DE1628119A1 - Hydraulic system with a hydraulic motor - Google Patents

Description

• Hydraulic system with a hydraulic motor

The invention "relates to a hydraulic system with a hydraulic motor, with a four-way switch valve that leads to a pressure line, a drain line and two to the motor- » de has working channels that are in two active switch positions on both sides of a neutral position via switchover openings are connected to the pressure and discharge lines, and to a flow control valve connected in parallel to the switching valve, which is controlled as a function of the pressure drop at an adjustable measuring orifice that flows through the motor Liquid flows through.

A hydraulic system is known in which the changeover valve on the one hand and the Ilengen regulating valve with measuring orifice on the other hand each form a structural unit. The aperture

is located in the pressure line to the switching valve. To reverse the direction, the measuring orifice must first be adjusted so that the amount of liquid supplied to the motor is very small before the switch can be made. If this is not observed, the system can be damaged. Furthermore , it is difficult to control the speed to keep the motor constant,

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for example if this is heavily loaded (uphill) and leakage losses occur to a greater extent. Braking the motor also brings problems, as this is due to the inertia of the moving parts acts as a pump and possibly generates a negative pressure between the closed measuring orifice and itself. Overall, the control arrangement for such a system is great it takes up a lot of space, numerous individual parts and connection channels.

The invention is based on the task of eliminating these disadvantages entirely or to fix it in part.

According to the invention, this object is achieved in that the adjustable Part of the measuring orifice connected to the adjustable part of the switching valve and the switching valve in the switching valve is arranged.

This results in a common adjustment of the measuring orifice and the switchover valve, so that not only the handling is simpler, but also no switching can take place without first reducing the amount of liquid supplied to the motor can. Furthermore, the combination of the switching valve, the flow control valve and the orifice plate increases the space and effort involved saved up. In particular, numerous connection channels running from one device to another can be omitted.

It is particularly advantageous if the adjustable Keßblende is in the drainage line. If the measuring orifice is closed, there is a strong emergency braking of the motor, because that Line is blocked through which the Kotor as a result of its pumping action Wants to promote liquid. Furthermore, the Kotor has a very constant speed, as the speed in the drain line Orifice plate measures the fluid actually doing work in the engine, thus ignoring the leakage losses.

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BATH

It is particularly useful here if the orifice plate in the parts of the two active positions immediately adjacent to the neutral position are completely closed. This leads to, that even before the actual neutral position is reached, a braking effect takes place. Thus, the neutral position can itself from be free of any braking effect. In particular, the two working areas can be connected to one another in the neutral position will. The Kotor then works in freewheeling mode, which is very beneficial for many purposes.

For the working method described, it is recommended if the both working channels via a pressure relief valve each with the drain line are connected behind the Keßblende. T7enn namely in the 3 braking position too high a pressure in the respective return line of the liotor arises, this can be done through the pressure relief valve can be limited to a specified value.

So that the Keßblende take even better account of leakage oil losses it is advisable to influence it from the inlet pressure in such a way that it enlarges its opening with increasing pressure.

Furthermore, the switching valve can be two concentric to one another and have sleeves rotatable relative to one another, of which at least one opening and the other one of the openings in the circumferential direction corresponding cover. This results in a particularly simple connection between Keßblende and changeover valve. Here should the cover in the circumferential direction somewhat wider than the opening be so that there is a braking position on either side of the neutral position results.

Taking advantage of a standard for switching valves. Sleeve with Switchover openings that interact with longitudinal grooves of the other sleeve, expediently through the opening of the measuring orifice Extension formed at least one such longitudinal groove.

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In a preferred embodiment, a piston which can be axially displaced against spring force is located in the interior of the sleeve End faces acted upon by the pressure on both sides of the orifice plate and together with an axially held part form the flow control valve. Here you can use the LIeS aperture connected longitudinal grooves take on a further function if they extend beyond the piston and over a transverse channel connected to the face space on the other side of the piston are.

In addition, the longitudinal grooves connected to the orifice plate can be connected to the pressure line in the neutral position. This ensures that the flow control valve is under the full pressure of the system in the neutral position and accordingly opens completely, i.e. the entire delivery rate of the pump bypasses the switching valve.

In a further embodiment of the invention, it is ensured that that the free opening cross-section of the measuring orifice increases steadily with the angle of rotation and that the outer sleeve of the switching valve is axially and thus the maximum free opening cross-section the orifice plate is adjustable. It is known to use the maximum free opening cross-section of a measuring orifice for the purpose of adaptation to adjust to the pump. In the present case, the outer sleeve of the switchover valve is made adjustable for this adaptation. An eccentric can simply serve as the adjusting element.

Then it has proven to be useful if the outer sleeve is in the area of a hanging channel that connects to the pressure line is connected, has an increase in diameter, and when connected between the adjusting member and the sleeve, an elastic element is. This can be done, for example, by an elastic ring placed around an eccentric pin of the adjusting element exist. As a result of the increase in diameter, the sleeve is standing

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tinter the influence of part of the inlet pressure. According to the The restoring force of the elastic element establishes a state of equilibrium which results in a certain axial displacement of the Sleeve and thus an adaptation of the lower diaphragm cross-head . causes the inlet pressure to compensate for leakage losses with the result that the engine speed remains constant.

The invention is explained in more detail below in connection with an exemplary embodiment shown in the drawing. Show it"

Pig. 1 is a schematic representation of the hydraulic System,

Pig. 2 a longitudinal section through the combined TJmschalt- and flow control valve according to line II-II in Pig. 4,

Pig. 3 is a fragmentary view along line III-III of Pig. 2,

Pig. 4 shows a partial cross-section along the line IV-IV of FIG . 2,

Pig. 5 shows a partial cross section along the line V-V of FIG Pig. 2,

Pig. 6 shows a partial cross section along the line VI-VI of Pig. 2,

Pig. 7 shows a partial cross section along the line VII-VII of the Pig. 2, and

Pig. 8 shows a partial cross-section along the line VIII-VIII in Pig, 2.

1 shows a hydraulic system with a pump 1, which

Pressurized fluid from a container 2 via a pressure line 3 ii & in control unit 4 supplies. To the control unit is by means of

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two working channels 5 and 6, a motor 7 is connected. Sine Drain line 8 connects the control unit via an aiP return filter 9 with the container 2.

A pressure relief valve 10, the pressure line, is provided in the control unit 5 and drain line 8 connects to each other and opens when a set pressure is exceeded.

In parallel, there is a volume control valve 11, which is controlled by the pressure drop is controlled on an adjustable measuring orifice 12. For this purpose the valve 11 is connected via two impulse lines 13 and 14 with the sections 8a and 8b of the drain line 8 in front of and behind the orifice plate 12 connected.

A changeover valve 15 is shown schematically. It has five main positions ae, into which it can be brought by external actuation, for example with the aid of a hand lever 16. A connection piece Ver _T c is in the neutral dividing the pressure line 3 with the aid 17 is connected to two working channels 5 and 6, while in the discharge line 8 is installed a lock 18th In the two active positions a and e, the pressure line 3 and the discharge line 8 are each connected to one of the two working channels 5 and 6. In the braking positions b and d, the pressure line 3 is connected to one of the two working channels 5 or 6, while a lock 19, 20 is provided in the drain line for the other line in each case. In the event that when the drain line 8 is blocked, an overpressure occurs in one of the working channels 5,6, each of these channels is assigned a pressure valve 21,22 which opens at a predetermined overpressure and pressurized fluid through a line 23 into the drain line 8 behind the Orifice 12 conducts.

The measuring aperture 12 is on the one hand via a mechanical coupling 24 - with the movable part of the Umachaltventils 15 in connection

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and is therefore also adjusted when the hand lever 16 is moved In addition, acts on the orifice plate via a pulse line 25 of the Inlet pressure in the pressure line 3. Finally, the measuring orifice 12 also forms the locks 18, 19 and 20 in the neutral position c and the two braking positions b and d & es changeover valve 15.

This circuit results in the following mode of operation

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The two working channels 5 and 6 are in the neutral position connected with each other. The motor 7 can therefore work in freewheeling mode The measuring orifice 12 holds the drain line 8 closed as a lock 18. The entire liquid delivered by the pump 1 flows Via the volume control valve 11, which is forcibly opened in this state, or via the overpressure valve 10.

In the two active switch positions a and e, the The amount of liquid delivered by the pump through the flow control valve 11 split; the rest flows through the engine. The open position of the flow control valve 11 is determined by the pressure drop across the Orifice 12 controlled through which all the liquid flowing through the engine flows. The further the lever 16 in sighting is moved to one of its end positions, the more it opens Measuring orifice 12 and the less liquid flows past the motor via flow regulator 11. The cross-sectional enlargement of the measuring orifice can take place linearly with the creation of the switching valve. When the engine 7 is more heavily loaded and therefore the If the pressure in the line 3 rises, then the impulse line 25 will open an even greater opening of the measuring orifice 12 around the inner To compensate for leakage oil losses of the engine.

In the brake positions b and d is one side of the engine awar still under pressure from the pump _1%, but the other side is closed by the locks 19 _f 20th As a result, the engine brakes. If the pressure increase is too great, liquid can flow into the discharge line 8 via the pressure relief valve 21, 22, bypassing the measuring orifice 12.

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In the illustrated embodiment example, the neutral position is c is limited to an angle of rotation of 3 ° on both sides of the Hull line, the next 0.5 ° corresponds to the braking position. A further turn up to 20 ° gradually leads to the complete opening of the measuring orifice 12.

Reference is now made to the embodiment of FIGS. 2-7 taken. In these figures, the pressure relief valve 10 is that as well is housed in the control unit 4 cannot be seen.

In a housing 26, thereby closing a cover 27, there is a hole in which several sleeves are arranged concentrically one inside the other. The first sleeve 28 is "non-rotatably" however arranged to be axially displaceable. For this purpose, a pin 29 engages, which is eccentrically attached to a nut 30 provided with an adjusting nut Screw 31 is attached and provided with an elastic ring 32, in a corresponding recess of this sleeve. A second Sleeve 33 is axially fixed between the cover 27 and a holder 34, but can be rotated, for which purpose a toothing 35 is provided for the insertion of a toothed shaft. A third sleeve 36 is axial, through a spring ring 37 and a Contact edge 38 is fixed on the second sleeve 33. It can rotate with the second sleeve, but does not need to. Its fourth Sleeve 39 or a piston is by a spring 40, which is supported on a plate 41 near the toothing 35, against a Snap ring 42 pressed. It can move axially until a pin 43 strikes the plate 41.

In a transverse bore 44 'which is closed by a plug 45, there are two under the influence of a spring 46 Balls 47,48, which correspond to the pressure relief valves 21,22.

In the area of the first sleeve 28 there are four annular spaces. The right annulus 49 is with the connecting piece 50 for

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Pressure line, the left annular space 51 with the connection piece 52 for the drainage line in connection. The two middle annular spaces 53 and 54 go to the connecting pieces 55 and 56 for the Working channels. Three each evenly distributed over the circumference Openings 57, 58 and 59 connect the annular spaces 49, 54 and 53 with the inner circumference of the first sleeve 28.

In the second sleeve there are three shorter longitudinal grooves 60 and three longer longitudinal grooves 61 between them. The shorter longitudinal grooves 60 can connect the openings 57 to the openings 58 or 59. The longer longitudinal grooves 61 have the same puncture, but extend beyond that into the annular space 51. There they are covered by extensions 62 on the first sleeve 28 to a greater or lesser extent. Also lead from the shorter longitudinal grooves 60 breakthroughs 63 to the inside of the second sleeve 33, while 61 openings 64 lead from the longer longitudinal grooves to the inner circumference. As an extension of the shorter longitudinal grooves, through » breaks 65 are provided, which connect the interior 66 of the bore with the annular space 51.

In the third sleeve 36, in the area of the openings 63, there is an annular space 67 with openings 68 and in the area of the openings 64, an annular space 69 with openings 70. Furthermore, openings 71 are provided on the left side, which extend to the Open interior 66.

The piston 39 has an elongated annular space 72, which at a. Axial displacement of the sleeve 39 to the left connects the openings 68 with the openings 71 in the third sleeve 36.

The first sleeve 28 has a slightly larger diameter in its right area 73 than in its left area. It is therefore pressed to the right by the pressure prevailing in the annular space 4-9, the axial displacement being dependent on the restoring force of the elastic bing 32.

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The pressure in the longer longitudinal groove 61 prevails in the space 74 on the right of the piston 39, because this space is connected to this groove via the openings 64 »the annular space 69 and the openings 70. In the space 66, the pressure prevails in the annular space 51 because it is connected to it via the openings 65. As a result, the piston 39 is under the influence of the pressure drop at the orifice plate, which is formed by the longitudinal groove 61 and the port set 62. As a result, the piston 39 moves a corresponding distance to the left against the force of the spring 40 and the annular space 72 opens find out about one more or who! ger large piece of the breakthroughs 71 · the annular space 72 and the breakthroughs 71 form the flow control valve, which via the breakthroughs 68 »the annular space 67» the breakthroughs 63 »the shorter longitudinal grooves 60» the breakthroughs 57 and the annular space ₁ 49 with the pressure line connector 50 and is connected to the drain line connector 52 via the interior 66, the openings 65 and the annular space 51.

Like Pig. 3 shows, by rotating the second sleeve 33, the cross section of the longitudinal groove 61 becomes linear under the extension 62 released. As a result, the orifice plate opens linearly with the rotation. Since the extension 62 has a greater width than the groove 61 »opens only after the neutral position is already abandoned. By turning the screw 31, the first sleeve 28 can be displaced axially. As a result, that will The end of the longitudinal groove 61 is more axially covered (right side of FIG. 3) or less (left side of FIG. 3). Therefore, by adjusting the screw 31, the measuring orifice can be adapted to the maximum flow cross-section of the connected working machine will. It can be seen that this does not disturb the linearity when the aperture is enlarged. Also will depending on the size of the inlet pressure - as already mentioned - the outer sleeve 28 is axially displaced against the restoring force of the elastic ring 32 »so that a change in the aperture can also result as a function of this.

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ORIGINAL

The Pig. 2 to 7 show a position which may correspond to the clockwise rotation of the motor and which corresponds to position 15a of the switching valve. In this state, pressure fluid flows in via the nozzle 50 and reaches the working channel 5 of the Hotor3 via the annular space 49, the openings 57, the short longitudinal groove 60, the openings 58, the annular space 54 and the nozzle 56. Tom Motor, the liquid flows through the channel 6 to the connection piece 55, further through the annular space 53, the breakthrough 59, the longer longitudinal groove 61, the orifice plate, the annular space 51 and the connecting piece 52 to the drain line. A pressure drop occurs at the diaphragm, as a function of which the piston 39 moves to the left and the pressure control valve 72, 71 opens more or less, as a result of which part of the pumped liquid is bypassed the motor. In this way, an approximately constant flow of liquid is maintained through the motor. Its size can be changed by rotating the second sleeve 33. The same applies to counterclockwise rotation when the pressure fluid does not flow on from the shorter longitudinal groove 60 via openings 58, but rather via openings 59 to the annular groove 53.

If the second sleeve 33 is rotated towards the neutral position, so, shortly before the switchover opening, that is, the connection of the longitudinal grooves 60,61 with the openings 58,59, is rendered ineffective willy. prepare the left end of the longitudinal grooves 61 through the extensions 62 completely covered. This means that no more liquid can flow off to the engine via the normal T7i »g. The engine will thus braked. The liquid can then only come under from the annular spaces 53 or 54 via the associated pressure relief valves 47 and 48, respectively Bypass the measuring orifice 61,62 into the transverse bore 44 and from there to drain line 8.

The two working duct connections are in the neutral position itself 55f66 directly related to each other because the

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Openings 58 and 59 connect the associated annular spaces 53 and 54 to two adjacent grooves 60 and 61, respectively. Equilateral however, the connection of the shorter longitudinal groove 60 with the pressure line connector 50 remains. The engine can therefore rotate in freewheel; the motor system is with the pump pressure line tied together.

But since the pump pressure also prevails in the longer longitudinal groove 61, If this pressure spreads also in the space 74-, whereby the piston 39 pushed all the way to the left and therefore the volume control valve 72, 71 is fully opened.

A neutral position spring consisting of four spring biafcers 75 76 is supported both on the first sleeve 28 and on the second sleeve 33 in the rest position. If the second sleeve 33 is rotated, the spring leaves 75 are tensioned and leave the second sleeve in the rest position again when the rotation is complete to return"

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Claims (16)

-1E2ÄU9- Claims; ( 1J Hydraulic system with a hydraulic motor, with a four-way switch valve, which has a pressure line, a drain line and two working channels leading to the motor, which are in two active switch positions on both sides of a neutral position via switchover openings with the Pressure and discharge lines are connected, and with a flow control valve connected in parallel to the switching valve, which is controlled as a function of the pressure drop at an adjustable measuring orifice through which the liquid flowing through the motor flows, characterized in that the adjustable part of the measuring orifice (• 12 ) is connected to the adjustable part of the switching valve (15) and the flow control valve (11) is arranged in the switching valve (15). 2. Plant according to claim 4, characterized in that the adjustable The measuring orifice (12) is in the discharge line (8). 3 · Plant according to claim 1 or 2, characterized in that the Orifice plate (12) in the one directly adjacent to the neutral position Part of the two active positions is fully closed. 4. Plant according to claim 3 »characterized in that the two working channels (5» 6) are connected to one another in the neutral position are. 5. Plant according to one of claims 1 to 4, characterized in that the two working channels (5, 6) each have a pressure relief valve (21, 22) with the discharge line (8) behind the measuring orifice ·. (12) are connected. ■■ - documents ' BATH 109810/0043 -H- 6. Plant according to one of claims 1 to 5, characterized that the Heßblende (12) is influenced by the singing pressure in such a way, that it enlarges its opening with increasing pressure. 7. Plant according to one of claims 1 to 6, characterized in that that the switching valve (15) has two concentric and relatively rotatable sleeves (28,33), of which one opening (61) and the other one corresponding to the opening in the circumferential direction to form the EIeßblende Has cover (62). 8. Plant according to claim 7, characterized in that the cover (62) is somewhat wider in the circumferential direction than the opening (61). 9. Plant according to claim 7 or 8, characterized in that the a sleeve (33) with surrounding openings (58,59) of the other sleeve (28) has cooperating longitudinal grooves (6O, 61), and the Opening of the measuring orifice by extending at least one lengthwise groove (61) is formed. 10. Plant according to one of claims 1 to 9 »characterized in that that in the interior of the sleeve (28, 33) there is a piston (39) which is axially displaceable against spring force and whose end faces are acted upon by the pressure on both sides of the vent diaphragm (61,62) and together with an axially held part (36) form the flow control valve (71,72). 11.Anlage according to claim 10, characterized in that the with the measuring orifice connected longitudinal grooves (61) extend beyond the piston (39) and over a transverse channel (64 69,70) with are connected to the end face space (74) on the other side of the piston. 109810/0043 1828119 12. Plant according to claim 11 »characterized in that the with of the MeQbIende connected longitudinal grooves (61) in the neutralst The Lung are connected to the pressure line (3). 13 · Plant according to one of claims 1 to 12, characterized in that that the free opening cross-section of the Heßblende (61,62) increases steadily with the angle of rotation and that the outer sleeve (28) of the switching valve can be adjusted axially and thus the maximum free opening cross-section of the measuring orifice. 14. Plant according to claim 13 »characterized in that the adjustment organ of the outer sleeve (28) is an eccentric (29). 15 · Plant according to one of claims 1 to 14, characterized in that that the outer sleeve (28) in the area of the hanging canal (49) » which is connected to the pressure line (3), an increase in diameter has, and that an elastic element (32) is connected between the adjusting member (29) and the sleeve (28). 16. Plant according to claim 14 and 15 »characterized in that an eccentric pin (29) of the adjusting member elastic ring (32) is placed. 109810/0049