EP1623653A1 - Hydraulic apparatus - Google Patents

Abstract

The device has a lifting piston contained in a lifting cylinder (3), and a pump piston moved within a pump cylinder (9). The lifting cylinder, the pump cylinder and a tank chamber are each formed by a compartment belonging to a profile tube (2). Two tension rod compartments are provided in the profile tube, where the lifting cylinder compartment is positioned in center of the profile tube.

Description

Such a hydraulic device is known from DE 43 40 236 A1. The hydraulic device described there is particularly for a chair with pedal-operated seat height adjustment, as this is used for example in a barber chair determined. The hydraulic unit consists of a lifting unit with lifting cylinder and reciprocating piston as well as a pump unit with pump cylinder and pump piston. The pump piston is actuated against the action of a spring by means of a pumping lever, wherein the pump cylinder is connected via a hydraulic line to the lifting cylinder. A valve is arranged in the hydraulic channel between the pressure chamber of the pump cylinder and the lifting cylinder and opens upon actuation of the pump piston, whereby a hydraulic fluid flow to Hubzylinderraum is possible.

The known hydraulic device has a second valve, which allows a subsequent flow of hydraulic fluid into the pressure chamber within the pump cylinder, below the pump piston.

The known hydraulic device consists of a housing in which a hydraulic cylinder and a tank space are provided. Furthermore, a pump cylinder is screwed into a bottom plate of the housing, which ends with its free end in the tank space.

In other known devices, not only the pump cylinder, but also the hydraulic cylinder is screwed into a bottom plate.

Although this known hydraulic device has been proven in practice, it is desirable to make changes that ensure a more cost-effective production with at least the same good functionality.

This object is solved by the features of patent claim 1.

Further developments of the invention are described in the subclaims.

The basic idea of the invention is to reduce the number of individual parts and thereby enable a more cost-effective production. This is inventively achieved in that the side walls of the lift cylinder, the side walls of the pump cylinder and the side walls of at least one tank space are formed by at least one chamber of a profile tube. The profile tube is preferably made of aluminum and is advantageously designed as a cost extruded profile.

A particular advantage results from the fact that in addition to the lifting cylinder, the pump cylinder and the tank or tanks additionally required for fastening a lid and a bottom part Zugankerkammern for tie bolts are an integral part of the profile tube and thereby simultaneously contribute to the stabilization of the entire profile tube. The tie rod chambers serve to guide the screw and facilitate the screwing of the connecting screws into the threaded holes provided in the bottom part.

A particularly stable and insensitive to unintentional deformation during processing embodiment is obtained when the lifting cylinder chamber is arranged centrally in the profile tube and the other chambers between the profile tube wall and the Hubzylinderkammer are arranged. It is advantageously provided that adjacent chambers are connected to each other via the chamber walls or additional connecting walls. Particularly stable is an embodiment in which the two Zugankerkammern, the pump cylinder chamber and an additional reserve chamber offset by 90 ° are arranged around the centric Hubzylinderkammer around.

The chambers formed between the tie rods and the reserve chamber and the pump cylinder chamber serve as tank spaces communicating with each other, preferably via grooves, are connected. In this case, connecting openings should be provided in the upper and in the lower region of the tank chambers, in order not only to allow a hydraulic fluid exchange, but also an exchange of air in the upper region.

Furthermore, it should be emphasized as particularly advantageous that both non-return valve openings are arranged coaxially to each other, whereby the construction of the valve units is substantially simplified. The two valve openings are delimited from each other by an insert member within the pump cylinder, wherein the insert part can be screwed into a bottom plate which can be placed on the profile tube, whereby this at the same time positions the profile tube on the base plate. The counterpart takes over an opposite of the insert provided in the pump cylinder and screwed into a lid Guide part, which, inter alia, has the task to guide the Pumpenstö-βel axially and absorb the seal.

It is of particular advantage if the insert used in the hydraulic device according to the invention from a prefabricated polygon, preferably hexagonal material is produced, which on the one hand gives a secure cylindrical coaxial fixation between the profile tube and bottom part and form through the remaining open spaces flow channels, which in cooperation with the overlying flexible valve plate as a suction valve allow the suction of the hydraulic fluid in the pump cylinder chamber.

It has proved to be advantageous to provide a good pressure point at the end of the pump stroke and before the start of the lowering stroke on the pump lever. For this purpose, a strongly dimensioned open spring steel ring is arranged in connection with a partially conical bushing at the upper end of the pump plunger. Upon actuation of the pump lever and before the beginning of the Absenkhubes the spring steel ring comes in the conical part of the bushing to the plant and opposes intentional further pushing the pump lever by pressing into the cone and thus strong radial deformation plus friction against the pump plunger high axial force. This strongly swelling force signals the person operating the pump lever that now the lowering movement is initiated, whereby an increased attention in the operator when operating the pump lever is achieved and unintentional short "lowering" is avoided. The coaxial with the spring steel ring lying elastic ring serves both the centering of the spring steel ring and the additional reinforcement of the spring force.

The invention will be explained in more detail below with reference to an embodiment in connection with six figures.

Fig. 1

einen Axialschnitt durch das erfindungsgemäße Hydraulikgerät,

Fig. 2

eine detaillierte Schnittdarstellung des Pumpenzylinders mit Anbauten gemäß Fig. 1,

Fig. 3

einen Axialschnitt durch ein Einsatzteil,

Fig. 4

eine Draufsicht auf ein Einsatzteil,

Fig. 5

eine perspektivische Darstellung eines Profilrohrs und

Fig. 6

eine klapprichtige Darstellung des Profilrohrs.

Showing:

Fig. 1

an axial section through the hydraulic device according to the invention,

Fig. 2

a detailed sectional view of the pump cylinder with attachments of FIG. 1,

Fig. 3

an axial section through an insert part,

Fig. 4

a top view of an insert part,

Fig. 5

a perspective view of a profile tube and

Fig. 6

a klappprichtige representation of the profile tube.

The hydraulic device 1 shown in Fig. 1 is used as a pedal operated guide and height adjustment for e.g. a chair, table, pallet or shelf determined and suitable. Seat height adjustment, e.g. a barber chair or similar treatment chair, determined and suitable.

The hydraulic device consists essentially of an extruded aluminum profile tube 2 with a plurality of chambers. In the center of the profile tube 2, a lifting cylinder chamber 3 is provided. Between the Hubzylinderkammer 3 and a profile tube wall 4, two diametrically arranged Zugankerkammern 5, 6 are provided, on the one hand directly to the profile tube wall and the other via connecting walls 7.8 with the Hubzylinderkammer third are connected. By 90 ° offset to this and also diametrically a pump cylinder chamber 9 and a reserve chamber 10 are provided. Furthermore, four tank chambers 11, 12, 13, 14 are formed by the profile tube 2.

The tank chamber 11 is limited by the Hubzylinderwand 15, the wall 16, the tie rod 5, the profile tube wall 4 and the wall 17 of the reserve chamber 10. The wall 16 of the tie rod 5 has a continuous longitudinal opening to the tank chamber 11.

The tank chamber 12 is arranged adjacent to the tank chamber 11 and is limited by the lifting cylinder wall 15, the wall of the pump cylinder chamber 18, the profile tube wall 4 and the lifting cylinder wall 15th

The tank chamber 13 is arranged diametrically to the tank chamber 11 and is bounded laterally by the lifting cylinder wall 15, the wall 18, the pump cylinder chamber 9, the profile tube wall 4 and the wall 19 of the tie rod 6. The wall 19 of the tie rod chamber 6 has a slot-shaped longitudinal opening towards the tank chamber 13 on.

The tank chamber 14 is bounded by the profile wall 4, the lifting cylinder wall 15, the wall 17, the reserve chamber 10 and the wall 19 of the tie rod chamber 6.

The tank chambers 11, 12 are communicatively connected to each other in the lower region via a groove 20. In the upper region of the profile tube 2, the chambers 11, 12 communicating with each other via a groove 21 are interconnected. In this case takes place via the groove 20, a hydraulic fluid exchange and via the groove 21, an air exchange. In an analogous manner, the tank chambers 13, 14th connected communicatively via the grooves 22, 23. The grooves 20, 21, 22, 23 are introduced into the connecting walls 7, 8 which connect the tie rod chambers 5, 6 and the lifting cylinder chamber 3.

The tank chambers 12, 13 and 11, 14 are communicatively connected to each other. For this purpose, on the one hand in the lower region of the wall of the pump cylinder chamber 9, two diametrical grooves 24, 25 are provided. Here, too, are corresponding grooves 26, 27 in the upper region of the wall 18 of the pump cylinder chamber 9. In contrast to the only connecting function of the grooves 20 to 23 and 28 to 31, the grooves 24, 25 as a connection of the pump cylinder chamber with the chambers 12, 13 needed as intake ports for the hydraulic fluid to the double valve. Analogously, the grooves 26, 27 are required for the outflow of hydraulic fluid from the pump cylinder space into the adjacent chambers 12, 13.

The grooves 28, 29, 30, 31 are provided in the upper and in the lower region of the wall 17 of the reserve chamber 10. Of course, only one tank chamber can be used as Hydraulikmittelvorratsbehältnis. In this case, no communicating connection between the tank chambers is necessary.

All chambers, except for the tank chambers 11, 12, 13, 14 have a circular inner cross-section.

At the upper and at the lower end of the profile tube 2 in each case a peripheral shoulder 32, 33 is provided, into which a cylindrical cover 34 or a bottom part 35 can be inserted. The lid 34 is sealed from the peripheral portion 32 by means of a ring seal. To seal the bottom part, two axially spaced annular seals 82, 83 are provided.

In the lifting cylinder chamber 3, an axially displaceable piston is arranged. The load to be lifted, e.g. the seat of the barber chair, is at the upper end of the reciprocating piston 36 on the outer cone 37 a, additionally attached with a screw in the internal thread 37, mounted, which is not shown for clarity. The reciprocating piston 36 is sealed with a sealing ring 38 against a guide sleeve 39 introduced in the cover 34. The guide sleeve 39 is sealed by means of a ring seal 40 with respect to the lifting cylinder chamber 3. Opposite the cover 34, the reciprocating piston 36 is sealed by means of a ring seal 41 situated above the sealing ring 38. Between the seals 38, 40 an unillustrated connection channel is provided to a tank chamber. When the reciprocating piston 36 is in its highest stroke position, via a radial channel 42 in the reciprocating piston, a connection between the tank chamber, the connecting channel, not shown between the seals 38, 40 and filled with hydraulic fluid Hubzylinderkammer 3 via a blind hole 43 in the lower end face made of the reciprocating piston 36. In this uppermost position of the reciprocating piston 36 so hydraulic fluid can escape via the blind hole 43, the channel 42, the connecting channel, not shown, in a tank chamber. This connection is necessary because 36 no Absenkhub the pump piston would be possible due to the back pressure without a connecting channel in the uppermost position of the reciprocating piston. Furthermore, the connection to the tank chamber of the venting of the pumping system, if for example by an inclined position of the hydraulic device 1 air should penetrate.

In the illustrated embodiment, the entire lifting cylinder chamber 3 formed by the profile tube 2 is designed as a lifting cylinder pressure chamber. Below the Hubbodens 3 is for soft impact damping when lowering an elastic ring 84 is provided.

The pump cylinder chamber 9 is divided by a relative to the wall 18 of the pump cylinder chamber 9 sealed pump piston 44 into a pressure chamber 45 and a pump plunger chamber 46, wherein a pump plunger 47 protrudes from the pump piston 44 through the pump plunger chamber 46. The pump plunger chamber 46 is limited at its upper end by a guide sleeve 48 which is screwed into the cover 36 and sealed by a sealing ring 49 with respect to this. The pump plunger 47 continues above the cover 36 with a pressure piece 50, wherein on this and thus on the pump plunger 47 and the pump piston 44, a pump handle 51 a acts. This is connected via an eccentric shaft 51b with the pump lever 51 and hinged to a bearing eye 52 of the lid. A depression of the pump lever 51 thus leads to an axially downward movement of the pump plunger 47. For returning the pump piston 44 with the pump plunger 47, a coil spring 53 is provided, which is supported on the one hand on a peripheral ring 54 on the pump plunger 47 and on the other hand on an annular disc 55 , which is introduced on an annular shoulder 56 in the peripheral wall 18 of the pump cylinder chamber 9. The annular shoulder 56 is made by drilling the extruded profile from the upper side. Therefore, the upper part of the pump cylinder chamber 9 has a larger diameter than the lower part of the pump cylinder chamber. 9

In the bottom part 35, an insert member 57 is screwed, the outer contour of an upper, round over-rotated hexagonal part 58 is formed with circumferential groove 73, a lower threaded portion 59 and an intermediate recess for a sealing ring 69.

With the help of the hexagonal section 58, the profile tube 2 is centered on the bottom part 35. The cover 36 is centered on the guide sleeve 48th

The insert part 57 is hollow. The thus formed, centric, substantially cylindrical cavity 60 within the insert part is connected via a closable passage opening 61 with the overlying pressure chamber 45. In the lower region of the cavity 60, a connecting channel 62 is provided to Hubzylinderkammer 3. Part of the connecting channel 62 is a blind hole 63 in the bottom part 35, which is connected to a trapezoidal recess of the continued in the bottom part 35 Hubzylinderkammer.

Within the cavity 60, designed as a valve ball valve piston 65 is provided, which closes the passage opening 61 due to the spring force of a spring 66.

Between the insert part 57 and the pump cylinder chamber wall 18, a substantially annular supply space 67 is formed. The supply space 67 is arranged concentrically to the passage opening 61 and to the cavity 60. The supply space 67 is communicatively connected via the grooves 24, 25 with the tank chambers 12, 13. Downwards, the supply space 67 is limited by the bottom part 35, wherein the supply space 67 is sealed relative to the lifting cylinder chamber 3 via the sealing rings 68,69.

In the upper region of the supply chamber 67, an annular gap 70 between insert 57 and wall 18 is formed. The annular gap 70 represents a valve opening between the pressure chamber 45 and the supply chamber 67. The annular gap 70 is on all sides of a flat, formed as a ring member 71 formed valve member. The ring member 71 is made of elastic material, preferably polyurethane. The ring member 71 must be elastic and sufficiently stable, on the one hand to seal the annular gap 71 and on the other hand to keep the compressive forces acting on it.

The ring member 71 is mounted axially displaceably in a circumferential groove 72, wherein the circumferential groove 72 is wider than the ring member 71. The ring member 71 is located on the one hand in the circumferential groove 72 and on the other hand on the surface of the insert member 57 sealingly. If the pump piston 44 is moved upward, creates a negative pressure in the pressure chamber 45, whereby the ring member 71 is moved in the axial direction upwards and so a connection between the pressure chamber 45 and the tank chambers 11, 12, 13, 14 is created, whereby hydraulic means in the pressure chamber via the grooves 24, 25, the supply chamber 67, the annular gap 71 and the gap between ring member 71 and insert 57 can flow. If, on the other hand, the pump piston 44 is moved axially downwards, the annular part 71 is pressed sealingly onto the groove wall and the surface of the insert part 57 due to the resulting overpressure. Ideally, the lower groove side wall and the surface of the insert 57 lie exactly in one plane.

A subsequent flow of the hydraulic fluid into the pressure chamber 45 via the supply chamber 67 is facilitated by the insert 57 has a polygonal contour. As a result, connections with large free cross-section between the grooves 24, 25 and the pressure chamber 45 are created. A distribution of the hydraulic fluid within the supply space 67 is ensured by a circumferential groove 73 in the insert part 57.

At the bottom of the pump plunger 47, an actuating pin 74 is provided. This pushes the valve piston 65 after overcoming a pressure point against the force of the spring 66 down, so that the passage opening 61 is released. The reciprocating piston 36 now lowers and displaces hydraulic fluid via the connecting channel 62 and the cavity 60 and the open passage opening 61 in the pressure chamber 45. From there, the hydraulic fluid passes through an opening provided in the wall 18 throttle groove 75 and a channel 76 within the pump piston 44 in the pump plunger chamber 46, and from there via the grooves 26, 27 in the tank chambers 12,13.

It is within the scope of the invention to dispense with the channel 76 in the pump piston 44 and to extend the throttle groove 75 correspondingly in the axial direction. This would have the advantage that can be dispensed with the introduction of the channel 76 in the pump piston 44.

The pressure point after which the actuating pin 74 displaces the valve piston 65 is essentially generated by the spring steel ring 79 arranged below the pressure piece 50 by being pressed into the cone. The operator feels this moment due to the increased power requirement.

The described hydraulic device 1 has the following mode of operation: To actuate the hydraulic device 1, the pump lever 51 is moved downwards, that is to say against the direction of the spring force of the helical spring 53. In this case, the pump piston 44 is moved downward. Under the action of the coil spring 53, the piston 44 and with it the pump lever 51 is returned to its original position. In this suction stroke, the ring member 71 is lifted and releases the annular gap 70. The hydraulic means located in the tank chambers 11, 12, 13, 14 is via the grooves 25, 26th and the supply space 67 and finally the annular gap 70 sucked into the pressure chamber 45 within the pump cylinder chamber 9. During the subsequent pumping stroke, the ring member 71 closes the annular gap 70. The hydraulic fluid under pressure in the pressure chamber opens against the action of the conical spring 66, the ball valve with the valve ball 65, so that the hydraulic fluid through the axially extending passage opening 61 via the cavity 16 within the insert 57th enters the Hubzylinderkammer 3 and raises the piston 36. After completion of the pumping stroke, the valve piston 65 closes the passage opening 61 under the action of the conical spring 66, so that the pressure space 45 remains closed until the next pumping stroke or until the lowering operation described below.

The pumping process can be repeated until the piston 36 has reached its uppermost position. As well as the bore 42 of the piston 36 has reached a not shown, projecting into the plane of connection between the seals 38 and 41 located connection to a tank chamber, the hydraulic fluid flows back via this connection in the tank chambers. A further lifting of the piston 36 is thus prevented.

If the lowering is deliberately initiated, the clearly recognizable pressure point must be overcome at the moment where the top of the pump plunger 47 running spring steel ring 79 in the conical part 77 of the sleeve 80 to further move the pump plunger 57 down.

For lowering the reciprocating piston 36, the pump lever 51 and the pump handle 51 a in its lowest position, ie to move to the end stop of the pressure piece 50 on the sleeve 80. In this position, the actuating pin 74 hits the valve ball 65. This releases the through-hole 61, whereby hydraulic fluid from the lifting cylinder chamber 3 in the pressure chamber 45 and from there via the throttle groove 75 in the pump plunger chamber 46 and from there via the grooves 26, 27 into the tank chambers 12, 13 passes.

LIST OF REFERENCE NUMBERS

1

hydraulic equipment

2

section tube

3

jack cylinder

4

Profile pipe wall

5

Zugankerkammer

6

Zugankerkammer

7

connecting wall

8th

connecting wall

9

Pump cylinder chamber

10

reserve chamber

11, 12, 13, 14

tank chambers

15

Hubzylinderwand

16

wall

17

wall

18

wall

19

wall

20

groove

21

groove

22

groove

23

groove

24

groove

25

groove

26

groove

27

groove

28

groove

29

groove

30

groove

31

groove

32

Circumferential paragraph (above)

33

Circumferential paragraph (below)

34

cover

35

the bottom part

36

reciprocating

37

threaded hole

37a

outer cone

38

sealing ring

39

guide sleeve

40

ring seal

41

ring seal

42

channel

43

blind

44

pump pistons

45

pressure chamber

46

Pump plunger space

47

pump plunger

48

guide sleeve

49

seal

50

Pressure piece

51

pump lever

51a

pump bracket

51b

eccentric shaft

52

bearing eye

53

coil spring

54

peripheral ring

55

washer

56

annular shoulder

57

insert

58

Hexagonal section

59

threaded portion

60

cavity

61

Through opening

62

connecting channel

63

Blind hole

65

Valve piston (valve ball)

66

feather

67

supply room

68

seal

69

poetry

70

annular gap

71

Ring part (valve element)

72

circumferential groove

73

circumferential groove

74

actuating pin

75

throttle notch

76

channel

77

cone

78

Plastic ring

79

Spring steel ring

80

Rifle

81

ring seal

82

ring seal

83

ring seal

84

ring

Claims (26)

Hydraulic device with a lifting piston guided in a lifting cylinder, with a pump piston movable in a pump cylinder, with a tank space for a hydraulic fluid, with two valve units,
characterized in that the lifting cylinder (3), the pump cylinder (9) and the tank space (11, 12, 13, 14) by at least one chamber (3, 9, 11, 12, 13, 14) of a profile tube (2) are formed. Hydraulic device according to claim 1,
characterized in that the profile tube (2) is an extruded profile, preferably made of aluminum. Hydraulic device according to one of the preceding claims
characterized in that in the profile tube (2) at least one, preferably two, tie rod chambers (5, 6) are provided. Hydraulic device according to one of the preceding claims,
characterized in that in the profile tube (2) a reserve chamber (10) is provided. Hydraulic device according to one of the preceding claims,
characterized in that the lifting cylinder chamber (3) is arranged centrally in the profile tube (2). Hydraulic device according to claim 5,
characterized in that the two tie rod chambers (5, 6), the pump cylinder chamber (9) and the reserve chamber (10) between the Hubzylinderkammer (3) and the profile tube wall (15), preferably offset by 90 °, are arranged. Hydraulic device according to claim 6,
characterized in that the tie rod chambers (5, 6), the pump cylinder chamber (9) and the reserve chamber (10) are each connected to the profile tube wall (4) and lifting cylinder chamber (3) and thus form four tank chambers (11, 12, 13, 14) , Hydraulic device according to claim 7,
characterized in that at least two adjacent tank chambers (11, 12) (12, 13) (13, 14) (14, 11), preferably all adjacent tank chambers, are communicatively connected. Hydraulic device according to one of claims 7 or 8,
characterized in that the tie rod chambers (5, 6) are open to at least one adjacent tank chamber (11, 13). Hydraulic device according to one of the preceding claims
characterized in that the entire hydraulic chamber (3) is designed as a pressure chamber. Hydraulic device according to one of the preceding claims
characterized in that a pump piston (44) divides the pump cylinder chamber (9) into a pressure chamber (45) and into a pump tappet space (46). Hydraulic device according to claim 11,
characterized in that in the upper region of the pump tappet space (46) has a connection opening (26, 27) to a tank chamber (12, 13) is provided. Hydraulic device according to one of claims 11 or 12,
characterized in that adjacent to the pressure chamber (45), preferably below the pressure chamber (45), a communicating with at least one tank chamber (12, 13) connected supply space (67) is provided, wherein between the pressure chamber (45) and supply space (67) , Preferably axial, by means of a valve element (71) closable valve opening (70) is provided. Hydraulic device according to claim 13,
characterized in that the supply space (67) in the radial direction on the one hand at least partially by the pump cylinder chamber inner wall and on the other hand at least partially by the peripheral wall of at least partially within the pump cylinder chamber (9) arranged insert part (57) is limited. Hydraulic device according to claim 13,
characterized in that the insert part (57) is designed as a polygonal part, preferably as an over-turned hexagonal part. Hydraulic device according to claim 13,
characterized in that in the insert part (57) has a circumferential groove is introduced. Hydraulic device according to one of claims 14 or 15, characterized
characterized in that the valve opening (70) between the supply space and the pressure chamber is formed by an axially extending, preferably on the outer contour of a circular and on the inner contour mehrkantigem, gap between the insert and the pump cylinder chamber inner wall. Hydraulic device according to claim 17,
characterized in that the valve element (71) as, preferably flat and elastic, ring part is formed. Hydraulic device according to one of claims 17 or 18,
characterized in that the valve element (71), preferably in a circumferential groove (72) in the pump cylinder wall, is mounted axially displaceable and the annular gap (70) between the insert part (57) and the pump cylinder chamber inner wall surmounted and upon pressurization of the pressure chamber (45 ) seals the annular gap (70) and preferably rests sealingly on the one hand on the lower annular surface of the groove (72) and on the other hand on the surface of the insert part (57). Hydraulic device according to one of claims 14 to 19,
characterized in that the insert part (57) in a bottom part (35) can be screwed. Hydraulic device according to one of claims 14 to 20,
characterized in that the insert part (57) is provided with a preferably centric cavity (60) with a closable passage opening (61) to the pressure space (45), wherein between the Through hole (61) and the hydraulic cylinder chamber, a hydraulic fluid channel is provided. Hydraulic device according to claim 20,
characterized in that the passage opening (61) by means of a, preferably spring-loaded, preferably designed as a ball, within the cavity (60) arranged valve piston (65) is closable. Hydraulic device according to claim 22,
characterized in that the valve piston (65) by means of an actuating pin (74) counter to the direction of a spring force is movable, so that the passage opening (61) can be flowed through by hydraulic means. Hydraulic device according to claim 22,
characterized in that the actuating pin (74) coaxially on the pump plunger bottom, preferably in exactly tuned length, is arranged. Hydraulic device according to one of the preceding claims,
characterized in that in the pump cylinder chamber wall at least one throttle notch (75) is provided, wherein the throttle notch (75) at a corresponding axial position of the pump piston (44) within the pump cylinder chamber (9), a hydraulic fluid flow channel from the pressure chamber (45) in the pump tappet space (46). forms. Hydraulic device according to one of the preceding claims,
characterized in that within the pump piston (44) a hydraulic fluid channel (76) is provided which forms together with a throttle notch (75) within the pump cylinder chamber wall a hydraulic fluid flow channel from the pressure chamber (45) in the pump plunger chamber (46).

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