JPS6220751Y2 - - Google Patents

Description

[Detailed description of the invention] This invention consists of a driving side transmission shaft and a driven side transmission shaft, which are arranged concentrically at a relatively high place in a housing that houses a transmission mechanism. A clutch housing is fixedly installed on the transmission shaft, and one and the other friction elements are supported by the driving side transmission shaft and the clutch housing in a slidable and non-rotatable manner, and a hydraulic pressure is formed in the clutch housing. A piston, which is displaced by selectively supplying hydraulic pressure to the chamber and presses the one and the other friction elements into frictional engagement, is placed in the clutch housing and is energized by a return spring to move in the opposite direction of the friction elements. A hydraulic clutch is provided for selectively connecting and disconnecting the two transmission shafts, and a brake band is wound around the outer circumferential surface of the clutch housing, and the brake band is connected to an operating device for the hydraulic clutch. a band for braking the driven-side transmission shaft when the hydraulic clutch is disengaged, the band being connected to the clutch housing so as to be displaced to a position where the clutch housing is tightened and non-rotatably braked when the hydraulic clutch is disengaged; The present invention relates to an inertial rotation prevention device equipped with the above-mentioned band brake in an agricultural tractor or the like in which the brake is constructed by using the clutch housing as a brake drum.

Providing a brake on the driven side of the clutch in a traveling work vehicle such as an agricultural tractor that quickly stops the inertial rotation of the rotary transmission member on the driven side of the clutch when the clutch is disengaged can be used, for example, when the clutch is disengaged. In cases where a transmission to be shifted by the clutch is provided on the driven side of the clutch and it is desired to quickly stop the rotation of the gears of the transmission prior to the shift operation, the clutch may be raised or lowered by a hydraulic lift device. The PTO shaft and This has been done when it is desired to quickly stop the drive of a working machine, and when the above-mentioned clutch is a hydraulic clutch as described above, the above-mentioned brake is applied to the hydraulic clutch when the hydraulic clutch is disengaged. It also prevents so-called drag, in which the friction element on the driven side rotates due to the drag phenomenon of lubricating oil accompanying the rotation of the friction element on the driving side, and the rotating transmission member on the driven side of the clutch rotates unexpectedly. Become.

When the brake associated with the clutch is configured as a band brake as described above when the clutch is a hydraulic clutch, the clutch housing of the hydraulic clutch is also used as a brake drum for the band brake. Therefore, the number of parts is reduced and the brake structure is simplified compared to the band brake, which has a separate brake drum structure. It is supposed to lubricate and cool the brakes.
A novel inertial rotation prevention device is provided.

In other words, as mentioned at the beginning, the band brake is installed at a relatively high location together with the hydraulic clutch in the housing that houses the transmission mechanism, and lubricating oil for lubricating the transmission member is located in the lower part of the housing as described above. However, since it is not immersed in such lubricating oil, or even if it is immersed, it is only partially immersed, so the brake operation is difficult compared to a band brake that performs braking action in lubricating oil. The brake band is less likely to slip due to the oil inside, and the brakes are highly effective and provide a large braking force.
However, on the other hand, conventionally, there was no mechanism for lubricating and cooling such brakes, so when the hydraulic clutch is engaged and the band brake is disengaged, the brake band of the band brake slides into contact with the clutch housing of the hydraulic clutch. There was a problem that caused significant wear and heat generation.

Therefore, this invention is a new invention that solves the above problems by using a structure that uses the clutch housing as a brake drum, while avoiding poor brake effectiveness as much as possible in agricultural tractors etc. with the structure described at the beginning. Inertial rotation prevention device,
This is what we are trying to provide.

Regarding the illustrated embodiment, to explain the structure of the inertial rotation prevention device for an agricultural tractor or the like according to this invention, as shown in FIG. The power is transmitted inward to the clutch housing 2, transmission case 3, and rear housing 4 that make up the fuselage housing, drives the left and right rear wheels 5 to cause the fuselage 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, as shown in FIG. 2, in the rear end of the rear housing 4, a shaft is disposed between the PTO shaft 6 and the transmission shaft 7 in the preceding stage to change and control the rotation speed of the PTO shaft 6. A PTO transmission 8 is provided, and a transmission shaft 9 is disposed concentrically with the transmission shaft 7 and is constantly rotationally driven by the engine 1 at the front stage of the transmission shaft 7. Then, between the transmission shaft 9 located on the driving side and the transmission shaft 7 located on the driven side, the transmission shafts 9 and 7 are selectively connected and disconnected, and the transmission to the PTO shaft 6 is performed. A hydraulic clutch 10 for selectively turning on and off power is provided with a clutch housing 11 of the hydraulic clutch 10 fixed to a driven side transmission shaft 7. This hydraulic clutch 10 includes the clutch housing 11 described above.
Clutch 1 is constructed by alternately disposing friction plates 13 for a plurality of plates and mating plates 14 on rotation support metal fitting 12 fixed to driving side transmission shaft 9 by spline fitting.
It is configured to be a well-known multi-plate hydraulic clutch, which is supported so that it can only slide freely along the 0-axis direction and obtains frictional engagement between the friction plate 13 and the mating plate 14 by hydraulic action to obtain clutch engagement. has been done. A piston 16 is provided within the clutch housing 11 and is urged to move backward by a return spring 15. By supplying pressure oil to a hydraulic chamber 17 behind the piston 16, the piston 16 can be moved forward. ,
Pressure contact between the friction plate 13 and the mating plate 14 is obtained.

The inertial rotation prevention device according to this invention is as described above.
Prior to shifting the PTO transmission 8, when the hydraulic clutch 10 is disengaged to make the shifting operation smooth, or when the hydraulic clutch 10 is disengaged, the hydraulic pressure installed at the rear end of the upper surface of the aircraft as shown in FIG. Prior to raising the working machine to the standby position by the lift device 18, when the hydraulic clutch 10 is disengaged in order to stop the drive of the working machine that receives transmission from the PTO shaft 6 and to ensure safety, the transmission shaft 7 and
In order to prevent inertial rotation of the PTO shaft 6 and quickly stop the rotation of the shafts 7 and 6, the following arrangement is provided.

That is, as shown in FIGS. 2 and 3, the inertial rotation prevention device is a band constructed by using the clutch housing 11 of the hydraulic clutch 10 as a brake drum and wrapping a brake band 19 around the outer peripheral surface of the clutch housing 11. A brake 20 is provided. As shown in FIG. 3, one end of the brake band 19 is fixed to a pin 21, and the other end of the brake band 19 is attached to a bell crank 23 that is rotatably supported around a fulcrum pin 22. It is connected to the end of the arm with a pin 24. In order to selectively tighten the brake band 19 against the outer peripheral surface of the clutch housing 10 and selectively operate the band brake 20,
Similarly, a single-acting hydraulic cylinder 25 shown in FIG.
However, it is provided. This hydraulic cylinder 25 is
It is connected to the bell crank 23 by inserting an operating pin 26 fixed onto the piston rod 25a into a long hole 27 at the end of the other arm of the bell crank 23. When the piston rod 25a is extended by the action of the compression spring 25b built into the hydraulic cylinder 25, the bell crank 23 is rotated in the direction of arrow C around the fulcrum pin 22, and the brake band 19 is moved against the clutch housing 1.
0 to the outer circumferential surface, the band brake 20 is operated for braking, and conversely, when pressure oil is supplied to the hydraulic chamber 25d in front of the piston 25c and the piston rod 25a is caused to contract, the bell crank 23 is moved around the fulcrum pin 22. Rotate in the opposite direction of arrow C,
It is configured to release the braking action of the band brake 20 by releasing the tightening of the brake band 19 against the outer peripheral surface of the clutch housing 10.

The hydraulic clutch 10 is connected to the band brake 20.
In order to automatically perform a braking operation when the hydraulic clutch 10 is disengaged, as shown in FIG. An oil supply/discharge circuit 29 is connected to the hydraulic chamber 25d of the hydraulic cylinder 25 by a connection circuit 30. The above-mentioned switching valve 28 has an oil supply circuit 34 that guides hydraulic oil at a hydraulic pressure set by a pressure regulating valve 33 from an oil tank 31 by a hydraulic pump 32, and an oil drain circuit 35 that returns the hydraulic oil to the oil tank 31. The two ports on the primary side are connected to the hydraulic clutch 10 via an oil supply circuit 34 and an oil supply/discharge circuit 29.
and the working position of supplying pressure oil to the hydraulic clutch 1.
0 to the oil tank 31 via the oil supply and discharge circuit 29 and the oil discharge circuit 35. Therefore, when the switching valve 28 is in the operating position and the hydraulic clutch 10 is engaged, pressure oil is supplied to the hydraulic cylinder 25 and the band brake 20 does not perform the braking operation;
When moving the hydraulic clutch 10 from the operating position to the neutral position and disengaging the hydraulic clutch 10, the hydraulic cylinder 25
is the oil drain from the hydraulic chamber 25d and the spring 25
The band brake 20 performs a braking operation by being extended by force b.

In particular, the clutch housing 11 includes:
As clearly shown in FIG. 4, a small diameter oil hole 36 is bored through which the hydraulic chamber 17 communicates with the inner surface of the brake band 19 when the piston 17 is in the forward position. The oil hole 36 has a small diameter so that oil leakage toward the inner surface of the brake band 19 through the oil hole 36 will not substantially cause a decrease in the oil pressure in the hydraulic chamber 17. As in a modification shown in FIG. 5, a relief valve 37 having an appropriate relief pressure may be inserted into an oil hole 36' corresponding to the oil hole 36.

The above-mentioned PTO transmission 8 includes two speed change gears 38, which are provided on the transmission shaft 7 and are integral with the shaft 7.
39 and the above-mentioned speed change gear 3 which is loosely fitted to the PTO shaft 6.
Two free rotating gears 40 and 41 are meshed with gears 8 and 39, respectively, and have pawls 40a and 41 on their boss portions.
two free rotating gears 40, 41 forming a;
A shift metal fitting 42 is slidably provided on the PTO shaft 6 by spline fitting between the two free rotating gears 40 and 41, and has pawls 42a and 42b that can be engaged with the pawls 40a and 41a, respectively. The shift hardware 42 is configured to include a shift hardware 42. This PTO transmission 8 selectively slides and displaces the shift hardware 42 on the PTO shaft 6, and the pawls 40a,
By connecting the free rotating gear 40 to the PTO shaft 6 through the meshing between the teeth 42a, the gear ratio of 1st speed can be set.
By coupling to the PTO shaft 6, it is possible to selectively obtain two speed change ratios. In FIG. 2, reference numerals 43 and 44 respectively designate housing lids 4a at the rear end of the rear housing 4 to guide hydraulic oil from the hydraulic pump 32 to the hydraulic chamber 17 of the hydraulic clutch 10 via the switching valve 28.
and the transmission shaft 7, and 45 and 46 are oil passages bored through the transmission shaft 7, respectively, and the transmission shaft 7 Hollow bearing part 9a at the rear end of the transmission shaft 9 supporting the front end part and the hydraulic clutch 1
This is an oil passage bored through the transmission shaft 9 and the transmission shaft 7 to lead to the friction plate 13 and the mating plate 14 inside the transmission shaft 9.

Since the illustrated inertial rotation prevention device according to this invention is configured as described above, the switching valve 28 is moved from the operating position prior to the gear change operation of the PTO transmission 8 or the upward movement of the working machine by the hydraulic lift device 18. When moving to the neutral position, disengaging the hydraulic clutch 10 and releasing the connection between the transmission shafts 9 and 7,
Oil is drained from the hydraulic chamber 25d of the hydraulic cylinder 25, and the hydraulic cylinder 25 is connected to the compression spring 25b.
As a result, the transmission shaft 7 is extended by the band brake 20, and the transmission shaft 7 is braked by the band brake 20.
Braking of the PTO shaft 6 is also obtained. Therefore, inertial rotation of the transmission shaft 7 and the PTO shaft 6 is prevented, and rotation of the shafts 7 and 6 can be quickly stopped. The braking force of the band brake 20 determined by the force of the compression spring 25b of the Nako hydraulic cylinder 25 is set to a relatively small force, and the braking force of the band brake 20 is set to a relatively small force. , 39 are allowed to rotate. The small diameter oil hole 36 or 36' bored in the clutch housing 11 of the hydraulic clutch 10 is connected to the fourth,
As shown in Fig. 5, when the hydraulic clutch 10 is disengaged and the piston 16 is retracted, it is blocked by the piston 16, and when the hydraulic pressure is supplied to the hydraulic chamber 17, the piston 16 moves forward, and the hydraulic clutch 10 is engaged, the piston 16 is blocked. 16 is released and the hydraulic chamber 17 is communicated with the inner surface of the brake band 19, the engagement state of the hydraulic clutch 10 when the band brake 20 is in the non-operating state, that is, the brake When the band 19 is loosened and the band 19 comes into sliding contact with the outer peripheral surface of the rotating clutch housing 11, the high pressure oil supplied to the hydraulic chamber 17 flows through the oil hole 3.
6 or 36' to the inner surface of the brake band 19, and the oil lubricates and cools the brake band 19 and the surface of the clutch housing 11 with which it makes sliding contact.
wear and heat generation are suppressed. Conversely, when the hydraulic pressure is removed from the hydraulic chamber 17, the hydraulic clutch 10 is disengaged, and the band brake 20 is operated, the oil hole 26 or 26' is blocked by the piston 16, and the supply of oil to the inner surface of the brake band 19 is prevented. Clutch housing 1
The tendency of the brake band 19, which is pressed against and frictionally engaged with the outer circumferential surface of the brake band 1, to slip due to oil is reduced, and the braking action by the band brake 20 can be reliably achieved.

In the illustrated embodiment, the friction element supported by the clutch housing 11 is opened on the inner and outer circumferential surfaces of the clutch housing 11.
The claws on the outer peripheral end of the friction element are fitted into the slit-shaped slots formed in the clutch housing 1.
The brake band 19 is supported slidably and non-rotatably on the brake band 19 at a position avoiding the slot.
However, when a slot corresponding to the above-mentioned slot is formed in the shape of a notch in the inner peripheral surface of the clutch housing 11 without opening in the outer peripheral surface of the housing 11, the brake band 19 is When viewed in the axial direction of the clutch housing 11, it may be wrapped around the outer peripheral surface of the housing 11, extending over the friction elements 13, 14 installation portion. Furthermore, connecting the brake band 19 to the operating device of the hydraulic clutch 10 in such a way that the brake band 19 is displaced to a position in which the clutch housing 11 is tightened when the hydraulic clutch 10 is disengaged is a switching mechanism for the hydraulic clutch 10. This can also be achieved by connecting the brake band 19 to the operating lever of the valve 28 by means of a mechanical connection.

As is clear from the above description, the inertial rotation prevention device of this invention consists of a driving side transmission shaft 9 and a driven side transmission shaft 9, which are arranged concentrically at a relatively high place in the housing 4 that houses the transmission mechanism. A clutch housing 11 is fixedly installed on the driven side transmission shaft 7 of the transmission shaft 7, and one and the other friction elements 1 are attached to the driving side transmission shaft 9 and the clutch housing 11.
3 and 14 respectively slidably and non-rotatably, and the clutch housing 11
A piston 16 is disposed within the clutch housing 11 and is displaced by selectively supplying hydraulic pressure to a hydraulic chamber 17 formed within the clutch housing 11 to press the one and the other friction elements 13 and 14 into frictional engagement. Friction elements 13, 14
A hydraulic clutch 10 is provided to move and energize in opposite directions to selectively connect and disconnect between the two transmission shafts 9 and 7, and a brake band 19 is wound around the outer peripheral surface of the clutch housing. The brake band 19 is connected to the operating device for the hydraulic clutch 10 in such a manner that when the hydraulic clutch 10 is disengaged, the clutch housing 11 is moved to a position where the clutch housing 11 is tightened and non-rotatably braked. A band brake 20 for braking the driven side transmission shaft 7 when the clutch 10 is disengaged is attached to the clutch housing 1.
1 as a brake drum, small diameter oil holes 36, 36' that communicate the hydraulic chamber 17 with the inner peripheral surface of the brake band 19 are installed in the clutch housing 11.
When the hydraulic clutch 10 is disengaged, the oil hole is blocked by the piston 16, and when the hydraulic clutch 10 is engaged, the piston 16 is displaced in the direction of the friction elements 13 and 14, the oil hole is blocked. The feature is that the holes are arranged and drilled in such a way that they are released, and the following effects are achieved.

That is, in the inertial rotation prevention device of this invention, the band brake 20 for preventing inertial rotation of the rotary transmission member on the driven side of the hydraulic clutch 10 when the hydraulic clutch 10 is disengaged is configured such that the clutch housing 11 of the hydraulic clutch 10 is configured as a brake drum. Utilizing the installed structure, a small diameter oil hole 36 or 36' that communicates the internal hydraulic chamber 17 with the inner surface of the brake band 19 on the outer circumferential surface of the clutch housing 11 is inserted into the piston for actuating the clutch 10. 16
When the clutch 10 is engaged, the lock is blocked and when the clutch 10 is disengaged, the block is released depending on the position of the brake band 19. Oil for clutch operation is supplied to the inner surface of the brake band 19 only when the hydraulic clutch 10 is in the engaged state and the brake band 19 is relaxed and in sliding contact with the clutch housing 11. Therefore, when the brake 20 is in operation, the brake band 19 is hard to slip due to oil and the brake 20 is effective, but when the band brake 20 is not in operation, the inner surface of the brake band 19 can cause wear and heat generation of the brake band 19. By supplying oil to the brake pad, the band 19 is lubricated and cooled, thereby suppressing the above-mentioned wear and heat generation and extending the life of the brake.

[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 longitudinal sectional side view of the main parts of the tractor, and Fig. 3 is a longitudinal sectional front view of the embodiment and the hydraulic pressure in the embodiment. A circuit diagram of the circuit, FIG. 4 is a longitudinal sectional side view showing an enlarged part of FIG. 2, and FIG. 5 is a longitudinal sectional side view similar to FIG. 4 showing a modification. 6... PTO shaft, 7... Transmission shaft, 9... Transmission shaft, 10... Hydraulic clutch, 11... Clutch housing, 12... Rotating hardware, 13... Friction plate,
14... Opponent board, 15... Return spring, 16...
... Piston, 17 ... Hydraulic chamber, 19 ... Brake band, 20 ... Band brake, 21 ... Pin, 22 ... Fulcrum pin, 23 ... Bell crank,
24...Pin, 25...Hydraulic cylinder, 25a...
...Piston rod, 25b...Compression spring, 25
d...Hydraulic chamber, 26...Operating pin, 27...Elongated hole, 28...Switching valve, 29...Oil supply and drain circuit, 30
...Connection circuit, 36, 36'...Oil hole.

Claims (1)

[Scope of utility model registration request] Of the driving side transmission shaft 9 and the driven side transmission shaft 7 that are arranged concentrically at a relatively high place in the housing 4 that houses the transmission mechanism, a clutch housing 11 is mounted on the driven side transmission shaft 7. is fixedly installed, and one and the other friction elements 13 and 14 are supported by the power transmission shaft 9 and the clutch housing 11 in a slidable and non-rotatable manner, respectively, and a hydraulic pressure formed in the clutch housing 11 is fixedly installed. said one and the other friction element 13 being displaced by the selective supply of hydraulic pressure to the chamber 17;
A piston 16 that presses and frictionally engages the piston 14 is placed in the clutch housing 11, and a return spring 15 is inserted into the clutch housing 11.
A hydraulic clutch 1 for selectively connecting and disconnecting the two transmission shafts 9 and 7 by energizing the friction elements 13 and 14 in opposite directions.
0, and a brake band 19 is wrapped around the outer circumferential surface of the clutch housing 11, and when the hydraulic clutch 10 is disengaged from the operating device of the hydraulic clutch 10, the brake band 19 is tightened to tighten the clutch housing 11. A band brake 20 is connected so as to be displaced to a non-rotatably braking position to brake the driven side transmission shaft 7 when the hydraulic clutch 10 is disengaged, and the clutch housing 11 is used as a brake drum. A small diameter oil hole 36 that communicates the hydraulic chamber 17 with the inner circumferential surface of the brake band 19 in an agricultural tractor or the like installed in the structure;
36' to the clutch housing 11, and when the hydraulic clutch 10 is disengaged, the oil hole is blocked by the piston 16 and the piston 16 is displaced in the direction of the friction elements 13 and 14. An inertial rotation prevention device characterized by being arranged and drilled so that the block of the oil hole is released in the state.