GB2073377A - A flow regulating valve - Google Patents

Abstract

The flow regulating valve consists of a housing (10) and a control slide (31) guided in its bore and which is loaded at both ends by springs (26, 32). It is for formed that it permits flow of the pressure medium from the pump (18) to a load (15) unthrottled whilst in the opposite direction from the load to the reservoir pressure medium is throttled with the aid of the control slide. For that purpose, it has a throttle (38) which, in cooperation with the springs, forms a throttled return flow. Unthrottled flow is via a slide groove (42) copending with port (45). <IMAGE>

Description

SPECIFICATION A flow regulating valve State of the art The invention originates from a flow regulating valve according to the preamble to the main claim. One known flow regulating valve of that kind requires two valves for that operation, for example a non-return valve which blocks the through-flow in one flow direction whilst the flow regulating valve member connected in parallel throttles and in the opposite direction the non-return valve offers no resistance to the discharging pressure medium. A second valve.can also be arranged in the throttle valve member undertaking this function instead of a non-return valve. The disadvantage with both arrangements is that they are of expensive construction.

Advantages of the invention As opposed to this, the flow regulating valve in accordance with the invention comprising the characterising features of the main claim has the advantage that it is of simple construction and is therefore very cheap.

Advantageous further developments and improvements of the flow regulating valve set forth in the main claim are made possible by the measures set forth in the sub-claims.

Drawing Two embodiments of the invention are illustrated in the drawing and are described in detail in the following specification. Fig. 1 shows a first embodiment of a flow regulating valve in longitudinal section, Fig. 2 shows a second embodiment likewise in longitudinal section.

Description of the embodiments In Fig. 1, a valve housing is referenced 10 which has a blind bore 11 into which is screwed in a fluid tight manner a valve insert 12. A bore 13 from which a line 14 leads to a load 15, for example an hydraulic cylinder, issues into the blind bore 11 transversely thereto. From the open end of the blind bore 11, a line 1 6 leads to a multi-way valve 1 7 which is in communication with a pump 1 8 and a tank 19.

The valve insert 1 2 has a stepped bore having a section 21 of large diameter and a section 22 of smaller diameter. Thus, a shoulder 23 is provided against which abuts a displaceable spring plate 24. A spring 26 acts on the plate, the other end of the spring engaging a spring plate 27 which is screwed into the rear portion of the valve insert 1 2. In this way, the pretensioning of the spring 26 can be varied. In its rear portion accommodating the spring plate 27, the valve insert 1 2 is provided with two longitudinal slots 28, 29.

The spring plate 27 is internally hexagonal at 30 for screwing it in.

A control slide 31 is slidingly guided in the bore section 22. The spring 26 on the one hand and a spring 32 on the other hand, which is arranged in a chamber 33 which lies at the end of the bore section 22, act on the control slide. The control slide has a blind bore 35 facing the chamber 33 and into which the spring 32 penetrates. At the base of the blind bore, a throttle bore 36 is arranged which issues into a transverse bore 37 passing through the control slide 31. Coaxially with respect to the throttle bore 36 and proceeding from the transverse bore 37, a second throttle bore 38 also passes through the upper portion of the control slide. It issues into a short blind bore 40 at the portion of the control slide facing the spring plate 24. There the spring plate has a passage 41.An annular groove 42 which does not reach the transverse bore 37, is formed on the control slide radially outside the blind bore.

A plurality of radial bores 44 are formed in the valve insert 1 2 at the level of the housing bore 13, the bores 44 issuing into an annular groove 45 which is formed in the bore section 22. Considerable clearance is provided between the lower portion of the valve insert 1 2 and the blind bore 11.

When the multi-way valve 1 7 is so set that the pump 1 8 delivers pressure medium into the line 16, then this arrives through the hexagonal section 30 in the spring plate 27 and the longitudinal slots 28, 29 into the interior of the valve insert and from there through the passage 41 in the spring plate 24 on the valve member. Then, during flow through the throttle 38, a dynamic pressure is produced by means of which the control slide 31 is moved against the force of the spring 32. After a certain displacement path, the groove 42 in the control slide is connected to the annular groove 45 on the valve insert.

Thus; the pressure medium is guaranteed an unthrottled passage through the line 1 4 to the load 15.

In the reverse direction, the pressure medium needs to be throttled so that the load is not suddenly relieved. Once again, a resistance to through flow is produced at the throttle 38 whereby the pressure generated thereat also arrives through the throttle 36 into the chamber 33 accommodating the spring 32. Thereafter, the control slide 31 is moved towards the spring plate 24 whereupon the communication from the annular groove 45 to the transverse bore 37 is throttled more and more and indeed until a state of equilibrium is reached. The communication to the annular groove 42 is then interrupted.

The flow of pressure medium from the load 1 5 to the line 1 6 is throttled even more thereby and the pressure medium flows slowly to the reservoir 1 9.

Once again, the embodiment according to Fig. 2 has a similar valve insert as previously which is now referenced 50. Like parts as in the previous embodiment arc insofar as is necessary-provided with the same reference numerals. Once again, the spring plate 27 and a spring plate 51 corresponding to the spring plate 24 and having a plurality of inclined extending through bores 52, are arranged in the bore section 21.The spring plate is arranged in an annular housing insert the diameter of which is less than that of the bore section 21.

A control slide 56 is slidingly guided in the bore section 22 and its mushroom head 57 engages the conical end 51' of the spring plate 51 under the force of the spring 32.

Once again, a blind bore 59 is formed in the rear portion of the control slide, from which a blind bore 60 of narrow diameter proceeds and extends up to the head 57. From there, a transverse bore 61 extends and which issues outwardly behind the head 57. A plurality of radial bores 63 issue into the bore section 22 wherein the chamber between the bore sections 21 and 22 is referenced 64.

During flow from the line 1 6 to the line 14 the control slide engaging the spring plate 51 is pushed by pressure medium against the force of the spring 32 so that the pressure medium can flow past the head 57 through the transverse bore 63 to the load unthrottled.

In the reverse direction of flow, the pressure medium must be throttled once again. The compression spring 32 urges the head 57 against the spring plate 57. In so doing, the head 57, together with the insert 34, forms a throttle gap 65. The pressure in the chamber 64 arrives through the bores 61 and 60 in the chamber 33 whereupon the control slide is permanently forced against the spring plate 51. Due to the pressures in the chamber 64 and the chamber 33, the control slide is then pushed against the force of the spring 26 so far that its control edge 66 closes the transverse bore 63 to such an extent that a condition of equilibriuni is produced between the spring force and the fluid force.

According to the throttling effect, the housing insert 54 can be provided with a more or less large inner diameter.

Claims (8)

1. A flow regulating valve comprising a control slide displaceable against the force of a spring by pressure medium flowing through it and a throttle location which controls the pressure medium flow delivered from a pressure medium source through a multi-way valve, unthrottled to a load whereas in the reverse direction of the pressure medium flow discharged by the load it flows away to the reservoir throttled, characterised in that, both the throttling and the free through flow of the pressure medium take place only with the aid of the control slide.

2. A valve according to claim 1 characterised in that the control slide is loaded at both ends by springs and has two throttle bores which lead to the two opposite chambers accommodating the springs and proceed from a transverse bore passing through the control slide and which is in communication with the load side through recesses formed in the valve housing.

3. A valve according to claim 1 and/or 2 characterised in that an annular groove is formed at one end of the control slide, through which, in cooperation with the recesses, an unthrottled flow from the load to the reservoir takes place.

4. A valve according to one of claims 1 to 3 characterised in that the control slide has a widened portion which, in cooperation with the wall of the valve housing, forms a throttle location.

5. A valve according to one of claims 1 to 4 characterised in that a duct communication to a chamber is provided in the control slide and through which the throttle pressure in the said chamber which also accommodates the spring, is propagated.

6. A valve according to one of claims 1 to 5 characterised in that the throttle gap is produced by an insert portion in cooperation with the widened portion of the control slide.

7. A valve according to one of claims 1 to 6 characterised in that the control slide is arranged in an insert portion which is located in a valve housing.

8. A flow regulating valve substantially as herein described with reference to Fig. 1 or Fig. 2 of the accompanying drawings.