DE1051643B - Pressure control for hydraulic pumps or gears - Google Patents

Description

GERMAN

It is known to provide hydraulic pressure pumps with a pressure regulator iu, which can be influenced by the promotion of the usually variable Circulation speed driven pump «a certain exactly or somewhat unchangeable Maintains pressure in the pressure line, as far as this is compatible with the given delivery rate of the Pump is compatible. There are also known designs in which this oil pressure is still due to others Laws are co-determined.

As a rule, these are hydraulic pumps, in which the delivery rate is increased by changing the stroke the working piston is affected. The simplest form of such a pressure regulator is now! ”a pressure cylinder connected to the pressure line, which when the desired pressures * rain spring or weight action sets itself in motion iuid thus the pump adjusts to a lower delivery rate. Conversely, the pump is opened by this known device Increased delivery rate is set when the spring or weight forces exceed the force of the on the pressure line connected oil pressure cylinder predominate.

Egg is now known and almost always common, this simple pressure regulator with a pilot operated Replace pressure regulator. The reason for this is to be found in the fact that the attachment of a sufficient powerful spring especially since Itel the bigger one Puntpcnelnheitot encounters difficulties. That is to say the pressure isn't too much of what you want Value differ, then the force of this spring compared to the real movement resistance the pump adjustment must be chosen rather large.

Of the corresponding taxation, the most popular one is one in which a Kind of safety valve, consisting of a spring-loaded valve cone, pressure oil from the pressure line tapped as soon as the desired pressure has been created.

With this preferred pressure regulator, the resistance of the pumps has no direct or at least no significant influence on the oil pressure supplied by the pump, even if it takes up a nightly part of the spring or weight force or even if it takes up a part of the performance of the hydraulic servomotor introduced here. Since the above-mentioned safety valve can also be set up in the usual design from cone valve #> so that its opening or closing with sufficient genanijjkcit depends on the oil pressure in the pressure line and is little or not at all influenced by the counter pressure that the hydraulic actuating cylinder is subjected to .

With this design, therefore, there was no difficulty in using appropriate springs or weights

Pressure control for hydraulic
Pumps or gears

Applicant:

Dr.-Ing. Hans Thoma,
Grünwald near Munich,
Gabriel-von-Seidl-Str. 56

Dr.-Ing. Hans Thoma, Grünwald be! Münchea,
Has been called the inventor

In order to achieve the necessary performance of the hydraulic servo motor that drives the pump, all the more so as one is not dependent on the type of construction for which the spring or weight effect is exclusively the setting of the pump to a higher flow rate when choosing the servo motor accomplish. In this hydraulic pump system with pressure control, which is designed in a known or obvious manner with hydraulic pilot control, it is therefore easily possible to

Jo stungsstarkkcjt the servo motor and in particular the useful boy to be realized by the servomotor plenty to choose from. As a result, it is particularly easy here, according to the invention by one of This servomotor caused the adjustment movement

U also set the pump to reverse flow, * even more so than most hydraulic ones Pumping stations is easily possible and in some cases actually to prevent a too high oil pressure from other sources

to originate, it becomes necessary, from the pressure line Draw off pressure oil.

Fig. 1 shows an embodiment of the invention. P is the principle or the oil pump, which is usually from the shaft W in the usual manner

«S is driven at a constant speed. Here, this primary part is indicated as an axial directional cylinder with transparent cylinders, although this is not essential for the installation and any type of controllable pumping mechanism can be used, including those with variable piston stroke. By means of the spring F., which can also be replaced by a weight, the pump F is swiveled out and set to its maximum stroke approximately as far as the stop A , provided the system is at a standstill or not

1 * »» 7.311

there is sufficient oil pressure. This has the consequence that when the drive motor starts up , which sets the shaft W in rotation, the pump P immediately sucks in oil from the oil container and conveys it into the pressure line D , which leads to the control device St and the secondary part Se , this being the case mostly on the one hand a slide, on the other hand a pressure cylinder or a rotating oil motor. From the control member St z. B. the return line R in the oil tank, back.

As soon as the shaft W is set in rotation, the pressure line D is brought under pressure and the control device St can then be used in the known manner to actuate the secondary part Se . In order to regulate the pressure of the pump P ₁ when there is little oil withdrawal, which usually occurs when the control element St is in the middle position, a simple reset cylinder is not present in the known manner, which is directly connected to the pressure line D in a known manner P resets when sufficient pressure arises, but the actuating cylinder Ss is in turn only controlled via a pilot valve V. In the simplest version shown in Fig. 1, this consists of a spring f, which has a valve body K, which acts as a piston or valve cone - as is usual with safety valves - can be carried out so loaded that it is only raised at a certain oil pressure and pressurized oil can flow out of the line D into the pressure control line d . This pressure line d is in connection with the control cylinder Sz and thus causes the pump P to be reset only when the correct oil pressure has arisen in the pressure line D , as is required to raise the pilot piston K in the pilot valve V.

Compared to the direct actuation of the pump P by a control cylinder hanging on the pressure line D , this device has the advantage that any type of resistance to movement on the actuating device of the pump P has no direct or greater influence on the pressure setting of the pumping mechanism, since the pilot piston K with the appropriate device is mainly actuated only by the pressure in the pressure line D and the spring tension f , so that its control function can take place without any major dependence on the resistance to movement of the actuating tool to the pump P. It is therefore possible to make the control cylinder Sz relatively small without prejudice to the good effect of the pressure control, as is the spring f, since the force development thereof no longer has any direct influence on the pressure setting of the pump P in this arrangement according to the invention.

The indirect actuation of the pump P by the servomotor makes it possible without further ado to select its stroke to be sufficiently large, so that, if necessary, the pump can also be driven through the zero position, which is caused by the coincidence of the dash-dotted pump axis

ίο is marked with the horizontal line W , can be lifted out, which in most pumping stations a reverse delivery is achieved, so that now excess oil can be removed from the pressure line d . Therefore, even when such excess oil pressure occurs, it is no longer necessary to provide special safety valves for this purpose, but the servo-motor device, which allows the pump to be set to reverse pumping, at the same time enables excess oil to be absorbed, as in some cases in some systems becomes necessary.

The details of the design of the servomotor are immaterial. For example, servomotors can also be used are used, which in the mutual sense of motion by hydraulic forces, if necessary in connection with spring and weight effectively, be set in motion. The arrangement is essential a pressure control in connection with the associated servo motors, so that the hydraulic If necessary, the pump can also be set to run in reverse.

Claim:

For the controllable pump of a hydraulic Transmission certain ^ regulating device, which with With the help of a servo motor, the pump as a function of the delivery pressure against the action of a Adjusts a spring or a weight, with a pilot valve switched into a removal line which starts from the pump delivery line and leads to the servo motor, characterized in that that the pump can also be set for reverse pumping by a pivoting movement caused by the servomotor.

Considered publications:
German Patent No. 736 166;
U.S. Patent No. 2,284,897.

1 sheet of drawings

797/311 2.59

Claims (1)

there is sufficient oil pressure. This has the result that during startup of the drive motor, wherein the shaft W set in rotation, the pump P immediately draws oil from the oil reservoir east and promotes in the pressure conduit D which leads to the control device St and the secondary part Se, and this most on the one hand a slide, on the other hand a pressure cylinder or a rotating oil motor. From the control member St z. B. the return line R back into the oil tank. Therefore, as soon as one is the wave W in circulation, the pressure pipe D is brought under pressure and the control device St can then in the known manner for actuating the secondary part ^ g bgnutzt expectant en ^ To now at low oil extraction, in particular, in the center position of the control member St usually occurs to accomplish the pressure control of the pump P , there is not a simple reset cylinder available in a known manner, which resets the actuating device of the pump P when the pressure is reached, directly connected to the pressure line D in a known manner, but the actuating cylinder Sz is in turn only controlled by a pilot valve V. In the simplest version shown in Fig. 1, this consists of a spring f, which loads a valve body K, which can be designed as a piston or valve cone - as is usual with safety valves - so that it is only raised at a certain oil pressure and pressurized oil from line D i n allows the pressure control line d to flow out. This pressure line d is in connection with the control cylinder Sz and thus causes the pump P to be reset only when the correct oil pressure has arisen in the pressure line D , as is required for lifting the control piston K in the pilot valve V. Compared to the direct actuation of the pump P by a control cylinder hanging on the pressure line D , this device has the advantage that any type of resistance to movement on the actuating device of the pump P has no direct or greater influence on the pressure setting of the pumping mechanism, since the pilot piston K with the appropriate device is mainly operated only by the pressure in the pressure line D and the spring tension f , so that its S expensive function can go on without major dependence on the resistance to movement of the actuating tool to the pump P. It is therefore possible to make the control cylinder Sz relatively small without prejudice to the good effect of the pressure control, as is the spring f, since the force development thereof no longer has any direct influence on the pressure setting of the pump P in this arrangement according to the invention. The indirect actuation of the pump P by the servomotor makes it possible without further ado to select its stroke to be sufficiently large, so that, if necessary, the pump can also be driven through the zero position, which is caused by the coincidence of the dash-dotted pump axis ίο is marked with the horizontal line W , can be lifted out, which in most pumping stations a reverse delivery is achieved, so that now excess oil can be removed from the pressure line d . Therefore, even when such excess oil pressure occurs, it is no longer necessary to provide special safety valves for this purpose, but the servomotor device, which allows the pump to be set to reverse pumping, at the same time enables excess oil to be absorbed, as in some cases in some systems becomes necessary. '■■ ·· - The details of the design of the servomotor are immaterial. For example, servo a5 motors are used, which are in mutual Sense of movement of hydraulic forces, given? if in connection with the action of the spring and weight, set in motion. The arrangement is essential a pressure control in connection with the associated servo motors, so that the hydraulic If necessary, the pump can also be set to run in reverse. Claim: Control device intended for the controllable pump of a hydraulic transmission, which with With the help of a servo motor, the pump as a function of the delivery pressure against the action of a Adjusts a spring or a weight, with a pilot valve switched into a removal line which starts from the pump delivery line and leads to the servo motor, characterized in that that the pump can also be set for reverse pumping by a pivoting movement caused by the servomotor. Considered publications:
German Patent No. 736 166;
U.S. Patent No. 2,284,897. 1 sheet of drawings ® 809 767/311 2.59