JPH019700Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is based on the inertia of the driven side of the main clutch when the main clutch is disengaged prior to the gear change operation of the mechanical transmission in agricultural tractors used for various agricultural tasks in the field. The present invention relates to an inertial rotation prevention device for preventing rotation.

In other words, this invention is an inertia rotation prevention device as described above, in which the braking action of the brake mechanism for inertia rotation prevention is not only achieved automatically by disengaging the main clutch, but also automatically by stopping inertia rotation. The present invention aims to provide a novel inertial rotation prevention device for agricultural tractors and the like, which can be released quickly and reliably to stop the inertial rotation.

Regarding the illustrated embodiment, the structure of the inertial rotation prevention device according to the invention will be explained. As shown in FIG. The transmission is transmitted to the rear of the fuselage within the clutch housing 2 and transmission case 3, which make up the clutch housing 2 and the transmission case 3, and transmitted to the left and right rear wheels 4 to rotate the rear wheels 4. The power is transmitted from inside through the transmission shaft 5 to the left and right front wheels 6 to rotate the front wheels 6 and cause the aircraft to travel, and is also transmitted to the PTO shaft 7 extending to the rear of the aircraft to drive it to the rear of the aircraft. This invention has been implemented in the following manner in an agricultural tractor configured to extract driving force from a connected working machine.

That is, a hollow drive shaft 8 shown in FIG. 2 is provided so as to straddle the clutch housing 2 and the inside of the transmission case 3, and this hollow drive shaft 8 is installed inside the front end of the clutch housing 2. It is driven by the engine 1 via a main clutch 10 which is disengaged by depressing a clutch pedal 9 shown in FIG. In addition, within the transmission case 3, a mechanical main transmission 12 is provided between the hollow drive shaft 8 and a transmission shaft 11 parallel to the lower part thereof. A mechanical sub-transmission device 14 is provided between the output shaft 13 and the output shaft 13, and the vehicle speed of the illustrated agricultural tractor is changed and controlled by these two transmission devices 12 and 14. The transmission output shaft 13 is connected to four directions of left and right rear wheels via a bevel gear 15 at the rear end, and a gear 16 on the output shaft 13, an intermediate gear 17, and a front wheel drive force extraction shaft 18. Idle gear 1
9. It is connected to the left and right front wheels 6 through the front wheel driving force extraction clutch 20 on the front wheel driving force extraction shaft 18, the front wheel driving force extraction shaft 18, and the transmission shaft 5. The transmission output shaft 13 is also connected to the above-mentioned
Connected to 7 directions of PTO shaft, ground PTO
A mechanical ground PTO clutch (not shown) is provided between the transmission shaft 22 and the PTO shaft 7.
Furthermore, a drive shaft 24 is also provided which is interlocked and connected to the engine 1 without going through the main clutch 10, and this drive shaft 24 is connected to a live PTO clutch and a live PTO transmission (not shown) to the PTO shaft 7. are connected via etc.

Since the transmission mechanism on the driven side of the main clutch 10 is configured as described above, the main transmission 12,
Sub-transmission device 14, front wheel drive force extraction clutch 20
Before operating the above-mentioned ground PTO clutch (not shown), first press the clutch pedal 9.
When the main clutch 10 is depressed, the main clutch 10 is disengaged. The inertial rotation prevention device according to this invention is a device for preventing inertial rotation on the driven side of the main clutch 10 when the main clutch 10 is disengaged as described above.
It is configured.

As similarly shown in FIG. 2, this inertial rotation prevention device includes a brake 27 having a brake drum 25 fixedly installed on the hollow drive shaft 8 and a brake shoe 26 installed opposite to the circumferential surface of the drum 25. of,
We are prepared. As shown in FIG. 3, the brake shoe 26 is supported at one end by a supporting wall portion 3a on the inner surface of the wall of the transmission case 3 so as to be rotatable around a pin 28, and is placed at a distance relative to the brake drum 25. It is said to be rotatable. A hydraulic cylinder 29 whose cylinder body is a part of the transmission case 3 is provided, and the other end of the brake shoe 26 is connected to a piston rod 29a of the hydraulic cylinder 29.
, a connecting rod 32 having connecting pins 30 and 31 at both ends.
They are interlocked and connected. Hydraulic cylinder 29
The piston 29b is a single-acting type that is moved to extend by hydraulic pressure applied to an oil chamber 29c behind the piston 29b, and contracted by the action of a spring 29d. When hydraulic pressure is supplied to the oil chamber 29c through the oil passage 33 and the hydraulic cylinder 29 is extended, the brake shoe 26 is brought into pressure contact with the brake drum 25, so that the braking action of the brake 27 can be obtained. , the brake 27 is configured. That is, the brake 27 is configured as a hydraulically operated brake.

In order to selectively supply hydraulic pressure to the hydraulic cylinder 29 of the hydraulic brake 27, a hydraulic circuit as shown in FIG. 4 is provided. This hydraulic circuit is configured to supply hydraulic pressure from an oil tank 36, which is also used in the transmission case 3, to a hydraulic cylinder 29 by a hydraulic pump 37. As shown in FIG. 2, it is installed on the hollow drive shaft 8 and is driven by the engine 1 via the main clutch 10. Also, the oil passage 33 is led from the hydraulic pump 37 to the hydraulic cylinder 29.
Hydraulic pressure supply circuit 3 whose tip end is configured with
The lubricating oil circuit 39 branched from the middle of 8 has a first line that keeps the lubricating oil circuit 39 in a conductive state as shown in the figure.
An electromagnetic switching valve 40 having a position I and a second position blocking the circuit 39 is inserted and installed, and the lubricating oil circuit 40 is connected to the main transmission 12 as shown in FIG. A plurality of free rotating speed change gears 41, 42, 43, 4 loosely installed on the transmission shaft 11
4 through the transmission shaft 11. The electromagnetic switching valve 40 is moved to the second position by the energization of the solenoid 40a, and the sensor switch 45, which energizes the solenoid 40a when turned on, is activated by the clutch pedal 9, as shown in FIG. A main clutch 10 is provided opposite to the pedal arm 9a.
When the clutch pedal 9 is depressed to disengage, the pedal arm 9a turns on the solenoid 40.
It is said that a is excited.

Similarly, as shown in FIG.
For example, the relief circuit 46 branched from 30
A relief valve 47 set to a relatively low oil pressure of Kg/cm ² is inserted and installed. A hydraulic accumulator 49 is connected to the relief circuit 46 via a throttle 48, and the hydraulic accumulator 49 itself is caused by the hydraulic action of an accumulator piston 49a being moved backward against the force of an accumulator spring 49b. It is said to have a conventional structure that accumulates hydraulic pressure.

In addition, as shown in FIG.
1, the above-mentioned idle speed change gears 41, 42, 43, 44
as shown in the figure, or indirectly through the R intermediate gear 55, and the transmission shaft 1
Two sliding clutch metal fittings 56, 57 for selectively coupling each of the idle speed change gears 41, 42, 43, 44 to the transmission shaft 11 are provided on the first sliding clutch metal fittings 56, 57. Main shift lever 58 shown in the figure
By sliding operation by
-44 can be selectively coupled to the transmission shaft 11 to obtain a gear ratio of three stages in the forward direction and one stage in the reverse direction.

Further, as similarly shown in FIG. 2, the sub-transmission device 14 is provided with a hollow transmission shaft 59 that is loosely fitted onto the rear half of the drive shaft 24, and this hollow transmission shaft 59 is connected to the transmission shaft 11. The gears 60 and 61 are connected in a variable-variable manner, and two speed change gears 6 are mounted on the hollow transmission shaft 59.
2, 63, and outside the hollow transmission shaft 59,
A creep speed change gear 65 is provided which is connected to the speed change gear 62 in a deceleration manner via a gear reduction mechanism 64.
Furthermore, two shift gears 6 are mounted on the transmission output shaft 13.
6 and 67, and a clutch 68 is interposed between the transmission shaft 11 and the transmission output shaft 13 at the displacement of the shift gear 67.
As described above, the sub-transmission device 14 operates to displace the shift gears 66 and 67 using the sub-shift lever 69 shown in FIG. By this, the gear ratio of the first gear is selectively obtained, the gear ratio of the second gear is selectively obtained by the engagement of the gears 63 and 67, and the gear ratio of the third gear is selectively obtained by the engagement of the clutch 68.

Next, the operation of the illustrated inertial rotation prevention device according to this invention will be explained. During normal driving with the main clutch 10 engaged, the electromagnetic switching valve 40 is in the first position, so oil discharged from the hydraulic pump 37 is passed from the hydraulic supply circuit 38 to the lubricating oil circuit 39 to the transmission shaft 11. It is sent to the upper bearing part L,
The bearing portion L is lubricated. Since the hydraulic oil from the hydraulic pump 37 is supplied as lubricating oil to the bearing part L in this way, the oil pressure established in the oil pressure supply circuit 38 gradually becomes lower than the oil pressure set in the relief valve 47. , hydraulic cylinder 2
9 assumes a contracted state due to the action of the spring 29d, and the brake 27 does not operate.

The above-mentioned main transmission 12, sub-transmission 14, front wheel drive force extraction clutch 20, or a ground (not shown)
When the clutch pedal 9 is depressed to disengage the main clutch 10 in order to operate the PTO clutch, the sensor switch 45 causes the main clutch 10 to disengage.
By detecting the off state, the electromagnetic switching valve 40 is moved to the second position, and the lubricating oil circuit 39 is blocked. Therefore, the hydraulic pressure P ₀ set in the relief valve 47 is established in the hydraulic pressure supply circuit 38 , and this hydraulic pressure P ₀ is applied to the hydraulic cylinder 29 , and the hydraulic cylinder 29 operates the brake 27 . The extension works like this. On the other hand, hydraulic pump 3
7 is provided on the driven side of the main clutch 10, the rotational speed of the pump 37 decreases when the main clutch 10 is disengaged, and oil leaks from the circuit. As shown in FIG. ₂ , after a certain time t1 has elapsed since the main clutch 10 is disengaged, the hydraulic pressure P applied to the hydraulic cylinder 29 begins to fall below the set hydraulic pressure _P0 . If the above-mentioned hydraulic accumulator 49 is not provided, as shown by the relationship line _C0 shown by the chain line in FIG.
The hydraulic pressure P continues to drop rapidly, but since the illustrated device is particularly provided with a hydraulic accumulator 49, hydraulic oil flows into the hydraulic accumulator 49 through the throttle 48 during time _t1 , and the accumulator The spring 49b is compressed to store hydraulic pressure, and when the hydraulic pressure P begins to decrease as described above and becomes lower than the force of the spring 49b, the accumulator piston 49a is moved forward by the force of the spring 49b, and the hydraulic pressure is supplied to the hydraulic pressure supply circuit 38. By replenishing the hydraulic oil, the drop in the oil pressure P is prevented for a certain period of time, and the oil pressure P is maintained at a relatively high value for a certain period of time, as shown by the relationship line _C1 shown in Fig. 5. becomes. In this way, the hydraulic accumulator 49 prevents a rapid drop in the hydraulic pressure P acting on the hydraulic cylinder 29 for a certain period of time, so that the brake 27 operated by the hydraulic cylinder 29 can quickly reduce the pressure of the hollow drive shaft 8. Stop inertial rotation. Then, since the oil pressure P decreases rapidly,
Since the hydraulic cylinder 29 quickly contracts under the action of the spring 29d and releases the brake 27, a state can be obtained in which a speed change or a clutch operation can be performed quickly. The above-mentioned throttle 48 causes the hydraulic accumulator 49 to open when the main clutch 10 is disengaged.
This prevents the rapid inflow of oil into the hydraulic cylinder 29 from substantially reducing the rate of oil flowing into the hydraulic cylinder 29 and delaying the initial operation of the hydraulic cylinder 29.

In the above embodiment, the hydraulically actuated clutch 27
A hydraulic pump 37 for supplying hydraulic pressure to,
Although the pump is also used as a lubricating oil supply pump, the present invention is not limited to such a configuration.

As is clear from the above description, the inertial rotation prevention device for agricultural tractors, etc. of this invention is provided with a hydraulic brake 27 for preventing inertial rotation on the driven side of the main clutch 10, and when the main clutch 10 is disengaged, Hydraulic pressure is supplied to the hydraulically operated brake 27 by a hydraulic pump 37 provided on the driven side of the main clutch 10 and a switching valve 40 whose position is switched to a hydraulic pressure supply position in conjunction with the switching operation of the main clutch 10. At the same time, a throttle 4 is installed in the hydraulic pressure supply circuit 38 for the hydraulically operated brake 27.
The brake 27 for preventing inertial rotation is automatically activated by the operation of the main clutch 10 when the switching valve 40 is displaced.
Since the drive of the hydraulic pump 37 is stopped by disengaging the main clutch 10, the operation of the brake 27 is automatically released when the inertial rotation is stopped.
Furthermore, the above-mentioned hydraulic accumulator 49 maintains the hydraulic pressure applied to the brake 27 at a high level for a certain period of time, thereby achieving the effect of quickly and reliably stopping the inertial rotation.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of an agricultural tractor equipped with an embodiment of this invention, Fig. 2 is a mechanical diagram showing the main parts of the transmission mechanism of the tractor, and Fig. 3 is a vertical sectional view of the main parts of the tractor. , FIG. 4 is a circuit diagram of the hydraulic circuit in the same embodiment, and FIG. 5 is a schematic graph showing the operation of the same embodiment. DESCRIPTION OF SYMBOLS 1...Engine, 3...Mission case, 8...Hollow drive shaft, 9...Clutch pedal, 10...Main clutch, 11...Transmission shaft, 13...Transmission part output shaft, 14...
Sub-transmission device, 20...Front wheel drive force extraction clutch,
25...brake drum, 26...brake shoe,
27... Brake, 28... Pin, 29... Hydraulic cylinder, 29a... Piston rod, 29b... Piston, 29d... Spring, 30, 31... Connection pin, 32... Link, 33... Oil passage, 37... Hydraulic pump, 38... Hydraulic supply circuit, 39...Lubricating oil circuit, 4
0...Solenoid switching valve, 45...Sensor switch, 46
... Relief circuit, 47... Relief valve, 48... Throttle, 49... Hydraulic accumulator.

Claims (1)

[Scope of utility model registration request] A hydraulically actuated brake is provided to prevent inertial rotation on the driven side of the main clutch, and when the main clutch is disengaged, a hydraulic pump provided on the driven side of the main clutch and the main clutch disengage operation are applied to the hydraulically actuated brake. A hydraulic accumulator is configured to supply hydraulic pressure by a switching valve whose position can be switched to a hydraulic pressure supply position, and is connected to the hydraulic pressure supply circuit for the hydraulically operated brake via a throttle, and is characterized by a hydraulic accumulator. Inertial rotation prevention device for agricultural tractors, etc.