JPS607231Y2 - Traveling power transmission device for agricultural tractors, etc. - Google Patents

Description

[Detailed description of the invention] This invention facilitates the gear shifting operation of the mechanical transmission in an agricultural tractor or the like in which a hydraulic clutch type transmission and a mechanical transmission are connected in series. This article relates to a traveling power transmission device with a novel design.

As shown in Japanese Patent Application Laid-Open No. 53-45830, the applicant of the present application has previously proposed that, in agricultural tractors and the like as mentioned above, a hydraulic clutch in a hydraulic clutch type transmission device is arranged at the end of a transmission shaft to which a hydraulic clutch is mounted. A brake plate is mounted on the transmission shaft so as to be slidable but not relatively rotatable, and is positioned facing the fixed housing surface, and a brake plate is mounted on the transmission shaft on the opposite side of the fixed housing surface. Pistons located facing each other,
a compression spring disposed on the reciprocating rod and urging the brake plate to move in a direction in which it comes into pressure contact with the fixed housing surface via the piston; and a pressure oil chamber for resisting the force of the compression spring and displacing the piston. The above-mentioned pressure oil chamber is connected to the oil supply circuit for the hydraulic clutch, and the above-mentioned advancing/retracting rod is used as a main clutch operating means, and the advancing/retracting rod is engaged with the compression spring when the main clutch is disengaged. The present invention has developed a traveling power transmission device which has an interlocking connection so that it can be displaced in the direction of releasing the biasing action of the compression spring.

The above-mentioned brake plate is configured such that when the hydraulic clutch type transmission is in a transmission state, the hydraulic pressure applied to the hydraulic clutch in the transmission is applied to the pressure oil chamber, and the piston is moved away from the brake plate. Since it is displaced, no braking action is performed.

However, when the hydraulic pressure applied to the hydraulic clutch in a hydraulic clutch transmission is released to bring the transmission into a neutral state, the compression spring applies braking via the piston by releasing the hydraulic pressure to the pressure oil chamber. The plate is brought into pressure contact with the housing surface of the stationary nozzle, and the above-mentioned braking of the transmission shaft is effected with a relatively small braking force.

For this reason, when the hydraulic clutch type transmission is in a neutral state, the hydraulic clutch of the transmission will be slightly rotated by the constant rotational torque transmitted to the transmission from the engine or the direction of the wheels that are about to rotate automatically on a slope. This eliminates the inconvenience that unexpected power transmission occurs when the clutch is engaged due to the engagement force.

In addition, in the above-mentioned traveling power transmission device, the urging action of the above-mentioned compression spring is released in conjunction with the disengaging operation of the main clutch, that is, the braking action of the brake plate to which the braking force is applied by the compression spring is The purpose of releasing this is to facilitate the gear shifting operation of the mechanical transmission.

That is, this shift operation is performed after disengaging the main clutch, but at this time, the hydraulic pump for supplying oil to the hydraulic clutch of the hydraulic clutch type transmission is stopped, so the hydraulic pressure to the pressure oil chamber is reduced. When the action is released, the brake plate performs a braking action.

At that time, the rotating bodies in the mechanical transmission will also be in a braked relationship, so if the gear shifting rotating bodies that are mechanically engaged with each other due to gear meshing etc. are not in the correct holding position, they will be able to move to the correct engaged position. Since the brake cannot be rotated and the gear shift operation becomes difficult, the brake was designed to be released in conjunction with the main clutch operation.

As described above, there are still other factors that make it difficult to perform a gear shifting operation with a mechanical transmission.

That is, when the main clutch is disengaged prior to performing this gear shifting operation, the primary valve that controls the gear stage of the hydraulic clutch type transmission remains in one of the operating positions, and the hydraulic pressure corresponding to the operating position is maintained. Since hydraulic oil is not actively drained from the hydraulic clutch of a clutch-type transmission, a slight clutch engagement state persists, creating resistance to rotation, and this resistance also applies to the rotating body of a mechanical transmission. This is because it works.

In particular, as shown in Japanese Unexamined Patent Publication No. 52-131065, a one-way clutch is installed in a hydraulic clutch type transmission, which engages as the vehicle moves forward even when the engine is stopped, making it easier to start the engine. If it is attached, it will be large.

In other words, since such a one-way clutch has the function of interlocking and connecting two transmission shafts in a hydraulic clutch type transmission with the rotation of the driven-side transmission shaft, this one-way clutch is associated with a hydraulic pressure. If a hydraulic clutch other than the clutch maintains a slight clutch engagement state as described above even after the main clutch disengages, both the part of the hydraulic clutch that maintains this clutch engagement state and the one-way clutch part mentioned above This is because the two transmission shafts are interlocked and connected, and the transmission shaft becomes unable to rotate due to the interlocking connection between the two parts having different gear ratios.

This invention aims to provide a novel running power transmission device for agricultural tractors, etc., which has a simple structure that skillfully utilizes the braking mechanism described above, and which eliminates the above-mentioned disadvantages.

Regarding the illustrated embodiment, the configuration of the traveling power transmission device according to the invention will be explained. As shown in FIG. At 2a, the power is transmitted to the inside of the rear housing 5 through the clutch housing 2 containing the main clutch 3 and the transmission case 4, and drives the left and right rear wheels 6 to cause the aircraft to travel. In the constructed agricultural tractor, this invention is implemented as follows.

That is, as shown in FIG. 2, in the illustrated agricultural tractor, a hollow drive shaft is provided on the drive shaft 8 that transmits the power of the engine 1 toward the PTO shaft 7 (FIG. 1), which extends toward the rear of the machine body. 9 and a power shift shaft (transmission shaft) 10 disposed below, a hydraulic clutch type transmission 1 serving as a main transmission for traveling power is disposed at the front inside the mission case 4.
1, and is connected in series to this hydraulic clutch type transmission 11 to connect the power shift shaft 10 and the transmission shaft 12 disposed on an extension thereof with an appropriate gear ratio. A mechanical transmission 13, which is a traveling power sub-transmission, is provided at the rear inside the mission case 4.

For convenience of explanation, the structure of the hydraulic clutch type transmission 11 will be described first.As shown in FIG.
4, the F2 speed change gear 15, the F3 speed change gear 16 and the R speed change gear 17, and the R intermediate gear, which is loosely fitted onto the power shift shaft 10 and directly connected to the corresponding speed change gears 14-17 on the hollow drive shaft 9; F1 idler gear 18, F2 idler gear 19, F3 idler gear 20 and R, which are indirectly meshed through 17a.
The free rotating gear 21 and each free rotating gear 1 on the power shift shaft 10
F□hydraulic clutch 22, F arranged at 8-21
2 hydraulic clutch 23, F3 hydraulic clutch 24, and R hydraulic clutch 25.

In this hydraulic clutch type transmission 11, a hydraulic pump 26 driven by a hollow drive shaft 9 selectively supplies an operating shaft to each hydraulic clutch 22-25, and the F1 idle gear is driven by the operation of the F1 hydraulic clutch 22. 18 to power shift shaft 10
The F2 idler gear 19 is coupled to the power shift shaft 10 by actuation of the F2 hydraulic clutch 23 to shift the gear ratio F1 for the first forward speed.

By the operation of the F3 hydraulic clutch 24, the F3 idler gear 20 is connected to the power shift shaft 10 to set the gear ratio F3 for forward three speeds, and by the operation of the R hydraulic clutch 25, the R idler gear 21 is connected to the power shift shaft 10. By combining the two, it is possible to selectively obtain the gear ratio R for the first reverse speed.

A spacer plate 27 is sandwiched between the clutch housing 2 and the transmission case 4, and the above-mentioned hydraulic pump 26 is mounted on the clutch housing 2 on the hollow drive shaft 9 with the pump case attached to the front face of the spacer plate 27. It is located at the rear end of the inside.

FIG. 3 shows a hydraulic circuit that controls the operation of the hydraulic clutch type transmission 11, including an oil supply circuit 29 that guides hydraulic oil from the oil tank 28 toward the hydraulic clutches 22-25 by the hydraulic pump 26, and the hydraulic clutch 22-25. A switching valve 31 as shown, that is, a full hydraulic clutch 22-25, is connected to an oil drain circuit 30 that guides hydraulic oil from the 25 direction to the oil tank 28.
In addition to the neutral position N in which the hydraulic clutches 22, 23, 24, or 25 are inactive, hydraulic oil is selectively supplied to one hydraulic clutch 22, 23, 24, or 25, and oil is drained from the other three hydraulic clutches. 1
The switching valve 3 has four operating positions: speed position F1, forward second speed position F2, forward third speed position F3, and reverse first speed position R.
1 is a provision.

The hydraulic pressure of the hydraulic oil supplied to the hydraulic clutches 22-25 is
It is set by the pressure regulating valve 32.

As shown in FIG. 4, from inside the mission case 4,
A seal housing 33 attached to the front surface of the intervening plate 27 is fitted onto the front end of the power shift shaft 10, which passes through the clutch housing 2 and extends into the clutch housing 2.

A plurality of annular grooves formed in the front end of the power shift shaft 10 form a plurality of oil distribution chambers 34F1. 34F2.34
F3. 34R is formed in the seal housing 33, and the hydraulic oil led from the hydraulic pump 26 via the switching valve 31 is once led into this oil distribution chamber 34, and from there to the inside of the power shift shaft 10. It is led to each hydraulic clutch 22-25 via an oil path (not shown).

Note that, as described later, the switching valve 31 is built in the seal housing 33.

Similarly, as shown in FIG. 4, a flat notch 10a is formed near the front end of the power shift shaft 10, and a brake plate 35 is mounted on the power shift shaft 10 using this flat notch 10a. , which cannot rotate relative to the shaft 10 but is slidably mounted thereon.

This brake plate 35 is positioned facing a brake surface (fixed housing surface) 36 formed by a step on the inner surface of the seal housing 33.

A piston 37 is provided on the opposite side of the braking surface 36 and is fitted into the seal housing 33.
The seal housing 3 is positioned facing the brake plate 35.
Rotation is prevented by inserting a pin 38 supported by the housing lid 33a of No. 3 into the hole of the piston 37.

A retractable rod 39 is arranged concentrically with the piston 37 on the housing lid 33a and is slidably supported thereon.A head 39a at the tip and a housing lid 3 are mounted on the retractable rod 39.
A compression spring 40 is provided between the inner surface and the inner surface.

The piston 37 is shaped to have a step in the middle, and at this step, a pressure oil chamber is provided within the seal housing 33 for moving the piston 37 backward (forward in the longitudinal direction of the aircraft). 41 is in full form.

In particular, an oil passage 43 that communicates this pressure oil chamber 41 with a space 42 in the housing lid 33a is formed in the piston 37.

This oil passage 43 is opened in the space 42 at the center of the piston 37, but the opening end of the oil passage 43 is formed in a tapered hole 43a.
A ball 44 is formed in the tapered hole 43a.
is inserted and rests on the tip surface of the retractable rod 39.

Further, the above-mentioned pressure oil chamber 41 is connected to a connection circuit 45 shown in FIG.
It is connected to the oil supply circuit 29 described above.

As described above, the compression spring 40 moves and biases the brake plate 35 via the ball 44 and the piston 37 in the direction in which the brake plate 35 comes into pressure contact with the brake surface 36 .

However, when the switching valve 31 is set to either operating position F1. F2. F3
Alternatively, in R, when the hydraulic clutch type transmission 11 is performing gear change transmission, the oil pressure set by the pressure regulating valve 32 acts from the oil supply circuit 29 to the compression chamber 41 via the connection circuit 45, Since the piston 37 is moved backward against the force of the compression spring 40, the brake plate 35 is not pressed against the brake surface 36, and the brake plate 35 does not brake the power shift shaft 10.

Further, in this state, the ball 44 comes into close contact with the surface of the tapered hole 43a due to the force of the compression spring 40, blocking the oil passage 43.

When the switching valve 31 is moved to the neutral position N and the hydraulic clutch type transmission 11 is placed in the neutral state, the oil supply circuit 29 is directly connected to the oil drain circuit 30, and the oil pressure in the oil supply circuit 29 is released. , the hydraulic pressure in the pressure oil chamber 41 is also released, and the braking plate 35 is brought into pressure contact with the braking surface 36 by the biasing action of the compression spring 40 and becomes unrotatable, and the power shift shaft, which cannot rotate relative to the braking plate 35, 10 brakings are performed.

Therefore, when the hydraulic clutch type transmission 11 is in the neutral state, the problem that the hydraulic clutches 22-25 are unexpectedly engaged due to the rotational torque acting on the transmission 11 does not occur.

Note that even in this state, the oil passage 43 is blocked by the ball 44.

The advancing/retracting rod 39 is pulled out toward the front of the aircraft body while engaging the compression spring 41 at the head 39a in conjunction with the disengagement operation of the main clutch 3, so as to release the biasing action of the compression spring 41. being done.

To explain the mechanism for this purpose, as shown in FIGS. 4 to 6, a pin 46 extending along the transverse direction of the body is fixed to the base end of the retractable rod 39 facing outside the housing lid 33a.

Further, an operating shaft 47 is provided which is supported on one side wall of the clutch housing 2 and is rotatable around an axis.The above-mentioned pin 4
6 is provided with a pair of left and right operating arms 48a that engage from the rear side of the fuselage.

The main clutch 3 is normally disengaged by depressing a main clutch pedal 50 rotatably supported around a fulcrum shaft 49, and the bearing sleeve disengages the main clutch 3 by sliding displacement. 51 and the main clutch pedal 50 are interlocked and connected as shown in FIG.

That is, the pedal arm 50a of the main clutch pedal 50 is fixed to the rotating cylinder 52 on the fulcrum shaft 49, and the rotating arm 53 is also fixed, and the pedal arm 53 is fixed to the end of the operating shaft 54 extending in the transverse direction of the fuselage. The rotary arm 55 and the rotary arm 53 are connected by a forward and backward lever 56, and a shifter 57 that engages with the bearing sleeve 51 is fixed to the operating shaft 54, and when the main clutch pedal 50 is depressed, The above series of operating mechanism members 50a, 52, 5
3, 56, 55, 54° 57 to advance the bearing sleeve 51 to obtain disengagement of the main clutch 3.

The operating shaft 47, which is related to the forward/retractable lever 39, has a rotating arm 59 fixed to the operating shaft 47 with a pin 58 outside the clutch housing 2, and a rotating arm 59 that is fixed to the operating shaft 47 with a pin 58.
and a retractable lever 6 whose both ends are pivoted to the above-mentioned rotating arm 55.
0 and the pivot arm 5 in the main clutch 3 operating mechanism.
It is connected to 5.

As described above, when the rotating arm 55 is rotationally displaced in the direction of disengaging the main clutch 3, the advancing/retracting rod 60 and the rotating arm 5
9, the operating shaft 47 is rotationally displaced in the direction of arrow C in FIG.
a pushes the pin 46 and displaces it forward, and this pin 3
9 is fixed so that the retractable lever 39 can be pulled out.

Note that the advance/retreat rod 60 in the connection mechanism is provided with an adjustment portion 60a that enables timing adjustment by adjusting its length.

Therefore, when the main clutch 3 is disengaged by depressing the main clutch pedal 50, the advance/retreat lever 39 is moved toward the head 39.
It is pulled out while tightening the spring 40 at point a, and the biasing action of the compression spring 40 on the ball 44, the piston 37, and the brake plate 35 is released.

Therefore, when the main clutch 3 is disengaged, not only the braking of the power shift shaft 10 by the brake plate 35 is released, but also the hydraulic pressure in the pressure oil chamber 41 has no urging effect on the ball 44, and the ball 44 is Since it can be freely displaced in the direction of extraction from the hole 43a, it is immediately released.

As a result, the oil supply circuit 2 connected to the pressure oil chamber 41
9, and therefore also from the l hydraulic clutches 22, 23, 24 or 25 which were previously operated and which are connected to the oil supply circuit 29 via the switching valve 31, the main clutch 3 is released. This will be done promptly upon departure.

That is, the oil passage 43, the ball 44, and the compression spring 40 are connected to the following unload valve 61, that is, the oil supply circuit 29 as shown in FIG. When the main clutch 3 is disengaged, it takes the operating position I, and when the main clutch 3 is disengaged, it takes the unloading operating position ■.
23, 24 or 25 constitute an unload valve 61 for unloading hydraulic pressure.

As shown in FIG. 2, a one-way clutch 62 is interposed between the F3 free rotating gear 20 and the power shift shaft 10.

When this one-way clutch 62 is driven in a relatively forward rotation direction from the power shift shaft 10 side, it engages with the F
The three free rotating gears 20 are coupled to the power shift shaft 10.

When the F□ hydraulic clutch 22 or the F2 hydraulic clutch 23 is activated, the power shift shaft 10 rotates in the normal direction, but since the F3 idle gear 20 rotates in the normal direction at a higher rotation speed than the power shift shaft 10, the one-way clutch is activated. 62 is relatively driven in normal rotation from the F3 idler gear 20 side, and is not engaged with the clutch, thereby causing no inconvenience in speed change transmission.

When such a one-way clutch 62 is provided, even when the engine 1 unexpectedly stops or when the capacity of the battery for starting the engine 1 decreases, normal rotation of the power shift shaft 10 by moving the vehicle forward will be effective. Since the directional clutch 62 is engaged and the F3 idler gear 20 is coupled to the power shift shaft 10, and the transmission path is not cut off at the hydraulic clutch type transmission 11, the engine 1 can be easily started. It becomes possible.

Next, the configuration of the mechanical transmission 13 described above will be explained with reference to FIG. 2. A hollow transmission shaft 63 is provided on the drive shaft 8 in the rear half of the mission case 4.
This hollow transmission shaft 63 is connected to the power shift shaft 10 in a deceleration manner by meshing a large diameter gear 65 at the base end with a small diameter gear 64 at the end of the power shift shaft 10 .

On the hollow transmission shaft 63, there are three speed change gears 66, 67, 6.
8 is fixedly provided.

Further, outside the hollow transmission shaft 63, there may be provided a creep gear shift gear 69 which is interlocked and connected to the smallest diameter shift gear 66 among the shift gears 66-68 via a gear reduction device (not shown). be.

Furthermore, on the transmission shaft 12, there are a shift gear 70 that can mesh with the transmission gears 69 and 66, a shift gear 71 that can mesh with the transmission gear 67, and a shift gear 72 that can mesh with the transmission gear 68. A shift gear 72 having a pawl 72a that can engage with a pawl 10a formed at the end of the shift shaft 10 is provided so as to be slidable only.

As described above, the mechanical transmission 13 has shift gears 70, 7.
1.72 is selectively slidably displaced on the transmission shaft 12, the meshing between the gears 69 and 70 sets the creep gear ratio, and the meshing between the gears 66 and 70 sets the 1st speed gear ratio. The gear ratio of 2nd speed is determined by meshing between gears 67.71 and 68.7.
The gear ratio of the 3rd speed is determined by the meshing between the two shafts, and the gear ratio of the 4th speed is determined by the coupling between the shafts 10 and 11 by the meshing of the pawls 10a and 72a.
Each can be obtained selectively.

Next, in the illustrated agricultural tractor, the switching valve 31 for switching the gear stage of the hydraulic clutch type transmission 11 is particularly built into the seal housing 33, so although it is a part unrelated to this invention, Let me briefly explain,
FIG. 7 shows the housing lid 33a of the seal housing 33.
2 is a front view of the spacer plate 27, the seal housing 33 thereon, and the case body 73 of the pump 26 with the pump case M26a (FIG. 2) of the pump case of the hydraulic pump 26 removed. .

As shown in FIGS. 7 and 8, the seal housing 33 includes:
A valve hole 75 extending in the front-rear direction is formed near the support hole 74 of the power shift shaft 10, and a spool 76 is fitted into the valve hole 75 to form the switching valve 31.

The tip of the spool 76 is connected to a hole 77 in the housing lid 33a.
Detent grooves 78N, 7 formed at the tip by fitting into the
8F□, 78F2, 78F3゜78R and a pair of balls 7
9 and the spring 80 constitute a detent means.

The base end of the spool 76 faces into the mission case 4, and the spool 76 is connected to the main shift lever 82 (on the mission case 4) via a link mechanism 81, a part of which is shown in FIGS. (Fig. 1) direction.

On the back side of the spacer plate 27, there is a groove 2 where a part of the link mechanism 81 faces.
This is an imitation of 7a.

The valve hole 75 is connected from the discharge port 26b of the hydraulic pump 26 through an oil passage 83 formed between the spacer plate 27 and the seal housing 33.
Pressure oil is introduced into the switching valve 31.

From here, oil passages 84F□, 84F2, 84F3 lead hydraulic oil to the bearing hole 74 or the oil distribution chamber 34 (Fig. 4).
=84R is formed on the seal housing 33.

These oil passages 84F, 84F2. 84F3-8
4R, at least in their distal end portions, respectively, have oil distribution chambers 34F□, 34F2. The position of the 34F3 and 34R in the longitudinal direction of the aircraft is the same, making it easier to control the 84-type oil passage.

In FIG. 7, 84D is a drain oil passage led from the valve hole 75 position.

Further, in FIGS. 4 and 7, reference numerals 85 and 86 denote lubricating oil passages formed between the intervening plate 27 and the seal housing 33, which open into the space 42 as shown in FIG.

The lubricating oil is supplied from within the space 42 to the front end oil chamber 88 of the power shift shaft 10 via an oil passage 87 formed in the piston 37.
An oil passage (not shown) in the power shift shaft 10
is led to hydraulic clutches 22-25 via.

In FIG. 1, 89 is the shift gear 70°71.7
2 (FIG. 2) is a gear shift lever that changes the gear stage of the mechanical transmission 13, and 90 is a PTO transmission lever that operates a PTO transmission (not shown) provided in the rear part of the rear housing 5. It is.

The illustrated traveling power transmission device has the following advantages.

That is, the advantages are based on the braking action by the brake plate 35, and the main clutch 3 prior to the gear shifting operation of the mechanical transmission 13.
The advantage based on the fact that the braking action of the brake plate 35 is released by the disengagement operation is as explained above.
Note that other valve bodies such as a poppet may be used in place of this ball.

), the blocking function of the oil passage 43 is released, and the pressure oil chamber 4
3, and thus the oil pressure of the oil supply circuit 29, is released very quickly.

Therefore, even if the switching valve 31 is in the first forward speed position F1 or the second forward speed position F2, the F hydraulic clutch 22
Alternatively, the hydraulic pressure from the F2 hydraulic clutch 23 is released very quickly.

This means that when the main clutch 3 is disengaged and the mechanical transmission 13 is then operated to change gears using the sub-shift lever 89, the operation can be performed easily.

That is, as stated at the beginning, it is F that the shafts 9 and 10 are connected in both the transmission path for the 3rd forward speed equipped with the one-way clutch 62 and the transmission path for the 2nd forward speed for the 1st forward speed.
1 hydraulic clutch 22 or F2 hydraulic clutch 23 no longer occurs, so that the mutually meshed rotating bodies 66, 67, 6 in the mechanical transmission 13
This is because even when B, 69, 10a and 70.71, 72.72a are not in the correct meshing posture, rotation to the correct meshing posture is easily performed when the gears 70, 71, 72 are shifted.

In this way, the running power transmission device under consideration is designed to facilitate the speed change operation of the mechanical transmission 13, and the mechanism for this purpose is a braking mechanism equipped with a braking plate 35 and a main clutch 3. A mechanism for releasing the brake by the brake mechanism in conjunction with the disengagement operation is skillfully utilized to provide the piston 37 in the brake mechanism with an oil passage 43 for releasing the hydraulic pressure from the pressure oil chamber 41 of the mechanism. In this way, this oil passage is blocked by a valve body 44 which is moved and energized by a compression spring 40 in the brake mechanism, and the above-mentioned brake release mechanism directly releases hydraulic pressure in conjunction with disengagement of the main clutch. Since it is configured to act as an operating mechanism, it has an extremely simple structure.

In other words, the hydraulic release mechanism is constructed using a brake mechanism and has a simple structure, and the hydraulic release operation mechanism is constructed from the existing brake release mechanism itself. Despite these advantages, the structure is extremely simple.

[Brief explanation of the drawing]

Figure 1 is a side view of an agricultural tractor equipped with an embodiment of this invention, Figure 2 is a longitudinal side view of the main parts of the same tractor, Figure 3 is a circuit diagram of the hydraulic circuit in the same embodiment, and Figure 4 is a side view of an agricultural tractor equipped with an embodiment of this invention. FIG. 5 is a partially cutaway side view of the main parts of the tractor, FIG. 6 is a longitudinal front view of only the main parts of the same embodiment, and FIG. 7 is a longitudinal sectional side view of the main parts of the tractor. FIG. 8 is a front view of only the main parts of the tractor, and FIG. 8 is a longitudinal sectional side view of the main parts of the tractor. 3...Main clutch, 9...Hollow drive shaft, 10...Power shift shaft (transmission shaft), 10a
...Flat cutout, 11...Hydraulic clutch type transmission, 12...Transmission shaft, 13...
・・Mechanical transmission, 22, 23, 24, 25...
... Hydraulic clutch, 26 ... Hydraulic pump, 27
...Interval plate, 29...Oil supply circuit, 30.
...Oil drain circuit, 31...Switching valve, 33.
... Seal housing, 33a ... Housing lid, 35 ... Brake plate, 36 ...
Braking surface (fixed housing surface), 37...Piston, 39...Advancing/retracting rod, 39a...Head, 40...Compression spring, 41... ...Compression chamber, 43...Oil path, 43a...Tapered hole, 44...Ball, 45...Connection circuit, 46... ... Zen, 47 ... Operation axis, 4
8... Actuation hardware, 48a... Actuation arm, 50... Main clutch pedal, 55... Bent rotation arm, 59... Rotation arm, 60...
・Advance/retreat bar.

Claims (1)

[Scope of utility model registration request] In agricultural tractors etc. in which a hydraulic clutch type transmission and a mechanical transmission are connected in series, the hydraulic clutch in the hydraulic clutch type transmission is placed at the end of the transmission shaft on which the hydraulic clutch is mounted, and the hydraulic clutch is installed on the transmission shaft. A brake plate that cannot be relatively rotated but is slidably mounted and is located facing the fixed housing surface, and a piston that is located facing this brake plate on the opposite side of the fixed housing surface, and the piston moves forward and backward. a compression spring disposed on the rod and biasing the brake plate in a direction that presses the brake plate against the fixed housing surface via the piston, and pressure oil for resisting the force of the compression spring and displacing the piston. The pressure oil chamber is connected to the oil supply circuit for the hydraulic clutch, and the advance/retreat lever is used as a main clutch operating means, and the advance/retreat lever is engaged with the compression spring when the main clutch is disengaged. The driving power transmission device is an interlocking connection so that the piston is displaced in a direction to release the biasing action of the compression spring, and the piston is formed with an oil passage for releasing the hydraulic pressure in the pressure oil chamber. A traveling power transmission device characterized in that the oil passage is blocked by a valve body moved and biased by the compression spring.