JPS5854272B2 - rotary pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the input and output of a rotary pump driven by a prime mover with a large output fluctuation range, and its purpose is to control the rotational speed of the drive shaft of the rotary pump regardless of the rotational speed of the output shaft of the prime mover. By maintaining the output flow rate at a substantially constant value and maintaining the output flow rate at a constant value regardless of the rotational speed of the drive shaft, unnecessary energy consumption by the rotary pump can be effectively eliminated.

For example, in a rotary pump for a power steering system driven by the engine output of a car, when the engine rotates at high speed, the pump also rotates at high speed and discharges a larger amount of fluid than necessary. However, from the point of view of energy consumption, the rotary pump wastes energy by the amount of this discharge flow rate.

In view of these problems, the present invention utilizes the discharge fluid of the conventionally used flow rate control valve, that is, the surplus of the rotary pump discharge flow rate, to increase the effective diameter of the variable pulley attached to the drive shaft of the rotary pump. The feature is that by changing the rotation speed of the rotary pump drive shaft, the rotation speed of the rotary pump drive shaft is maintained at a substantially constant value regardless of the rotation speed of the prime mover output shaft.

Hereinafter, the present invention will be explained based on the drawings.

The drawing shows an input/output control device for a rotary pump for a power steering device of an automobile as an embodiment of the present invention.

In FIG. 1, 1 is an output shaft of an engine (not shown), that is, a prime mover, and a variable pulley support shaft 2 is fixed to the output shaft 1.
A variable pulley 3 is mounted on this support shaft 2.

In this embodiment, the variable pulley 3 is used for belt engagement.
It is composed of a pair of movable pulleys 3a and 3b forming grooves, and each of the movable pulleys 3a and 3b is supported on the support shaft 2 so as to be slidable in the axial direction, with the movable pulleys 3a and 3b being prevented from rotating.

The effective diameter of the variable pulley 3 is equal to that of the pair of movable pulleys 3 a
It is determined by the interval t 3 b; if they are close to each other, the effective diameter increases, and if they are apart, the effective diameter decreases.

A flange formed at the base of the support shaft 2 and one movable pulley 3a
Both rotary pulleys 3a are provided between the flange fixed to the tip of the support shaft 2 and the other movable pulley 3b.

Compression springs, that is, elastic restoring members 4a and 4b are interposed to urge the members 3b toward each other in a direction to increase the effective diameter.

In FIG. 2, 10 is a rotary pump that supplies pressure fluid to an actuator of a power steering device (not shown), 11 is a drive shaft that rotates a rotor 12, and 13 is a fluid tank 14.
15 is a discharge port of the rotary pump 10, which is in communication with the rotary pump 10.

As is well known, pressure fluid proportional to the rotational speed of the drive shaft 11 is discharged from this discharge port.

A variable pulley 16 is mounted on the drive shaft 11, and a belt 17 is wound between the variable pulley 16 and the variable pulley on the motor output shaft 1.

This variable pulley 16 also includes a pair of movable pulleys 16a16b, both rotating pulleys 16a.

16b are supported on the drive shaft 11 so as to be slidable in the axial direction while being prevented from rotating.

A compression spring, ie, an elastic restoring member 18, is interposed between the two rotary pulleys 16a and 16b so as to bias both in the direction of decreasing the effective diameter.

Reference numeral 20 denotes a fluid pressure cylinder that acts in a direction to increase the effective diameter of the variable pulley 16, and in this embodiment, it is attached to a fluid pressure cylinder chamber 21 formed in one movable pulley 16b and to the other movable pulley 16a. A piston 22 is fitted, and when pressure fluid is supplied to this cylinder chamber 21, both rotary pulleys 16 a t 16 b are drawn toward each other and their effective diameter increases.

Reference numeral 25 denotes a pressure fluid delivery port leading to the actuator of the power steering device, and 30 designates the maximum flow rate of the pressure fluid to be delivered to the delivery port 25 to a required constant value by discharging the excess flow rate of the pressure fluid discharged from the delivery port 15. This is a flow control valve that controls the flow rate.

The flow rate control valve 30 in this embodiment is, for example, disclosed in Patent No. 57
It is the same as that described in the patent specification of No. 7450 (Japanese Patent Publication No. 45-1381), and has a spool 31 and an orifice 32.
, a spring 33, etc., and when the flow rate of the pressure fluid sent from the discharge port 15 increases beyond a set value, the spool 31 is pushed to open the discharge hole 34 and the excess flow is directed to the discharge hole 34. The maximum value of the flow rate discharged and thereby sent to the outlet 25 is always maintained at the above-mentioned set value.

This discharge hole 34 serves as a pressure chamber.

That is, the discharge hole 34 communicates with the suction port 13 of the low-replacement pump 10 via the orifice 35, and the surplus flow flowing into the discharge hole 34 is returned to the suction port 13.
Since the pressure inside is maintained at approximately atmospheric pressure, the exhaust hole 34
The pressure inside changes according to the incoming surplus flow.

A pressure control valve 40 is composed of a plug 41, a spool 42, springs 43, 44, etc., and pressure fluid having a pressure proportional to the displacement of the plug 41 is taken out from an output port 45.

This output port 45 is connected to a flow path 46 opened to the drive shaft 11.
It is communicated with the cylinder chamber 21 of the fluid pressure cylinder 20 via.

The input port 47 communicates with the discharge hole of the flow control valve 34, ie, the pressure chamber 34, so that the plug 41 is displaced in proportion to the pressure within the pressure chamber 34.

The fluid supply port 48 is connected to the discharge port 15 of the rotary pump 10.
The discharge fluid of the low-pressure pump 10 is used as a pressure medium for the pressure control valve 40.

The discharge port 49 communicates with the suction port 13 of the low-pressure pump 10, and the discharge flow is returned to the suction port 13.

Next, the operation of the device of the present invention will be explained.

First, the rotation speed Np of the drive shaft 11 of the rotary pump 10, the discharge flow rate Qa discharged from the discharge port 15, and the discharge port 25.
FIG. 5 shows the relationship between the flow rate Qb and the flow rate Qb.

The discharge flow rate Qa changes in proportion to the rotation speed Np.

The delivery flow rate Qb changes in proportion to the rotational speed Np between 0 and Np1, but in the region where the rotational speed Np is Np1 or more, it becomes a constant value regardless of the rotational speed Np due to the action of the flow rate control valve 30. maintained.

Therefore, the flow rate (Q
a-Qb) is O when the rotational speed Np is between O and Np1, but changes in proportion to a change in Np in a region where the rotational speed Np is Npt or more.

Therefore, the pressure in the pressure chamber 34 varies from 0 to Np as the rotational speed Np increases.
1, the pressure is maintained at atmospheric pressure, but in the region of Np1 or more, it changes according to the rotation speed Np, and from the output port 45 of the pressure control valve 40, the pressure fluid supplied from the discharge port 15 of the rotary pump 10 is converted into a pressure proportional to the pressure in the pressure chamber 34 and output.

The pressure fluid output from this pressure control valve 40 acts on the cylinder chamber 21 of the fluid pressure cylinder 20, and the elastic restoring member 1
The fluid pressure cylinder 20 is operated in the direction of increasing the effective diameter of the variable pulley 16 and decreasing the effective diameter of the variable pulley 3 against the forces generated by B, 4a, and 4b.

If the effective diameter of the variable pulley 16 increases and the effective diameter of the variable pulley 3 decreases, the rotation speed Np of the drive shaft 11 of the rotary pump 10 with respect to the rotation speed Ne of the prime mover output shaft 1 decreases.

Therefore, in the region where the rotational speed Np exceeds NpI, the reduction ratio of the rotational speed Np to the rotational speed Ne of the prime mover output shaft 1 changes in the direction in which the reduction ratio increases as the rotational speed Np increases, as the rotational speed Np changes. do.

To summarize this, when the rotational speed Ne is between O and Ne1, the rotational speed Np changes between O and Np1 in proportion to the rotational speed Ne, and the delivery flow rate Qb also changes from O to Np1 in proportion to the rotational speed Ne. Qbl, and in the region where the rotational speed Ne exceeds Ne1, the rate of change of the rotational speed Np is extremely lower than the rate of change of the rotational speed Ne, and the increase in the rotational speed Np is small, and the delivery flow rate Qb is maintained at a constant value Qb1 regardless of the rotational speed Ne.

These relationships are shown in FIG.

Naturally, Qb1 is set to the maximum required amount. As explained above, the present invention suppresses the increase in rotational speed of the rotary pump and maintains the delivery flow rate at a constant value after the delivery flow rate of the rotary pump reaches the maximum required flow rate. energy consumption can be prevented.

Then, the variable pulley for controlling the rotation speed of the rotary pump is operated by the fluid pressure cylinder, and this fluid pressure cylinder is operated based on the discharge flow rate of the flow control valve for controlling the delivery flow rate of the rotary pump. The rotation speed of the pump is accurately reflected in the effective diameter of the variable pulley.

Furthermore, since the delivery flow rate of the rotary pump is controlled by a flow rate control valve, it is maintained constant regardless of variations in the rotational speed of the rotary pump.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a sectional view of the variable pulley on the motor output shaft side, FIG. 2 is a longitudinal sectional view of the rotary pump, and FIG. 3 is a sectional view of FIG. 2. , FIG. 4 is a diagram showing the relationship between the rotation speed of the rotary pump and the delivery flow rate of the rotary pump, and FIG. 5 is a diagram showing the relationship between the rotation speed of the prime mover output shaft, the rotation speed of the rotary pump, and the delivery flow rate. 1... Prime mover output shaft, 3... Variable pulley, 4a. 4b...Elastic restoring member, 10...Rotary pump, 11...Rotary pump drive shaft,
15...Discharge port, 16...Variable pulley, 17...■Belt, 20...Fluid pressure cylinder, 25...Discharge port , 30...
Flow rate control valve, 34... Pressure chamber, 40...
・Pressure control valve.

Claims (1)

[Claims] 1 The output shaft of the prime mover is equipped with a variable pulley that is biased by an elastic restoring member in the direction of increasing the effective diameter, and the drive shaft of the rotary pump is connected to the variable pulley of the prime mover by a belt and is equipped with a hydraulic cylinder. A variable pulley is installed which is biased in the direction of increasing the effective diameter by the rotary pump, and a flow control valve is interposed in the discharge flow path of the rotary pump to discharge the surplus flow when the discharge flow exceeds a certain value. A pressure chamber for converting the discharged surplus flow into pressure is formed in the discharge flow path of the rotary pump, and a pressure corresponding to the pressure in the pressure chamber is generated in the fluid supply flow path of the fluid pressure cylinder. An input/output control device for a low-pressure pump, characterized by interposing a pressure control valve.