JPS5921954Y2 - Traveling power transmission device for agricultural tractors, etc. - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a traveling power transmission device for transmitting engine power to driving wheels or crawlers in an agricultural tractor or the like.

When a mechanical transmission installed in this type of driving power transmission device is put into a neutral state, the driving power transmission path is cut off at the transmission part, but even in this neutral state, the engine side The rotational torque transmitted from the transmission shaft on the driving side of the transmission, or from the wheel or crawler side that is about to rotate spontaneously on a slope, etc., to the transmission shaft on the driven side of the transmission, is used as a mechanical retaining part for transmission. An unexpected engagement may occur, causing the vehicle to start unexpectedly, which may be dangerous.

The purpose of this invention is to provide a novel running power transmission device for agricultural tractors, etc., which is designed to eliminate such inconveniences and has a simplified structure. It is in.

Regarding the illustrated embodiment, the configuration of the traveling power transmission device for an agricultural tractor or the like according to this invention will be explained. As shown in FIG. The power is transmitted toward the rear of the fuselage within the clutch housing 2, transmission case 3, and rear housing 4, which make up the fuselage, respectively, and drives the left and right rear wheels 5 to cause the aircraft to travel, and extends to the rear of the fuselage. This invention is implemented as follows in an agricultural tractor configured to rotationally drive a PTO shaft 6 for driving a working machine.

That is, in the illustrated agricultural tractor, a drive shaft 7 directly connected to the engine 1 is provided in the transmission case 3 as shown in FIG. An offshore drive shaft 8 is provided on the drive shaft 7 in the front half of the mission case 3, and this hollow drive shaft 8 is
The engine 1 is connected via a main clutch 9 schematically shown in FIG.
It is linked to.

A mechanical running power main transmission 11 configured as described below is provided between the hollow drive shaft 8 and a transmission shaft 10 provided along the hollow drive shaft 8 at a lower position in the front half of the mission case 3. A mechanical running power sub-transmission (not shown) connected in series to the main transmission 11 is provided in the rear half of the transmission case 3.

Here, the configuration of the above-mentioned traveling power main transmission 11 is changed to a second one.
To explain the diagram, this transmission 11 includes F1 speed change gears 1 fixedly provided on a hollow drive shaft 8, respectively.
2, the F2 speed change gear 13, the F3 speed change gear 14, the F4 speed change gear 15, the R speed change gear 16, and the speed change idle gears 17-21, which are loosely fitted to the transmission shaft 10, and are disposed on the hollow drive shaft 8. F1 idle speed change gear 17, F which is meshed with the corresponding speed change gear 12-16 directly (F speed change idle gear 17-20) or indirectly (R speed change idle gear 21) via the R intermediate gear 16a. , idle speed change gear 18, F3 idle speed change gear 19, F4 idle speed change gear 20, and R idle speed change gear 2
1. It is equipped with.

The traveling power main transmission 11 selectively connects each of the idle speed change gears 17, 18, 19, 20 or 21 to the transmission shaft 10, thereby correspondingly providing first forward speed F1 and second forward speed. F2, 3 forward speed F3, 4 forward speed F4 or 1 reverse speed R
The hollow drive shaft 8 and the transmission shaft 10 are selectively interlocked and connected with a speed ratio of .

In order to selectively couple each idle speed change gear 17-21 to the transmission shaft 10, each idle speed change gear 1
7.21 meshing teeth 17a, 21a and cone-shaped friction surface 1
7 b, 21 b, and the meshing teeth 17
a, meshing teeth 22a aligned with 21a.

23a and friction surfaces 22b, 23b that can be frictionally engaged with the friction surfaces 17b, 21b.
are provided on the friction surfaces 17b and 21b, and the transmission/drive shaft 1
- A sliding block 25 and a shifter sleeve 26 are provided on the bub 24 fixed at 0, and by sliding displacement operation of the shifter sleeve 26, the meshing teeth 26a on the inner circumferential surface of the sleeve 26 are first moved from the periodic ring 22 or is 23 meshing teeth 22 a
Alternatively, the friction surface 1 is meshed with the sliding block 23a, and the sliding block 25 is displaced, and the pushing action of the block 25 pushes the friction surface 1.
7 b, 22 b or 21 b, 23 b, and in this state, the shifter sleeve 26 and the synchronizing ring 22 or 2 cannot rotate relative to the transmission shaft 10.
3 comes to rotate synchronously with the speed change idle gear 17 or 21 on the drive side due to the frictional engagement between the friction surfaces 17b, 22b or 21b, 23b, and the meshing teeth 26a, 22a or 26a,
23a and the meshing teeth 17a, 21a are aligned, and the sleeve 2, which was previously blocked, is
If 6 displacements are allowed, the sliding displacement of the shifter sleeve 26 will cause the meshing teeth 26a of the sleeve 26 to interact with the meshing teeth 22a or 23a of the synchronization ring 22 or 23 and the idle speed change gear 17. Or 21 meshing teeth 17a or 21a
The idling speed change gear 17 or 21 is connected to the transmission shaft 10 by straddling and meshing the two.

That is, the synchronous meshing mechanism of the Borgwarna set is configured to selectively connect each of the idle speed change gears 17 to 21 to the transmission shaft 10, and when the mechanical driving power main transmission 11 is changed speed. This is designed to prevent noise, damage and wear of gears, etc., and to allow easy and quick gear shifting operations.

As described above, as shown in FIG. 2, the following brake 27 is provided at the front end of the transmission shaft 10 located on the driven side of the main transmission 11. .

That is, the transmission shaft 10 extends into the clutch housing 2 by penetrating the clutch housing 2 and the spacer plate 28 interposed in the transmission case 3, and has a flat notch 10a at the extending end. The cutout portion 10 a is provided with a
At the top, a friction brake plate 29 is provided so as to face a fixed disk 30 mounted on the front surface of the interplate 28 so as to be unable to rotate relative to the shaft 10.

A housing 31 is fixedly attached to the front surface of the fixed disk 30, and a piston 32 facing the friction brake plate 29 is slidably provided in the housing 31.

The brake 27 applies hydraulic pressure to an oil chamber 33 formed in the housing 31 on the front side of the piston 32 to move the piston 32 forward in the direction of the friction brake plate 29 and press the brake plate 29 against the fixed disk 30. Through frictional engagement,
□It is configured to obtain braking action, and the brake 27
To release the brake, the hydraulic action on the oil chamber 33 is released and the compression spring 34 provided between the fixed disk 30 and the piston 32 is released.
This is done by retracting the piston 32.

Similarly, as shown in FIG. 2, on the hollow drive shaft 8,
A hydraulic pump 35 is mounted on the front surface of the spacer plate 28 and is driven by a hollow drive shaft 8 within the rear end of the clutch housing 2.
This is provided.

The oil discharge port of this hydraulic pump 35 is connected to the oil passage 3 in the spacer plate 28.
6. Although the oil passage 37 in the fixed disc 30 and the oil passage 38 in the housing 31 are connected to the oil chamber 33 described above, the following is provided between the hydraulic pump 35 and the brake oil chamber 33. A valve mechanism is provided as described in .

First, this valve mechanism will be explained with reference to a circuit diagram. As shown in FIG. An oil supply circuit 40 that supplies hydraulic oil to the oil passages 36 and 37, a part of which is
．． Three switching valves 41, 42, 43 are inserted in series into the oil supply circuit 40 formed by 38, and each of the switching valves 41, 42, 43 directs the oil supply circuit 40 toward the oil chamber 33. Positions II and III, which block the oil supply circuit 40, are provided on one or both sides of position (1), which is connected to position (2).

These switching valves 41, 42, and 43 are configured to be displaced by a main shift lever 44 for shifting the driving power main transmission 11, as will be explained later.

Similarly, as shown in FIG.
0 to the oil chamber 33;
The oil chamber 33 is configured to have an unloading position II for causing the hydraulic oil in the oil chamber 33 to flow toward the oil tank 39 and unloading the hydraulic pressure in the oil chamber 33.

The specific structure and operation mechanism of this unload valve 45 will be explained later, but this valve 45 is configured to be displaced by a main clutch pedal 46 for disengaging the main clutch 9.

Further, as shown in FIG. 3, the hydraulic pressure applied to the oil chamber 33 is set by a pressure regulating valve 48 inserted into a relief circuit 47 connected to the oil supply circuit 39. It is led to an oil tank 39 via a lubricating section, which will also be explained in detail later.

The specific structure of the switching valves 41, 42, 43 and their operating parts shown in FIG. 3 will be explained below.
The idle speed change gears 17-21 are selectively connected to the transmission shaft 10.
In addition to the shifter sleeve 26 for the F1 idle speed change gear 17 and the R idle speed change gear 21, the shifter sleeve corresponding to the shifter sleeve 26 for coupling to the second
Each illustration is omitted in the figure.

A shifter sleeve for the F2 idle speed change gear 18 and the F3 idle speed change gear 19 and a shifter sleeve for the F4 idle speed change gear 20 are provided, and a total of three shifter sleeves are provided.

And these three shifter sleeves are 4.5
As shown in the figure, a shift fork 53 is fixedly supported by three fork shirts T-50, 51, and 52, which are provided parallel to each other in an operating mechanism housing 49 installed on the upper surface of the mission case 3. 54.55
The lower ends of the shifter sleeves are engaged with the three shifter sleeves, and the main shift lever 44 is rotated in the direction of arrow A in FIG. After being selectively engaged, the main shift lever 44 is rotated in a direction perpendicular to the direction of arrow A (direction of arrow B in FIG. 6) to shift each shift fork 53, 54 or 55. (the fork shirt on which it is placed) 50, 51 or 52 are displaced, thereby obtaining and performing selective sliding displacement of each shifter sleeve.

FIG. 6 shows the lever guide 56 of the main shift lever 44, and the lever guide 56 has a guide groove extending in the direction of arrow B and a guide groove extending in the direction of arrow B. A groove 56a is formed, and the ends of the three guide grooves along the direction of arrow B are connected to the first forward speed F1.
and fork shaft 50 and shift fork 53 for reverse 1st speed R, and fork shaft 51 and shift fork 54 for forward 1st speed position F1, reverse 1st speed position R1, forward 2nd speed F2, and forward 3rd speed F3. move forward 2
The speed position F2, the third forward speed position F3, and the fourth forward speed position F4 are set in correspondence with the fork shaft 52 and shift fork 55 for the fourth forward speed.

In particular, the three fork shafts 50, 5 mentioned above
As shown in FIGS. 4 and 5, the support metal fitting 60 at one end of the operating mechanism housing 49, which slidably supports one end of 1.52 with the support hole 57, 58, 59, has the above-mentioned support hole. 57, 58, and 59 is formed, and this oil passage 61 has one end connected to another oil passage 62 in the support hardware 60, an oil passage 63 in the top wall of the mission case 3, and It is connected to the oil discharge port of the hydraulic pump 35 via an oil passage (not shown) in the spacer plate 28, and the other end is connected to another oil passage 64 in the support hardware 60 and the transmission case 3. Oil passage 65 in the top wall and the aforementioned oil passages 36, 37, 38
(Fig. 2) to the oil chamber 33 of the brake 27.

The fork shafts 50, 51, 52 have the main shift lever 44 positioned in the guide groove along the direction of arrow A in the lever guide 56, that is, all the fork shafts 50, 51, 52 are in the neutral position N. In the state of sliding displacement, the oil supply holes 50a, 51a, 52a aligned with the oil passage 61 are connected to the shaft 5.
This is a through-hole formed across 0-52.

Therefore, in the neutral state of the traveling power transmission 11 in which the main shift lever 44 is located in the guide groove 561 section along the direction of arrow A in the lever guide 56 and all the fork shafts 50, 51, 52 are in the neutral position N, the supporting metal 6
50.51.5 The oil passage 61 in 0 is the fork shirt)
The oil supply holes 50a, 51a, 52a in FIG. F2. F3. F4 or R
any gear F of the main transmission 11 that is
1. F2. F3. In the transmission state of transmission at F4 or R, the oil passage 61 in the support metal fitting 60 is blocked midway by one of the fork shafts 50, 51 or 52.

That is, the fork shaft 50, 51, 52, together with its oil supply holes 50a, 51a, 52a, constitute a switching valve corresponding to the switching valve 41, 42, 43 in FIG. The positions N, F1, and R correspond to the positions ■, II, and III of the switching valve 41, respectively, and the neutral positions N, F2, and F3 of the fork shaft 51 correspond to the positions ■, II, and II of the switching valve 42, respectively. In addition, the neutral position N and F4 position of the fork shaft 52 correspond to the position of the switching valve 43.
and position II, respectively.

Next, the specific structure and operating mechanism of the unload valve 45 shown in FIG. 3 will be explained.As shown in FIG.
The transmission shaft 1 is slidably supported by the housing 31.
A reciprocating rod 66 concentric with 0 is provided with its base end extending outside the housing 31.

The advancing/retracting rod 66 is urged to slide in the direction of protruding into the housing 31 by a compression spring 67 provided inside the housing 31 with both ends received by the head 66 a at the tip and the inner surface of the housing 31. , a small diameter portion 66 b is formed near the tip of the advancing/retracting rod 66 .
6 is pulled out slightly against the spring 67 force from the position shown by the solid line in FIG. 2 and brought to the position shown by the chain line. The portion 66b is designed to communicate with the space 68 in the housing 31 via the outer periphery.

The above-mentioned space 68 is connected to the inside of the mission case 3 via an oil passage 69 formed in the housing 31, an oil passage 70 formed in the fixed disk 30, and an oil passage 71 formed in the spacer plate 28. Let's communicate.

As described above, when the advancing/retracting rod 66 is pulled out beyond the position shown by the chain line in FIG. The oil pressure in the oil chamber 33 is unloaded.

That is, the unloading valve 45 is configured with the advance/retreat rod 66 as a valve spool.
The solid line position 6 in FIG. 2 corresponds to the unloading non-operating position (2) of the valve 45, and the position pulled out beyond the chain line position corresponds to the unloading operating position II of the valve 45, respectively.

While the specific structure of the unload valve 45 is as described above, the operating mechanism of the valve 45 is constructed as follows.

That is, as shown in FIGS. 2 and 7, an operating shaft 72 along the transverse direction of the fuselage is rotatably supported on one side wall of the clutch housing 2, and the above-mentioned advance/retreat rod 66 is supported on one side wall of the clutch housing 2.
A pin 73 extending in the same direction is fixed to the base end of.

An operating hardware 74 having a pair of left and right operating arms 74a that engages the pin 73 from the rear side of the machine body is fixed to the tip of the operating shaft 72, and the operating hardware 74 is fixed to the tip of the operating shaft 72 in the direction of arrow C in FIG. With rotational displacement, the actuating arm 74a causes the pin 7 to
3 to pull out and displace the retractable lever 66.

The main clutch 9 described above is disengaged by depressing the main clutch pedal 46 as described above, and as shown in FIG. Pedal arm 4 to hardware 76
6 a is fixedly provided, and the pedal arm 46
a, the above-mentioned rotating hardware 76, a rotating arm 77 on this rotating hardware 76, an advancing/retracting rod 78 whose rear end is pivotally attached to this rotating arm 77, and a rotating arm 7 to which the tip of this advancing/retracting lever 78 is pivotally attached.
9. Rotating hardware 81 on the fulcrum shaft 80 of this rotating arm 79
The main clutch 9 is interlocked and connected to a cam mechanism (not shown) provided in the clutch housing 2 for disengaging the main clutch 9, thereby forming a well-known main clutch disengaging operation mechanism.

As shown in FIG.
On the outside, the main clutch 9 is operated by a rotating arm 83 having a pin 82 fixed to the operating shaft 72, and an advancing/retracting rod 84 whose both ends are pivotally connected to the rotating arm 83 and the rotating hardware 19 in the main clutch 9 operating mechanism. It is operatively connected to an operating mechanism, and is designed so that when the main clutch pedal 46 is depressed, the advancing/retracting lever 66 is pulled out beyond the position shown by the chain line in FIG.

That is, the unload valve 45 is displaced to the unload action position II' by the disengagement operation of the main clutch 9, and unloads the hydraulic pressure in the oil chamber 33 of the brake 27.

Note that the advance/retreat rod 84 is provided with a length adjustment portion 84a for adjusting the timing of the operation of the pulse 145.

Next, the lubrication mechanism described above with reference to FIG. 3 will be explained. As shown in FIG. 2, inside the fixed disk 30,
An oil passage 85 is provided in the relief circuit 47 on the tip side of the pressure regulating valve 48, and this oil passage 85 is connected to an annular groove 86 provided on the circumferential surface near the tip of the transmission shaft 10. It's like opening your eyes.

This annular groove 86 is connected to a lubricating oil passage 87 formed along the axial direction of the transmission shaft 10, and this lubricating oil passage 87 is as illustrated for the R idle speed change gear 21 in FIG. Then, the oil is guided to the support portion of each free rotating speed change gear 17, 18, 19, 20, 21 on the transmission shaft 10 via a branch oil passage 88 formed in the transmission shaft 10 so as to be perpendicular to the oil passage 87. be.

In other words, the lubricated portion described with reference to FIG. 3 is a support portion of the idle speed change gear 17-21.

The above-mentioned traveling power sub-transmission device, which is provided after the traveling power main transmission device 11, has its front end supported by the hollow support portion 89 at the rear end of the transmission shaft 10, as shown in FIG. Another transmission shaft 90 provided on the extension line of the transmission shaft 10,
It is configured as a mechanical transmission that is selectively coupled to the transmission shaft 10 at an appropriate speed ratio, and the speed is changed by an auxiliary speed change lever 91 shown in FIG.

In FIG. 1, reference numeral 92 denotes a PTO speed change lever for a PTO speed change device provided within the rear end portion of the rear housing 4.

The illustrated traveling power transmission device according to this invention is constructed as described above, and has the following advantageous effects.

That is, in the above-mentioned brake 27, when the traveling power main transmission 11 is in a transmission state, the oil passage 61 in the support metal fitting 60 is blocked by any of the fork shafts 50, 51, or 52, and the switching valve 41 is blocked. , 42.43
Since one of the switching valves 41, 42, or 43 is in position II or III, and the oil supply circuit 40 is blocked, no oil pressure acts on the oil chamber 33, and therefore the compression spring 34, the piston 32 is retracted, the friction brake plate 29 is no longer pressed against the fixed disc 30, and no braking operation is performed. There is no problem in terms of power transmission, such as braking of the power transmission shaft 10.

Under this condition, the oil discharged from the hydraulic pump 35 is discharged exclusively through the relief circuit 47 while causing the pressure regulating valve 48 to perform a relief operation. Oil for lubrication is forcibly supplied to the bearing, and the hydraulic pump 35 is effectively utilized.

Next, move the main gear shift lever to the guide groove 563 along the direction of arrow A in FIG.
．． 51.52 to the neutral position N and the traveling power main transmission 11 is in the neutral state, the oil supply holes 50a, 51a of all fork shafts 50.51.52.

52a are aligned with the oil passage 61 of the support hardware 60, and the full switching valves 41, 42, and 43 assume position I.

Therefore, at this time, the oil supply circuit 40 is unblocked, hydraulic pressure is applied to the oil chamber 33 of the brake 27, the piston 32 moves forward against the force of the compression spring 34, and the friction brake plate 29 is fixed to the disk. The brake 27 performs a braking operation by being brought into pressure contact with the surface 30 and frictionally engaged.

Therefore, in the neutral state of the driving power main transmission 11, the rotational torque being transmitted from the engine 1 side to the hollow drive shaft 8, and therefore to the idle speed change gears 17-21, or from the rear wheel 5 side to the transmission shaft. Due to the rotational torque that can be transmitted to the gearbox 10, it is certain that the transmission retaining part, which in the illustrated case has a synchronous clutch mechanism as described above, will be unexpectedly engaged and power transmission will occur. be prevented.

As mentioned above, the brake 37 is for preventing unexpected transmission when the transmission 11 is in the neutral state, and its braking force is relatively small. However, in the illustrated case, the speed change operation of the main transmission 11 is possible.
Since the synchronous clutch mechanism as described above is provided, when a speed change operation is performed under braking of the transmission shaft 10, each free rotating speed change gear 17-21 of the shifter sleeve 26 and the synchronization ring 22
It becomes difficult to obtain synchronized rotation with the

The main clutch 9 is disengaged as usual before the gear change operation of the mechanical driving power main transmission 11, but even if the main clutch 9 is disengaged in this way and the drive of the hydraulic pump 35 is stopped. Since the hydraulic oil is not actively discharged from the oil supply circuit 40, the residual oil pressure still acts on the oil chamber 33 of the brake 27, and the brake 27 continues to operate for a while, making it difficult to obtain the above-mentioned synchronous rotation. persists.

Therefore, the illustrated traveling power transmission device is provided with the above-mentioned unload valve 45, and this unload valve 45 is operated by depressing the main clutch pedal 46 and disengaging the main clutch 9 prior to the gear shifting operation. As a result, the retractable lever 66 is moved to the unloading position II' by pulling out the retractable lever 66, and the hydraulic pressure is unloaded from the oil chamber 33.

Therefore, as the main clutch 9 disengages, the braking action of the brake 27 is released, allowing the synchronous clutch mechanism to smoothly achieve a predetermined synchronous rotational action.

As is clear from the above description, the running power transmission device for an agricultural tractor or the like of this invention is arranged on the driven side transmission shaft 10 of the mechanical transmission 11 provided in the running power transmission path, and is operated by hydraulic pressure. The transmission shaft 10 is actuated by a spring 34 and released by the action of a spring 34.
A plurality of shift forks 53 and 54 are provided with a brake 27 for braking and operate the mechanical transmission 11 to change speeds.
．． (Multiple folk shirts that can fix 55) 50.5
1.52 respectively, these fork shafts 50.
The brake 27 is aligned at the neutral position of 51.52.
a hydraulic pump 35 for supplying hydraulic oil to the brake 2;
Oil supply holes 50a, 51a, 52 connecting between 7
As described in detail above, since the driven side transmission shaft is braked when the mechanical transmission is in the neutral state, the gear shift is performed when the transmission is in the neutral state. This reliably avoids the risk of unexpected engagement of the mechanical engagement portion for transmission and unexpected start of the vehicle.

Although the traveling power transmission device of this invention has such advantages, it utilizes a fork shaft for speed change operation, and the fork shaft is selectively slid between a neutral position and an operating position. , the oil supply hole is shaped to selectively apply hydraulic pressure to the brake, and the oil supply path is automatically opened and closed as the gear is changed, so there is no need to add an extra operating mechanism or noise. It is a device with a simple structure.

In addition, according to one embodiment of this invention, the brake 27
When connecting the synchronous clutch to the operation part 46 of the main clutch 9 of an agricultural tractor, etc., in such a way that the hydraulic pressure applied to the brake 27 is unloaded when the main clutch 9 is disengaged, the synchronous clutch is connected to the shift engagement part as described above. Even when a mechanism is provided, the brake 27 is released when the main clutch is disengaged prior to the gear change operation, so that the synchronous clutch mechanism can smoothly achieve a predetermined synchronous rotational action.

Further, according to another embodiment of the invention, the brake 2
When introducing the IJ-IJ flow circuit 47 into which the pressure regulating valve 46 is inserted for setting the working oil pressure for the mechanical transmission 11 to the lubricated part of the mechanical transmission 11, it is necessary to use a brake that exhibits the above-mentioned advantages. As described above, the practical benefit is that the hydraulic pump for supplying hydraulic oil can be effectively used as a hydraulic pump for supplying lubricating oil even when hydraulic oil is not being supplied to the brakes.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of an agricultural tractor equipped with an embodiment of this invention and its lid, Fig. 2 is a longitudinal side view of the same tractor with some main parts omitted and partially expanded, and Fig. 3 is a schematic side view of the lid of the same tractor. A circuit diagram of the hydraulic circuit, FIG. 4 is a cross-sectional plan view of the main parts of the same embodiment, FIG. 5 is a vertical cross-sectional front view of the main parts, FIG. 6 is a partial plan view of one member in the same embodiment, and FIG. 7 FIG. 2 is a longitudinal sectional front view of other main parts of the same embodiment. 2...Clutch housing, 3...Mission case, 5...Rear wheel, 8...
Hollow drive shaft, 10... Transmission shaft, 11...
・Travel power main transmission, 12.13.14゜15, 16
・・・・・・Speed gear, 17.18.19.20.21
...Idle speed change gear, 22.23...Synchronization ring, 26...Shifter sleeve, 27.
...Brake, 28...Interval plate, 30...
... Fixed disc, 31 ... Housing, 32
... Piston, 33 ... Oil chamber, 34.
...Compression spring, 35...Hydraulic pump, 40...Oil supply circuit, 41.42.43...
...Switching valve, main gear lever, 45.
...Unload valve, 46...Main clutch pedal, 47...Relief circuit, 48...
... Pressure regulating valve, 49 ... Operation mechanism housing, 50, 51.52 ... Fork shaft, 5
0 a, 51 a. 52 a... Oil supply hole, 53.54.55...
...Shift fork, 56...Lever guide, 60...Support hardware, 61...Oil passage,
66...Advancing/retracting rod, 66 b...Small diameter part, 72...Operation shaft, 73...Pin, 7
4... Operating hardware, 74 a... Operating arm, 79... Rotating arm, 83...
Rotating arm, 84...Advancing/retracting rod, 85...
・Oil passage, 87...Lubricating oil passage, 88...
Branch oil path, L...Lubricated part.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A transmission that is disposed on the driven side transmission shaft of a mechanical transmission installed in a traveling power transmission path, and that is activated for braking by hydraulic action and released by spring action. In addition to providing a brake for shaft braking, a plurality of fork shafts to which a plurality of shift forks for operating the mechanical transmission are fixed, each of which is aligned at the neutral position of these fork shafts, and for supplying hydraulic oil to the brake. A traveling power transmission device for an agricultural tractor or the like, characterized by forming a refueling hole connecting a hydraulic pump and the brake. 2. Claim 1 of claim 1 for registration of a utility model, characterized in that the brake is connected to an operating part of a main clutch of an agricultural tractor, etc. in such a way that hydraulic pressure applied to the brake is unloaded when the main clutch is disengaged. A traveling power transmission device for an agricultural tractor or the like as described in . 3. Utility model registration claim 1 or 2, characterized in that a relief circuit into which a pressure regulating valve for setting the hydraulic pressure applied to the brake is inserted is led to a lubricated part of the mechanical transmission. A traveling power transmission device for an agricultural tractor or the like according to item 2.