KR20110002425A - Pressure regulating valve for an automatic gearbox in vehicle - Google Patents

Abstract

PURPOSE: A pressure control valve for an automatic transmission of a vehicle is provided to reduce the manufacturing process and ensure an accurate operation. CONSTITUTION: A pressure control valve for an automatic transmission of a vehicle comprises a housing(12) and a slide valve. The housing comprises supply connectors(46), adjustment connectors(52) and return connectors(48). One or more groups composed of the supply connectors and the return connectors are connected to one or more control openings within ta cylindrical guide surface(18) of the housing. The control openings are extended to a limited length in the circumferential direction of the guide surface and cooperate with allocated control edges(25,27) of the slide valve.

Description

Pressure regulating valve for an automatic gearbox in vehicle

The present invention relates to a pressure regulating valve according to the preamble of claim 1.

In modern automatic transmissions in vehicles, hydraulically actuated clutches are used to shift gears. In order to carry out this shift process without impact and without operator recognition, the hydraulic pressure of the clutch must be adjusted very precisely according to a given pressure ramp. An electromagnetically actuated pressure regulating valve is used to regulate this pressure ramp. The pressure level required for the shifting process is provided by the regulating connection of the pressure regulating valve and is achieved by a so-called "pressure gauge" integrated in the pressure regulating valve. In this pressure gauge, the variable force of the electromagnetic actuating device is in equilibrium with the hydraulic force and the compression spring force according to the regulating pressure. Examples of such pressure regulating valves are described in DE 199 07 275 C1. DE 10 2007 026 831 B3 and WO 2008/039500 A1 also relate to similar valves.

It is an object of the present invention to provide a pressure regulating valve which can be manufactured simply and inexpensively and which operates accurately.

This object is achieved by a pressure regulating valve having the features of claim 1. Preferred refinements of the invention are given in the dependent claims. Key features of the invention are set forth in the following description and the drawings. These features may be important in the present invention, alone or in multiple combinations, and are not discussed in detail in this regard.

The pressure regulating valve according to the invention has the advantage that the leakage between the slide valve and the housing is relatively small, for which the guide play of the slide valve in the housing does not have to be reduced. This is particularly achieved by reducing the width of the leakage current by the limited circumferential length of the control opening. The pressure regulating valve can thus be operated very accurately. In addition, the pressure source providing the pressure may have a lower feed rate. No particularly small play between the slide valve and the housing is also required, so the manufacturing cost is kept small. This applies in particular when the housing and / or slide valve are produced by a molding method, such as injection molding.

In terms of minimizing leakage, the control opening preferably has a cross-sectional area of at most 2.5 mm 2, preferably 0.2 to 1.8 mm 2. Less leakage is achieved by this cross section even when the play between the slide valve and the housing is relatively large. If the value is smaller, the manufacturability is limited and the maximum flow rate is reduced.

Preferably, the control opening has a round cross section, in particular a circular cross section. It can be produced simply and inexpensively.

With regard to minimizing leakage, the cross section of the control opening is polygonal, in particular the triangular cross section is preferred when the triangular peak of the control opening is directed towards the control edge of the slide valve, which is assigned to the peak. This extends the distance of a significant amount of leakage current, which reduces the leakage as a whole.

In order to counteract the lateral forces of the slide valve and the asymmetrical play between the slide valve and the housing, a plurality of control openings arranged evenly distributed in the circumferential direction of the guide surface can be connected to the supply connection. This reduces or eliminates unwanted hysteresis of the pressure-current-characteristic curve of the pressure regulating valve. The two control openings may be arranged offset 180 degrees, for example, or the three control openings may be arranged offset 120 degrees, or the four control openings may be arranged offset 90 degrees. It is optimal to implement only two opposingly arranged control openings, since in this case the cross section of the control opening and the cross section of the corresponding channel do not have to be chosen too small, so that the opening can be made well. In addition, two oppositely arranged transverse channels can be produced with relatively low complexity with an injection molding tool. Similar advantages can be achieved when a plurality of control openings uniformly distributed in the circumferential direction of the guide surface are connected to the return connection.

It is also proposed that the control opening extends radially and forms a radially inner end of the channel through the housing. This is a simple way to save money in manufacturing technology. This applies when the channel extends radially, ie substantially perpendicular to the longitudinal axis of the housing.

With regard to the guide play between the slide valve and the guide surface of the housing, values of 0.02 to 0.15 mm, preferably 0.03 to 0.1 mm are proposed. If the clearance is smaller, the sensitivity to contamination by the particles is too large and leakage is undesirably increased when the guide clearance is larger. The range from 0.03 to 0.1 mm is a value that can be particularly well realized with inexpensive manufacturing methods, such as injection molding.

Another preferred embodiment of the pressure regulating valve according to the invention is characterized in that the control edge is formed with an end edge on the end face of the slide valve having a simple cylindrical shape. This makes the manufacture of the pressure regulating valve much simpler, which saves cost. This applies in the use of a slide valve having a simple cylindrical shape, i.e. without a step, neck or circumferentially extending groove.

In a pressure regulating valve in which a supply connection and a return connection are connected to each of at least one control opening cooperating with each end edge on each end face of the slide valve to form a pressure compensating slide valve. The pressure chambers confined by the end face may be connected to each other for fluid communication. This can be realized, in particular simply, by the arrangement of at least one groove extending axially in the guide face of the housing. Alternatively or additionally the fluid connection may be provided by a channel in the slide valve, for example by an eccentric longitudinal bore.

Embodiments of the present invention are described below with reference to the accompanying drawings.

According to the present invention, there is provided a pressure regulating valve which can be manufactured simply and inexpensively and which operates accurately.

1 is a partial longitudinal sectional view of a first embodiment of a pressure regulating valve;
FIG. 2 is a sectional view along line II-II of FIG. 1;
3 shows an area of the pressure regulating valve of FIG. 1.
4 shows an alternative embodiment of a pressure regulating valve similar to FIG. 3.

In FIG. 1 the pressure regulating valve is shown at 10. The pressure regulating valve comprises a housing 12 which has a stepped outer contour in the axial direction. The housing is provided with a step bore 14 extending longitudinally, the bore comprising a guide section 16 having a constant diameter. The guide section 16 has a cylindrical guide surface 18. In the guide section 16 of the step bore 14 a simple cylindrical slide valve 20 is arranged, which is guided by the guide surface 18. The outer face of the slide valve 20 is shown at 22, in FIG. 1 the left end face is shown at 24 and in FIG. 1 the right end face is shown at 26. A control edge 25 is formed between the end face 24 and the outer face 22, and a control edge 27 is formed between the end face 26 and the outer face 22. The two control edges 25, 27 extend radially.

A compression spring 28 contacts the left end face 24 of FIG. 1, the other end of which is supported by the shoulder of the step bore 14 in the housing 12. A coupling pin 30 acts on the right end face 26 of FIG. 1 of the slide valve 20, which is guided in a fluid sealing manner within the guide-and seal 32. The armature 34 of the electromagnetic actuating device 36 acts on the end of the coupling pin 30 which is remote from the slide valve 20. The electromagnetic actuating device is flanged to the housing 12 of the pressure regulating valve 10.

In the region of FIG. 1 left end of the slide valve 20 in the region of the guide section 16, two channels 38a, 38b are provided which are opposed, extend radially and penetrate the housing 12. The inlet of each channel 38a, 38b leading to the guide surface 18 forms a control opening 40a or 40b. Similarly, in the right end region of FIG. 1 of the slave valve 20, a pair of channels 42a, 42b disposed opposite each other and extending radially through the housing 12 is provided. The channel inlet leading to the guide surface 18 forms control openings 44a and 44b.

The two channels 42a, 42b are connected to a supply connection 46, which is connected, for example, to the pressure side of a hydraulic pump, not shown. Two channels 38a, 38b are connected to the return connection 48, which is connected, for example, to the low pressure side of the hydraulic pump. At the left end of FIG. 1, the housing 12 has an adjustment pressure opening 50, which is connected to the adjustment connection 52. In order to operate the clutch for gear shifting in a vehicle, for example, if the vehicle automatic transmission is equipped with a pressure regulating valve 10, the hydraulic clutch operation can be made by the regulating connection 52, and the pressure is applied to the clutch via the hydraulic amplifier. Works.

O-rings 54 are arranged in the circumferential grooves on the outer side of the pressure regulating valve 10 for sealing the supply connection 46, the return connection 48 and the adjustment connection 52. In particular, the pressure chamber 56 is limited by the left end face 24 of FIG. 1, while the pressure chamber 58 is limited by the right end face 26 of FIG. 1. As shown in FIG. 2, the two pressure chambers 56, 58 are fluidized by two grooves 60a, 60b axially extending and opposed in the guide surface 18 of the step bore 14. Are connected to each other so that In addition, as shown in FIG. 3, the control opening 40a has a circular cross section. The other control openings 40b, 44a, 44b likewise have a circular cross section.

The cross sectional area of the control openings 40a, 40b, 44a, 44b is 1.0 mm 2 in this embodiment, may have different values in other embodiments, and is up to 2.5 mm 2. Preferably the cross sectional area is from 0.2 to 1.8 mm 2. 3, it can be seen that the control opening 40a extends over a limited distance in the circumferential direction of the guide surface 18, that is, over the diameter of the control opening 40a. The slide valve 20 is guided with a play 62 (FIG. 3) in the guide section 16, which play is approximately 0.06 mm in this embodiment. In another embodiment, not shown, the play may have a different value, but should be 0.02 to 0.15 mm, more preferably 0.03 to 0.1 mm.

The pressure regulating valve 10 operates as follows: In order to regulate the specific pressure level to the regulating connection 52, current is supplied to the electromagnetic actuating device 36 in a specific manner, whereby the coupling pin 30 is applied. It is pressed by the specific force to the slide valve 20 (arrow 64 in FIG. 1). The force generated by the hydraulic pressure in the pressure chamber 58 and by the cross section (unreferenced) of the coupling pin 30 towards the slide valve 20 is opposed to the force (arrow 64) according to the arrow 66. do. The force difference acts on the slide valve 20 against the force of the compression spring 28. The same pressure exists in the two pressure chambers 56, 58 due to the connection by the grooves 60a, 60b. That is, the slide valve 20 is pressure compensated.

As the pressure of the regulating connection 52 decreases, the hydraulic force (arrow 66) on the coupling pin 30 correspondingly acts in the same direction with respect to the pressure of the pressure chamber 58 and the compression spring 28. . This causes the slide valve 20 to move to the left in FIG. 1, so that the two control openings 44a, 44b are close to or come out of the control edge 27 assigned to them and thus pressurized hydraulic pressure. The fluid may flow further into the pressure chamber 58. The pressure thus increases in the pressure chamber 58 and beyond the grooves 60a, 60b in the pressure chamber 56 and correspondingly in the regulating connection 52.

In this way, the slide valve 20 forms a pressure scale that allows a specific pressure level to be automatically adjusted at the regulating connection 52 in response to the current supply to the electromagnetic actuating device 36. The too high pressure of the regulating connection 52 is reduced by the proper movement of the slide valve 20 to the right in FIG. 1 and by the discharge of hydraulic fluid to the return connection 48. This is accomplished by the control edge 25 approaching the control openings 40a and 40b or opening the control openings 40a and 40b when the slide valve 20 moves to the right.

In the pressure regulating valve 10 shown, there is a relatively small leakage from the pressure chamber 56 into the control opening 40 and through the guide play 62 from the control opening 44 into the pressure chamber 58. The reason is that the width of the leakage current (as viewed in the circumferential direction of the slide valve 20) shown by the arrow 68 in FIG. 3 is relatively small. Also, as can be seen from the length of arrow 68, the flow path of the large area of the control opening 40a (which applies equally to other control openings) is relatively long, which is a low pressure gradient which results in less leakage. cause a pressure gradient. Relatively little leakage is achieved by the control openings 40, 44 having a relatively small cross section.

In an alternative embodiment in which members and regions shown in FIG. 4 and functioning the same as in the figure have the same reference numerals, the control opening 40a (and other control openings) does not have a circular cross section, but is polygonal, ie triangular. Have a cross section; The peak of the triangular cross section is to the right in the position of the slide valve 20 shown in FIG. 4, ie towards the control edge 27. Thus, the leak arrow 68 is longer in the side region of the control opening 40a, which further reduces leakage. This leakage reduction is achieved even if the guide play 62 is not particularly small.

10 pressure regulating valve
12 housing
18 guide surface
20 slide valve
40, 44 control opening
46 supply connection
48 return connections
52 adjustable connections

Claims (11)

In particular, a pressure regulating valve 10 for an automatic transmission of a vehicle, comprising a housing 12 and a slide valve 20 guided to the housing 12, and at least one supply connection 46 to the housing 12. In a pressure regulating valve, provided with a regulating connection 52 and a return connection 48,
At least one group of the supply contacts 46 and the return contacts 48 comprises at least one control opening 40 in the cylindrical guide surface 18 of the housing 12 which guides the slide valve 20. 44, the control openings 40, 44 extend over a limited distance in the circumferential direction of the guide surface 18, and control edge 25 of the slide valve 20 assigned to the control opening. And 27), wherein the control openings (40, 44) have a cross-sectional area of at most 2.5 mm 2, preferably 0.2 to 1.8 mm 2. 2. A pressure regulating valve for an automatic transmission according to claim 1, characterized in that the at least one control opening (40a) has a round cross section, in particular a circular cross section. 2. The pressure regulating valve of claim 1, wherein the at least one control opening has a polygon, in particular a triangular cross section. 4. The supply connection portion 46 according to any one of claims 1 to 3, characterized in that a plurality of control openings 44 uniformly distributed in the circumferential direction of the guide surface 18 are connected to the supply connecting portion 46. Pressure regulating valve for automatic transmission of vehicles. The method according to any one of claims 1 to 4, characterized in that a plurality of control openings (40) which are evenly distributed in the circumferential direction of the guide surface (18) are connected to the return connection portion (48). Pressure regulating valve for automatic transmission of vehicles. 6. The vehicle according to claim 1, wherein the control openings 40, 44 form radially inward ends of the channels 38, 42 through the housing 12. 7. Pressure regulating valve for automatic transmission. 7. A pressure regulating valve for an automatic transmission as claimed in claim 6, wherein said channels (38, 42) extend radially. 8. A guide play 62 as claimed in any one of the preceding claims, wherein between 0.02 and 0.15 mm, preferably 0.03 and 0.1 mm, a gap is provided between the slide valve 20 and the guide surface 18. Pressure control valve for an automatic transmission of a vehicle, characterized in that. 9. The control edge according to any one of claims 1 to 8, wherein the control edges (25, 27) are formed by end edges on the end faces (24, 26) of the slide valve (20), the slide valve Pressure regulating valve for an automatic transmission of a vehicle, characterized in that it has a simple cylinder form. 10. The supply connection (46) and the return connection (48) are each connected to at least one control opening (40, 44), the control openings of the slide valve (20). Pressure chambers 56, 58 cooperating with respective end edges 25, 27 at respective end faces 24, 26 and constrained by the end faces 24, 26 of the slide valve 20. Pressure control valve for an automatic transmission of a vehicle, characterized in that the fluid is connected to each other through. 11. A pressure regulating valve for an automatic transmission as claimed in claim 10, characterized in that the guide surface (18) is provided with at least one groove (60) extending axially.

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