DE19860466C1 - Pneumatically operated hydraulic pump has cylinder housing, integral valve base, end cap and control housing all injection moulded from plastics and with slide shoe moved by piston to inject work air and expel exhaust air - Google Patents

Abstract

The cylinder housing has an integral moulded valve base (3). The cylinder housing (2), the end cap (11) detachably associated with same and the control housing for the control piston as well as the slide shoe are all made of plastics such as polyoxymethylene. The pilot valves (4, 5) are provided in stepped bores (12, 13) of the valve base and the end cap (11). The control housing and piston (48) are provided at the side of the valve base (3). The control piston moves the slide shoe through which the work air is directed to the work chambers (34, 36) and the exhaust air is moved to the atmosphere (A).

Description

A pneumatically driven hydraulic pump in question standing type counts to the stand by DE 26 26 954 C2 of the technique. It has become diverse due to its Proven application in practice.

Such a hydraulic pump includes a significant one Version one back and forth in a cylinder housing air pistons that can be mounted and a non-positive ver bound hydraulic piston. This is via a suction valve with a suction line and via a pressure valve with a Pressure line connected. Because of the back and forth Movement of the air piston and thus also the hydraulics piston sucks in hydraulic fluid once and delivers this hydraulic medium then continues under pressure.

The reciprocating movement of the air piston will via a partly hollow spool and mind  least causes a pilot valve that be from the air piston is done and ensures that the spool from one is shifted to the other end position. The Piston spool has two different faces large effective areas. The smaller effective area is constant dig from the working air while the big one Effective area through the pilot valve with the working air is hit when the piston slide in the other Direction is shifted. For transferring the working air in the workrooms on both sides of the air piston and to Exhaust air discharge is the piston valve in one maneuverable stepped sleeve with cross holes and circumferential grooves and has several in Distance from each other circumferential sealing rings. In addition to the complicated sleeve, it forms in the known case a peculiarity that the sealing rings the mouths of the Boh stanchions in the sleeve constantly run over and thus one subject to considerable wear. The sleeve must also in the receiving bore of the hydraulic housing be stored sealed.

DE-PS 12 30 263 discloses a reversing arrangement for a Schubkol benmotor operated with gaseous pressure medium with a large number of individual parts. In a multi-channel housing that can be screwed onto the end cover of the air cylinder, a control piston can be moved back and forth between two channeled control housing covers 58 . In a circumferential recess of the control piston, a control slide is fitted, which is pressed by a spring against a channeled slide mirror plate, which is screwed tightly to the housing. In the control piston, two valve seats consisting of O-rings are provided, which are pressed by threaded plugs against a central spacer bush provided with transverse bores. A valve body designed as a ball is held in the spacer bushing and is lifted off the valve seats by the control pins penetrating the thread. The control pins are mounted in the end cover of the control housing.

The manufacture and assembly of this reversing arrangement is with a lot of effort and time. Here It should also be noted that usually a flare piston engine with such a reversing arrangement in several what sizes and types must be kept ready increased the effort even more.

The invention is based on the prior art DE 26 26 954 C2 the task of this hydraulic pump from the point of view of the series and modular system to be able to manufacture with less effort.

According to the invention, this object is achieved in the features of claim 1.

An important aspect here is that the Zy cover with the integral Ven tilboden, the end releasably assigned to the cylinder housing cap and also the reversing housing for the reversing piston and the slide shoe are now made of plastic, especially polyoxymethylene. These are preferred stands designed as injection molded parts. In this way is an inexpensive series production of all sizes and types guaranteed.

Furthermore, it is important that the sliding shoe the function of a flat slide was given. He depending on its position in the reversing housing, the Conduction of the working air in one or the other area Beitsraum on both sides of the air piston safely and over takes fer due to the trained recess in it  ner the transfer of the exhaust air from the work rooms in the atmosphere, especially through a silencer.

The sliding shoe is moved by an in Reversing housing arranged reversing piston with two un differently large frontal effective areas. The little ones nere effective area is always in the Umschaltge chamber house in which the glide shoe is located, and is permanently exposed to the working air. The order Control piston can be made of a light metal alloy be there. It is tightly guided in the reversing housing. The However, seals do not run over the mouth of a hole, so that they are therefore not particularly susceptible to wear det. The slide shoe is positively guided in the chamber, however, slides on an outside of the valve bottom. By flanging the reversing housing on the valve bottom is thus the operating position of the glide shoe ensured. Overall, the glide shoe runs over the mouths of three channels. These are in line one behind the other and extend across the movement direction of the air piston. The two outer channels are directly connected to the work rooms in the cylinder housing sen, while the middle channel, especially over a Silencer that leads to the atmosphere.

The non-positive and positive interaction of the reversal pistoning with the sliding shoe is particularly so advantageously promoted that of the rerouting chamber protruding housing, the small effective area on the front supporting length section of the reversing piston to the Adjusted length of the shoe and the shoe about has gripping circumferential recess. The exception Mung is particularly due to a turn on the reversal piston generated.  

According to claim 2, the chamber is via a branch channel in the Valve bottom constantly to the one that receives the 1st pilot valve Step hole connected. Depending on the position air piston ensures that either the large effective area of the reversing piston via the 1st pilot valve and the channels in the valve base and in the reversing area air is applied to the housing and the valve tappet of the 2nd pilot valve in the work space between the air piston and the end cap is reversed, or that the 1.Pilot valve with regard to its valve lifter in the Working space between the air piston and the valve base is pressed.

In this context, according to the characteristics of the Claim 3 the stepped bore in the valve bottom via channels in the valve bottom and in the reversing housing to one of the countries opposite section of the reversing piston with the large effective area guiding space in the reversing housing and via channels in the wall of the cylinder housing and in the end cap the step bore in the End cap connected. The larger effective area lies constantly in a room in the room that is tightly separated from the chamber Reversing housing. This room is above that in the valve bottom The first pilot valve provided can be supplied with working air and the 2nd pilot valve located in the end cap releasable into the atmosphere. Reversing piston and sliding shoes are not firmly connected to what the her position and assembly further simplified.

To the air from the room, from the stepped bore with the 2nd pilot valve and out of the channels between the 1st pilot valve, the room and the 2nd pilot valve NEN, according to claim 4, the stepped bore in the end cap directly into the atmosphere via a cross channel closed.  

The features of claim 5 see an embodiment with two coaxially arranged and with the Air pistons non-positively connected hydraulic pistons in front. To integrate the second hydraulic piston it is only necessary to correspond in the valve bottom appropriate guide hole. other changes are not required to have a double acting hydrau to provide lik pump.

According to the features of claim 6, he can hydraulic pump according to the invention but also with a hand activity. The air piston is over a Ge penetrating the valve bottom relatively movably rods against the restoring force of one in the work area between the air piston and the end cap Spring can be moved manually. So it just has to Spring inserted into the cylinder housing and the channel between the chamber and the Ar adjacent to the end cap be closed with a stopper. Wei No further changes are necessary. So can the hydraulic pump either with air or by hand be driven.

The features of claim 7 provide that a Ge rod associated hand lever is locked. To this  This way it can be ensured that when operating with If the hand lever does not move uncontrolled that can lead to injuries.

The invention is based on in the drawings gene illustrated embodiments explained in more detail. Show it;

Figure 1 in a schematic vertical longitudinal section of a pneumatically driven hydraulic pump.

FIG. 2 shows a side view of the hydraulic pump of FIG. 1 according to arrow II;

. Fig. 3 is a horizontal section through the view of Figure 2 along the line III-III;

Figure 4 is a section through the view of Figure 3 along the line IV-IV..;

Fig. 5 to 7, the illustrations of Figs 1, 3 and 4 in a different operational situation.

. Fig. 8 is a view corresponding to Fig 1 to that according to a further embodiment;

FIG. 9 shows a representation corresponding to that of FIG. 5 according to a further embodiment and

Fig. 10 shows the representation of Fig. 9 in a different operating position.

In Figs. 1, 2 and 5 is 1 with a pneumatically driven hydraulic pump referred to. The hydraulic pump 1 has a displaceable in a cylinder housing 2 made of plastic with integrally molded-on valve bottom 3 and in the two end positions pilot valves 4, 5 umsteuernden air piston 6, and a processor coupled to the air piston 6 frictionally hydraulic piston. 7 The Luftkol ben 6 has a circumferential groove 8 with a sealing ring 9 embedded therein, which comes to the sealing system on the inner wall 10 of the cylinder housing 2 .

At the valve base 3 facing away from the cylinder housing 2 , an end cap 11 made of plastic is releasably attached. The end cap 11 is slidably penetrated by the hydraulic piston 7 .

Both in the valve base 3 and in the end cap 11 be found in stepped bores 12 , 13, the pilot valves 4 and 5 , each having a valve tappet 14 and a valve head 15 Ven. In the middle length of the Ven tilstößel 14 sealing rings 16 are arranged. Further sealing rings 17 are located between the valve lifters 14 and the valve heads 15 . The pilot valves 4 , 5 are loaded by helical compression springs 18 in the direction of the air piston 6 . They are supported on bolts 19 , which are rotated into the spring spaces 20 of the stepped bores 12 , 13 .

In the valve bottom 3 , three transverse channels 21 , 22 , 23 are provided in a row one behind the other. All three transverse channels 21 , 22 , 23 open into an outer side 24 of the valve base 3 (see FIGS . 3 and 6), to which a reversing housing 25 made of plastic is also flanged, as can be seen in FIGS . 3 and 4. Of the three channels 21 , 22 , 23 , the middle channel 22 is connected via a channel 28 with a port 27 opening into the end face 26 of the valve base 3 , to which a muffler can be placed. Of the two other channels 21 , 23 , the channel 23 adjacent to the first pilot valve 4 is via a longitudinal channel 30 formed in the wall 29 of the cylinder housing 2 and channels 31-33 in the end cap 11 with the working space 34 for the air adjacent to the end cap 11 piston 6 connected. The third channel 21 in the valve base 3 is connected via a channel 35 to the valve chamber 3 neigh disclosed work space 36 .

Further, FIGS. 1 and 5 show that the valve tappet 14 leading length portion of bore 37 of the stages 12 in the valve bottom 3 via channels 39, 40, 41, 42 in the valve block 3, in the wall 29 of the cylinder housing 2 and in the end cap 11 is connected to the spring chamber 20 of the stepped bore 13 in the end cap 11 . In addition, the Ka channel 39 is connected via a further channel 43 in the valve base 3 and a channel 44 in the reversing housing 25 with a space 45 in the reversing housing 25 in which a length section 47 provided with a sealing ring 46 of a reversing piston 48 , which will be described in more detail below, can be displaced .

The lying between the length section 37 of the stepped bore 13 in the end cap 11 and the spring chamber 20 length section 38 is connected via a transverse channel 49 with the atmosphere A.

The reversing piston 48 is tightly guided in the reversing housing 25 on the one hand in the aforementioned space 45 and on the other hand in a bore 50 . For this purpose, a wide sealing ring 51 is embedded in a circumferential groove 52 of the reversing piston 48 . A provided with a recess 53 formed by a recess portion 54 of the reversing piston 48 protrudes into a chamber 55 of the reversing housing 25 . This chamber 55 is constantly connected to a source of working air AL (compressed air) via a connection 56 . The end 57 of the Umsteuerkol ben 48 in the chamber 55 has an end face surface 58 which is smaller than the effective surface 59 on the length portion 47 of the reversing piston 48 in the space 45 .

The length of the recess 53 on the reversing piston 48 corresponds to the length of a plastic, rectangularly configured sliding block 60 with a deflection recess 61 formed therein. This slide shoe 60 slides on the eye side 24 of the valve base 3 and runs over the mouths of the three channels 21 , 22 , 23 .

Still see Figs. 1, 4, 5 and 7 can be that the chamber 55 is connected via a branch channel 62 with the spring chamber 20 of the stepped bore 12 in the valve bottom 3.

The hydraulic piston 7 acts in a T-shaped channel 63 of a high-pressure housing 65 . This is on the one hand via a suction valve 64 with a suction line 66 for a hydraulic medium and on the other hand with a Druckven valve 67 in connection, which is connected to a pressure line 68 .

The operation of the hydraulic pump 1 emerging from FIGS . 1 to 7 is as follows:

Due to the design of the reversing housing 25 , drive air AL is always present in the chamber 55 via the connection 56 . Thus, the reversing piston is displaced 48 voltage level in the drawing to the left (Fig. 3 and 4), with 48 it is entrained by the force-locking and form-fitting coupling the Umsteu erkolbens with the sliding shoe 60 until the front end 69 of the chamber 55 it to Arrived in position. Working air AL can now pass from the chamber 55 via the channels 23 , 30 , 31 , 32 , 33 into the working space 34 adjacent to the end cap 11 . Because in this position of the sliding block 60 the working space 36 adjacent to the valve base 3 is connected to the atmosphere A via the channels 35 and 21 , the deflection trough 61 in the sliding block 60 and the channels 22 , 28 , the air piston 6 can move in the direction to the valve floor 3 . At the same time, working air AL is present from the chamber 55 via the branch duct 62 in the spring chamber 20 of the first pilot valve 4 , as a result of which its valve tappet 14 is displaced into the working chamber 36 according to FIG .

Shortly before reaching top dead center, the air piston 6 actuates the valve tappet 14 of the first pilot valve 4 and displaces it against the restoring force of the screw compression spring 18 to such an extent that the sealing ring 17 is lifted off the seat in the stepped bore 12 and in the branch channel 62 upcoming working air AL reaches the length section 38 of the stepped bore 12 in the channel 39 and via the channel 43 in the valve base 3 and the channel 44 in the reversing housing 25 in the length section 47 with the larger effective area 59 leading space 45 . At the same time, the working air AL is present via the channels 40 , 41 , 42 in the spring chamber 20 of the second pilot valve 5 . Whose Ven tilstößel 14 is thereby relocated to the end cap 11 neigh disclosed work space 34 .

Due to the facts that the active surface lying in the space 45 is greater than 59 the order to the control piston 48 in the chamber 55, the Umsteuerkol ben 48 together with the sliding shoe 60 in the direction of the on-circuit 56, moves as the active surface 58 for the working air AL to that the annular surface 70 comes to rest on the reversing piston 48 on the annular surface 71 of the reversing housing 25 ( FIGS. 6 and 7). By this shift, the connection between the connection 56 and the end cap 11 adjacent Ar beitsraum 34 is interrupted and this work space 34 via the channels 31 , 32 , 33 , 30 , 72 , 23 in the end cap 11 , in the wall 29 of the cylinder housing 2 and in the valve base 3 with the deflection trough 61 in the sliding block 60 and then via the channels 22 , 28 in the valve base 3 with the atmosphere sphere A connected.

The working air AL now passes through the channels 21 , 35 in the valve base 3 into the working space 36 adjacent to the valve base 3 and shifts the air piston 6 in the direction of the end cap 11 .

Because the valve lifter 14 of the first pilot valve 4 loses contact with the air piston 6 , the valve lifter 14 is displaced by the helical compression spring 18 into the position shown in FIG. 5. The sealing ring 17 is pressed onto its seat in the stepped bore 12 . The connec tion between the branch channel 62 and the adjacent to the Län gene section 38 in the stepped bore 12 in the valve bottom 3 channel 39 is interrupted. As a result, the air in the channels 39 , 40 , 41 , 42 , 43 and in the space 45 and in the spring space 20 of the second pilot valve 5 is enclosed.

Shortly before reaching the bottom dead center, the air piston 6 comes into contact with the valve tappet 14 of the second pilot valve 5 and lifts its sealing ring 17 from the sealing seat, so that the trapped air now intersects via the spring chamber 20 of the second pilot valve 5 and the Längenab 38 can stretch across the cross channel 49 into the atmosphere A.

Since thus the space 45 in the reversing housing 25 is connected to the atmosphere A, the working air AL now moves the reversing piston 48 and thus also the sliding block 60 back towards the space 45 and a further work cycle begins. Due to the Übersetzungsver 6 holds isses of the air piston to the hydraulic piston 7 sucks the hydraulic piston 7 in, so that then transferred to a direction of movement through the suction valve 64 the hydraulic medium from the suction line 66 in the other direction of movement the hydraulic medium under high pressure via the pressure valve 67 in the pressure line 68 becomes. Due to the oscillating movement of the air piston 6 and consequently the hydraulic piston 7 , an almost pulsation-free delivery flow is generated in the pressure line 68 .

Fig. 8 illustrates an embodiment of a pneumatically driven hydraulic pump 1 a, which corresponds in principle to that which was previously explained with reference to FIGS . 1 to 7. In addition, however, the hydraulic piston 7 in coaxial association, a further hydraulic piston 7 is associated with a. This further hydraulic piston 7 a is also non-positively connected to the air piston 6 and passes through the valve bottom 3 of the cylinder housing 2 sliding. The other hydraulic piston 7 a is effective like the first hydraulic piston 7 in a T-shaped channel 63 of a high-pressure housing 65 , in the sense that it sucks in hydraulic medium from the suction line 66 via a suction valve 64 and then under high pressure via a pressure valve 67 passes on to the pressure line 68 .

Since, as said, the embodiment of FIG. 8 otherwise corresponds to that of FIGS. 1 to 7, a further explanation of this type is omitted.

Also illustrated in FIGS. 9 and 10 exporting approximate shape of a hydraulic pump 1 b has in principle the design of the hydraulic pump 1 shown in FIGS. 1 to 7.

In addition, this type of manual operation is superimposed. The air piston 6 is via a Ven tilboden 3 relatively movable penetrating linkage 73 against the restoring force in the work space 34 between the air piston 6 and the end cap 11 th helical compression spring 74 manually displaceable. For this purpose, the channel 23 between the chamber 55 in the reversing housing 25 and the channels 30 , 31 , 32 , 33 leading to the working space 34 between the end cap 11 and the air piston 6 are closed.

The linkage 73 is provided with a hand lever 75 . By rotating the hand lever 75 about the longitudinal axis 76 of the hydraulic pump 1 b by 180 ° in each case, the linkage 73 is moved back and forth by the stroke of the air piston 6 in the cylinder housing 2 , so that hydraulic fluid 7, which is non-positively connected to the air piston 6, then also hydraulic medium can be sucked via a suction valve 64 from a suction line 66 and discharged via a pressure valve 67 into the pressure line 68 .

If the type shown in FIGS. 9 and 10 are operated pneumatically, the hand lever is locked in the recognizable from the Fig. 10 position 75. The channels 30 , 31 , 32 , 33 are always closed with the plug 77 . The suction stroke is always carried out by the spring 74 .

The lower piston chamber 34 is ventilated via a channel 78 . A suitable filter element 79 , which is pressed into the ventilation bore, prevents contamination of the lower piston chamber 34 .

During the pneumatic operation again, the hand lever 75 stands still and cannot cause any injuries.

Claims (7)

1. Pneumatically driven hydraulic pump ( 1 , 1 a, 1 b), which can be stored in a cylinder housing ( 2 ) made of plastic with an integrally formed valve base ( 3 ) and in the two end positions pilot valves ( 4 , 5 ) reversing air pistons ( 6 ) and one with the air piston ( 6 ) non-positively connected hydraulic likkolben ( 7 ), which is connected via a suction valve ( 64 ) with a suction line ( 66 ) and via a pressure valve ( 67 ) with a pressure line ( 68 ), and in which a 1st pilot valve ( 4 ) in a stepped bore ( 12 ) in the valve base ( 3 ) and the 2nd pilot valve ( 5 ) in a stepped bore ( 13 ) in a cylinder housing ( 2 ) which closes and the hydraulic piston ( 7 ) leading detachable end cap ( 11 ) are provided made of plastic, with a reversing housing ( 25 ) made of plastic being flanged releasably to the side of the valve base ( 3 ), in which a reversing piston ( 48 ) with two different-sized end-face effects Surfaces ( 58 , 59 ) with the help of a to a steering trough ( 61 ) having sliding shoe ( 60 ) through the working air (AL) can be moved back and forth, through which on the one hand in a guide shoe ( 60 ) leading chamber ( 55 ) in the reversing housing ( 25 ) constantly present working air (AL) in the valve base ( 3 ), in the wall ( 29 ) and in the end cap ( 11 ) of the cylinder housing ( 2 ) formed channels ( 21 , 22 and 23 , 30 , 31 , 32 , 33 ) alternately in one or the other of their working space ( 26 , 34 ) on both sides of the air piston ( 6 ) and on sealing bodies ( 17 ) of the pilot valves ( 4 , 5 ) and on the other hand the exhaust air from the working spaces ( 36 , 34 ) can be conducted into the atmosphere (A) via the deflection trough ( 61 ) in the sliding block ( 60 ), the length section ( 54 ) of the reversing piston protruding into the chamber ( 55 ) of the reversing housing ( 25 ) and bearing the smaller active surface ( 58 ) on the end face ( 48 ) to take the sliding shoe ( 60 ) one to the length e of the rectangularly configured sliding shoe ( 60 ) is adapted and has the circumferential recess ( 53 ) overlapping the sliding shoe ( 60 ). 2. Hydraulic pump according to claim 1, in which the chamber ( 55 ) is continuously connected via a branch channel ( 62 ) in the valve base ( 3 ) to the step bore ( 12 ) receiving the first pilot valve ( 4 ). 3. Hydraulic pump according to claim 1 or 2, wherein the stepped bore ( 12 ) in the valve base ( 3 ) via channels ( 39 , 43 , 44 ) in the valve base ( 3 ) and in the reversing housing ( 25 ) to a length section ( 47 ) of the reversing piston ( 48 ) with the larger effective area ( 59 ) leading space ( 45 ) in the reversing housing ( 25 ) and via channels ( 40 , 41 , 42 ) in the wall ( 29 ) of the cylinder housing ( 2 ) and in the end cap ( 11 ) to the the second pilot valve ( 5 ) receiving the stepped bore ( 13 ) in the end cap ( 11 ) is connected. 4. Hydraulic pump according to one of claims 1 to 3, in which the stepped bore ( 13 ) in the end cap ( 11 ) via a transverse channel ( 49 ) to the atmosphere (A) is closed. 5. Hydraulic pump according to one of claims 1 to 4, wherein the air piston ( 6 ) in coaxial alignment with the hydraulic piston ( 7 ) with a relatively movable through the valve bottom ( 3 ), on the one hand via a suction valve ( 64 ) to the suction line ( 66 ) and on the other hand, via a pressure valve ( 67 ) connected to the pressure line ( 68 ), the second hydraulic piston ( 7 a) is non-positively connected. 6. Hydraulic pump according to one of claims 1 to 4, wherein the air piston ( 6 ) via a valve rod ( 3 ) relatively movable penetrating linkage ( 73 ) ge against the restoring force in the working space ( 34 ) between the air piston ( 6 ) and End cap ( 11 ) incorporated spring ( 74 ) is manually displaceable, the connection between the chamber ( 55 ) and the working space ( 34 ) lying between the end cap ( 11 ) and the air piston ( 6 ) being closed. 7. Hydraulic pump according to claim 6, in which a linkage ( 73 ) associated with the hand lever ( 75 ) can be locked.