JPH0438653Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of a shock absorber in an agricultural machine.

[Problems that conventional technology and ideas try to solve]

In agricultural machinery such as rice transplanters, as disclosed in the prior art Utility Model Publication No. 57-23710, etc., a seedling planting device is connected to a traveling machine via a link mechanism so that it can be raised and lowered freely. A hydraulic actuator is installed between a traveling body and a link mechanism as an automatic control device that controls a seedling planting device so that it can follow the field at a substantially constant height.

In this case, because the sensor that detects the vertical distance between the field scene and the seedling planting device is too sensitive, a hunting phenomenon may occur in the entire automatic control system including the hydraulic actuator.

In order to prevent this, conventionally, a hydraulic shock absorber (damper) was installed between the traveling aircraft and the link mechanism, but the length of the hydraulic shock absorber was It had the drawbacks of being long, requiring high manufacturing precision, and being expensive.

The present invention aims to solve this technical problem and provide a shock absorbing device with a simple structure and higher shock absorbing capacity.

[Means to solve the problem]

In order to achieve this purpose, the present invention provides an actuator such as a hydraulic type for driving the link mechanism up and down between a traveling machine such as a rice transplanter and a link mechanism that lifts and lowers the agricultural machine of the seedling planting device. , a lifting mechanism comprising a compression spring that supports the load of the agricultural machine and is arranged in series, wherein the actuator is provided with a protruding rod that moves integrally along the direction of expansion and contraction of the actuator; The end face of a slidably fitted cylindrical elastic body made of rubber or the like is supported by the compression spring loosely fitted to the rod, while the outer circumferential surface of the cylindrical elastic body and along the outer circumferential surface The inner circumferential surface of the cylindrical case into which the cylindrical elastic body is fitted is placed between the outer circumferential surface of the rod and the inner circumferential surface of the cylindrical elastic body, facing each other in the moving direction of the rod when the actuator is actuated. The rod is formed with a tapered surface inclined with respect to the axis of the rod so as to increase the generated frictional force.

〔Example〕

Next, an embodiment in which the present invention is applied to a riding type rice transplanter will be described. In the figure, 1 indicates a traveling machine body, and the traveling machine body 1 includes a body frame 2, two front wheels 3 attached to the lower front surface of the body frame 2, 3 and two rear wheels 5, 5 attached to the lower surface of the rear via chain cases 4, 4, the upper surface of the vehicle body frame 2 is equipped with a control seat 6 and a steering handle 7, and the upper surface of the front portion of the vehicle body frame 2. The engine 8 drives the wheels 3 and 5 to move forward.

Reference numeral 9 indicates a seedling planting device which is attached to the rear of the traveling body 1 so as to be vertically movable via a parallel link mechanism 10 consisting of one top link 41 and two lower links 42, 42. The device 9 includes a transmission case 11, and planting cases 13, 13, 13 attached to both left and right sides of the transmission case 11 at appropriate intervals in the lateral direction via pipe-shaped support members 12, 12.
Float 14, 1 arranged on the bottom of each planting case
5, 14, and a seedling platform 16 whose upper end is inclined so as to approach the traveling body 1, and a vertically swinging type seedling planting mechanism 17 is provided at the rear end of each planting case.
Further, a single-acting hydraulic actuator 18 is provided between the traveling body 1 and the parallel link mechanism 10 for raising and lowering the seedling planting device 9 with respect to the field.

In this case, in another embodiment, the seedling planting device 9 is attached to the traveling body 1 so that it cannot move up and down, while the front wheels 3 and/or the rear wheels 5 of the traveling body 1 are moved up and down by a hydraulic actuator 18. The seedling planting device 9 may be moved up and down with respect to the field.

Each planting case 13, 1 in the seedling planting device 9
A horizontal shaft 19 is rotatably supported on the lower surface of 3, 13, and each float 14, 15, 14 is attached to the tip of an arm 20 that protrudes from the horizontal shaft 19 at each float location. , each float 14, 15, 14 is pivoted to its pivot pin 21 so that its front part can move up and down, and the horizontal shaft 19 is rotated by a lever projecting upward from the horizontal shaft 19, so that each float 14, 15, 14 can be moved to its pivot pin 21. It is configured to move up and down at 21 points to adjust the planting depth of seedlings.

This lever is configured so that it can be locked at any rotational position on a guide locking body protruding from the transmission case 11 or the like.

In addition, in the hydraulic circuit 23 extending from the hydraulic pump 24 to the hydraulic actuator 18 in the traveling aircraft 1, there is a neutral position where the movement of the spool 27 with a spring 26 cuts off the flow of hydraulic pressure into and out of the hydraulic actuator 18; A switching valve 28 is provided that can be switched between three positions: a raised position for supplying hydraulic pressure and a lowered position for releasing hydraulic pressure from the hydraulic actuator 18. The spool 27 of the switching valve 28 is rotated at its base end by its spring 26. It comes into contact with one end of the bell crank lever 29 which is freely pivoted,
One end of a wire 31 inserted into a cable conduit 30 is attached to the other end of the bell crank lever 29.
One end of the cable conduit 30 is attached to the receiving bracket 3 with respect to the traveling aircraft 1.
It is attached to 2.

Reference numeral 33 indicates a sensor mechanism disposed at the lower part of the transmission case 11 in the seedling planting device 9, and the sensor mechanism 33 includes a pair of left and right parallel link mechanisms 3, which are attached to the transmission case 11 and extend in the front direction of the traveling body.
4, 34, and the parallel link mechanism 34 and the horizontal shaft 19 are interlocked with the rotation of the horizontal shaft 19 so that the bracket 35 connects to the pivot pin of the float 15. The bracket 3 is interlocked and connected via a link mechanism 26 so that it moves up and down in the same direction and by the same amount as the up and down movement of the bracket 21.
A sensor 38 is provided on the front surface of the vehicle 5 so as to be movable up and down via a sensor parallel link mechanism 37 consisting of a pair of equal-length links extending perpendicular to the traveling direction of the traveling aircraft. is rotatably provided with a trochanter that contacts the upper surface of the central float 15, while a wire receiving fitting 39 is provided on the bracket 35, and the other end of the cable conduit 30 is fixed to the wire receiving fitting 39. The other end of the wire 31 in the cable conduit 30 is connected to the sensor parallel link mechanism 3.
A seedling planting mechanism 9 is attached to the extension of the upper link 8 at 7.
The spool 27 of the switching valve 28, which is interlocked with one end of the wire 31, is engaged in a neutral position when the switch is at a predetermined height position relative to the field 40.

Note that a buffer spring whose spring constant is larger than that of the spring 26 of the spool 27 is provided in the middle of the wire 31 .

The cylinder 43 of the hydraulic actuator 18 is
A pin 44 is pivotally attached to the traveling body 1, and the cylinder 43
The tip of the piston rod 45, which is slidably retractable, is attached to a bifurcated bracket 47 projecting downward from the top link 41 of the parallel link mechanism 10, via a shock absorbing device 46 of the present invention.

The inner circumferential surface of the cylindrical case 48 of the shock absorber 46 shown in FIG. The protruding support pins 49, 49 are connected to the links 50, 50 and the pin 51,
51, the rod 45' is rotatably connected to the bifurcated bracket 47, and the rod 45' is attached to the cylindrical case 4 with the opening of the cylindrical case 48 facing the cylinder 43.
It is fitted loosely and penetratingly at the bottom of 8.

The cylindrical elastic body 52 made of rubber or the like to be fitted into the cylindrical case 48 is also formed in the shape of a truncated cone so that its outer circumferential surface comes into contact with the tapered inner circumferential surface of the cylindrical case 48. However, the inner diameter surface of the cylindrical elastic body 52 is fitted so as to be substantially in contact with the outer circumferential surface of the rod 45'.

A contact plate 54 is slidably fitted into this rod 45' between a collar 53 fixed to the proximal end thereof and an end face of the cylindrical elastic body 52 inside the case 48 facing the collar 53. A compression spring 55 is installed between the contact plate 54 and the collar 53, and the seedlings are inserted through the compression spring 55 supported by the collar 53 of the rod 45', the cylindrical elastic body 52, and the cylindrical case 48. In addition to supporting the load of the implantation device 9, when the actuator 18 is activated, the rod 4
In response to the protruding movement of the cylindrical elastic body 5', the compression spring 55 presses the end face of the cylindrical elastic body 52 to elastically deform it.

At this time, the cylindrical elastic body 52 is supported by the inclined tapered surface of the inner surface of the cylindrical case 48 (the surface that gradually tapers toward the front in the moving direction of the rod 45') and the bottom surface. Therefore, the reaction force on the inclined tapered surface acts perpendicularly to the tapered surface, and a component of the reaction force is generated in the radially inward direction of the rod 45'. Due to this force,
By exerting a wedge effect in which the pressure exerted by the inner circumferential surface of the cylindrical elastic body 52 against the outer circumferential surface of the rod 45' increases, there is a gap between the inner circumferential surface of the cylindrical elastic body 52 and the outer circumferential surface of the rod 45'. The structure is such that as the rod 45' moves toward the case 48, the frictional force generated in the opposite direction increases.

In addition, as a matter of material mechanics, when the outer diameter surface and inner diameter surface of a cylindrical elastic body such as rubber (Poisson's ratio is said to be approximately 0.5) are rigid and immovably restrained, the cylindrical When an external force acts on the end face of an elastic body, the strain in the radial direction of the cylindrical elastic body is restrained, and a predetermined stress is applied in the radial direction. This also applies to the case of the cylindrical case 48, so
The sum of this stress and the stress due to the reaction force (radially inward direction, external pressure on the outer peripheral surface of the cylindrical elastic body) acts in the inner diameter (radial) direction of the cylindrical elastic body 52, and the elastic The rod 45' is better supported when the elastic body is supported by a cylindrical case having a tapered slanted surface such as a frustoconical shape as an inner circumferential surface than when the body is housed in a normal cylindrical case.
It will be appreciated that the pressure acting radially inward on the outer circumferential surface increases.

In this configuration, rice planting work uses the seedling planting device 9,
After descending until each of the floats 14, 15, 14 touches the field, the traveling machine 1 is moved forward. At this time, the switching valve 28, which is connected via the wire 31 to the sensor 38 in contact with the float 16, is in the neutral position, so the seedling planting device 9 does not move up or down.
When the height between the seedling planting device 9 and the field scene 40 becomes higher than a predetermined value, the front part of the central float 16 is displaced away from the seedling planting device 9, and the sensor 38 in contact with it is lowered. move wire 31
Since the tension on spring 2 is relaxed, the switching valve 28
At 6, the hydraulic actuator 1 switches to the lower position.
The rod 45' at 8 moves in the direction of the cylinder 43, and the seedling planting device 9 is lowered toward the field.
When the predetermined height is reached, the switching valve 28 becomes the neutral position and the lowering of the seedling planting device is stopped.

Further, when the height between the seedling planting device 9 and the field scene 40 becomes lower than a predetermined value, the front part of the center float 15 is displaced to approach the seedling planting device 9, and the sensor 40 that comes into contact with this is moved. rises and pulls the wire 31, the switching valve 28 switches to the raised position and pushes out the rod 45', the seedling planting device 9 rises, and when it reaches a predetermined height, the switching valve 28 returns to the neutral position. Then the seedling planting device will stop rising.
Thereby, the height of the seedling planting device 9 relative to the field scene 40 can be automatically controlled to a predetermined value.

When the seedling planting device 9 descends in this way, the cylindrical elastic body 5 in the cylindrical case 48 in the buffer device 46
2 is a cylindrical case 4 that supports the load of the table 9;
8 and a spring 55, and the cylindrical elastic body 52 is pressed via the contact plate 54.

At this time, the outer circumferential surface of the cylindrical elastic body 52 is pressed against the inclined inner circumferential surface of the cylindrical case 48, and the cylindrical elastic body 52 becomes more easily deformed in the inner diameter direction (the inner diameter is When it is restrained so that it cannot deform, a so-called wedge effect is exerted in which the stress (pressure) in the radial inward direction increases. Therefore, the inner diameter surface of the cylindrical elastic body 52 presses the outer peripheral surface of the rod 45', and the rod 4
A frictional force is generated between the outer circumferential surface of the elastic body 5' and the inner diameter surface of the elastic body 52 in a direction opposite to the moving direction of the rod 45', thereby slowing down the axial moving speed of the rod 45' and causing compression. Hunting phenomenon caused by vibration of the spring 55 can be prevented.

As shown in FIG. 6, the outer periphery of the cylindrical elastic body 52' that is slidably fitted onto the rod 45' is shaped like a drum, with smaller diameters at both left and right ends and larger diameters at the center. , a cylindrical case 48' with openings at both ends that supports the outer circumference of the cylindrical elastic body 52',
By forming the inner circumferential surface into a drum-shaped so-called tapered surface similar to that described above, the same wedge effect as in the previous embodiment can be exerted in any direction of the reciprocating movement of the rod 45'. You can slow down your movement speed.

At this time, an abutting plate 5 that is slidable along the rod 45' is inserted into the left and right end openings of the cylindrical case 48'.
4', 54'', while these contact plates 54',
54'' and the tsuba 5 fixed to the rod 45' at an appropriate distance.
By interposing the compression springs 55' and 55'' between the rods 3' and 53'', the wedge effect can be further exerted when the rod 45' moves in either the left or right direction (the direction of protrusion and retraction). It may be possible to configure it.

[Functions and effects of the invention]

In summary, the present invention consists of a rod that is movable along the axis by a hydraulic actuator in an agricultural machine, and a cylindrical elastic body made of rubber or the like that is slidably fitted on the rod. In order to support the elastic body, a cylindrical case with a tapered inner surface inclined with respect to the axis of the rod is arranged on the outer circumference of the elastic body, and a compression spring fitted on the rod presses against the end surface of the cylindrical elastic body. The load of agricultural machinery such as seedling planting equipment is supported by the actuator. When the rod is operated, the frictional force generated between the outer circumferential surface of the rod and the inner circumferential surface of the cylindrical elastic body opposite to the direction of movement of the rod increases, and this causes vibrations in the automatic control system of agricultural machinery, etc. The dry frictional force generated between the outer circumferential surface of the moving rod in the system and the inner circumferential surface of the cylindrical elastic body fitted therein can reduce the moving speed or momentum of the rod, thereby preventing the hunting phenomenon in the vibration system.

In this way, the inner circumferential surface of the cylindrical case has a tapered shape that narrows toward the front in the direction of movement of the rod, so that the cylindrical elastic body supported by the inner circumferential surface of the cylindrical case prevents the rod from moving. As the stress increases toward the inner diameter of the elastic body due to the wedge action, the frictional force against the outer circumferential surface of the rod increases, compared to when the inner circumferential surface of the cylindrical case is approximately parallel to the axis of the rod. The generation of the frictional force becomes more reliable, for example, when the agricultural machine is left unused for a long time and the rubber elasticity of the cylindrical elastic body has deteriorated, or on the other hand, when the inner diameter of the cylindrical elastic body is worn out due to frequent use. Even when the rod becomes large, there is no problem that the frictional force against the rod becomes insufficient or uncertain. Therefore, the structure is extremely simple and has the effect of being realized at low cost.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a side view of a riding rice transplanter, Fig. 2 is a plan view, Fig. 3 is an explanatory diagram of the automatic height control system of the seedling transplanting device, and Fig. 4 is an illustration of the automatic height control system of the seedling transplanter. A side view of the shock absorber; FIG. 5 is a sectional view taken along the line - in FIG. 4;
FIG. 6 is a sectional view of a main part of another embodiment. DESCRIPTION OF SYMBOLS 1... Traveling body, 9... Seedling planting mechanism, 10... Link mechanism, 18... Actuator, 43... Cylinder, 45'... Rod, 46... Shock absorber, 4
8, 48'... Cylindrical case, 52, 52'... Cylindrical elastic body, 54, 54', 54''... Contact plate, 53,
53', 53''...Tsuba, 55, 55', 55''...Compression spring.

Claims (1)

[Scope of utility model registration request] Between a traveling machine such as a rice transplanter and a link mechanism for raising and lowering the agricultural machine of the seedling planting device, there is provided an actuator, such as a hydraulic actuator, for driving the link mechanism up and down, and a compressor for supporting the load of the agricultural machine. In an elevating mechanism in which a spring is arranged in series, a rod that moves integrally with the actuator in the direction of expansion and contraction is provided protruding from the actuator, and a rod made of rubber or the like is slidably fitted onto the rod. The end face of the cylindrical elastic body is supported by the compression spring that is loosely fitted to the rod, while the outer peripheral surface of the cylindrical elastic body and the cylinder in which the cylindrical elastic body is fitted along the outer peripheral surface are supported. and the inner peripheral surface of the shaped case,
A tapered surface inclined with respect to the axis of the rod so as to increase the frictional force generated between the outer circumferential surface of the rod and the inner circumferential surface of the cylindrical elastic body opposite to the direction of movement of the rod when the actuator is actuated. A shock absorbing device for a lifting mechanism of an agricultural machine, characterized in that it is formed as follows.