UA75722C2 - Dosing pump (variants) - Google Patents

Abstract

Dosing pump contains distribution unit coaxial to two dosing sections, each of which consists of stator with internal gears, and the rotor engaged with them by external gears. The rotor of the first section is connected with the distribution unit by cardan shaft. The rotors of both sections are connected by coupling link. For simplification of the design the coupling link and the device of change of summary capacity are executed in the form of built-up shaft having two parts. These parts are connected with appropriate rotors and are installed on the common cylindrical rotational axle and are fixed in the neutral position relative to each other with the help of the torsion spring. At the joint of parts there are end projections located in the spaces between similar projections of another part of the shaft with bilateral angular clearance.

Description

Description of the invention

The invention relates to the field of machine-building hydraulics and can be used in hydraulic drives 9 with metered supply of working fluid under pressure to executive bodies, for example, to hydraulic cylinders of stationary equipment or steering mechanisms of agricultural, construction, road and other self-propelled machines.

There are well-known metering pumps designed to regulate the flow of working fluid entering the executive hydraulic cylinders depending on the angle of rotation of the metering pump shaft, and the volume of supplied liquid per 70 revolutions of the drive shaft (working volume) depends on the operating mode of the hydraulic drive.

Basically, in the regular mode of operation, when the working fluid is supplied to the metering pump from the drive pump, the amount of its working volume is selected according to the diameter of the executive hydraulic cylinders and the given movement of the rod per one revolution of the metering pump shaft at the nominal mode of operation of the hydraulic drive. In case of stopping the supply of working fluid under pressure to the dosing pump due to, for example, the failure of the drive pump 72, rupture of the pressure hose and other reasons, it switches to the emergency, pumping mode of operation. At the same time, there is an automatic reduction of its working volume to a value that provides the possibility of its manual drive without excessive muscular efforts of the operator. Usually this volume is equal to 160...200 cmU/rev.

Thus, the dosing pumps described in patents PCT UUO 96/30248 kl. MKV" е15В8 13/10, 1998 and UMO 97/30881 kl.

MKV'/ g16O 31/02, 2000), contain two dosing sections, and the working volume of one of the sections is no more than the volume that provides the possibility of manual drive of the dosing pump in pump mode, and a device for changing its total supply, which is a spool located in the bore of the housing, which is under the action of a spring and depending on the position of which there is either a summation of the liquid flows passing through c both sections in the presence of pressure at the inlet to the dosing pump, and then its working volume will correspond to the nominal mode of operation of the hydraulic drive, or in the absence of pressure at the inlet, the working fluid enters only through one, the above-mentioned section, while the other section works at idle.

The disadvantage of these dosing pumps is a significant complication of the design due to the introduction of a precise spool pair and a number of additional channels and holes, including deep drilling. с зо The closest analog of the dosing pump that is claimed, and chosen as a prototype, is the hydraulic steering mechanism of the vehicle, described in |

This steering mechanism contains a distribution unit coaxial with the two dosing sections. Each of the sections consists of a stator with internal teeth and a rotor engaged with them by external teeth. The rotor of the first section is connected to the distribution block by a cardan shaft, and the rotors of both sections are connected to each other by a connecting o

Зз5 link. A device for changing the total feed of the dispenser is located between the dosing sections. Cha

In the same way as in previous analogues, the functions of the device for changing the total feed in this design are performed by the spool, which is under the action of a spring.

The presence in this device of a precise spool pair and additional channels and holes, including deep drilling, determines the complexity of the design of the dosing pump. "

In addition, in the transitional mode of its operation with reduced pressure at the inlet, due to a partial drop of 8 s in the characteristics of the drive pump, as a result of the wear of its parts, the spool can be in some intermediate position, connecting all the working chambers with each other, or, depending on the ratio "» of real linear dimensions in the spool pair will block the working chambers of the second dosing section. In both cases, this will lead to a short-term and repeated failure of the steering.

The basis of the invention is the task of simplifying the design and ensuring reliable operation of the dosing pump in transient mode.

This problem is solved by the fact that in a known dosing pump, which contains a distribution unit coaxial with two and dosing sections, each of which consists of a stator with internal teeth and a rotor engaged with them by external teeth, the rotor of the first section is connected to the distribution block is a cardan shaft, the rotors of both sections are connected to each other by a connecting link, and the device for changing the total supply is located between the dosing sections, according to the invention, the connecting link and the device for changing the total supply are made in the form of a folded shaft,

Kz that has two parts that are connected to the corresponding rotors mounted on a common cylindrical axis and fixed in a neutral position relative to each other by means of a torsion spring, and at the junction between them have end protrusions located in the gaps between similar protrusions of the other part of the shaft with a DdVOStTOoron angular gap equal to 1802/27, where 7 is the number of rotor teeth.

In another version of the construction of the composite shaft, the parts of the shaft connected to the rotors are fixed in i) a neutral position relative to each other by means of an intermediate sleeve having end protrusions, which are located with one-sided angular clearances equal to 1802/7, in the spaces between similar protrusions of parts of the shaft, and two torsion springs installed with a previous torque, each of which one end 60 is clamped in an intermediate sleeve, and the other - in the corresponding part of the folded shaft.

Due to this design of the connecting link in the form of a folded shaft, when the metering pump is switched to manual operation mode, one rotor is automatically turned relative to the other at a given angle due to the presence of a pressure drop of the working fluid injected by the metering pump, and the installation, thus , working chambers of the second dosing section in antiphase with respect to the working chambers of the first section. As a result, unlike the 65 prototype, the performance of the section with a smaller working volume is subtracted from the performance of the section with a larger working volume. At the same time, the total supply of the dosing pump will be the required supply for its operation in manual mode.

This design and the second version of the shaft design, which combines the functions of the connecting link and the device for changing the total supply, makes it possible to exclude from the metering pump a spool pair between sections and a system of channels and holes that perform the functions of switching fluid flows when changing the mode of operation of the metering pump and , thus, to significantly simplify the design of the dosing pump and reduce the complexity of its manufacture. In addition, such a design, as shown below, ensures stable operation of the dosing pump in transient mode.

The following is a description of the invention, explained by an example of its specific implementation and drawings, where: 70 fig. 1 - depicts a longitudinal section of the metering pump in normal operation mode; fig. 2 - depicts part of the longitudinal section of the dispenser pump, which is turned relative to the section shown in Fig. 1, when working in manual pumping mode; fig. C - depicts a cross section along A-A, which shows the location of the stator and rotor of the first section; fig. 4 - depicts a cross-section along B-B, which shows the location of the stator and rotor of the second section /5 of the metering pump relative to the first section during its operation in pumping mode;

Fig. 5 - depicts in an enlarged view a separate section of the folded shaft connecting the dosing sections, with its parts fixed in the neutral position by the torsion spring; fig. 6 - depicts a section of the shaft along B-B, which shows the position of the protrusions of its parts during normal operation; fig. 7 - shows the section shown in fig. 6, on which the protrusions of the shaft parts are located in the pumping mode of operation; fig. 8 - depicts in an enlarged view separately another version of the design of the folded shaft connecting the dosing sections, with its parts fixed in the neutral position by an intermediate sleeve and two torsion springs; with fig. 9 - depicts a section of the shaft variant along GG, which shows the position of the protrusions of its parts during normal operation; i) fig. 10 - shows the section shown in fig. 9, on which the protrusions of the shaft parts are located in the pumping mode of operation;

The dosing pump contains a distribution block 1 with an input shaft 2 and a spool with two coaxial dosing sections. Each of the sections, respectively, consists of stators 4 and 5 with internal teeth and external teeth of rotors b and 7 engaged with them, see Fig. fig. 1 and 2. Stator teeth 4 and 5 and, respectively, rotor teeth 6 and 7 c form working chambers 8 and 9 isolated from each other, the total number of which in each of the sections is equal to M number of stator teeth, see fig. With and 4.

The values of the working volumes of the sections are selected in such a way that their sum meets the requirements for operation of the dosing pump in the dosing mode for a specific hydraulic drive, and the difference is not greater than the volume that provides the possibility of manual operation of the dosing pump in the pump mode.

Rotors 6 and 7 sections are connected to each other by a shaft 10 consisting of two parts 11 and 12 with splined toothed crowns 13 and 14 at the ends, which are included in the corresponding splined holes of rotors b and 7 with the possibility of some misalignment during rotation transmission. In addition, the rotor 6 of the first section is connected to the spool with cardan shaft 15, see fig. 71 and 5. with c Two parts 11 and 12 of the folded shaft 10 are mounted on a common cylindrical axis 16 and interact with each other with the help of end protrusions 17 and 18. In the neutral position, parts 11 and 12 are fixed by a spring;" twisting 19 in such a way that in the absence of a twisting moment on the shaft, there will be angular gaps 20 and 21 between the protrusions 17 and 18. These gaps allow the relative rotation of parts 11 and 12 in one direction or another by an angle a equal to 1802/7, where 7 - the number of teeth in the rotors, see fig. 6 and 7. -and In another version of the shaft design, between the parts 11 and 12 of the shaft 10, there is an intermediate sleeve 22, which has end protrusions 23 at both ends, interacting with similar protrusions 24 of these parts. The neutral and relative position of parts 11 and 12 is supported by pre-twisted springs 25 and 26, see fig. 8. They, respectively, connect parts 11 and 12 of the shaft 10 with the intermediate bushing 22. Between the end projections 23 of the bushing 22 and the 5r projections 24 of the parts of the shaft 10, there are only one-sided angular clearances 27. As a result, the relative rotation of the parts of the shaft at an angle and it is possible in one direction due to the corner clearances 27 on one side of the intermediate sleeve 22, and due to the clearances between the protrusions on the other side of the sleeve, - turning to the other side, see fig. 9 and 10. This design of the folded shaft ensures a more accurate and stable fixation of the neutral relative position of its parts.

In the intermediate body part 28, a number of axial holes 29 are made, the number of which is equal to the number of stator teeth, that is, the number of working chambers, for hydraulically connecting the dosing sections to each other and which are (F, extensions of the supply channels 30 in the distribution block 1, see Fig. 3 . km The dosing pump works in the following way.

When the drive pump is working properly and the input shaft 2 is stationary, the working fluid entering the inlet of the metering pump passes further through the system of channels in the distribution block 1 (not shown in the drawings) and, bypassing the metering sections 4 and 5, as in the known conventional dosing pumps, drains into the tank.

When the input shaft 2 is turned in one direction or another, the channels in the distribution block, which previously connected the pressure hydraulic line with the drain, overlap. The working fluid through part of the ZO channels under pressure enters the working chambers 8 of sections 4 and 5, which expand, for example, for the direction of rotation shown in fig. From and from the 65 narrowing chambers 9, the working fluid is pushed through the remaining channels 30 into the control main and, further, to the executive body, for example, to the hydraulic cylinder (not shown in the drawings). At the same time, the rotors perform a complex planetary rotation, and the distribution of the working fluid is carried out by the spool 3, which is driven into rotation by the rotor of section 4 through the cardan shaft 15. At the same time, the shaft 10 connecting the rotors of sections 4 and 5 does not transmit torque, and , so the operation of the sections coincides in phase, and the axis of the shaft 10 remains parallel to the general axis of the dosing pump. The working volume of the dosing pump in this mode is equal to the sum of the working volumes of the dosing sections and meets the requirements of the nominal operating mode of the hydraulic drive.

In case of stopping the supply of working fluid to the dosing pump under pressure due to, for example, the failure of the drive pump, rupture of the pressure hose, etc., the dosing pump automatically switches to the emergency, pumping mode of operation. At the same time, the working fluid is sucked from the supply line and pumped under 7/0 pressure to the executive body, which, in turn, leads to a significant increase in both the torque required for the manual drive of the metering pump as a whole, and that it is important that the moment on the shaft 10, which rotates the rotor 7 of the second section and which at the same time becomes greater than the moment of twisting the springs 19, 25 or 26 by the angle "7.

The torque from the input shaft 2 in this mode is transmitted through the cardan shaft 15 of the rotor of the dosing section 4 and, further, through the shaft 10 of the rotor of the dosing section 5. Due to the presence of the torque on the shaft 10 of it /5 parts 11 and 12 with toothed crowns 13 and 14 are rotated relative to each other to the mutual abutment of protrusions 17 and 18 by an angle equal to half the angular step of the toothed crown of the rotor, in this example of the implementation of the invention at 302 for 2-6.

As a result, dosing sections 4 and 5 are in antiphase, i.e. working chambers 8 of section 4, which are expanding at the moment, through part of the holes 29 and channels ZO are connected to the chambers 31 of section 5, which are reduced in volume, and the chambers 32, which are expanding, are connected to the narrowing chambers 9 of section 4.

As a result, the volume of the working chambers of section 5 is calculated from the volume of the chambers of section 4, and the resulting misalignment of the rotors 6 and 7 is compensated for by some misalignment of the shaft 10.

In the version of the design of the shaft 10 with an intermediate sleeve 22, the relative rotation of its parts, in one direction or another, already occurs due to the angular clearances between the protrusions of the sleeve 22 and the corresponding parts of the shaft from different ends of the sleeve 22 with the same result.

At the same time, the working volume of the dosing pump becomes equal to the difference between the working volumes of the dosing sections 4 and 5, such that it is possible to manually drive the dosing pump in pump mode without significant muscular effort by the operator.

Such a design of the folded shaft connecting the dosing sections will allow combining the functions of the connecting link and the device for changing the total supply and, thus, to significantly simplify the design of the dosing pump and reduce the complexity of its manufacture. high school

With reduced pressure at the inlet to the metering pump, for example, in the case of a partial drop in the characteristics of the drive pump due to wear of its parts, a transient mode may occur in its operation with incomplete mutual rotation of the shaft parts within the angle a. In this case, the total working volume o of the dosing pump takes some intermediate value between the maximum and minimum, and the lack of power developed by the pump is compensated by the efforts of the operator (driver), which ensures stable operation of the dosing pump in transient mode "Yu

Claims (1)

The formula of the invention C p 1. A dosing pump containing a distribution block, coaxial with two dosing sections, each of which "z" consists of a stator with internal teeth and a rotor engaged with them by external teeth, the rotor of the first section is connected to the distribution block by a cardan shaft, the rotors of both sections are connected to each other by a connecting link, and there is also a device for changing the total feed located between the dosing sections, which differs in that the connecting link and the device for changing the total feed are made in the form of a folded shaft, which has the two parts, which are connected to the respective rotors, are mounted on a common cylindrical axis of rotation and are fixed in a neutral position relative to each other by means of a torsion spring, and at the junction between - and themselves have end protrusions located in the spaces between similar protrusions of the other part a shaft with a two-sided angular clearance equal to 1802/7, where 7 is the number of rotor teeth. o 2. A dosing pump containing a distribution block, coaxial with two dosing sections, each of which ГЯ6) consists of a stator with internal teeth and a rotor engaged with them by external teeth, the rotor of the first section is connected to the distribution block by a cardan shaft, between each other the rotors of both sections are connected by a connecting link, and there is also a device for changing the total feed located between the dosing sections, which differs in that the connecting link and the device for changing the total feed are made in the form of a folded shaft, which has two parts that connected to the respective rotors, mounted on a common cylindrical axis of rotation and Ф) fixed in a neutral position relative to each other by means of an intermediate sleeve placed between the parts of the compound shaft, having end protrusions, which are located with one-sided angular clearances equal to 1802/ 2 (where 7 is the number of rotor teeth), in the spaces between similar protrusions of the parts of the folded shaft and two torsion springs, install enims with a previous tightening torque, each of which is clamped at one end in an intermediate sleeve, and at the other - in the corresponding part of the folded shaft. b5