JPH02108866A - Radial piston rotary pump - Google Patents

Abstract

PURPOSE:To properly prevent scorching and restrain a noise level by providing a check valve within a communication pipe in a valve shaft for allowing a flow into a delivery port and preventing a back flow. CONSTITUTION:A fluid pressurized with a piston 14 in a pump chamber moving from the intake slot 11c of a valve shaft 11 to the delivery slot 11d, flows to a delivery port 11b via a communication hole 11e on a valve shaft 11 and a check valve 23 fitted thereto. As a result, a pressing force due to the fluid drops and the partial contact of a rotor 13 with the valve shaft 11 is restrained, thereby properly preventing scorching and a noise when the pump chamber becomes directly open to the slot 11d. In addition, an ordinary pumping effect is obtained and the rotor 13 rotates smoothly without any partial contact with the valve shaft 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a radial piston rotary pump that sucks in and discharges working fluid.

(Prior art) This type of pump is disclosed in Japanese Patent Application Laid-Open No. 61-258977, for example.
The shape of the suction slot and the discharge slot is shown in the above publication, and the shape of the suction slot and the discharge slot is such that the rotor does not come into strong pressure contact with a part of the outer periphery of the valve shaft due to the fluid pressure in the pump chamber during pump operation due to the rotation of the rotor. has been identified.

(Problem to be solved by the invention) By the way, when the pump starts operating (starting), the pressure in the discharge port is not at the set value and is low, so the pressure in the discharge slot does not push up the rotor sufficiently. If this is not achieved, the rotor may come into partial contact with the valve shaft due to the pressing force of the fluid pressurized in the pump chamber that moves from the suction slot to the discharge slot of the valve shaft, causing seizure. Additionally, when the pump chamber opens to the discharge slot, the high pressure fluid within the pump chamber is suddenly depressurized, causing pressure fluctuations and noise. Such a phenomenon can be noticeable in pumps with high set discharge pressures.

(Means for Solving the Problems) The present invention has been made by focusing on the above-mentioned problems, and in the radial piston rotary pump of the above-described type, one end is opened at the discharge port and the other end is opened at the above-mentioned radial piston rotary pump. The valve shaft is provided with a communication hole opening in the outer peripheral wall of the valve shaft that transitions from the suction slot to the discharge slot, and a check valve is provided in the communication hole to allow flow to the discharge port and prevent reverse flow. There are certain characteristics.

(Actions and Effects of the Invention) In the pump according to the present invention configured as described above,
At the time of startup, fluid pressurized by the piston in the pump chamber that moves from the suction slot to the discharge slot of the valve shaft flows to the discharge port through the communication hole provided in the valve shaft and the check valve interposed therein. For this reason,
The pressing force caused by the same fluid is reduced, suppressing the rotor's uneven contact with the valve shaft, properly preventing seizure, and at the same time suppressing noise when the pump chamber opens directly to the discharge slot. .

(Example) An embodiment of the present invention will be described below based on the drawings.

The pump shown in Figure 1 has a discharge pressure of 200 kgf/cm.
The valve shaft 11 is integrally fixed to the housing 12 and has a suction port lla, a discharge port llb, and a suction slot llc for sucking and discharging working liquid. and a discharge slot lid, and a rotor 13 is rotatably provided on the inner end thereof.

As shown in FIGS. 1 and 2, the rotor 13 rotates clockwise in FIG. 2 about the valve shaft 11, and is rotationally driven by a drive shaft (not shown). There is. Further, the rotor 13 is provided with five cylinders 13a to 13a arranged radially at equal intervals in the circumferential direction, and a piston 14 is assembled to each cylinder 13a. Each piston 14 is connected to each cylinder 13a.
It is slidably inserted into the cylinder in the axial direction (rotor radial direction), and has a suction slot llc and a discharge slot 11.
A pump chamber R is formed which selectively communicates with d. Further, each piston 14 is urged outward by a spring 15, and its outer end is in sliding contact with a cam ring 17 via each shoe 16.

The cam ring 17 is provided eccentrically with respect to the rotor 13 on the outer periphery of the rotor 13 (the amount of eccentricity is exaggerated in FIG. 2), and is rotated by the housing 12 via a pair of bearings 18 and 19. possible to assemble. In addition, between the outer race of both bearings 18 and 19 and the cam ring 17,
Leaf spring 21 elastically restricts axial movement of rotor 13
, 22 are provided.

A highly wear-resistant bushing 13b is press-fitted inside the rotor 13 and is fixed to be rotatable integrally with the rotor 13, and the bushing 13b has five cylinders 1
In order to form the openings 3a to 13a, five cylinder ports 13c to 13c smaller than the cylinder diameter are provided. By the way, the working liquid flows through the suction port 11a, the suction slot 11C, and the cylinder port 13c during the suction stroke.
It is sucked into the cylinder 13a through the cylinder port 13C1 and the discharge slot 11 from the cylinder 13a during the discharge stroke.
d, is discharged through discharge port llb. Therefore, the shape of the suction slot llc is selected so that the timing of opening and closing between the cylinder port 13c and the cylinder 13a and the suction port lla is appropriate. That is, the discharge is completed at the specified pressure of 200 kgf/cm2, the liquid in the cylinder 13a is closed by the valve shaft 11, and then the piston 14 rises (moves to the outer periphery) during the suction stroke.
When the liquid at a pressure of 200 kgf/cm2 in the cylinder 13a expands and just drops to the pressure of the liquid to be sucked, that is, atmospheric pressure, the suction slot 11C and the cylinder port 13c are opened. Further, the position where both 11c and 13C are closed is the time when the suction stroke is completed. Next, the discharge stroke begins, and the discharge slot 11d and cylinder port 13
c is opened when the pressure inside the cylinder 13a is 200 kgf/c due to the downward movement of the piston 14 (movement toward the inner circumference).
It is selected at the time when it is compressed to m2. However, liquids such as oil are nearly incompressible, so even a small amount of compression can cause a significant increase in pressure. Further, the position where both 11d and 13C are closed is the time when the discharge stroke is completed. In this way, when liquid is sucked in at atmospheric pressure and discharged at a pressure of 200 kgf/cm2, pressure fluctuations when the cylinder port 13c is opened and closed can be almost eliminated. In addition, the intake slot
The depths of the slots c and discharge slot lid are made relatively small so that the bending strength of the valve shaft 11 is not reduced due to their provision.

Furthermore, in this embodiment, as shown in FIG.
A communication hole 11e is provided in the valve shaft 11,
A check valve 23 is installed in this communication hole lie. The communication hole lie is a stepped hole, and opens to the discharge port llb at the large diameter end, and opens to the suction slot llc at the small diameter end.
The valve shaft 11 transitions from the discharge slot lid to the discharge slot lid.
There is an opening in the outer peripheral wall. The check valve 23 includes a ball valve element 23a seated on a stepped portion of the communication hole lie, and a spring 23 that biases the ball valve element 23a toward the stepped portion.
b, and a cylindrical retainer 23 that stops this spring 23b.
c, which allows flow to the discharge port llb and prevents backflow.

In the pump configured as above, when starting the pump,
The liquid pressurized by the piston 14 in the pump chamber R moving from the suction slot 11C of the valve shaft 11 to the discharge slot lid passes through the communication hole lie provided in the valve shaft 11 and the check valve 23 interposed therein to the discharge port llb. flows to Therefore, the pressing force caused by the same liquid is reduced, the uneven contact of the rotor 13 against the valve shaft 11 is suppressed, and seizure is appropriately prevented, and at the same time, the pump chamber R opens directly to the discharge slot lld. noise is suppressed. Note that when the pressure in the discharge port 11b exceeds the pressure of the liquid pressurized by the piston 14 in the pump chamber R that moves from the suction slot 11c of the valve shaft 11 to the discharge slot lid, the liquid stops flowing through the communication hole 11e. , normal pump operation is obtained,
The rotor 13 rotates smoothly with balanced pressure without hitting the valve shaft 11 unevenly.

In addition, when carrying out the present invention, as shown in FIG.
3, it is also possible to provide the communication hole 11f and the check valve 24.

The communication hole 11f is a stepped hole, and opens into the suction port 11a at its small diameter end, and opens into the outer circumferential wall of the valve shaft 11 transitioning from the discharge slot lid to the suction slot llc at its large diameter end. The check valve 24 is composed of a ball valve element seated on the step of the communication hole 11f, a spring that urges the ball valve element toward the step, and a cylindrical retainer that stops this spring. Flow to 11a is blocked and reverse flow is allowed.

Therefore, in this case, when starting the pump, the above-mentioned effect can be obtained on the side transitioning from the suction slot llc to the discharge slot lid, and the discharge slot lid
The suction port l on the side transitioning from the suction slot llc
The effect that liquid flows from la to the pump chamber R through the communication hole 11f and the check valve 24 is obtained, and not only the rotor pressing force due to positive pressure but also the rotor attracting force due to negative pressure can be eliminated, and the rotor 13 It is possible to further suppress uneven contact of the valve shaft 11 with the valve shaft 11.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a radial piston rotary pump according to the present invention, FIG. 2 is a cross-sectional view of the main part of FIG. 1, and FIG. 3 is a cross-sectional view of the main part showing a modification. Explanation of symbols 11...Valve shaft, lla...Suction port,
llb...Discharge port, llc...Suction slot,
lld...Discharge slot, lie/communication hole, 12...
・Housing, 13... Rotor, 13a... Cylinder, 14... Piston, 15... Spring, 17...
...Cam ring, 23...Check valve, R...Pump chamber. Applicant: Nippondenso Co., Ltd. (1 other person) Agent: Patent attorney Teru Hase (1 other person) JJ-, L. v capital is neck 1 ″ ・ ・ ・ ・ O＼ , h = 1 ,, L ・h ward・dan・ ~ , 0 0 ℃ 0 ・ d+
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Claims (1)

[Claims] a valve shaft that is integrally provided in the housing and has a suction port and a discharge port that suck and discharge working fluid, and a suction slot and a discharge slot; a rotor that is rotatably provided in the housing and rotates about the valve shaft; a cam ring provided eccentrically with respect to the rotor; a piston that is slidably fitted into a cylinder provided radially on the rotor to form a pump chamber that selectively communicates with the suction slot and the discharge slot; A radial piston rotary pump comprising a spring that biases a piston toward the cam ring,
A communication hole is provided in the valve shaft that opens at one end to the discharge port and opens at the other end in the outer circumferential wall of the valve shaft transitioning from the suction slot to the discharge slot, and the communication hole is connected to the discharge port in the communication hole. A radial piston rotary pump characterized by being provided with a check valve that allows the flow of water and prevents reverse flow.