JPS619209A - Hydraulic control mechanism of rice planter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides pressure oil supply, oil drain, and oil supply/drain cutoff to a single-acting hydraulic cylinder controlled by a spool-type three-position switching control valve. In addition to raising, lowering, and fixing the seedling planting device, the spool of this control valve is switched to operate based on the vertical movement detection of the sensor float provided in the seedling planting device, and the seedling planting device is maintained at a constant level above the ground. The present invention relates to a hydraulic control mechanism for a rice transplanter configured as described above.

[Conventional technology]

The spool of the control valve is formed with a parallel step-like underlap portion that acts in a certain small range between the neutral position and the raised position of the seedling planting device, and in the working range of this underlap portion, the pump port oil The chamber and the cylinder port boat oil chamber communicate with each other through a small gap on the outer periphery of the underlap part, and the pump port oil chamber also communicates with the drain oil chamber through a small gap, thereby reducing the pressure of oil supply and drainage. There are some devices designed to bring about a neutral stable state due to equilibrium (for example, JP-A-56-144004).

[Problem that the invention seeks to solve]

In the conventional means, the raising and lowering operation of the seedling planting device is brought about by a slight displacement of the spool from the neutral stable state due to hydraulic equilibrium, so the response is quick and smooth compared to a general three-position switching control valve, Stable lift control with little overshoot can be performed, and if the spool is manually operated to the rising side when changing the direction of the aircraft at the edge of a ridge, the entire amount can be supplied without going through the underlap. However, because the operating range of the underlap portion is small, the sensor float during planting runs in fields where the plowing surface is relatively uneven. The vertical displacement of the spool becomes thicker and the spool becomes 0. ．． . Ex
s &i; 3□9. , □4.1ヮ7.6)
This was done rapidly due to the large amount of supply, and overshoot tended to occur.

The present invention aims to further stabilize the control while maintaining the operability at the edge of the ridge as before by improving the control valve and its manual operation structure.

[Failure to solve the problem]

In order to achieve the above object, in the present invention, a parallel step-like underlap portion is formed on the spool of the control valve, and the underlap portion acts in the middle between the neutral position and the raised position of the seedling planting device. In the neutral position side action range, the pump port oil chamber and the cylinder port oil chamber communicate through a small gap formed around the underlap part, and the pump port oil chamber and drain port oil chamber communicate with each other through a small gap. The pump port oil chamber and the cylinder port oil chamber communicate with each other through a small gap formed around the underlap portion in the working range on the upward side of the sprouted neck of the underlap portion. At the same time, the pump port oil chamber and the drain port oil chamber are shut off, and near the stroke end of the spool toward the upward side of the seedling planting device, the pump port oil chamber is short-circuited to the cylinder port oil chamber without going through the underlap part. When the length of the underlap portion is set so that the spool is manually operated, and the lever that manually operates the spool is in the automatic control position, the spool moves near the upward stroke end and the pump port oil chamber is filled with cylinder port oil. A restraining member is provided to prevent short communication with the chamber and to allow movement of the spool to the upward stroke end when the lever is in the forced upward position.

[For production]

According to the above configuration, even if the spool is slightly displaced from the neutral stable state of hydraulic equilibrium via the underlap part to the upward side, the pressure oil in the pump port oil chamber is transferred to the cylinder port oil chamber through a small gap on the outer periphery of the underlap part. Inflow and slow rise control is performed. In normal planting when the manual control lever is in the automatic control position, the movement of the spool to the vicinity of the upward stroke end is sometimes prevented, and the appearance of rapid upward movement is checked, and the lever is forced to operate. Only when a rising operation is performed, the spool can be moved to the rising stroke end, and a rapid rising operation is performed by supplying the entire amount without going through the underlap.

〔Effect of the invention〕

Therefore, when changing the direction of the machine at the edge of a ridge, the seedling planting device can be raised rapidly as before, and the machine can turn quickly without causing the seedling planting device to drag on the rice field. During controlled planting, there is no rapid rise control during operation, and stable lift control without overshoot makes it possible to maintain the level of the seedling planting device.

〔Example〕

Figure 6 shows a riding type rice transplanter equipped with the control structure of the present invention.
A seedling planting device (3) is connected and protected so as to be able to rise and fall freely through a link V & structure (2) connected to the rear of the traveling vehicle body (fl), and this link Ia: structure (2) is supplied with pressurized oil. A single-acting hydraulic cylinder (+41) that extends and shortens when oil is discharged moves upward and downward, and a spool-type three-position switching control valve (6) that controls the operation of the hydraulic cylinder (4) is used to plant seedlings. The sensor float (
6) The control valve (5) is switched based on the ground pressure fluctuations exerted by K to raise and lower the seedling planting device (3), thereby maintaining the ground pressure of the sensor float (6) constant and raising and lowering the seedling planting device. (3)
The structure is configured to perform control to stabilize the ground level.

FIG. 7 shows the specific structure of the control mechanism,
The front part of the sensor float (6), which can swing up and down about the rear fulcrum (3), and the fixed member (7) of the seedling planting device (3) are connected by bending links +81 and +81, and the bending links ( e), release wire (9) according to the bending and stretching of +8)
and control valve (5) with its inner wire (9a).
It is configured to switch and operate. In other words, the ground pressure of the sensor float (6) and the refraction link +s+, (
When the elastic force of the spring 00) K that urges the 8) to extend is balanced, the control valve (5) is in a neutral state, the hydraulic cylinder (4) is stopped, and the seedling planting device (3) is level with the ground. is maintained constant, and when the vehicle body ftl enters a deep part of the plowing platform and the ground level of the seedling planting device (3) decreases,
The ground pressure of the sensor f0-) fi+ increases and the bending link is), (s) is bent against the spring (1o) K, and the inner wire (9a) is loosened, so that the control valve (5) Pressure oil supply status iK by αυ! The seedling planting device (3) is raised by the hydraulic cylinder (4), and when the sensor float ground pressure decreases to the set value, it returns to the neutral state described in 1. In addition, when the plowing platform becomes shallower, the subsidence of the vehicle body +1) decreases, and the ground level of the seedling planting device (3) increases, the ground pressure of the sensor float (6) decreases, causing the bending links i81, (8) to It is expanded by the elastic force of the spring (In) and the weight of the float, and as the inner wire (9a) is pulled, the control valve (5) is suddenly switched to the cylinder oil drain state, and the bacterial inoculation device (3) is connected to the sensor float grounding. It descends under its own weight until the pressure increases to the set value and stabilizes in a neutral state. By continuously performing the above control, the level of the seedling planting device (3) relative to the ground is maintained at a substantially constant level regardless of the amount of subsidence of the vehicle body (1).

Figures 2 to 5 show the detailed structure of the control valve (5), and show that the first song of the spool (2) inserted into the control casing (5a) rushes into the operation casing (5b). The pin 03 attached to the protruding end of the tin plate is connected to the operating casing (5b) K [the fork shaft (t) which is locked by the supported operating fork Q4 and linked to the release wire (9). By rotating the spool (2) in the forward and reverse directions, the spool (2) is switched to the neutral position ■, the pressure oil supply position (forced upward position) (goods), and the oil drain position (self-weight downward position) (D). .

Next, the function of the control valve (5) itself will be explained in detail.

As shown in Fig. 2, when the spool 0 is in the neutral position (NIK), the first oil chamber (bl is the oil chamber communicating with the pump port (P) (al and Dorenbo) and the spool (T) is connected to the pump port (P). 2) through the small diameter part (12m) and the pressure oil directly flows out, and the oil chamber (0) which communicates with the cylinder port (C) is blocked by the large diameter part (12b) and the hydraulic cylinder ( 4) is locked. Spool (2) is locked.
) is pushed in and switched to the pressure oil supply position (9), the first drain oil chamber fl)l is blocked by the large diameter portion (12c+), and the pump port oil chamber groove) and cylinder port oil chamber io1 are closed. They are communicated via the small diameter portion (12a), and pressure oil is sent to the cylinder port (C). Also spool (2)
is pulled out and switched to the oil drain position (9), the cylinder oil chamber 1o1 and the second drain oil chamber ial are moved to the second small diameter @
(12d), which makes it possible to drain oil from the hydraulic cylinder (4) and also allows for oil to be drained from the 1 pump port oil chamber (a).
) and the first drain oil chamber (BL are suddenly maintained in a state of communication and are short-circuited and drained. In addition, (7) in the figure is the pump bow)
a main relief valve communicating with fPl, (171 is a downward locking valve that prevents oil from draining from the cylinder (4) and prevents the oil leaf from unexpectedly lowering the seedling planting device (3);
It is normally open and shut off when driving on the road. Also, (to)
is a throttle valve installed in the cylinder exhaust 9 oil passage.
Used to adjust the rate of descent of the seedling planting device (3) under its own weight.

The configuration described above is not particularly different from the conventional one, and the present invention further includes the following configuration.

That is, an underlap portion is formed at the end of the large diameter portion (Bb) of the spool (2) on the pump port oil chamber 1al side. , over this underlap 5-),
The parallel stepped portion is configured to have a slightly smaller diameter (about 0. j at in radius difference) than the outer diameter of the large diameter portion (12b).

According to the above configuration, the underlap portion (2) is shown in FIG.
b) When the end K of the cylinder port oil chamber (o) is covered as shown in K, this oil chamber (0) becomes the underlap part (A).
is connected to the pump port oil chamber (al) through a minute gap (approx. 0.1-gap) (e), and the pump port oil chamber +al itself is connected to the first drain port oil chamber (bl with a small gap ( If it is communicated with f), it becomes k・7 > /
When the amount of overlap between the -5' section and the oil chamber (°) is less than 1, the small gap (f) becomes relatively large, the drain resistance becomes small, and a small amount of water flows from the hydraulic cylinder (4). This makes it possible to drain oil and bring about a slow descent state of the seedling planting device (8).
) increases, the small gap (f) becomes smaller and the drain resistance increases, and the back pressure due to the drain resistance and the hydraulic cylinder internal pressure become in equilibrium, and the hydraulic cylinder (4 ) is brought to a halt. Therefore, between the original neutral position (■) of the spool (2) and the pressure oil supply position (U), a slow descent position (DJ) is formed by draining oil through the underlap part (A), and A neutral stable position due to oil supply/discharge equilibrium is formed between the rapid descent position and the original pressure oil supply position.

Also, when the spool (2) was displaced a little more upward from this neutral stable position, the first drain oil chamber +bl was blocked by the large diameter part (12a), as shown in Figure 5 (b). The pump port oil chamber (a) and cylinder port oil chamber (0
) are communicated via a small gap +8) on the outer periphery of the underlap $IAI, and pressure oil is sent out little by little to the cylinder port (C) to perform a slow rising operation.

Then, when the spool (2) is further displaced to the upward side,
As shown in Figure 5 f, the end of the underlap part (A) enters the cylinder port oil chamber folK, and the pump port oil chamber +a+ and cylinder port oil chamber (0) are short-circuited by a large flow path. A rapid rise actuation is provided.

The control valve (5) having the above structure can also be switched manually, and its structure will be explained below.

A cylindrical shaft H is externally fitted onto the fork shaft θ frame, and a contact arm (E) fixed to the inner end of the case is configured to be able to abut the pin (2) only from one side, and the cylindrical shaft A manual operation lever (manufactured by Co., Ltd.) is attached to the outer end of αO.
When this lever (A) is switched to the forward limit position 0) as shown in Fig. 7, the contact arm (A) is moved to the third position.
As shown in the figure, the position is far away from the pin (to), and the spool is operated in forward and reverse directions using the fork α◆. φ, automatic elevation control is allowed.

In addition, the proximal end (21a) of the lever 1 is fixed inside the lever #1 member that comes into contact with the wire connecting arm (2) attached to the outer end of the fork shaft (2). When the spool Q is in the automatic control position (a), the underlapping portion of the spool Q is positioned as shown in FIG.

Also, when the lever (2) is operated to the rear limit position (c) in Fig. 7, the check member is retracted from the arm, and the contact arm handles the spool (a) to supply pressure oil at the end of the stroke. It can be forcibly shifted to position (9), thereby allowing the seedling planting device (3) to be forcibly and quickly raised to any desired height.

After raising the lever to the desired position, when the lever is returned to the position shown in Fig. 7 (b), the contact arm holder moves the spool (6) through the pin (2) to the neutral position.
(In this position (b), the contact arm (a) is held in position by a spring ball (incorporated), and the seedling planting device (3) is fixed at a predetermined raised position. .

In addition, the cylindrical shaft α is linked via a link to the operating lever ■ of the planting clutch (to) that connects and disconnects the power to the seedling planting device (3), and the manual operating lever is automatically When in the control position (a), only the planting clutch (to) of K can be engaged.

[Application example]

The present invention can be applied to a walk-behind rice transplanter that stably maintains the level of a seedling planting device that is directly connected to the companion body by controlling the elevation of the propulsion wheels that are in contact with the tiller.

[Brief explanation of the drawing]

The drawings show an embodiment of the hydraulic control mechanism for a rice transplanter according to the present invention, in which Fig. 1 is a side view of the spool movement check section, Fig. 2 is a cross-sectional plan view of the control valve, and Fig. 3 is a part of the control valve. Fig. 4 is a longitudinal sectional front view of the control valve, Fig. 5 0) to (c) are enlarged plan views of main parts showing various spool displacement states, Fig. 6 is an overall side view of the rice transplanter, Fig. Figure 7 is a perspective view of the automatic control mechanism.
′. (3)...Seedling planting device, (4)...Hydraulic cylinder, (6)...IIJill valve, (6
)...Sensor float, (b)...
Spool, prisoner...underlap part, +ILl
Pump port oil chamber, (b) Drain port oil chamber, (O) Cylinder port oil chamber, (e) Gap, ( f)...Gap,
N: Neutral position, (1: Raised position,
(a)...Automatic control position, f→...Forced rise position. Agent Patent Attorney Shua Kitamura 2

Claims (1)

[Claims] The seedling planting device (3) is operated by supplying and draining pressure oil to the single-acting hydraulic cylinder (4), which is controlled by a spool-type three-position switching control valve (5), and by shutting off the oil supply and drain. In addition to lifting and lowering operation and fixing, the spool (
12) attached to the seedling planting device (3).
The hydraulic control mechanism of the rice transplanter is configured to switch and operate based on the vertical movement detection of (6) to stably maintain the ground level of the seedling planting device (3), the spool (5) of the control valve (5) 12), a parallel step-like underlap part (A) that acts between the neutral position (N) and the raised position (U) of the seedling planting device is formed, and this underlap part (A
), the pump port oil chamber (a) and cylinder port oil chamber (c) are underlapping (A).
The pump port oil chamber (a) and the drain port oil chamber (b) communicate with each other through a small gap (f), and In the operating range of the underlap section (A) on the upward side of the seedling planting device, the pump port oil chamber (a) and the cylinder port oil chamber (c) are connected to a minute gap (e) formed around the underlap section (A).
) and communicates with the pump port oil chamber (a
) and the drain port oil chamber (b) are shut off, and the spool (
12) In the vicinity of the stroke end toward the upward side of the seedling planting device, the pump port oil chamber (a) is located at the underlap portion (
The length of the underlap portion (A) is set so that short-circuit communication is established with the cylinder port oil chamber (c) without going through the spool (12), and the lever (21) for manually operating the spool (12) is automatically operated. When in the control position (a), the spool (12) moves near the upward stroke end to prevent the pump port oil chamber (a) from being shortened and communicated with the cylinder port oil chamber (c), and the lever A hydraulic control mechanism for a rice transplanter, which is provided with a restraining member (23) that allows the spool (12) to move to the upward stroke end when (21) is in the forced upward position (c).