JPH07197910A - Hydraulic cylinder - Google Patents

Abstract

PURPOSE:To provide a hydraulic cylinder where drive of a piston is started simultaneously with pressure propagation by opening a passage for supplying or discharging an oil pressure into a cylinder to a piston abutting surface, and forming grooves for introducing the oil pressure to be supplied or discharged from the supply/discharge passage. CONSTITUTION:In an end member 3, a supply/discharge passage 4 communicated with a second supply/discharge port 13 for supplying or discharging an oil pressure to or from a cylinder 1 is opened to a piston abutting surface 3a. In a piston 2, an oil pressure introducing-in groove 6 is formed at an end surface 2a facing to the piston abutting surface 3a of the end member 3. Consequently, the oil pressure to be supplied or discharged from the supply/discharge passage 4 to the cylinder 1 is introduced between the piston 2 and the end member 3 via the oil pressure introducing-in grooves 5, 6, to be thus dispersed in the radial and circumferential directions of the end surface 2a of the piston. As a result, an area where the oil pressure acts on the piston 2 is increased at the beginning of drive of the piston 2, thereby enhancing a drive speed in the arrow B direction of the piston 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a hydraulic cylinder for operating an arm or the like of a shovel excavator.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional hydraulic cylinder includes a cylinder 1 into which hydraulic pressure is supplied and discharged, and a piston 9 which is reciprocally driven by the hydraulic pressure supplied to and discharged from the cylinder 1.
And an end member 10 having a piston contact surface 10a for closing the end opening of the cylinder 1 and limiting the drive range of the piston 9.

The cylinder 1 has a first supply / discharge port 11 for supplying / discharging hydraulic pressure therein, and an insertion hole 1a for inserting a pin or the like at the rear end thereof. Further, the piston 9 is
A screw hole (not shown) is formed in the center of the facing end surface 9a located on the side opposite to the first supply / discharge port 11, and one end of the advancing / retreating rod 12 that advances and retracts toward the tip end side of the cylinder 1 is formed in the screw hole. It is concluded. The advancing / retreating rod 12 has a plug member 17 on the peripheral surface near one end.
Is fixed, and an insertion hole 12a for inserting a pin or the like is provided at the other end of the cylinder 1 which always projects toward the tip end side.

The end member 10 is a second member for supplying and discharging hydraulic oil.
The supply / discharge port 13 and the supply / discharge passage 4 opening to the piston contact surface 10a are formed, and the insertion hole 14 for inserting the advancing / retreating rod 12 with a gap is formed in the central portion. The end member 10
A recess 16 is formed near the opening of the supply / discharge passage 4.
A sealing material 15 for slidingly contacting the outer periphery of the advancing / retreating rod 12 to seal the inside of the cylinder 1 on the inner peripheral surface of the insertion hole 14 on the tip side of the second supply / discharge port 13 of the end member 10. Is provided.

By operating a control valve (not shown) connected to the first and second supply / discharge ports 11 and 13, hydraulic pressure is supplied from the first supply / discharge port 11 into the cylinder 1. When the hydraulic pressure can be discharged from the cylinder 1 through the gap between the insertion hole 14 and the outer peripheral surface of the advancing / retreating rod 12 and the supply / discharge passage 4 and the second supply / discharge port 13, the piston 9 moves in the direction of arrow A.
6, the opposing end surface 9a of the piston 9 abuts the piston contact surface 10a of the end member 10, as shown in FIG.
At the same time, the plug member 17 closes the gap between the insertion hole 14 and the outer peripheral surface of the advancing / retreating rod 12. On the contrary, the second of the end member 10
When the hydraulic pressure is supplied from the supply / discharge port 13 to the cylinder 1 and the hydraulic pressure can be discharged from the first supply / discharge port 11 of the cylinder 1, the piston 9 is driven in the arrow B direction.

[0006]

In the conventional hydraulic cylinder, when the piston 9 is moved in the direction of the arrow B from the state shown in FIG. 6, the piston 9 is supplied from the second supply / discharge port 13 at the beginning of driving. The hydraulic pressure acted only on the facing end surface 9a of the piston 9 corresponding to the recess 16 formed near the opening of the supply / discharge passage 4. Therefore, even if the pressure is propagated to the piston 9, there is a problem that the driving force for driving the piston 9 is relatively small and the start of driving the piston 9 is delayed.

An object of the present invention is to provide a hydraulic cylinder in which the piston starts to drive at the same time as the pressure is propagated.

[0008]

According to another aspect of the present invention, there is provided a hydraulic cylinder in which a supply / discharge passage for supplying / discharging hydraulic pressure to / from the cylinder is opened at a piston contact surface of an end member, and the end surface of the piston facing the end member is provided. At least one of the piston contact surfaces of the end member is formed with a hydraulic pressure introducing groove for introducing the hydraulic pressure supplied and discharged from the supply / discharge passage along the opposed end surface of the piston and the piston contact surface of the end member.

In the hydraulic cylinder of the second aspect, the hydraulic pressure introducing groove is formed in a circular shape.

In the hydraulic cylinder according to claim 3, the hydraulic pressure introducing groove is formed in a spiral shape.

In the hydraulic cylinder according to the fourth aspect, the hydraulic pressure introducing groove is formed along the radial direction.

In the hydraulic cylinder according to a fifth aspect of the present invention, the hydraulic pressure introducing groove is formed by curving in an arc shape.

[0013]

According to the hydraulic cylinder of the present invention, the supply / discharge passage for supplying / discharging the hydraulic pressure to / from the cylinder is opened at the piston contact surface of the end member, and the end surface of the piston facing the end member and the piston contact surface of the end member are provided. Since at least one side is formed with a hydraulic pressure introducing groove for introducing the hydraulic pressure supplied and discharged from the supply / discharge passage along the opposing end surface of the piston and the piston contact surface of the end member, the hydraulic pressure supplied into the cylinder is supplied to the piston. The acting area can be relatively increased, and the driving speed in the initial stage of driving can be improved. At this time, since only the hydraulic pressure introducing groove is formed, the areas of the opposed end surface and the piston contact surface are not reduced, and therefore, deformation and damage are less likely to occur even if collision or pressing is repeated.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A hydraulic cylinder according to an embodiment of the present invention will be described. The same configurations as those of the conventional example are denoted by the same reference numerals and description thereof is omitted.

That is, as shown in FIG. 1, the hydraulic cylinder according to this embodiment has a cylinder 1 into which hydraulic pressure is supplied and discharged, and an arrow A, which indicates the hydraulic pressure supplied to and discharged from the cylinder 1.
The piston 2 is reciprocally driven in the B direction, and the end member 3 has a piston contact surface 3a that closes the end opening of the cylinder 1 and restricts the drive range of the piston 2.

The end member 3 has a supply / discharge passage 4 provided in communication with a second supply / discharge port 13 for supplying / discharging hydraulic pressure into / from the cylinder 1, and opens at the piston contact surface 3a. The piston 2 has a hydraulic pressure introducing groove 6 formed on an end surface 2a facing the piston contact surface 3a of the end member 4, and a ring-shaped sealing material 2b provided on the peripheral surface so as to be in sliding contact with the inner peripheral surface of the cylinder 1. There is. As shown in FIG. 2, each of the hydraulic pressure introducing grooves 6 is a circular narrow groove provided on a concentric circle and communicates with the hydraulic introducing groove 5 which is a narrow groove radially extending in the radial direction of the piston 2. ing.

According to the hydraulic cylinder configured as described above, the hydraulic pressure supplied to and discharged from the supply / discharge passage 4 into the cylinder 1 is supplied to the hydraulic guide groove while the piston 2 is in contact with the piston contact surface 3a of the end member 3. It can be introduced between the piston 2 and the end member 3 via 5 and 6, and can be dispersed in the radial direction and the circumferential direction of the opposed end surface 2a of the piston. Therefore, the area where the hydraulic pressure acts on the piston 2 in the initial stage of driving the piston 2 increases, and the driving speed of the stone 2 in the direction of arrow B can be improved.

Moreover, even if the hydraulic pressure introducing grooves 5 and 6 are provided, the area of the opposed end surface 2a of the piston 2 is not significantly reduced, so that the opposed end surface 2a of the piston 2 and the piston contact surface 3a of the end member 3 are strongly pressed. Even if the piston 2 is hit or collided, the piston 2 is not deformed or damaged, and has excellent durability.

Further, as shown in FIG. 3, when a hydraulic pressure introducing groove 7 is formed which is curved and extends in an arc shape in the radial direction of the opposed end surface 2a of the piston, the hydraulic pressure introducing groove 7 can be easily formed by using a lathe. Since it can be formed and processed, for example, the piston 2
The screw holes for connecting the advancing / retreating rod 12 can be simultaneously formed in the step of lathe processing, whereby the number of manufacturing steps can be reduced and the productivity can be improved. Further, in the case where the spiral hydraulic pressure introducing groove 8 extending over the entire circumference of the facing end surface 2a as shown in FIG. 4 is formed instead of the hydraulic pressure introducing groove 6, the area where the hydraulic pressure acts on the facing end surface 2a of the piston 2 is formed. Can be further increased.

In the embodiment, the hydraulic pressure introducing groove 5,
6, 7 and 8 are formed on the opposed end surface 2a of the piston 2,
These may be formed on the piston contact surface 3a of the end member 3 or both of them. Furthermore, each of the hydraulic pressure introducing grooves 5, 6, 7, and 8 described above may be formed alone or in combination, but in any case, the supply / discharge passage 4 is formed by these hydraulic pressure introducing grooves 5. , 6, 7, or 8 is desirable. Further, it is desirable that the respective grooves are formed in good balance on the whole of the opposed end surface 2a and the piston contact surface 3a.

[0021]

According to the hydraulic cylinder of the present invention, since the hydraulic pressure supplied to and discharged from the supply / discharge passage into the cylinder can be introduced between the piston and the end member through the hydraulic pressure introduction groove, the strength of the piston contact surface of the end member can be increased. It is possible to relatively widen the area where the hydraulic pressure acts on the piston without damaging the piston. Therefore, the driving speed in the initial stage of driving the piston can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a hydraulic cylinder according to an embodiment of the present invention.

FIG. 2 is a schematic view showing the shape of a hydraulic pressure introducing groove of the hydraulic cylinder according to the embodiment of the present invention.

FIG. 3 is a schematic view showing the shape of a modified example of the hydraulic pressure introducing groove of the hydraulic cylinder according to the embodiment of the present invention.

FIG. 4 is a schematic view showing the shape of another modification of the hydraulic pressure introducing groove of the hydraulic cylinder according to the embodiment of the present invention.

FIG. 5 is an overall view of a conventional hydraulic cylinder.

FIG. 6 is a sectional view showing a main part of a conventional hydraulic cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 2a Opposing end face 3 End member 3a Piston contact face 4 Supply / discharge passage 5 Hydraulic pressure introducing groove

Claims (5)

[Claims] 1. A cylinder into which hydraulic pressure is supplied and discharged, a piston which is reciprocally driven by the hydraulic pressure supplied and discharged into the cylinder, an end opening of the cylinder is closed, and an end face restricts a drive range of the piston. A hydraulic cylinder having an end member that serves as a piston contact surface, and a supply / discharge passage that supplies and discharges hydraulic pressure to / from the cylinder is opened in the piston contact surface of the end member, and faces the end member of the piston. At least one of the end surface and the piston contact surface of the end member is formed with a hydraulic pressure introduction groove for introducing the hydraulic pressure supplied and discharged from the supply / discharge passage along the opposing end surface of the piston and the piston contact surface of the end member. A hydraulic cylinder that is characterized. 2. The hydraulic cylinder according to claim 1, wherein the hydraulic pressure introducing groove is formed in a circular shape. 3. The hydraulic cylinder according to claim 1, wherein the hydraulic pressure introducing groove is formed in a spiral shape. 4. The hydraulic cylinder according to claim 1, wherein the hydraulic pressure introducing groove is formed along a radial direction of the piston. 5. The hydraulic cylinder according to claim 4, wherein the hydraulic pressure introducing groove is formed by curving in an arc shape.