WO2006089515A1

WO2006089515A1 - Feed valve comprising a counter-nut

Info

Publication number: WO2006089515A1
Application number: PCT/DE2006/000268
Authority: WO
Inventors: Steffen Löbach
Original assignee: Bosch Rexroth Ag
Priority date: 2005-02-22
Filing date: 2006-02-15
Publication date: 2006-08-31
Also published as: DE102005008202A1

Abstract

Disclosed is a feed valve, particularly for a hydraulic press, comprising a valve cone (40) whose valve shaft (44) is screwed together with a guide bush (90) on which a closing spring (84) rests that is used for biasing the valve cone counter to a valve seat (38), a connection from a first working connection (A) to a second working connection (B) being opened and closed in a controlled manner via said valve seat (38). The valve shaft is provided with two threaded sections (92, 104) which are threaded in opposite directions. A first threaded section is associated with the guide bush while a second threaded section is assigned to a counter-nut (106) via which the guide bush is connected in a torsion-proof manner to the valve shaft.

Description

description

Filling valve with locknut

The invention relates to a filling valve according to the preamble of patent claim 1.

Filling valves are essentially hydraulic pilot operated check valves, which are used, for example, in hydraulic presses to bring a plunger of a pressing cylinder at high speed in working or rest position.

In rapid traverse, the plunger of the press cylinder is extended at a high operating speed, whereby the pressure in the pressure chamber decreases. In order to avoid damage to the pressing cylinder, this pressure chamber is to be filled with pressure medium in as short a time as possible. This is done via the arranged in a pressure line between a tank and the pressing cylinder filling valve, which opens by the resulting negative pressure in the pressing cylinder, so that pressure medium can be sucked from the tank. After completion of the pressing operation, the plunger is quickly brought to its rest position, wherein the previously filled in rapid traverse pressure chamber must be emptied. For this purpose, the filling valve is acted upon by a control pressure, so that it opens against the flow direction and the pressure medium from the decreasing pressure chamber can flow back into the tank.

Examples of such filling valves are in the

Data sheets RD 20 478 and RD 20 485 from Bosch

Rexroth described. The known, shown in Figure 1, filling valve 1 has a valve housing 2 with two

Working connections A, B and a control connection X. In the valve housing 2 is a valve cone 4 for up and

Controlling a pressure medium connection between the

Working connections A, B arranged so that, for example, pressure fluid from a tank (not shown, working port A) in a press cylinder

(not shown, working port B) can be sucked without pressure. Via a pressure port P which opens into the working port B, a pressure build-up in the pressing cylinder is possible by means of a pump, not shown. In the basic position of the valve cone 4 is biased by a closing spring 6 against a valve seat 8. The closing spring 6 is supported on a radial shoulder 10 of a receiving space 12 and engages a contact shoulder 14 of a guide sleeve 16, which is attached via a arranged in an annular groove 20 securing ring 18 on the valve stem 22.

When prefilling the press cylinder in rapid traverse of the valve cone 4 is lifted due to the sinking pressure in the press cylinder of the valve seat 8, so that quickly pressure medium can flow from the tank. To empty the pressing cylinder, the valve cone 4 is lifted against the flow direction of the pressure medium by the valve seat 8 via a control pressure applied to the control port X, which acts on a control piston 24 and via this on the valve cone 4, so that now the pressure medium flow back into the tank can. After emptying the pressing cylinder, the control piston 24 is depressurized and moved by a strong compression spring 26 in its rest position. The filling valve 1 is back in the normal position.

A disadvantage of the known solutions that, in particular with short cycle times between the valve stem and the guide sleeve loads can occur, leading to a fracture of the locking ring and thus lead to repairs and downtime of the hydraulic press.

In order to improve the mechanical load capacity, a filling valve is disclosed in EP 1 039 146 A1, in which the guide sleeve is screwed to the valve stem and counteracted via a radially inserted securing pin

Loosening is secured. Although this solution has an improved mechanical strength of the guide sleeve / valve stem connection, but requires a complex multi-part construction of the valve housing to the

To allow mounting of the safety pin.

In contrast, the present invention seeks to provide a filling valve, which allows over conventional solutions improved life with a simplified construction of the valve housing.

This object is achieved by a filling valve having the features of patent claim 1.

The filling valve according to the invention has a valve cone whose valve stem is screwed to a guide sleeve, on which a closing spring for biasing the valve cone is supported against a valve seat. According to the invention, the valve stem has two threaded sections whose thread direction is different, a first threaded section of the guide sleeve and a second threaded section being associated with a lock nut via which the guide sleeve is connected in a rotationally fixed manner to the valve stem. The lock nut according to the invention allows a reliable anti-rotation of the compound and due to the axial introduction of a simplified assembly in the valve housing. As a result, in comparison with the prior art according to EP 1 039 146 A1, a multi-part housing structure can be used - A -

be waived. Due to the different thread direction of lock nut and guide sleeve unintentional release of the guide sleeve is effectively prevented because a rotational movement of the guide sleeve in the opening direction causes a rotational movement of the lock nut in the closing direction and this practically tightened.

According to a preferred embodiment, the second threaded portion disposed on the valve stem is radially recessed to permit mounting of the guide sleeve on the first threaded portion.

Preferably, the first threaded portion has a right-hand thread and the second threaded portion has a left-hand thread. As a result, when the guide sleeve is loosened, i. in a left turn, the lock nut also turned to the left and this practically tightened due to their left-hand thread. This prevents the connection from loosening.

The lock nut is preferably non-rotatably connected via an axially introduced backup and positively connected to the guide sleeve.

According to a preferred embodiment of the invention, the fuse is a locking pin. This can be carried out with full or hollow cross-section and is introduced axially into the lock nut / guide sleeve connection to form a form-locking Losdrehsicherung. As a result, unintentional loosening of the lock nut is prevented.

At the lock nut and the guide sleeve, a plurality of bores are preferably formed, which can be brought into overlap so that they form a common receptacle for the backup. Preferably, the number of holes in the

Locknut and the • guide sleeve different.

As a result, in the assembly of the lock nut on the second threaded portion already at a rotation of the

Lock nut by an angle which is smaller than the pitch of the holes, a ^' bore of the lock nut are brought into coincidence with a bore of the guide sleeve, so that a common receptacle for securing arises.

The holes in the lock nut are preferably through holes. In a preferred embodiment, eight through-holes are arranged in the lock nut.

In a further embodiment of the invention, the bores of the guide sleeve are formed as blind bores and arranged on an end face of an end portion of the guide sleeve. Preferably, in the

Guide sleeve formed nine blind holes.

to the AC load, and ^thus' improving the fatigue strength of the screw connection between the guide bush and the valve stem, the valve stem is preferably at least partially formed in the region of the guide sleeve as a reduced shank.

It has proved to be particularly advantageous to bring the guide sleeve over an end face with a contact shoulder of the valve stem in abutment.

Other advantageous developments of the invention are the subject of the other dependent claims. In the following, a preferred embodiment of the invention is explained in more detail with reference to schematic drawings. Show it:

Figure 1 is an axial section of a known filling valve (prior art);

Figure 2 shows an inventive filling valve in an axial section;

Figure 3 is an enlarged view of the detail Y of Figure 2;

Figure 4 is a detail view of the guide sleeve of Figure 3;

Figure 5 is a plan view of the guide sleeve of Figure 4;

Figure β is a plan view of the lock nut of Figure 3 and

Figure 7 is a plan view of the bolted to the valve stem and secured by the lock nut guide sleeve.

FIG. 2 shows a filling valve 28 designed in an intermediate plate construction with a substantially disc-shaped valve housing 32, which merges at a rear end face 34 into an approximately hub-shaped housing projection 36. In the valve housing 32 with respect to a valve seat 38 axially displaceable poppet 40 for opening and controlling a pressure medium connection between a first and a second working port A, B is arranged. The valve cone 40 has an approximately disk-shaped valve plate 42 with a in the housing projection 36 extending central valve stem 44 and is axially guided over this in a central guide bore 46 of the valve housing 32. An end portion 48 of the valve stem 44 passes through the guide bore 46 of the valve housing 32 into a receiving space 50 into which the end face radially widened and axially bounded by a screwed into the housing projection 36 screw plug 52. The receiving space 50 is connected via an axially parallel pressure equalization bore 54 with a limited of the valve plate 42 and the valve housing 32 back annulus 56.

The working port A is connected to a tank, not shown, and the working port B to a cylinder space of a press piston (not shown). In the valve housing 32 a connected to a pressure port P radial pressure bore 58 is formed, which opens via a pressure chamber 60 in the working port B, so that via a pump, not shown, a pressure build-up in the pressing cylinder is made possible.

In the housing projection 36, a coaxially extending control channel 62 is formed, which is connected via a radial control bore 64 to a control port X and via a connecting channel 66 in a control chamber 68 opens, so that the back of a displaceable in the receiving space 50 and the control chamber 68 limiting cup-like control piston 72 with a

Control pressure can be applied to lift the valve plate 42 from the valve seat 38, whereby the filling valve 28 is unlocked and thus pressure medium in the reverse direction via the working port B to the working port A, that can flow from the cylinder chamber of a press piston to the tank. The control piston 72 is connected via a compression spring 74 biased, which is supported on an annular space 76 delimiting the receiving space 50 and acts on an opposite, inner end face 78 of the control piston 72. The working port A is connected to two semi-annular channels 82, which open into an annular space 56 (for reasons of clarity, only part of the channels 82 is indicated in dashed line in FIG. 2). The working port B of the filling valve 28 is practically formed by the free flow cross-section of the valve seat 38 with the valve disc 42 lifted.

In the illustrated basic position of the valve plate 42 is biased by a closing spring 84 against the valve seat 38, so that no pressure medium between the working ports A, B can flow. The closing spring 84 is supported on a radial shoulder 86 of the receiving space 50 and acts on a contact shoulder 88 of a guide sleeve 90. The closing spring 84 has a lower spring rate than the compression spring 74.

As can be seen in particular from FIG. 3, which shows an enlarged view of the detail Y of FIG. 2, the guide sleeve 90 is screwed to the end section 48 of the valve stem 44 via a first threaded section 92. In order to achieve the required tightening torque of the screw connection between the guide sleeve 90 and the valve stem 44, the end portion 48 of the valve stem 44 is recessed stepwise radially and forms a contact shoulder 94, to which an end face 96 of the guide sleeve 90 can be brought into abutment. To improve the interchangeability and fatigue strength of the valve stem 44 is formed in a portion 98 encompassed by the guide sleeve 90 sections as a strain shaft 100 with radially reset diameter d. Around To avoid voltage peaks at the transitions between the expansion shaft 100 and the valve stem 44, these are provided with transition radii R.

According to the invention, a second threaded section 104 separated from the first threaded section 92 by a recess 102 is formed at the end section 48 of the valve shaft 44 with a thread direction opposite to the first threaded section 92. On the second threaded portion 104, a lock nut 106 is screwed, via which the guide sleeve 90 is rotatably connected to the valve stem 44. In the embodiment shown, the first threaded portion 92 is designed as a right-hand thread and the second threaded portion 104 as a left-hand thread and with respect to the first threaded portion 92 radially set back to allow the mounting of the guide sleeve 90 on the valve stem 44. In an alternative variant of the valve stem 44 is made in two parts, wherein the two sections are screwed on at least one screw or a piece is screwed as a mushroom-shaped screw in an internal thread of the valve stem to the assembly of the guide sleeve 90 on the valve stem 44 without a radial offset the threaded portions 92, 104 to allow. The lock nut 106 according to the invention allows a reliable anti-rotation of the compound and due to the axial insertion on the second threaded portion 104 a simple installation in the valve housing 32. This can be dispensed with over the prior art according to EP 1 039 146 Al on a multi-part housing structure. Due to the different thread direction of lock nut 106 and guide sleeve 90 inadvertent release of the guide sleeve 90 is effectively prevented, since a rotational movement of the guide sleeve 90 in the opening direction causes a rotational movement of the lock nut 106 in its closing direction and this practically tightened.

The lock nut 106 is rotatably connected via an axially introduced locking pin 108 and positively connected to the guide sleeve 90. This prevents unintentional loosening of the lock nut 106 during operation of the filling valve 28. For this purpose, on the guide sleeve 90 and the lock nut 106 a plurality of holes 112; 118 formed, of which two can be brought into overlap, so that they form a common receptacle 114 for the locking pin 108. The non-rotatable and positive locking means of the locking pin 108 allows a reliable anti-rotation lock the lock nut 106 and due to the axial introduction (in Figure 3 from above) easy installation in the valve housing 32nd

According to FIG. 4, which shows an individual representation of the guide sleeve 90 from FIG. 3, it essentially has a cylindrical base body 116, which is penetrated by a stepped through-bore 118. On an inner peripheral surface 120 of the through-bore 118, a thread 124 is formed in a bush-shaped end portion 122 of the guide sleeve 90 for screwing to the first threaded portion 92 of the valve stem 44 (see FIG. 3). As can be seen in particular from FIG. 5, nine axially arranged blind bores 112, which form a common pitch circle 128, are introduced on an end face 126 of the end section 122 designed as a tool hexagon. The tool hexagon 122 facilitates the screwing of the guide sleeve 90 onto the valve stem 44 and is provided with a peripheral chamfer 130 on the front side. As can be seen in particular from FIG. 6, which shows a plan view of the lock nut 106 from FIG. 3, this is made with a tool hex 132 and has a centrally arranged threaded bore 134. Via the threaded bore 134, the lock nut 106 can be screwed to the second threaded portion 104 of the valve stem 44 (see FIG. 3). In an end face 136 of the lock nut 106 open eight coaxially arranged through holes 118 which lie on a common pitch circle 138. The tool hex 132 facilitates the screwing of the lock nut 106 on the second threaded portion 104 of the valve stem 44 and is provided on both sides with a circumferential chamfer 140.

According to FIG. 7, which shows a plan view of the guide sleeve 90 screwed to the valve stem 44 and secured by the lock nut 106, one of the eight through bores 118 of the lock nut 106 can be brought into overlap with one of the nine blind bores 112 (indicated by dashed lines) of the guide sleeve 90 in that they together form a receptacle 114 for the securing pin 108. Since the number of holes 112, 118 in the lock nut 106 and the guide sleeve 90 is different, during assembly, ie the screwing of the lock nut 106 on the second threaded portion 104 of the valve stem 44 already at a rotation of the lock nut 106 by an angle, the is smaller than a pitch T of the holes, each one of the through holes 118 of the lock nut 106 with one of the blind holes 112 of the guide sleeve 90 are brought into coincidence, so that the common receptacle 114 is formed for the locking pin 108. In this case, the usually applied tightening torque is sufficient to turn the lock nut 106 in such a way that two bores are brought into coincidence can be. In the embodiment shown with eight through holes of the lock nut 106, the pitch T is 360 ° / 8 = 45 °. Since nine blind bores 112 are formed on the guide sleeve 90, the maximum angular distance necessary for covering one of the bores 112 is 45 ° / 9 = 5 °.

As an alternative to this embodiment, the guide sleeve 90 may be executed without the holes 112 and the lock nut 106 with a single end-side axial bore. In this variant, a blind hole is drilled in the guide sleeve after screwing the guide sleeve 90 and the lock nut 106 on the valve stem 44 via the axial bore in the lock nut. The common bore formed by the axial bore of the lock nut and the blind bore in the guide sleeve serves, as already explained, for receiving the axially inserted securing pin 108.

In the following, the function of the filling valve 28 will be explained by way of example with reference to FIGS. 2 and 3. To empty a pressing cylinder, the valve cone 40 is lifted off the valve seat 38 by means of the control pressure. For this purpose, the back of the control piston 72 is acted upon by a sufficient control pressure, the control piston 72 moves against the biasing force of the strong compression spring 74 away from the screw 52 and takes after a predetermined stroke by running its inner end face 78 on the end face of the axially over the lock nut 106th protruding end portion 48 of the valve stem 44, the valve plug 40 with. After running the control piston 72 on the end portion 48 of the valve stem 44, in addition to the biasing force of the compression spring 74, the biasing force of the closing spring 84 counteracts Control pressure. The valve cone 40 lifts off due to the applied control pressure from the valve seat 38 and is a pressure medium connection between the working ports Ä, B free. As a result, pressure medium can flow from a pressure cylinder connected to the working port B to the tank connected to the working port A (not shown). As soon as the control pressure is lowered, the springs 74, 84 relax and bring the poppet 40 back into abutment with the valve seat 38, so that the pressure medium connection between the working ports A, B is interrupted. When prefilling the pressing cylinder, the valve cone 40 lifts off by the resulting negative pressure during rapid traverse in the pressing cylinder. As a result, pressure medium can be sucked from the tank via the working port A and the working port B into the cylinder space of the pressing cylinder.

Disclosed is a filling valve 28, in particular for a hydraulic press, with a valve plug 40 whose valve stem 44 is screwed to a guide sleeve 90, on which a closing spring 84 is supported for biasing the valve plug 40 against a valve seat 38, via which a connection between a first working port A to a second working port B on or is zuusteuerbar. According to the valve stem 44 has two threaded portions 92, 104 with opposite thread direction, wherein a first threaded portion 92 of the guide sleeve 90 and a second threaded portion 104 is associated with a lock nut 106 through which the guide sleeve 90 is rotatably connected to the valve stem 44. LIST OF REFERENCE NUMBERS

1 filling valve

2 valve body 4 valve cone

6 closing spring

8 valve seat

10 radial shoulder

12 Sewing chamber 14 Plant shoulder

16 guide sleeve

18 circlip

20 ring groove

22 Valve stem 24 spool

26 compression spring

28 filling valve

30 guide sleeve

32 valve housing 34 end face

36 housing projection

38 valve seat

40 poppets

42 valve plate 44 valve stem

46 guide bore

48 end section

50 recording room

52 Plug screw 54 Pressure equalization hole

56 annulus

58 pressure hole

60 pressure chamber

62 control channel 64 control bore

66 connection channel 68 control room

70 inner wall

72 control piston

74 compression spring 78 end face

80 face 82 channel

84 closing spring

86 Radial shoulder 88 Abutment shoulder

90 guide sleeve

92 first threaded section

94 contact shoulder

96 face 98 area

100 sprain stem

102 puncture

104 second threaded portion

106 Lock nut 108 Locking pin

110 through hole

112 blind hole

114 recording

116 main body 118 through hole

120 inner circumferential surface

122 end section

124 thread

126 face 128 pitch circle

130 chamfer

132 Tool hex

134 threaded hole

136 face 138 pitch circle

140 chamfer

Claims

claims

1. filling valve, in particular for a hydraulic press, with a valve cone (40) whose

Valve stem (44) is screwed to a guide sleeve (90) on which a closing spring (84) for biasing the valve plug (40) against a valve seat (38) is supported, via which a connection between a first working port (A) to a second Working port (B) is auf- or zuueruerbar, characterized in that the valve stem (44) has two threaded portions (92, 104) whose thread direction is different, wherein a first threaded portion (92) of the

Guide sleeve (90) and a second threaded portion

(104) is associated with a lock nut (106), via which the guide sleeve (90) rotationally fixed to the

Valve stem (44) is connected.

2. Filling valve according to claim 1, wherein the second arranged on the valve stem threaded portion (104) is radially recessed.

3. Filling valve according to claim 1 or 2, wherein the first threaded portion (92) has a right-hand thread and the second threaded portion (104) has a left-hand thread.

4. Filling valve according to one of the preceding claims, wherein the lock nut (106) via an axially introduced fuse (108) rotatably and positively connected to the guide sleeve (90).

5. Filling valve according to claim 4, wherein the fuse (108) is a locking pin.

6. filling valve according to claim 4 or 5, wherein at the lock nut (106) and the guide sleeve (90) has a

A plurality of bore (112, 118) are formed, which can be brought into registry so that they form a common receptacle (114) for the fuse (108).

7. Filling valve according to claim 6, wherein the number of bores (112, 118) in the lock nut (106) and the guide sleeve (90) is different.

8. Filling valve according to claim 6 or 7, wherein the bores (118) in the lock nut (106) are through holes.

9. filling valve according to claim 8, wherein the lock nut eight through holes (118).

10. Filling valve according to claim 6, wherein the bores (112) of the guide sleeve (90) formed as blind bores and on an end face (126) of an end portion (122) of the guide sleeve (90) are arranged.

11. Filling valve according to claim 10, wherein in the guide sleeve (90) nine blind holes (112) are formed.

12. Filling valve according to one of the preceding claims, wherein the valve stem (44) in the region of the guide sleeve (90) is at least partially formed as a expansion shaft (100).

13. Filling valve according to one of the preceding claims, wherein the guide sleeve (90) via an end face (96) with a contact shoulder (94) of the valve stem (44) can be brought into abutment.