JPS6342199Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology belongs to the technical field of automatically controlling the hydraulic pressure applied to a hydraulic clutch provided in the transmission of a self-propelled agricultural machine such as a combine harvester.

<Summary> Therefore, this invention connects hydraulic passages formed in the transmission case to hydraulic clutches connected to respective transmission gears of a transmission connected to the drive shaft of a self-propelled agricultural machine such as a combine harvester. This invention relates to a transmission hydraulic valve structure having a rotary valve which is selectively communicated with a hydraulic motor through a rotary valve. The self-propelled agricultural machine has two types of ports, large and small, and when the accumulator in the cylinder strokes back, the small port is exposed first, and then the large port is exposed in the accumulator and selectively connected to its decompression chamber. This is an invention related to the structure of a transmission hydraulic valve.

<Prior Art> As is well known, as shown in FIG. 1, for example, when a combine 1 as a self-propelled agricultural machine travels in a field 2, crawlers 4 and 4' on both sides that carry a machine body 3 are driven by drive wheels 5, It rotates by rotational force from output shafts 6, 6' connected to the shaft 5'.

Therefore, the power is transmitted to the output shafts 6, 6' by the second
As shown in the figure, the output from the engine 7 drives the input shaft 9 inside the transmission case 8, and the driven pulley 1
0, 11, is transmitted via the belt 12, and the rotational force is transmitted to the main transmission gear group 14 via the auxiliary transmission gear group 13, which is a transmission, and also rotates the hydraulic motor 15 connected to the input shaft 9. .

On the other hand, the main transmission gear group 14 includes first speed gears F ₁ , 3
A speed gear F ₃ , a second speed gear F ₂ (not shown), and a reverse gear R are provided, and recently developed friction type hydraulic clutches 16 and 17 are respectively attached thereto.

Therefore, the rotary valve 2 is rotated by rotating the valve lever 19 installed in the operator's seat 18 of the combine 1.
0 spool 20 so that hydraulic pressure from the hydraulic motor 15 is introduced through the passage 22 to the hydraulic clutch 16 of the first gear _F1 , for example.

Regarding a rotary valve that allows the hydraulic passage to be freely selected via a port, for example, JP-A-50
This is disclosed in the Patent Publication No. 15228.

After the hydraulic pressure is regulated by the relief valve 24 provided in the hydraulic valve 23, the pressure is initially reduced and flows into the accumulator 26 through the throttle 25, and the clutch plate (not shown) of the hydraulic clutch 16 is pressed against the clutch plate (not shown). Press to connect to speed gear F ₁ .

As a result, the main transmission gear group 14 is linked to the first speed gear _F1 , and transmits its deceleration torque to the gears 27, 27' mounted on the output shafts 6, 6', thereby causing the combine 1 to travel in a predetermined direction. .

Of course, it goes without saying that the hydraulic passage 22 is formed within the mission case 8.

<Problems to be solved by the invention> However, the internal pressure on the inlet side of the throttle 25 increases due to flow resistance, and therefore, for example, when it is installed in a passage, oil leaks from the joint, resulting in pressure loss. There was a problem with this occurring.

To deal with this problem, the sealing of the seams can be made more reliable, but this has the disadvantage that workability and quality control become complicated, and as a result, the product cost increases.

By the way, the accumulator 26 is installed to control the hydraulic pressure so that the hydraulic clutch is connected in a so-called half-clutch state in the initial state, and in order to reduce the decompression capacity of the accumulator 26, Aperture 2 at the entrance or exit
5 is essential.

However, while it is desirable to connect the hydraulic clutch at full pressure during driving, the throttle 25, which is an essential element, reduces the braking force to the hydraulic motor 15.
The disadvantage was that it increased the load on the system.

<Purpose of the invention> The purpose of this invention is to solve the problems of the transmission hydraulic valve structure of self-propelled agricultural machines based on the above-mentioned conventional technology as a technical problem, to prevent oil leakage, eliminate pressure loss, and improve workability. Moreover, it is an object of the present invention to provide an excellent transmission hydraulic valve structure for self-propelled agricultural machinery that is easy to manage and reduces the load on the hydraulic motor, thereby benefiting the field of power technology application in the agricultural industry.

<Means/effects for solving the problems> In line with the above-mentioned purpose, the structure of this invention, which is summarized in the claims of the above-mentioned utility model, solves the above-mentioned problems by providing a rotary valve and a valve of the rotary valve. When one of the hydraulic clutches connected to each transmission gear provided in the port and the transmission case, and the hydraulic motor and the accumulator are brought into communication, the hydraulic pressure from the hydraulic motor is initially reduced by the relief valve. The flow flows into the accumulator in the rotary valve, increases the internal pressure of the accumulator, and correspondingly retracts the piston of the accumulator to reduce the hydraulic pressure, while the initial stroke back of the piston of the accumulator moves the accumulator and the valve body. Among the ports drilled in the cylinder, a small port is exposed and connected to the pressure reduction chamber of the valve body, and the suppressed hydraulic pressure is sent from the small port to the hydraulic clutch, and the hydraulic clutch receives the suppressed hydraulic pressure. When the piston of the accumulator reaches the end of its stroke, the large port is exposed to the decompression chamber, and the entire hydraulic pressure from the hydraulic motor is sent to the hydraulic clutch. A technical measure is taken to completely engage the transmission gear and transmit the driving torque to the output shaft linked to the crawler.

<Embodiment> Next, one embodiment of this invention will be described below with reference to FIGS. 1 and 2 and the drawings from FIG. 3 onwards.

23' is a transmission hydraulic valve which forms the gist of this invention and is used in the drive system of the combine harvester 1 of the agricultural machine shown in Fig. 1, and is similar to the well-known relief valve 2.
4 connects the hydraulic chamber 24' at the tip thereof to a passage 28 formed within the wall thickness t of the transmission case body 8.
The case 8 is connected to the hydraulic motor 15 via the
A spool 29, which is fitted in the hydraulic chamber 24' and operates at a set pressure of, for example, 14 kg/cm ² , has its rear end pressed against a spring 30 as shown in FIG. The hydraulic chamber 24'
and the oil tank 31 are in communication with each other through a port 32 that is opened and closed by the spool 29.

On the other hand, 20' is a rotary valve, which is adjacent to the relief valve 24 via a horizontal plate 33.
The valve body 20'', which is provided in the mission case 8 and arranged in parallel with each transmission gear group 13, 14 in the same way as in the embodiment shown in FIG. A control lever 36 is fixed to the tip of the lever through a plate 37 that is in contact with the case 8.
Further, as shown in FIGS. 3 and 4, a groove 39 having a swivel joint function that can be freely connected to a passage 38 bored in communication with the hydraulic chamber 24' is formed in a U-shape in the valve body 20''. A port 40 provided around the circumference and bored in the groove 39 is connected to a reduced pressure chamber 47 within the valve body 20''.

Also, an oil drain port 48 facing the decompression chamber 47
A contoured portion 39' at the peripheral end of the groove 39 is in contact with the passage 38 and is connected to an oil drain passage 49 communicating with the oil tank 31 via a horizontal plate 33.

On the other hand, 50 is an accumulator, which operates at a set pressure of, for example, 12 kg/cm 2 provided in a cylinder 51 that is internally housed in the rotary valve 20' and integrally connected axially and concentrically to the valve body 20'^' . A piston 51' is pressed by a compression spring 52 and faces the decompression chamber 47 so as to be able to move forward and backward concentrically.

A small diameter portion 54 recessed in a circumferential groove 53 provided in the cylinder 51 has a throttle 54' serving as a small port, which is connected to the distal end 5 of the piston 51' when the piston 51' is in an inoperable state.
1'', the large port 54'' is faced to the rear of the piston 51' in the operating state, and the small port throttle 54' is connected to the large port at the initial stroke Δx of the piston 51'. 54'' is exposed to and communicates with the decompression chamber 47 at the stroke end Δx'.

Further, as shown in FIG. 5, a valve port 55 is formed on one side of the circumferential groove 53 in the axial direction, and a valve port 55 is formed on one side of the circumferential groove 53 in the axial direction.
F ₁ , 2nd speed F ₂ , 3rd speed F ₃ , 2nd gear installed in reverse R
Passages 56, 57, 58, which communicate with the hydraulic clutches 16, 17 shown in the figure via the horizontal plate 33,
59.

In addition, 60 is a ratchet ball, and the operating lever 3
Pressed by a compression spring 61 installed in 6,
It is adapted to be fitted into shift setting notches corresponding to passages 56 to 59 bored in the plate 37.

<Embodiment - Operation> In the above-described configuration, in order to run the combine harvester 1, the main switch (not shown) is turned on to start the engine 7, and the power is transferred to the drive pulley 1.
0, the sub-transmission gear group 13 from the input shaft 9 in the transmission case 8 via the belt 12 and the driven pulley 11.
At the same time, the hydraulic motor 15 connected to the input shaft 9 is rotated.

Then, the auxiliary transmission gear group 13 causes the main transmission gear group 14 of the constant meshing type to idle, and on the other hand, the hydraulic motor 15 transfers the oil in the oil tank 31 to the passage 28 formed in the thick part t of the transmission case 8. The hydraulic pressure is supplied to the hydraulic chamber 24' of the relief valve 24 through the hydraulic pressure chamber 24' of the relief valve 24.

The oil supplied to the hydraulic chamber 24' presses and retreats the spool 29 against the compression spring 30 with its hydraulic pressure, and the oil flows out from the port 32 exposed by the retreat of the spool 29. It is returned to tank 31.

Therefore, in order to drive the combine 1, the rotary valve 20' is rotated using the operating lever 36, and the valve port 55 and the passage 56 are communicated with each other.
That is, the passage 38 is brought into communication with the hydraulic chamber 24' and the groove 39 by the contoured portion 39' of the valve body 20'' of the rotary valve 20', and the spool 29 of the relief valve 24 causes the passage 38 to be in communication with each other. The pressure-adjusted oil is introduced into a decompression chamber 47 in the rotary valve 20' via a passage 38 and a groove 39.

Then, the oil in the decompression chamber 47 reaches the piston 5.
1' is moved backward against the elastic force of 12 kg/cm ² of the compression spring 52, and after flowing out at low pressure from the small port throttle 54' exposed at the initial state of the stroke Δx into the circumferential groove 53, the 1st speed Hydraulic pressure is gradually applied to the hydraulic clutch 16 connected to the gear F ₁ through the valve port 55 and the passage 56, so that the hydraulic clutch 16 transfers power to the drive shaft 6 in a so-called half-clutch state. 6'.

Then, when the piston 51' gradually retreats and reaches the stroke end Δx', the large port 54'' is exposed to the decompression chamber 47, and the oil flows through the large port 54''.
4'', and the hydraulic clutch 16 has a predetermined pressure 14
Connected in close contact at Kg/cm ² .

During this time, the pressure corresponding to the oil flow resistance due to the throttle 54' is applied only to the inside of the decompression chamber 47, so that no oil leaks from other joints.

Of course, each transmission gear F ₂ , F ₃ ,
Of course, even when the passages 57, 58, and 59 facing R are selectively communicated with each other by the operating lever 36, the same result as described above can be obtained.

It goes without saying that the embodiment of this invention is not limited to the above-mentioned embodiment. For example, the compression spring that presses the piston of the accumulator may be adjusted at the rear end to be compressed from the outside, and the port diameter may be adjusted. Various embodiments can be adopted, such as selectively providing three or more types.

<Effects of the invention> As mentioned above, according to this invention, the transmission hydraulic control system for self-propelled agricultural machinery such as combines,
The cylinder of the rotary valve, which selectively communicates with the hydraulic clutches connected to each transmission gear provided in the transmission case through corresponding hydraulic passages, and which houses an accumulator, has two types of large and small ports for the hydraulic passages. One large port opens at the end of the stroke of the piston of the accumulator in the cylinder and communicates with the decompression chamber, and the other small port opens at the beginning of the stroke and communicates with the decompression chamber. Basically, the oil led to the hydraulic clutch is initially supplied from the small port at low pressure with flow resistance, and then, at the end of the piston stroke, the oil is supplied to the hydraulic clutch at low pressure from the large port. Since it is supplied without flow resistance, when shifting during driving,
A smooth transition from half-clutch to engagement is automatically made, which not only has the effect of improving operability, but also has the excellent effect of reducing the load on the hydraulic motor during engagement.

In addition, since the load on the hydraulic motor can be reduced, oil leakage does not occur even if the seals on each joint surface have a simple structure, and pressure loss is prevented.As a result, assembly work efficiency is improved. This has the advantage that it is possible to improve the

On the other hand, the large and small ports are of an integrated structure drilled into the rotary valve, making it easy to manufacture and assemble, eliminating the need for extra piping, which not only improves work efficiency but also makes the entire device more compact. effect is produced.

Not only is it easy to manufacture and assemble, but the simple structure also reduces product costs.
This has the effect of simplifying maintenance and management.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of the combine harvester, Fig. 2 is a schematic diagram of the transmission, Fig. 3 and the following are explanatory diagrams of one embodiment of this invention, Fig. 3 is its schematic sectional view, and Fig. 4 is FIG. 5 is a partially cutaway perspective view of the main part, and FIG. 5 is a cross-sectional view taken from FIG. 3. 1...Self-propelled agricultural machine, 13,14...Mitsusion, F ₁ ,
F ₃ ...Speed gear, 16, 17...Hydraulic clutch, 8
...Mission case, 56-59...Hydraulic passage, 1
5...Hydraulic motor, 20'...Rotary valve, 2
3'...Hydraulic valve, 50...Accumulator, 2
0''...Valve body, 51...Cylinder, 54...Port, 47...Decompression chamber, 51'...Piston, 54'...Small port, 54''...Large port, 51''...Front part.

Claims (1)

[Scope of utility model registration request] A rotary valve connected to a hydraulic motor is selectively communicated with a hydraulic clutch connected to each transmission gear provided in a transmission of a self-propelled agricultural machine through corresponding hydraulic passages formed in a transmission case. In the transmission hydraulic valve structure, the cylinder of the accumulator is shared with the cylinder of the valve body of the rotary valve, so that the piston of the accumulator faces the pressure reduction chamber of the rotary valve, and the part of the cylinder on the valve body side has the above-mentioned hydraulic pressure. Two types of ports, large and small, are drilled for the passage, of which the small port faces the front of the inactive position of the piston of the accumulator in the cylinder and opens into the cylinder, while the large port faces the front of the piston of the accumulator in the cylinder and opens into the cylinder. A transmission valve structure for a self-propelled agricultural machine, characterized in that it faces the front part in a stroke end position and opens into the cylinder, and both large and small ports can be selectively connected to the decompression chamber.