SE415390B - LOAD-COMPENSATED HYDROSTATIC POWER TRANSMISSION SYSTEM - Google Patents

Description

7713038-3 __ 2 _ total system, which meets the requirements for occupational safety ooh ergonomiw with less power losses than before and which can be connected to rauliska_arbetsmaskiner.

For the hydrostatic power transmission system according to the invention it is essentially characteristic that when one or more drive devices load situation of mechanisms or mechanisms due to it with control impulse determines the load and / or speed of movement requires higher pressure of the printing medium and / or greater supply of pressure medium than that present in the hydraulic circuit in question, from such a hydraulic drive device or mechanism corresponding directional valve connection --- when the control pressure of the valve reached or exceeded one for this purpose regulated for the purpose or set value --- from valve pressure line or channel to a power demand line leading to the hydraulic guide or mechanism that controls the function or position of the drive motor orbital regulatory body of the Kosovo Power Transmission .the system, the system itself automatically as a result of the The load situation transmits along the said power demand line a power balance impulse, to by conveying said hydraulic steering means or mechanism and regulating the drive motor speed the body to provide the required level of regulation of the drive motor and that in a hydrostatic power transmission system with multiple The puppet drive motor speed has been arranged to be determined according to it pump circuit, in which the hydraulic pump requires the largest speed ooh whereby excess power of other pumps is prevented by means of power balance impulse control of each pump.

The distinguishing feature of the system, then, is that the control pulse is routed to the directional valve of the mechanism, where comparison is made between desired and occurring state of motion. Insofar as any difference between these e- exists, a control pulse emanates from the directional valve along the power the lance impulse line to the drive motor, e.g. the injection pump on a diesel engine, which regulates the engine speed to the required size play.

The hydraulic pumps belonging to the system are control pumps, which in The normal operating situation works with a maximum of fl a.regulation angles, var- 'at the drive motor speed are as low as possible. For the pumps: control devices include a maximum power control unit, which overloads drive motor torque is prevented. To the control devices also includes limiting the maximum pressure of the hydraulics. In addition, pumps pairs control of the control angle on the basis of power balance impulse. 7713038-3 _3_ This control was used to reduce the power, in case of operating the number of races is currently too large or several pumps are present in the system. In a multi-pump system, the speed of the drive motor is determined the pump circuit that requires the largest revolutions. Overeffectiveness of pumps are prevented by means of power balance impulse control of each je pup separately. In this case, the deti.den English pump does not cause pen required high speed overpower or power losses in other pumps.

. In the system according to the invention, the efficiency increases significantly higher than in current systems and also improves the energy of the drive motor balance due to correct turnover figures. When an internal combustion engine is used used as a drive motor, it drops in the operating situation lower than normal added significantly when examining the level of interference, especially through noise measurements.

"The ergonomic advantage of the system according to the invention can be considered to be, except that the control devices are light, that simultaneous adjustments are independent of each other. Currently, the operator must follow the end result of 4 - 5 separate interacting regulatory situations and uninterrupted right to individual regulatory impulses when the load situation changes. The system according to the invention hydrostatic power transmission plant does what is required of it, without the operator constantly examining whether the desired situation realized.

The invention appears in more detail from the following description and is attached drawings, in which Fig. 1 shows a circuit diagram for the invention according to the invention. compensated hydrostatic power transmission system, Fig. 2 shows a diagram of the mutual regulation of the main components effects in the system, 'i Fig. 3 shows a diagram of a hydraulically controlled directional valve group equipped with power control line and Fig. 4 shows a working sketch of the counter-valves for a direction of movement individual directional valve in the directional valve group according to gur 3 .. Since a very substantial part of the load according to the invention compensated hydrostatic power transmission system consists of for purpose-directed directional valves of a certain type, it is reasonable to first clarify the design principle of such a valve.

As Figure 3 shows, the directional valve consists of two between them , 771zozs-z _ 4 _ identical work units, thereby creating movements in each direction ningen e.g. of piston 5141 a double-acting cylinder piston device 48, with one unit in one direction and with the other unit in the opposite direction. take the direction. Figure 4 relates precisely to the design principle for such a work unit in a directional valve. To the work unit hear two spindle-guided spindles 1 and 2. Each of the spindle 1 and 2 to the left of the drawing located the delimiting spaces 7 and 8 communicate with the tank line via connections 9 and 10.

The space 11 adjacent to the right of the spindle 1 in the drawing is arranged to be combined with the control pressure line. That to the spider 2 in the drawing right end adjacent the room 12 stands by mediation of the transfer channel 13 in connection with that in the borehole for the control of the part 1 formed the annulus 14 and via this further end of the position of the spindle 1, either along that inside the spindle 1 continuous duct line 15 with the space 7 and from here with the tank line or from the annulus 14 directly with the guide pressure chamber 11 of the spindle 1.

As shown in Figure 4, the center point 16 of the spindle 1 constitutes the spindle 1 narrowest place and at this place around the spindle 1 an opening opens channel 4. To the left of the channel 4 in the drawing is a channel 3 and between in channels 3 and 4 in the valve body there is a seat socket 17. It with the seat cooperating member of the seat housing 17 is one from the spindle 1 to the sides projecting annular flange 18. The spindle 1 to the left in the drawing The end 19 is guided through an intermediate cavity 20 and around the spindle 1 between the intermediate cavity 20 and the annular flange 18 of the spindle 1 is arranged a coil spring 21, which strives to push the spindle 1 in the direction towards the control pressure chamber 11 and thus to the right in the drawing. Venti- The pressure limiting part of the lens consists of a cavity 22, which in this construction option is located on top of the pressure reducing spindle 1 and the The pressure relief cavity 22 is pressed (to the right in the drawing). ) of a coil spring 23 arranged around it for flow current mode. The inner diameter of the pressure relief sleeve 22 is at its right end greater than the width of the socket 22 corresponding to the intermediate cavity outer surface of the kens 20, so that a ring surface 24 arises which can be affected by the pressure in the intermediate space delimited by the socket 22, the spindle 1 and the seat 17 the opening direction of the pressure relief valve. In addition, the cavity 22 of the pressure relief part at the space 25 provided with made flow traces or equivalent means (not shown in the drawing) so that when the radiating pressure in the space 25 presses the socket-22 in the opening direction, at a given pressure 1 the space 25 arises a leading opening from the gap 25 to the channel 3 surface area, which together with the pressure value determines the flow rate. _ 5 _ _ 77130384 Those in connection with the connection of the spindle 1 or with the channel 4 the pressure surfaces of the spindle 1 are equal in both directions, why the pressure acting in the channel 4 does not affect the spindle 1 movements. The control pressure and the force it gives rise to the the surface of the end of the spindle 1 is counteracted by the pressure of the gap 25 on it pressure surface formed in the gap 25 due to the difference in diameter the meters on the annular flange 18 of the spindle 1 and the end 19 of the spindle 1.

The spindle 1 is a pressure reducing spindle with four essential pressure areas. A1 = pressure surface of the control pressure, A2 = tank pressure surface, A3 = intermediate mets pressure surface and A4 = compensation pressure surface for the return line print. ' The surface ratio A1: A3 determines the magnitude of the pressure in the gap 25 at a given value of the control pressure, in the case of the return pension is not taken into account. For example, at a surface ratio of 4: 1 a quadruple pressure occurs in the space 25 compared to the control pressure. ket. In case this pressure tends to grow, the power of the spindle 1 equilibrates the spindle 1 against the control pressure and closes the connection between channel 4 and the gap 25. In case of pressure there is in the return line 3, the pressure value of the gap 25 should be increased by the value of the back pressure, in order for the desired pressure difference for the pressure relief valve to be stand. This is so arranged that from the channel 3 leads a connection kanalbâšäšåålhâfšešíššutrymme 2? between it around the right of the spider 1 spirit and the spindle 1. The box 28 is so designed that its inner surface 30 diameter to the left of the annulus 27 is larger than its inner surface 29 diameter to the right of the annulus 27. Spindle 1 diameters on each side of the annulus 27 corresponds to the diameters of the housing 28 surfaces 30 and 29 as shown in Figure 4. Thus occurs on spin- part 1 in the annulus 27 a compensating pressure surface A4, which to the area dimensioned as large as the pressure surface A3 of the gap 25. Here- at, the pressure value of the gap 25 increases with the size of the return line 3 pressure value and for the flow rate regulating pressure limit a pressure difference corresponding to the control pressure and thus desired volume flow.

In the part comprising the spindle 2, the arrangement is very similar to the the arrangement at the spindle 1. 2 As shown in Figure 4, the center point 31 of the spindle 2 constitutes the spindle 2 narrowest place and in this place around the spindle 2 an opening opens channel 6. To the left of the channel 6 in the drawing is a channel 5 and in the channels 5 and 6 in the valve body there is a seat clamp 32. It with the seat surface cooperating member is one from the spindle 2 '7713-038-3 _ 6 _ The sides of the spindle protruding from the sides 33. The spindle 2 on the left in the drawing The end 34 is guided through an intermediate cavity 35 and around the spindle 2 between the intermediate cavity 35 and the annular flange 33 of the spindle 2 is attached. arranged a coil spring 36, which strives to push the spindle 2 in the direction towards the space 12 adjacent to the end of the spindle 2 and thus ate right in the drawing. The pressure limiting part of the valve consists of a socket 37, which is located on top of the pressure reducing spindle 2 and the intermediate cavity 35.7The pressure relief sleeve 37 is pressed (to the right of the drawing) by a around this arranged coil spring 38 to flow closing position.

The inner diameter of the pressure relief sleeve 37 is at its right end larger than the width of the hollow corresponding to the outer surface of the intermediate housing, so that a ring surface 39 arises which can be affected by the pressure in it off the socket 37, the spindle 2 and the seat 32 delimited the space 40 in pressure relief valve opening direction. In addition, pressure the cavity 37 of the boundary member at the gap 40 provided with shaped flow track or equivalent means (not shown in the drawing) so, that when the pressure prevailing in the gap 40 presses the housing 37 in the opening direction occurs at a given pressure in the gap 40 a ~ given end from the gap 40 to the channel 5 leading opening surface area, which together with the pressure value determines the flow rate.

Those in connection with the spindle are owned 2 connection or the channel 6 standing the pressure surfaces of the spindle 2 are equal in both directions, why the pressure acting in the channel 6 does not affect the movement of the spindle 2 looks. The pressure in the chamber 12 and the force it gives rise to the pressure the surface of the end of the spindle 2 is counteracted by the pressure of the gap 40 on it pressure surface formed in the gap 40 due to the difference in diameter meters on the annular flange 33 of the spindle 2 and the end 34 of the spindle 2.

Analogous to the stated pressure compensation in connection with the spindle 1 has in connection with the spider 2 the situation has been arranged correspondingly, by leading a connecting channel 41 to an annulus 42 therebetween around the right end existing cavity 43 of the spindle 2 and the spindle 2.

The socket 43 is designed so that its inner surface 45 has a diameter of if the annulus 42 is larger than the diameter of its inner surface 44 to the right of the annulus 42. The 2 diameters of the spindle on each side if the annulus 42 corresponds to the diameters of the surfaces 45 and 44 as shown in Figure 4. Thus also occurs on the spindle 2ii the compensating pressure surface 42, which is dimensioned to the area equal to the pressure surface of the gap 40. In doing so, the the pressure value of the space 40 with the magnitude of the pressure value of the return line 5 and for the flow rate regulating pressure relief valve is a pressure difference corresponding to the control pressure and thus desired _ 7 _ 771.3038-3 volume flow.

The part comprising the spindle 2 also opens into the cavity 43 surface part 45 a channel 46, in which a counter-valve 47 is provided which allows flow away from the spindle 2, but prevents flow towards spindle 2. When the pressure prevailing in the room 12 is high enough, the spindle 2 moves to the left and the annulus 42 in this when channel 46, opening connection from channel 5 via connection channel 41 to channel 46.

The function of the directional valve is described below with reference to Figures 3 and 4. Each directional valve thus consists of four pressure compensated flow control valves, which are channeled together in in accordance with the schematic representation in Figure 3.

The main purpose of the directional valve is to achieve the desired movement. direction and speed of mechanisms connected to it, independently of whether the plant has been subjected to a positive or negative load. _ In addition, the directional valve according to the application has a power balance impulse line, with which the necessary oil coming from the control pump the amount of the mechanism is regulated. To illustrate the working method description, a cylinder piston device 48 is connected to the valve.

If desired the piston 51 and piston rod of the cylinder piston device48 52 should move to the left and thus the pressure oil flow from the to the chamber 50 of the cylinder piston device 48 and return from the chamber 49 of the cylinder piston device 48 via the channel 4 to the tank line, the control pressure is directed to the control pressure chamber 11 towards the end of the counter spindle 1, line OB3 in Figure 3. In case the load is negative tiv or the load itself produces the desired movement, it is sufficient with the control pressure of the chamber 11 opening the connection from the channel 4 to channel 3, the pressure medium leaving the cylinder piston device 48 room 49 via the space 25 of the channel 4 and the channel 3 for entering the tank line. The filling of the space 50 on the cylinder of the cylinder piston 48 the other side is done via a suction valve --- a non-return valve, which is free flow from the tank line to the channel 5, but impedes the flow in the opposite direction --- directly from the tank line. In case of positive or the force action of the load is opposite to the desired increased direction of movement, the normal of the counter-valve spindle 1 is not sufficient opening movement to, but the steering pressure should be increased so that the spindle 1 moves until the control pressure from the space 11 can enter the transfer the channel 13 and via this in it to the end of the counter valve spindle 2 adjacent space 12 on the pressure side, where the formed pressure opens in question counter-valve and connection from the pressure channel 6 to the nal 5 opens. In case the pump does not supply enough 7713038-3 pressure medium, override occurs: V spindle ë: on the pressure side “mdtven- til when the control pressure continues to increase and the spindle 2 is moved on due to the effect of the control pressure so much that the connection from via the connecting channel 41 to the channel 46 is opened, whereby all so connection occurs from the channel 5 to the power balance pulse line via the non-return valve 47. Using the power balance impulse line is affected the power of the control pump so that the amount of oil produced by the pump is sufficient for the mechanism or mechanisms.

If for the piston rod 52 of the cylinder piston device 48, it is desired in figure 3 with the direction of movement indicated by the arrow or that the piston rod 52 is pushed outwards, the control pressure of the directional valve is directed to the channel OA3. Here- at the counter valve VT joins the reciprocating device corresponding to the direction of movement. the side or chamber 50 on the same side of the piston rod 52 with the tank line.

The counter valve VT is volume regulating, which means that one with the pressure proportional oil flow can pass through it. In case of is negative or the load itself produces the desired motion then, it is sufficient that the counter valve VT opens and desired movement occurs. In this case, the filling of the other side 49 of the cylinder 48 takes place through SUG valve from the tank line. In case the load is positive and desired movement does not occur by joining the outlet side 50 medtnmæ channel, occurs due to the increased control pressure oversteer in in the counter valve VT which opens a channel on the inlet side 49 to it from pump coming pressure line via valve VP. This opens everything the control pressure OA3 valves VT and VP and the SUG valve are kept closed.

In case there is insufficient pressure in the pump line, alen VP override when the control pressure increases, of which, follows that the duct 33 on the sliding side 49 of the cylinder is combined with the so-called power balance impact line, the pressure occurring in the line regulating the pump power so that it is sufficient to effect the desired movement.

The directional valve of the directional valve leading to the tank channel includes always a flow rate regulating part, while in the counter valves on pressure side this is not always necessary.

Pressure control which takes place via the transmission channel 13 can also be replaced with a mechanical arrangement.

The actual object of this invention, a full load compensated hydrostatic power transmission system. In it- related to the pressure-compensated hydraulic power transmission a system in which the desired direction of movement and the speed of movement of the hydraulic mechanism is determined by control impulse and where the system itself on the basis of the load situation regulates the power and speed of the drive motor. 7713038-3 _ 9 _ The hydraulic diagram of the system is shown in Figure 1 in an application there the diesel engine 53 rotates two volume control hydraulic pumps 54 and 55.

Mechanisms 68 and 69 maintain the control angles of pumps 54 and 55 normal operating situation in position for maximum control angle and à others the diesel engine runs at the lowest possible speed. Pumps 54 and 55 circulates pressure oil in its hydraulic circuits in normal situations through the hydraulically controlled directional valves 70 and 71, as well as through mechanisms 68 and 69 and past throttle points 72 and 73 via the flow channel 74 to the tank 75, where again the pumps 54 and 55 gives pressure oil. From the hydraulic circuits the main flow lines lead 60 and 57 in accordance with Figure 1, wherein in each circuit by means of the valves 58 and 59 of the directional valve group belonging to the circuit the pressure oil flow from the main flow lines 60 and 61 to the the mechanisms connected to the system can be regulated so that in these of the mechanism determined by the control impulse of the valve 58, 59 direction and speed of movement. _- _ The load-compensated hydrostatic according to the invention characteristic of the power transmission system is that the control pulse to the directional valve 58, 59 of the mechanism, where comparison occurs father between the desired and occurring state of motion. In case of difference between where these exist departs from the directional valve 58 and / or 59 a control pulse through power balance fl pulse line 66 and / or 67 to the mechanical nism 65, which by means of a regulating means 64, for example the diesel engine's injection pump regulates the drive motor 53's circulation number am correspond to the full loading situation. The system thus regulates the automatically on the basis of the load situation 1 first dog drive tower speed using the power balance pulse line 66 and / or 67 to respond to the load situation. Between power demand lines- 66 and 67 and the tank is at the throttle point 76. In each line jen 66 and 67 there are also counter-valves 77 and 78, which allow flow of pressure oil only from the directional valve groups 56 and 57 in the direction of the mechanism 65.

One also joins the control devices of the pumps 54 and 55 maximum power control unit, thereby overloading the drive motor 53 torque is prevented. The control devices are connected to as a limitation of the maximum pressure of the hydraulics. For this purpose has in the main flow lines 60 and 61, pressure relief valves are provided. 62 and 63, which in the manner shown in the hydraulic diagram 1 figure 3 is connected to regulate the mechanisms 68 and 55 of the pumps 54 and 55 69. If, for example, according to the hydraulic system according to Figure 1 higher the power of the pump 54 is too great and the pressure 1 circuit

Claims (1)

7v13ozs-z _10_ then rises to the maximum pressure value of the pressure relief valve 62, the valve 62 opens and allows the pressure oil flow from the main flow line 60 to pass through. In the line between the valve 62 and the throttle point 72, the pressure rises and the mechanism 68 reduces the control angle of the pump 54 so that the power of the pump 54 becomes smaller. In addition to the above, the pumps 54 and 55 also have control of the control angle on the basis of power balance pulse. This control is used to reduce the power in case the operating speed is momentarily too large. Or several pumps are present in the system, whereby the excess power of the other pumps is thus prevented by means of the said power balance pulse control for each pump separately. The invention is of course not limited only to the above-mentioned application examples, but this can in many ways be varied within the scope of the claims. Claim-compensated hydrostatic power transmission system, where a drive motor (53), e.g. an internal combustion engine, drives one or more suitably volume-controlled hydraulic pumps (54, 55) and that each hydraulic pump (54, 55) is connected to its own hydraulic circuit, in order to supply pressure medium and provide the hydraulic pumps connected to the respective circuit. movements of the hydraulic drive devices or mechanisms and that the passage of the pressure medium in each of the said hydraulic circuits to the hydraulic drive devices or mechanisms is controlled by means of a hydraulically controlled directional valve group (56, 51) and that each hydraulic circuit also includes a suitable hydraulic pump (54, 55) and the directional valve group (56, 57) located, in the main flow line (60, 61) for pressure medium arranged pressure relief valve (62, 63) for limiting the maximum pressure of the circuit and that in normal operating situation each volume-controlled hydraulic pump (54, 55) is arranged to operate with its maximum control angle or maximum control volume value, while the speed of the drive motor (53) is as low as possible, due to the fact that when the loading situation of one or more drive devices or mechanisms due to the load and / or speed of movement determined by the control impulse requires higher pressure of the pressure medium and / or greater supply of pressure medium than occurs in the hydraulic circuit in question, opens from a directional valve (58, 59) corresponding to such a hydraulic drive device or mechanism --- when the control pressure of the valve (58, 59) has reached or exceeded a value regulated or set for this purpose, set or set for this purpose - from the pressure line or channel of the valve (55, 59) to a power demand line (66, 67) leading to the hydraulic control means or mechanism (65) which controls the function or position of the rotational speed of the drive motor (53) the means (64) in the hydrostatic power transmission system, the system itself automatically transmitting along said power demand line as a result of the resulting load situation (66, 67) a power balance pulse, in order to achieve, by means of said hydraulic control means or mechanism (65) and the rotational speed regulating means (64) of the drive motor (53), the required great control of the rotational speed of the drive motor (53) and that a hydrostatic power transmission system with several pumps the speed of the drive motor (53) is arranged to be determined according to the pump circuit in which the hydraulic pump (54, 55) requires the largest speed and excess power of other pumps (54, 55) is prevented by means of power balance impulse control of each pump for sig. MENTIONED PUBLICATIONS: