EP3242017B2 - Pressure intensifier for screw-in - Google Patents

Description

Subject of the invention

The invention relates to a preferably hydraulic pressure amplifier according to the preamble of claim 1.

A pressure intensifier is referred to here as a device that automatically produces a working fluid that is output at a higher pressure from a drive fluid available under low pressure, without an additional external drive. The details of such a device will be explained in more detail later.

Technical background

Such pressure amplifiers are used in many areas. The following areas of application are not exhaustive. For example, such pressure boosters are used to use low-pressure vehicle hydraulics to generate a high-pressure water jet for a cleaning device or to operate rescue scissors at high pressure to rescue passengers from accident vehicles. Such pressure amplifiers are also used in a variety of ways in industrial applications, for example to supply clamping tools or rotating chucks with the high pressure required for clamping. The clamping tools can be clamping tools used in industrial production or clamping tools used in assembly, and the rotating chucks can be part of a machine tool or, for example, a drill pipe for carrying out earth drilling.

The pressure amplifiers can be used individually or cascaded in series if a particularly high pressure is to be generated that cannot be achieved using a single pressure amplifier.

State of the art

The pressure amplifiers known in the prior art are typically connected via high-pressure hoses or hydraulic pipes to the hydraulic block, which supplies them with low-pressure hydraulic fluid and receives used hydraulic fluid. The connection to the high-pressure consumer, which is supplied with the increased pressure hydraulic fluid generated by the pressure booster, is also usually made via hydraulic hoses or pipes.

Connecting a pressure booster using high-pressure hoses or pipes to the hydraulic system supplying it and possibly also to the consumer it supplies is problematic. On the one hand, this is because hydraulic hoses can age over time and then tend to leak. Hydraulic pipes can fatigue over time, especially when subjected to oscillating loads. The connection with hydraulic hoses or pipes is also problematic where several pressure amplifiers are used, for example because they are cascaded in series. Space problems usually arise quite quickly and the system ultimately cannot be kept as compact as would actually be desirable. The use of hydraulic hoses in rotating systems, where the pressure amplifier also rotates, is particularly problematic.

The idea of flange-mounting a pressure booster directly to a hydraulic block, so that the outer surfaces of the pressure booster and the hydraulic block are pressed tightly against each other in one plane and fluid can be transferred without hoses, is also critical. Such flanges require considerable installation space in the transverse direction, a lot of screwing effort and also pose sealing problems at high pressures.

A pressure amplifier is known from the literature DE 196 33 258 C1 . Another known pressure booster has a coupling section for connection to a hydraulic block. It is held by an outer flange facing away from the coupling section with through holes through which it can be screwed to the hydraulic block using several through-bolts.

The problem underlying the invention

The invention is therefore based on the object of creating a pressure amplifier that can be connected to a hydraulic block without pipes or hoses and at the same time particularly reliably. This task is solved with the features of claim 1.

What is required is a pressure amplifier for fluids, in particular for liquids, which is generally ready for operation and only requires connection to a pressure supply, a tank connection and a consumer for the higher pressure it generates. The pressure amplifier therefore forms a ready-to-use unit that can be inserted completely or partially into a hydraulic block.

The pressure booster consists of a cylinder block in which a pressure booster piston and a control piston move cyclically. The control piston can assume different positions and thereby determines the working cycles of the pressure booster piston, whereby the control piston is not actuated by a mechanical forced control in the manner of a camshaft, but purely by a pressure difference. The pressure amplifier is designed in such a way that whenever it has reached a certain position, it initiates a change in the pressure conditions on the control piston so that it changes position.

The pressure booster piston is preferably designed as a differential piston with two differently sized, hydraulically effective piston surfaces; in any case, it forms a high-pressure working space and a low-pressure working space in the cylinder block. The pressure booster piston is usually solid, ie it preferably has no through holes that, for example, connect the high-pressure work space and the low-pressure work space with each other. Instead, the pressure booster piston usually has a constriction in the area of its circumference, which forms an intermediate space that lies between the high-pressure working space and the low-pressure working space.

The cylinder block has an external connection for feeding pressurized fluid from the outside, which is also called a low-pressure connection - because the pressure of the fluid here is lower than the pressure of the fluid delivered to the consumer by the pressure booster.

The fluid under said low pressure is intended to do work in the pressure amplifier and may also serve as a basis for generating and dispensing high-pressure fluid, i.e. a fluid that is under a higher pressure than the low-pressure fluid. In any case, the high-pressure fluid is delivered to the outside to an external consumer via an external high-pressure connection as working fluid under higher pressure.

Finally, the pressure amplifier has a connection for dispensing fluid whose working capacity has been exhausted in the pressure amplifier. This connection is also referred to below as the tank connection, even if it does not necessarily have to lead to a tank in the narrower sense. It should also be mentioned that the space in question usually forms part of a channel that leads to the tank connection.

The cylinder block of the pressure booster is here preferably understood to be a solid metallic body that contains all the cylinder bores and channels that are required for the pressure booster piston and the control piston to work together. In the majority of cases, the solid metallic body has cross-sections everywhere, at least in the area of the control piston and the pressure booster piston, in which the area that the solid material occupies in the cross-section is larger than the area that the cylinder bores and the channels occupy in the cross-section .

The cylinder block of the pressure booster has a coupling section rigidly connected to it. The coupling section is designed to be inserted into a receiving bore of a hydraulic block. It is designed in such a way that the receiving bore encloses the coupling section on its circumference and usually also on the front side. The coupling section has at least two fluid transfer areas that are fluidly separated from one another by a seal and are used to exchange fluid between the pressure booster and the hydraulic block in which it is inserted.

The fluid transfer areas are positioned on the coupling section so that they lie inside the hydraulic block into which the coupling section has been inserted, below the outer surface of the hydraulic block against which the part of the pressure intensifier not inserted into the hydraulic block abuts. As a rule, the fluid transfer areas are at least 20 mm, better at least 30 mm, below the surface of the hydraulic block.

This creates a particularly compact and reliable fluidic connection between the pressure booster and the hydraulic block of the machine that the pressure booster supplies. Because the fluid transfer areas are located far inside the hydraulic block and are therefore arranged in an extremely rigid area, a reliable seal can easily be achieved even under high pressure - even if disruptive factors such as vibrations are added.

The pressure amplifier is preferably designed in such a way that a channel opens into a fluid transfer area from the interior of the cylinder block of the pressure amplifier, via which the pressure amplifier releases fluid during operation, the working capacity of which can be used within the pressure amplifier has been exhausted. Another channel opens into a further fluid transfer area, also coming from the interior of the cylinder block. Low-pressure fluid is fed into the pressure amplifier via this channel, i.e. fluid that drives the pressure amplifier and possibly also forms the basis for generating fluid that is under higher pressure and is to be delivered to a consumer.

Ideally, the coupling section has a third fluid transfer area for transferring the working fluid under higher pressure to the hydraulic block. In this case, no pipes or hydraulic hoses are required to connect the pressure intensifier to its surroundings and thus make it ready for use. Instead, there is a direct hydraulic connection between the cylinder block of the pressure intensifier and the hydraulic block.

Ideally, at least one of the fluid transfer areas comprises an annular groove running around the circumferential surface of the coupling section. In this way it is ensured that the corresponding fluid transfer area is securely connected to the corresponding bore in the hydraulic block, regardless of whether the coupling section of the pressure intensifier has been pushed slightly more or slightly less deeply into the hydraulic block, or which twisting position the coupling section is in takes there.

The coupling section has an external thread for screwing the coupling section into the hydraulic block. In this way, the coupling section is mechanically securely anchored in the hydraulic block.

The plurality of fluid transfer areas are preferably arranged between the free end of the coupling section that is to be inserted into the hydraulic block and the external thread of the coupling section. The outer diameter of the coupling section usually tapers at the transition between the external thread and the rest of the coupling section. Typically, the cylinder block of the pressure booster has a molded hexagon for attaching a screwing tool.

Preferably, the coupling section is traversed by at least two bores running parallel to the longitudinal axis of the pressure booster, which extend from the free end face of the coupling section into the area of the cylinder block of the pressure booster, which is always positioned outside the hydraulic block receiving the coupling section.

With such bores in the coupling section running parallel to the longitudinal axis of the pressure amplifier, the required fluidic connection can be easily established between the corresponding channels inside the cylinder block of the pressure amplifier and the fluid transfer areas. The holes can be made in one operation from the front side of the coupling section until they intersect with the channels to be connected through them inside the pressure amplifier. In particular, such bores make it very easy to form one of the fluid transfer areas on the free end face of the coupling section and the other of the fluid transfer areas in the area of the peripheral surface of the coupling section.

Independent protection is claimed for a hydraulic unit with a hydraulic block, in which several bores through which hydraulic fluid flows are formed for connecting different hydraulic active elements (controllable or non-controllable valves and / or pumps and / or pressure compensation tank and / or several pressure amplifiers), and at least one Pressure amplifier of the type according to the invention, wherein the pressure amplifier has a coupling section which is inserted into a bore in the hydraulic block and fixed there.

It is particularly advantageous if at least two, preferably three, pressure amplifiers are connected in series on the hydraulic unit, so that the high pressure supplied by a pressure amplifier preceding in the (high-pressure) flow direction represents the pressure with which a pressure amplifier following the flow direction is fed on the input side. In this way, particularly high pressures can be generated in a cascading manner. The hydraulic unit can be designed to be particularly compact because the pressure boosters do not require any piping or hydraulic hoses to connect to the hydraulic block and can therefore be installed very close together on the hydraulic block.

Further advantages, modes of operation and design options of the invention result from the following description of the exemplary embodiments based on the figures.

Figure list

• The Figure 1 shows the hydraulic circuit diagram developed into a single level and the conditions during a work cycle of the pressure booster piston.
• The Figure 2 shows the same hydraulic circuit diagram developed into a single level and the conditions at a point in time when the pressure booster piston has reached its top dead center after a work cycle.
• The Figure 3 shows the same hydraulic circuit diagram developed into a single level and the conditions during a charging cycle of the pressure booster piston.
• The Figure 4 shows building on the Figure 1 the conditions in normal operation, in which fluid is generated using an appropriately connected external switching valve and is dispensed under high pressure.
• The Figure 5 shows building on the Figure 1 the conditions in switching mode, in which the high-pressure consumer is depressurized or even emptied using an appropriately connected, external switching valve back via the pressure amplifier.
• The Figure 6 shows a first, physically concrete embodiment of the pressure amplifier according to the invention.
• The Figure 7 shows - as an excerpt from the Figure 6 - the coupling section of the pressure booster.
• The Figure 8 shows a second, physically concrete embodiment of the pressure amplifier according to the invention.
• The Figure 9 shows the pressure amplifier according to Figure 8 in an enlarged half section.
• The Fig. 10 shows the exemplary embodiment according to. Fig. 6 and 7 shown in perspective when removed from the hydraulic block.
• The Fig. 11 shows the exemplary embodiment according to. Fig. 6 and 7 when removed from the hydraulic block, in side view.
• The Fig. 12 shows the exemplary embodiment according to. Fig. 8 and 9 shown in perspective when removed from the hydraulic block.
• The Fig. 13 shows the exemplary embodiment according to. Fig. 8 and 9 when removed from the hydraulic block, in side view.

Examples of embodiments Basic working principle of the pressure amplifier described as an exemplary embodiment

First of all, the basic principle of the pressure amplifier according to the invention must be explained, which is characterized by its particularly simple structure and is therefore predestined to create a particularly compact pressure amplifier, so that the pressure amplifiers that work according to this principle are predestined to be equipped with the connection which forms the core of the invention.

For this purpose, refer to the Fig. 1 referred.

The Fig. 1 shows the pressure amplifier 1, which is completely formed in a metal, preferably steel, cylinder block 13, which is cut here and is therefore initially only shown schematically as a box-like outline by four solid lines forming a rectangle. The cylinder block preferably has the outer contour of a cylinder which is rotationally symmetrical about the longitudinal axis L. The cylinder block 13 consists of at least two and ideally three separate, ie separable, cylinder block elements that are not connected to one another in terms of material. In the specific case of Fig. 1 In the preferred embodiment shown, the cylinder block 13 consists of the three cylinder block elements 13.1, 13.2 and 13.3, as indicated by the dashed dividing lines. The several cylinder block elements are fixed to one another in a defined position relative to one another in a form-fitting manner, for example using dowel pins not shown here.

A pressure booster piston 2 works in this cylinder block. This pressure booster piston 2 is typically designed as a differential piston with two differently sized hydraulic active surfaces that act in opposite directions and then consists of a low-pressure piston N with a large diameter and a high-pressure piston H with a small diameter, which are fixed to each other are connected by a piston skirt S. The low-pressure piston N forms a low-pressure working space 10 in the cylinder block, while the high-pressure piston H forms a high-pressure working space 11 in the cylinder block. A gap 12 is formed between the two pistons in the area of their connection by the piston skirt S, the function of which will be explained later. The pressure booster piston preferably has a longitudinal axis which is parallel to the longitudinal axis L of the cylinder block 13.

It is easy to understand that the gear ratio, i.e. H. the factor by which the fed-in low pressure can be increased depends on the diameter ratio DN/DH of the low-pressure piston N and the high-pressure piston H.

In addition, a control piston 3 works in the cylinder block 13. Preferably, its longitudinal axis is also parallel to the longitudinal axis L of the cylinder block 13. Ideally, the control piston and the differential piston are arranged completely or at least predominantly next to one another, seen perpendicular to the longitudinal axis.

As you can also see, all the connecting lines that are needed to make the pressure booster functional are in the cylinder block 13. It should be noted that the Fig. 1 shows the pressure booster piston 2, the control piston 3 and all the connecting lines required for operation projected into one plane for better clarity. Preferably, ie in reality, the components mentioned do not all lie in one plane, because such an arrangement would make extremely poor use of the cross section of the cylinder block: In the of Fig. 1 In the plane shown in the drawing, the pistons and the connecting lines would crowd each other, while in a cutting plane perpendicular to the longitudinal axis, no piston and almost no connecting lines would be found.

The pressure amplifier communicates to the outside via its external low-pressure connection 5 with an external low-pressure source. From this, the pressure booster draws hydraulic fluid under lower pressure, which drives it. Preferably, part of this hydraulic fluid fed into the pressure booster at lower pressure is put under higher pressure in the pressure booster and output from the pressure booster to an external consumer as hydraulic fluid under higher pressure. In addition, the pressure booster has an external tank connection 6, via which it releases at least part of the hydraulic fluid drawn at lower pressure to the outside when this hydraulic fluid has completed its work within the pressure booster. Delivery is preferably made to an external tank or an external hydraulic fluid reservoir, but this is not mandatory. In addition, the pressure intensifier has another connection, the so-called external high-pressure connection 7. Via its high-pressure connection, the pressure intensifier releases hydraulic fluid that has been placed under higher pressure (compared to the lower pressure in the supply) to a hydraulic machine, such as a rescue scissor, a clamping device or a hydraulic collet chuck. As far as the term “external connection” is used here, it means that a connection is external because the pressure amplifier can be directly connected to the environment via this connection. In contrast to this, there are internal connections, such as connecting channels, through which the hydraulic functional components inside the pressure amplifier are connected to one another are connected.

How to do relatively well based on the Fig. 1 sees, a low-pressure line 8 connects to the external connection 5 to the low-pressure source within the cylinder block 13. The low pressure line 8 soon branches off. It branches into a low-pressure line section 8.1, which primarily serves to supply the high-pressure working space with fresh low-pressure fluid, and also serves to supply the control piston 3 with low pressure via the low-pressure line section 8.4. The preferred low-pressure line section 8.2 leads past the high-pressure working space directly into the line that leads to the high-pressure consumer. The low-pressure line section 8.2, if present, serves to initially fill a newly connected, still empty high-pressure consumer with low-pressure fluid and to displace the air from the possibly initially empty lines of the high-pressure consumer, so that high-pressure generation can then begin .

A tank or return flow line 9 is connected to the connection 6 to the external tank. The tank or return flow line 9 soon branches off within the cylinder block 13 into a return flow line section 9.1, which comes from the control piston, and a line section 9.2, which, as will be discussed later, at a given time and with the appropriate, i. d. R. externally implemented hydraulic circuit of the pressure amplifier serves as a control line for the controllable check valve 4.3.

In addition, a connecting line 14 from the control piston to the pressure booster piston is provided, the function of which will be explained in more detail later.

Regarding the control piston 3, it should be said that this control piston 3 is also designed as a differential piston.

Based on Fig. 1 The basic functionality of the pressure intensifier can be explained quite clearly:
In the phase that the Fig. 1 shows, a work cycle is currently taking place, ie the pressure booster piston 2 moves in the direction of the black arrow into the high-pressure working space 11. At the beginning of the work cycle, the high-pressure working space 11 is initially filled with low-pressure fluid, ie preferably with fluid that is under the low pressure of the feed pump. By moving the pressure booster piston into the high-pressure working space 11, the fluid located there is put under increased pressure and delivered to the high-pressure consumer via the check valve 4.2 and the external high-pressure connection 7.

The low-pressure working space 10, which continuously enlarges over the course of the work cycle, is constantly supplied with low-pressure fluid, i.e. H. refilled with fluid obtained under the low pressure via the external low-pressure connection 5. This refilling takes place via the connecting line 14. This is connected to the low-pressure line section 8.4, which carries fluid under low pressure, using the control piston 3 - namely via its slimmed area V1, which is between the connections C and P.

The control piston 3 remains in the position of Fig. 1 position shown. It is indeed constantly subjected to low pressure on one (here the lower) end face via the low-pressure line section 8.3. At the same time, however, it has also been subjected to low pressure on its opposite (here the upper) end face via the control line 8.5 since the start of the work cycle. The reason for this is that the high-pressure working space was filled with low-pressure fluid at the beginning of the work cycle using the low-pressure line section 8.1. The low pressure in the control line 8.5 is maintained even when the high-pressure piston has passed over the mouth of the control line 8.5 in the high-pressure working space and thereby sealed it. Due to the fact that the low pressure on the upper end face of the control piston 3 acts on a larger area than on the lower end face of the control piston 3, a resulting downward force permanently acts on the control piston.

It is also important to mention that the intermediate space 12 is also connected to the external tank connection 6, i.e. it is kept depressurized. This is necessary in order to be able to drain away any leakage that may possibly flow from the high-pressure working space and/or from the low-pressure working space into the intermediate space 12, so that no disruptive back pressure can build up in this intermediate space because hydraulic fluid may be trapped.

The work cycle continues until the pressure booster piston 2 reaches the of Fig. 2 position shown, ie it has reached its top dead center. How to use the Fig. 2 As you can see, the high-pressure piston of the pressure booster piston has now penetrated so deeply into the high-pressure working space 11 that its edge facing the intermediate space 12 has now released the mouth of the control line 8.5 again, i.e. it no longer runs over it and thereby seals it. As a result, the mouth of the control line 8.5 is connected to the unpressurized space 12, ie the pressure that previously existed in the control line 8.5 during the work cycle collapses. Because of this, only one end face of the control piston is now subjected to low pressure, namely the lower end face of the control piston 3 in the picture. Therefore, the control piston 3 is pushed into its other position, ie from that of Fig. 1 position shown in that of Fig. 2 shown position promoted.

As a result of the said displacement of the control piston 3 into its second position, its slimmed area V1 is no longer hydraulically connected to the connecting line 14. Instead, the connecting line 14 is slimmed down via the second one Area V2 of the control piston 3 is hydraulically connected to the return flow line section 9.1. This leads to the low pressure in the low-pressure working space 10 collapsing because the low-pressure working space 10 is now depressurized. As a result, the forces that act on the upper end face of the high-pressure piston now predominate, which is why the pressure booster piston 2 now begins to move downward and to displace the hydraulic fluid still in the low-pressure working space 10 via the connecting line 14 and the return flow line section 9.1, so that it over the external tank connection 6 is delivered.

While the Fig. 2 shows the top dead center, i.e. the moment at which the pressure booster piston 2 stopped in its movement and the direction of movement changes Fig. 3 the charging cycle, during which the pressure booster piston 2 penetrates deeper into the low-pressure working space. The snapshot that the Fig. 3 shows the pressure booster piston just before its bottom dead center, but at the moment it is still moving downwards.

Based on Fig. 3 You can already guess what will happen shortly: You can see that the edge of the high-pressure piston facing the high-pressure work space 11 is about to connect the mouth of the currently unpressurized control line 8.5 with the high-pressure work space 11, which is currently under low pressure. As soon as this has happened, the low pressure currently prevailing in the high-pressure working space 11 spreads over the control line 8.5 and reaches the previously unpressurized (upper) end face of the control piston 3. As soon as pressure is present here, the control piston 3 is driven downwards, since the previously unpressurized Front side has a larger area than the other, smaller end face of the pressure booster piston, which is permanently under low pressure.

As soon as the control piston 3 has been driven back into its other position, its slimmed area V1 will again connect the connecting line 14 with the low-pressure line section 8.4 carrying low pressure, so that the pressure in the low-pressure working space 10 changes again. The low-pressure work space 10, which is currently not under external pressure, is then subjected to the low pressure of the low-pressure source again. At this moment the pressure booster piston 2 reaches its bottom dead center and pauses briefly. The charging cycle comes to an end and a new working cycle begins, as described by Fig. 1 shown begins.

It should also be noted that a significant advantage for today's invention is that the control piston works without a spring. The otherwise necessary application of the closing force of a spring is replaced by the constant application of low pressure to one end face. This contributes to the achievement of the goal of making the pressure amplifier smaller, since the installation space required to accommodate a spring that can be installed in a replaceable manner at a later date is eliminated.

Based on Fig. 4 It is easy to see what the purpose of the return line section 9.2 is, which leads from the tank or return line 9 to the controllable check valve 4.3.

This line serves to relax the high-pressure consumer at the appropriate time.

In order to do this, the polarity is reversed, so to speak, using a preferably externally arranged switching valve. H. The connection 5, which was previously connected to the external low pressure, is now depressurized or connected to the tank via a valve that is preferably external, outside the cylinder block 13, and the connection 6, which was previously connected to the external tank, is now connected to the low-pressure source. Due to this, low pressure can be brought to the control piston via the return flow line section 9.2 to the control piston, which opens the controllable check valve 4.3, so that the line to the high-pressure consumer, which was previously closed off from the environment by the check valves 4.1 and 4.2, via the now unpressurized low-pressure line section 8.2 hydraulic fluid over the previous one Low-pressure line 8 and the now unpressurized, previous low-pressure connection 5 can be discharged.

Now it needs to be explained in more detail how the controllable check valve 4.3 works.

The pressure amplifier according to the invention is operated with a switching valve 25, which is preferably mounted externally. In normal operation, the changeover valve 25 is switched so that it is already based on the Figures 1 to 3 The operation discussed takes place in which high-pressure fluid is generated, cf. Fig. 4 .

In order to relax the high-pressure consumer, which is regularly necessary, for example, if it is a clamping device that is supposed to release the workpiece clamped by it again at the end of processing, the switching valve 25 is switched to the position as shown Figure 5 shows. Basically nothing else happens other than the external connections 5 and 6 are “reversed”. Port 5, through which the externally generated low pressure was previously fed in, is now depressurized and thus corresponds to the tank or Return connection. The external connection 6, which was previously operated as a tank or return connection, is now, for. B. via the external low-pressure feed pump 26, with low pressure and thus itself to the low-pressure connection. The result of this is that line section 9.2 is no longer depressurized, but now carries low pressure. This low pressure lifts the valve body of the controllable check valve 4.3 from its seat, thus unlocking the check valve 4.3. The hydraulic fluid previously stored in the high-pressure consumer then flows out into the tank via the check valve 4.3 and the line 8.2. Of course, this means that the pressure in the high-pressure consumer immediately collapses and then The hydraulic system of the high-pressure consumer is emptied into the tank, whereupon the high-pressure consumer can be disconnected, which is very practical, for example, when it involves rescue scissors and the operation is finished.

The one in the is also noteworthy Fig. 1 to 4 Pilot hole that can be recognized and forms a throttle. While the pilot control bore is symbolized schematically as a bypass throttle 24* in the figures, in reality it is preferred that the pilot bore penetrates the upper part of the control piston 3 which is hatched to the right and can be seen in the figures. It connects the area of the upper free end face of the control piston 3 with the slimming V1. In this way, the control line 8.5 is permanently connected to the slimming V1. The purpose of this pilot control hole is to ensure a defined position of the pressure booster piston 2 even if the pressure booster has stood still for a long time. As long as the pilot control hole is missing, it can happen that after the pressure booster piston has been stationary for a long time, the control line 8.5 has lost the pressure initially contained in it due to microleakage and the control piston 3 then assumes an undefined position, which makes it difficult to start up again. The purpose of the pilot control hole is to always ensure that the control line 8.5 is still correctly pressurized even after a long time and therefore forces the control piston 3 into a defined position, which enables the pressure intensifier to start up again without any problems. The flow flowing through the pilot bore is chosen so that it is so low that it plays no role during ongoing operation. Only during longer downtimes does the flow through the pilot bore add up and thus produce the desired effect, as described above.

The coupling section essential to the invention

The Fig. 6 and 7 show a concrete, physical embodiment of a pressure amplifier according to the invention.

The Figure 7 shows the coupling section of the pressure amplifier according to. Fig. 6 in an enlarged view.

The Fig. 6 shows the pressure amplifier 1 according to the invention in its mounted position on an external hydraulic block 100. The hydraulic block is not part of the pressure amplifier, but represents, for example, the hydraulic control block of a clamping device. The hydraulic control block is actually a solid metal control block (no pipe sleeve or similar) in which a large number of hydraulic channels are formed and which, for example. B. also includes the actuator through which the user controls the system hydraulically.

As can be seen, the cylinder block 13 or its cylinder block element 13.1 merges integrally into a coupling section 101, i.e. H. Part of the peripheral surface of the cylinder block of the pressure booster forms the coupling section 101.

The coupling section 101 has a circular cylindrical shape. It preferably has a diameter that is reduced compared to the rest of the cylinder block 13, which is also usually circular cylindrical, ideally by at least 30%.

The diameter of the coupling section 101 preferably corresponds to the core diameter of a metric thread and is reduced compared to this by a tolerance amount which allows the part of the coupling section 101 that does not have an external thread to be pushed through the section of the hydraulic block 100 that has an internal thread.

The length of the coupling section 101 in the direction of the longitudinal axis L of the pressure booster 1 is preferably at least 25%, better at least 30%, of the total length of the cylinder block 13 of the pressure booster 1. This ensures that the coupling section 101 can penetrate deep enough into the hydraulic block 100 an area that lies in the solid material of the hydraulic block, below the mostly flat surface of the hydraulic block 100 surrounding the bore for inserting the coupling section 101.

As a rule, the coupling section 101, when installed in the hydraulic block 100, is surrounded on its circumference by solid material of the hydraulic block (possibly traversed by local channels), which, viewed in the radial direction, has a thickness of at least around is larger by a factor of 1.5 than the largest radius of the circular cylindrical cylinder block 13. This means that the fluid transfer can take place where the hydraulic block 100 has a high strength or rigidity. In this context, it should be borne in mind that the "low pressure" or lower pressure feeding the pressure amplifier does not necessarily have to be a low pressure in absolute terms. Because where a very large pressure difference has to be overcome, the pressure amplifiers according to the invention can be used in cascade, i.e. H. a subsequent pressure amplifier is then fed by the high pressure of the previous pressure amplifier.

The coupling section 101 not only ensures a fluid connection between the pressure booster 1 and the hydraulic block 100, which the pressure booster supplies. Rather, it also holds the pressure amplifier 1 mechanically in its installed position by predominantly or completely absorbing the weight and all forces occurring during operation as a result of the mass of the pressure amplifier 1 and passing it on to the hydraulic block 100, e.g. B. the acceleration forces that occur on the pressure booster when the hydraulic block rotates or moves.

The coupling section 101 is designed so that it has been inserted into a hole in the hydraulic block 100 that receives it and has been fixed there. For this purpose, the coupling section 101 is provided with an external thread 102, which is screwed into a corresponding mating thread of the hole in the hydraulic block 100 that accommodates the coupling section 101.

As can be seen, the coupling section 101 is designed in such a way that the receiving bore of the hydraulic block 100 can completely enclose it on its circumference and on its free end.

How best to use the Fig. 7 As can be seen, two fluid transfer areas 104 and 105 are formed on the coupling section 101. They lie one behind the other when viewed in the direction of the longitudinal axis L of the pressure amplifier and, when viewed in the screwing-in direction of the coupling section, they may lie in front of the area of the coupling section provided with an external thread 102.

The first fluid transfer region 104 is preferably formed on the peripheral surface of the coupling section 101. The second fluid transfer area can either also be formed on the peripheral surface of the coupling section 101 or preferably on its free end face.

The pressure amplifier communicates directly to the outside with the hydraulic block 100 via these fluid transfer areas 104, 105 (and only via these). These two fluid transfer areas are hydraulically separated from one another by a seal 106. The seal is preferably designed as a seal inserted with or without a support ring in a circumferential ring groove on the coupling section. In addition - preferably in the same way - a further seal 107 is provided, which seals the fluid transfer area 104 located closer to the outside from the outside.

The coupling section 101 preferably has two bores 108 and 109, which usually run parallel to the longitudinal axis L. These extend from the free end of the coupling section 101 through the coupling section into the area of the cylinder block 13 (or 13.1), which is also connected to the hydraulic block mounted pressure amplifier lies outside the hydraulic block 100.

One hole 108 goes into that of the Fig. 1 to 5 shown low pressure line 8 above. This bore preferably opens into the free end of the coupling section and provides the external low-pressure connection 5 (cf. Fig. 1 ) of the pressure intensifier.

This is located in the fluid transfer area 105, via which the pressure amplifier can be connected to the low-pressure feed line, which here opens into the bottom of the bore of the hydraulic block 100, which receives the coupling section 101. The fluid transfer area 105 is designed in such a way that a fluid-conducting connection can be established between the pressure booster and the hydraulic block via it, regardless of the absolute screw-in depth or the angle of rotation that the coupling section has covered when screwed into the hydraulic block.

The other hole 109 goes into that of the Fig. 1 to 5 tank or return line 9 shown above. It is closed by a plug 110 where it actually opens into the free end of the coupling section 101. It is intersected with a transverse bore 111, which opens into an annular groove 112. The annular groove 112 is located in said further fluid transfer area 105. This represents the external tank connection 6.

As a result of its equipment with the annular groove 112, the fluid transfer area 104 is also designed in such a way that a fluid-conducting connection between the pressure amplifier and the hydraulic block is established via it, regardless of the absolute screw-in depth or the angle of rotation that the coupling section 101 has covered when screwed into the hydraulic block 100 can be produced.

It should also be noted that the fluid transfer area 105 can alternatively be designed accordingly, like the fluid transfer area 104, i.e. can lie on the peripheral surface of the coupling section. However, such a design is not preferred.

It is particularly expedient to provide the section of the cylinder block 13 lying outside the hydraulic block 100 with a coupling section for a screwing tool, preferably in the form of an external hexagon - which is not shown in the drawing in this exemplary embodiment.

In this exemplary embodiment, the external high-pressure connection 7 is preferably located on the side of the pressure amplifier 1 facing away from the coupling section 101. Here, a fluid-conducting connection to the high-pressure consumer takes place in a conventional manner.

The Figures 8 and 9 show a second concrete embodiment of the pressure amplifier according to the invention. The previous statements for the first exemplary embodiment also apply here, unless otherwise described below.

Here the clutch section is formed by the majority of the peripheral surface of the cylinder block 13. The cylinder block 13 of the pressure booster 1 is preferably designed so that it can be inserted into a bore of the hydraulic block 100 over at least ½, better 2/3 of the length that the cylinder block 13 has in the direction of its longitudinal axis L. In this specific case, the cylinder block is designed such that the first and second cylinder block elements 13.1 and 13.2 can be completely inserted into the hydraulic block 100. The highly loaded area of the pressure booster, in which the differential piston moves back and forth, is now completely in the hydraulic block, which therefore has a stiffness-increasing supporting effect. As you can see, the coupling section 101 is also designed here so that the receiving bore of the hydraulic block 100 completely encloses it on its circumference and on its free end can.

Here too, the diameter of the coupling section preferably corresponds to the core diameter of a metric thread and is reduced compared to this by a tolerance amount that allows the part of the coupling section that does not have an external thread to be pushed through the section of the hydraulic block that has an internal thread.

In this exemplary embodiment, three fluid transfer areas 104, 105 and 113 are formed on the coupling section 101. They lie one behind the other when viewed in the direction of the longitudinal axis L of the pressure amplifier and, when viewed in the screwing-in direction of the coupling section, they may lie in front of the area of the coupling section provided with an external thread.

The pressure amplifier 1 communicates directly to the outside via these fluid transfer areas 104, 105 and 113 (and only via these). H. with the hydraulic block. An additional hose or pipe connection for connecting to the high-pressure consumer is not provided here; the high-pressure consumer is fed by the pressure amplifier 1 via the hydraulic block 100.

The first fluid transfer area 104 is delimited on both sides by seals 114, which are preferably cord seals inserted with or without a support ring in a circumferential ring groove on the coupling section 101.

The in Fig. 8 Easily recognizable low-pressure line section 8 opens into a transverse bore, which on its other side opens into the outer surface of the cylinder block or (where present) of the second cylinder block element 13.2, within the first fluid transfer area 104. This forms the external low-pressure connection 5. For reasons of strength, the cylinder block 13 preferably does not have an annular groove in this area, but is smooth and therefore unweakened. The corresponding annular groove is here instead preferably mounted in the hydraulic block 100.

In the Fig. 8 The "tank line" shown is preferably extended through a bore running within the cylinder block 13 into the area of the front shoulder 116 of the coupling section 101, where it opens into the second fluid transfer area 105. This represents the external tank connection 6. The second fluid transfer area is preferably limited in the direction of the outside of the hydraulic block by a further seal 118 and is therefore kept small, the seal preferably also lying in a circumferential annular groove of the coupling section and can correspond to the seals 114, 115.

The front shoulder 116 is formed in that the coupling section tapers here.

The tapered cylinder extension 117 of the coupling section 101 is designed so that it can be inserted into a second, tapered part of the receiving hole, which is designed here as a stepped hole in the hydraulic block 100. The tapered cylindrical extension 117 has at least one, preferably two, circumferential annular grooves into which one or two seals 119 are inserted - usually with support rings. These one or two seals seal the third fluid transfer area 113 from the second fluid transfer area 105. The third fluid transfer area is therefore formed at the free end of the coupling section 101. The high-pressure line opens into the free end, so that the external high-pressure connection 7 is formed here.

The said tapering of the cylindrical extension 117 takes place taking into account the high pressure there. This preferably makes it necessary to keep the lengths to be sealed small and also to keep the areas exposed to the high pressure effect and thus the forces that arise there small.

Independent protection is also claimed for a pressure amplifier cascade consisting of a hydraulic block 100 and several pressure amplifiers 1 connected hydraulically in series, characterized in that the pressure amplifiers 1 attached next to one another on the hydraulic block 100 are those according to one of the preceding claims.

Reference symbol list

1

Pressure booster

2

Pressure booster piston

3

control piston

3.1

Control sleeve of the control piston

3.2

Damping piston

4.1

check valve

4.2

check valve

4.3

controllable check valve

5

External low pressure connection (low pressure connection)

6

External tank connection (tank connection)

7

Connection of external high-pressure consumers (high-pressure connection)

8th

Low pressure line

8.1

Low-pressure line section to the high-pressure work area

8.2

Low pressure line section to the high pressure consumer

8.3

Low-pressure line section for permanent preloading of the control piston

8.4

Low-pressure line section to enable the control piston to forward low-pressure working fluid

8.5

Control line

9

Tank or return line

9.1

Return line section to the high pressure consumer

9.2

Return flow line section to the control piston

10

Low pressure workspace

11

High pressure workspace

12

space

13

Cylinder block

13.1

first cylinder block element

13.2

second cylinder block element

13.3

third cylinder block element

14

Connecting line from the control piston to the pressure booster piston

15 to 24

not awarded

24*

Bypass throttle

25

changeover valve

26

external low pressure feed pump

27

up to 99 not awarded

100

Hydraulic block

101

Coupling section

102

Coupling section thread

103

Coupling section thread

104

first fluid transfer area

105

second fluid transfer area

106

poetry

107

poetry

108

drilling

109

drilling

110

Plug

111

Cross hole

112

Ring groove

113

third fluid transfer area

114

poetry

115

poetry

116

forehead heel

117

Cylindrical process

118

further seal

119

further seal

L

Longitudinal axis of the pressure booster or its cylinder block

H

High pressure piston

N

Low pressure piston

S

Piston skirt

DH

Diameter of high pressure piston

DN

Diameter of low pressure piston

V1

first slimmed down area of the control piston

V2

second slimmed area of the control piston

DW

Wall thickness of the adapter sleeve in the radial direction

D

clear inner diameter of the adapter sleeve

Claims (12)

1. A pressure intensifier (1) for fluids, in particular for liquids, comprising a cylinder block (13) in which a pressure intensifier piston (2) and a control piston (3) move cyclically, wherein the pressure intensifier piston (2) forms a high-pressure working chamber (11) and a low-pressure working chamber (10) in the cylinder block (13) and the cylinder block (13) has a low-pressure connection (5) for feeding in low-pressure fluid from outside, a high-pressure connection (7) for discharging higher-pressure working fluid towards the outside and a connection for discharging fluid whose working capacity in the pressure intensifier (1) is exhausted, wherein the cylinder block (13) has a coupling portion (101) rigidly connected with it, which can be inserted into a receiving bore of a hydraulic block (100) and fixed there, so that the receiving bore encloses the coupling portion (101), wherein the coupling portion (101) has at least two fluid transfer regions (104, 105, 113) fluidically separated by a seal, for exchanging fluid between the pressure intensifier (1) and the hydraulic block (100) into which it is inserted, characterized in that the coupling portion (101) has a thread (102) for screwing the coupling portion (101) into a hydraulic block (100).
2. The pressure intensifier (1) according to claim 1, characterized in that (coming from inside the cylinder block (13)), a channel, via which the pressure intensifier (1) discharges fluid in operation whose working capacity is exhausted, leads into a fluid transfer region (104, 105, 113), and that a further channel, via which low-pressure fluid is fed into the pressure intensifier (1), leads into another fluid transfer region (104, 105, 113).
3. The pressure intensifier (1) according to claim 1 or 2, characterized in that the coupling portion (101) has a third fluid transfer region (113) for transferring the higher-pressure working fluid to the hydraulic block (100).
4. The pressure intensifier (1) according to any one of the preceding claims, characterized in that at least one of the fluid transfer regions (104, 105, 113) comprises a peripheral annular groove (112).
5. The pressure intensifier (1) according to any one of the preceding claims, characterized in that at least one channel leads into the end face (entire end or end surface of an annular shoulder) of the coupling portion (101), ideally the channel via which the higher-pressure working fluid is discharged by the pressure intensifier (1).
6. The pressure intensifier (1) according to any one of the preceding claims, characterized in that the fluid transfer regions (104, 105, 113) are disposed between the free end of the coupling portion (101) to be inserted into the hydraulic block (100) and the thread (102) of the coupling portion (101).
7. The pressure intensifier (1) according to any one of the preceding claims, characterized in that the cylinder block (13) of the pressure intensifier (1) has a molded-on hexagon.
8. The pressure intensifier (1) according to any one of the preceding claims, characterized in that at least two bores (108, 109) extending parallel to the longitudinal axis (L) of the pressure intensifier (1) run through coupling portion (101), which extend from the free end face of the coupling portion (101) into the area of the cylinder block (13), which is always positioned outside the hydraulic block (100) accommodating the coupling portion (101).
9. The pressure intensifier (1) according to claim 8, characterized in that the end leading into the free end face of the coupling portion (101) is sealed by a plug (110) at at least one of the bores (108, 109), and that this bore (108, 109) intersects a cross bore (111) that leads into a fluid transfer region (104).
10. A hydraulic unit comprising a hydraulic block (100) in which several bores, through which hydraulic fluid flows, for connecting different hydraulic operative units are formed, and at least one pressure intensifier (1) according to any one of the preceding claims, characterized in that the pressure intensifier (1) has a coupling portion (101) inserted into a bore in the hydraulic block (100).
11. The hydraulic unit according to claim 10, characterized in that the hydraulic unit comprises several pressure intensifiers (1) according to any one of the claims 1 to 11, each of which has a coupling portion (101) inserted into a bore of the hydraulic block (100).
12. The hydraulic unit according to claim 11, characterized in that at least two, better at least three, pressure intensifiers (1) are connected in series one behind the other, so that the high pressure provided by a pressure intensifier (1) preceding in the flow direction constitutes the pressure with which a subsequent pressure intensifier (1) in the flow direction is supplied on the input side.

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