DOUBLE-ACTING OVERFLOW VALVE OF A WORKING CYLINDER AND MASTER CYLINDER

Abstract

A double-acting overflow valve of a working cylinder includes a housing with an encompassing wall and a first and a second axial delimiting wall disposed opposite one another. A first valve body has a first valve tappet with a conical shape and passes through the first axial bore to define a first annular gap with a gap width that is dependent on a position of the first valve body along an actuation path thereof. A second valve body has a second valve tappet with a conical shape and passes through the second axial bore to a second annular gap with a gap width that is dependent on a position of the second valve body along an actuation path thereof. A first and second counter bearing are provided. A first actuating element defines a maximum actuation path of the first valve body by acting on the first counter bearing. A second actuating element defines a maximum actuation path of the second valve body by acting on the second counter bearing. A first spring applies an axial force to the first valve body in a direction of the closed position of the first valve disk. A second spring applies an axial force to the second valve body in a direction of the closed position of the second valve disk.

Claims

1-5. (canceled).

6. A double-acting overflow valve of a working cylinder, comprising: a housing having an encompassing wall and a first delimiting wall and a second axial delimiting wall being arranged opposite one another, said encompassing wall and said delimiting walls defining an interior, said first axial delimiting wall having a first axial bore and defining a first annular valve bearing surface surrounding said first axial bore on an inner side of said first axial delimiting wall, and said second axial delimiting wall having a second axial bore and defining a second annular valve bearing surface surrounding said second axial bore on an inner side of said second axial delimiting wall; a first valve body and a second valve body; said first valve body having a first valve tappet, a first valve disk and a first actuation path limiter, said first valve tappet having a first valve tappet head and a first valve tappet foot; said first valve tappet resting on said first valve disk with said first valve tappet foot, said first valve tappet having a conical shape and passing through said first axial bore, and in an open position said first valve tappet and said first axial bore defining a first annular gap therebetween, a gap width of said first annular gap being dependent on a position of said first valve body along an actuation path thereof; said first valve disk having a first axial annular surface surrounding said first valve tappet foot, said first axial annular surface and said first annular valve bearing surface defining a sealing plane in a closed position of said first valve disk, said first actuation path limiter resting on said first valve disk, said first valve tappet and said first actuation path limiter being arranged axially opposite each another; said second valve body having a second valve tappet, a second valve disk and a second actuation path limiter, said second valve tappet having a second valve tappet head and a second valve tappet foot; said second valve tappet resting on said second valve disk with said second valve tappet foot, said second valve tappet having a conical shape and passing through said second axial bore and, in an open position, said second valve tappet and said second axial bore defining a second annular gap therebetween, a gap width of said second annular gap being dependent on a position of said second valve body along an actuation path thereof; said second valve disk having a second axial annular surface surrounding said second valve tappet foot, said second axial annular surface and said second annular valve bearing surface defining a sealing plane in a closed position of said second valve disk, said second actuation path limiter resting on said second valve disk, said second valve tappet and said second actuation path limiter being arranged axially opposite each another; a first counter bearing and a second counter bearing; said first actuation path limiter having a first actuating element and said first actuating element defining a maximum actuation path of said first valve body by acting on said first counter bearing; said second actuation path limiter having a second actuating element, and said second actuating element defining a maximum actuation path of said second valve body by acting on said second counter bearing; a first spring and a second spring, said first spring applying an axial force to said first valve body in a direction of said closed position of said first valve disk and said second spring applying an axial force to said second valve body in a direction of said closed position of said second valve disk.

7. The double-acting overflow valve of a working cylinder according to claim 6, wherein said first or second actuating element is constructed as an exchangeable bush.

8. The double-acting overflow valve of a working cylinder according to claim 6, wherein said first or second actuating element is constructed as an axially adjustable threaded bush.

9. The double-acting overflow valve of a working cylinder according to according to claim 6, wherein said first or second valve tappet has a progressively conical shape starting from said first or second valve tappet foot.

10. A master cylinder, comprising: a cylinder unit with closure parts and a piston unit, said piston unit defining a first and a second working chamber; said piston unit having a double-acting overflow valve according to claims 6 connecting said first and said second working chamber to one another.

Description

[0052] The invention is explained as an exemplary embodiment in more detail by means of

[0053] FIG. 1 partially sectional view of the double-acting overflow valve

[0054] FIG. 2 partially sectional view of the master cylinder with a double-acting overflow valve.

[0055] FIG. 1 shows an embodiment of the double-acting overflow valve 10 in a partially sectional view.

[0056] The overflow valve 10 has a housing 20, a first and a second valve body 30; 40, a first and a second counter bearing 50; 60 as well as a first and a second spring element 70; 80.

[0057] The housing 20 consists of an encompassing wall 21 and two axial delimiting walls 22; 23 positioned opposite one another, wherein in the embodiment the encompassing wall 21 is detachably connected to each of the delimiting walls 22; 23 by means of a pair of threads 24. Thus, an interior 25 is formed which is divided in two by a partition wall in the selected embodiment. The two sections of the interior 25 are connected by a duct 92, which passes through the partition wall so that a continuous flow of the fluid is made possible.

[0058] The two axial delimiting walls 22; 23 each have an axial bore 26; 28 and on the inside each form an annular valve bearing surface 27; 29 surrounding the axial bore.

[0059] In this embodiment, the first valve element 30 is designed in one piece and can be divided into a first valve tappet 31, a first valve disk 32 and a first actuation path limiter 33. The first valve tappet 31 has a first valve tappet head 34 and a first valve tappet foot 35 and passes through the first axial bore 26. According to the invention, the first valve tappet 31 is conical, wherein the diameter of the valve tappet 31 increases in the direction of the valve tappet foot 35.

[0060] In the open position, which can be assumed by an axial displacement of the first valve element 30 in the direction of the inner surface of the overflow valve 10, a first annular gap 36 is formed between the first valve tappet 31 and the first axial bore 26, the gap width of which is variable due to the conical shape of the first valve element 30 and is dependent on an actuation path of the first valve element 30.

[0061] The first valve disk 32 has a radial extension relative to the first valve tappet 31 so that a first axial annular surface is formed around the first valve tappet foot 35, and comes, in a closed position, into contact with the first annular valve bearing surface 27 and thereby forms a sealing plane. In addition, a sealing 90 is provided in the area of the first valve disk 32, which in the closed position is pressed against the first annular valve bearing surface 27 by the axial force of the first spring element 70 thus ensuring the seal.

[0062] The first actuation path limiter 33 is arranged on the first valve disk 32 axially opposite the first valve tappet 31 and has a first actuating element 38. A contact of the first actuating element 38 to the first counter bearing 50, which is formed by the diametrical connecting web of the encompassing wall 21 here, defines a maximum actuation path of the first valve element 30 according to the invention.

[0063] In the present case, the first actuating element 38 is designed as a thread bush, with the thread bush being provided with an internal thread and screwed onto a pin having an external thread. The adjustment of different maximum actuation paths and thus the width of the first annular gap 36 is then carried out via the screw-in depth of the thread bush.

[0064] In a modified exemplary embodiment, it is intended to design the first actuating element 38 as an exchangeable bush the axial length of which can be used for setting different maximum actuation paths. Depending on the desired overflow volume per time unit, it can be replaced by other exchangeable bushes of other axial lengths.

[0065] The previous explanations on the design and components of the first valve element 30 also apply to the second valve element 40 in this exemplary embodiment.

[0066] In order to apply an axial force to the first valve element 30 in the direction of the closed position, a first spring element 70 is provided. A corresponding second spring element 80 is provided for the second valve element 40. In the event of a pressure failure, the overflow valve 10 can be closed on both sides and a seal against the inflowing or outflowing fluid can be provided thanks to the axial resetting force. In the exemplary embodiment, the spring elements 70; 80 are designed as compression springs made of steel.

[0067] FIG. 2 shows a partially sectional view of a master cylinder 100 in the piston unit 120 of which a double-acting overflow valve 10 is installed according to the exemplary embodiment as shown in FIG. 1.

[0068] The master cylinder 10 is intended to be used in particular in a master-slave cylinder arrangement. It comprises a cylinder unit 110 with a bottom closure part 111 and a guide closure part 112 as well as a piston unit 120 consisting of a piston and a piston rod. The piston unit 120 forms a first working chamber 121 on the piston side and a second working chamber 122 on the piston rod side. Due to the fluid flow, the two working chambers 121; 122 are connected by the overflow valve 10.

[0069] A slave working cylinder (not shown here) can be connected with its piston side to a main connection 131 on the piston rod side via a supply line. According to the invention, the leakage losses occurring at the slave working cylinder can then be compensated by the overflow valve 10 installed in the piston unit 120 of the master cylinder 100. This compensation takes place when the adaptation part 140 acts on the inner wall of the guide closure part 112, which corresponds to a fully extended piston rod.

[0070] The piston rod side of the overflow valve 10 can thus be actuated by a mechanical force.

[0071] The operating pressure is applied via a main connection 130 on the piston side, and the piston side of the overflow valve 10 is opened via the prevailing hydraulic operating pressure. If the adaptation part 140 acts on the inner wall of the guide closure part 112, an open position of the piston rod side of the overflow valve 10 is provided by pressing in the valve tappet (in FIG. 2 without reference numeral) so that the fluid flowed in on the piston side can then flow out via the main connection 131 on the piston rod side into a working chamber of the slave working cylinder.

LIST OF REFERENCE NUMERALS

[0072] 10 Overflow valve

[0073] 20 Housing

[0074] 21 Encompassing wall

[0075] 22 First delimiting wall

[0076] 23 Second delimiting wall

[0077] 24 Thread pair

[0078] 25 Interior

[0079] 26 First axial bore

[0080] 27 First annular valve bearing surface

[0081] 28 Second axial bore

[0082] 29 Second annular valve bearing surface

[0083] 30 First valve element

[0084] 31 First valve tappet

[0085] 32 First valve disk

[0086] 33 First actuation path limiter

[0087] 34 First valve tappet head

[0088] 35 First valve tappet foot

[0089] 36 First annular gap

[0090] 37 First axial annular surface

[0091] 38 First actuating element

[0092] 40 Second valve element

[0093] 41 Second valve tappet

[0094] 42 Second valve disk

[0095] 43 Second actuation path limiter

[0096] 44 Second valve tappet head

[0097] 45 Second valve tappet foot

[0098] 46 Second annular gap

[0099] 47 Second axial annular surface

[0100] 48 Second actuating element

[0101] 50 First counter bearing

[0102] 60 Second counter bearing

[0103] 70 First spring element

[0104] 80 Second spring element

[0105] 90 Sealing of the first valve disk

[0106] 91 Sealing of the second valve disk

[0107] 92 Duct

[0108] 100 Master cylinder

[0109] 110 Cylinder unit

[0110] 111 Bottom closure part

[0111] 112 Guide closure part

[0112] 120 Piston unit

[0113] 121 First working chamber

[0114] 122 Second working chamber

[0115] 130 Main connection on the piston side

[0116] 131 Main connection on the piston rod side

[0117] 140 Adaption part