CN1761830A - Non-return valve - Google Patents

Abstract

A non-return valve is disclosed, comprising a sealing piston (4), pre-tensioned against a valve seat (18) in the rest position in a valve housing (8), which is produced by means of a plastic injection moulding method.

Description

check valve

technical field

The invention relates to a non-return valve according to the preamble of claim 1 .

Background technique

Check valves are used to block the flow of pressurized oil in one direction and to allow volume flow in the opposite direction.

Such a non-return valve is disclosed in the applicant's document RD 20 395/10.95. In this respect, the flow-through metal valve seat piston is located in the valve housing and is pretensioned against the valve seat in the initial position, so that the pressure oil connection between the two working connections in the flow direction is blocked.

The disadvantage of this known solution is that the machining effort for producing the metal valve-seat piston is very high.

Furthermore, this known solution has the disadvantage of a severe tendency to leak.

A further disadvantage is that the metal seated piston is very heavy and therefore the non-return valve exhibits a rather sluggish opening and closing ability.

Contents of the invention

The object of the present invention is to provide a non-return valve which can eliminate the above-mentioned disadvantages and which can be produced cost-effectively.

This object is achieved by a non-return valve having the features of claim 1 .

The seat piston of the non-return valve according to the invention is produced by plastic injection molding. This solution has the advantage that the valve seat piston according to the invention can be produced with simple and cost-effective manufacturing technology. Furthermore, the plastic surface of the valve seat piston according to the invention is relatively soft, so that a high degree of tightness can be ensured. Furthermore, the valve seat piston according to the invention is characterized by a very low weight, whereby the non-return valve exhibits a sensitive opening and closing capability.

The preferred plastic is Poly-Ether-Ether-Keton (PEEK), and it is best to add 30% carbon fiber in order to improve the rigidity of the valve seat piston.

The valve seat is guided on the discharge side of the piston, wherein play is introduced on its outer circumference to reduce hysteresis. Between the gaps, axial webs preferably remain, the guide surfaces of which are wetted by the pressure oil in the spring chamber and thus allow optimum guidance of the valve seat piston. In one embodiment, six gaps have six interposed webs.

In the open position, pressurized oil can flow into the spring chamber through the star hole. To improve the guidance of the valve seat piston and for reinforcement, guide projections can be formed between the bores of the star bore. The guide bead is preferably triangular in shape and conical in the direction of the pressure build-up, wherein its axial length preferably corresponds to the inner diameter of the bore. The inner diameter and number of holes are selected according to the respective optimum flow cross-section. Preferably there are four holes.

To avoid swirling of the pressurized oil flow in the open position, the seat piston can have an inflow cone on the input side. The inflow cone can have a rounded or hemispherical top.

In a preferred embodiment, the spring for pretensioning the valve seat piston is supported in the initial position on a spring seat likewise made of plastic. The spring seat preferably has at least one radial sealing lip on its outer circumference, so that the spring chamber is hermetically closed. Likewise, at least one sealing lip can be formed on the end face of the spring seat. A particularly high degree of tightness can be achieved if the radial sealing lip is arranged counter to the pressure build-up direction and the end-face sealing lip is arranged in the pressure build-up direction.

Further advantageous embodiments are the subject-matter of other sub-claims.

Description of drawings

A preferred embodiment of the invention will be described in detail below with the aid of the drawings. in:

Figure 1 shows a side view of an embodiment of a one-way valve according to the present invention; and

FIG. 2 shows a longitudinal section through the non-return valve of FIG. 1 .

Detailed ways

1 and 2 show a side view and an enlarged longitudinal section with a through-flow valve seat piston 4 in a longitudinal bore 6 of a valve housing 8 of a preferred embodiment of a direct control check valve 2 according to the invention. . The longitudinal hole 6 extends between the coaxial connection hole 10 for connecting the working connection pipe A on the input side and the coaxial connection hole 12 of the connecting plate 14 closing the longitudinal hole 6 of the working connection pipe B on the discharge side. The valve seat piston 4 is pretensioned against the valve seat 18 in its initial position by a spring 16 . The spring 16 is arranged in a spring chamber 20 and bears on a spring seat 22 in the longitudinal bore 6 . In this respect, the spring sinks into the receiving bore 24 of the valve seat piston 4 ( FIG. 2 ) and acts on the annular bottom surface 26 of the receiving bore 24 .

The valve seat piston 4 is produced according to the invention by injection molding. It is made of plastic and can be reinforced with carbon fiber. Poly-Ether-Ether-Keton (PEEK) is preferably selected as plastic and reinforced with 30% carbon fibers. The seat piston 4 is designed as a hollow piston, wherein the receiving bore 24 tapers radially in the direction of the inflow side 68 of the seat piston 4 . The bore 54 of the star-shaped bore 52 opens into this conical region 70 . In the open position, pressurized oil thus passes through the valve seat 18 from the bore 54 into the valve seat piston 4 and into the spring chamber 20 on the return chamber side. To improve the flow behavior, the bore 54 opens obliquely into the conical region 70 in the direction of the pressure build-up. The shape and number of holes 54 are selected such that the flow cross-section of holes 54 is optimized. There are preferably four holes 54 .

In order to homogenize the pressurized oil flow, an inflow cone 56 is formed on the inflow side 68 of the valve seat piston 4 . The inflow cone 56 merges into a hemispherical top 64 , wherein the peripheral surface 72 of the top 64 is arranged steeper than the peripheral surface of the inflow cone 56 .

The valve seat piston 4 is guided radially on the discharge side of the longitudinal bore 6 , wherein, in order to avoid one-sided guidance of the valve seat piston 4 in the longitudinal bore 6 and thus reduce hysteresis, there is a large amount of radial play 48 in its outer circumference 46 , The valve seat piston 4 is thus guided on the bottom 76 of the gap 48 via the individual axial webs 50 and the narrow annular bundle 62 , which separate the gaps 48 from one another.

The pocket gap 48 is open towards the spring chamber 20 and extends finger-like in the direction of the inflow cone 56 . The number of gaps 48 is optimized taking into account the width of the guide surface 66 on the circumferential side of the web 50 . Preferably six gaps 48 have six webs 50 .

The annular beam 62 merges countercurrently in the direction of the inflow cone 56 into the axially triangular guide bead 58 . Guide lugs 58 extend between bores 54 and taper in the direction of inflow cone 56 . In this respect, the axial length of the guide projection 58 is preferably selected such that it corresponds substantially to the inner diameter of the bore 54 . In the region of the guide bead 58 , the valve seat piston 4 has the same outer diameter as in the region of the annular beam 62 and in the region of the web 50 , so that the valve seat piston 4 passes the guide bead 58 in the longitudinal bore 6 It is likewise guided, and thus the axial guide length is extended correspondingly to the axial extension of the guide projection 58 . Furthermore, by arranging the guide lugs 58 between the bores 54 , the region of the valve seat piston 4 which is structurally weak due to the bores 54 is reinforced.

The spring seat 22 is made of plastic, which is preferably softer than the plastic of the valve seat piston 4 . The spring seat fits into the radial return step 28 of the longitudinal bore 8 and is axially fixed in its position by contact with the connecting plate 14 . The axial length of the reset step 28 is selected such that the opposite surfaces 30, 32 of the connecting plate 14 and the valve housing 8 are at a distance from each other in the installed state, and the connecting plate 14 is only in contact with the spring seat 22, thereby pressing the spring seat towards The shoulder 74 of the step 28 is reset. In order to be able to discharge pressurized oil from the spring chamber 20 , a through-opening 34 is formed in the spring seat 22 coaxially to the longitudinal bore 6 of the valve housing 8 and to the connecting bore 12 of the connecting plate 14 .

On the outer circumference 42 of the spring seat 22 there is a sealing lip 36 for sealing the spring chamber 20 against the web 14 . The sealing lips 36 run parallel to one another and are formed by an annular groove 38 . The sealing lip 36 runs obliquely to the longitudinal axis of the longitudinal bore 6 , wherein the sealing lip is mounted in the direction of the valve seat 18 against the direction of the pressure build-up as seen from the groove bottom 60 of the annular groove 38 . This oblique profile in combination with soft plastic has the advantage that the sealing lip 36 is automatically erected or installed by the pressure oil and is thus pressed against the inner circumference 40 of the return step 32 of the longitudinal bore 6 . To seal the discharge-side connection hole 12 of the connection plate 14, the end face has at least one sealing lip 44, which is inclined to the longitudinal hole 6, but is arranged opposite to the radial sealing lip 36 in the pressure building direction, so that the pressure of the discharge pressure oil can be Stand it up or mount it.

The manufacturing of the valve seat piston 4 by plastic injection molding significantly reduces the processing effort and thus makes it possible to manufacture the valve seat piston 4 cost-effectively and quickly.

Furthermore, contaminants present in the pressurized oil and deposited, for example, on the valve seat 18 can be pressed into the valve seat piston 4 by the rather soft plastic surface of the valve seat piston 4 , resulting in a high degree of tightness.

Furthermore, the use of plastic according to the invention for the valve seat piston 4 can be significantly lighter than known metal valve seat pistons, so that the non-return valve 4 according to the invention exhibits an improved opening and closing capability. This opening and closing capability is further improved by the gap 48 on the outer circumference 46 of the valve seat piston 4 , wherein the axial guide length of the connecting piece 50 of the valve seat piston 4 is extended by the guide projection 58 . Furthermore, according to the invention, the opening and closing capacity of the non-return valve 2 is improved by the inflow cone 56 , since an optimal flow of pressurized oil into the valve seat piston 4 and through the valve seat 18 in the open state results in an improved drainage.

It goes without saying that although the above-mentioned embodiment describes a check valve with two axially working connecting pipes, the valve seat piston 4 according to the present invention can also be operated with one axially and one radially. Used as a check valve for connecting pipes.

A non-return valve is known with a valve seat piston which is pretensioned against a valve seat in an initial position in a valve housing and which is produced by plastic injection molding.

reference symbol

2 check valve

4 Valve seat piston

6 longitudinal holes

8 Valve housing

10 connection holes

12 connection holes

14 connecting plate

16 springs

18 seat

20 spring chamber

22 spring seat

24 receiving holes

26 Bottom

28 reset steps

30 surface

32 surface

34 through hole

36 sealing lip

38 Annular groove

40 inner circumference

42 outer circumference

44 sealing lip

46 outer circumference

48 Clearance

50 connecting pieces

52 star hole

54 holes

56 inflow cone

58 guide protrusion

60 Groove bottom

62 ring beam

64 top

66 guide surface

68 Inflow side

70 tapered part

72 Circumferential surface

74 Raised shoulders

76 Bottom

Claims (14)

1. One-way valve with a hollow seated piston (4), which is located in the valve housing (8) and pretensioned to the valve seat (18) by a spring (16) at the initial position, thereby controlling the valve seat (18) at the initial position Pressure oil connection between two working connections (A, B) in flow direction, characterized in that the valve seat piston (4) is produced by plastic injection molding. 2. The non-return valve as claimed in claim 1, wherein the valve seat piston (4) is made of PEEK plastic. 3. The non-return valve according to claim 1 or 2, wherein the seat piston (4) is reinforced with 30% carbon fiber. 4. The one-way valve according to one of the preceding claims, wherein the valve seat piston (4) has a large amount of clearance (48) on the outer circumference (46), so that the valve seat piston (4) passes through the clearance (46) Axial webs (50) spaced apart from each other are guided in the longitudinal bore (6). 5. Check valve according to one of the preceding claims, wherein the valve seat piston (4) has a star-shaped hole (52), through which the hole (54) allows the pressure oil in the open position to flow into the spring In the chamber (20). 6. The non-return valve as claimed in claim 4 or 5, wherein there are six gaps (48) and four holes (54). 7. The non-return valve as claimed in claim 5 or 6, wherein guide projections (58) are formed between the bores (54). 8. The non-return valve as claimed in claim 7, wherein the guide projection (58) is triangular in shape and conical in the direction of inflow. 9. The non-return valve as claimed in claim 7 or 8, wherein the guide projections (58) each have an axial length which approximately corresponds to the inner diameter of the bore (54). 10. The non-return valve as claimed in claim 1, wherein the seat piston (4) has an inflow cone (56). 11. The non-return valve as claimed in claim 10, wherein the inflow cone (56) has a rounded top (62). 12. The non-return valve as claimed in claim 1, wherein the spring (16) is supported by a plastic spring seat (14) in the valve housing (8). 13. The non-return valve according to claim 12, wherein the spring seat (14) has at least one sealing lip (36, 44) on its outer circumference (42) and/or on its end face. 14. The non-return valve according to claim 13, wherein the radial sealing lip (36) is mounted against the direction of pressure build-up, and the end-face sealing lip (44) is mounted in the direction of pressure build-up.

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