JP2852476B2 - Drainage pump control mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control mechanism for an oil discharge pump, particularly a case pump provided with a case bore perpendicular to a drive shaft of a vane pump and through which a flow control piston is guided. The case bore additionally has a throttle mechanism coupled to an outlet connected to the load side. Further, the outside front surface of the flow control piston receives an outlet pressure and a spring force acting behind the throttle mechanism. On the other hand, the inside front face of the flow control piston facing the throttle mechanism receives the internal pump pressure.
The internal pump pressure in this case means the pressure applied to the throttle mechanism. The flow control piston forms a connection to the inlet passage of the pressure chamber of the pump in response to the differential pressure acting on the front face on both sides generated by the throttle mechanism. Therefore, the feed piston controls so as to increase the flow component to the suction side of the pump as the pump rotation speed increases. By this processing, the usage flow rate available on the load side is kept constant or reduced.

[0002]

2. Description of the Related Art A control mechanism according to the preamble of claim 1 of the present invention is already known from U.S. Pat. No. 4,131,161. Here, a control pin that extends into the throttle bore and has a cylindrical portion and a conical portion is used as a part of the throttle mechanism. Shifting the flow control piston changes the diameter of the control pin, which results in a ring throttle with a varying cross-sectional area to the outlet. Therefore, the course of the flow characteristics is determined by selecting the shape of the control pin.

[0003]

However, such a throttle mechanism operated by a control pin is not suitable for mass production, and therefore cannot obtain exactly the same characteristics. The variation width is quite large. Thus, for example, if the control pin is eccentric within the throttle bore, it may tilt to one side only. When this happens, the valve piston remains down holding the control pin.

Further, it is difficult to accurately maintain the play in the radial direction between the control pin and the throttle bore, or to accurately adjust the axial position of the case bore to the starting point of the control pin cone. Also, when a large flow rate is required, the diameter of the control pin is reduced, and therefore, the control pin may bend.

Furthermore, this known control mechanism has the characteristic that, when the rotational speed is the same, the opening stroke of the flow control piston decreases with an increase in the operating pressure, so that the change in the throttle cross-sectional area accordingly. Smaller. Therefore, its characteristics change with pressure. However, there is a demand for a flow characteristic that is as independent of pressure as possible.

An object of the present invention is to provide a control mechanism capable of obtaining a feed rate which is as independent of pressure as possible over the entire rotational speed range with a simple and thus reliable operation structure. In this case, it is desirable that the throttle mechanism used in the control mechanism can change the feed flow rate characteristics variously by a simple method.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and this problem is solved by the features of claim 1. Claims 2 to 6 include preferred embodiments of the present invention.

The throttle mechanism provided in the case bore of the flow control piston includes a throttle sleeve fixedly mounted on a screw body, an adjusting shell capable of shifting on the throttle sleeve against a spring force, and a casing surrounding the adjusting shell. It is made of a tubular body integral with the body. The adjusting shell also controls a variable passage crossing to an outlet on the throttle sleeve along its shift path. Furthermore, the tubular body forms a variable ring gap with the component shell, which constitutes the connection from the pump to the passage crossing. In this case, the height of the pressure in the ring gap is determined by the movement of the adjusting shell and the variable passage crossings controlled thereby. The entire feed flow rate flows through this variable passage crossing. The passage crossing is dimensioned such that the residual crossing remains open after the end of the control stroke. The front of the throttle sleeve is restricted by the inside front of the flow control piston, passing the pump pressure and
It also faces the chamber leading to the pump inlet (control bore). The height of the differential pressure behind the ring gap in the chamber is a measure for the position of the control piston and the magnitude of the feed flow component controlled with respect to the inlet. According to claim 2, the throttle mechanism is provided with a second fixed crossing port on the front side of the throttle sleeve in addition to the variable crossing port. In this case, the variable crossing may be relatively small, since the fixed crossing is always kept as a residual crossing.

The above two embodiments have the advantage that the manufacture is simple and the operation is reliable. The passage crossing can be easily tuned to the load to be supplied. This tuning is performed by changing the cross-sectional area of the throttle sleeve or the spring force acting on the adjusting shell.

According to claim 3, the variable passage crossing is configured as a throttle bore in a throttle sleeve,
This cooperates with the control shell and the control edge. Such a configuration is suitable for those having a relatively small load flow rate.

According to claim 4, the free end of the throttle sleeve is designed as a cone, which, together with the front edge of the adjusting shell, constitutes a variable first passage crossing. In order to introduce an oil flow, the adjusting shell is further provided with a flow opening. In this configuration, the variable ring cross section is relatively large, so that it is suitable for a large load flow rate.

According to a fifth aspect, a threaded tubular body having a plurality of through holes is provided in the region of the pump inlet passage, through which the connection from the inlet passage to the ring gap is formed. . In this way, a large flow rate is obtained in the throttle mechanism. According to claim 6, the ring gap is formed by the inner curved portion of the tubular body and the outwardly facing foot-like flange of the adjusting shell. The inner curved portion and the flange face each other at the start position.

According to claim 7, the throttle mechanism is configured as a screw-in type cartridge. Thus, it is possible to change the flow characteristics only by replacing the cartridge.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example of a vane pump to which the present invention is applied, FIG. 2 is an enlarged partial sectional view taken along the line AA of FIG. FIG. 9 is a partial sectional view of a throttle mechanism showing another embodiment of the present invention.

In FIG. 1, a pump case 1 and a lid 2
, A drive shaft 3 is supported. The drive shaft 3 holds the rotor 4 via wedge notches in the usual way. A radially moving wing 5 is guided in the radial slit of the rotor 4 and slides along a curved ring 6. During operation of the pump, the pressure plate 7 is supported by a pump package consisting of the rotor 4, the wing 5 and the curved ring 6. The pressure plate 7, the curved ring 6, and the lid 2, which also acts as a pressure technique, are aligned with each other by pins 8. The pressure plate 7 has a notch with a pressure hole 10. In the area of the pressure hole 10 is the pressure zone of the pump. An invisible feed chamber between the wing 5, the rotor 4 and the curved ring 6 is connected to the inlet 12 via a partial ring-shaped space 11. The suction port 12 is open to an inlet passage 13 communicating with the partial ring-shaped vacant space 11. The oil sent to the pressure side by the wing 5 enters the suction passage 35 through the pressure hole 10 and the pressure chamber 14. The drawing passage 35 is connected to a consumption load, for example, a steering mechanism through a flow control valve 17 combined with the throttle mechanism 16.

In FIG. 2, a throttle mechanism 16 and a flow control valve 17 are coaxially inserted into a case bore 18 running perpendicular to the drive shaft 3 at a position shifted from the drive shaft 3. The piston 20 of the flow control valve 17 opens its inner front face 21 and opens the inlet passage 13 (FIG. 1) in a known manner.
To control the passage portion 13A (control through-hole) connected to the control portion. For the sake of clarity, FIG.
It is shifted by 5 ° in the front direction of the figure. In the illustrated start position, the front face 21 is in contact with the throttle sleeve 23 of the throttle mechanism 16 due to the load of the spring 22.
At this time, the passage portion 13A is covered by the control flange 24 of the flow control piston 17. Between the front surface 21 and the throttle mechanism 16, there is a chamber 25 that can be connected to the passage portion 13A.

According to the present invention, the throttle mechanism 16
It consists of the throttle sleeve 23 already described, which is fixedly mounted on the screw body 26 of the case bore 18.
An adjusting shell 27 is guided on the throttle sleeve 23 so as to be shiftable against the force of a spring 28. The adjusting shell 27 has a control edge 30, which controls the variable passage crossing 31 in the throttle sleeve 23, for example in the form of a throttle opening. The slot sleeve 23 has a larger and fixed second passage cross-section 32 on the front face 15 facing the chamber 25 side. Both passage crossings 31 and 32 are connected to a load and lead to an outlet 33. The screw body 26 also has a tubular body 34, which has a through hole 37 in the area of the inlet passage 35 connected to the pump pressure side (pressure chamber 14 in FIG. 1), so that the ring chamber 36 has a ring gap. It is connected to the chamber 25 via 38. The ring gap 38 is formed in the tubular body 34.
Of the adjustment shell 27 and a foot-shaped flange 41 facing outward. The inner curved portion 40 and the flange 41 face each other at the start position of the throttle mechanism 16. The chamber 42 with the spring 22 and outside the flow control valve 17 is closed at the front face 43 of the piston 20. The chamber 42 communicates with the outlet 33 via a straight line 44 indicated by a broken line. FIG. 2 shows the control mechanisms 16 and 17 at a start position when the pump is stopped.

The control mechanism operates as follows. That is, the total flow of the pump is controlled by the suction passage 35 and the tubular body 34
Through the through hole 37 to the ring gap 38. For example, the feed flows through the ring gap 38 until a regulation point at a pump speed of 1000 RPM is reached. This flow corresponds to the passage crossing 31, at which time the piston 20 is slightly away from the front face 15 of the throttle sleeve 23. However, the control flange 24 is still in the passage portion 13A.
(Control case through hole) is not released. In this case, the sending flow passes through the following route. That is, the oil passes through the ring gap 38 and enters the chamber 25, from which simultaneously, at the same time, the variable and fixed second passage crossings 31 and 32.
Through the hollow space of the throttle sleeve 23 to the outlet 33. The control flange 24 of the flow control piston 20 initially closes the passage portion 13A still leading to the suction side.

When the adjustment point is reached, the pressure acting on the front face 21 inside the piston 20 increases the force of the spring 22 and the chamber 4
It becomes higher than the combined force with the force acting on the outer front surface 43 in the inside 2. Similarly, the differential pressure acting on the chamber 25 causes the piston 20 to shift rightward, and a part of the feed flows to the suction side through the passage portion 13A. After the adjustment point, the flow characteristics are kept substantially horizontal in a small rotation speed range.

Since the flow rate increases in proportion to the rotational speed, a pressure which increases in accordance with the rotational speed is generated in front of the ring gap 38, whereby the adjusting shell 27 resists the force of the spring 28 and controls the flow control piston. The adjustment shell 27, which is moved towards 20, starts shielding the first passage crossing 31 at its control edge 30, increasing the shielding in turn and closing it all at the end. The flow characteristics decrease until the variable passage crossing 31 is completely shielded. At this time, all of the flow rate flows through the fixed second passage crossing port 32, and the flow characteristics are kept substantially horizontal by further increasing the rotation speed. The transmission flow rate that further increases with the rotation speed and cannot flow out of the throttle mechanism 16 is increased by the corresponding flow control piston 2.
It is discharged to the pump inlet (passage portion 13A) according to the position of 0.

FIG. 3 shows a modification of the throttle mechanism. In this case, the end of the throttle sleeve 23A on the chamber 25 side is configured as a cone 45, which together with the front edge 46 of the adjustment shell 27A forms a variable passage crossing 31A. Downstream after the first passage crossing 31A, the oil flows through the outlet 47 to the outlet. The second fixed passage crossing 32A in the throttle sleeve 23A is the same as in FIG.

Still another modification will be described with reference to FIG. One example is to omit the second passage crossing 32 and close the throttle sleeve 23 at the front 15.
In this case, the variable passage crossing 31 is configured to be large,
When the spring 28 becomes "blocked", an open residual crossing port is left.

The throttle mechanism 16 of the present invention
Are configured as pre-assembled screw-in cartridges. The screw-in cartridge is easy to replace and can therefore be adapted to various demanding loads by simply changing the cross sectional area or the spring force acting on the adjusting shell 27, 27A.

[0024]

As described above, according to the present invention, the throttle mechanism is provided in the case bore of the flow control piston, the throttle mechanism is fixedly mounted on the screw body, and the throttle mechanism opposes the spring force on the throttle sleeve. Adjustable shell that controls the variable crossing port that can be shifted by shifting, and a tubular body that surrounds the adjustable shell and is integrated with the screw body. There is an effect that an independent feed flow rate can be obtained. According to the second aspect of the present invention, since the fixed crossing port is always held as the residual crossing port, there is an effect that the variable crossing port can be relatively small. According to the third aspect, the variable passage crossing is configured as a throttle bore in the throttle sleeve and cooperates with the control shell and the control edge, so that the load flow rate is relatively small. It has the effect of being suitable. According to claim 4, the free end of the throttle sleeve is configured as a cone, which, together with the front edge of the adjusting shell, forms a variable first passage cross-section, on which the oil flow is introduced. For this reason, since the adjusting shell is further provided with a flow opening, the cross section of the variable ring can be made relatively large, and there is an effect that it is possible to cope with a large load flow rate.
According to a fifth aspect of the present invention, there is provided a threaded tubular body having a plurality of through holes in a region of the pump inlet passage, and a connection from the inlet passage to the ring gap is formed through the through hole. There is an effect that a large flow rate can be obtained in the inside. According to claim 6, the ring gap is:
Since it is formed by the inner curved portion of the tubular body and the outwardly facing foot-shaped flange of the adjusting shell, the inner curved portion and the flange have the effect of being opposed to each other at the start position. According to the seventh aspect, since the throttle mechanism is configured as a screw-in type cartridge, there is an effect that the flow characteristic can be changed only by replacing the cartridge.

[0025]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a vane to which the present invention is applied.

FIG. 2 is an enlarged partial sectional view taken along the line AA of FIG. 1, showing an embodiment of the control mechanism of the present invention at a start position thereof.

FIG. 3 is a partial sectional view of a throttle mechanism showing another embodiment of the present invention.

[0026]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump case 2 Lid 3 Drive shaft 4 Rotor 5 Wing 6 Curve ring 7 Pressure plate 8 Pin 10 Pressure hole 11 Partial ring 12 Suction port 13 Inlet passage 13A Passage part 14 Pressure chamber 15 23 Front 16 Throttle mechanism 17 Flow control valve 18 Case bore 20 17 Piston 21, 43 20 Front 22, 28 Spring 22, 23A Throttle sleeve 24 20 Control flange 25 Chamber 26 Threaded body 27, 27A Adjustment shell 30 27 Control edge 31, 31A Variable passage crossing port 32, 32A Fixed passage crossing opening 33 Outlet 35 Inlet passage 36 Ring chamber 37 Through hole 38 Ring gap 40 Internal curved portion 41 Foot flange 42 Chamber 44 Passage 45 Conical 46 Front of 23A 47 Outlet

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Rainer Meyer DE-7070 Schwabisch Gmundt Gmundelst Lasse 48 (56) References Japanese Utility Model Sho 61-1222978 (JP, U) Japanese Patent Publication Sho 62-9755 (JP) , B2) West German Patent Application Publication 3524413 (DE, A1) (58) Fields investigated (Int. Cl. ⁶ , DB name) F04C 15/04 311

Claims (7)

(57) [Claims] 1. A flow control piston 20 is guided in a case bore 18 provided at right angles to the drive shaft 3. b) The case bore 18 is further provided with a throttle mechanism 16 coupled to an outlet 33 connected to the load side. C) the outer front face 43 of the flow control piston 20 receives the outlet pressure behind the throttle mechanism 16 and simultaneously receives the load of the spring 22; d) the inner front face 21 of the flow control piston 20 applies the pump pressure E) flow control piston 2
0 in the control mechanism of a drainage pump, in particular a vane pump, which forms a connection to the inlet passage 13 on the pressure side of the pump in response to the differential pressure acting on the front faces (21; 43) on both sides. F) a throttle mechanism 16 in the case bore 18 of the flow control piston 20 includes a throttle sleeve 23 fixedly mounted on a screw body 26, an adjustment shell 27 capable of shifting on the throttle sleeve 23 against the force of a spring 28, And a tubular body 34 surrounding the adjusting shell 27 and integral with the screw body 26; g) the adjusting shell 27
Controlling the variable passage crossing 31 to the outlet 33 of the throttle sleeve 23; h) the tubular body 34
7 together with a variable ring gap 38, which constitutes the connection from the pump to the passage cross section 31; and c) the front face 15 of the throttle sleeve 23 carries the pump pressure and is inside the flow control piston 20. A control mechanism for a drainage pump, characterized in that it is restricted at the front face 21 and faces the chamber 42 leading to the inlet passage 13 of the pump. 2. The exhaust passage according to claim 1, wherein the throttle sleeve has a second passage crossing port fixed to an outlet on the front side of the throttle sleeve in addition to the variable passage crossing port. Oil pump control mechanism. 3. The variable passage crossing opening according to claim 1, wherein the throttle passage is configured as a throttle opening in the throttle sleeve, and the throttle bore is controlled by a control edge of the adjusting shell. Control mechanism. 4. The chamber 2 of the throttle sleeve 23A.
The end facing 5 is configured as a cone 45;
The cone 45 forms with the front edge 46 of the adjusting shell 27A a variable first passage cross-section 31A, and an inlet is provided in the adjustment shell 27A after the passage cross-section 31A. The control mechanism according to claim 1, wherein: 5. The tubular body 34 of the screw body 26 forms a ring chamber 36 with the case bore 18 in the area of the pump inlet passage 35, and a plurality of through holes 37 in the tubular body 34. 2. The control mechanism of claim 1 wherein the control mechanism is machined and forms a connection from the ring chamber to the ring gap. 6. The ring gap (38) is formed by an inner curved portion (40) of the tubular body (34) and an outwardly facing foot-shaped flange (41) of the adjusting shell (27). And the inner curved portion 40
The control mechanism for an oil drain pump according to claim 1, wherein the and the flange (41) face each other at a start position. 7. The control mechanism according to claim 1, wherein the throttle mechanism is formed as a screw-in cartridge.