CN220622163U - Composite pump - Google Patents

Abstract

The present disclosure relates to a compound pump, which comprises a first pump body, a second pump body and a transmission matching structure, wherein a first pump shaft is arranged in the first pump body, a second pump shaft is arranged in the second pump body, and the first pump shaft and the second pump shaft are coaxially arranged; a first external spline structure is arranged at one end of the first pump shaft, which is close to the second pump shaft, and a second external spline structure is arranged at one end of the second pump shaft, which is close to the first pump shaft; the transmission matching structure comprises a spline sleeve, the spline sleeve is sleeved at one end of the first pump shaft and one end of the second pump shaft, which are close to each other, and the first external spline structure and the second external spline structure are matched and connected with the internal spline structure of the spline sleeve. The spline housing is used as a transmission matching structure, and can be matched and connected with the first external spline structure and the second external spline structure through the internal spline structure of the spline housing, so that the transmission matching of the first pump body and the second pump body is realized, and the service life, the transmission stability and the reliability of the compound pump are improved.

Description

Composite pump

Technical Field

The present disclosure relates to the field of automotive engines, and in particular to a compound pump.

Background

In recent years, with the rapid development of the automobile manufacturing industry, a composite pump formed by integrating a plurality of pump bodies with different functions has been widely applied to a steering system or a braking system of an automobile, and the composite pump can reduce the manufacturing cost of the pump body and save the space occupied by the pump body. In compound pumps, it is often necessary to provide a drive structure to achieve a drive fit between the individual pump bodies in the compound pump.

However, the transmission mode of the pump body in the existing compound pump causes the compound pump to have the problems of short service life, poor transmission stability and reliability and the like, and the hidden trouble of product failure and fault is large.

Disclosure of Invention

In order to overcome the problems in the related art, the present disclosure provides a compound pump to solve the technical problems of short service life, poor transmission stability and reliability.

According to some embodiments of the present disclosure, there is provided a compound pump including a first pump body, a second pump body, and a drive fit structure, a first pump shaft disposed within the first pump body, a second pump shaft disposed within the second pump body, the first pump shaft disposed coaxially with the second pump shaft; a first external spline structure is arranged at one end, close to the second pump shaft, of the first pump shaft, and a second external spline structure is arranged at one end, close to the first pump shaft, of the second pump shaft; the transmission matching structure comprises a spline sleeve, the spline sleeve is sleeved at one end of the first pump shaft and one end of the second pump shaft, which are close to each other, and the first external spline structure and the second external spline structure are matched and connected with the internal spline structure of the spline sleeve.

In some embodiments of the present disclosure, a groove is disposed on an inner circumference of the spline housing, the groove is disposed between one ends of the first pump shaft and the second pump shaft, the transmission matching structure further includes a steel wire check ring, a part of the steel wire check ring is embedded in the groove, and another part of the steel wire check ring is located outside the groove.

In some embodiments of the present disclosure, the drive mating structure further includes a needle bearing sleeved on an outer circumference of the spline housing.

In some embodiments of the disclosure, a cavity structure is disposed in the first pump body, the transmission matching structure is disposed in the cavity structure, a shaft hole is disposed at one end of the first pump body, which is close to the second pump body, and one end of the second pump shaft, which is close to the first pump shaft, enters the cavity structure through the shaft hole.

In some embodiments of the present disclosure, the number of teeth of the first external spline structure, the second external spline structure, and the internal spline structure is 24, and the moduli of the first external spline structure, the second external spline structure, and the internal spline structure are all 0.5mm.

In some embodiments of the present disclosure, the first external spline structure, the second external spline structure, and the internal spline structure are involute splines.

In some embodiments of the present disclosure, the spline housing comprises 42 chromium molybdenum.

In some embodiments of the present disclosure, the first and second external spline structures are clearance fit with the internal spline structure.

In some embodiments of the disclosure, the first pump body is a steering vane pump and the second pump body is a hydraulic brake gear pump.

In some embodiments of the disclosure, the first pump body and the second pump body are correspondingly provided with mutually communicated bolt holes, and the first pump body and the second pump body are fastened and connected through bolts penetrating through the bolt holes.

The compound pump provided by the embodiment of the disclosure has at least the following beneficial effects: be provided with coaxial first pump shaft and second pump shaft respectively in the first pump body and the second pump body, and be provided with first external spline structure and second external spline structure respectively on first pump shaft and the second pump shaft, regard as the transmission cooperation structure with the spline housing, can be connected with first external spline structure and the cooperation of second external spline structure through the internal spline structure of spline housing, realize the transmission cooperation of first pump body and second pump body, promoted compound pump's life, transmission stability and reliability.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the embodiments of the disclosure. In the drawings, like reference numerals are used to identify like elements. The drawings, which are included in the description, are some, but not all embodiments of the disclosure. Other figures can be obtained from these figures without inventive effort for a person skilled in the art.

Fig. 1 is a cross-sectional view of a compound pump along an axial direction, according to an example embodiment.

Fig. 2 is a partial enlarged view at a in fig. 1, shown according to an exemplary embodiment.

FIG. 3 is a schematic diagram of a compound pump, according to an example embodiment.

In the figure:

10-a first pump body; 11-a first pump shaft; 12-a first external spline structure; 20-a second pump body; 21-a second pump shaft; 22-a second external spline structure; 30-a transmission matching structure; 40-spline housing; 41-an internal spline structure; 50-a steel wire retainer ring; 51-groove; 60-needle bearings; 61-rolling pins; 70-cavity structure; 80-shaft holes; 90-bolt holes.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples are not representative of all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present disclosure as detailed in the accompanying claims.

With the high-speed development of the automobile manufacturing industry, in order to reduce the manufacturing cost and the occupied space of a plurality of pump bodies with different functions, a composite pump structure formed by integrating the pump bodies with different functions is widely applied to systems such as automobile steering, braking and the like. In order to meet the synchronous operation condition of multiple pump bodies in a compound pump, a transmission structure is generally required to be arranged in the compound pump so as to enable each pump body to be in series transmission.

However, in the related art, a transmission mode of connecting blocks or concave-convex keys is adopted between pump bodies with different functions in the compound pump, so that transmission structures such as the connecting blocks or the concave-convex keys are seriously worn in the use process, faults such as transmission failure and the like can be generated, and the service life of the compound pump and the transmission stability and reliability among different pump bodies in the compound pump are seriously affected.

Based on this, this disclosed exemplary embodiment provides a compound pump, be provided with coaxial first pump shaft and second pump shaft respectively in first pump body and the second pump body, and be provided with first external spline structure and second external spline structure on first pump shaft and the second pump shaft respectively, regard as the transmission cooperation structure with the spline housing, can be through the internal spline structure and first external spline structure and the cooperation of second external spline structure of spline housing be connected, realize the transmission cooperation of first pump body and second pump body, spline cooperation mode has higher cooperation joint strength in traditional cooperation modes such as connecting block or unsmooth key, the life of compound pump has been promoted, transmission stability and reliability.

In an exemplary embodiment, as shown in fig. 1 and 2, there is provided a compound pump, which includes a first pump body 10, a second pump body 20, and a transmission engagement structure 30, wherein a first pump shaft 11 and a second pump shaft 21 are disposed in the first pump body 10 and the second pump body 20, respectively, and the first pump shaft 11 and the second pump shaft 21 are disposed coaxially. The one end that is close to second pump shaft 21 of first pump shaft 11 is provided with first external spline structure 12, and the one end that is close to first pump shaft 11 of second pump shaft 21 is provided with second external spline structure 22, and spline housing 40 overlaps as transmission cooperation structure 30 and establishes the one end that is close to each other at first pump shaft 11 and second pump shaft 21, and first external spline structure 12 on the first pump shaft 11 and second external spline structure 22 on the second pump shaft 21 all are connected with spline housing 40's internal spline structure 41 cooperation.

The compound pump includes a first pump body 10, a second pump body 20 and a transmission matching structure 30, where the first pump body 10 and the second pump body 20 may be, for example, pump bodies with different functions in an automobile, and one end of the first pump body 10 is connected with one end of the second pump body 20. The first pump body 10 is provided with a first pump shaft 11 therein, the second pump body 20 is provided with a second pump shaft 21 therein, the first pump shaft 11 and the second pump shaft 21 may have circular cross-sectional shapes, for example, and the first pump shaft 11 and the second pump shaft 21 are disposed on the same axis. The first pump shaft 11 and the second pump shaft 21 have a preset distance therebetween, and the first pump body 10 and the second pump body 20 can be driven by synchronously rotating the first pump shaft 11 and the second pump shaft 21.

The first pump shaft 11 is provided with first external spline structure 12 near the one end of second pump shaft 21, and the one end of second pump shaft 21 near first pump shaft 11 is provided with second external spline structure 22, and drive cooperation structure 30 includes spline housing 40, and spline housing 40 is the annular structure, is provided with internal spline structure 41 along the inboard of spline housing 40 radial direction. The first external spline structure 12, the second external spline structure 22, and the internal spline structure 41 include teeth and grooves that are uniformly arranged and spaced in the circumferential direction of the first pump shaft 11, the second pump shaft 21, and the spline housing 40.

Illustratively, the ends of the first pump shaft 11 and the second pump shaft 21, which are close to each other, have the same diameter, and the ends of the first pump shaft 11 and the second pump shaft 21, which are close to each other, respectively penetrate into the spline housing 40 through openings on both sides of the spline housing 40, so that the spline housing 40 is sleeved at the ends of the first pump shaft 11 and the second pump shaft 21, which are close to each other, i.e. are provided with the first external spline structure 12 and the second external spline structure 22, the teeth of the first external spline structure 12 and the second external spline structure 22 are embedded in the grooves of the internal spline structure 41, and the teeth of the internal spline structure 41 are embedded in the grooves of the first external spline structure 12 and the second external spline structure 22, so that the first external spline structure 12 and the second external spline structure 22 are all in spline fit to form a spline connection. Because the first external spline structure 12 and the second external spline structure 22 are both in fit connection with the internal spline structure 41, rotation of the first pump shaft 11 or the second pump shaft 21 can be transmitted to the second pump shaft 21 or the first pump shaft 11 through the spline housing 40 when the first pump shaft 11 or the second pump shaft 21 rotates.

In this embodiment, the first pump body 10 and the second pump body 20 are respectively provided with the first pump shaft 11 and the second pump shaft 21 which are coaxial, and the first pump shaft 11 and the second pump shaft 21 are respectively provided with the first external spline structure 12 and the second external spline structure 22, the spline housing 40 is used as the transmission matching structure 30, the internal spline structure 41 of the spline housing 40 can be matched and connected with the first external spline structure 12 and the second external spline structure 22, so that the transmission matching of the first pump body 10 and the second pump body 20 is realized, the contact area of the spline matching connection is large, the bearing of larger load is high, the matching connection strength is high, and the service life, the transmission stability and the reliability of the composite pump are improved.

In some embodiments, as shown in fig. 2, the spline housing 40 is provided with a groove 51 on the inner circumference, the groove 51 being located between one end of the first pump shaft 11 adjacent to the second pump shaft 21 and a first end of the second pump shaft 21 adjacent to the first pump shaft 11, and the drive mating structure 30 further includes a wire retainer ring 50 partially embedded in the groove 51.

The spline housing 40 is provided with a groove 51 extending in the circumferential direction of the spline housing 40 in addition to the internal spline structure 41 on the inner circumference, the groove 51 is provided in the middle of one end of the first pump shaft 11 and the second pump shaft 21 which are close to each other, and the groove bottom shape of the groove 51 may be circular arc, for example. The driving engagement structure 30 further includes a wire retainer ring 50 in addition to the spline housing 40, the cross-sectional shape of the wire retainer ring 50 may be circular, for example, and the cross-sectional radius of the wire retainer ring 50 is slightly smaller than the radius of curvature of the groove 51, so that a portion of the wire retainer ring 50 is embedded in the groove 51, and another portion of the wire retainer ring 50 is located outside the groove 51. The bead ring 50 located outside the groove 51 overlaps with projected portions of the first pump shaft 11 and the second pump shaft 21 in the axial direction of the first pump shaft 11 and the second pump shaft 21.

The wire check ring 50 is partially embedded in the groove 51, that is, the wire check ring 50 is arranged in the middle of one end of the first pump shaft 11 and the second pump shaft 21, which is close to each other, the first pump shaft 11 and the second pump shaft 21 are separated by the other part of the wire check ring 50 positioned outside the groove 51, and a part of the wire check ring 50 is embedded in the groove 51, so that the wire check ring 50 cannot move along the circumferential direction of the spline housing 40, and further the movement of the spline housing 40 along the axial direction of the first pump shaft 11 and the second pump shaft 21 can be blocked by the wire check ring 50.

In the present embodiment, by providing the groove 51 on the inner periphery of the spline housing 40 and embedding a portion of the wire retainer ring 50 in the groove 51, the first pump shaft 11 and the second pump shaft 21 can be separated by another portion of the wire retainer ring 50 located outside the groove 51, preventing the first pump shaft 11 and the second pump shaft 21 from being in direct contact to cause serious wear. In addition, the steel wire retainer ring 50 also limits the movement of the spline housing 40 along the axial direction of the first pump shaft 11 and the second pump shaft 21, ensures that the spline housing 40 is always positioned at the initial connection position with the first pump shaft 11 and the second pump shaft 21, avoids serious abrasion or transmission failure caused by the deviation of the spline housing 40, and further improves the transmission stability and reliability of the compound pump.

In some embodiments, as shown in FIG. 2, the drive-fit structure 30 further includes a needle bearing 60 that fits over the periphery of the spline housing 40.

The transmission matching structure 30 comprises a needle bearing 60 in addition to the spline housing 40 and the wire retainer ring 50, wherein the needle bearing 60 is sleeved on the periphery of the spline housing 40, and the needle bearing 60 is used for bearing radial load and larger rotating speed. The needle bearing 60 is a bearing with a cylindrical needle 61 and the needle 61 is a rolling body, and the needle 61 is in direct contact with the outer peripheral surface of the spline housing 40, i.e., the needle 61 is located between the spline housing 40 and the cage of the needle bearing 60. The cross-sectional shape of the needle roller 61 is circular, and the needle roller 61 is long and small in diameter.

In this embodiment, the needle bearing 60 is sleeved on the periphery of the spline housing 40, so that the stability and reliability of transmission are further improved by utilizing the characteristic that the needle bearing 60 can bear a larger load and a larger rotating speed, and the running noise is reduced and the service life of the compound pump is prolonged by utilizing the characteristic that the friction resistance of the needle bearing 60 is small.

In some embodiments, as shown in fig. 1, the cavity structure 70 is disposed within the first pump body 10, the drive mating structure 30 is disposed within the cavity structure 70, an axial bore 80 is disposed at an end of the first pump body 10 adjacent to the second pump body 20, and an end of the second pump shaft 21 adjacent to the first pump shaft 11 enters the cavity structure 70 through the axial bore 80.

The first pump body 10 is internally provided with a cavity structure 70, the cavity structure 70 is arranged at one end, close to the second pump body 20, of the first pump body 10, the spline housing 40, the wire retainer ring 50 and the needle bearing 60 which are included in the transmission matching structure 30 are all arranged in the cavity structure 70, and one end, close to the second pump shaft 21, of the first pump shaft 11 is also arranged in the cavity structure 70. The end of the first pump body 10, which is close to the second pump body 20, is provided with a shaft hole 80, so that when the first pump body 10 is connected with the second pump body 20, the second pump shaft 21 can enter the cavity structure 70 through the shaft hole 80 to be connected with the spline structure in a matching way.

In this embodiment, the cavity structure 70 is disposed in the first pump body 10 and the transmission matching structure 30 is disposed in the cavity structure 70, so that the transmission matching structure 30 can be disposed in the first pump body 10, and the space occupied by the whole compound pump is reduced. The shaft hole 80 for the second pump shaft 21 to enter the cavity structure 70 is formed in one end, close to the second pump body 20, of the first pump body 10, so that the second pump shaft 21 can be connected with the spline structure in a matched mode when the first pump body 10 and the second pump body 20 are connected, and transmission matching of the first pump body 10 and the second pump body 20 is achieved.

In some embodiments, the first and second external spline structures 12, 22 and 41 each have 24 teeth, and the first and second external spline structures 12, 22 and 41 each have a modulus of 0.5mm.

The number of teeth of the spline structure refers to the number of teeth on the spline structure, and the modulus of the spline structure is used for representing the size of the teeth of the spline structure, and the number of teeth and the modulus of the spline structure are basic parameters which directly influence the transmission capacity and the service life of the spline structure. The first external spline structure 12, the second external spline structure 22 and the internal spline structure 41 have the same number of teeth and modulus, the number of teeth of the first external spline structure 12, the second external spline structure 22 and the internal spline structure 41 is set to 24, the modulus of the first external spline structure 12, the second external spline structure 22 and the internal spline structure 41 is set to 0.5mm, the number of teeth is set to 24, and the modulus is set to 0.5mm, which is the most suitable spline structure parameter selected after stress calculation.

In this embodiment, the first external spline structure 12, the second external spline structure 22 and the internal spline structure 41 are set to have the same number of teeth and modulus, so that the first pump shaft 11 and the second pump shaft 21 can realize the transmission of the first pump shaft 11 and the second pump shaft 21 through the spline housing 40 with the same spline parameters, the number of teeth is set to 24 according to the stress calculation result, and the modulus is set to 0.5mm, so that the first external spline structure 12, the second external spline structure 22 and the internal spline structure 41 are suitable for the product operation condition, and the stability and the reliability of the transmission are ensured.

In some embodiments, the first external spline structure 12, the second external spline structure 22, and the internal spline structure 41 are all involute splines.

The first external spline structure 12, the second external spline structure 22 and the internal spline structure 41 are all set as involute splines, the involute splines are spline structures with tooth parts shaped as involute, the involute splines are centered by adopting tooth profiles, and the pressure angle of the involute can be 45 degrees, for example. The involute spline has the characteristics of large tooth portion size, strong bearing capacity, easiness in automatic centering, high installation precision and the like.

In this embodiment, the first external spline structure 12, the second external spline structure 22 and the internal spline structure 41 are all set to involute splines, so that the axial rigidity under the same external dimension can be increased, the matching connection strength of the spline structures is improved, and the transmission stability and reliability of the compound pump are further improved. In addition, the involute spline is convenient to process and manufacture, material cost is reduced, and production efficiency is improved.

In some embodiments, the spline housing 40 is 42 chrome molybdenum.

42 chromium molybdenum (42 CrMo) is an alloy structural steel, has excellent strength and toughness and good machinability, the chemical components of the 42 chromium molybdenum comprise carbon (C), silicon (Si), manganese (Mn), sulfur (S), phosphorus (P), chromium (Cr) and molybdenum (Mo), and the 42 chromium molybdenum is the most suitable spline housing 40 material selected after the operation condition and the limit starting torque of the compound pump are calculated.

In this embodiment, the material of the spline housing 40 is 42 chrome molybdenum, which can meet the use requirement of the product, fully utilizes the excellent strength and toughness of 42 chrome molybdenum to improve the matching connection strength of the spline housing 40 and the first pump shaft 11 and the second pump shaft 21, and ensures the transmission stability and reliability.

In some embodiments, the first and second external spline structures 12, 22 are a clearance fit with the internal spline structure 41.

The first external spline structure 12 and the second external spline structure 22 are in clearance fit with the internal spline structure 41, that is, the tolerance zone of the groove parts is above the tolerance zone of the tooth parts, a certain gap is formed between the tooth parts of the first external spline structure 12 and the second external spline structure 22 and the groove parts of the internal spline structure 41, and a certain gap is also formed between the tooth parts of the internal spline structure 41 and the groove parts of the first external spline structure 12 and the second external spline structure 22.

In this embodiment, the first external spline structure 12 and the second external spline structure 22 are set to be in clearance fit with the internal spline structure 41, so that a certain clearance exists between the first external spline structure 12 and the second external spline structure 22 and the internal spline structure 41, dimensional errors generated in the manufacturing process of the spline structures can be compensated through the clearance, severe abrasion or transmission failure caused by connection and fit between the first external spline structure 12 and the second external spline structure 22 and the internal spline structure 41 is prevented, and the transmission stability and reliability of the compound pump are further improved.

In some embodiments, a steering vane pump is used as the first pump body 10 and a hydraulic brake gear pump is used as the second pump body 20.

The steering vane pump as the first pump body 10 is a pump body for assisting the rotation in the direction in the automobile, and the steering vane pump can assist the automobile in steering by the generated pressure. The hydraulic brake gear pump is a pump body used for braking in an automobile, and can provide braking pressure for a braking system in the braking process.

The steering vane pump, the hydraulic brake gear pump and the transmission matching structure 30 are integrated to form a composite pump, and the first pump shaft 11 arranged in the steering vane pump and the second pump shaft 21 arranged in the hydraulic brake gear pump are coaxially and synchronously rotated through the transmission matching structure 30, so that transmission between the steering vane pump and the hydraulic brake gear pump is realized.

In this embodiment, the first pump body 10 is a steering vane pump, the second pump body 20 is a hydraulic braking gear pump, and the steering vane pump, the hydraulic braking gear pump and the transmission matching structure 30 can be integrated to form a composite pump, so that the manufacturing cost and the occupied space of the steering vane pump and the hydraulic braking gear pump are reduced. In addition, realize the transmission between steering vane pump and the hydraulic braking gear pump through transmission cooperation structure 30, and spline cooperation mode has higher cooperation joint strength, has promoted compound pump's life, transmission stability and reliability.

In some embodiments, as shown in fig. 3, bolt holes 90 which are communicated with each other are correspondingly formed on the first pump body 10 and the second pump body 20, bolts are inserted into the bolt holes 90, and the first pump body 10 and the second pump body 20 are connected through bolt fastening.

The corresponding bolt holes 90 are formed in the first pump body 10 and the second pump body 20, the number of the bolt holes 90 can be correspondingly adjusted according to the sizes and the external shapes of the first pump body 10 and the second pump body 20, the hole wall of the bolt hole 90 in the first pump body 10 is flush with the hole wall of the corresponding bolt hole 90 in the second pump body 20, the bolt holes 90 in the first pump body 10 are communicated with the bolt holes 90 in the second pump body 20, and the bolts can be arranged in the bolt holes 90 in the first pump body 10 and the second pump body 20 in a penetrating mode to achieve fastening connection of the first pump body 10 and the second pump body 20.

In this embodiment, through corresponding set up the bolt hole 90 of intercommunication each other on first pump body 10 and second pump body 20, run through the fastening connection of mutual intercommunication bolt hole 90 can realize first pump body 10 and second pump body 20 through the bolt, connected mode is simple, fastening stability is strong, has guaranteed the connection compactness of first pump body 10 and second pump body 20, and then guarantees the overall structure intensity of compound pump.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any adaptations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It is to be understood that the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims (10)

1. The compound pump is characterized by comprising a first pump body, a second pump body and a transmission matching structure, wherein a first pump shaft is arranged in the first pump body, a second pump shaft is arranged in the second pump body, and the first pump shaft and the second pump shaft are coaxially arranged; a first external spline structure is arranged at one end, close to the second pump shaft, of the first pump shaft, and a second external spline structure is arranged at one end, close to the first pump shaft, of the second pump shaft; the transmission matching structure comprises a spline sleeve, the spline sleeve is sleeved at one end of the first pump shaft and one end of the second pump shaft, which are close to each other, and the first external spline structure and the second external spline structure are matched and connected with the internal spline structure of the spline sleeve.

2. The compound pump of claim 1, wherein a groove is provided on an inner circumference of the spline housing, the groove is provided between one ends of the first pump shaft and the second pump shaft that are close to each other, the drive fit structure further comprises a wire retainer ring, a portion of the wire retainer ring is embedded in the groove, and another portion of the wire retainer ring is located outside the groove.

3. The compound pump of claim 1, wherein the drive mating structure further comprises a needle bearing, the needle bearing being sleeved on the periphery of the spline housing.

4. A compound pump according to any one of claims 1 to 3, wherein a cavity structure is provided in the first pump body, the drive fit structure is provided in the cavity structure, an axial hole is provided in an end of the first pump body adjacent to the second pump body, and an end of the second pump shaft adjacent to the first pump shaft enters the cavity structure through the axial hole.

5. A compound pump as claimed in any one of claims 1 to 3 wherein the number of teeth of the first and second external and internal spline formations is 24 and the moduli of the first and second external and internal spline formations are 0.5mm.

6. A compound pump as claimed in any one of claims 1 to 3 wherein the first external spline formation, the second external spline formation and the internal spline formation are involute splines.

7. A compound pump according to any of claims 1-3, wherein the spline housing comprises 42 chromium molybdenum.

8. A compound pump as claimed in any of claims 1 to 3, wherein the first and second external spline formations are clearance fit with the internal spline formations.

9. A compound pump according to any one of claims 1 to 3, wherein the first pump body is a steering vane pump and the second pump body is a hydraulic brake gear pump.

10. A compound pump according to any one of claims 1-3, wherein the first pump body and the second pump body are correspondingly provided with mutually communicated bolt holes, and the first pump body and the second pump body are fastened and connected through bolts penetrating through the bolt holes.