JPH07238883A - Plunger pump - Google Patents

Abstract

PURPOSE:To discharge a large volume of hydraulic fluid by a small plunger pump without increasing number of the plunger. CONSTITUTION:A plunger pump 1 is formed with a front side radial plunger pump 2 and a rear side radial plunger pump 3. The front and rear side radial plunger pumps 2, 3 are respectively formed with housings 4, 5 having front and rear side bores 21, 31 and pressure portions 6, 7 having check valves 8, 9. A passage 26A for communicating with the front side pressure chamber 6a and the rear side bore 31 is formed in the rear side housing 5. A check valve 8A for allowing only current of hydraulic fluid from the rear side bore 31 to the front side pressure chamber 6a is mounted in this passage 26A. Thereby, a large volume of the hydraulic fluid can be discharged by the front side radial plunger pump 2 without increasing the number of the plunger 40 and also the plunger pump 1 can be minimized and lightened entirely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plunger pump of a suction limiting type used as a hydraulic power source for a hydraulic system for automobiles such as a power steering device and a suspension device for automobiles.

[0002]

2. Description of the Related Art For example, a tandem pump as shown in FIGS. 11 and 12 is used as a hydraulic power source for a power steering device for an automobile. This tandem pump has a radial plunger pump 101 on the right end side and a vane pump 102 on the left end side in FIG. In the radial plunger pump 101, plungers 114 are housed in a plurality of plunger housing holes 113 formed in the housing 110 so as to be able to advance and retract in the radial direction, and each plunger 114 rotates in the housing 110 with an eccentric cam 119. When it is pushed by and repeatedly moved forward and backward, the hydraulic oil in the suction chamber 112 is sucked into the plunger through a plurality of suction holes formed in the peripheral wall of the plunger 114, and then sent to the discharge port 117 via the check valve 115. It is like this. Further, the vane pump 102 on the other end side is
A plurality of vanes are attached to a rotor 120 that is driven and rotated so as to be retractable and retractable in a substantially radial direction. When the rotor 120 rotates in the cam ring 121, each vane is moved to the cam ring 12
Sliding contact with the inner surface of 1 and repeating the projecting and retracting operation, thereby increasing or decreasing the volume between adjacent vanes to perform a pumping action. The oil discharged from each pump is discharged independently.

Incidentally, as a technique similar to this, the actual exploitation 6
No. 0-28575.

[0004]

However, in the above-mentioned conventional tandem pump, since the discharge of each pump is independent, when a large amount of discharge oil is needed for a large capacity actuator, the input side When increasing the discharge capacity of the plunger pump, it is necessary to increase the number of cylinders of the plunger 114, and when increasing the discharge capacity of the vane pump, it is necessary to increase the diameter of the cam ring 121 and the like. There was a problem that the pump became large.

Therefore, the present invention provides a small-sized plunger pump having front and rear plunger pumps capable of discharging large-capacity and small-capacity hydraulic oil, respectively, without increasing the number of plungers. Is.

[0006]

[MEANS FOR SOLVING THE PROBLEMS] A suction chamber, a plurality of plunger accommodating holes communicating with the suction chamber, a plunger reciprocatingly housed in each of the plurality of plunger accommodating holes, and the plurality of plunger accommodating holes. A pressure chamber for discharging the hydraulic oil therein, a passage communicating with each of the plurality of plunger accommodating holes and the pressure chamber, and provided in the passage to allow the flow of the hydraulic oil from the plunger accommodating hole to the pressure chamber. And a check valve for controlling the reciprocating motion of the plunger to pump the hydraulic oil sucked from the suction chamber into the plunger storage hole into the pressure chamber from the plunger storage hole through the passage and the check valve into a single pump unit. At least two of the plunger pumps are coaxially arranged, and at least one of the plunger pumps is connected to the above-mentioned communication. All or part of the are communicated with the pressure chamber of the other plunger pump.

[0007]

The hydraulic oil on the side of the plunger housing hole of at least one plunger pump is pressure-fed to the pressure chambers of the other plunger pumps and merges with each other, and a large amount of hydraulic oil is discharged from the other plunger pumps. As a result, a larger volume of hydraulic oil is discharged than the other plunger pumps without increasing the number of plungers of the other plunger pumps. Further, since it is not necessary to increase the size of other plunger pumps, it is possible to reduce the size and weight of the entire plunger pump.

[0008]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 and 2, reference numeral 1 denotes a tandem plunger pump of a suction restriction type, which has radial plunger pumps 2 and 3 for large and small capacity actuators having substantially the same structure on the front and rear sides of an automobile. It is used as a hydraulic power source for power steering devices and suspension devices for automobiles. The radial plunger pumps 2 and 3 for the front and rear large and small capacity actuators are made of aluminum alloy as a plunger housing body forming front and rear plunger housing holes, and have substantially cylindrical housings 4 and 5.
And the pressure portions 6 and 7 made of aluminum alloy and having substantially cylindrical shape and having check valves (check valves) 8 and 9, respectively, are sequentially stacked and fastened to each other with bolts 10. ing. The fastening method may be a thread groove.

A single drive shaft 13 having a pair of front and rear eccentric cams 11 and 12 is housed in the front and rear housings 4 and 5 in the axial direction, and the front eccentric cam 11 is driven by the drive shaft 13. The rear eccentric cam 12 is attached to the drive shaft 13 via a key 14. The drive shaft 13 is a ball bearing 15 as a bearing press-fitted and fixed to the drive shaft 13 and needle bearings 16a, 16b, 16c as bearings press-fitted and fixed in the front and rear housings 4, 5. It is rotatably supported by. On the outer peripheral surface side of the eccentric cams 11 and 12 of the drive shaft 13, the outer ring thick solid type needle bearings 17a and 17b are fitted, while the eccentric cams 11 and 12 of the drive shaft 13 are A pair of thrust washers 18a, 18 for restricting axial movement of the needle bearings 17a, 17b are provided on the front and rear surfaces.
b and 19a, 19b are provided.

Each space between the ball bearing 15 and the needle bearing 16a and between the needle bearing 16b and the needle bearing 16c in the front and rear housings 4 and 5 allows the eccentric cams 11 and 12 to rotate therein. At the same time, front and rear suction chambers 20 and 30 are formed respectively. Front and rear housings 4, 5
A plurality of bores (plunger housing holes) 21 and 31 for housing the bottomed cylindrical plungers 40 and 50 in the radial direction are provided on the outer peripheral side of the suction chambers 20 and 30 in a radial direction at several locations. ing. Each of the bores 21 and 31 is made of an iron casting and has a cylindrical shape near the suction chamber side (inside) of each of the circular holes 4a and 5a radially communicating with the front and rear housings 4 and 5 in the radial direction. Are formed by press-fitting the respective sleeves 22 and 32. Further, in each of the bores 21 and 31, the needle bearings 17 fitted to the pair of front and rear eccentric cams 11 and 12 of the drive shaft 13 are fitted.
The bottomed cylindrical plungers 40 and 50 are slidably housed so that the bottom surfaces of a and 17b come into contact with each other. A few suction holes 4 are provided on the peripheral wall of each plunger 40, 50.
0a and 50a are formed.

On the open end side (outside) of each of the round holes 4a, 5a formed in the front and rear housings 4, 5, the threaded portion 4 is provided.
b and 5b are formed. In order to form the pump chambers 25 and 35, the plug-like cylindrical plugs 24 and 34 are screwed into the screw portions 4b and 5b via the rubber O-rings 23 and 33 as seal members. Has become. Each retainer 41 fitted to the lid side of each plug 24, 34,
Between the 51 and the plungers 40, 50, the springs 42, 52 for interposing the plungers 40, 50 constantly in the direction of the eccentric cams 11, 12 are interposed.

In the front and rear housings 4 and 5, a discharge passage 26 is provided so that hydraulic oil flows from the pump chambers 25 and 35 to the check valves 8 and 9 of the front and rear pressure portions 6 and 7, respectively. , 3
6 are formed, and the discharge passages 26, 36 and the check valves 8, 9 are provided in the same number as the bores 21, 31. The hydraulic fluid discharged by the pump action is made of aluminum alloy and is cast into the pressure chambers 6a, 7a on the front and rear sides, which have annular cavities on the inner side.
The check valves 8 and 9 are press-fitted and fixed into the mounting holes 6b and 7b formed in the valve 7. The front and rear pressure portions 6 and 7 are sealed in the front and rear housings 4 and 5 via a pair of rubber O-rings 27a, 27b, 37a and 37b as seal members, Discharge passages 26, 3 from the pump chambers 25, 35
The check valve 6 and the check valves 8 and 9 are hermetically sealed via rubber O-rings 28 and 38 as seal members.

In this tandem plunger pump,
If the pump capacity of the radial plunger pump 2 on the front side for a large capacity actuator is F and the required capacity (discharging amount) required for the radial plunger pump 2 is L, the pump capacity F becomes smaller than the required capacity L. Is set. Further, when the pump capacity of the rear radial plunger pump 3 is R and the required capacity (discharging amount) required of the radial plunger pump 3 is S, the pump capacity R is set to be larger than the required capacity S. I am doing it. At this time, the sum of the pump capacity F of the front side radial plunger pump 2 and the pump capacity R of the rear side radial plunger pump 3 is the required capacity L of the front side radial plunger pump 2 and the demand of the rear side radial plunger pump 3. It is set to be the sum of the capacities S.

Furthermore, in order to supplement the shortage capacity (LF) of the front radial plunger pump 2 with the surplus capacity (RS) of the rear radial plunger pump 3, an excess capacity (RS) is provided. The passage 26A for guiding the discharge amount of the hydraulic oil for several plungers of the rear radial plunger pump 3 corresponding to the inside of the pressure chamber 6a of the pressure portion 6 of the front radial plunger pump 2 to the plunger of the rear housing 5 The bore 31 as a storage hole and the pressure chamber 6a of the front pressure portion 6
It is formed so as to communicate with and. As shown in FIG. 1, the mounting hole 6d formed in the inner wall of the pressure chamber 6a of the pressure portion 6 on the front side in the passage 26A is located in front of the bore 31 side (pump chamber 35) of the rear housing 5. A check valve 8A that allows only the flow of hydraulic oil to the pressure chamber 6a of the pressure portion 6 is press-fitted and fixed. The pressure chamber 6a of the pressure portion 6 is pushed from the pump chamber 25 of the front housing 5 by being press-fitted and fixed in the tip surface of the check valve 8a and the mounting hole 6b of the front pressure portion 6.
Is in contact with the tip surface of the check 8 which allows only the flow of hydraulic oil to the.

As shown in FIGS. 5 (a) and 5 (b), each of the check valves 8 (8A has the same structure as 8) and 9 has a cylindrical shape in which a plurality of holes 81a and 91a are formed substantially in the center of the peripheral wall portion. Housing main bodies 81, 91 and seat valves 82, 92 press-fitted or screwed into the bases of the housing main bodies 81, 91.
And the valves 84 and 94 interposed in the housing bodies 81 and 91 by being biased toward the seat valves 82 and 92 by the elastic force of the springs 83 and 93.

The suction chamber 20 of the front housing 4 and the suction chamber 30 of the rear housing 5 communicate with each other through a suction passage 29 formed in the front housing 4. Further, a suction port 5c for introducing hydraulic oil from the outside is formed in the rear housing 5. A suction pipe 53 is connected to an upper portion of the suction port 5c through a rubber O-ring 54 as a sealing member, and a lower portion of the suction port 5c is formed in an annular shape substantially at the center of the inner peripheral surface of the rear housing 5. Communicating with the annular passage 39. The annular passage 39 communicates with the suction chamber 20 of the front housing 4 and the suction chamber 30 of the rear housing 5 via the suction passage 29.
Furthermore, the annular press-fitting chambers 6 of the pressure parts 6 and 7 on the front and rear sides, respectively.
Discharge ports 6e and 7e for sending hydraulic oil to the actuator side are formed in a and 7a.

The left end side of the drive shaft 13 in FIG. 1 is exposed to the outside of the front housing 4 and is kept oiltight by an oil seal 45. That is, the oil seal 45 is press-fitted and fixed to the collar 46, and a rubber O-ring 47 as a seal member provided on the outer periphery of the collar 46.
Due to this, oil tightness with the front housing 4 is maintained. The collar 46 is held on the front housing 4 by a snap ring 48. Also, drive shaft 1
The right end side of 3 is housed in the rear housing 5,
Oil tightness is maintained through a cover 55 that covers the outer surface of the rear housing 5 and the outer surface of the rear pressure portion 7 and a rubber O-ring 56 as a seal member. Further, the front pressure portion 6 and the rear housing 5 are sealed by a rubber O-ring 57 as a sealing member.

According to the tandem plunger pump 1 having the structure of the above embodiment, an external drive source (for example, vehicle engine).
When the drive shaft 13 rotates by the pair of front and rear eccentric cams 11 and 12 provided on the drive shaft 13, the plungers 40 and 50 move up and down in the radial direction along the bores 21 and 31, respectively. At this time, each plunger 4
The suction holes 40a, 50a of 0, 50 are arranged in the suction chambers 20, 3 respectively.
The hydraulic oil flows into each of the plungers 40 and 50 while the hole is opened to zero. At this time, the pump chambers 25 and 35 are under suction pressure, and the check valves 8 and 9 are closed. When the plungers 40, 50 move upward due to the pressing of the eccentric cams 11, 12 by the rotation of the drive shaft 13,
Intake holes 40a, 5 in the peripheral wall of each plunger 40, 50
0a is closed by the bores 21 and 31 and moves to the compression process, and the hydraulic oil in the plungers 40 and 50 pushes up the check valves 8 and 9 to raise the annular pressure chambers 6a and 7a of the pressure portions 6 and 7, respectively. Is discharged inside. The pumping action is performed by repeating this process.

At this time, from the discharge port 6e of the front radial plunger pump 2, a large capacity (R-S) is added, which is the capacity of the rear radial plunger pump 3 to merge via the passage 26A and the check valve 8A. Is discharged, and from the discharge port 7e of the radial plunger pump 3 on the rear side, a small amount of hydraulic oil minus the above capacity (RS) is discharged. That is, as shown in FIGS. 6A and 6B, the radial plunger pump 101 and the vane pump 102 of the tandem pump of the conventional example have the same flow rate characteristics, and the control discharge amount H of the hydraulic oil is, for example, 7 L / min. In comparison with the above case, in this embodiment, if it is set so that the hydraulic oil of 3 L / min flows from the rear radial plunger pump 3 into the front radial plunger pump 2, for example, the tandem plunger pump 1 Discharge amount L of the radial plunger pump 2 on the front side of
Is 10 L / min, and the control discharge amount S of the radial plunger pump 3 on the rear side is 4 L / min.

As described above, when the tandem plunger pump 1 is used as the hydraulic power source of the hydraulic system for an automobile which requires a large-capacity actuator and a small-capacity actuator, the number of plungers 40 of the front side pressure section 6 is Even if the number of the plungers 50 of the rear pressure unit 7 is the same, for example, the front radial plunger pump 2 can be used for a large capacity actuator. In this case,
A large amount of hydraulic oil can be discharged without increasing the size of the plunger radial pump 2 on the front side. This allows
The tandem plunger pump 1 can be reduced in size and weight. Further, even if the diameters of the plungers 40 and 50 are small, a large amount of hydraulic oil can be secured, and when the diameters of the plungers 40 and 50 are small,
Wear of the bottom surfaces of the plungers 40 and 50 and the cam surfaces of the eccentric cams 11 and 12 can be prevented. Further, the supply side plunger 5 for discharging from the rear side pump chamber 35 to the front side pressure chamber 6a.
The ratio of the discharge amounts of the front and rear pumps 2 and 3 can be easily changed and set only by changing the number of cylinders of 0 (the number of passages 26A and the number of check valves 8A).

The tandem plunger pump 1 of this embodiment
Then, as shown in FIGS. 7 and 8, the front and rear pressure portions 6,
Since ribs 6f and 7f are integrally formed in the vicinity of the mounting holes 6b and 7b of the pressure chambers 6a and 7a of the valve 7 so as to be parallel to the check valves 8 and 9, the bases of the check valves 8 and 9 described above are formed. The rigidity of the press-fitted surfaces of the pressure parts 6 and 7 when the press-fitted and fixed to the mounting holes 6b and 7b of the pressure parts 6 and 7 is increased. That is, like the pressure portions 6 and 7 shown in FIGS. 9 and 10, ribs 6f and 7f are provided near the mounting holes 6b and 7b of the pressure chambers 6a and 7a.
If the check valves 8 and 9 are not provided, when press-fitting the check valves 8 and 9 into the mounting holes 6b and 7b of the front and rear pressure portions 6 and 7, as shown by the dotted line in FIG. Deformation may occur on the mounting holes 6b, 7b side of each pressure portion 6, 7 and the sealing performance between the front and rear housings 4, 5 and the front and rear pressure portions 6, 7 may deteriorate. However, in the tandem plunger pump 1 of this embodiment, ribs are formed in the vicinity of the mounting holes 6b and 7b of the pressure chambers 6a and 7a of the front and rear pressure portions 6 and 7 so as to be parallel to the check valves 8 and 9, respectively. Since 6f and 7f are integrally formed, the mounting holes 6b and 7 of the pressure portions 6 and 7 are formed.
The rigidity on the side b is increased, and when the check valves 8 and 9 are press-fitted and fixed, it is possible to reliably prevent the deformation of the pressure holes 6 and 7 on the mounting holes 6b and 7b side. As a result, the sealability between the front and rear housings 4 and 5 and the front and rear pressure portions 6 and 7 can be reliably ensured.

According to the present embodiment, the housing, the pressure portion and the like are made of aluminum alloy, but they may be made of other members such as cast iron. Further, the invention is not limited to the tandem pump, but may be a plunger pump in which three or more pumps are combined. Also in this case, any number of plunger storage holes of at least one pump and the pressure chambers of other plunger pumps may be communicated with each other.

[0024]

As described above, according to the present invention, the suction chamber, the plurality of plunger storage holes communicating with the suction chamber, and the plungers reciprocatingly housed in the plurality of plunger storage holes, respectively. A pressure chamber that discharges the hydraulic oil in the plurality of plunger storage holes, a passage that communicates each of the plurality of plunger storage holes with the pressure chamber, and a passage that is provided in the passage and that extends from the plunger storage hole to the pressure chamber. And a check valve that allows the flow of hydraulic oil, and the reciprocating motion of the plunger causes the hydraulic oil sucked from the suction chamber into the plunger storage hole to be pumped from the plunger storage hole to the pressure chamber through the passage and the check valve. Plunger pump is one pump unit, at least two plunger pumps are arranged coaxially, and at least one of these plunger pumps Since all or part of the passageway of Yaponpu made to communicate with the pressure chamber of the other plunger pump,
The hydraulic oil on the side of the plunger housing hole of one plunger pump can be jointly discharged to the pressure chamber of the other plunger pump through the passage and the check valve. As a result, a large volume of hydraulic oil can be discharged from the other plunger pump without increasing the number of plungers of the other plunger pump, and the other plunger pump can be downsized. As a result, it is possible to further reduce the size and weight of the entire plunger pump.

[Brief description of drawings]

FIG. 1 is a sectional view of a tandem plunger pump showing an embodiment of the present invention.

FIG. 2 is a front view of the tandem plunger pump of the above embodiment.

FIG. 3 is an enlarged cross-sectional view of a front plunger housing portion of the tandem plunger pump of the above embodiment.

FIG. 4 is an enlarged sectional view of a rear side plunger storage portion of the tandem plunger pump of the above embodiment.

5A is a sectional view of a check valve used in the tandem plunger pump of the above embodiment, and FIG. 5B is a sectional view taken along line XX of FIG. 5A.

FIG. 6A is a diagram showing a flow rate characteristic of a tandem plunger pump in the case where the front and rear pump units have the same flow rate characteristic, and FIG. 6B is the above embodiment comparing with FIG. 6A. The figure which shows the flow rate characteristic of the tandem plunger pump of FIG.

FIG. 7 is a sectional view of the vicinity of a pressure chamber used in the tandem plunger pump of the above embodiment.

FIG. 8 is a sectional view taken along line ZZ in FIG.

9 is a cross-sectional view of the vicinity of a pressure chamber used in the tandem plunger pump showing the comparative example of FIG. 7.

10 is a cross-sectional view taken along the line WW of FIG.

FIG. 11 is a sectional view of a conventional tandem plunger pump.

12 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 ... Tandem plunger pump 2, 3 ... Plunger pump 6, 7 ... Pressure part 8, 9, 8A ... Check valve 20, 30 ... Suction chamber 21, 31 ... Plunger housing hole 26, 29 ... Passage 40, 50 ... Plunger

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F04B 49/00 341

Claims (1)

[Claims] 1. A suction chamber, a plurality of plunger accommodating holes communicating with the suction chamber, a plunger that is housed in each of the plurality of plunger accommodating holes and is capable of reciprocating motion, and hydraulic oil in the plurality of plunger accommodating holes. A pressure chamber that discharges the pressure chamber, a passage that communicates each of the plurality of plunger accommodating holes with the pressure chamber, and a check valve that is provided in the passage and that allows the flow of hydraulic oil from the plunger accommodating hole to the pressure chamber. Equipped with
The plunger pump that pumps the hydraulic oil sucked from the suction chamber into the plunger storage hole into the pressure chamber through the passage and the check valve by the reciprocating motion of the plunger is used as one pump unit. At least two of the plunger pumps are arranged above, and all or part of the passage of at least one of the plunger pumps communicates with a pressure chamber of another plunger pump.