JPH0444432Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an inertial rotation prevention device for a power transmission system in a tractor.

(Prior Art) In the power transmission system of a tractor, a system in which a hydraulic brake is provided within a transmission case in order to prevent inertial rotation of the transmission shaft after the main clutch is disengaged is well known.

(Problems to be solved by the invention) Conventionally, in this type of device, a dedicated valve linked to the clutch pedal was provided independently, and this valve and the brake were connected via an oil path. It is necessary to secure space on the wall of the mission case to mount the valve.
Particularly, in the case where a relay gear box for steering is provided on the side wall of the transmission case, the relative position of the gear box and the valve becomes a problem, resulting in a disadvantage that the structure is complicated.

In view of these conventional problems, the present invention aims to simplify the structure by incorporating a valve into a steering gear box.

(Means for solving the problem) As a means for solving the problem, the present invention provides a brake 51 in the transmission case 4 to prevent inertial rotation of the power transmission system when the clutch 31 is disengaged, and In a tractor equipped with a steering case 19 outside the side wall 18, a piston ram 54 for actuating the brake 51 is provided in a cylinder chamber 56 formed in the side wall 18, and the steering case 19 is attached to the side wall 18 so as to cover the cylinder chamber 56. 19, and a valve 57 is incorporated into the steering case 19 for supplying pressure oil to the cylinder chamber 56 when the clutch 31 is disengaged and for removing pressure oil when the clutch 31 is engaged.

(Operation) When the depression force on the clutch pedal 25 is released, the valve shaft 61 of the rotary valve 57 is in the state shown in FIG. 4, and the notch 65 communicates the oil passage 59 with the through hole 64. Therefore, the piston ram 5
4 is pushed by a spring 55, and the oil in the cylinder chamber 56 is returned into the transmission case 4 through the oil passage 59, cutout 65, and through hole 64, and the brake shoe 52 is separated from the body 47A of the interlocking gear 47. ing.

When switching the gear transmission mechanism 41, the clutch pedal 25 is depressed one step to disengage the travel clutch 31. At this time, the clutch rod 29 moves forward in FIG. 6, so the lever 70, the rod 69,
The valve shaft 61 of the rotary valve 57 is rotated in the direction of the arrow in FIG. 4 via the lever 67, as shown in FIG. Therefore, the notch 6 of the valve shaft 61
3 communicates the oil passages 59 and 60, pressure oil is supplied to the cylinder chamber 56 through the oil passage 60 notch 63 and the oil passage 59, and the piston ram 54 moves in the direction of the arrow in FIG. 8 against the spring 55. Slide the brake shoe 5.
2 against the interlocking gear 47. This prevents the interlocking gear 47 from rotating in conjunction with the inertial rotation transmission shaft 39, and allows the gear transmission mechanism 41 to be easily switched.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In Fig. 6, 1 indicates the body of the tractor;
It consists of an engine 2 and a transmission case 4 connected to the engine 2 via a clutch housing 3.

The engine 2 is covered with a bonnet 5, and a hydraulic device 7 having a lift arm 6 is provided on the rear upper surface of the transmission case 4.

Reference numeral 8 denotes a steering device, which is composed of a steering wheel 9 and a driver's seat 10, and the steering wheel shaft 11 of the steering wheel 9 is erected so that it can be inserted into and removed from the receiving tubes 12A and 13A of the steering cases 12 and 13 arranged in the front and rear, respectively. The vehicle can be freely changed between a forward driving position (solid line in the figure) and a backward driving position (imaginary line in the figure).
Along with this, the driver's seat 10 can also be changed back and forth.

The respective output shafts of the steering cases 12 and 13 are interlocked and connected to the steering shaft 20 of a relay steering case 19 attached to the lower part of the side wall 18 of the vehicle body 1 by means of steering shafts 16 and 17 having universal joints 14 and 15, respectively. axis 20
This allows steering wheels (not shown) to be steered. Inside the relay steering case 19, a second
Bevel gears 21 that engage with each other as shown in the figure,
22, the bevel gear 21 is fixed to the steering shaft 16, and the bevel gear 22 is fixed to the steering shaft 20, respectively. Each steering shaft 16, 20 is supported by bearings 23, 24.

25 is a clutch pedal, which is provided on the left side of the vehicle body 1 so that it can be depressed freely against a return spring (not shown) about a pedal shaft 26, and which is connected to an arm 27 provided at the base of the pedal, and a clutch pedal that can freely swing back and forth in front of the arm 27 provided at the base of the pedal. By interlocking and connecting the provided clutch lever 28 with a clutch rod 29, a double clutch 30 built into the clutch housing 3 can be freely inserted and removed.

As shown in FIG. 7, the double clutch 30 consists of a traveling system clutch 31A and a PTO system clutch 32B, and when the double clutch 30 is engaged and disengaged, the power of the engine 2 is transferred to the propulsion shafts 33, 34, which have a double-internal and external shaft structure.
Intermittent.

That is, a clutch release structure (not shown) is interlocked with the clutch lever 28 so that when the clutch pedal 25 is depressed in one step, the drive system clutch 31A is first disengaged, and when the clutch pedal 25 is depressed in the second step, the PTO system clutch 32B is disengaged.

7 and 8, especially FIG. 7, of the propulsion shafts 33 and 34, the inner shaft 33 is for running and is supported by a bearing 35 on the rear wall 3A of the clutch housing 3. , 34, the outer shaft 34 is a cylindrical shaft and is fitted onto the inner shaft 33, and a bearing 37 is attached to a gear transmission case 36 of a middle structure mounted on the front side of the rear wall space 3A of the clutch housing 3. Supported by.

Inside the gear transmission case 36, a gear transmission mechanism 38 is provided.
is built-in, and the outer shaft 34 and the PTO transmission shaft 39 are interlocked and connected, and the PTO transmission shaft 39 passes through the rear wall 3A of the clutch housing 3 in the front-rear direction and extends rearward, or rightward in FIG. Clutch mechanism 40
It is linked to a PTO transmission mechanism (not shown) via.

41 is a gear transmission mechanism that can freely switch between forward and reverse directions;
A first gear 42 is fitted on the protruding end of the inner shaft 33 with a spline, a second gear 44 is fitted so as to be relatively rotatable on a traveling transmission shaft 43 installed on the same axis of the inner shaft 33, and The transmission body 45 is fitted with a spline on the front end of the transmission shaft 43, and the engaging portions 42A and 44A of the first gear 42 and the second gear 44, which are fitted with the spline on the transmission body 45, can be freely engaged and disengaged. It consists of a shift sleeve 46, an interlocking gear 47 interlocking with the first gear 42 and the second gear 44, an idle gear 48 interlocking with the interlocking gear 47 and the second gear 44, etc. .

This gear transmission mechanism 41 includes a transmission case 4
Inside, the clutch housing 3 is housed in a case 49 detachably attached to the rear wall 3A, and the soot 49 has a U-shape in longitudinal section and is open at its upper end.
Shift fork 50 that allows 6 to slide freely in the axial direction
is provided. Note that the traveling transmission shaft 43 is interlocked and connected to the traveling gear transmission mechanism M.

The interlocking gear 47 is fitted onto the PTO transmission shaft 39 and supported by a needle bearing 51 so as to be relatively rotatable, and the PTO transmission shaft 39 has the function of supporting the interlocking gear 47 in addition to transmitting power. The structure is simplified.

51 is a hydraulic brake that prevents inertial rotation and linked rotation of the interlocking gear 47. The shaft portion 52A of the brake shoe 52 is slidably supported on the side wall 49A of the case 49, and the arcuate shoe portion 52B is connected to the interlocking gear. 47, and can freely move toward and away from the outer peripheral surface of the body 47A, and reference numeral 53 indicates a return spring thereof.

54 is a piston ram, which is moved away from the brake shoe 52 by a return spring 55, and has a cylinder chamber 56 formed in the side wall 18 of the transmission case 4 corresponding to the shaft portion 52A of the brake shoe 52; A piston ram 54 is fitted into the cylinder chamber 56 in an oil-tight and slidable manner.

The protruding end surface of the piston ram 54 and the opposing end surface of the shaft portion 52A of the brake shoe 52 are in a non-contact state as shown in FIG.
When hydraulic pressure is applied against the spring 55, the brake shoe 52 slides to the left in FIG.
is pressed to prevent the interlocking gear 36 from rotating in conjunction with each other.

Pressure oil is supplied to and released from the piston ram 52 by attaching the relay steering case 19 to the side wall 18 of the transmission case 4 and assembling it inside the relay steering case 19 so as to cover the cylinder chamber 56 from the outside. Rotary valve 57
It is becoming more common to do so.

That is, the rotary valve 57 is
As shown in the figure, a horizontal hole 58 formed at the upper rear corner of the relay steering case 19;
It has oil passages 59 and 60 in the longitudinal and vertical directions formed perpendicularly to the inner end side of the hole 58, and a valve shaft 61 rotatably inserted into the hole 58. The oil passage 59 is communicated with the cylinder chamber 56 at the front end side, and the oil passage 60 is connected to the relay steering case 1.
It is connected to a hydraulic pump (not shown) via a joint 62 screwed onto the lower rear side of the pump 9.

The inner end of the valve shaft 61 has a notch 63 for communicating the oil passages 59 and 60, and a notch 65 for communicating the oil passage 59 with a through hole 64 formed in the side wall 18 of the transmission case 4. When the oil passages 59 and 60 are brought into communication, hydraulic pressure is supplied to the cylinder chamber 56, and when the oil passage 59 is brought into communication with the through hole 64, the oil in the cylinder chamber 56 is supplied to the transmission case 4. I'm starting to pull it out.

The valve shaft 61 is attached to the suspended steering case 19 and is prevented from coming off by a retaining plate 66, and a lever 67 that projects downward is fixed to the outer end of the valve shaft 61. A pin 68 is attached to the lower end of the lever 67.
A rod 69 is connected through the rod 69.
protrudes forward along the clutch rod 29, and is connected to a lever 70 provided midway on the clutch rod 29 at the front end side. When the clutch pedal 25 is depressed one step, the clutch 31 of the traveling system is disengaged, and the valve shaft 61 of the rotary valve 57 is rotated, so that the notch 63 connects the oil passages 59 and 60. There is.
Note that the relay steering case 19 is provided with a stopper 71 for the lever 67.

(Effects of the invention) According to the invention, since the valve 57 is incorporated into the steering case 19, the structure of the 18 side walls of the transmission case 4 can be simplified. Further, since the piston ram 54 for operating the brake 51 is housed in a cylinder chamber 56 formed in the side wall 18, and the cylinder chamber 56 is covered by the steering case 19, the structure is simple.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention,
Figure 1 is a cross-sectional plan view of the steering case part.
Figure 2 is a cross-sectional side view of the same, Figure 3 is the − of Figure 2.
Arrow view, Figure 4 is a side view of the rotary valve part,
FIG. 5 is a cross-sectional view of the same, FIG. 6 is a cross-sectional side view of the main parts of the tractor, FIG. 7 is a cross-sectional view of the power transmission section, and FIG. 8 is a view taken along the - arrow in FIG. 7. DESCRIPTION OF SYMBOLS 1... Tractor body, 4... Mission case, 18... Side wall, 19... Relay steering case, 41... Gear transmission mechanism, 47... Interlocking gear, 51... Brake, 52... Brake system,
54... Piston ram, 56... Cylinder chamber, 5
7...Rotary valve, 61...Valve shaft.

Claims (1)

[Scope of utility model registration request] A brake 51 is provided in the transmission case 4 to prevent inertial rotation of the power transmission system when the clutch 31 is disengaged, and a brake 51 is provided in the side wall 18 of the drive, which is provided with a steering case 19 outside the side wall 18 of the transmission case 4. A piston ram 54 for operating the brake 51 is provided in the cylinder chamber 56.
At the same time, a steering case 19 is attached to the side wall 18 so as to cover the cylinder chamber 56,
Preventing inertial rotation of the power transmission system in a tractor characterized in that the steering case 19 incorporates a valve 57 for supplying pressure oil to the cylinder chamber 56 when the clutch 31 is disengaged and for removing pressure oil when the clutch 31 is engaged. Device.