JPH0318715Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a vane pump.

(Conventional technology and its problems) As a conventional vane pump, for example,
There is a device disclosed in No. 22310 that is equipped as a hydraulic power source for a power steering device of a vehicle. The discharge flow rate of conventional general vane pumps increases in proportion to the rotation speed, and the flow rate supplied to the outside of the pump is controlled to a predetermined value using a separate flow rate adjustment valve. .

However, when such a vane pump is driven by the output of the vehicle's engine, the pump also rotates at high speed when the engine rotates at high speeds, and a large amount of working fluid is discharged from the discharge port of the pump in proportion to this, causing a problem with the flow rate adjustment valve. Since the excess flow rate other than the flow rate regulated and discharged to the outside returns to the suction port, the internal circulation flow rate of the pump increases, resulting in a loss of pump drive energy and an increase in the temperature of the working fluid.

(Means and effects for solving the problem) This invention was made in view of the above-mentioned conventional problems, and its configuration is such that a drive shaft is connected to a body having an internal chamber and one end thereof is connected to the internal chamber. The outer surface of a plurality of vanes inserted radially into the rotor provided at one end of the cam ring can be slidably contacted with the inner surface of the cam ring. Alternatively, in a vane pump that is covered with a pair of side plates each having a discharge port formed therein, and one of the side plates is biased against the vane by a spring, the one side plate is movable in the direction of the rotational axis of the drive shaft. The vane pump is supported by the body, the inner surface of the cam ring has a tapered shape that expands toward the one side plate, and the outer surface of the vane has a shape that matches the tapered shape.

Therefore, when the drive shaft is driven in a low rotation range, the working fluid sucked in from the suction port of the side plate is efficiently discharged from the discharge port of one side plate, and is used for example as a fluid in a power steering device. Supplied to pressure actuators, etc.

For driving in the high rotation range of the drive shaft,
Under the influence of centrifugal force, the vanes are guided by the tapered inner surface of the cam ring, protrude in the direction of the rotational axis of the drive shaft, and move to a position that balances the elastic force of the spring. Thus, a gap is formed between the rotor and one of the side plates to serve as a flow path for the working fluid, and the suction port side chamber and the discharge port side chamber, which are partitioned by each vane, are short-circuited and connected depending on the rotation speed. Create internal leaks. As a result, when the vane pump rotates at high speed, the ratio of the discharge flow rate to the rotational speed can be reduced, and the drive torque of the vane pump can be reduced. Further, when a flow rate control valve is provided and oil is used as the working fluid, the internal circulation flow rate is reduced, so an excessive rise in oil temperature can be suppressed.

(Example) Hereinafter, an example of this invention will be described with reference to FIGS. 1 to 4.

In FIGS. 1 and 2, numeral 1 indicates a body, and body 1 connects front body 2 and rear body 3.
It is constructed by being oil-tightly connected with a plurality of bolts 21 with a ring 20 interposed therebetween, and defines an internal chamber 4. A pair of bearings 5 are installed on the front body 2.
a, 5b and an oil seal 6, a drive shaft 7 is rotatably and oil-tightly supported, and a rotor 8 is splined to one end of the drive shaft 7 facing the internal chamber 4. ing. A plurality of radial slits 8a are formed in the rotor 8 at regular intervals in the circumferential direction, and a vane 9 is slidable radially in each of these slits 8a in the radial direction and the rotation axis direction. It has been inserted.

Reference numeral 10 denotes a cam ring, and its inner surface 10a has an elliptical cam shape in cross section perpendicular to the rotational axis, and tapers in the rotational axis direction toward a side plate 11 (to be described later) to form an elliptic cone shape. The outer surface 9a of each vane 9 forms an inclined surface that matches the inner surface 10a of the cam ring 10 so that it rotates while slidingly contacting the inner surface 10a of the cam ring 10. Further, the outer surface of the rotor 8 has a conical surface that matches the short diameter of the inner surface 10a of the cam ring 10.
One side of the vane 9 is covered with a rear body 3 functioning as a side plate, and the other side is covered with a side plate 11.

In addition, the cam ring 10 and the side plate 1
As shown in FIG. 2, the side plate 11 is positioned with respect to the front body 2 by engaging a pair of upper and lower parallel pins 12a, 12b on its outer peripheral surface. The side plate 11 is slidable in the direction of the rotational axis of the drive shaft 7 while being guided by the side plate 11.
is urged toward the rotor 8 and cam ring 10 by a spring 13.

Reference numeral 14 designates an inlet port formed in the front body 2, which is connected to a fluid tank (not shown), and also communicates with a suction passage 15 formed in the rear body 3, and connects to a pair of suction ports shown by phantom lines in FIG. Mouth 1
6a and 16b. On the other hand, a pair of discharge ports 11a and 11b are formed in the side plate 11, and these discharge ports 11a and 11b are connected to a discharge chamber 4a defined in the internal chamber 4 by the side plate 11 and a flow rate control valve 17, and The discharge chamber 4a is connected to the inlet port 14 and the suction passage 15. Furthermore, the flow control valve 17 is connected to an outlet port (not shown).

A pulley 19 is connected to the lock nut 2 at the other end of the drive shaft 7 with a half-moon key 18 interposed therebetween.
It is fixed at 3.

Next, the effect will be explained.

When the pulley 19 is rotationally driven by the engine of the vehicle, the drive shaft 7 and rotor 8 of the vane pump are rotationally driven, and the vane 9 is pressed against the inner surface 10a of the cam ring 10 by centrifugal force. In the low rotation range of the engine, the suction port 16a of the body 1,
The working fluid oil sucked in from 16b is discharged from the discharge ports 11a and 11b of the side plate 11, passes through the flow rate control valve 17, and almost all of the oil is delivered to the fluid pressure actuator of the power steering system through the outlet port. Sent.

When the rotation speed of the rotor 8, that is, the rotation speed N of the pump increases as the engine speed increases,
As shown in FIG. 3, the vane 9 protrudes and moves toward the side plate 11 along the tapered inner surface 10a of the cam ring 10 to a position where it balances the elastic force of the spring 13 under the influence of centrifugal force. The side plate 11 is pushed out to the right in the figure according to the pump rotation speed N, and the rotor 8 and the side plate 1
1 to form a gap that will serve as a flow path. Therefore, the suction ports 16a, 1 partitioned by each vane 9
The 6b side chamber and the discharge ports 11a and 11b side chambers are directly communicated with each other to cause internal leakage. The results are shown in FIG. In this figure, the vertical axis shows the flow rate Q, and the horizontal axis shows the pump rotation speed N. The solid line A shows the characteristics of the vane pump according to this invention, and the broken line B
2 shows the characteristics of a conventional vane pump, and the dashed line C shows the actual supply flow rate from the outlet port controlled by the flow rate adjustment valve 17. As can be seen from this figure, as the pump rotational speed N increases, the discharge flow rate discharged from the discharge ports 11a and 11b can be decreased within the shaded range. As a result, the internal circulation flow rate of the pump that is not discharged from the flow rate control valve 17 but is recirculated to the suction passage 15 is reduced, and the driving torque of the pump can be reduced accordingly. Furthermore, an increase in the temperature of the working fluid (oil temperature) due to internal circulation of the working fluid of the pump is also suppressed.

(Effect of the invention) As understood from the above explanation, according to this invention, when the vane pump rotates at high speed,
By reducing the ratio of discharge flow rate to rotational speed, the pump drive torque required to supply a certain amount of working fluid can be reduced, resulting in significant savings in drive energy and eliminating the need to use oil as the working fluid. In this case, excessive rise in oil temperature can be suppressed and oil deterioration can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of this invention, Fig. 2 is a view taken along the - line in Fig. 1, Fig. 3 is an explanatory diagram of the action, and Fig. 4 is a line showing flow rate-pump rotation speed characteristics. It is a diagram. 1... Body, 3... Rear body (side plate), 4... Internal chamber, 7... Drive shaft, 8
... Rotor, 9 ... Vane, 9a ... Outer surface, 1
0...Cam ring, 10a...Inner surface, 11...Side plate, 11a, 11b...Discharge port, 12
a, 12b...Pin, 13...Spring, 16
a, 16b...Suction port.

Claims (1)

[Scope of utility model registration request] A drive shaft is supported by a body having an internal chamber with one end facing the internal chamber, and the outer surface of a plurality of vanes inserted radially into the rotor provided at the one end can slide against the inner surface of the cam ring. In the vane pump, both sides of the vane are covered with a pair of side plates each forming a suction port or a discharge port for the working fluid, and one side plate is biased against the vane by a spring. a side plate is supported on the body so as to be movable in the direction of the rotational axis of the drive shaft, an inner surface of the cam ring is provided with a tapered shape that expands toward the one side plate, and an outer surface of the vane is provided with a tapered shape that expands toward the one side plate; A vane pump characterized by having a shape that conforms to a tapered shape.