JPH11230117A - Hydraulic cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent incidence of abnormal sounds caused by restriction noises when a cushion is operated in the vicinity of the time of the maximum elongation or the maximum compression, and easily machine an oil passing hole. SOLUTION: In this cylinder, a supply/exhaust port and a port 25 and the like to communicate this supply/exhaust port with a pressure chamber are formed in a cylinder head 21 or a cylinder bottom. In this case, an annular guide 33 is projected on the inner circumference of the port 25 and the like, an oil passing hole 26 and the like bypassing the port 25 and the like in the guide 33 are formed in the cylinder head 21 or the cylinder bottom, this oil passing hole 26 and the like are opened in the port 25 and the like through a groove arranged in the inner circumference of the port 25 and the like, or the oil passing hole 26 and the like are formed in a slant direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic cylinder used as an actuator in a construction machine and other industrial machines, and more particularly to a hydraulic cylinder which exerts a cushion at the time of maximum extension or maximum compression.

[0002]

2. Description of the Related Art In general, a hydraulic cylinder used as an actuator is usually provided with a cushion device for preventing a piston from suddenly colliding with a cylinder head or a cylinder bottom at the time of maximum extension or compression.

For example, a hydraulic cylinder shown in FIG. 8 is known as a conventional hydraulic cylinder.

The hydraulic cylinder is a cylinder head body 1
The end of the cylinder tube 3 is fitted and fixed to the outer periphery of the fitting portion 2 provided at the end of the cylinder tube 3. A piston rod 5 is movably inserted into the cylinder tube 3 via a piston 4, and the piston 4 Defines a head side pressure chamber 6 in the cylinder tube 3. Further, the cylinder head 1 has a supply / discharge port 7a connected to a hydraulic pressure source, a port 7b communicating the supply / discharge port 7a with the head side pressure chamber 6, and a port 7b.
b orifice 8 having an orifice 9 for directly connecting the supply / discharge port 7a to the head side pressure chamber 6 bypassing the b.
Are formed. Further, a seal 11 and a cylindrical cushion ring 10 are fitted around the outer periphery of the piston rod 5 close to the piston 4. For this reason, at the time of the extension operation, the piston 4 moves to the left in FIG. 8, and the hydraulic oil in the head side pressure chamber 6 is discharged to the supply / discharge port 7a via the port 7b and the oil communication hole 8, and further returned to the external tank. . As shown, when the cushion ring 10 reaches the vicinity of the maximum extension, the cushion ring 10 enters into the port 7b, and the hydraulic oil in the head side pressure chamber 6 is supplied to the cushion ring 1
0 and the inner periphery of the port 7b and the oil passage 8
Flows out to the supply / discharge port 7a through the gap, the pressure in the head side oil chamber 6 rises due to the flow resistance between the gap and the orifice 9, and the piston 4 decelerates. Is prevented.

[0005]

Although the above-mentioned hydraulic cylinders are not particularly defective in function, the following problems are desired to be improved.

First, an oil passage 8 is formed to directly connect the cylinder head side pressure chamber 6 to the supply / discharge port 7a, and the high pressure hydraulic oil in the head side pressure chamber 6 is jetted directly to the supply / discharge port 7a when the cushion is operated. Therefore, abnormal noise is generated at the time of ejection. This is because the distance between the outlet of the orifice 9 and the wall S of the supply / discharge port 7a is long, and the pressure difference increases due to an increase in the flow velocity of the liquid passing through the orifice 9, which is contained in the oil. The rapid expansion of the minute bubbles generates a throttle sound, and this throttle sound is transmitted to an external piping line to generate abnormal noise.

Second, since the oil through hole 8 is formed to be parallel and long so as to bypass the port 7b, the processing of the oil through hole 8 and the orifice 9 becomes a deep hole, which is difficult. In particular, if the rigidity of the drill for performing deep hole drilling is small, it is difficult to obtain the processing accuracy of the orifice 9 and it may cause breakage such as breakage of the drill.

Although the structure shown in FIG. 8 is a cushion structure at the time of extension operation, a similar structure is adopted also at the cylinder bottom side, and the same abnormal noise is generated at the time of compression operation, and it is difficult to machine the oil through hole. The problem has arisen.

Accordingly, an object of the present invention is to provide a fluid pressure cylinder which can prevent generation of abnormal noise due to a throttle sound at the time of a cushion operation in the vicinity of a maximum extension or a maximum compression, and can facilitate machining of an oil through hole. It is to be.

[0010]

According to one aspect of the present invention, a cylinder head and a cylinder bottom are connected to both ends of a cylinder tube, and a piston is provided in the cylinder tube through a piston. The rod is movably inserted, the piston partitions the head side pressure chamber and the bottom side pressure chamber in the cylinder tube, and the cylinder head has a supply / discharge port connected to a hydraulic pressure source and this supply / discharge port connected to the head side pressure chamber. In a fluid pressure cylinder in which a port communicating with the port is formed and a cushion ring fitted to the port is provided on the outer periphery of the piston rod in the vicinity of the most extended position, an annular guide is protruded from the inner periphery of the port. A groove is formed closer to the supply / discharge port than the guide, and an oil through hole is formed in the cylinder head for communicating the head side pressure chamber with the groove. .

Another means is that a cylinder head and a cylinder bottom are connected to both ends of a cylinder tube, and a piston rod is movably inserted into the cylinder tube via a piston. A pressure chamber and a bottom pressure chamber are defined, and a supply / discharge port connected to a hydraulic pressure source and a port connecting the supply / discharge port to the bottom pressure chamber are formed at the cylinder bottom. In a fluid pressure cylinder having a projection fitted to the port near compression, an annular guide is protruded on the inner periphery of the port, and a groove is formed near the supply / discharge port from the guide, and the cylinder is An oil passage hole is formed in the bottom for communicating the bottom-side pressure chamber with the groove.

In each of the above-mentioned means, it is preferable that the oil passage is formed in a horizontal or oblique direction and an orifice is provided in the middle.

[0013] Similarly, it is preferable that the oil passage is formed of a chalk formed in a horizontal direction or an oblique direction.

Similarly, the groove is preferably a single annular groove or a plurality of spaced grooves.

Similarly, the inner periphery of the groove is preferably formed in a rectangular, V-shaped or U-shaped cross section.

Still another means of the present invention is that a cylinder head and a cylinder bottom are connected to both ends of a cylinder tube, and a piston rod is movably inserted into the cylinder tube via a piston. A head-side pressure chamber and a bottom-side pressure chamber,
The cylinder head has a supply / discharge port connected to the hydraulic pressure source and a port connecting the supply / discharge port to the pressure chamber on the head side. In the fluid pressure cylinder, an annular guide protrudes from the inner periphery of the port,
An oblique oil through-hole communicating the head-side pressure chamber and the port is formed in the cylinder head so as to bypass the guide inner port.

According to another aspect of the present invention, a cylinder head and a cylinder bottom are connected to both ends of a cylinder tube, and a piston rod is movably inserted into the cylinder tube via a piston. A head-side pressure chamber and a bottom-side pressure chamber,
A supply / discharge port connected to a hydraulic pressure source and a port connecting the supply / discharge port to the bottom side pressure chamber are formed on the cylinder bottom, and a projection that fits into the port near the most compression is formed at the end of the piston rod. In the provided hydraulic cylinder,
An annular guide is protrudingly provided on the inner periphery of the port, and an oblique oil through hole communicating the bottom side pressure chamber and the port is formed in the cylinder bottom so as to bypass the guide internal port. Features.

In the above case, the oil through hole may have an orifice in the middle, or the oil through hole may be made of chalk.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hydraulic cylinder according to the present invention will be described with reference to a hydraulic cylinder shown in FIG. Both ends of the cylinder tube 20 are fitted and fixed to a cylinder head 21 serving as a cap and a cylinder bottom, and the cylinder tube 2 is fixed.
A piston rod 23 is movably inserted into the cylinder 0 through a piston 22, and an end of the piston rod 23 slidably penetrates the cylinder head 21 via a seal.

The piston 22 defines a head-side pressure chamber 46 and a bottom-side pressure chamber in the cylinder tube 20. The head-side pressure chamber 46 is provided with a supply / discharge port 24, a port 25, and an oil passage 26 provided in the cylinder head 21. Through an external hydraulic source.

A seal 27 and a cylindrical cushion ring 28 are fitted around the outer periphery of the piston rod 23 close to the piston 22.
Penetrates into the port 25.

The cylinder head 21 comprises a head body 29 and a fitting portion 30 projecting from an end of the head body 29.
A supply / discharge port 24 communicating with a hydraulic pressure source is formed in the head main body 29, and a port 25 for communicating the supply / discharge port 24 with the head side pressure chamber 24 between the head main body 29 and the fitting portion 30.
Is formed.

The above configuration is basically the same as the prior art, but the present invention has the following specific configuration.

That is, a thick portion, which is an annular guide 33 for fitting the cushion ring 28, is protruded from the inner periphery of the pressure chamber 24 side end of, for example, the lateral port 25 formed in the fitting portion 30. A small-diameter port 33a communicating with the port 25 is formed on the inner periphery of the oil passage. Further, the fitting portion 30 bypasses the port 33a of the guide 33 and a groove 32 communicating the port 25 and the head-side pressure chamber 24 with the oil. A through hole 26 is formed.

The groove 32 opens directly into the port 25,
The oil through hole 26 has an orifice 31 and both ends open to the groove 32 and the head side pressure chamber 24. Since the inner diameter of the port 33a of the guide 33 is smaller than the inner diameter of the port 25, the cushion ring 28 is attached to the port 33a of the guide 33.
, A gap is formed between the outer periphery of the tip of the cushion ring 28 and the inner periphery of the port 25, whereby the groove 32 is always open in the port 25.

Further, the orifice 31 is located outside the inner periphery of the port 25 and opens to the groove 32. Therefore, the oil passing through the orifice 31 hits the opposing wall surface of the groove 32,
The flow velocity will be reduced. That is, the pressure difference is reduced by reducing the flow velocity after passing through the orifice 31,
It is possible to prevent generation of abnormal noise caused by rapid expansion of fine bubbles in oil. Further, since the oil through hole 26 is formed between the groove 32 on the inner peripheral side of the port 25 and the head side pressure chamber 24, the length of the oil through hole 26 can be shortened, and the drilling is facilitated. .

According to the embodiment shown in FIG. 1, the cushion ring 28 enters the port 33a of the guide 33 near the maximum extension, and the tip of the cushion ring 28 penetrates the guide 33 and enters the port 25 at the maximum extension. I do. At this time, the high-pressure hydraulic oil in the head-side pressure chamber 24 flows out to the port 25 through the oil passage 26, the orifice 31 and the groove 32, and a part of the oil flows into the inner circumference of the port 33 a of the guide 33 and the outer circumference of the cushion ring 28 And the flow resistance between the gap and the orifice 31 acts as a cushion to prevent the piston 22 from decelerating and suddenly colliding with the cylinder head 21, in other words, the end face of the fitting portion 30. Is done.

FIG. 2 shows another embodiment of the present invention.
In this configuration, an oil through hole 26 having an orifice 31 is formed at the end of the fitting portion 30 on the pressure chamber side in an oblique direction, and the port 25 communicates with the head side pressure chamber 24 through the oil through hole 26. It was done. This embodiment is different from the embodiment of FIG. 1 in that the groove 32 is not provided. In this case, the oil after passing through the orifice 31 is applied to the outer surface of the piston rod 23 or the cushion ring 28. As a result, the flow velocity is reduced, preventing the expansion of fine bubbles in the oil, and preventing the generation of abnormal noise. Other structures, functions and effects are shown in FIG.
Is the same as

FIG. 3 shows another embodiment of the present invention.
This is a V-shaped groove in which the groove 32 is formed in a ring shape and the cross section is formed in a V-shape. Other structures are the same as those in FIG.

FIG. 4 shows another embodiment of the present invention.
This is one in which the groove 32 is formed in a ring shape and the cross section is formed in a U-shape.

FIGS. 5A and 5B relate to another embodiment of the present invention, in which one or more grooves 32 are formed at arbitrary intervals, and the cross-sectional shape is rectangular. For example, it is formed in a U-shape. However, the cross-sectional shape need not be the one shown in the figure.

FIG. 6 also relates to another embodiment of the present invention, in which a groove 32 is formed in an annular shape, a cross-sectional shape is made rectangular, and an oil hole 26 is formed of a thin and long chalk. The choke itself does not have an orifice and produces flow resistance. 3 to 6 show the cross section of the cylinder head 21, other structures, functions and effects are the same as those of the embodiment of FIG.

FIG. 7 relates to another embodiment of the present invention.
This is provided with a cushion device on the cylinder bottom side. That is, in the hydraulic cylinder according to this embodiment, the cylinder head and the cylinder bottom 35 are connected to both ends of the cylinder tube 20, and the piston 22 fixed to the piston rod 23 via the nut 39 moves in the cylinder tube 20. The piston 22 is freely inserted into the cylinder tube 20, and the head side pressure chamber and the bottom side pressure chamber 36 are inserted into the cylinder tube 20.
The cylinder bottom 35 has a supply / discharge port 37 connected to a hydraulic pressure source and a port 38 communicating the supply / discharge port 37 with the bottom pressure chamber 36. The end of the piston rod 23 is provided with a projection 40 which fits into the port 38 in the vicinity of the most compression.

In the present invention, an annular guide 41 for fitting the projection 40 in the vicinity of the most compression is projected from the inner periphery of the pressure chamber side end of the port 38, and the annular guide 41 is provided at the pressure chamber side end of the cylinder bottom 35. An oil passage hole 42 and a groove 43 formed of a chalk for communicating the bottom pressure chamber 36 and the port 38 are formed so as to bypass the port 41 a of the guide 41.

In the above case, the oil through hole 42 may be a through hole having an orifice as in FIG. 1, or the oil through hole 42 may be formed obliquely without the groove 43 as in FIG. Then, the oil that has passed through the oil through hole 42 may hit the outer surface of the protrusion 40 to reduce the flow velocity.

The groove 43 may be an annular groove as shown in FIGS. 3 to 6, one or more adjacent grooves, and may have a rectangular or U-shaped cross section.

In the embodiment shown in FIG. 7, the projection 40 enters the port 38 at the time of the most compression, and makes the cushion by the flow resistance effective. That is, when the protrusion 40 enters the port 41 a of the guide 41, the inner periphery of the port 41 a and the protrusion 40
The high-pressure hydraulic oil in the bottom-side pressure chamber 36 flows out to the port 38 through a gap between the outer periphery of the oil reservoir and the oil through hole 42, and the cushion is made effective by the flow resistance of the gap and the oil through hole 42. As described above, the oil that has passed through the oil through hole 42 hits the wall surface of the groove 43, and the flow velocity is reduced, so that the expansion of bubbles in the oil is suppressed, and the generation of abnormal noise can be prevented. Other operations and effects are substantially the same as those in FIG.

[0038]

According to the present invention, the following effects can be obtained.

According to the first to sixth aspects of the present invention, an annular guide is formed in the inner periphery of the port, and a groove near the supply / discharge port is formed from the guide, and this groove is connected to the cylinder head side pressure chamber or the bottom side pressure chamber. Is provided, the pressure oil in the cylinder head side pressure chamber or the bottom side pressure chamber is ejected to the port side through the oil through hole and the groove at the time of the most extension or near the most compression, At this time, the pressure oil hits the wall surface of the groove, and the flow velocity is reduced, so that there is no rapid expansion of fine bubbles in the oil, thereby preventing generation of abnormal noise.

According to the seventh to tenth aspects of the present invention, an annular guide is projected from the inner periphery of the port, and the cylinder head side pressure chamber or Since the bottom-side pressure chamber is connected to the port, the pressure oil in the cylinder head-side pressure chamber or the cylinder bottom-side pressure chamber is ejected to the port side through the oil through hole when near the maximum expansion or near the maximum compression. The pressurized oil hits the outer surface of the piston rod, the outer surface of the cushion ring, or the outer surface of the protrusion, and the flow velocity is reduced, so that there is no rapid expansion of fine bubbles in the oil, thereby preventing generation of abnormal noise.

Further, according to the invention of each claim, the oil through hole is formed between the pressure chamber and the port, so that the oil through hole can be formed to be short, thereby facilitating drilling of the oil through hole. Thus, breakage of a drill for drilling holes can be prevented.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of a fluid pressure cylinder according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of a fluid pressure cylinder according to another embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of a fluid pressure cylinder according to another embodiment of the present invention.

FIG. 4 is a partially enlarged sectional view of a fluid pressure cylinder according to another embodiment of the present invention.

FIG. 5A is a partially enlarged sectional view of a fluid pressure cylinder according to another embodiment of the present invention. (B) It is an expanded sectional view of a slot.

FIG. 6 is a partially enlarged sectional view of a fluid pressure cylinder according to another embodiment of the present invention.

FIG. 7 is a partially enlarged sectional view of a fluid pressure cylinder according to another embodiment of the present invention.

FIG. 8 is a partially enlarged sectional view of a conventional hydraulic cylinder.

[Explanation of symbols]

 Reference Signs List 20 Cylinder tube 21 Cylinder head 22 Piston 23 Piston rod 24 Head side pressure chamber 25, 38 Port 26, 42 Oil through hole 28 Cushion ring 33 Guide 35 Cylinder bottom 36 Bottom side pressure chamber 37 Supply / discharge port 39 Cushion member 40 Projection 41 guide

Claims (10)

[Claims] 1. A cylinder head and a cylinder bottom are connected to both ends of a cylinder tube, and a piston rod is movably inserted into the cylinder tube via a piston. The cylinder head is formed with a supply / discharge port connected to a hydraulic pressure source and a port connecting the supply / discharge port to the pressure chamber on the head side. In a fluid pressure cylinder provided with a cushion ring that fits into the cylinder, an annular guide is protruded on the inner periphery of the port, and a groove is formed near the supply / discharge port from the guide, and the cylinder side has a head side. A fluid pressure cylinder, wherein an oil passage hole communicating the pressure chamber and the groove is formed. 2. A cylinder head and a cylinder bottom are connected to both ends of a cylinder tube, and a piston rod is movably inserted into the cylinder tube via a piston. A pressure supply / discharge port connected to a hydraulic pressure source and a port connecting the supply / discharge port to the bottom side pressure chamber are formed at the bottom of the cylinder. In a fluid pressure cylinder having a projection fitted to a port, an annular guide is protruded on the inner periphery of the port, and a groove is formed near the supply / discharge port from the guide. A fluid pressure cylinder, wherein an oil through hole communicating the side pressure chamber and the groove is formed. 3. The hydraulic cylinder according to claim 1, wherein the oil passage is formed in a horizontal direction or an oblique direction and has an orifice in the middle. 4. The fluid pressure cylinder according to claim 1, wherein the oil passage is formed of a choke formed in a horizontal direction or an oblique direction. 5. The hydraulic cylinder according to claim 1, wherein the groove is one annular groove or a plurality of spaced grooves. 6. The fluid pressure cylinder according to claim 1, wherein the inner periphery of the groove is formed in a rectangular, V-shaped or U-shaped cross section. 7. A cylinder head and a cylinder bottom are connected to both ends of a cylinder tube, and a piston rod is movably inserted into the cylinder tube via a piston. The cylinder head is formed with a supply / discharge port connected to a hydraulic pressure source and a port connecting the supply / discharge port to the pressure chamber on the head side. In a fluid pressure cylinder provided with a cushion ring that fits into a port, an annular guide is protrudingly provided on the inner periphery of the port, and an oblique oil that communicates the head side pressure chamber and the port with the cylinder head. A fluid pressure cylinder characterized in that a through hole is formed so as to bypass said guide inner port. 8. A cylinder head and a cylinder bottom are connected to both ends of a cylinder tube, and a piston rod is movably inserted into the cylinder tube via a piston. A pressure supply / discharge port connected to a hydraulic pressure source and a port connecting the supply / discharge port to the bottom side pressure chamber are formed at the bottom of the cylinder. In a fluid pressure cylinder having a projection fitted to a port, an annular guide is protrudingly provided on the inner periphery of the port, and an oblique direction connecting the bottom side pressure chamber and the port to a cylinder bottom is provided. A hydraulic cylinder wherein an oil passage is formed so as to bypass the guide inner port. 9. The hydraulic cylinder according to claim 7, wherein the oil passage has an orifice in the middle. 10. The hydraulic cylinder according to claim 7, wherein the oil passage is formed of a chalk.