JPH11343984A - Tandem pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized tandem pump consisting of a first and a second circulation control valve in which the distance between the two valves is shortened. SOLUTION: A first flow control valve 15 circulates part of the discharged fluid to the suction side of a first pump unit through a first circulation passage 16 while a second flow control valve 17 circulates part of the fluid to the suction side of a second pump unit through a second circulation passage, wherein the two valves 15 and 17 are positioned separately for the axial length of the first circulation passage 16 or the second. This allows small-sized construction of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tandem pump in which first and second rotatable pump units including first and second rotors are arranged in an integrated pump housing.

[0002]

2. Description of the Related Art As disclosed in Japanese Utility Model Application Laid-Open No. 5-30484 as a hydraulic source for a plurality of hydraulic devices such as a power steering and an active suspension mounted on an automobile, two rotors each rotate within a cam ring. A tandem pump in which a set of pump units is housed in an integrated pump housing is used.

In this apparatus, a first supply passage and a second supply passage branched via an oil reservoir are connected to a common supply port, and a surplus amount of discharge oil guided from the supply passage is sucked. First and second flow control valves for bypassing and recirculating the passage are provided. The first and second supply passages are connected to the suction passage so as to be offset with respect to the center line of the passage, and the bypassed jet flows in this manner. Oil is sucked (supercharged) from the first and second supply passages by the negative pressure generated in the offset portion.

[0004]

In particular, it is desirable that a tandem pump for a vehicle be small in space.
The above-mentioned conventional tandem pump has a configuration in which the first flow control valve and the second flow control valve are separated in the left-right direction by at least the sum of the axial lengths of the respective suction passages. ing.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a tandem pump in which the length of the first recirculation control valve and the second recirculation control valve in the direction of separation is reduced and the size is reduced.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a first pump unit for sucking and discharging a fluid, and a part of a discharge fluid of the first pump unit for a first return path. A first flow control valve for recirculating the fluid to the suction side of the first pump unit, a second pump unit for sucking and discharging the fluid, and a part of the fluid discharged from the second pump unit through the second recirculation path. In a tandem pump in which a second flow control valve for returning to a suction side of a pump unit is housed in an integrated pump housing, the first return path and the second return path are arranged side by side, and the first flow control valve and A second flow control valve is characterized in that it is disposed apart from the first annular flow path or the second annular flow path by an axial length.

[0007] The first annular flow path and the second annular flow path are
It is characterized by being arranged substantially in parallel over substantially the entire length of each.

[0008] Further, the first annular flow path and the second annular flow path,
It is characterized by merging at each end.

Further, one end of the first annular flow path and the second annular flow path is connected to the other start end.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a front housing, and 2 denotes a rear housing. The front housing 1 and the rear housing 2 are integrally connected to form a pump housing. The first side plate 3, the first cam ring 4, and the intermediate side plate 5 are sequentially inserted into this hollow chamber, and the front housing 1 is formed.
The second cam ring 6 and the second side plate 7 are fitted over the rear housing 2. A first pump unit is formed on the first cam ring 4 side including the intermediate side plate 5, and a second pump unit is formed on the second cam ring 6 side.

A rotary shaft 8 is rotatably supported on the front housing 1 and the rear housing 2 around the centers of the first and second cam rings 4 and 6, and the rotary shaft 8 corresponds to the first cam ring 4. The first rotor 9 and the second rotor 10 corresponding to the second cam ring 6 are spline-engaged. The first and second rotors respectively hold a plurality of first vanes and second vanes 10A slidably in the radial direction about the rotation shaft 8 and in the radial direction. , 6 in sliding contact.

The first rotor 4 of the intermediate side plate 5
The first suction port 40 is formed on the end face on the side, and the second suction port 44 is formed on the end face on the second rotor 10 side. The first side plate 3 has a first discharge port 41.
However, the second discharge port 4 is provided on the second side plate 7.
5 are formed.

The supply port 11 is connected to a distribution chamber 12 on the upper part of the front housing 1. A first supply passage 13 and a second supply passage 14 are provided at the bottom of the distribution chamber 12 (see FIGS. 2 and 4). ) Is provided through the bottom. The first and second supply passages 13 and 14 are offset from their center lines in the vicinity of the start ends of the first circulation passage 16 and the second return passage 18 (see FIGS. 2 and 4), respectively.
It is connected to these passages at right angles.

The first and second return passages 16 and 18 are connected to a suction chamber 39, respectively, and merge at the suction chamber 39. The suction chamber 39 surrounds the merging space 37 located above the first side plate 3, the first cam ring 4, the intermediate side plate 5, the second cam ring 6, and the second side plate 7, and the outer periphery of the intermediate side plate 5. And an annular space 38. The suction chamber 39 is connected to a pump chamber (rotor, cam ring, and two adjacent suction chambers) in a suction area of each pump unit via a first suction port 40 and a second suction port 44 that are recessed in the intermediate side plate 5. (A room partitioned by vanes). The annular space 38 does not necessarily need to surround the entire outer periphery of the intermediate side plate 5 and may be any space that connects the merge space 37 with the first and second suction ports 40 and 44. Therefore, grooves can be formed on both sides of the intermediate side plate 5.

A first discharge port 41 formed on the first side plate 3 and a second discharge port 45 formed on the second side plate 7 are connected to the discharge area of each pump unit. The discharge port 41 is connected to a first discharge chamber 42 provided in the front housing 1 from the first discharge chamber 42.
The second discharge port 45 is connected to a second discharge passage 47 from a second discharge chamber 46 provided in the rear housing 2, and is connected to the first pressure chamber 23 of the first flow control valve 15 via a discharge passage 43. Via the second pressure chamber 31 of the second flow control valve 17
It is connected to the.

As shown in FIG. 4, the first flow control valve 15 includes a first union part 22, a first spool 19,
The first union part 22 includes a first outlet 26 connected to, for example, a hydraulic power steering device, and a first outlet 21 that urges the spool 19 toward the first union part 22. A first outflow passage 24 connecting the outlet 26 to the first pressure chamber 23 and a first control orifice 25 for creating a hydraulic driving force for operating the first spool 19 are provided. The first control orifice 25 is configured as a variable orifice whose opening area changes according to the pump rotation speed by the action of the sub-spool 25A.

The first pressure chamber 23 connected to the first discharge chamber 42 by the first discharge passage 43 is formed in the space on one side of the first spool 19 as described above, and the space on the other side is formed in the first spool 19. The first pressure transmission passage 27 forms a spring chamber 20 of the first spring 21 into which the pressure after passing through the first control orifice 25 is introduced.

In the valve receiving hole of the first flow control valve 15,
The starting end of the first annular flow path 16 is connected and extends in the direction of a second flow rate control valve 17 described later.
It is always closed by the first spool 19 biased by the first spring 21.

The second flow control valve 17 also has a second union 32,
The second spool 28 includes a second spring 30 for urging the second spool 28 toward the second union portion 32. The second outlet 33 of the second union 32 is connected to, for example, a hydraulic fan for cooling the engine. Connected to the second outlet 33
Outflow passage 24 connecting the second pressure chamber 31 and
a.

A second pressure chamber 31 connected to a second discharge chamber 46 by a second discharge passage 47 is formed in a space on one side of the second spool 28, and a space on the other side is formed in the middle thereof. The second pressure transmission passage 36 provided with a second control orifice 37 for generating a hydraulic propulsion force for operating the second spool 28 introduces the pressure after passing through the second control orifice 37. Spring chamber 29 of spring 30
Are formed.

In the valve receiving hole of the second flow control valve 17,
The start end of the second return path 18 is connected and extends in the direction of the first flow control valve 15. The connection opening 18 A is normally closed by the second spool 28 urged by the second spring 30. I have.

The second spring chamber 29 is connected to the suction side of the pump unit, for example, the second supply passage 14 by a drain passage 34 provided with an electromagnetic on-off valve 35 in the middle thereof. The opening degree of the electromagnetic on-off valve 35 changes in accordance with, for example, the water temperature of the radiator. When the second spool 28 is operated by a differential pressure across the second control orifice 37, the operation of the electromagnetic on-off valve 35 is performed. 2nd spring chamber 2
The operation of the second spool 28 is controlled in accordance with the temperature of the water by adjusting the pressure in the nozzle 9.

Therefore, the feature of this embodiment is shown in FIGS.
As shown in the figure, the first return path 16 and the second return path 18 are provided side by side, and the first flow control valve 15 and the second flow control valve 17 are connected to the first annular flow path 16 or the second return flow path. The first flow path 16 and the second flow path 18 are separated from each other by the axial length of the annular flow path 18. It is of a length that does not exceed the distance. Also, the first annular channel 1
6 and the second annular flow path 18 are arranged substantially in parallel over substantially the entire length of each. Further, the first annular channel 1
6 and the second annular flow path 18 are merged at their respective ends.

That is, the distance between the first recirculation control valve 15 and the second flow control valve 17 is equal to the first recirculation passage 16 or the second
It is only the axial length of the return path 18. Thus, the length of the housings 1 and 2 in the direction of the rotation axis 8 can be reduced.
Moreover, in this embodiment, the first and second annular flow paths 1
Since the working oil passing through 6, 18 is sucked into each pump through the suction chamber 39, the first and second annular flow paths 1
The lengths of the housings 6 and 18 can be kept to the minimum necessary, which can contribute to shortening of the lengths of the housings 1 and 2 and also improve suction performance by reducing suction resistance of hydraulic oil.

FIG. 5 shows another embodiment of the present invention, in which a first return channel 16 and a second return channel 18 are wrapped up and down, and the end of the second return channel 18 is connected to a first return channel 16. And the two annular flow paths are connected in series. Also in this other embodiment, the first flow control valve 15 and the second flow control valve 17 are arranged so as to be separated by the axial length of the first annular flow path 16 or the second annular flow path 18. It is.

As a result, similar to the previous embodiment,
The length of the housings 1 and 2 in the direction of the rotation axis 8 can be reduced. Also, as in the previous embodiment, the suction chamber 3
9, the length of the first and second recirculation passages 16 and 18 can be kept to a necessary minimum, which contributes to shortening of the length of the housings 1 and 2, and also reduces the suction resistance of the hydraulic oil to improve the suction performance. Can be improved.

In each of these two embodiments, the first
Although the return path 16 and the second return path 18 are juxtaposed in parallel, the purpose of these embodiments is to reduce the size of the housings 1 and 2 by shortening the axial direction of the rotary shaft 8.
It is also possible to adopt a configuration other than the above-mentioned parallel relationship, for example, such that the 6 and the second return path 18 are in a “twisted position” within a design-permissible range.

The operation of the tandem pump according to the present invention having the above-described structure is such that when the first rotor 9 and the second rotor 10 are driven to rotate, the hydraulic oil (fluid) flowing into the suction chamber 39.
Enters the pump chamber through the annular space 38 of the suction chamber 39 and the first and second suction ports 40 and 44 of the intermediate side plate 5,
First and second discharge chambers 4 are provided from first and second discharge ports 41 and 45 of the first side plate 3 and the second side plate 7.
2, 46, first and second discharge passages 43, 47,
First and second pressure chambers 23, 3 of second flow control valves 15, 17
Introduce to 1.

The first of the first and second flow control valves 15, 17
The hydraulic oil introduced into the second pressure chambers 23, 31
The fluid is supplied to each fluid device (for example, a hydraulic power steering device or a hydraulic fan for cooling the engine) through the outflow passages 24 and 24a and the first and second outlets 26 and 33.

At this time, the first and second spools 19, 28
The first and second pressure chambers 23 and 31 have first and second pressure chambers respectively.
The pressures before passing through the control orifices 25 and 37 are also changed by the first and second spring chambers 20 of the first and second spools 19 and 28.
The first and second control orifices 25 and 37 are provided at the end on the 29th side.
After the passage of the first and second control orifices 25 and 37, and operates according to the pressure difference before and after the passage through the first and second control orifices 25 and 37, and the connection openings 16A and 18A of the first and second annular flow paths 16 and 18 are operated.
Adjust the opening of.

When the connection openings 16A and 18A of the first and second annular flow paths 16 and 18 are opened, the first and second pressure chambers 23 and 3 are opened.
A part of the discharge oil in 1 becomes a high-speed jet as a surplus flow, and is discharged to the first and second annular flow paths 16 and 18. At this time, the hydraulic oil is sucked at a negative pressure from the first and second supply passages 13 and 14 by the supercharge effect of the jet, and is sent to the suction chamber 39 together with the hydraulic oil and returned.

The first and second flow control valves 15, 17 are
The configuration as described above, that is, the sub-spool 25A,
It is needless to say that the present invention is not limited to the one having the electromagnetic on-off valve 35 and the like, as long as a part of the discharge fluid of the pump unit is returned to the suction side.

[0033]

As described above, according to the present invention, the first recirculation path and the second annular flow path according to claim 1 are arranged side by side, and the first flow control valve and the second flow control valve are connected. The configuration in which the first annular flow path or the second annular flow path is spaced apart by the axial length, the length in the separation direction between the first flow control valve and the second flow control valve is reduced, and the size is reduced. Was completed. In addition, the first annular flow path and the second annular flow path according to claims 2 to 3 are arranged substantially in parallel over substantially the entire length thereof, and the first annular flow path and the second annular flow path are respectively terminated. And the configuration in which one end of the first annular flow path and the second annular flow path is connected to the other start end of the first annular flow path and the second annular flow path reduces the area occupied by the first annular flow path and the second annular flow path in the pump housing. This contributes to further downsizing of the whole tandem pump in addition to downsizing by the arrangement of the first flow control valve and the second flow control valve.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 is a sectional view of a main part showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front housing 2 Rear housing 3 1st side plate 4 1st cam ring 5 Intermediate side plate 6 2nd cam ring 7 2nd side plate 8 Rotating shaft 9 1st rotor 10 2nd rotor 11 Supply port 12 Distribution chamber 13 1st supply Passageway 14 Second supply passage 15 First flow control valve 16 First annular flow path 17 Second flow control valve 18 Second annular flow path 39 Suction chamber 40 First suction port 41 First discharge port 43 First discharge passage 44 Second suction Port 45 Second discharge port 47 Second discharge passage

Claims (4)

[Claims] 1. A first pump unit for sucking and discharging a fluid, and a first flow control valve for recirculating a part of the discharge fluid of the first pump unit to a suction side of the first pump unit through a first return line. And a second pump unit for sucking and discharging the fluid, and a second flow control valve for returning a part of the discharge fluid of the second pump unit to the suction side of the second pump unit through a second return path. In a tandem pump housed in a pump housing, the first return path and the second return path are arranged side by side, and the first flow control valve and the second flow control valve are connected to the first annular flow path or the second return flow path. A tandem pump characterized by being arranged so as to be spaced apart by an axial length of an annular flow path. 2. The tandem pump according to claim 1, wherein the first annular flow path and the second annular flow path are arranged substantially in parallel over substantially the entire length of each. 3. The tandem pump according to claim 1, wherein the first annular flow path and the second annular flow path are joined at their respective ends. 4. The terminal according to claim 1, wherein one end of the first annular channel and the second annular channel is connected to the other end.
Or the tandem pump according to claim 2.