JPS648194B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in vane pumps used in vehicle power steering systems and the like.

To explain a conventional vane pump with reference to FIGS. 1 to 7, first, a pump shaft 2 is rotatably supported in a pump housing 1, and is sandwiched between the pump housing 1 and a cover plate 3.
A rotor 4 rotated by a pump shaft 2 and a cam ring 5 surrounding the rotor 4 are disposed.

The pump housing 1 includes a high pressure chamber 6 having an arcuate tubular body, a discharge port communication passage 7 extending from the high pressure chamber 6 and communicating with a flow control valve (not shown), and a pair of discharge ports also communicating with the high pressure chamber 6. The ports 8, 8 are formed in advance by casting with a casting core 9 consisting of a main body portion 6', a projecting portion 7' extending from its outer periphery, and side protrusions 8', 8' as shown in FIG. It is integrally molded into the housing 1.

The discharge ports 8, 8 open to the outer wall of the high pressure chamber 6, which forms a part of the sliding surface 10 of the pump housing 1 that comes into sliding contact with the rotor 4, and there is also a suction port 1 therein.
1 and 11 are formed as dents. Further, the remaining sliding surface 10 of the pump housing 1 is provided with an annular groove 13 through which the pressure oil in the high pressure chamber 6 is guided through a plurality of perforations 12, and a ring groove 13 is provided in which the pressure oil in the high pressure chamber 6 is guided from the suction port 14 to the suction ports 11, 11. A suction port communication passage 16A for supplying oil to the pair of suction ports 15, 15 on the cover plate 3 side is also opened.

Both contact surfaces 17 and 18 of the cam ring 5 are connected to the sliding surfaces 10 and 18 of the pump housing 1 and the cover plate 3, respectively.
It has the same external shape as 19, and is connected to the suction port communication passage 16A of the pump housing 1 and the cover plate 3.
A passage 16B that communicates with the suction port communication passage 16C of
penetrates.

The sliding surface 19 of the cover plate 3 has a bifurcated passage 16 branching into two directions from the suction port communication passage 16C.
The outlets of D and 16E open as suction ports 15 and 15, and the suction ports 15 and 15 are connected to the suction ports 11 and 16 provided on the sliding surface 10 of the pump housing 1, respectively.
Confront 11.

A large number of vanes 20 are arranged radially on the rotor 4, and these vanes 20 are slidably accommodated in the guide grooves of the rotor 4, and the cam ring 5 The oil sump groove 21 is formed so as to extend until it comes into close contact with the cam surface 22 under the action of rotational centrifugal force of the rotor 4 in response to pressure to improve contact followability on the inner circumferential surface of the pump housing. It communicates with the annular groove 13 of No. 1.

Therefore, the hydraulic oil sucked from the suction port 14 passes through the suction port communication passages 16A to 16C,
The flow is divided into two by forked passages 16D and 16E, and is led to suction ports 15 and 11, and is discharged to discharge port 8 by compression and expansion of a working chamber partitioned by rotor 4, cam ring 5, and vane 20. It is sent into the high pressure chamber 6.

At this time, a part of the pressure oil in the high pressure chamber 6 is guided to the annular groove 13 through the plurality of perforations 12, enters the oil sump groove 21 of the rotor 4 communicating therewith, and acts on the base of the vane 20. The vane 20 is pressed against the cam surface 22 of the cam ring 5 and made to follow the cam surface 22 of the cam ring 5.

Most of the pressure oil in the high pressure chamber 6 passes through the discharge port communication passage 7 and is subjected to flow control by a flow control valve (not shown), and then flows through the discharge port 2.
It is sent to the outside from 3.

The drill hole 12 communicating the above-mentioned high pressure chamber 6 and the annular groove 13 is drilled obliquely from the sliding surface 10 side during processing of the pump housing 1, but at that time, burrs are not formed on the high pressure chamber 6 side. Sometimes you can't get rid of it.

During use of the vane pump, the burr may move away from the end of the borehole 12, pass through the high pressure chamber 6, and get caught in the flow control valve, causing malfunction of the float control valve.

The present invention is aimed at solving the above-mentioned problems, and involves separately sintering and molding the disk-shaped portion that reaches the high pressure chamber from the sliding surface of the pump housing, and then integrating the disk-shaped portion into the pump housing by press-fitting or the like. The object of the present invention is to provide a vane pump that is easy to process and prevents defects caused by processing burrs.

Embodiments will be described below based on the drawings, and in FIGS. 8 and 9, the same reference numerals are given to substantially the same parts as in FIGS. 1 to 7.

As shown in FIGS. 8 and 9, the pump housing 1 forms a circular recess 24 from its sliding surface 10 with the rotor 4.
is a diameter that is slightly larger than the distance between the outer wall of the high pressure chamber 6 that forms part of the sliding surface 10 and the depth H reaching the part 6A of the high pressure chamber 6, and the opposing outer sides 8A and 8A of the discharge port 8. It has D.

A disk body 25, which is a disk-shaped portion, is fitted into this circular recess 24, and the disk body 25 has a portion 6A of the high pressure chamber, and discharge ports 8, 8 communicating therewith. The annular groove 13, a small hole 26 communicating the annular groove 13 with the high pressure chamber 6, and a portion 11A of the suction port 11 forming a recess are integrally sintered and formed. Here, in FIGS. 8 and 9, the groove means consists of the annular groove 13 and small holes 26.

In order to fit the disc body 25 into the circular recess 24, the pump housing 1 is kept at room temperature or heated.
This is done by cooling the disc body 25 and press-fitting it, and this so-called cold-fitting provides an extremely strong bonding force under normal conditions. Therefore, even if high pressure is generated in the high pressure chamber 6 due to the discharged oil, the pressing force against the disc body 25 is applied to the fitting surface of the disc body 25 and the diameter D of the circular recess 24, so that no pressure is applied to the pump housing 1. The tensile stress received by the four bolts (not shown) that fasten the cam ring 5 and the cover plate 3 together is very small, and is caused by the high pressure between the cam ring 5 and the rotor 4 or between the cam ring 5, the cover plate 3, and the pump housing 1. Only the bending stress due to the pressure gradient in the leak area between the two is applied.

Alternatively, instead of the press-fitting described above, the disk body 25 is fitted into the circular recess 24, and an adhesive (for example, an anaerobic adhesive) is applied to this fitting part, so that the adhesive is fitted by capillary action. The two 25 and 24 may be integrated by utilizing penetration into the gap and hardening.

According to this method, there is an advantage that not only the problem of residual stress on the pump housing 1 does not occur, but also the disk body 25 does not bend or deform, compared to the above-mentioned press-fitting method. Another advantage is that processing and dimensional accuracy management (fitting dimensional management) becomes easier.

As explained above, according to the present invention, the disk-shaped portion that reaches the high pressure chamber from the sliding surface of the pump housing is sintered and formed separately, and is inserted and fixed into the pump housing to be integrated. This has the effect of reducing the number of man-hours required for machining the pump housing, eliminating problems caused by machining burrs, and reducing the size of the bolts that fasten the pump housing, cam ring, and cover plate together.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of the conventional device, Fig. 2 is a left side view of the pump housing shown in Fig. 1, Fig. 3 is a perspective view showing the casting core, which is the main part of Fig. 1, and Fig. 4 is Figure 5 is a left side view of the cam ring in Figure 1, Figure 6 is a right side view of the cover plate in Figure 1, Figure 7 is a perspective view of the rotor in Figure 1. 8 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 9 is a left side view of the pump housing shown in FIG. 8. 1...Pump housing, 3...Cover plate,
4... Rotor, 5... Cam ring, 6... High pressure chamber, 7...
Discharge port communication passage, 8...Discharge port, 9...Casting core, 10...Sliding surface, 11...Suction port, 12...Drilled hole, 13...Annular groove, 14...Suction port, 15...Suction port, 16A to 16E ...Discharge port communication passage, 20
...Vane, 21...Oil sump groove, 23...Discharge port, 24...
Circular recess, 25... disc body, 26... small hole.

Claims (1)

[Claims] 1 The rotor and cam ring are sandwiched between the pump housing and the cover plate, and the pump discharge pressure is guided to the base end of vanes arranged radially on the rotor to follow the cam ring, while a high pressure chamber is molded inside the pump housing. At the same time, groove means for guiding the pump discharge pressure to the discharge port and the base end of the vane is formed on the sliding surface of the pump housing to communicate with the high pressure chamber, and the body side suction port is formed in a recessed portion. In the vane pump, the rotor is opposed to the suction port provided in the cover plate with the rotor interposed therebetween, and the disc-shaped portion including the discharge port is arranged at a depth reaching the high pressure chamber from the sliding surface of the pump housing. sintering and forming a separate body, and forming groove means in this disk-shaped portion to guide the pump discharge pressure to the base end of the vane;
A vane pump characterized in that the disc-shaped portion is inserted into and fixed to the pump housing and integrated therewith.