JP2954244B2 - 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 faster the vehicle, the better the steering feeling is "heavier".
From that viewpoint, the assist force can be small.

However, as already mentioned, hydraulic pumps use the engine as a power source, and the discharge rate increases as the engine speed increases, causing unnecessary pressure oil discharge 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 one or more hydraulic pumps arranged in parallel, and a switching valve provided on a suction side of at least one hydraulic pump. A vehicle speed detecting means for detecting the speed of the vehicle, and a controller for switching the switching valve based on a detection signal from the vehicle speed detecting means to adjust the supply of pressure oil in response to a change in vehicle speed. Is characterized in that a throttle opening degree equal to or larger than a predetermined amount is always maintained.

(Operation) The vehicle speed is detected by the vehicle speed detecting means. A detection signal from the vehicle speed detection means is input to a controller, and the controller switches the switching valve based on the detection signal.

By switching the switching valve, the flow rate of the pressure oil discharged from the hydraulic pump is adjusted with respect to the change in the vehicle speed,
This suppresses unnecessary supply of pressure oil and power loss due to the supply.

(Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. In this embodiment, the present invention is applied to a vehicle.

FIG. 1 is a configuration diagram of a hydraulic pump device according to the present embodiment, in which two hydraulic pumps 1, 3 are arranged in parallel. These hydraulic pumps 1 and 3 suck and pressurize oil in the tank 5 and supply it to an actuator (not shown). Thereby, an assisting force at the time of steering is applied to a power steering device (not shown).

A switching valve 7 is interposed on the suction side of the hydraulic pump 3. The switching valve 7 has two switching positions a and b. In the switching position a, the suction side of the hydraulic pump 3 is opened. In the switching position b, the suction side of the hydraulic pump 3 is opened. Is stopped down by the stop mechanism 8.

In the normal state, the switching position a is set by the spring 9.
, And is selectively switched to the switching position b by the operation of the solenoid 10.

The rotation speed of the engine 13 of the vehicle 11 is constantly detected by the rotation speed detecting means 15. In this embodiment, the rotation speed of the engine 13 of the vehicle 11 is regarded as the vehicle speed, and the switching valve 7 is switched according to the vehicle speed.

That is, the detection signal S15 from the rotation speed detection means 15 is
Is input to the controller 17, and the controller 17
When the number of revolutions of the engine 13 reaches a predetermined value, a control signal S17 for operating the solenoid 10 is output.

A check valve 19 is interposed on the discharge side of the hydraulic pump 3.

 The operation will be described based on the above configuration.

First, when the rotation speed of the engine 13 is lower than a preset rotation speed, the switching valve 7 is in a state as shown in the figure and has been switched to the switching position a.

Therefore, pressure oil is discharged from both the hydraulic pumps 1 and 3 and supplied to the actuator. This will be described with reference to FIG. In FIG. 2, the horizontal axis represents the number of revolutions of the engine 13, and the vertical axis represents the discharge amounts of the hydraulic pumps 1 and 3 (diagrams I and II).
This shows the change.

Since the oil is first discharged from both the hydraulic pumps 1 and 3, the sum of the discharge amounts of the two is the discharge amount (diagram III).

Next, when the number of revolutions of the engine 13 exceeds a preset value, the controller 17 switches the switching valve 7 to the switching position b. As a result, the discharge amount of the hydraulic pump 3 is greatly limited, and almost the discharge amount of the hydraulic pump 1 alone.

Therefore, there is no fear that unnecessary pressure oil is supplied and power loss increases.

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

First, it is possible to prevent unnecessary discharge of pressure oil, particularly, unnecessary discharge of pressure oil when the rotation speed of the engine 13 becomes high and the vehicle speed of the vehicle 11 becomes a preset value. . Thereby, power loss can be reduced.

Further, when the switching valve 7 is switched to the switching position b, a slight flow of the pressure oil is compensated, which is effective in maintaining the soundness of the hydraulic pump 3.

Next, a second embodiment will be described with reference to FIGS. In this embodiment, the present invention is applied to a configuration including only one hydraulic pump 3, and the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. .

At first, the switching valve 7 is in a state of being switched to the switching position a as shown in the figure. The hydraulic pump 3 sucks and pressurizes oil in the tank 5 and supplies the oil to an actuator (not shown).

The rotation speed of the engine 13 is determined by the rotation speed detection means 15.
It is constantly monitored and input to the controller 17 as a detection signal S15. If the rotation speed of the engine 13 exceeds a preset value, the controller 17
Outputs a control signal S17 to the solenoid 10. As a result, the solenoid 10 is operated, and the switching valve 7 is switched to the switching position b.
And the discharge of the pressure oil is restricted.

This will be described with reference to FIG. As shown in FIG. 4, until the rotation speed of the engine 13 exceeds a preset value, the discharge amount increases in proportion to the rotation speed of the engine 13 and exceeds the preset value. By the way, it becomes almost zero.

Therefore, unnecessary pressure oil discharge and power loss due to the discharge can be reduced.

Next, the third embodiment is illuminated with reference to FIG. 5 and FIG. This embodiment uses a vehicle as a means for detecting a vehicle speed.
The rotation number of the rear wheel 11 is detected by a rotation number detecting means 23. Other configurations are the same as those in the first embodiment, and description thereof will be omitted.

At first, the switching valve 7 is switched to the switching position a, and therefore, the hydraulic oil is discharged from both the hydraulic pumps 1 and 3, and the discharge amount increases as the rotation speed of the rear wheel 21 increases. To go.

When the rotational speed of the rear wheel 21 exceeds a preset value, the control valve 7 switches to the switching position b. Thereby, the discharge amount of the hydraulic oil from the hydraulic pump 3 becomes substantially zero, and becomes the discharge amount of only the hydraulic pump 1 as shown in FIG.

Incidentally, the present invention is not limited to the first to third embodiments.

For example, the number of hydraulic pumps may be three or more.

Further, in each of the embodiments described above, the present invention is applied to the hydraulic pump for assisting the power steering device of the vehicle. However, the present invention is not limited to this.

(Effect of the Invention) As described above in detail, according to the hydraulic pump device of the present invention, the discharge of the hydraulic oil from the hydraulic pump is adjusted according to the vehicle speed of the vehicle, so that the unnecessary discharge of the hydraulic oil is prevented. By limiting, power loss can be reduced.

Further, the switching valve is configured to always maintain the throttle opening degree equal to or larger than a predetermined amount, so that the hydraulic pump is always supplied with oil. If the oil is supplied in this way, the soundness of the hydraulic pump can be maintained.

[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 characteristic diagram showing a flow rate characteristic of the hydraulic pump, and FIGS. FIG. 4 is a view showing a second embodiment, FIG. 3 is a structural view of a hydraulic pump device, FIG.
FIG. 5 is a characteristic diagram showing a flow rate characteristic of a hydraulic pump, FIGS. 5 and 6 are views showing a third embodiment, FIG. 5 is a configuration diagram of a hydraulic pump device, and FIG. FIG. 1,3 ... Hydraulic pump, 7 ... Switching valve, 11 ... Vehicle, 13 ...
... engine, 15 ... rotation speed detection means (vehicle speed detection means),
17 ... Controller.

Claims (1)

(57) [Claims] 1. One or more hydraulic pumps arranged in parallel, a switching valve provided on the suction side of at least one hydraulic pump, vehicle speed detecting means for detecting the speed of the vehicle, A controller that switches the switching valve based on a detection signal to adjust the supply of pressure oil in response to a change in vehicle speed, wherein the switching valve is configured to always maintain a throttle opening of a predetermined amount or more. And hydraulic pump device.