JP2548365Y2 - Hydraulic cylinder - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic cylinder, and more particularly to a hydraulic cylinder of a two-pressure control type capable of controlling two pressures with a single cylinder.

[0002]

2. Description of the Related Art FIG. 8 is an explanatory view of a configuration of a conventional hydraulic cylinder, FIG. 9 is a left side view of FIG. 8, and FIG. 10 is a connection diagram of a hydraulic circuit. 8 to 10, reference numeral 1 denotes a hydraulic cylinder, 3 denotes a cylinder, and 7 denotes a rod. 31 is a sliding hole of the cylinder 3, 43 is a check valve, 43d is a seat, and 44 is a fixed throttle. r is an oil passage, R is the inner wall of the cylinder 3 and the rod 7
This is an oil chamber formed by a gap between A in FIG. 10 is an accumulator.

In the conventional hydraulic cylinder 1 having such a configuration, pressure oil is sent into an oil chamber R inside the cylinder 3 by the gas pressure sealed in the accumulator A. Rod 7
Is extended in the sliding hole 31 of the cylinder 3 when it is extended, the fixed throttle 44 works to gradually extend at a low speed.
The rod 7 is pressurized by pressure oil in the sliding hole 31 and is always kept in the extended state. If the tip of the rod 7 hits a light obstacle during extension, the pressure in the oil chamber R increases, and the rod 7 operates so as to maintain the extension state by this resistance. Further, when the rod 7 contracts due to a strong external force, the pressure in the oil chamber R of the cylinder 3 increases, and when the pressure in the oil chamber R exceeds a certain pressure, the check valve 43 opens and the pressure oil flows backward and contracts.

The characteristics of the conventional hydraulic cylinder 3 are shown by a solid line c in FIG. For the origin 0 on the horizontal axis, the extension end position of the stroke S when the rod 7 is extended is selected. As shown in the drawing, the pressure P when the rod 7 contracts in the sliding hole 31 and the backflow of the hydraulic pressure is started is the minimum value, and then the pressure gradually increases at the inclination angle of θ and the stroke of the rod 7 When S is at the extension end position, the closed circuit using the accumulator A as the hydraulic pressure source is compressed most and the pressure P becomes the maximum value.

[0005]

As described above, in the conventional hydraulic cylinder, the pressure P has a minimum value at the position where the rod 7 is at the extended end position of the stroke S. Therefore, when applied to a cultivator for agricultural use, for example, the rod 7 may expand and contract due to a change in soil hardness and the presence or absence of a small obstacle such as a root of a large crop. For this reason, deep and uneven unevenness occurs in the plowing of the soil in the fields, and the tillage becomes inappropriate for the type of crop, which may adversely affect the harvest. If an accumulator A having a large gas pressure and a high rated value is used to prevent uneven plowing, a robust cylinder or frame corresponding to the accumulator A must be used. As a result, there is a problem that the manufacturing cost is higher than that of a mechanical device using a leaf spring or the like, and as a result, the product becomes weak in competitiveness.

The present invention has been made in order to solve such a problem of the conventional hydraulic cylinder. When a relatively high load is applied to a relatively small load and a load exceeding a certain value is applied. It is an object of the present invention to realize a two-pressure control type hydraulic cylinder in which two pressures can be controlled by a single single-acting cylinder in which a rod is rapidly contracted due to a low pressure.

[0007]

According to the present invention, there is provided a cylinder having a switching port formed on a side wall near an open end of a sliding hole and a connection port connected to a hydraulic pressure source provided on a closed end side; A communication passage that communicates with the connection port, a rod interposed and sliding on the open end side of the sliding hole, and a rod that is introduced by a hydraulic pressure introduced into an oil chamber formed between a sliding wall and a closing wall of the sliding hole. A check that has a piston that opens and closes the switching port by sliding in the sliding hole and a throttle that is built in the closed end side of the cylinder and that is provided between the connection port and the oil chamber to form a parallel circuit with each other A hydraulic cylinder comprising a valve and a relief valve.

[0008]

When the pressure oil is supplied to the oil chamber of the hydraulic cylinder, the rod is pushed by the piston and extends while sliding. When the extending rod approaches the extension end of the stroke, the switching port is closed, but at the same time, the flow path of the pressure oil replaces the flow path of the check valve, and the fluid resistance of the throttle acts on the pressure oil flowing into the oil chamber. Stops the stroke when it reaches the leftmost position. The extended state of the rod is maintained by the internal pressure of the sealed cylinder.

When a weak external force is applied to the rod in the extended state and pressed, the oil pressure in the oil chamber rises, the relief valve is activated, the pressure becomes high, and the rod is held near the extended end.
Further, when an external force is continuously applied to the rod and exceeds the set pressure, the pressure oil flows out of the relief valve. The rod contracts in response to the outflow. When the piston retracts together with the contracting rod and the rod opens the switching port, the pressure in the oil chamber drops sharply, and the rod contracts and the internal pressure drops to the accumulator pressure. When there is no external force applied to the rod, the rod slides toward the extended state again.

[0010]

Embodiment 1 FIG. 1 is an explanatory view of the configuration of an embodiment of the present invention, and FIG. 2 is a sectional view taken along line XX of FIG.
It is sectional drawing. In the drawings of the embodiment of the present invention, the same parts as those of the conventional apparatus are denoted by the same reference numerals, but there are some parts whose structures and functions are slightly different, so that the description will be overlapped but will be described in some detail.

1 and 2, reference numeral 1 denotes a hydraulic cylinder,
Reference numeral 2 denotes a main body of the hydraulic cylinder 1. The main body 2 includes a cylinder 3, a head cover 4, a rod cover 5, and a bypass pipe 6.
It is composed of Reference numeral 31 denotes a sliding hole provided in the cylinder 3, and reference numeral 32 denotes a switching port formed in a side wall near the front end. The hydraulic cylinder 1 is a so-called loose-ram (ram) type single-acting type, and hydraulic pressure is supplied to the head cover 4 side where the sliding hole 31 is opened and the rod cover 5 side is closed. 41 is a connection fitting attached to the outer periphery of the head cover 4, 42 is a relief valve, and 43 is a check valve provided with a throttle 44 in series. The connection fitting 41 constitutes a connection port for hydraulic pressure introduction, and is connected to the switching port 32 by the bypass pipe 6. The relief valve 42 and the check valve 43 are connected in parallel with each other.

Reference numerals 42a and 43a denote springs of the relief valve 42 and the check valve 43, 42b and 43b denote valve holders, 42c and 43c denote poppets and balls, and 42d and 43d denote valve seats (FIG. 2). 51 is a bearing provided on the rod cover 5, 52 is a rod packing, and 53 is a backup ring. 54 is a dust wiper, 55 is a screw, 5
6 is an O-ring. The rod cover 5 is connected to the open end of the cylinder 3 by screws 55, and the head cover 4 is fixed to the closed end by welding.

7 is a rod, 8 is a piston, 9 is a rod 7
And a universal joint for connecting the piston 8 to the piston. The rod 7 is interposed in the sliding hole 31 on the open end side, and the piston 8 is fitted on the closed end side. 81 is a sliding part on the outer periphery of the piston 8, and 82 is a hollow part. The sliding portion 81 is the switching port 32
, And in combination with the switching port 32, performs a valve function of opening and closing the flow path. The hollow portion 82 communicates with the relief valve 42, the check valve 43, and the switching port 32, and an oil chamber R is formed between the hollow portion 82 and the inner wall of the sliding hole 31 on the closed end side. The universal joint 9 is provided on the end face of the rod 7 in a "mushroom-like" shape.
Are engaged with a “T-shaped” groove 92 formed in the piston 8 and are slidably connected three-dimensionally.

Reference numeral 10 denotes a mounting hole provided in the main body 2 and the rod 9, r denotes an oil passage, and S denotes a stroke of the rod 7. The sliding portion 81 of the piston 8 opens and closes the switching port 32 near the left end of the stroke S.
To form a switching valve V.

The embodiment of the present invention described with reference to FIGS.
FIG. 3 shows a configuration applied to a two-bottom type tilling device incorporating a pair of bottoms, and FIG. 4 shows a connection diagram of a fluid circuit of the tilling device of FIG. 3 and FIG.
Is a tillage device. 61 is the frame of the tillage device 60, 6
2 is a connection part, 63 is a wheel. 64 is an arm, 65 is a bottom attached to the tip of both arms 64, 66 is an elevating shaft, 67 is a coulter, 68 is a spring mechanism.
A set is provided. The coulter 67 cuts the residue after tilling, and the spring mechanism 68 contracts when ascending to prevent breakage.

The two hydraulic cylinders 1 are provided with mounting holes 1
0 to each pair of frames 61 and arms 64,
Both bottoms 65 move up and down independently about the elevating shaft 66 in accordance with the expansion and contraction of each rod 7. A is an accumulator mounted on the frame 68, and M is a hydraulic gauge. Accumulator A
For example, a bladder type having an oil chamber partitioned by an elastic partition wall and an air chamber filled with compressible gas is used. The oil supply port of the accumulator A is connected to the connection fitting 41 of the two hydraulic cylinders 1. Then, the tillage device 60 is connected to a tractor (not shown) by a connecting portion 62.

The operation of the present invention having the above configuration will be described below. When the pressure oil is supplied to the oil chamber R of the hydraulic cylinder 1 by the pressure of the gas sealed in the accumulator A, the rod 7 on the rightmost (lower limit) side of the stroke S in FIG. Start sliding to the left. At this time, both ends of the piston 8 show the same pressure. In this state, most of the pressure oil flows directly into the oil chamber R through the switching port 32 through the bypass pipe 6, and the rod 7
With it, it slides and expands quickly.

When the sliding rod 7 approaches the left end (extended end) of the stroke S, the sliding portion 81 of the piston 8 reaches the switching port 32 and the opening is closed. For this reason, the pressure oil sent from the accumulator A flows into the oil chamber R through the flow path of the check valve 43 and the throttle 44. Since the fluid resistance of the throttle 44 acts on the pressure oil flowing into the oil chamber R via the check valve 43, the rod 7 slowly extends. The rod 7 further slides and reaches the leftmost position while slightly reducing the pressure, reaches the position of the extended end of the stroke, and stops. The rod 7 is held in an extended state by the pressure of the sealed oil chamber R.

On the other hand, the tillage device 60 is towed by a tractor which advances in the direction of a hollow arrow, and is towed while rotating the wheel 63 while contacting the ground surface. The two rods 7 connected to the rods 7 in the extended state via the arms 64, respectively.
The tip of two bottoms 65 is buried at a certain depth in the ground,
The soil excavated in two rows is swept obliquely backward along the inclined surface of the bottom 65, and the fields are plowed. The tip of the bottom 63 during cultivation buried in the ground may come into contact with the roots and plants of the crop left after harvesting, or a rather large soil mass, or a fixed object such as a large hard stone.

When a weak external force is transmitted to and pressed against the extended rod 7 in contact with the roots or soil masses of weeds or small plants, the oil pressure in the oil chamber R inside the piston 8 rises and resists the external force. The bottom 65 continues tilling as it is. When it comes into contact with a fixed object such as a hard stone, the internal pressure continuously increases. The upper limit value of the oil pressure in the raised oil chamber R is the relief valve 42
When the pressure exceeds the set pressure, the relief valve 42 opens and flows backward to the accumulator A side, and the internal pressure decreases.

When an external force is continuously applied to the rod 7 and the pressure oil flows backward from the relief valve 42, the rod 7 contracts in accordance with the outflow amount. When the piston 8 moves together with the contracting rod 7 and the sliding portion 81 passes the switching port 32, the pressure of the oil pressure in the oil chamber R sharply decreases. Since the oil pressure in the oil chamber R decreases to the pressure of the accumulator A, the rod 7 contracts, and the bottom 65 rotates about the elevating shaft 66 as a fulcrum and rises.

When the external force applied to the rod 7 disappears, the rod 7 slides again toward the extension end and extends. When the piston 8 toward the extension end closes the switching port 32, the check valve 43 is pushed open as described above. Then, the pressure oil flows into the oil chamber R, the rod 7 stops again at the extended end, and the extended state is maintained. A characteristic diagram of the hydraulic pressure in the oil chamber R at this time is shown in FIG.

P1 and P2 in FIG. 5 are set pressures of the accumulator A and the relief valve 42. Further, in the stroke S of the rod 7, the range of Sa is a low pressure region and the range of Sb is a high pressure operation region. In this way, the tillage is continued against the contact object having a weak force with the increased internal pressure, and the switching port is opened for a large obstacle, and the bottom 65 is rapidly raised to avoid the obstacle. As a result, the tractor that has pulled the tillage device 60 can continuously till the soil such as the fields without stopping, without stopping.

FIG. 6 is a structural explanatory view of a main part of the second embodiment of the present invention. In FIG. 6, reference numeral 42e denotes an adjusting screw of the relief valve 42, 42f denotes a nut, and 42g denotes an O-ring. In the second embodiment of the present invention, the spring pressure of the spring 42a is configured to be adjustable by the adjustment screw 42e shown. As a result,
By turning the adjusting screw 42e, the seat 4 is held via the holder 42b.
The operating pressure of the relief valve 42 can be arbitrarily set to a value by changing the force of the poppet 42c pressed against 2d.
According to the second embodiment of the present invention having the adjustable relief valve 42, the pressure can be set to correspond to the strength of obstacles, the difference in soil quality, and the like, which is extremely convenient.

FIG. 7 is an explanatory view of the configuration of a third embodiment of the present invention. In the third embodiment, the accumulator A of the first embodiment is used.
Instead, a hydraulic source O of variable capacity or constant capacity is used. Reference numeral 11 denotes a relief valve provided at the tank port t. According to the third embodiment, a large hydraulic device using the hydraulic pressure source O can be configured.

In the above embodiment, the case where the bypass pipe 6 is attached to the side surface of the main body 2 has been described as an example. However, the switching port 32 is connected to the accumulator A or the hydraulic power source O by the internal flow path of the cylinder 3 or the tube. You may communicate with.

[0027]

According to the present invention, a cylinder having a switching port formed on a side wall near an open end of a sliding hole and a connection port connected to a hydraulic power source provided on a closed end side, and a switching port and a connection port are provided. The rod is slid together with the rod by hydraulic pressure introduced into an oil chamber formed between the communicating flow path, the rod interposed and sliding on the open end side of the sliding hole, and the closing wall of the sliding hole. A check valve and a relief valve, which are provided between the connection port and the oil chamber and are provided between the connection port and the oil chamber and constitute a parallel circuit with each other; And a hydraulic cylinder comprising:

As a result, a single hydraulic cylinder capable of controlling two high and low pressures can be constituted by the initial region Sa and the final region Sb of the stroke S of the rod 7. Therefore, it is possible to realize a small and compact hydraulic device that performs two functions with one hydraulic cylinder. Further, since the check valve and the relief valve having the throttle are built in the inside of the hydraulic cylinder, a hydraulic drive device can be configured only by connecting a power package such as an accumulator. Therefore, the piping work of the fluid circuit is extremely easy, the number of assembling work steps is small, and the occurrence of oil leakage accidents can be reduced.

Therefore, according to the present invention, it is possible to provide a hydraulic cylinder suitable for application to a tillage device which is inexpensive in manufacturing cost and compact.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration of a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line XX of FIG.

FIG. 3 is a configuration explanatory diagram of an application example of the first embodiment of the present invention;

FIG. 4 is a connection diagram of the hydraulic circuit according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of characteristics of the hydraulic cylinder according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram of a configuration of a main part of a second embodiment of the present invention.

FIG. 7 is a connection diagram of a hydraulic circuit according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of a configuration of a conventional hydraulic cylinder.

FIG. 9 is a left side view of FIG. 9;

FIG. 10 is a connection diagram of a hydraulic circuit of a conventional hydraulic cylinder.

FIG. 11 is a diagram illustrating characteristics of a conventional hydraulic cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic cylinder 3 Cylinder 7 Rod 8 Piston 31 Sliding hole 32 Switching port 41 Connection fitting (Connection port) 42 Relief valve 43 Check valve 44 Restrictor 81 Sliding part R Oil chamber S Stroke V Switching valve A Accumulator O Hydraulic source

Claims (1)

(57) [Scope of request for utility model registration] 1. A cylinder having a switching port formed on a side wall near an open end of a sliding hole and having a connection port connected to a hydraulic pressure source on a closed end side, and a communication connecting the switching port and the connection port. The rod is slid together with the rod by hydraulic pressure introduced into an oil chamber formed between the flow path, a rod interposed and slidably provided on the open end side of the slide hole, and a closed wall of the slide hole. A check valve having a piston that slides in the moving hole to open and close the switching port, a throttle built in the closed end side of the cylinder, provided between the connection port and the oil chamber, and forming a parallel circuit with each other; A hydraulic cylinder comprising a relief valve.