CN216198725U

CN216198725U - Duplex plunger pump

Info

Publication number: CN216198725U
Application number: CN202122530663.2U
Authority: CN
Inventors: 邹云璐
Original assignee: Bosch Rexroth Beijing Hydraulic Co Ltd
Current assignee: Bosch Rexroth Beijing Hydraulic Co Ltd
Priority date: 2021-10-20
Filing date: 2021-10-20
Publication date: 2022-04-05
Anticipated expiration: 2031-10-20

Abstract

A dual plunger pump comprising: an oil distribution ring; the first pump set and the second pump set are assembled on two sides of the oil distribution ring in the axial direction in an opposite mode, each of the first pump set and the second pump set is provided with a shell, a shaft carried by the shell and a cylinder body rotating along with the shaft, and the inner end of the shaft of the first pump set and the inner end of the shaft of the second pump set are connected through a spline sleeve, so that the cylinder bodies of the first pump set and the second pump set are staggered in a phase angle; a cylinder body of one of the first pump group and the second pump group is formed with a positioning hole at an outer periphery, and a housing of the one pump group is formed with a threaded hole adapted to be penetrated by a positioning pin at an axial position corresponding to the positioning hole; the periphery of the cylinder body of the other pump set is provided with a plurality of positioning grooves which are uniformly distributed along the circumferential direction, and the shell of the other pump set is provided with a threaded hole which is suitable for being penetrated by the positioning pin at the axial position corresponding to the positioning grooves. The dual plunger pump can be assembled in a low cost, simple assembly manner.

Description

Duplex plunger pump

Technical Field

The present application relates to a twin plunger pump having two plunger pump groups axially combined with each other.

Background

In the field of plunger-type hydraulic pumps, two axial plunger pumps are sometimes combined to form a dual plunger pump in order to increase the pump displacement. Dual piston pumps usually comprise two axially combined pump units, the cylinder of each pump unit being driven by a respective shaft. The two shafts are connected at their inner ends by a splined hub so that a common external drive source can drive both shafts simultaneously. Each cylinder contains a plurality of plungers, and the output pressure of each plunger is periodically changed (fluctuated). In order to avoid the overlarge output pressure fluctuation amplitude of the whole duplex plunger pump caused by the coincidence of the output pressure peak values of the two pump groups, the two pump groups are usually required to be staggered at an angle along the circumferential direction (circumferential direction for short) so that the output pressure peak of one pump group is coincided with the output pressure trough of the other pump group as much as possible. However, in order to allow optimum angular measures for both pump stacks, it is often necessary in the prior art to machine the spline housing and the splines at the inner end of the shaft with high precision or to require a complicated assembly process.

SUMMERY OF THE UTILITY MODEL

It is an object of the present application to provide a twin plunger pump that can be assembled in a low cost, easy to assemble manner.

To this end, the present application provides in one of its aspects a dual plunger pump comprising:

an oil distribution ring; and

the pump comprises a first pump set and a second pump set which are assembled on two sides of an oil distribution ring in the axial direction opposite to each other, wherein each of the first pump set and the second pump set is provided with a shell, a shaft carried by the shell and a cylinder body rotating along with the shaft, and the inner end of the shaft of the first pump set and the inner end of the shaft of the second pump set are connected through a spline sleeve, so that the cylinder bodies of the first pump set and the second pump set are staggered in a phase angle;

wherein the cylinder body of one of the first pump group and the second pump group is formed with a positioning hole at an outer periphery, and the housing of the one pump group is formed with a threaded hole adapted to be penetrated by a positioning pin at an axial position corresponding to the positioning hole; the periphery of the cylinder body of the other pump set is provided with a plurality of positioning grooves which are uniformly distributed along the circumferential direction, and the shell of the other pump set is provided with a threaded hole which is suitable for being penetrated by the positioning pin at the axial position corresponding to the positioning grooves.

In one embodiment, the locating hole is a single locating hole; or the positioning holes are a plurality of positioning holes uniformly distributed along the circumferential direction.

In one embodiment, the number of the positioning grooves is equal to the number of the plunger cavities in the cylinder body, or is an integral fraction of the plunger cavities in the cylinder body, or is an integral multiple of the plunger cavities in the cylinder body.

In one embodiment, each of the positioning grooves extends in a circumferential direction over an arc having an angle equal to more than one time an angle of a pitch of the spline housing teeth.

In one embodiment, the angle of the arc is smaller than the angle between adjacent plunger cavities in the cylinder.

In one embodiment, the shaft of the first pump group is driven to rotate by an external drive source, and the shaft of the second pump group is driven by the shaft of the first pump group through a spline sleeve; the locating hole is arranged on the cylinder body of the first pump group, and the locating groove is arranged on the cylinder body of the second pump group.

In one embodiment, the threaded holes of the first pump group and the threaded holes of the second pump group have the same circumferential position; and the angular position of the circumferential center of each positioning groove relative to the corresponding plunger cavity in the cylinder is equal to the angular position of the center of the positioning hole relative to the corresponding plunger cavity in the cylinder plus the phase angle.

In one embodiment, the threaded holes of the first pump group and the threaded holes of the second pump group are circumferentially offset by the phase angle; and the angular position of the circumferential center of each positioning groove relative to the corresponding plunger cavity in the cylinder is the same as the angular position of the center of the positioning hole relative to the corresponding plunger cavity in the cylinder.

In one embodiment, the threaded bores are each closed by a screw plug in the state in which the first pump stack and the second pump stack are assembled on the oil distribution ring.

In one embodiment, a plurality of weight-reducing grooves are formed on the outer circumference of the cylinder block of one or both of the first and second pump groups.

According to this application, be equipped with the locating hole on the cylinder body of pair plunger pump, be equipped with a plurality of constant head tanks on another cylinder body, this makes the equipment of two pump packages easier, has simplified assembly process, realizes the best angle that staggers more easily to need not with high accuracy processing spline, pair plunger pump's cost can reduce.

Drawings

The foregoing and other aspects of the present application will be more fully understood and appreciated by reference to the following detailed description, taken with reference to the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of a dual piston pump according to one possible embodiment of the present application;

FIG. 2 is a front view of a first cylinder in a dual ram pump;

FIG. 3 is a front view of a second cylinder in a dual ram pump;

FIG. 4 is an axial view of the second cylinder;

FIG. 5 is a schematic view of one possible embodiment of a locating pin used in the assembly of the dual plunger pump;

fig. 6 is a schematic illustration of the assembly process of the dual piston pump.

Detailed Description

The present application relates generally to a dual plunger pump, one embodiment of which is schematically illustrated in fig. 1. It should be noted that the structure of the dual piston pump is shown schematically, not to scale, and that certain elements and details have been omitted from the drawings in order to clearly illustrate the principles of the present application.

The double plunger pump includes a first pump group 1 and a second pump group 2 which are assembled to both axial sides of an oil distribution ring 3 in an axially opposed manner.

An oil inlet 4 and an oil outlet 5 are formed in the outer periphery of the oil distribution ring 3 for connection with an external pipeline. An oil inlet channel and an oil discharge channel are also formed in the oil distribution ring 3, and the oil inlet channel and the oil discharge channel are respectively communicated to the oil inlet 4 and the oil discharge port 5 on the one hand and to the two axial sides of the oil distribution ring 3 on the other hand. The oil distribution ring 3 is also internally provided with a through hole which is axially penetrated.

In addition, oil distribution rings 3 are provided with oil distribution discs 6, 7 on both axial sides thereof, respectively, each of which is formed with an oil inlet groove (a waist-shaped groove) communicating with an oil inlet passage of the oil distribution ring 3 and an oil discharge groove (a waist-shaped groove) communicating with an oil discharge passage of the oil distribution ring 3. The first pump set 1 and the second pump set 2 respectively suck hydraulic oil from an oil inlet 4 through an oil inlet groove of a corresponding oil distribution disc and an oil inlet channel in the oil distribution ring 3, and discharge pressurized hydraulic oil from an oil discharge port 5 through an oil discharge groove of the corresponding oil distribution disc and an oil discharge channel in the oil distribution ring 3.

The first pump group 1 comprises a casing 10 assembled on a first axial side of the oil distribution ring 3. An axially extending shaft 11 is carried by the housing 10, the outer end of the shaft 11 being exposed by the housing 10 for rotation by an external drive source, the main portion of the shaft 11 being located within the housing 10 and the inner portion of the shaft 11 extending into the through bore of the oil distribution ring 3. An outer portion of the shaft 11 is rotatably supported by an end wall of the housing 10, and an inner portion of the shaft 11 is rotatably supported by the oil distribution ring 3.

Inside the housing 10, a cylinder block 12 and a swash plate 13 are arranged. The cylinder 12 is mounted around the shaft 11 and rotates with the shaft 11. A swash plate 13 is fixed around the shaft 11 in the housing 10. The swash plate 13 may have a fixed angle of inclination relative to the shaft 11 so that the first pump group 1 has a constant displacement. Alternatively, the fixed inclination angle of the swash plate 13 relative to the shaft 11 is adjustable, for example by means of a variable head, so that the first pump group 1 has a variable displacement.

A plurality (typically an odd number) of axially extending plunger bores 14 are formed in the cylinder 12, each plunger bore 14 preferably being circumferentially equispaced. Each plunger chamber 14 is inserted with a plunger 15, the rear end of each plunger 15 is connected with a corresponding slipper 16, and each slipper 17 can push against the swash plate 13 in a sliding manner.

On the other hand, the second pump group 2 includes a housing 20 assembled to the second side in the axial direction of the oil distribution ring 3, and a shaft 21, a cylinder block 22 (formed with plunger chambers 24 in the same number as the plunger chambers 14), a swash plate 23, plungers 25, and shoes 26 arranged in the housing 20. The shaft 21 is coaxial with the shaft 11, an outer end of the shaft 21 is rotatably supported by an end wall of the housing 20, and an inner portion of the shaft 21 is rotatably supported by the oil distribution ring 3. The structures of the cylinder block 22 (including the plunger chamber 24), the swash plate 23, the plungers 25, and the shoes 26 are the same as or similar to the corresponding elements in the first pump unit 1 described above, and will not be described here.

The inner ends of the

shafts

11, 21 form splined shaft ends 17, 27, respectively. The splined shaft ends 17, 27 are inserted axially opposite each other into the splined hub 30. The spline housing 30 is rotatably disposed in the through hole of the oil distribution ring 3. The

shafts

11, 21 are coupled by the spline housing 30. When the shaft 11 is driven to rotate, the shaft 21 is driven to rotate synchronously by the spline housing 30. The

cylinders

12, 22 rotate with the

shafts

11, 21, respectively. Since the

shoes

16, 26 slide on the fixed

swash plates

13, 23 respectively to cyclically change the axial positions, the

shoes

16, 26 drive the

corresponding plungers

15, 25 to reciprocate in the

corresponding plunger chambers

14, 24 to draw oil from the oil inlet 4 and discharge oil from the oil discharge port 5.

For each

plunger

15, 25, it completes one oil suction and oil discharge cycle as the

shaft

11, 21 rotates one revolution. The oil discharge pressure of the

plungers

15, 25 fluctuates in each cycle. In order to reduce the amplitude of the pressure fluctuation of the oil discharge of the entire double piston pump, the cylinder block 22 is shifted by a phase angle (circumferential angle) θ in the rotational direction with respect to the cylinder block 12 so that the pistons 15 in the cylinder block 12 and the pistons 25 in the cylinder block 22 are circumferentially shifted from each other. The phase angle is chosen such that the pressure peaks and troughs of the output oil pressure of the first pump group 1 are as close as possible to the pressure troughs and peaks, respectively, of the output oil pressure of the second pump group 2.

To achieve the above-described phase angle difference in the assembled tandem plunger pump, the present application forms locating holes 18 in the outer periphery of cylinder 12 and a circle of discrete detents 28 in the outer periphery of cylinder 22. Further, one screw hole 19 is formed at an axial position of the housing 10 corresponding to the positioning hole 18, and one screw hole 29 is formed at an axial position of the housing 20 corresponding to the positioning groove 28, as shown in fig. 1. The threaded holes 19, 29 preferably have the same diameter and thread gauge.

Referring to FIG. 2, the pilot bore 18 extends radially inward from the outer peripheral surface of the cylinder block 12 to form a blind bore.

Circumferentially, the positioning hole 18 may be located between two adjacent plunger bores 14, e.g. exactly in the middle. The diameter of the positioning hole 18 is smaller than the diameter of the threaded hole 19.

For the assembly process, it suffices to form one positioning hole 18 on the outer periphery of the cylinder block 12. However, in consideration of the dynamic balance problem when the cylinder block 12 rotates, a plurality of positioning holes 18 may be formed on the outer periphery of the cylinder block 12, which are evenly distributed in the circumferential direction, and the number of the positioning holes 18 may be equal to the number of the plunger chambers 14, or an integer fraction of the number of the plunger chambers 14 (if the number of the plunger chambers 14 can be evenly divided).

Referring to fig. 3 and 4, a plurality of positioning grooves 28 are formed on the outer circumference of the cylinder 22 to be uniformly distributed in the circumferential direction. The number of detents 28 may be equal to the number of plunger bores 24, or an integer fraction of the number of plunger bores 24 (if the number of plunger bores 24 is divisible), or an integer multiple of the number of plunger bores 24. Further, although in the example shown in the drawings, positioning grooves 28 are formed over the outer periphery of cylinder 22 by one full turn, this is not necessary and it may not be formed over the entire turn. Furthermore, it is preferable that each detent 28 is evenly distributed on the outer periphery of the cylinder 22 (to facilitate dynamic balance), but the scope of the present application also encompasses arrangements in which each detent 28 is not evenly distributed.

In the present application, the term "plurality" means two or more.

Each detent groove 28 extends radially inward a distance from the outer peripheral surface of the cylinder 22 (e.g., equal to or similar to the radial extension of the detent hole 18), and extends circumferentially at an arc angle. The arc angle may be set equal to more than one time, for example 1.5 to 3 times, the pitch (in degrees) of the splines on the spline shaft end 27. The arc angle is less than the angle between adjacent plunger bores 24.

The circumferential center of each detent 28 may be, but need not be, located between two adjacent plunger bores 14, such as exactly midway therebetween. The arc of circumferential extension of each detent 28 is less than the angle between two adjacent plug cavities 24. The width of each detent 28 is less than the diameter of threaded bore 29 and may be approximately equal to the diameter of detent hole 18.

In order to shift the phase angle in the rotational direction of the assembled cylinder block 22 relative to the cylinder block 12, the circumferential positional relationship of the threaded

holes

19, 29 and the circumferential positional relationship of the positioning hole 18 and the positioning groove 28 are cooperatively considered.

For example, the threaded

holes

19, 29 may be arranged to have the same circumferential position. In this case, assuming that the center line of the positioning hole 18 lags behind the center line of the plunger cavity 14 adjacent to the front side in the rotational direction by an angle α, the circumferential center line of each positioning groove 28 lags behind the center line of the plunger cavity 24 adjacent to the front side in the rotational direction by an angle β, β ═ α + θ.

For another example, the circumferential position of the threaded hole 29 may be retarded by the phase angle with respect to the rotational direction with respect to the circumferential position of the threaded hole 19. In this case, assuming that the center line of the positioning hole 18 lags behind the center line of the rotationally adjacent plunger cavity 14 by an angle α with respect to the front side in the rotational direction, the circumferential center line of each positioning groove 28 also lags behind the center line of the rotationally adjacent plunger cavity 24 by the angle α.

Other solutions are conceivable in respect of the above-mentioned co-operation to ensure that the phase angle deviation is formed.

Two locating pins are required for assembly. The positioning pins can be inserted through the threaded

holes

19, 29 into the positioning holes 18 and the positioning grooves 28.

One example of a locating pin is a straight pin.

Another example of a locating pin is seen in fig. 5. Referring to fig. 5, this form of locating pin 32 includes a handle 33, a threaded portion 34 extending forwardly from the handle 33 (arranged to engage the threaded bores 19, 29), and a pin portion 35 projecting forwardly of the threaded portion 34. The diameter of the pin portion 35 at least at its distal end is slightly smaller than the diameter of the positioning hole 18 and the width of the positioning groove 28 so that the distal end of the pin portion 35 can be inserted into the positioning hole 18 and the positioning groove 28.

The assembly process of the twin piston pump is generally as shown in figure 6. The second pump stack 2 is first assembled with a locating pin 32 inserted through the threaded bore 29 into the housing 20, the end of the pin 35 inserted into a locating slot 28 and the threaded portion 34 engaged with the threaded bore 29. Detent 28 is not locked at the end of pin 35, but rather allows cylinder 22 to rotate about shaft 21 through an angular range defined by the location where the ends of detent 28 contact the end of pin 35. Further, a spline housing 30 is fitted over the spline shaft end 27.

Next, the second pump group 2 is assembled to the oil distribution ring 3 with the spline housing 30 in the correct position in the rotational direction. At this time, the spline housing 30 is located in the through hole of the oil distribution ring 3.

Next, the first pump stack 1 is assembled, wherein the other positioning pin 32 is inserted into the casing 10 through the threaded hole 19, the pin portion 35 ends are inserted into the positioning hole 18, and the threaded portion 34 engages with the threaded hole 29. Due to the restraining action of the pin 35, the cylinder 12 is substantially prevented from rotating about the shaft 11.

Next, the first pump stack 1 is assembled to the oil distribution ring 3 with the splined shaft end 17 inserted facing the splined sleeve 30. The present application allows for the use of splines of lower precision, whereby it is possible that the splined shaft end 17 may not be inserted into the splined hub 30 immediately, but that the splined shaft end 17 needs to be tentatively inserted into the splined hub 30 by turning the first pump stack 1, after inserting the splined shaft end 17 into the splined hub 30, it is possible that the first pump stack 1 is rotationally out of the expected correct assembly position by a small angle. In this case, the first pump group 1 is rotated to the correct assembly position. On the other side, the cooperating relationship of the positioning slot 28 with the positioning pin 32 allows such a rotation of the first pump group 1. Then, the first pump group 1 is assembled on the oil distribution ring 3.

After the first pump group 1 and the second pump group 2 are assembled to the oil distribution ring 3, the two positioning pins 32 are removed, and then the threaded

holes

19 and 29 are closed by the screw plugs 31 shown in fig. 1. In this way, an assembled double piston pump is obtained.

It will be appreciated that a plurality of alignment slots 28 may be provided in cylinder 12 and one or more alignment slots 18 may be provided in cylinder 22, again to accomplish similar assembly-assist functions.

In addition, providing a plurality of detents 28 on the cylinder 22 also enables a reduction in weight of the cylinder 22.

To reduce the weight of the cylinder block 12, a plurality of weight-reducing grooves 36 may be formed on the outer periphery of the cylinder block 12 at axial positions different from the positioning holes 18, see fig. 2. The form of the weight-reducing recess 36 on the cylinder 12 may be similar to, the same as, or different from the detent 28 on the cylinder 22. The lightening recesses 36 are distributed (preferably evenly distributed) in the circumferential direction. Only one turn of the weight-reducing grooves 36 may be provided, or a plurality of turns of the weight-reducing grooves 36 may be provided at different axial positions.

To further reduce weight of cylinder 22, a plurality of weight-reducing recesses (see weight-reducing recesses 36 described above) may also be formed in the outer periphery of cylinder 22 at different axial locations than detents 28, and may be of similar, identical or different form than detents 28.

Furthermore, the weight-reducing grooves on the cylinder block 12 and/or the cylinder block 22 may, but need not, be full on the outer circumference of the cylinder block. In addition, it is preferable that the weight-reduction grooves are uniformly distributed on the outer periphery of the cylinder block (in favor of dynamic balance), but the scope of the present application also includes a scheme in which the weight-reduction grooves are not uniformly distributed.

According to this application, be equipped with the locating hole on the cylinder body of pair plunger pump, be equipped with a plurality of constant head tanks on another cylinder body, this makes the equipment of two pump packages easier, has simplified assembly process to need not be with high accuracy processing spline, pair plunger pump's cost can reduce.

In addition, a plurality of positioning grooves are uniformly distributed along the axial direction, the extension length of each positioning groove can be smaller, the relative positioning precision of the two pump sets can be improved, and the combination of the optimal staggered angle can be realized more easily.

Although the present application has been described herein with reference to particular embodiments, the scope of the present application is not intended to be limited to the details shown. Various modifications may be made to these details without departing from the underlying principles of the application.

Claims

1. A dual plunger pump comprising:

an oil distribution ring (3); and

a first pump group (1) and a second pump group (2) assembled opposite to each other on both sides of an oil distribution ring (3) in the axial direction, each of the first pump group and the second pump group having a housing, a shaft carried by the housing, and a cylinder block rotating with the shaft, wherein an inner end of the shaft of the first pump group and an inner end of the shaft of the second pump group are connected by a spline housing (30) so that the cylinder blocks of the first pump group and the second pump group are staggered by a phase angle;

characterized in that the cylinder block of one of the first and second pump groups is formed at the outer periphery with a positioning hole (18), and the housing of said one pump group is formed at an axial position corresponding to the positioning hole with a threaded hole adapted to be passed through by a positioning pin; the periphery of the cylinder of the other pump group is formed with a plurality of positioning grooves (28) uniformly distributed along the circumferential direction, and the shell of the other pump group is formed with threaded holes suitable for being penetrated by the positioning pins at the axial positions corresponding to the positioning grooves.

2. The dual plunger pump of claim 1 wherein said alignment aperture is a single alignment aperture; or the positioning holes are a plurality of positioning holes uniformly distributed along the circumferential direction.

3. The tandem plunger pump of claim 1, wherein the number of positioning slots is equal to the number of plunger cavities in the cylinder, or is an integral fraction of the plunger cavities in the cylinder, or is an integral multiple of the plunger cavities in the cylinder.

4. The dual plunger pump of claim 1 wherein each detent groove extends circumferentially over an arc equal to more than one time the angle of the spline housing between the teeth.

5. The twin piston pump defined in claim 4, wherein the arc has an angle less than the angle between adjacent piston chambers in the cylinder.

6. The tandem plunger pump of claim 1, wherein the shaft of the first pump group is driven to rotate by an external drive source, and the shaft of the second pump group is driven by the shaft of the first pump group through a spline housing; the locating hole is arranged on the cylinder body of the first pump group, and the locating groove is arranged on the cylinder body of the second pump group.

7. The tandem plunger pump according to any one of claims 1 to 6, wherein the screw hole of the first pump group and the screw hole of the second pump group have the same circumferential direction position; and is

The angular position of the circumferential center of each positioning slot relative to the corresponding plunger cavity in the cylinder is equal to the angular position of the center of the positioning hole relative to the corresponding plunger cavity in the cylinder plus the phase angle.

8. The tandem plunger pump according to any one of claims 1 to 6, wherein the threaded holes of the first pump group and the threaded holes of the second pump group are circumferentially staggered by the phase angle; and is

The angular position of the circumferential center of each positioning groove relative to the corresponding plunger cavity in the cylinder is the same as the angular position of the center of the positioning hole relative to the corresponding plunger cavity in the cylinder.

9. The double piston pump as claimed in one of claims 1 to 6, characterized in that the threaded bores are each closed by a screw plug (31) in the state in which the first pump group and the second pump group are assembled on the oil distribution ring.

10. The tandem plunger pump according to any one of claims 1 to 6, wherein a plurality of weight-reduction grooves are formed on the outer circumference of the cylinder block of one or both of the first pump group and the second pump group.