JP2838551B2 - Hydraulic pump device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic pump device mounted on a vehicle, a construction machine, and the like, and in particular, to an unnecessary supply of pressure oil from a hydraulic pump. And power loss is reduced.

(Prior Art) For example, in a vehicle power steering device,
An initial steering torque is detected, and an assist force commensurate with the magnitude of the torque is applied.

The application of the assist force is performed by supplying pressure oil from a plurality of hydraulic pumps and driving the actuator with the pressure oil.

By the way, the hydraulic pump uses the engine of the vehicle as a power source. Therefore, the discharge amount is determined by the rotation speed of the engine.

(Problem to be Solved by the Invention) According to the above-described conventional configuration, there are the following problems.

That is, unnecessary pressure oil is discharged from the hydraulic pump, causing power loss.

For example, as a power steering device, the higher the speed of a vehicle, the better the steering feeling is "heavy", and from that point of view, a smaller assist force is required.

However, as described above, the hydraulic pump uses the engine as the power source, and the higher the engine speed, the higher the discharge rate, which causes unnecessary discharge of pressure oil and the resulting increase in power loss. Was.

The present invention has been made based on such a point, and an object of the present invention is to eliminate the unnecessary discharge of hydraulic oil from a hydraulic pump, thereby making it possible to reduce power loss. It is to provide a device.

(Means for Solving the Problems) In order to achieve the above object, a hydraulic pump device according to the present invention includes a plurality of hydraulic pumps arranged in parallel and a switching valve provided on a suction side of at least one hydraulic pump. The switching valve switches according to a pressure change between a plurality of hydraulic pumps arranged in parallel and an actuator, or a pressure difference before and after an orifice provided on a discharge side of a hydraulic pump not provided with a switching valve. The opening degree of the suction side of one hydraulic pump is changed.

(Operation) In the hydraulic pump device according to the present invention, a pressure change between a plurality of hydraulic pumps and an actuator arranged in parallel,
Alternatively, the switching valve can be switched by using a pressure difference change before and after the orifice provided on the discharge side of the hydraulic pump not provided with the switching valve, and the opening degree of the suction side of at least one hydraulic pump can be changed.

(Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram of a hydraulic pump device according to the present embodiment, and FIG. 2 is a pressure oil flow rate characteristic diagram.

The hydraulic pumps 1 and 3 are arranged in parallel, and these hydraulic pumps 1 and 3 use an engine (not shown) as a power source. The hydraulic pumps 1 and 3 control the tank 5
The oil inside is sucked and pressurized and supplied to an actuator (not shown).

A check valve 7 is inserted on the discharge side of the hydraulic pump 1, and a switching valve 9 is inserted on the suction side. The switching valve 9 has switching positions a and b, and is normally switched to the switching position b by the spring 11. Thereby, the suction side of the hydraulic pump 1 is open.

On the other hand, when the solenoid 13 is operated, it is switched to the switching position a, and the suction side of the hydraulic pump 1 is throttled by the throttle mechanism 15.

On the other hand, an orifice 17 is interposed on the discharge side of the hydraulic pump 3, and a differential pressure detector 19 is attached to the orifice 17. This differential pressure detector 19 has an orifice 17
If the pressure difference before and after exceeds a predetermined value, that is, if the flow rate reaches a predetermined flow rate, a detection signal S19 is output to the controller 21.

When receiving the detection signal S19, the controller 21 outputs a control signal S21 to the solenoid 13 and activates it.

 The operation will be described based on the above configuration.

First, since the switching valve 9 is initially switched to the switching position b, pressure oil is supplied from both of the hydraulic pumps 1 and 3,
As shown by the solid line in FIG. 2, the number increases in proportion to the number of revolutions of the engine.

FIG. 2 is a diagram showing the flow characteristics of the hydraulic pump 1, the flow characteristics of the hydraulic pump 3, and the flow characteristics in the present embodiment, where the horizontal axis indicates the differential pressure and the vertical axis indicates the pressure oil flow rate.

Next, when the differential pressure of the orifice 17 exceeds a preset value, a detection signal S19 is output from the differential pressure detector 19 to the controller 21.
Is output to The controller 21 outputs a control signal S21 to the solenoid 13 of the switching valve 9 to operate it.

Thereby, the switching valve 9 switches to the switching position a,
The suction side of the hydraulic pump 1 is throttled. As a result, as shown in FIG. 2, the flow rate becomes substantially only by the hydraulic pump 3.

According to the present embodiment, the following effects can be obtained.

First, at high speeds when the engine speed is high,
Unnecessary supply of pressure oil can be prevented. Therefore, power loss can be reduced.

Also, even when the suction skin of the hydraulic pump 1 is throttled by the throttle mechanism 15, a small flow is secured, so that the soundness of the hydraulic pump 1 is not impaired.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a configuration diagram of a hydraulic pump device, in which hydraulic pumps 31 and 33 are arranged in parallel, and the hydraulic pumps 31 and 32 suck and pressurize oil in a tank 35 and supply it to an actuator 37. .

A hydraulic control valve 39 is interposed on the discharge side of the hydraulic pumps 31 and 33.
, An operation lever 41 is connected. An orifice 43 is interposed further on the secondary side of the hydraulic control valve 39.

A check valve 45 is interposed on the discharge side of the hydraulic pump 33, and a switching valve 47 is interposed on the suction side. This switching valve 47 is provided with switching positions a and b.
The position is switched to the switching position a by the spring 49.
Therefore, the suction side of the hydraulic pump 33 is open.

On the other hand, when the solenoid 51 operates,
Switching to the switching position b, the suction side of the hydraulic pump 33 is throttled by the throttle mechanism 53.

A pressure detector 55 is mounted between the hydraulic control valve 39 and the orifice 43. The pressure detector 55 outputs a detection signal S55 to the controller 57 when the pressure of the pressure oil exceeds a predetermined pressure.

When the detection signal S55 is input, the controller 57 outputs a control signal S57 to the solenoid 51 to activate it, and switches the switching valve 47 to the switching position b.

As a result, the suction side of the hydraulic pump 33 is throttled, and pressure oil is supplied only from the hydraulic pump 31.

According to the above configuration, the flow rate of the pressurized oil from the supply changes as shown in FIG. The case shown in FIG. 4 is the case where the engine speed is constant, and the case where the engine speed is increasing is as shown in FIG.

When the predetermined pressure is reached, the switching valve 47 is switched to the switching position b.
And the flow rate becomes substantially only the hydraulic pump 31, so that the pressure drops momentarily below the predetermined pressure as shown by the two-dot chain line in FIG. 6 (a). Then, when the pressure decreases, the switching valve 47 is immediately switched to the switching position a, and the hydraulic oil is discharged from the hydraulic pump 33 again. Therefore, the hydraulic pump 33 discharges or does not discharge the pressure oil before and after the predetermined pressure, and the state becomes unstable.

Thus, once the pressure reaches the predetermined pressure, the controller 57 immediately switches the switching valve even if the pressure falls below the predetermined pressure.
47 is not switched to the switching position a, but is controlled with a dead zone as shown in FIG. 6 (b). Specifically, when the pressure becomes equal to or less than p, the switching valve 47
Is switched to the switching position a so that the hydraulic oil is discharged from the hydraulic pump 33.
The pressure is set lower than when only 31 is used.

As described above, also in the case of the second embodiment, the same effects as in the case of the first embodiment can be obtained.

Next, a third embodiment will be described with reference to FIGS. 7 and 8. FIG.

The hydraulic pumps 61 and 63 are arranged in parallel, and the hydraulic pumps 61 and 63 suck and pressurize the oil in the tank 65 and supply the oil to the actuator 67.

A control valve is provided on the discharge side of the hydraulic pumps 61 and 63.
An operation lever 71 is connected to the control valve 69.

A check valve 73 is interposed on the discharge side of the hydraulic pump 63, and a switching valve 75 is interposed on the suction side. Switching valve
75 has switching positions a and b, and is normally switched to the switching position a by the spring 77.

On the other hand, when the solenoid 79 operates, the position is switched to the switching position b. Thus, the suction side of the hydraulic pump 63 is throttled by the throttle mechanism 81.

The pressure on the discharge side of the hydraulic pump 63 is monitored by a pressure detector 83. When the pressure detector 83 reaches a predetermined pressure set in advance, a detection signal S83 is sent to the controller 85.
Is output.

The controller 85 inputs the detection signal S83 and outputs a control signal S85 to the solenoid 79. Thereby,
The solenoid 79 is actuated and, as already mentioned, the switching valve 75
To the switching position b.

According to the above configuration, the flow rate of the supplied pressure oil changes as shown in FIG. That is, after reaching the predetermined pressure, the pressure oil flow rate decreases.

Next, a fourth embodiment will be described with reference to FIG. 9 and FIG. This is different from the configuration according to the third embodiment in that one hydraulic pump 91 is added and a switching valve 93 is interposed on the suction side of the hydraulic pump 91.

The switching valve 93 is provided with switching positions a and b, and is normally switched to the switching position a by the spring 95. When the solenoid 97 is operated, the switching valve 93 is switched to the switching position b, and the throttle mechanism 99 is operated. Thereby, the suction side of the hydraulic pump 91 is throttled.

When the discharge side pressure reaches the preset A pressure, the switching valve 75 is switched to the switching position b, and the hydraulic pump
Squeeze 63 suction side.

Next, when the pressure further increases and reaches the B pressure, the switching valve 93 is switched to the switching position b, and the suction side of the hydraulic pump 91 is throttled by the throttle mechanism 99.

Therefore, the flow rate of the discharged pressure oil changes as shown in FIG.

If the number of hydraulic pumps is further increased, finer flow control becomes possible, as shown by the broken line in FIG.

Next, a fifth embodiment will be described with reference to FIGS. 11 and 12. FIG.

The hydraulic pumps 101 and 103 are arranged in parallel, and supply the oil in the tank 105 to the cylinder mechanism 107 by the hydraulic pumps 101 and 103. The cylinder mechanism 107 is a cylinder 10
9, a piston 111 reciprocating in the cylinder 109,
And a rod 112 connected to the piston 111.

A control valve 113 is interposed on the discharge side of the hydraulic pumps 101 and 103, and an operation lever 115 is connected to the control valve 113. The control valve 113 has a built-in safety valve, is located at the stroke end position of the cylinder mechanism 107, and exerts its function to prevent the effect of overload.

 Incidentally, reference numeral 117 in the figure denotes a tank.

A check valve 119 is interposed on the discharge side of the hydraulic pump 103, and a switching valve 121 is interposed on the suction side. The switching valve 121 has switching positions a and b, and is normally switched to the switching position a by the spring 123.

When the solenoid 125 is operated, the position is switched to the switching position b, and the suction side of the hydraulic pump 103 is moved to the throttle mechanism 127.
Squeezed by

The discharge side pressure of the hydraulic pumps 101 and 103 is
The detection signal S129 is output to the controller 131 when the pressure reaches a predetermined pressure set in advance. The controller 131 thereby controls the solenoid 125
Control signal S131 to switch the switching valve 121 to the switching position b.

According to the above configuration, at the stroke end position of the cylinder mechanism 107, the safety valve of the control valve 113 releases the pressurized oil, and the pressure reaches the predetermined pressure. Therefore, the switching valve 121 switches to the switching position b, and the hydraulic pressure is reduced. The suction side of the pump 103 is throttled by the throttle mechanism 127, and the pressure oil flow rate decreases as shown in FIG.

Therefore, the same effects as those of the above embodiments can be obtained, and "stall" can be prevented.

Next, a sixth embodiment will be described with reference to FIGS.

The hydraulic pumps 141 and 143 are arranged in parallel.
Pressurized and supplied to the actuator 147.

A check valve 149 is inserted on the discharge side of the hydraulic pump 143, and a switching valve 151 is inserted on the suction side. The switching valve 151 has switching positions a and b, and is normally switched to the switching position a by the spring 153.

On the other hand, an orifice 155 is inserted on the discharge side of the hydraulic pump 141. The primary pressure and the secondary pressure of the orifice 155 act on the sliding parts 157, 159 of the switching valve 151.

Then, when the pressure difference before and after the orifice 155 reaches a predetermined pressure difference, the switching valve 151 switches to the switching position b. The suction side of the hydraulic pump 143 is throttled by the throttle mechanism 160.

In the above configuration, initially, the switching valve 151 is in the switching position a
Therefore, pressure oil is supplied from both of the hydraulic pumps 141 and 143, and increases as the engine speed increases, as shown by the solid line in FIG.

Then, when the pressure difference between before and after the orifice 155 reaches a predetermined value, the switching valve 151 switches to the switching position b, and as a result, as shown by the solid line in FIG. 14, the flow rate of the pressure oil decreases.

Therefore, the same effects as in the above embodiments can be obtained.

Next, a seventh embodiment will be described with reference to FIGS.

The hydraulic pumps 161 and 163 are arranged in parallel.
Pressurized and supplied to the actuator 167.

A control valve 169 is interposed on the discharge side of the hydraulic pumps 161 and 163, and an operation lever 171 is connected to the control valve 169.

A check valve 173 is inserted on the discharge side of the hydraulic pump 163, and a switching valve 175 is inserted on the suction side.
The switching valve 175 has switching positions a and b, and is normally switched to the switching position a by the spring 177.

On the other hand, the discharge-side pressure of the hydraulic pump 161 acts on the sliding portion 179 of the switching valve 175. When the pressure reaches a predetermined pressure, the sliding portion 179 operates and the switching valve 175 is switched to the switching position. b
Switch to. Then, it is stopped down by the stop mechanism 180.

According to the above configuration, the pressure oil flow rate changes as shown in FIG. That is, the flow rate decreases at a predetermined pressure.

Next, an eighth embodiment will be described with reference to FIG. 17 and FIG. This embodiment differs from the seventh embodiment in that one hydraulic pump 181 is added and a switching valve 183 is inserted on the suction side.

The switching valve 183 is normally switched to the switching position a by the spring 185, and is switched to the switching position b by the sliding portion 187 when the discharge pressure reaches a predetermined pressure. Then, it is stopped down by the stop mechanism 189.

In the case of this embodiment, first, when the pressure reaches A, the suction side of the hydraulic pump 163 is throttled. When the pressure reaches a higher B pressure, the suction side of the hydraulic pump 181 is throttled.

 Therefore, the pressure oil flow rate changes as shown in FIG.

By further increasing the number of hydraulic pumps, more detailed control becomes possible, as shown by the two-dot chain line in FIG.

(Effects of the Invention) As described above in detail, according to the hydraulic pump device of the present invention, a pressure change between a plurality of hydraulic pumps arranged in parallel and an actuator, or a discharge side of a hydraulic pump without a switching valve is provided. The switching valve is switched in response to a change in the pressure difference before and after the orifice provided in the above, and the opening of the suction side of at least one hydraulic pump can be changed.

For example, if the suction side of one hydraulic pump is restricted, the discharge amount from that hydraulic pump can be reduced. Therefore, it is possible to adjust the discharge amount itself by the plurality of hydraulic pumps as a whole, so that unnecessary supply of pressure oil and power loss due to the supply can be reduced.

In addition, since the switching valve only needs to have a function of adjusting the opening, the structure of the switching valve and the entire circuit are not complicated.

[Brief description of the drawings]

1 and 2 are views showing a first embodiment of the present invention. FIG. 1 is a configuration diagram of a hydraulic pump device, FIG. 2 is a pressure oil flow characteristic diagram, and FIGS. FIG.
FIGS. 4 and 5 are pressure oil flow rate characteristic diagrams, FIGS. 6 (a) and 6 (b) are diagrams for explaining control widths, and FIGS. FIG. 13 is a diagram showing a third embodiment,
FIG. 8 is a diagram showing the configuration of a hydraulic pump device, FIG. 8 is a diagram showing a hydraulic oil flow characteristic, FIGS. 9 and 10 are diagrams showing a fourth embodiment, FIG. Is the pressure oil flow characteristic diagram,
11 and 12 are views showing a fifth embodiment, FIG. 11 is a configuration diagram of a hydraulic pump device, FIG. 12 is a pressure oil flow characteristic diagram, and FIG.
FIGS. 14 and 15 show a sixth embodiment. FIG. 13 is a block diagram of a hydraulic pump device, FIG. 14 is a pressure oil flow rate characteristic diagram, and FIGS. 15 and 16 show a seventh embodiment. FIG. 15 is a configuration diagram of a hydraulic pump device, FIG. 16 is a diagram of pressure oil flow characteristics, FIG. 17 and FIG.
FIG. 18 is a view showing an eighth embodiment, FIG. 17 is a configuration diagram of a hydraulic pump device, and FIG. 18 is a pressure oil flow rate characteristic diagram. 1,3 ... Hydraulic pump, 9 ... Switching valve, 19 ... Differential pressure detector, 21 ... Controller.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B62D 5/07 F04B 49/00 F15B 11/02

Claims (1)

(57) [Claims] 1. A hydraulic pump comprising a plurality of hydraulic pumps arranged in parallel, and a switching valve provided on a suction side of at least one hydraulic pump, wherein the switching valve comprises a hydraulic pump and an actuator arranged in parallel with each other. The opening degree of the suction side of one hydraulic pump is changed by switching according to the pressure change between the two or the pressure difference before and after the orifice provided on the discharge side of the hydraulic pump without the switching valve. A hydraulic pump device.