Hydraulic pressure amplifier

Abstract

A hydraulic pressure amplifier with a housing which has an end face at a low pressure side and an end face at a high pressure side and a circumferential wall between the two end faces, wherein an outlet valve is arranged adjacent the end face on the high pressure side, and an outlet duct for the hydraulic liquid which is under high pressure. In a pressure amplifier of the above-described type, the outlet duct opens into the circumferential wall or extends through a connection plug which is screwed into the end face on the high pressure side and closes off an assembly duct which receives the outlet valve.

Description

BRIEF DESCRIPTION OF THE DRAWING

In the drawing:

FIG. 1 is a schematic illustration of a hydraulic pressure amplifier;

FIG. 2 is a side view of the hydraulic pressure amplifier;

FIG. 3 is an end view of the low pressure side;

FIG. 4 is an end view of the high pressure side; and

FIG. 5 is a schematic view showing an embodiment which is modified as compared to FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A pressure amplifier 1 for hydraulic liquid schematically illustrated in FIG. 1 is connected through a switching valve 2 to a pressure source 3, for example, a pump, and to a tank 4. The switching valve is connected to a low pressure side 5 which has a low pressure inlet 6 and a low pressure outlet 7.

The low pressure inlet 6 is connected to an amplifier 8 which usually is constructed as a stepped piston. The amplifier 8 is connected through an outlet valve 9 to a high pressure outlet 10 which, in turn, is connected to a schematically illustrated user 11.

In the illustrated embodiment, the pressure amplifier 1 additionally includes a discharge valve 12 which can be regulated through the low pressure outlet 7, and a control valve 13 constructed as a check valve, as is known in the art.

The functional elements of the pressure amplifier 1, i.e., the amplifier 8, the outlet valve 9, the discharge valve 12 and the control valve 13, are accommodated in a housing 14 which has a lower part 15, a middle part 16 and an upper part 17, as illustrated in FIG. 2. FIG. 2 merely is a schematic illustration and is not to be understood as being on scale. The lower part 15 has an end face 18 on a low pressure side and the upper part 17 has an end face 19 on a high pressure side. the housing 14 is otherwise essentially cylindrical.

Arranged in the end face 18 on the low pressure side are the low pressure inlet 6 and the low pressure outlet 7. Additionally extending through the lower part 15 are threaded bolts 20, 21 which hold the lower part 15, the middle part 16 and the upper part 17 together in the axial direction.

Arranged in the upper part 17 is the outlet valve 9 which is placed in an assembly duct 22 which is closed off by a closing plug 23. As illustrated in FIG. 1, the outlet valve 9 is constructed as a check valve. The valve has a relatively large diameter of, for example, 10 mm. The assembly duct 22 also requires an appropriately large diameter.

The high pressure outlet 10, on the other hand, should have a significantly smaller diameter of, for example, 2 or 3 mm. Consequently, the high pressure outlet 10 extends to the circumferential wall through a high pressure duct 26 which branches off from the assembly duct 22. The upper part 17 has a flattened portion 24 in the area of the high pressure outlet 10. The high pressure outlet 10 has a diameter expansion 25 into which can be placed a high pressure fitting, not illustrated in detail.

It can be seen that the high pressure outlet 10 opens into the circumferential wall of the upper part 17 at a distance from the end face 19 on the high pressure side which is greater than the distance of the end of the outlet valve 9 from this end face 19 on the high pressure side. In this case, the high pressure outlet 10 could be connected, for example, to the assembly duct 22 through an inclined bore. However, the outlet valve 9 can also end at the same distance from the end face 19 on the high pressure side where the high pressure outlet 10 also opens into the circumferential surface of the housing 4.

As illustrated in broken lines, the upper part 17 may additionally have a second flattened portion 24a into which opens a second high pressure outlet 10a which is connected to the assembly duct 22 through a second high pressure duct 26a.

All parts which move within the housing, i.e., the valve elements of outlet valve 9, outlet valve 12 and control valve 13 as well as the stepped piston of the amplifier 8 move in the same direction, namely in the longitudinal or axial direction of the housing 14.

The high pressure outlets 10, 10a which are not required at a given time can be closed in a simple manner by closing plugs, not illustrated.

The closing plug 23 may also have an adaptor for a pressure sensor 17 or the pressure sensor 27 itself. This makes it possible to monitor the operation of the pressure amplifier 1, particularly with respect to the desired or required pressure build-up.

FIG. 5 shows an embodiment which is modified compared to the embodiment of FIG. 2. FIG. 5 shows the embodiment partially in a sectional view, wherein the same and equivalent elements are provided with the same reference numerals as in FIGS. 1 through 4.

In the embodiment of FIG. 5, a connecting plug 27 is screwed into the end face 19 on the high pressure side. The connecting plug protrudes with a section 28 from the upper part 27 of the housing 14.

The connecting plug 27 has a diameter which is greater than the diameter of the outlet valve 9 and, thus, also of the assembly duct 22 in which the outlet valve 9 is arranged.

In this manner, it is possible to have the connecting plug 27 with its inner end face 29 rest against a sealing surface 20 of the housing 14, or more specifically the upper part 17, which surrounds the assembly duct 22. In order to improve the sealing effect, an O-ring 31 is arranged in the inner end face 29 of the connecting plug 27, wherein the O-ring ensures the improved sealing action.

The high pressure duct 26 which forms the outlet duct extends through the connecting plug 27. The high pressure duct has the diameter expansion 25 which is provided with an internal thread 32, so that a high pressure fitting can be screwed in.

The high pressure duct 26 has a conical connection geometry 33 into which the high pressure fitting can be placed with a corresponding conical counter surface. The high pressure fitting has, in a conventional but not illustrated manner, a high pressure duct whose diameter corresponds approximately to that of the high pressure duct 26.

Provided at the inner end of the diameter expansion 25 is a relief duct 34 which opens toward the circumferential surface of the connecting plug 27. Provided at this location on the housing is an annular duct 35 which is in communication through a relief opening 36 in the end face 19 with the ambient surroundings. In the case of a small leakage, the relief duct 34, the annular duct 35 and the relief opening 36 prevent an unduly high pressure from acting on the pair of threads with the internal thread 32 and a corresponding external thread at the high pressure fitting.

Consequently, the alternative embodiment of FIG. 5 also requires relatively little structural space. The embodiment only needs three principal components of the housing, wherein the connecting plug 27 has two purposes. On the one hand, the connecting plug 27 closes off the assembly duct 22 for the outlet valve 9. On the other hand, the plug 27 serves as means for keeping the diameter of the high pressure duct 25 small and simultaneously for making available a connecting geometry for the high pressure fitting.

While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

1. A hydraulic pressure amplifier comprising a housing having an end face on a low pressure side and an end face on a high pressure side and a circumferential wall between the end faces, an outlet valve arranged adjacent the end face on the high pressures side, and an outlet duct for hydraulic liquid which is under high pressure, wherein the outlet duct opens into the circumferential wall or extends through a connecting plug screwed into the end face on the high pressure side and closing off an assembly duct in which the outlet valve is received.

2. The pressure amplifier according to claim 1, wherein the outlet duct is branched off from the assembly duct which extends from the end face on the high pressure side, wherein the outlet valve is arranged in the assembly duct and wherein the assembly duct is closed by a closing plug.

3. The pressure amplifier according to claim 2, wherein the closing plug comprises an adapter for a pressure sensor.

4. The pressure amplifier according to claim 1, wherein the outlet duct has in an area of an outer end thereof a diameter expansion.

5. The pressure amplifier according to claim 4, wherein a relief path branches off in an area of an inner end of the diameter expansion.

6. The pressure amplifier according to claim 1, wherein the outlet valve is a check valve having a valve element which is movable in a direction perpendicularly of the end face.

7. The pressure amplifier according to claim 1, wherein the housing has a lower part on the low pressure side, an upper part on the high pressure side and a middle part between the lower and upper parts.

8. The pressure amplifier according to claim 7, wherein at least one of the components lower part, middle part and upper part is cylindrical.

9. The pressure amplifier according to claim 1, wherein the outlet duct opens into the circumferential wall at a distance from the end face on the high pressure side which is greater than a distance of the outlet valve from this end face.

10. The pressure amplifier according to claim 1, comprising a plurality of outlet ducts distributed in a circumferential direction and opening into the circumferential wall.

11. The pressure amplifier according to claim 1, wherein the housing has a flattened portion in an area of the opening of the outlet duct.

12. The pressure amplifier according to claim 1, wherein the connecting plug has a diameter which is greater than that of the outlet valve, and wherein the connecting plug rests with an inner end face thereof against a sealing surface of the housing.