power shift shaft 1
Bearings 38,
It is bearing a bearing via 39. Similarly, the third
As shown in the figure, the drive shaft 8 located on the drive side of the hydraulic clutch type transmission 10 also connects its midway through the oil passage forming/bearing plate 3 via a bearing 40.
6, and furthermore, the support shaft 23B of the R intermediate gear 23A is also supported by the three plates 3.
4, 35, and 36 are supported. In the illustrated case, the transmission shaft 11 constituting the output shaft of the traveling power transmission units 10 and 12 is similarly connected to the third transmission shaft.
As shown in the figure, when converting the illustrated agricultural tractor to a four-wheel drive type, the output gear 41 for extracting the front wheel drive force is placed forward of the oil path forming plate 34 and the transmission gear is extended forward. The front end of the transmission shaft 11, which is fitted onto the shaft 11 and extends forward in this way, is also supported by the plates 34, 35, and 36 via a pair of bearings 42 and the like.

As shown in FIG. 3, the rear end side of the drive shaft 8 in the hydraulic clutch type transmission 10 is supported via a bearing 43 on a support wall 4d that is vertically disposed on the inner surface of the top wall of the transmission case 4. Furthermore, the rear end of the transmission shaft 11 is also supported by the support wall 4d via a bearing 44, and the transmission members 20, 23, 24, 2 on the power shift shaft 16
7 is an oil passage forming/bearing plate 36 and a transmission case 4
The transmission members 21, 22, 25, 26 on the power shift shaft 17 are connected between the support wall portion 4a on the inner surface, and between the oil passage forming/bearing plate 36 and the support wall portion 4b on the inner surface of the transmission case 4. , respectively, and the approximately front half of the hydraulic clutch type transmission 10 supported by the transmission case 4 is placed inside the clutch housing 2, and the rear end of the housing is Insert it through the opening,
Thereafter, the clutch housing 2 and the transmission case 4 are fixed using the screw rod 32 and nut 33.

As shown in FIG. 3, a housing 45 is mounted on the front surface of the oil passage forming plate 34 so as to straddle the drive shaft 8 and the power shift shaft 16. Approximately half of this housing 45 An internal gear type hydraulic pump 46 having a pump case is provided. This hydraulic pump 46 is configured so that the drive shaft 8 also serves as a pump shaft, and the hydraulic clutch type transmission device 1
The hydraulic clutch 24-27 at 0 is supplied with hydraulic oil. The other half of the housing 45 described above is formed into a cylindrical portion 45a whose front end opening is closed by a lid 47, and the front end of the power shift shaft 16 is exposed within this cylindrical portion 45a. be. Then, by using the flat part 16a formed at the front end of the power shift shaft 16, a friction braking plate 48 facing the stepped part 45b on the inner surface of the cylindrical part 45a is placed on the front end so that it cannot rotate relative to the shaft 16. A brake 49 is provided that brakes the power shift shaft 16 by press-fitting the friction brake plate 48 to the stepped portion 45b. Inside the cylindrical portion 45a, there is a piston 50 that faces the friction brake plate 48, and a piston 50 that connects the friction brake plate 4 through the piston 50.
A compression spring 51 is provided to urge the spring 8 to move in the direction of pressure contact with the stepped portion 45b. brake 49
The braking operation is performed by the biasing force of the compression spring 51 mentioned above, and the braking is released by retracting the piston 50 by hydraulic action on the oil chamber 52 formed in the cylindrical portion 45a. It is configured. The function of this brake 49 will be described later.

In the oil path forming/bearing plate 36, on the circumferential surface of each power shift shaft 16, 17, an annular groove is formed on the circumferential surface to distribute oil to two shafts. Rooms 53F ₁ , 53R and 53F ₂ , 53
_F3 is provided. These oil distribution chambers 53F ₁ , 53
R, 53F ₂ , 53F ₃ are each power shift shaft 16,
The corresponding hydraulic clutches ₂₄ , ₂₇ and ₂
5, 26 oil chambers 24a, 27a and 25a, 26
It is connected to a. Each hydraulic clutch 24,
25, 26, 27, as shown in FIG. 3 with reference numerals only for the F ₁ hydraulic clutch 24.
A clutch housing 55 fixed to each power shift shaft 16, 17 and each free rotating gear 20, 21, 22,
23, one and the other friction elements 56,
57 is slidably supported, and the piston 58 in the clutch housing 55 is connected to each of the oil passages 54.
Oil chamber 2 via F ₁ , 54F ₂ , 54F ₃ , 54R
4a, 25a, 26a, and 27a, which presses the friction elements 56 and 57 to obtain clutch engagement. This is done by causing the piston 58 to retreat by the return spring 59 upon release of the above-mentioned hydraulic action. The power shift shafts 16 and 17 also include the shaft 1
Lubricating oil passages 62, 63 are also formed for supplying lubricating oil from oil chambers 60, 61 provided in front of the hydraulic clutches 6, 17 to the friction elements 56, 57 of the hydraulic clutches 24, 27 and 25, 26, respectively. . As shown in FIG.
The bearings, which are provided with needle bearings 64, 65 as shown, also extend rearward to supply lubricating oil. Third
In the figure, 66 is a relief valve installed on the front surface of the oil passage forming plate 34 so as to close the oil chamber 61' in front of the power shift shaft 17 from the front side. Provided to set oil pressure.

As shown in FIG. 4, the hydraulic clutches 24-27 in the hydraulic clutch type transmission 10 are inserted into the valve holes formed along the vertical direction of the oil path forming/bearing plate 36. A spool 68 that constitutes a switching valve 67 that switches and controls supply and discharge of hydraulic oil is provided. Similarly, as shown in FIG. 4, a pressure regulating valve is inserted into a support hole formed vertically along the oil path forming/bearing plate 36 to control the hydraulic pressure applied to the plurality of hydraulic clutches 24-27. 69 are provided.

As mentioned above, the hydraulic pump 46 mounted on the front surface of the oil passage forming plate 34 is intended to supply oil to the hydraulic clutch type transmission 24-27. The required oil passage from the discharge port is formed as follows. That is, as shown in FIG. 3-5, the oil passage forming plate 3
On the back side of 4, a plurality of oil grooves _G1 are formed at appropriate locations, and an oil path forming/bearing plate 3 is formed.
A plurality of oil grooves G 2 are formed on the front surface of the oil groove G ₂ at appropriate locations, and these oil grooves G ₁ and oil grooves
G ₂ refers to the side that is opened by the intervening plate 35 (that is, the oil groove G ₁ is located on the back side of the plate 34,
Regarding G ₂ , the front side of plate 36) is closed.
The oil discharge port of the hydraulic pump 46 passes through an oil hole in the housing 45 and an oil hole (not shown) in the oil path forming plate 34, and then connects to an oil groove G on the back surface of the oil path forming plate 34. ₁ as appropriate, and the oil groove G ₁
Further, an oil passage/bearing plate 36 is formed by an oil hole (not shown) appropriately formed by penetrating the spacer plate 35.
It is appropriately connected to the oil groove G ₂ on the front surface. Furthermore, the oil groove G ₂ is connected to the switching valve 67 as appropriate.
and the pressure regulating valve 69, and
The secondary side port of the switching valve 67 is connected to the oil distribution chamber 53 through the oil groove G ₂ and the oil hole in the oil path forming/bearing plate 36 (an example of which is the oil hole 70 shown in FIG. 3).
It leads to F ₁ , 53F ₂ , 53F ₃ , and 53R. The relief port of the pressure regulating valve 69 is guided into the oil chambers 60, 61 in substantially the same manner as described above, and the tank port of the switching valve 67 is also guided into the clutch housing 2 in substantially the same manner as described above. ing.

The brake 49 described above has the function of braking the power shift shaft 16 when the hydraulic clutch type transmission 10 is in a neutral state, and thereby braking the rear wheel axle 6a to prevent the vehicle from starting unexpectedly. Therefore, for the oil chamber 52 of the brake 49,
Hydraulic pressure is applied only when the hydraulic clutch type transmission 10 is in a gear change state, and when the braking operation of the brake 49 is released and the hydraulic clutch type transmission 10 is switched to the neutral state, the hydraulic pressure is automatically applied to the oil chamber 52. is released so that the brake 49 operates under the action of the compression spring 51. The automatic switching control of the brake 49 operation as described above is known from Japanese Patent Application Laid-Open No. 53-45830, etc., from the hydraulic pump 46 to the switching valve 6.
This is done by connecting the oil supply circuit leading to the brake oil chamber 52, that is, the oil supply circuit in which the hydraulic pressure is released at the neutral position of the switching valve 67 and the oil pressure is established at each operating position, to the brake oil chamber 52. A connection oil passage for this is formed within the housing 45.

As shown in FIG. 6, a supporting wall portion 2b is provided in the clutch housing 2 at a position forward of the oil passage forming plate 34 and is integral with the housing 2, and the front end portion of the drive shaft 8 is It is supported by this support wall portion 2b via a ball bearing 93. Similarly, as shown in FIG. 6, the support wall portion 2b extends below the bottom wall of the clutch housing 2, and the transmission shaft 11 is attached to the support wall portion 2b at the extended portion. When the output gear 41 (FIG. 3) at the end is used to extract the front wheel driving force, the cylindrical portion 2c through which the transmission shaft for power extraction is inserted and supported is integrally formed, and is suitable for two-wheel drive tractors. At this time, the open end of the cylindrical portion 2c is closed with a lid 94. As shown in FIG. 4, the oil passage forming/bearing plate 36 has a hole 95 concentric with the cylindrical portion 2c through which the power extraction transmission shaft is inserted and supported. Although not shown, similar holes are also bored in the oil passage forming plate 34 and the spacer plate 35.

In FIG. 3, reference numeral 71 denotes a one-way clutch disposed between the _F3 free rotating gear 22 and the power shift shaft 17 in the hydraulic clutch type transmission 10. 52−
As is known from Publication No. 131065, etc., when driven from the power shift shaft 17 side in a relatively normal rotation direction (vehicle forward direction), it engages and connects the F ₃ idler gear 22 to the power shift shaft 17. This makes it easier to pull the engine 1. In the illustrated case, the one-way clutch 71 is arranged on the extension 30a of the boss portion of the gear 30 fitted to the power shift shaft 17, so that the one-way clutch 71 is arranged on the extension 30a of the boss part of the gear 30 fitted to the power shift shaft 17, and vice versa. The key 72 is designed to be long.

Next, the structure of other parts of the illustrated agricultural tractor will be briefly explained. As shown in FIGS. 2 and 3, the mechanical transmission 12 includes two The speed change gears 73 and 74 are integrally formed, and two free rotation speed change gears 75 and 76 are loosely fitted on the transmission shaft 11, and the large diameter side free rotation speed change gear 75 is attached to a hollow transmission shaft. The small-diameter free rotating gear 76 is meshed with the gear 29 on the hollow transmission shaft 9, respectively. Also provided on the transmission shaft 11 is a shift gear 77 which is slidable by spline fitting but cannot rotate relative to the shaft 11. This shift gear 77 is connected to the transmission gear 74 on the hollow transmission shaft 9.
an engaging pawl 77a that is formed to be able to mesh with an engaging pawl 75a formed on the boss portion of the idle speed change gear 75;
Internal teeth 77b that can be engaged with the idle speed change gear 76 are formed. As described above, the mechanical transmission 12 selectively slides and displaces the shift gear 77 on the transmission shaft 11, and the engagement pawl 77
a is engaged with the engagement pawl 75a and the idle speed change gear 75 is connected to the transmission shaft 11, thereby achieving the 1st speed change ratio, and the shift gear 77 is connected to the speed change gear 7 on the hollow transmission shaft 9.
4, the internal teeth 77b are meshed with the idle speed change gear 76, and the gear ratio of the second speed is achieved.
By connecting to the transmission shaft 11, a 3rd speed gear ratio is achieved.
The hollow power transmission shaft 9 and the power transmission shaft 11 are respectively selectively interlocked and connected.

Further, the drive shaft 8 extends from the inside of the transmission case 4 to the inside of the rear housing 5, and within the rear housing 5, another concentric drive shaft 79 is connected to the drive shaft 8 by a coupling 78. As shown in FIG. 2, a PTO transmission 80 is provided between the other drive shaft 79 and the PTO shaft 7 to change the speed of the working machine power.
This PTO transmission 80 includes three speed change gears 81, 82, 83 fixed to a drive shaft 79,
An idler gear 84 is loosely fitted onto the PTO shaft 7 and meshed with the smallest diameter speed change gear 81 among the speed change gears 81 to 83, and two integral gears are provided on the PTO shaft 7 so as to be able to slide only freely. Shift gears 85 and 86, and meshing pawls 87a and 87b are formed on the boss portions of idle gear 84 and shift gear 85, respectively.
A meshing clutch 87 interposed between 4 and 85,
We are prepared. And this PTO transmission 80 is
By selectively slidingly displacing the shift gears 85 and 86 on the PTO shaft 7, and engaging the clutch clutch 87 by the meshing between the meshing pawls 87a and 87b, the free rotating gear 84 is coupled to the PTO shaft 7. The gear ratio of 1st gear can be selectively obtained, the gear ratio of 2nd gear can be selectively obtained by meshing between gears 82 and 85, and the gear ratio of 3rd gear can be selectively obtained by meshing between gears 83 and 86, It is configured.

In FIG. 1, reference numeral 88 denotes a main shift lever for changing the gear stage of the hydraulic clutch type transmission 10 by displacing the switching valve 67. It is connected to the spool 68 via a mechanism 89. Similarly, in FIG. 1, reference numeral 90 indicates an auxiliary gear shift lever for displacing the shift gear 77 to change the gear stage of the mechanical transmission 12, and 91 indicates the shift gear 8.
This is a PTO shift lever for changing the gear stage of the PTO transmission device 80 by displacing the gears 5 and 86. Further, in FIG. 2, reference numeral 92 denotes a brake provided on each of the above-mentioned differential gear output shafts 14a.

As is clear from the above explanation, this invention is different from conventional agricultural tractors in which only the main clutch is installed inside the front end, and more than half of the interior is a dead space with only one transmission shaft. Since a part of the traveling power transmission devices 10 and 12, which occupy a large longitudinal length in the body, are inserted and installed in the clutch housing, the longitudinal length of the body of the agricultural tractor can be shortened accordingly. Moreover, in this invention, the bearing plate 36 connected and supported by the transmission case 4 is provided in the clutch housing 2, and the front end sides of the plurality of transmission shafts 8, 16, 17 on which the transmission members are mounted are connected to the clutch housing 2. Since the traveling power transmission is supported only by the transmission case 4 by supporting it on the bearing plate 36 instead of on the A part of the transmission can be inserted and installed into the clutch housing 2 from the rear end side of the housing, making it easy to assemble the running power transmission into the agricultural tractor. Furthermore, by supporting the traveling power transmission in the transmission case 4, a part of the transmission is disposed inside the clutch housing 2 to shorten the fuselage length. This makes it possible to use lightweight products such as those made by other manufacturers, contributing to overall weight reduction and cost reduction of agricultural tractors.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of an agricultural tractor equipped with an embodiment of the present invention, FIG. 2 is a mechanical diagram showing the transmission mechanism of the tractor, and FIG. 3 is a partially exploded longitudinal sectional side view of the main parts of the tractor. Figure 4 is - of Figure 3.
FIG. 5 is a cross-sectional plan view of only the main parts of the tractor, and FIG. 6 is a vertical cross-sectional side view of only the main parts of the tractor. 2... Clutch housing, 2a... Front end large diameter part,
3... Main clutch, 4... Mission case, 4a,
4b, 4d... Support wall portion, 4c... Connection portion, 8... Drive shaft, 9... Hollow transmission shaft, 10... Hydraulic clutch type transmission, 11... Transmission shaft, 16, 17... Power shift shaft, 18, 19... Speed change Gears, 20, 21, 22,
23... Idle gear, 24, 25, 26, 27... Hydraulic clutch, 28, 29, 30, 31... Gear, 32
...Screw rod, 33...Nut, 34...Oil path forming plate, 35
...Interval plate, 36...Oil path forming/bearing plate, 36a...Connection part, 37...Screw rod, 45...Housing, 46...Hydraulic pump, 48...Friction brake plate, 53F ₁ , 53F ₂ ,
53F ₃ , 53R...Oil distribution chamber, 54F ₁ , 54F ₂ ,
54F ₃ , 54R...Oil passage, 67...Switching valve, 69...
Pressure regulating valve.

Claims (1)

[Claims] 1. In an agricultural tractor in which a clutch housing containing a main clutch and a transmission case containing a variable speed transmission mechanism are arranged in series in the front end, a plurality of The bearing plate 3 is connected and supported by the transmission case 4 through the connecting portions 36a.
6 is provided in the clutch housing 2 with an interval in the front-rear direction between it and the transmission case 4, and a plurality of power transmission shafts 8, 16, 1 along the front-rear direction are provided.
7 are respectively supported by the bearing plate 36 and the supporting walls 4a, 4b, 4d on the inner surface of the transmission case, and are installed on these transmission shafts 8, 16, 17 to change the speed of the traveling power. Some of the transmission gears 19 and 2 of the transmission gears and clutches that perform
1, 23 and clutches 25, 27 are disposed within the clutch housing 2.