JPS5925694Y2 - Agricultural tractor PTO device lubrication mechanism - Google Patents

Description

[Detailed description of the invention] The present invention relates to a lubrication mechanism between a PTO transmission shaft and a constantly meshing gear supported by the PTO transmission shaft when a multi-stage PTO (power take-off) transmission mechanism is arranged in the upper part of a transmission case in an agricultural tractor. .

The PTO shaft, which applies rotational force to a work machine towed by a tractor, generally protrudes rearward from the rear end of the transmission case (including the rear axle case), and can be shifted to two stages at the rear end of the transmission case. has already been widely adopted.

However, in that case, the PTO transmission is located at the rear end of the transmission case, so the operating mechanism (levers, rods, etc.) becomes complicated in order to be able to remotely control it from the cockpit, and an increase in the required operating force is unavoidable. do not have.

Furthermore, since the number of gears is small, it may not be possible to provide the optimum rotation to the working machine.

As a countermeasure for this, the applicant has focused on the fact that a group of multiple main transmission gears (for example, 1st gear, 2nd gear, 3rd gear, reverse gear, etc.) are fixed to the main shaft above the power shift transmission. , has already proposed a system in which a PTO transmission shaft is disposed above it to form a PTO transmission mechanism, and a PTO transmission lever is provided above the power shift transmission, that is, near the cockpit (Utility Model Publication No. 57-40384). Publication No.).

However, in that case, the PTO transmission shaft occupies a high position, and the constantly meshing gear such as a helical gear rotates above it, so it is necessary to splash a sufficient amount of oil onto the sliding surface between the PTO transmission shaft and the constantly meshing gear above it. It is difficult to apply the oil, and it is easy to cause poor lubrication.

In order to solve the above problem, the present invention provides an oil passage within the PTO transmission shaft for lubricating the constantly meshing gear rotatably supported on the PTO transmission shaft, and connects this oil passage to the relief valve of the power shift transmission hydraulic system. It is characterized by being connected to a relief oil line from the tank to the tank.

In particular, if the switching valve spool and pressure regulating valve (relief valve) for switching the hydraulic clutch (power shift clutch) in the power shift transmission are built into the center plate sandwiched between the clutch housing and the power transmission case, The space above the transmission case where the switching valve etc. was installed is now available, so the PT can be installed there.
It becomes easy to install the O transmission, and the connection of the lubricating oil passage becomes extremely simple.

Next, it will be explained with reference to the drawings.

In FIG. 1, which is a schematic diagram of the longitudinal left side of the power transmission system, there is a center plate 3 sandwiched between the clutch housing 1 and the transmission case 2, and the main components of the power shift transmission 5 on the rear wall 4 of the transmission case 2. A main shaft 6, a clutch shaft 7, and a PTO transmission shaft 9, which is a main component of a PTO transmission mechanism 8, are supported via bearings. ).

Also, the PTO transmission shaft 10, which is disposed at the rear of the main shaft 6 (on the right side in Fig. 1), protrudes rearward from the rear wall of the submission case 11 (or rear axle case).
Connect to the TO shaft.

The traveling transmission shaft 12 behind the clutch shaft 7 is
It is connected to the clutch shaft 7 directly or via the sub-transmission in the submission case 11, and the traveling transmission shaft 12
A bevel gear 13 at the rear end meshes with a ring gear 14 of a rear axle drive differential mechanism.

On the main shaft 6 are reverse main transmission gears 16 and 17, a first
The second and third consecutive main transmission gears 18, 19, and 20 are fixed, and the reverse gear 17 is engaged with the clutch gear 23 of the reverse power shift clutch 22 via the idle gear 21, and the reverse gear 17 is engaged with the clutch gear 23 of the reverse power shift clutch 22. When hydraulic pressure is supplied to the power shift clutch 22 through a road (not shown) and the clutch 22 is connected, the clutch gear 23 is integrated with the clutch shaft 7 and the reverse rotation is transmitted to the clutch shaft 7. There is.

The first gear 18 is connected to the first continuous power shift clutch 24.
When hydraulic pressure is supplied to the power shift clutch 24, the clutch 24 is connected, the clutch gear 25 is integrated with the clutch shaft 7, and the rotation of the first series is transmitted to the clutch shaft 7.

26.27 is the power shift clutch for 2nd and 3rd speed, 2
8.29 is the clutch gear for 2nd speed and 3rd speed,
The operation of both clutches 26 and 27 is similar to that of clutch 24.
be.

On the PTO transmission shaft 9 are PTO transmission gears 31, 32, 3.
3゜34 are held in a non-slidable state and are rotatable, and these are sequentially connected to gears 16, 18, 19゜2 on the main shaft 6.
It is always meshing with 0.

A gear 35 fixed to the rear end of the PTO transmission shaft 9 constantly meshes with a gear 36 fixed to the front end of the PTO transmission shaft 10.
The rear end of the main shaft 6 is rotatably supported within a bearing hole 37 at the front end of the PTO transmission shaft 10.

The PTO transmission gear 31 is integrally equipped with spline external teeth 38, and the spline external teeth 38 are connected to the coupling sleeve 3.
9, the cup non-ge sleeve 39 is slidably spline-fitted onto a bub 41 fixed on the PTO transmission shaft 9.

Therefore, when the coupling sleeve 39 is shifted in the direction of arrow A and its internal teeth 40 mesh with the spline external teeth 38, the rotation of the gear 31 is transmitted to the PTO transmission shaft 9 through the coupling knob 39 and the bub 41. From there, the signal is transmitted to the PTO transmission shaft 10 through gears 35 and 36, and the PTO first speed is obtained.

The gear 32 is integrally equipped with spline external teeth 42, and when the coupling sleeve 39 is shifted in the reverse A direction, the internal teeth 40 are
When engaged with the external teeth 42, PTO second speed is obtained.

43 and 44 are spline external teeth, 45 is a coupling sleeve, and 46 is a buff. When the coupling sleeve 45 is shifted in the direction of arrow A and meshed with the external teeth 43, PTO 3rd gear is activated, and 45 is a coupling sleeve, and 46 is a buff. When the gear is shifted to the outer tooth 44 and engaged with the outer tooth 44, the fourth PTO speed is obtained.

When the coupling sleeves 39 and 45 are in the neutral position shown in the drawing, each PTO transmission gear 31 to 34 rotates on the PTO transmission shaft 9 at a different rotation speed, and the PTO
Friction occurs between the transmission shaft 9 and the transmission shaft 9.

When one of the cup nonge sleeves 39, 45 is shifted in the direction of arrow A or reverse A to switch to an arbitrary PTO gear, the remaining three PTO gears similarly come into frictional contact with the PTO gear shift shaft 9.

Since the PTO transmission shaft 9 is located above the power shift transmission 5 as described above, it is difficult to splash a sufficient amount of oil onto the frictional portion.

Therefore, in the present invention, the power shift clutch 22.2
A forced lubrication method is adopted that uses unnecessary oil in the hydraulic system to operate the 4.26.27.

An oil pump 48 driven by a main shaft 6 is attached to the front surface of the center plate 3, and the discharge port of the oil pump 48 is connected to a pressure regulating valve 50 (IJIJ valve) through an oil passage 49 inside the center plate 3. , pressure regulating valve 50
The outlet of the spool 52 is connected to the switching valve spool 52 supported by the center plate 3 through an oil passage 51, and the outlet of the spool 52 is connected to the oil passages 53 to 56 and the corresponding oil passage in the clutch shaft 7 (not shown). ) and sequentially power shift clutch 22
．． Connect on 24.26.27.

The switching valve spool 52 protrudes upward so that it can be operated from above the center plate 3, and by operating the spool 52, any power shift clutch 22, 24, 26
．． 27 can be connected to obtain a desired gear position.

A relief oil passage 57 of the pressure regulating valve 50 is connected to a tank 59 (inside the transmission case 2) through a check valve 58, and an oil passage 60 branched from the relief oil passage 57 is connected to an oil passage 61 in the PTO gear shift shaft 9. (Fig. 2).

In FIG. 2, the front end of the PTO gear shift shaft 9 is fitted into a bottomed hole 62 provided in the center plate 3, and an O tank 63 maintains the liquid tightness of a chamber 64.
1 is connected.

The oil passage 61 extends vertically within the shaft 9, from which oil passages 65 to 68 in the perpendicular direction branch off, and each oil passage 65 to 68 is sequentially connected to the PT.
It opens at the inner periphery of the O transmission gears 31-34.

69 is a bush or needle bearing, and an annular oil reservoir 70 is formed between the bushes.

71 and 72 are keys, 73 is a collar, and 74 is a bearing.

During operation, the oil pressure of the relief oil discharged from the pressure regulating valve 50 (FIG. 1) is maintained at a low constant value by the check valve 58.

This oil passes through the oil passage 60.61°65-68 to the PTO
It is forcibly supplied to the sliding parts of the transmission gears 31 to 34 and the PTO transmission shaft 9.

As explained above, according to the present invention, in order to utilize the relief oil that is not used for the operation of the power shift clutch 22, 24, 26, 27, the relief oil passage 57 is connected to the oil passages 61.65 to 61 in the PTO transmission shaft 9. Pass through PTO transmission gears 31 to 34
Since it communicates with the inner peripheral part of the PTO gear shift shaft 9.
Even though it is disposed above the power shift mission 5, reliable lubrication is possible.

In addition, by incorporating the pressure regulating valve 50, switching valve spool 52, etc. in the center plate 3, it is easy to obtain a space in the upper part of the transmission case to incorporate the PTO transmission mechanism 8, and the relief oil passage 57 in the center plate 3 and the PTO transmission mechanism 8 can be easily obtained. The oil passage 61 of the shaft 9 can be connected without using piping.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal left side view of the drive system of an agricultural tractor to which the present invention is applied, and FIG. 2 is an enlarged sectional view of a part of FIG. 1. 5...Power shift mission, 6...
・Main shaft, 8...PTO transmission mechanism, 9...
・PTO transmission shaft, 10...PTO transmission shaft, 31
~34... Gear, 50... Pressure adjustment valve (relief valve), 57... Relief oil path, 5
9...Tank, 61.65-68...
Oil road.

Claims (1)

[Scope of utility model registration request] In a PTO device, the PTO transmission shaft is placed behind the main shaft of the power shift mission, and a constant-mesh PTO transmission mechanism is installed between the main shaft and the parallel PTO transmission shaft above it. PTO system lubrication for agricultural tractors in which an oil passage for lubricating the freely supported constantly meshing gear is provided inside the PTO transmission shaft, and this oil passage is connected to the relief oil passage from the relief valve of the power shift transmission hydraulic system to the tank. mechanism.