JPH0221007A - Hydraulic cylinder - Google Patents

Abstract

PURPOSE:To improve durability of a hydraulic cylinder by forming an oil supply port consisting of a main port and sub ports and providing the sub ports near by the main port. CONSTITUTION:An expansion side port 5 and a contraction side port 6 are formed by a main port 7 and a plurality of sub ports 8, and the sub ports 8 are provided near by the main port 7. Accordingly, the concentration of stress near by the contraction side port 5 and the expansion side port 6 can be dispersed so that strength durability against the lengthwise crack of a cylinder tube 1 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hydraulic cylinder, and more particularly to an improvement in a refueling port coupled to a cylinder cylinder.

(Prior Art) Conventionally, as shown in FIG.
The screws 1 and 2 are movably inserted into the cylinder 1, and the screw 1 and the hem 2 divide the cylinder 1 into two lower oil chambers. It is known that each of them is connected to a hydraulic power source through an extension port 6 connected to the tube 4.

In such a hydraulic cylinder, when pressure oil is supplied into the compression side chamber A through the compression side port 5, the hydraulic oil from the expansion side chamber B is discharged to the outside through the expansion side port 6. The hydraulic cylinder becomes retracted.

On the other hand, contrary to the above, when pressure oil is supplied into the expansion side chamber B through the expansion side port 6, the hydraulic oil from the compression side chamber A is discharged to the outside through the compression side port 5, and the hydraulic cylinder becomes extended.

[Invention or problem to be solved].

However, in the conventional hydraulic cylinder described above, a tangential stress (hoop stress) F is generated in the cylinder tube 4 due to the cylinder internal pressure, and the stress F is applied to the cylinder tube 4 as shown by the arrow in FIG. Concentration of stress F occurs around the oil supply port 5.6 provided in the oil supply port 5.6, and a tangential stress F that is approximately three times as large as that of the smooth portion is generated.

As a result, as shown in Fig. 4, a vertical crack X occurs in the cylinder tube 4 around the oil supply port 5.6 on the cylinder tube 4, resulting in an inconvenience in which oil gushes out and the cylinder loses its function as a hydraulic cylinder. There is some consideration.

Therefore, the present invention can reduce the concentration of stress near the oil supply port connected to the cylinder tube, and improve the strength and durability of the cylinder tube against vertical cracking.
The purpose of the present invention is to provide a new hydraulic cylinder that does not cause oil gushing or the like.

(Means for solving problems) To achieve the above object, the present invention has a configuration.

The oil supply port connected to the cylinder tube of the cylinder is formed from a main port and a sub-port, and the sub-port is provided near the main port.

(Function) The oil supply port is formed from a main port and a sub-port, and since the sub-port is provided near the main port, hydraulic oil is supplied and discharged through the main port and sub-port. This means that stress concentration near the port can be dispersed.

(Embodiments) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 to 3, in the hydraulic cylinder according to the present invention, a piston rod 3 is movably inserted into the cylinder 1 via a piston 2, and the piston 2 has an overwhelm chamber A and an expansion chamber in the cylinder 1. It is separated from side room B.

Further, a pressure side port 5 and a growth side port 6, which are oil supply ports, are connected to the cylinder tube 4 of the cylinder 1 by welding or the like, and the pressure side chamber A is connected to a hydraulic pressure source (not shown) via the pressure side port 5.

The growth side chamber B is connected to a hydraulic power source (not shown) via the growth side port 6.

Port 5.6 has main port 7 and multiple sub ports 8,
8, and the sub-port 8.8 is provided near the main port 7 in the tangential direction.

In such a hydraulic cylinder, when pressure oil is supplied from the hydraulic source into the compression side chamber A through the main port 7 and sub ports 8, 8 of the compression side port 5, one hydraulic oil is supplied to the expansion side port 6.
The hydraulic cylinder is discharged to the outside through the main port 7 and sub-ports 8, 8, and the hydraulic cylinder is in a contracted state.

On the other hand, contrary to the above, when pressure oil is supplied from the hydraulic source into the expansion side chamber B via the main port 7 and sub ports 8, 8 of the expansion side port 6, hydraulic oil from the overwhelming chamber A is supplied to the compression side port. 5
is discharged to the outside through the main port 7 and sub ports 8, 8, and the hydraulic cylinder 8 becomes in an extended state.

Therefore, supply and discharge of pressure oil during the expansion and contraction operation of the cylinder is performed via the main port 7 and sub ports 8, 8 of the compression side port 5, and the main port 7 and sub ports 8, 8 of the expansion side port 6, respectively. As shown in Figure 3, the concentration of stress F near the oil supply port can be dispersed, and the strength and durability against vertical cracking of the cylinder tube 4 can be improved.
This will help prevent oil from blowing out.

In the above embodiment, the sub-ports 8, 8 are provided near the main port 7.

Of course, the main port and sub-port of the oil supply port may be integrally molded to disperse stress concentration.

(Effect of the invention) Book 9. According to the invention, since the hydraulic oil is supplied and discharged through the oil supply port which is provided as a sub-port near the main port, stress concentration near the oil supply port can be dispersed.

This has the advantage that it is possible to improve the strength and durability against vertical cracking of the cylinder tube due to stress concentration, and to prevent oil from blowing out.

Further, according to the present invention, the strength and durability of the cylinder tube is improved by providing the sub-port near the main port, so there is an advantage that the wall thickness of the cylinder tube can be kept the same. .

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional front view of a hydraulic cylinder according to a preferred embodiment of the present invention, FIG. 2 is a partial cross-sectional view of the hydraulic cylinder,
Fig. 3 is a partially enlarged plan view showing the state of stress applied to the hydraulic cylinder, Fig. 4 is a longitudinal sectional front view of a conventional hydraulic cylinder, and Fig. 5 is a partially enlarged plan view showing the state of stress applied to the conventional hydraulic cylinder. FIG. 1...Cylinder 2...Piston 3...Piston rod 4...Cylinder tube 5.6...Oil supply port 7...Main port 8...Sub port A...Pressure side chamber B...・Naka concubine room Figure 4

Claims (3)

[Claims] (1) A piston rod is movably inserted into the cylinder via a piston, and the piston divides the cylinder into two oil chambers, upper and lower, and each oil chamber is connected to a hydraulic pressure source through an oil supply port connected to the cylinder tube. 1. A hydraulic cylinder connected to a hydraulic cylinder, wherein a refueling port is formed of a main port and a sub-port, and the sub-port is provided near the main port. (2) The hydraulic cylinder according to claim 1, wherein the sub-port is provided in the vicinity of the main port in a tangential direction. (3) The hydraulic cylinder according to claim 1, wherein the subport is formed from a plurality of holes.