DE10164392B4 - Hydraulic steering device - Google Patents

Abstract

Hydraulic steering device in the "non-reaction" design, comprising a housing (1) with a rotary valve control valve and a metering pump (2) attached to the housing (1), wherein the rotary valve control valve comprises an outer control sleeve (3) and an inner control piston (4) consists,
- Which are arranged concentrically to each other, are rotatable relative to each other to a limited extent and with each other and with the metering pump (2) have corresponding holes and channels and
- Form one opened in the neutral position short-circuit path (23), a closed in the neutral position return path (21) and a closed in the neutral position Zulaufpfad (20), wherein
- The inlet path (20) in the direction of the steering cylinder (19) opening check valve (29) leading to the Kurzschlusspfad (23) branch (22), the metering pump (2) and a commutator (26) for the inlet to the metering pump (2 ), a commutator throttle (27) for the drain from the metering pump (2) and a cylinder inlet throttle (28) receives,
characterized in that the check valve (29) between ...

Description

The The invention relates to a hydraulic steering device the preamble of claim 1.

such Steering equipment works fully hydraulically and preferably Used to steer heavy and slow moving vehicles.

Such a steering device is for example in the DE 3814 508 A1 described. Thereafter, the steering device consists in the main of a housing with an inlet port for a supply pump, a drain port for a tank and two directional connections for the inlet to a steering cylinder and the return from the steering cylinder. In the housing, a rotary valve control valve is housed, which consists of an outer, fitted in the housing control sleeve and an inner, concentric with the control sleeve arranged control piston, both of which are rotatable relative to the force of a spring and limited to each other. The steering device also includes a working according to the orbit principle metering pump, which is flanged to the housing and which consists of a fixed outer ring with, for example, seven internal teeth and a rotating rotor gear with then six external teeth. Thus, seven volume-variable chambers are formed in the metering pump.

Of the in the case accommodated control piston of the rotary valve control valve is on the one hand mechanically with a steering wheel and on the other hand via a drive shaft mechanically with the rotor gear connected to the dosing pump while the rotary valve control valve with the volume variable chambers of the metering pump via commutator in hydraulic Connection stand.

To have the control piston and the control sleeve radial bores and radial and axial channels the together several adjustable and parallel throttles form. These throttles cause the applied oil flow in the neutral position of the rotary valve control valve over open short circuit lines is returned to the tank, while the oil flow in a deflected position of the rotary valve control valve in a short-circuit current and divided into a metered working current is, wherein the metered working flow through one of the two cylinder lines led to the steering cylinder becomes. In the main line there is also a direction towards Steering motor opening check valve.

It has now been shown that in steering devices of this kind, the are executed as non-reaction, which means no transmission the road resistance allow on the steering wheel, in special situations unwanted movements occur on the steering wheel. Such a situation occurs when the steering wheel first is directed against the stop and then released. Then the steering wheel does not just turn over on the way to the neutral position maximum deflection angle of the rotary valve control valve of 9 ° as it should be, but depending on the degree of steering capacity up to one half turn of the steering wheel. This is the following technical problem based. When steering against the stop and then releasing of the steering wheel, the control piston tries by the force of the spring element, to return to the neutral position to the control sleeve. It stands to the control piston and thus the steering wheel actually a way over a Twist angle of 9 ° available. On opens this way to neutral position but again the short-circuit choke, whereby a part of the supplied oil flow over the Short circuit path is led into the tank. This reduces also the pressure in the area in front of the metering pump, while the pressure between the Dosing and the steering cylinder initially maintained. This pressure difference loads the metering pump and acts on it Dosing pump mechanically on the control sleeve, so that the control sleeve stopped is approaching that Advance spool. Due to the rectified and superimposed Rotary movement of the control piston and the control sleeve extends the path until the Control piston the control sleeve has caught up and is again neutral to her.

Of the The invention is therefore based on the object, the control system of a generic steering device train so that the transition from the maximum deflected position to the neutral position Advance of the control sleeve is avoided. This object is in the generic steering device solved by the characterizing features of claim 1. Further design options emerge from the dependent claims 2 to 6.

The new steering device eliminates the functional disadvantage of the state the technique and increased thus the utility value of the steering device. On top of that is the new one Steering device simple in construction and therefore both in constructive as well as in production terms very cost-effective.

The invention is based on two Ausfüh Examples are explained in more detail.

To demonstrate:

1 : a hydraulic steering device on average,

2 a simplified circuit diagram of the steering device,

3 : a schematic representation of a first embodiment and

4 : a schematic representation of a second embodiment.

After 1 consists of the hydraulic steering device in the main of a housing 1 with a rotary valve control valve and a working according to the gerotor principle metering pump 2 , the front side of the housing 1 is flanged, wherein the rotary valve control valve from an outer, in the housing 1 fitted control sleeve 3 and an inner, in the control sleeve 3 running control piston 4 is formed. The dosing pump 2 consists of an internally toothed outer ring 5 and an externally toothed, less toothed rotor 6 , which between them several volume variable displacement chambers 7 form. These displacement chambers 7 are via channels in the housing 1 hydraulically connected to the rotary valve control valve and to a double-acting steering cylinder. The dosing pump 2 is with a lid 8th and a washer 9 with the housing 1 screwed.

The internal control piston 4 the rotary valve control valve has a rotationally fixed connection with a handwheel, not shown. Inside the control piston 4 is a drive shaft 10 arranged, on the one hand via a spherical hub profile with the rotor 6 the dosing pump 2 and then on the other hand, the control piston 4 penetrating pen 11 with the outer control sleeve 3 connected. This pen 11 limited in conjunction with an enlarged bore in the inner spool 4 the angle of rotation between the control sleeve 3 and the control piston 4 at about 9 °. The control sleeve 3 and the control piston 4 are supported within the limited angle of rotation by a radially arranged spring element 12 each other off.

This steering device has after the 2 an inlet connection 13 for connection to a supply pump 14 , a return port 15 for connection to a tank 16 , as well as a cylinder connection 17 for clockwise rotation and a cylinder connection 18 for the left turn. Both cylinder connections 17 . 18 connect the steering device with the two cylinder chambers of a double-acting steering cylinder 19 , The steering device has to connect the supply pump 14 with the one cylinder chamber of the steering cylinder 19 an inlet path 20 and for connecting the other cylinder chamber of the steering cylinder 19 with the tank 16 a return path 21 , The inlet path 20 owns a branch 22 from which a short circuit path 23 to the return path 21 leads. In the short circuit path 23 there is an adjustable short-circuit choke 24 , which is open in the neutral position. Also, in the return path 21 an adjustable cylinder return throttle 25 arranged, which is closed in the neutral position.

In the inlet path 20 is the one from the outer ring 5 and the rotor 6 formed metering pump 2 , In the flow direction to the steering cylinder 19 are in front of the dosing pump 2 an adjustable commutator choke 26 for the inlet to the dosing pump 2 and behind the dosing pump 2 an adjustable commutator choke 27 for the drain of the dosing pump 2 arranged, which are both closed in the neutral position. Also closed in the neutral position is an adjustable cylinder inlet throttle 28 , in the flow direction behind the commutator 27 for the drain of the dosing pump 2 is arranged.

According to the invention is located in the area between the branch 22 for the short circuit path 23 and the cylinder inlet throttle 28 of the inlet path 20 one in the flow direction to the steering cylinder 19 opening check valve 29 , to which a parallel arranged, spring-loaded and oppositely acting safety valve 30 is switched.

For constructive arrangement of the check valve 29 show the 3 and 4 two embodiments of the invention, both 3 and 4 the control sleeve 3 and the control piston invisibly shown 4 show in the neutral position. First, the short-circuit choke 24 recognizable, consisting of several circumferentially distributed short-circuit holes 31 in the control sleeve 3 and axial shorting slots 32 in the control piston 4 is formed. In this neutral position are the short-circuit holes 31 and the shorting slots 32 in surplus. Not in overlap, however, are the commutator chokes 26 and 27 , the cylinder inlet throttle 28 and the cylinder return throttle 25 , These are the commutator choke 26 for the inlet to the dosing pump 2 and the commutator choke 27 for the drain of the dosing pump 2 on a common radial plane. The commutator choke 26 for the inlet to the dosing pump 2 is through radial commutator holes 33 in the control sleeve 3 and axial commutator grooves 34 in the control piston 4 formed and the commutator choke 27 for the drain of the dosing pump 2 consists of commutator bores 35 in the control sleeve 3 and from axial inlet grooves 36 in the control piston 4 ,

In contrast, there is the cylinder inlet throttle 28 from inlet bores 37 in the control sleeve 3 and from the axial inlet grooves 36 in the control piston 4 and the cylinder return throttle 25 from return bores 38 in the control sleeve 3 and return grooves 39 in the control piston 4 ,

After 3 is the check valve 29 in the first embodiment of the invention immediately behind the branch 22 of the inlet path 20 , For this purpose, the rotary valve control valve in a special way with a ring channel 40 for the short-circuit reactor 24 and with an entrance ring channel 41 for access to the commutator chokes 26 and 27 equipped. Both ring channels 40 and 41 are in the case 1 introduced the steering device and each via a line 42 or via an input line 43 directly with the branch 22 of the inlet path 20 connected. This is the check valve 29 in the to the entrance ring channel 41 leading input line 43 , Parallel to the check valve 29 is the safety valve 30 arranged.

According to the 4 is the check valve according to the invention 29 behind the dosing pump 2 between the radial planes of the commutator choke 27 and the cylinder inlet throttle 28 arranged. These are the axial inlet grooves in this area 36 in the control piston 4 interrupted and each in a first Zulaufnut 44 and a second feed groove 45 separated. All first inlet grooves 44 are through a ring channel 46 and all second feed grooves 45 through a ring channel 47 connected. In the control sleeve 3 are located in the radial plane of the annular channel 46 radial bores 48 in a ring channel 49 open in the housing and in the radial plane of the annular channel 47 are radial holes 50 arranged in an annular channel 51 lead. Both ring channels 49 and 51 are over a connection line 52 short-circuited, in turn, in turn, the check valve 29 and the immediate safety valve 30 are located.

When not operated steering device, the rotary valve control valve is in the neutral position, where the inner control piston 4 and the outer control sleeve 3 center and all to the dosing pump 2 and to the steering cylinder 19 leading connections are closed ge. The oil flows from the inlet connection 13 over the open short-circuit choke 24 of the rotary valve control valve directly to the tank 16 back.

Upon deflection of the rotary valve control valve, the control piston 4 and the control sleeve 3 against the force of the spring element 12 twisted from its middle position into a working position, whereby the flow of oil into a tank 16 leading short-circuit current and in one to the steering cylinder 19 leading working current is split. The proportional working current is through the metering pump 2 dimensioned as needed and then the steering cylinder 19 made available. The oil passes in the embodiment of the 2 and 3 For example, in a clockwise rotation initially the unloaded check valve 29 and then successively the commutator choke 26 for the inlet to the dosing pump 2 , the dosing pump 2 , the commutator choke 27 for the drain of the dosing pump 2 and the cylinder inlet throttle 28 before the oil is the steering cylinder 19 loaded. This case from the steering cylinder 19 displaced oil passes through the return path 21 directly into the tank 16 ,

At full deflection of the rotary valve control valve, the short circuit path is closed and all the oil reaches the steering cylinder 19 ,

If after such a full deflection of the rotary valve control valve, the steering wheel is released, then the spring element acts 12 of the rotary valve control valve on the control piston 4 and twist it back towards the neutral position. Here again the short-circuit choke 24 opened so that part of the provided oil flow to the tank 16 flows. This reduces the pressure in front of the check valve 29 while the pressure behind the check valve 29 preserved. This pressure difference causes the closure of the check valve 29 until, by a renewed deflection again a balanced pressure ratio at the check valve 29 has set. During this time, the spans behind the check valve 29 acting pressure the metering pump 2 and thus the control sleeve 4 firmly on. After reaching a maximum allowable pressure behind the check valve 29 opens the safety valve set to this value 30 and relaxes the existing pressure column.

1

casing

2

metering

3

control sleeve

4

spool

5

outer ring

6

rotor

7

displacer chamber

8th

cover

9

washer

10

drive shaft

11

pen

12

spring element

13

inflow connection

14

supply pump

15

Return connection

16

tank

17

cylinder port Right

18

cylinder port Left

19

steering cylinder

20

supply path

21

Return path

22

junction

23

Short-circuit path

24

Short throttle

25

Cylinder return throttle

26

Kommutatordrossel for the Inlet to the dosing pump

27

Kommutatordrossel for the Drain from the dosing pump

28

Cylinder inlet throttle

29

check valve

30

safety valve

31

Short hole

32

Kurzschlussnut

33

commutator

34

Kommutatornut

35

commutator

36

Zulaufnut

37

inlet bore

38

Return bore

39

return groove

40

annular channel

41

Input annular channel

42

management

43

input line

44

first Zulaufnut

45

second Zulaufnut

46

annular channel

47

annular channel

48

radial drilling

49

annular channel

50

radial drilling

51

annular channel

52

connecting line

Claims (6)

Hydraulic steering device in the "non-reaction" version, consisting of a housing ( 1 ) with a rotary valve control valve and a housing ( 1 ) ( 2 ), wherein the rotary valve control valve from an outer control sleeve ( 3 ) and an inner control piston ( 4 ), which are arranged concentrically to each other, are rotatable relative to each other to a limited extent and with each other and with the metering pump ( 2 ) have corresponding bores and channels and - which has a short-circuit path opened in the neutral position ( 23 ), a closed in the neutral position return path ( 21 ) and a closed in the neutral position Zulaufpfad ( 20 ), wherein - the feed path ( 20 ) towards the steering cylinder ( 19 ) opening check valve ( 29 ), a short circuit path ( 23 ) leading branch ( 22 ), the dosing pump ( 2 ) and a commutator choke ( 26 ) for the feed to the metering pump ( 2 ), a commutator choke ( 27 ) for the drain from the dosing pump ( 2 ) and a cylinder inlet throttle ( 28 ), characterized in that the check valve ( 29 ) between the short circuit path ( 23 ) leading branch ( 22 ) and the cylinder inlet throttle ( 28 ) is located. Hydraulic steering device according to claim 1, characterized in that the check valve ( 29 ) between the branch ( 22 ) and the dosing pump ( 2 ) is arranged. Hydraulic steering device according to claim 2, characterized in that a short-circuiting choke ( 24 ) one the short-circuit bores ( 31 ) in the control sleeve ( 3 ) connecting ring channel ( 40 ) and the access area to the commutator choke ( 26 ) for the feed to the metering pump ( 2 ) an entrance ring channel ( 41 ), wherein the input ring channel ( 41 ) via an input line ( 43 ) with the branch ( 22 ), in which the check valve ( 29 ) is located. Hydraulic steering device according to claim 1, characterized in that the check valve ( 29 ) between the dosing pump ( 2 ) and the cylinder inlet throttle ( 28 ) is arranged. Hydraulic steering device according to claim 4, characterized in that each inlet groove ( 36 ) in the control piston ( 4 ) from a first inlet groove ( 44 ) and a second inlet groove ( 45 ) and all first inlet grooves ( 44 ) through an annular channel ( 46 ) and all second feed grooves ( 45 ) through an annular channel ( 47 ), wherein both ring channels ( 46 . 47 ) via radial bores ( 48 . 50 ) in the control sleeve ( 3 ) Access to one ring channel each ( 49 . 51 ), both via a connecting line ( 52 ), in which the check valve ( 29 ) is located. Hydraulic steering device according to claim 1, characterized in that a check valve ( 29 ) and the pressure in front of the closing non-return valve ( 29 ) to a desired value limiting safety valve ( 30 ) is provided.