JPH09151842A - Constant flow rate discharge hydraulic pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic pump for discharging a constant flow rate (i.e., constant flow rate discharge hydraulic pump) capable of generating high pressure and never overheated at the time of a low engine speed or low capacity efficiency. SOLUTION: This internal gear pump type hydraulic pump is provided with an external tooth pinion 2, an internal gear 3 rotated together with the pinion 2, crescent-shaped filling members 4.1, 4.2 arranged between the pinion 2 and the internal gear 3, a stop pin supporting the filling members 4.1, 4.2, and an entrance for introducing or discharging the flow of additional oil such as cooling oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pump for delivering a constant flow rate, and more particularly to an internal gear pump according to the preamble of claim 1.

[0002]

Machines of this kind are known from many publications. For example, German Patent Application Publication No. 43222
With reference to JP-A-39, constant flow hydraulic pumps are characterized by a housing having a working medium inlet and a working medium outlet as far as the internal gear pumps are concerned.

An external gear pinion and an internal gear that rotates together with the pinion are mounted in the housing. A filling member is provided between the pinion and the internal gear, the filling member being supported by the tooth tips of the pinion and the internal gear in a sealed state and affecting the sealing of the pressure chamber with respect to the suction chamber.

[0004]

Despite the object of the present invention to be a pressure pump of this kind, the seal between the suction chamber and the pressure chamber is incomplete as it is. This means
This means that a certain amount of leaked oil flows back from the suction chamber to the pressure chamber again, which is of course not preferable.
The ratio of leaked oil to the total amount of oil supplied is called capacity efficiency. Pumps of this kind are often used with rotationally controlled drive power. Hydraulic pumps often rotate at low speeds to produce high pressure. Under such operating conditions, the capacity efficiency is low, below 50%.

As is generally known, the temperature of oil rises while passing through the gap. This is fine as long as it is capacity efficient. However, the capacity efficiency is 50
When below%, this means that some amount of oil is continuously contained in the pump. for that reason,
Circulation occurs inside it. Furthermore, this means that the amount of heat generated during the operation of the pump is no longer adequately damped and remains in the pump. As a result, heat builds up within the pump, causing the pump to be unacceptably hot and sooner or later lead to pump failure.

[0006] The problem underlying the present invention is that a hydraulic pump capable of producing a high pressure and never overheats at either a low rotational speed or a low capacity efficiency (a so-called hydraulic pump) (so-called). , Constant flow rate discharge hydraulic pump).

[0007]

To achieve the above object, a constant flow rate discharge hydraulic pump of the present invention has a housing characterized by a supply port for supplying a medium or a discharge port for discharging a medium. In a hydraulic pump for discharging a medium discharged by a pump at a constant flow rate,
The pump is characterized in that it further comprises an inlet / outlet for introducing or for delivering an additional medium flow, such as a cooling medium flow.

[0008]

The present invention is illustrated in the drawings using an internal gear pump. FIG. 1 shows a cross section perpendicular to the rotation axis of an internal gear pump according to the present invention. Inlet for introducing working medium 1.1
And the housing 1 with an outlet 1.2 for discharging the working medium is depicted in detail. In the housing 1, an external tooth pinion 2 and an internal gear 3 that additionally rotates together with the pinion are rotatably mounted.

A filling member is provided between the pinion 2 and the internal gear 3. The filling member is an inner piece 4.
1 and outer segment 4.2. As you can see
The outer segment is shaped like a relatively thin skin with a substantially constant wall thickness. The two sections 4.1 and 4.2 are separated from each other by a circumferentially extending gap 4.3. The two sections 4.1 and 4.2 are functionally supported on the stop pin 5. A constant medium pressure prevails in the pressure chamber 6 of the flow space of the machine. The pressure acts on the sections 4.1, 4.2 through the hole 3.1 in the internal gear 1. This pressure is due to the gap 4. between the sections 4.1, 4.2.
It also predominates in 3, resulting in the spread of two sections. That is, they are pressed so as to be radially separated from each other. The inner surface of the section 4.1 is pressed radially against the tips of the teeth of the pinion 2, and the outer surface of the section 4.2 is pressed radially against the tips of the teeth of the internal gear 3. This action provides a more or less good sealing of the pressure chamber 6 to the suction chamber 7.

2 to 7 show a slightly reduced scale of 3
1 shows the pump according to FIG. 1 in two different operating states, as well as an axial section (left view) and an axial vertical section (right view), respectively. 2 and 3 depict cooling oil being introduced into the pump.
This creates a cooling flow from the connection to the suction line.
4 and 5, the cooling oil is introduced into the pump,
It shows the heated oil being pumped out. Figures 6 and 7 show the heated oil being drawn from the pump and then the pump being replenished with fresh oil via the suction line.

The injection of fresh oil for cooling purposes is
You can do it anywhere. It is not always necessary to continuously supply the cooling oil to the pump. For example,
The cooling oil may be introduced intermittently. For example, a flow rate that varies over time but is controlled so that the pump is maintained at a preset maximum temperature, that is, the oil exiting the pump pressure chamber is maintained at a preset maximum temperature. The cooling oil may be introduced in. The problems of pumps that overheat under high pressure and low volumetric efficiency are solved in a surprisingly simple manner by the present invention.

[0012]

According to the present invention, a constant flow rate discharge hydraulic pump capable of generating high pressure by an extremely simple method and never overheated at any of low rotation speed and low capacity efficiency is provided. Can be realized.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a rotation shaft of an internal gear pump according to the present invention.

2 shows an internal gear pump according to the invention in relation to FIG. 1 in three different operating states, (a) showing cooling oil being introduced into the pump, FIG. Axial sectional view, (b) is an axial vertical sectional view thereof, (c) is an axial sectional view showing a state in which cooling oil is introduced into the pump and heated oil exits from the pump. ) Is the vertical cross section of the axis,
(E) is an axial sectional view showing a state in which heated oil is drawn out from a pump, and then the pump replenishes fresh oil via an intake line, and (f) is an axial vertical sectional view thereof. .

[Explanation of symbols]

 1 Housing 1.1 Inlet 1.2 Outlet 2 Pinion 3 Internal gear 3.1 Hole 4.1 Inner segment 4.2 Outer segment 4.3 Gap 5 Stoppin 6 Pressure chamber 7 Suction chamber

Claims (2)

[Claims] 1. A hydraulic pump for discharging a medium discharged by a pump at a constant flow rate, comprising a housing characterized by a supply port for supplying the medium or a discharge port for discharging the medium, A hydraulic pump, characterized in that the pump further comprises an inlet / outlet for introducing or discharging an additional medium flow such as a cooling medium flow. 2. An externally toothed pinion 2, an internal gear 3 that rotates together with the pinion 2, and a crescent-shaped filling member 4. that is arranged between the pinion 2 and the internal gear 3.
1, 4.2 and a stop pin 5 supporting the filling members 4.1, 4.2, in a hydraulic pump according to claim 1 in the form of an internal gear pump, wherein the pump is, for example, of cooling oil. For introducing or discharging an additional oil flow such as
The hydraulic pump according to claim 1, further comprising a doorway.