KR20140013976A - Device for throttling fluid flow and corresponding piston pump for delivering fluids - Google Patents

Abstract

The present invention relates to a throttling device (10) of fluid flow, which includes a spring member (12) forming a throttling point (14) having an open cross section capable of being determined in advance, together with a fluid channel (3.2), wherein the spring member (12) is formed as an open ring having two spring legs (12.1, 12.2), and elastically formed in at least one throttling point (14) region, so that the open cross section of the throttling point (14) is able to be variably set according to the pressure difference. The present invention relates to a piston pump including the throttling device. According to the present invention, an extension part is formed on the first spring leg (12.1) as a sealing strap (12.3), and the extension part covers at least one throttling point (14), and variably sets the open cross section of the throttling point (14) according to the pressure difference.

Description

Throttle device for fluid flow and piston pump for fluid delivery {DEVICE FOR THROTTLING FLUID FLOW AND CORRESPONDING PISTON PUMP FOR DELIVERING FLUIDS}

The invention relates to a throttle device for fluid flow according to the preamble of the independent claim 1. The present invention further relates to a fluid pump piston pump comprising such a throttle device.

Piston pumps for delivery of pressure media in hydraulic brake systems with ABS and / or anti-lock braking systems (ABS) are known in the prior art in various embodiments. For example, a vehicle brake system often uses a radial piston pump that includes a plurality of pump members for delivery of pressure medium, in which at least one piston can be reciprocated by an eccentric body. Typically, the so-called pump members consist of a piston, a piston operating face, often formed as a cylinder, an inlet and outlet valve and a sealing member. The valves are used for fluid control during pump movement of the piston. In this case, the inlet valve is used for not flowing back the fluid into the suction chamber during the compression step, and the discharge valve prevents the backflow of the fluid from the pressure side into the pump inner chamber. Typically the valves are formed as spring loaded ball valves, the discharge channel for the discharge valve is formed by a so-called discharge valve cover and a pump cylinder, and the discharge valve is received in the discharge valve cover.

The discharge valve cover known in the prior art is manufactured by cutting or deformation, and from an economic point of view many parts are provided with a deformation method. Discharge structures such as size and width are suitably formed because they affect the vibration behavior of the pump member and hence the noise behavior. This formation is usually a suitable tapering of the discharge channel, which tapering acts as a fixed throttle. By this throttle action, a hydraulic low pass filter is formed, which acts positively on the noise. The behavior of the dynamic viscosity of the brake fluid in the range of 0 ° C. to 120 ° C. can be seen to be almost constant, in which the optimum throttle action is defined. Due to the large fluctuations in the kinematic viscosity of the brake fluid over the required temperature range of -40 ° C to 120 ° C, the throttle loads the entire pump drive and the parts under compression of the pump element, especially at low temperatures. The narrowed cross section results in a much increased liquid friction at low temperatures, which leads to a significant excessive rise in the internal pressure of the pump and hence the load. In the prior art, fluid flow throttle devices are known which comprise a control member in the discharge channel which provides a constant pump internal pressure by widening the effective cross section of the discharge channel in the case of high viscosity fluids or large volume flows.

DE 10 2010 040 169 A1 discloses, for example, a fluid flow throttle device and a piston pump for fluid delivery comprising the throttle device. The disclosed fluid flow throttle device includes a base body, the base body including at least one throttle point having an open cross section that can be predetermined. In this case, the base body is elastically formed in the region of the at least one throttle point, so that the open cross section of the at least one throttle point can be set variably according to the pressure difference. The predetermined minimum open cross section of the throttle point with the shape determined by the two spring legs allows for an increase in the fluid flow through the outlet channel of the throttle point up to the limit pressure difference value determined by the spring behavior. If the pressure difference rises above the threshold pressure difference value, the two spring legs are stretched in a predetermined direction, thereby increasing the open cross section of the throttle point and the flow amount of the fluid and reducing the effective pressure difference. The base body of the throttle device is formed, for example, as an open ring with a round wire having two spring legs and one throttle point, which throttle point is formed between the end faces of the two spring legs.

An object of the present invention is to provide a throttle device in which the spring member of the throttle device has a dynamic behavior when the pressure difference rises.

The object is achieved by a throttle device of fluid flow having the features of independent claim 1, and a piston pump having the features of independent claim 6. The throttle device according to the invention and the piston pump according to the invention have the advantage that the spring member of the throttle device has a dynamic behavior upon rise in pressure difference. In other words, the open cross section of the throttle point is variably set according to the pressure difference.

The essence of the present invention is that by elastically forming the base body of the throttle device, the throttle device has a dynamic behavior when the pressure difference rises. The throttle device according to the invention is designed such that it can preferably be reconditioned or opened elastically in the event of a deviation such as a pressure transient rise or higher volume flow at low temperatures. Due to this, for example, an increased internal pressure in the piston pump can be prevented and thus damage to the part can be prevented. Thus, a cost optimized design of the part can be achieved at the same pressure level. During "normal operation" within the linear behavior of the fluid, the throttle point flows through. As the viscosity and hence flow resistance increase due to temperature fluctuations, the cross section of the throttle point becomes slightly elastic. By means of the discharge direction on one side of the throttle device, the closing body of the discharge valve of the piston pump may appear in a preferential position, which acts positively on the noise behavior of the piston pump.

The dynamic throttle device according to the present invention allows an almost constant pressure differential to be set in the throttle device by the widening of the discharge channel in the high viscosity state of the fluid by the elastic base body including the discharge channel at the throttle point. With the dynamic throttle device according to the invention, the load on the drive output and the individual components that transmit the forces, such as bearings, pistons, high pressure sealing rings, etc., are reduced. By the design of the base body and the throttle point, the throttle behavior can be adapted to the function. Accordingly, embodiments of the present throttle device allow for qualitative improvement of the fluid system in which the throttle device is inserted. Another advantage is that clogging of the throttle point can be preferably prevented by the dynamic behavior of the throttle device. This can be used to reduce costs in suitable designs in future configurations. The throttle device according to the invention can be used not only with the piston pump but also for other assemblies of the fluid system.

Embodiments of the present invention provide a fluid flow throttle device having a spring member that forms a throttle point with an open cross section that can be predetermined with the fluid channel. In this case, the spring member is formed as an open ring with two spring legs and is elastically formed in the region of at least one throttle point, so that the open cross section of the throttle point can be set variably according to the pressure difference. According to the present invention, the first spring leg is provided with an extension embodied as a sealing strap, the extension covering at least one throttle point and variably setting the open cross section of the throttle point according to the pressure difference.

A piston pump according to the invention for delivering fluid comprises a piston, a pump cylinder, and a pressure chamber disposed between the inlet and outlet valves, which are closed by a cover and behind the outlet valve in terms of fluid flow. A throttle device according to the invention is arranged. The piston pump according to the invention can be used, for example, for the delivery of pressure medium in a vehicle brake system.

By means of the measures and improvements set forth in the dependent claims, a preferred improvement of the fluid flow throttle device set forth in the independent claim 1 and the piston pump for fluid delivery set forth in the independent claim 6 is possible.

It is particularly preferred that the extension, embodied as a sealing strap, be formed shorter than the fluid channel, so that the minimum open cross section of the fluid channel at the throttle point is fixedly given in advance. That is, the throttle point has a discharge channel with a predetermined minimum open cross section without being loaded. Additionally or alternatively, the maximum cross section of the discharge channel at the throttle point under load can be limited, for example by a stopper. The minimum open cross section of the at least one throttle point may preferably be optimized for volume flow, in particular in the predetermined temperature range of 0 ° C to 120 ° C. Due to temperature fluctuations, the viscosity of the fluid at the throttle point and hence the flow resistance changes. Thereby, the throttle point is further enlarged, so that the free cross section of the throttle point is enlarged or a new free cross section is set by the elastic behavior. Because of this, the pressure difference at the throttle point preferably does not rise, especially at low temperatures and does not damage other parts of the fluid system.

In a preferred embodiment of the device according to the invention, the spring members can be implemented staggered in the axial direction by a predetermined height. By the axially staggered embodiment, the spring member can be assembled to be prestressed in the axial direction by the pump cylinder and the cover. Because of this, the sealing strap can be supported on the floor and the spring member can be mounted without noise or "no rattling", since it is always fixedly seated.

In another preferred embodiment of the device according to the invention, the base body of the spring member is formed, for example, from round wires and / or flat wires and / or as a stamping part, which enables economic production of the throttle device.

In a preferred embodiment of the piston pump according to the invention, the base body of the spring member can be inserted into the receiving chamber, which is limited by the first side of the pump cylinder and the second side in the cover. The receiving chamber is substantially circular in shape and passes into the fluid channel. The formation of the accommodating chamber preferably allows for simple mounting of the throttle device.

In another preferred embodiment of the piston pump according to the invention, the receiving chamber comprises a support. The base body of the spring member may be inserted into the receiving chamber such that the sealing strap disposed on the first spring leg contacts the wall of the fluid channel and the spring end of the second spring leg contacts the support. For this reason, the torsional mounting of a spring member becomes possible preferably.

In another preferred embodiment of the piston pump according to the invention, the diameter of the base body of the spring member is realized larger than the diameter of the receiving chamber, whereby the spring member is inserted into the receiving chamber by prestress. In this case, the spring member preferably has a large strength. As an alternative, the diameter of the base body of the spring member is embodied smaller than the diameter of the receiving chamber so that the spring member can be inserted into the receiving chamber with radial play. In this case, the spring member preferably has a small spring stiffness.

Embodiments of the present invention are shown in the drawings and described in detail below. Parts or members having the same or similar function in the drawings are denoted by the same reference numerals.

According to the present invention, a throttle device is provided in which the spring member of the throttle device has a dynamic behavior when the pressure difference rises.

1 is a cross sectional perspective view of the rear region of a fluid delivery piston pump with an embodiment of a fluid flow throttle device according to the present invention;
2 is a bottom perspective view of the cover of the piston pump shown in FIG. 1, in which an embodiment of a fluid flow throttle device according to the invention is inserted;
3 and 4 are perspective views of an embodiment of a fluid flow throttle device according to the present invention.

As shown in FIGS. 1 and 2, the fluid delivery piston pump 1 according to the invention comprises a piston, a piston cylinder 5 and a cover 3 which are not shown. A pressure chamber 5.2 is disposed inside the pump cylinder 5 between the inlet valve and the discharge valve 20, which is not shown, and the pressure chamber is sealed by a cover 3, and within the cover, a discharge valve ( 20) is arranged. The cover 3 is fitted in the rear part embodied as a ledge 5.1 of the pump cylinder 5, thereby providing at least one fluid channel 3. 2 and at least one between the cover 3 and the ledge 5. 1. A discharge opening 3.4 is formed. The piston pump 1 according to the invention shown can for example be arranged in an unshown receiving hole of a pump housing or fluid block. Transversely extending pressure medium channels may be passed into the receiving hole, through which the fluid is guided through an unshown fluid filter into the inlet opening of the piston pump 1 or at least one of the piston pumps 1. Is led away from the outlet opening 3.4 of the.

As shown in FIGS. 1 and 2, the discharge valve 20 comprises a sealing seat 22, preferably a closed body 24, embodied as a ball, disposed in the discharge opening 5.4 of the pressure chamber 5.2, and A return spring 26 acting on the closure body 24. The return spring is supported at the bottom of the corresponding receiving chamber 28. In view of the fluid flow 3.8, the throttle device 10 of the fluid flow 3.8 behind the discharge valve 20 is provided to reduce noise generation. For this purpose, a receiving chamber 3.6 for the throttle device 10 is provided between the pump cylinder 5 and the cover 3, the receiving chamber having a first face on the end face of the pump cylinder 5 and It is constrained by the second side having a step towards the interior of the cover 3. The accommodating chamber 3.6 is embodied in a substantially circular shape and communicates into the fluid channel 3.2. The throttle device 10 is inserted into the cover 3, as shown in FIG. 2, before fitting the cover 3 to the ledge 5.1 of the pump cylinder 5.

The cover 3 can be manufactured by cutting or deformation in a known manner, and from an economic point of view a large number of parts are provided with a deformation method. The discharge structure is suitably formed because it affects the noise behavior of the piston pump 1. This formation is usually a suitable tapering of the discharge channel in piston pumps known in the art, which tapering forms a throttle action. By this throttle action, a hydraulic low pass filter is formed, which acts positively on the generation of undesirable noise. The behavior of the dynamic viscosity of the brake fluid in the range between 0 ° C and 120 ° C can be seen to be almost constant, and the optimum throttle action is defined for this temperature range. Due to the large fluctuations in the kinematic viscosity of the brake fluid over the required temperature range of -40 ° C to 120 ° C, the throttle loads the parts under compression load of the piston pump 1 and the entire pump drive, especially at low temperatures. The narrowed cross section results in much increased liquid friction at low temperatures, which results in a clearly excessive rise in pump internal pressure, from which the load appears.

As shown in FIGS. 1 to 4, the throttle device 10 of the fluid flow 3.8 comprises a spring member 12, which spring member can be pre-determined with the fluid channels 3, 2. A throttle point 14 having a cross section is formed. In this case, the spring member 12 is embodied as an open ring with two spring legs 12. 1, 12. 2 and is elastically formed in the region of at least one throttle point, so that the open cross section of the throttle point 14 is reduced in pressure It can be set variably according to. According to the invention the first spring leg 12. 1 is provided with an extension, which is embodied as a sealing strap 12.3, which extension covers at least one throttle point 14 and pressures the open cross section of the throttle point 14. Set variable according to the difference. For this reason, embodiments of the present invention are preferably able to adjust their throttle behavior or their open cross section dynamically according to the pressure difference.

In the illustrated embodiment, the extension embodied as the sealing strap 12.3 is embodied shorter than the fluid channel 3.2 so that at the throttle point 14 the minimum open cross section Q _F of the fluid channel 3.2 is independent of the pressure difference. Fixedly predetermined. The minimum open cross section Q _F is optimized for volume flow in a predetermined temperature range, preferably 0 ° C. to 120 ° C., depending on the desired throttle behavior. Due to the temperature variation, the viscosity of the fluid at the predetermined minimum open cross section Q _F of the throttle point 14 and thus the flow resistance changes. By the elastic implementation of the base body of the spring member 12 in the region of the throttle point 14, the throttle point 14 is enlarged so that the free cross section is enlarged or a new free cross section is set. For this reason, the internal pressure of the piston pump 1 preferably does not rise at particularly low temperatures, so that other parts of the piston pump 1 are not damaged. Irrespective of the pressure difference, the maximum open cross section of the throttle point 14 can be predetermined, for example, by the existing receiving chamber 3.6 or the stopper. In the illustrated embodiment, the maximum open cross section of the throttle point 14 moves in the direction 12.4 in which the sealing strap 12.3 unfolds only until the strap end 12.4 contacts the corresponding side wall of the fluid channel 3.2. It can be limited by. The dynamic behavior of the open cross section of the throttle point 14 during pressure differential fluctuations is preferably determined by the selection or setting of the spring characteristics and / or the design of the base body of the spring member 12 and / or the design of the throttle point 14. Can be. The base body of the spring member 12 may for example be made of round wire and / or flat wire and / or made as a stamping part.

As shown in FIG. 2, the receiving chamber 3.6 comprises a support 3.9 in the illustrated embodiment. The base body of the spring member 12 has a sealing strap 12.3 disposed on the first spring leg 12 in contact with the wall of the fluid channel 3.2 and the spring end 12.5 of the second spring leg 12.2 It is inserted into the receiving chamber 3.6 to contact the support 3.9. For this reason, the spring member 12 is preferably arranged in the cover 3 untwisted. As shown in FIG. 2, the predetermined minimum open cross section Q _F of the throttle point 14 having a shape determined by the sealing strap 12.3 and the fluid channel 3.2 of the spring member 12 is dependent on the spring behavior. It is possible to increase the fluid flow (3.2) through the fluid channel (3.2) at the throttle point (14) up to the threshold pressure difference value determined by it. When the pressure difference rises above the threshold pressure difference value, the sealing strap 12.3 unfolds in the direction indicated by the arrow 12.4, thereby increasing the open cross section of the throttle point 14 and the flow rate of the fluid and decreasing the effective pressure difference.

As shown in FIG. 2, when the diameter of the base body of the spring member 12 is made larger than the diameter of the accommodating chamber 3.6, the spring member 12 is inserted into the accommodating chamber 3.6 by preliminary stress. Thereby, the fixed seating of the spring member 12 is made in the accommodation chamber 3.6. Alternatively, if the diameter of the base body of the spring member 12 is made smaller than the diameter of the receiving chamber 28, the spring member 12 is inserted into the receiving chamber 3.3 with radial play. In this case, the base body of the spring member 12 has less spring stiffness than in the embodiment with the larger diameter.

As shown in FIG. 4, the spring members 12 are staggered in the axial direction by a predetermined height h. Because of this, since the spring member 12 is prestressed in the axial direction by the pump cylinder 5 and the cover 3, the sealing strap 12.3 is supported on the floor and the spring member 12 is noiseless or " "Without rattling".

Embodiments of the invention allow for very good NVH-Noise (NVH: Noise, Vibration, Harshness) in a preferred manner. By means of the elastic throttle device, the pressure difference before and after the throttle device in the high viscosity state of the fluid can preferably be kept constant. This reduces the drive output, and the load on the force transmission individual components such as bearings, pistons, high pressure sealing rings and the like. This can be used to reduce costs in suitable designs in future configurations. In addition, by means of the design of the throttle point the throttle behavior or the discharge behavior can preferably be adapted to the function.

3 cover
3.2 Fluid Channel
3.6 Receiving Chamber
3.8 Fluid Flow
3.9 Support
5 pump cylinder
10 throttle gear
12 spring members
12.1, 12.2 spring legs
12.3 Sealing Straps
12.5 Spring End
14 throttle points
20 outlet valve

Claims (10)

A throttle device for fluid flow, comprising a spring member (12) forming a throttle point (14) with an open cross section that can be predetermined with a fluid channel (3), the spring member (12) having two springs It is formed as an open ring with legs 12.1 and 12.2 and is elastically formed in the region of at least one throttle point 14 so that the open cross section of the throttle point 14 can be set variably according to the pressure difference. Throttle device,
The first spring leg 12.1 is provided with an extension, which is embodied as a sealing strap 12.3, which extends to cover the at least one throttle point 14 and according to the pressure difference across the open cross section of the throttle point 14. Throttle device, characterized in that the variable setting. 2. The extension as recited in claim 1, wherein the extension, which is embodied as a sealing strap (12.3), is formed shorter than the fluid channel (3.2), so that the minimum open cross section of the fluid channel (3.2) is fixed in advance at the throttle point (14). Throttle device, characterized in that the losing. 3. The throttle according to claim 2, wherein the minimum open cross section of the fluid channel (3.2) at the throttle point (14) is preferably optimized for volume flow in a predetermined temperature range of 0 ° C to 120 ° C. Device. The throttle device according to any one of claims 1 to 3, wherein the spring member (12) is embodied staggered in the axial direction by a predetermined height (h). 5. Throttle device according to any of the preceding claims, characterized in that the base body of the spring member (12) is formed of round wires and / or flat wires and / or is formed as a stamping part. A piston pump for fluid delivery, comprising a piston, a pump cylinder (5), and a pressure chamber (5.2) disposed between an inlet valve and an outlet valve (20), the pressure chamber being closed by a cover (3), In a piston pump, provided with a fluid flow (3.8), a throttle means (10) of the fluid flow (3.8) is provided behind the discharge valve (20),
Piston pump, characterized in that the throttle means are formed as a throttle device (10) of the fluid flow (3.8) according to any one of the preceding claims. 7. The base body of the spring member 12 is inserted into a receiving chamber 3.6, which is accommodated by a first face of the pump cylinder 5 and a second face in the cover 3. Limited, characterized in that the receiving chamber (3.6) is substantially circular in shape and communicates into the fluid channel (3.2). 8. A piston pump according to claim 7, wherein the receiving chamber (3.6) comprises a support (3.9). 9. The base body of the spring member (12) according to claim 8, wherein the sealing strap (12.3) disposed on the first spring leg (12.1) is in contact with the wall of the fluid channel (3.2). A piston pump, characterized in that it is inserted into the receiving chamber (3.6) such that the spring end (12.5) of 12.2) contacts the support (3.9). 10. The method according to any one of claims 6 to 9, wherein the diameter of the base body of the spring member 12 is made larger than the diameter of the receiving chamber 3.6 so that the spring member 12 is subjected to prestress. Is inserted into the accommodation chamber 3.6 or the diameter of the base body of the spring member 12 is smaller than the diameter of the accommodation chamber 3.6 so that the spring member 12 has radial play and the Piston pump, characterized in that it is inserted into the receiving chamber (3.6).

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