JPH07238884A - Plunger pump - Google Patents

Abstract

PURPOSE:To reduce exchange the number of parts due to defective machining, etc., to the minimum and reduce the cost by forming a plunger pump by mutually connecting respective pump units. CONSTITUTION:A plunger pump 1 is formed with a front side pump unit 2 and a rear side pump unit 3. Respective housings of the front and rear side pump units 2, 3 are formed y front and rear side plunger storing units 4, 5 and pressure chambers 6, 7 having check valves 8, 9 for relatively dividing. Thereby, the plunger pump 1 can easily be assembled by piling up the front side plunger storing unit 4, the front side pressure chamber 6 having the check valve 8, the rear side plunger storing unit 5, the rear side pressure chamber 7 having the check valve and a cover 55 sequentially and securely fixing them by bolts 10.

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 plunger pump is used as a hydraulic power source of a power steering device for an automobile.
This plunger pump has 2
The base plunger pump is formed, and the hydraulic oil is discharged from each independent discharge port. This similar structure is disclosed, for example, in Japanese Patent Laid-Open No. 56-98581.

[0003]

However, in the above-mentioned conventional plunger pump, two plunger pumps are formed in one housing, and the discharge ports corresponding to each row are provided, so that the hydraulic pressures of two systems are provided. Since the system supplies hydraulic oil to the system, if processing defects occur in either the front or rear plunger pump during the manufacturing stage, even if the other plunger pump is normal, ， It is necessary to replace the entire pump housing that houses the rear plunger, and the other normal plunger pump must also be replaced, and it is necessary to take performance from the beginning, reducing production efficiency. At the same time, there is a problem that it causes a cost increase.

Therefore, the present invention provides a plunger pump which can improve productivity, minimize replacement parts, and reduce costs.

[0005]

[MEANS FOR SOLVING THE PROBLEMS] A suction chamber formed in a housing, and a plunger housing hole communicating with the suction chamber,
A plunger accommodated in the plunger accommodating hole and a pressure chamber communicating with the plunger accommodating hole are provided, and the reciprocating motion of the plunger causes the working oil sucked into the plunger accommodating hole from the suction chamber to flow from the plunger accommodating hole into the pressure chamber. A plurality of pump units are arranged coaxially, and the pump units are fastened to each other.

[0006]

Since the plurality of pump units are coaxially arranged and the respective pump units are fastened to each other to form the plunger pump, the plunger pump can be easily assembled and disassembled. As a result, productivity is improved, and replacement parts due to processing defects and the like are minimized, and costs are reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1 and FIG. 2, reference numeral 1 is a suction-limited tandem plunger pump, which has coaxial radial plunger pumps (pump units) 2 and 3 on the front and rear sides, and a power steering device for an automobile. It is used as a hydraulic power source for suspension devices and the like. The front and rear housings of the radial plunger pumps 2 and 3 are made of aluminum alloys, which are made of aluminum alloy, and have substantially cylindrical cylindrical housings 4 and 5 and check valves (check valves).
The front and rear pressure parts 6 and 7, which are made of an aluminum alloy and have a substantially cylindrical shape, can be divided from each other and fastened and fixed by bolts 10. The fastening method is not limited to the bolt, and may be a screw or the like.

A single drive shaft 13 having a pair of front and rear eccentric cams 11 and 12 is housed in the front and rear plunger storage portions 4 and 5, respectively. The eccentric cam 12 on the rear side is formed integrally with the drive shaft 13 via a key 14. The drive shaft 13 is a ball bearing 15 as a bearing that is press-fitted and fixed to the drive shaft 13, and needle bearings 16a and 16b as bearings that are press-fitted and fixed in the front and rear plunger storage portions 4 and 5. , 16c are rotatably supported. In addition, the drive shaft 13
While the outer ring side of the eccentric cams 11 and 12 is fitted with thick outer ring solid type needle bearings 17a and 17b, the eccentric cams 11 and 12 of the drive shaft 13 are connected to the front and rear sides thereof, respectively. A pair of thrust washers 18a for restricting axial movement of the needle bearings 17a, 17b,
18b and 19a, 19b are provided.

Between the ball bearing 15 and the needle bearing 16a in the front and rear plunger housings 4 and 5, and between the needle bearing 16b and the needle bearing 16
Each space between c forms the front and rear suction chambers 20 and 30 while allowing the eccentric cams 11 and 12 to rotate therein. On the outer peripheral side of the suction chambers 20, 30 in the front and rear plunger storage portions 4, 5, there are bores (plunger storage holes) for storing the bottomed cylindrical plungers 40, 50 in the radial direction. ) 21 and 31 are provided in several radial positions. Each of these bores 21, 3
Reference numeral 1 is a cylindrical sleeve made of iron casting near the suction chamber side (inner side) of several circular holes 4a, 5a that radially communicate with the radial outer sides of the front and rear plunger storage portions 4, 5. It is formed by press-fitting 22, 32.
Then, in each of the bores 21 and 31, each of the bottomed cylindrical shapes is contacted so that the bottom surface comes into contact with the needle bearings 17a and 17b fitted to the pair of front and rear eccentric cams 11 and 12 of the drive shaft 13. Plungers 40 and 50 are slidably accommodated. Several suction holes 40a and 50a are formed in the peripheral wall of each plunger 40 and 50.

Threaded portions 4b and 5b are formed on the open ends (outsides) of the round holes 4a and 5a formed in the front and rear plunger housing portions 4 and 5, respectively. These screw parts 4b and 5b
The rubber O-rings 23 and 33 as seal members are
The cylindrical plugs 24 and 34 with a lid are screwed together to form the pump chambers 25 and 35, respectively. Each retainer 4 fitted to the lid side of each plug 24, 34
Between each of the plungers 1, 51 and each of the plungers 40, 50, there are interposed each of the springs 42, 52 for constantly urging the plungers 40, 50 in the direction of the eccentric cams 11, 12.

The front and rear plunger storages 4 and 5 are
Discharge passages 26 and 36 are formed so that hydraulic oil flows from the pump chambers 25 and 35 to the check valves 8 and 9 which are press-fitted and fixed to the front and rear pressure portions 6 and 7, respectively. The discharge passages 26 and 36 and the check valves 8 and 9 are provided in the pump chamber 2
The same number as the number of cylinders of 5,35 is provided. The hydraulic fluid discharged by the pumping action is made of aluminum alloy and has the above-mentioned front and rear pressure chambers 6a each having an annular cavity inside by casting.
Each cylinder is designed to flow into the cylinder 7a through the check valves 8 and 9 press-fitted and fixed in the mounting holes 6b and 7b formed in the pressure portions 6 and 7, respectively. Further, the front and rear pressure portions 6 and 7 are provided in the front and rear plunger storage portions 4 and 5, respectively, as a pair of rubber O-rings 27a and 27 as seal members.
b, 37a, 37b, and the discharge passages 26, 36 and the check valves 8, 9 are closed by rubber O-rings 28, 38 as seal members.

As shown in FIGS. 5 and 6, each of the check valves 8 and 9 has a plurality of holes 81a and 91a formed in the peripheral wall portion and cylindrical stopper portions 81b and 91b integrally formed at the tip end portion thereof. Cylindrical main bodies 81, 91 and each main body 8
The seat valves 82 and 92 are press-fitted or screwed into the base a of the seats 1, 91, and the seat valves 82 and 92 are urged by the elastic force of the springs 83 and 93 to be interposed in the main bodies 81 and 91. It is composed of valves 84 and 94. The check valves 8 and 9 press-fit and fix the base portion a of the main bodies 81 and 91 into the mounting holes 6b and 7b formed on the discharge passages 26 and 36 side of the pressure portions 6 and 7, respectively. The stoppers 81b and 91b are provided with holes 6c, which are formed in the inner walls of the annular pressure chambers 6a and 7a of the pressure units 6 and 7, respectively.
It is attached so that it can be received by 7c. Ribs r are formed in the pressure chambers 6a, 7a of the pressure portions 6, 7 to prevent the pressure chambers 6a, 7a from being deformed by the press-fitting load when the check valves 8, 9 are press-fitted.

The suction chamber 20 of the plunger accommodating portion 4 constituting the front plunger pump 2 and the suction chamber 30 of the plunger accommodating portion 5 constituting the rear plunger pump 3 are formed in the front plunger accommodating portion 4. The suction passages 29 communicate with each other. Further, a suction port 5c for introducing hydraulic oil from the outside is formed in the rear plunger storage portion 5. A suction pipe 53 is connected to an upper portion of the suction port 5c via a rubber O-ring 54 as a seal member, and a lower portion of the suction pipe 53 is provided at a rear side of the plunger storage portion 5c.
It communicates with an annular passage 39 formed in an annular shape in the inner peripheral portion of the. The annular passage 39 communicates with the suction chamber 20 of the front plunger storage portion 4 and the suction chamber 30 of the rear plunger storage portion 5 via the suction passage 29. further,
The annular pressure chambers 6a, 7a of the front and rear pressure portions 6, 7 are provided with respective discharge ports 6e, 7e for sending the hydraulic oil to the outside.

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

In the tandem plunger pump 1 having the above-described embodiment structure, radial plunger pumps 2 and 3 as pump units having substantially the same structure are arranged on the front side and the rear side coaxially with one drive shaft 13. That is, the plunger accommodating portion 4 constituting the front housing and the front row pressure portion 6 having the check valve 8 are stacked, and the plunger accommodating portion 5 constituting the rear housing and the rear accommodating portion having the check valve are stacked thereon. The pressure unit 7 and the pressure unit 7 are stacked and fastened together by bolts 10 or the like to be assembled.

When the drive shaft 13 is rotated by an external drive source (eg, vehicle engine), the drive shaft 13 is rotated.
The plungers 40 and 50 move up and down in the radial direction along the bores 21 and 31, respectively, by a pair of front and rear eccentric cams 11 and 12. At this time, the suction holes 40a and 50a of the plungers 40 and 50 are respectively attached to the suction chambers 2
While opening the holes 0, 30, each plunger 40, 50
Hydraulic fluid flows into the inside. At this time, each pump chamber 25, 3
The inside of 5 has a suction pressure, and the check valves 8 and 9 are closed. Each eccentric cam 11, 1 by rotation of the drive shaft 13
When the plungers 40, 50 are moved upward by the pressing of 2, the suction holes 40 in the peripheral wall portion of the plungers 40, 50.
a, 50a are closed by the respective bores 21, 31 and proceed to the compression process, and the hydraulic oil in the respective plungers 40, 50 pushes up the respective check valves 8, 9 to raise the annular pressure chambers 6a of the respective pressure portions 6, 7. It is discharged into 7a. The pumping action is performed by repeating this process.

As described above, in the tandem plunger pump 1 of the suction limiting type, the front and rear radial plunger pumps 2 and 3 respectively form independent front and rear housings, and the front and rear plunger storage portions 3 and 3, respectively. 4 and front and rear pressure parts 6 and 7 having the respective check valves 8 and 9 are configured to be separable, and the front side plunger storage part 4 and the pressure part 6 with the front side check valve 8 are provided. Since the plunger storage portion 5 on the rear side, the pressure portion 7 with the check valve 9 on the rear side, and the cover 55 are stacked in this order and fastened to each other by bolts and the like to assemble, defective machining and malfunction in the manufacturing process are performed. ， In case of characteristic failure,
For example, if the plunger 40 of the front radial plunger pump 2 is malfunctioning, the front plunger storage unit 4
Is replaced with a new one, or when a porosity or the like from the pressure chamber 7a of the rear pressure part 7 having the check 9 is generated, only this rear pressure part 7 is replaced with a new one. . That is, in the present embodiment, the tandem plunger pump 1 is provided with two pump units 2, which include front and rear plunger storage portions 4 and 5 and front and rear pressure portions 6 and 7.
It is possible to replace only the part of the block that needs to be replaced by configuring the block with a total of four blocks, and each block as an independent assembly. This makes it possible to minimize the number of replacement parts and reduce the cost, as compared with the case where the entire pump housing is replaced as in the conventional case. In this embodiment, the front and rear pump units have the plunger housing portion and the pressure portion as separate bodies, but the plunger housing portion and the pressure portion may be formed in one housing. Alternatively, a plurality of pump units may be coaxially arranged and fastened together.

Further, in this embodiment, the check valves 8 and 9 have a base portion a having mounting holes 6b for the pressure portions 6 and 7,
7b is press-fitted and fixed, and stopper portions 81b, 9
Since the holes 1c and 7c of the pressure portions 6 and 7 receive 1b, the check valves 6 and 7 and the check valves 8 and 9 have different thermal expansion due to a difference in material between the check portions 6 and 7 at high temperature. , 7 does not come off. Furthermore, each pressure chamber 6a,
Even if an excessive surge pressure is generated in 7a, there is no risk of the check valves 8 and 9 coming off, and a stable pumping action can always be ensured. Furthermore, the check valves 8 and 9 to the mounting holes 6b and 7b of the pressure units 6 and 7, respectively.
The press-fitting margin of is small, and it becomes unnecessary to strictly control the dimensional accuracy of the mounting holes 6b and 7b.

According to the above-mentioned 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.

[0021]

As described above, according to the plunger pump of the present invention, the suction chamber formed in the housing, the plunger storage hole communicating with the suction chamber, and the plunger stored in the plunger storage hole, A pressure chamber that communicates with the plunger housing hole, and a reciprocating motion of the plunger causes a pump for pumping the hydraulic oil sucked into the plunger housing hole from the suction chamber into the pressure chamber as one pump unit. Since a plurality of pump units are coaxially arranged and the pump units are fastened to each other, the plunger pump can be easily assembled and disassembled, and the productivity can be improved.
It is possible to further reduce the cost by minimizing the replacement parts due to the occurrence of processing defects and the like.

[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.

FIG. 3 is a partially enlarged cross-sectional view of a front plunger storage portion of the tandem plunger pump.

FIG. 4 is a partially enlarged cross-sectional view of a plunger storage portion on the rear side of the tandem plunger pump.

5A is a sectional view of the vicinity of a pressure chamber having a check valve of the tandem plunger pump, and FIG. 5B is a front view of the check valve.

6A is a sectional view of the check valve, and FIG. 6B is a sectional view taken along line XX of FIG. 6A.

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

[Explanation of symbols]

 1 ... Tandem plunger pump 2, 3 ... Radial plunger pump (pump unit) 4,5 ... Plunger storage part 6, 7 ... Pressure part 13 ... Drive shaft 20,30 ... Suction chamber 21, 31 ... Bore (plunger storage hole) 40 , 50 ... Plunger

Claims (2)

[Claims] 1. A suction chamber formed in a housing, a plunger housing hole communicating with the suction chamber, a plunger housed in the plunger housing hole, and a pressure chamber communicating with the plunger housing hole. A pump that pumps the hydraulic oil sucked into the plunger storage hole from the suction chamber into the pressure chamber by the reciprocating motion of the plunger is used as one pump unit, and a plurality of pump units are coaxially arranged. A plunger pump characterized in that the units are fastened together. 2. The plunger pump according to claim 1, wherein the pump units are arranged in front and rear, and housings of the front and rear pump units are provided with a plunger accommodating portion forming a plunger accommodating hole, and a pressure portion forming a pressure chamber. Plunger pump characterized by being divided into and mutually fastened.