KR101421838B1 - Piston pump having spline coupling - Google Patents

Abstract

The present invention discloses a piston pump with a parallel connected spline coupling. The piston pump having the parallel connection type spline coupling includes: a casing (110) forming an appearance; A front shaft 120a rotatably disposed in a central region of the front pump 100a disposed at one side of the casing 110; A rear shaft 120b rotatably disposed in a central region of a rear pump 100b disposed on the other side of the casing 110; A spline coupling (160) fixed to a connection region between the front shaft (120a) and the rear shaft (120b); And a needle bearing 170 connected in parallel with the spline coupling 160 at a radially outer side of the spline coupling 160.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a piston pump having a splined coupling,

The present invention relates to a piston pump having a parallel connection type spline coupling, and more particularly, to a piston pump capable of connecting a front shaft and a rear shaft in parallel so as to shorten the total length of a conventional rotary pump, And a parallel connection type spline coupling capable of eliminating the occurrence of external leakage due to deterioration of the run out of the oil seal assembly.

In a construction equipment such as an excavator, a pump is driven by rotational kinetic energy provided by an engine such as an internal combustion engine.

At this time, the pump supplies operating fluid such as an actuator such as a boom, an arm, a swing motor, a traveling motor and the like, and a variable displacement type piston pump whose displacement is variable, such as an axial pump, It is common.

FIG. 1 is an internal structural view of a conventional piston pump, and FIG. 2 is an exploded perspective view of a spline coupling applied to FIG.

Referring to these figures, a piston pump, also referred to as a so-called parallel axial piston pump, has a structure in which a front pump 1a and a rear pump 1b are connected to each other .

This piston pump is configured such that the cylinder blocks 4a and 4b are rotated at a high speed by a front shaft 2a and a rear shaft 2b interconnected with a plurality of pistons inserted into the cylinder (piston chamber) And the piston inserted into the cylinder simultaneously reciprocates in the cylinder simultaneously with the high-speed rotation of the cylinder blocks 4a and 4b, thereby sucking and discharging the working fluid through each port.

Such a piston pump has been widely applied to a swash plate type swash plate having slanted swash plates (3a, 3b) in a casing (not shown in FIG. 1).

In the swash plate type axial piston pump to which the swash plates 3a and 3b are applied, the flow rate of the hydraulic fluid discharged from the pump can be determined according to the inclination (swing angle) of the swash plates 3a and 3b.

As shown in FIG. 1, the front shaft 2a and the rear shaft 2b are connected to each other by a simple structure spline coupling 6 (FIG. 1) so that the front pump 1a and the rear pump 1b are connected to each other. ).

The spline coupling 6 has a conventional structure in which a plurality of spline gears 6b are formed along the circumferential direction in the coupling body 6a having a cylindrical structure as shown in Fig.

On the other hand, a needle bearing (7) is connected to the periphery of the spline coupling (6). At this time, the needle bearings 7 are connected to the front shaft 2a and the rear shaft 2b, respectively, at both end regions of the spline coupling 6 along the longitudinal direction of the front shaft 2a and the rear shaft 2b.

In other words, in the case of the prior art, the spline coupling 6 and the needle bearing 7 have a structure in which they are connected in series along the longitudinal direction of the front shaft 2a and the rear shaft 2b.

1 and 2, when the spline coupling 6 and the needle bearing 7 are connected in series along the longitudinal direction of the front shaft 2a and the rear shaft 2b, There is a problem that the length of the battlefield is inevitably long.

Structurally, the connection portions of the front shaft 2a and the rear shaft 2b are weak, leading to instability of the rotary group, resulting in deterioration of the run-out of the oil seal assembly , There is a high possibility that external leakage will occur. Therefore, it is necessary to supplement the structure in consideration of this point.

Korean Patent Application No. 10-2004-0099069

Accordingly, the present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a front shaft and a rear shaft which can be connected in parallel, And a parallel connection type spline coupling capable of eliminating the occurrence of external leakage due to deterioration of the run out of the oil seal assembly.

In order to achieve the above-described object, the present invention provides a casing comprising: a casing forming an appearance; A front shaft rotatably disposed in a central region of a front pump disposed at one side of the casing; A rear shaft rotatably disposed in a central region of a rear pump disposed on the other side of the casing; A spline coupling fixed to a connection region between the front shaft and the rear shaft; And a needle bearing connected in parallel with the spline coupling at a radially outer side of the spline coupling.

The present invention further provides the following specific embodiments with respect to the above embodiment of the present invention.

According to an embodiment of the present invention, the spline coupling comprises: a coupling body; A non-gear section for supporting the front shaft and the rear shaft, each of the sections being formed as a gearless section on inner wall surfaces of both ends of the coupling body; And a spline gear section formed on the inner wall surface of the coupling body between the shaft support non-gear section.

According to an embodiment of the present invention, the coupling body of the region where the front shaft and the rear shaft are in contact with each other is provided with a first lubricant supply portion for supplying lubricant.

According to an embodiment of the present invention, a space between the front shaft, the rear shaft, and the non-gear section for supporting the shaft defines a second lubricant supply portion for supplying lubricant.

According to the present invention, since the front shaft and the rear shaft can be connected in parallel, the total length can be shortened compared with the conventional one. Further, unstable elements of the rotary group can be eliminated and the leakage leakage due to deterioration of the run- There is provided a piston pump having a parallel-connected spline coupling capable of eliminating the occurrence of the above-mentioned problems.

1 is an internal structural view of a conventional piston pump.
Fig. 2 is an exploded perspective view of the spline coupling applied to Fig. 1; Fig.
3 is a structural view of a piston pump having a parallel connected spline coupling according to an embodiment of the present invention.
Fig. 4 is an enlarged view of the spliced coupling region of the parallel connection in Fig. 3;
FIG. 5 is a view showing a process of supplying lubricating oil in FIG.
6 is a perspective view of Fig.
7 is an enlarged view of the spline coupling.
8 is an exploded perspective view of the spline coupling.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 3 is a structural view of a piston pump having a parallel connection type spline coupling according to an embodiment of the present invention. FIG. 4 is an enlarged view of a spline coupling region connected in parallel in FIG. Fig. 6 is a perspective view of Fig. 4, Fig. 7 is an enlarged view of the spline coupling, and Fig. 8 is an exploded perspective view of the spline coupling.

Referring to these drawings, a piston pump having a parallel-connected spline coupling of the present embodiment has a structure in which a front pump 100a and a rear pump 100b are coupled to one casing 110 .

The front pump 100a and the rear pump 100b are symmetrical to each other, but their internal structures are substantially the same.

The piston pump of this embodiment will be described with reference to FIG. First, the casing 110 forms the outer appearance of the piston pump of this embodiment.

3 is only one example, the scope of right of the present invention need not be limited to the shape of the drawings.

 At the rear end of the casing (110), a valve plate (150) having suction and discharge ports is provided.

A rotary group is formed in each of the front pump 100a and the rear pump 100b. The rotary group may include driving components such as shafts 120a and 120b, cylinder blocks 140a and 140b, and swash plates 130a and 130b.

The shafts 120a and 120b include a front shaft 120a rotatably provided in a central region of the front pump 100a and a rear shaft 120b rotatably provided in a central region of the rear pump 100b.

The front shaft 120a and the rear shaft 120b are connected by a spline coupling 160 and a needle bearing 170, which will be described later.

An oil seal 115 is provided at the front end of the front shaft 120a. And the oil seal 115 serves to prevent the occurrence of external leakage at the corresponding position.

The swash plate 130a.130b is sloped on one side of each of the front shaft 120a and the rear shaft 120b. The flow rate of the operating fluid discharged from the pump can be determined according to the inclination (the gentle angle) of the swash plate 130a.

The swash plate 130a.130b is connected to the sockets 133a and 133b, the conrods 134a and 134b and the pistons L and 135a and 135b.

The cylinder blocks 140a and 140b are spline coupled to the front shaft 120a and the rear shaft 120b, respectively.

The cylinder blocks 140a and 140b are provided with a plurality of piston chambers (or cylinders) and are co-rotated with the shafts 120a and 120b.

In each piston chamber, a piston 132 joined to a shoe (not shown) in which a ball B at one end abuts against the swash plate 130a. 130b is inserted.

The inner space of each piston chamber can communicate with the suction and discharge ports of the valve plate 150 through the openings formed in the rear surface of the casing 110 while the cylinder blocks 140a and 140b rotate.

Meanwhile, when the piston pump of the present embodiment is operated, pressure fluctuations may occur in the respective piston chambers formed in the cylinder blocks 140a and 140b.

The process in which the pressure fluctuates in one piston chamber includes a pressure rising process and a pressure falling process.

This pressure fluctuation acts as an excitation force to vibrate the entire device and, as a result, generate noise. If the pressure fluctuates suddenly during the pressure increasing process and the pressure decreasing process, not only the noise increases but also the noise The high frequency component becomes large, which may eventually generate a noise that is uncomfortable to the ear.

Further, in the case of the swash plate type axial piston pump in which the fluid is sucked and discharged by rotating the cylinder blocks 140a and 140b with respect to the inclined swash plate 130a.130b, the pressure pulsation due to the flow pulsation is inevitably And this pressure pulsation also acts as an exciting force for exciting the structure. Thus, the pressure pulsation is also a main cause of the hydraulic system noise. In this respect, the applicant of the present invention has also applied for and applied for many improved technologies.

Meanwhile, the front shaft 120a and the rear shaft 120b are connected by a spline coupling 160 and a needle bearing 170, respectively.

In the present embodiment, the spline coupling 160 and the needle bearing 170 are arranged in parallel in a manner that is out of the tandem method as in the prior art FIG. 1, and the front shaft 120a and the rear shaft 120b, Are coupled to each other.

In such a case, it is possible to shorten the total length of the rotary cylinder and further eliminate the unstable elements of the rotary group, thereby eliminating the occurrence of external leakage due to deterioration of the run-out of the assembly of the oil seal 115 (see FIG. 3) .

The spline coupling 160 and the needle bearing 170 will now be described in more detail with reference to Figures 4-8.

First, the spline coupling 160 is fixed to the connection region of the front shaft 120a and the rear shaft 120b.

The spline coupling 160 includes a coupling body 161, a pair of non-gear sections 162 for supporting the shaft, and a spline gear section 163.

The coupling body 161 forms the appearance of the spline coupling 160. The inside can have an empty pipe shape and can be made of a rigid metal material.

The pair of shaft supporting non-gear sections 162 are formed in a section without gears on the inner wall surfaces of the both ends of the coupling body 161. The front shaft 120a and the rear shaft 120b are disposed and supported on the pair of shaft supporting non-gear sections 162. [

In other words, the non-gear section 162 for supporting the shaft forms a smooth surface without gear processing, and the front shaft 120a and the rear shaft 120b are disposed and supported.

Accordingly, there is an advantage that the front shaft 120a and the rear shaft 120b can be supported more stably and firmly than in the prior art.

In addition, since strong bending or torsional loads are applied to the shafts 120a and 120b of the swash plate type piston pump according to the present embodiment, the shafts 120a and 120b may be deformed due to such load.

If deformation occurs in the shafts 120a and 120b, this deformation leads to instability of the rotary group, which results in a decrease in the efficiency of the pump.

In addition, such a phenomenon may cause an occurrence of external leakage due to deterioration of the run out of the assembly of the oil seal 115.

However, as the present embodiment, the front shaft 120a and the rear shaft 120b are disposed and supported in the shaft supporting non-gear section 162 of the spline coupling 160, thereby improving the efficiency of the pump. (See FIG. 3) of the oil seal 115 (see FIG. 3).

The spline gear section 163 is formed on the inner wall surface of the coupling body 161 between the shaft supporting non-gear section 162.

The coupling body 161 can be splined to the front shaft 120a and the rear shaft 120b in the region of the spline gear section 163 to form a single body. Therefore, the coupling body 161 can also be rotated during rotation of the front shaft 120a and the rear shaft 120b.

On the other hand, the needle bearing 170 is connected in parallel with the spline coupling 160 at the radially outer side of the spline coupling 160.

The needle bearings 170 are used for smooth rotation as bearings using elongated cylindrical rollers such as needles.

When the front shaft 120a and the rear shaft 120b are connected to each other while the spline coupling 160 and the needle bearing 170 are disposed in parallel to each other, the overall length can be further shortened.

For reference, since the mounting space of the pump may be limited because the accessory accessories of the engine tend to increase in response to the exhaust gas regulation in recent years, the electric field of the pump may be one of the main design elements. This effect can be provided by arranging the coupling 160 and the needle bearing 170 in parallel.

5 to 7, the coupling body 161 of the spline coupling 160 in a region where the front shaft 120a and the rear shaft 120b are in contact with each other is provided with a first lubricant supply portion 164 are formed.

At this time, the first lubricant supply portion 164 has a shape of a hole passing through the thickness of the coupling body 161. A plurality of first lubricant supply portions 164 may be disposed along the circumferential direction of the coupling body 161 as needed.

6, the space between the front shaft 120a and the rear shaft 120b and the non-gear section 162 for shaft support in the spline coupling 160 is connected to the second A lubricant supply portion 165 is formed.

The second lubricant supply portion 165 is not separately machined but is formed naturally by the space between the shafts 120a and 120b and the shaft portion for supporting the shaft 162 for supporting the shaft.

Since the first lubricant supply portion 164 and the second lubricant supply portion 165 are formed in the spline coupling 160 as described above, the lubricant can be supplied through the first lubricant supply portion 164 and the second lubricant supply portion 165 And it is possible to suppress the abrasion.

As described above, if the lubrication is not smooth due to the bending or torsional load applied to the shafts 120a and 120b, fretting wear is likely to occur.

For reference, fretting wear refers to a phenomenon in which a part of the surface material falls off when a vibration load of a small amplitude is applied to the surface between two objects which are subjected to a relative-contact friction movement.

The main feature is the occurrence of reddish-brown debris on the contact surface.

This by-product is an oxidation material of iron, and its hardness is 2 to 3 times higher than that of the raw material, so that secondary abrasive wear can be generated.

However, in the case of this embodiment, since the lubricant is smoothly supplied through the first and second lubricant supply parts 164 and 165, the occurrence of fretting wear can be reduced.

According to the piston pump of this embodiment having such a structure and an action, the front shaft 120a and the rear shaft 120b can be connected in parallel so that the total length can be shortened, and furthermore, So that the occurrence of external leakage due to deterioration of the run-out of the oil seal assembling part 115 can be solved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

100a: front pump 100b: rear pump
110: Casing 115: Oil seal
120a: front shaft 120b: rear shaft
130a, 130b: swash plate
140a, 140b: cylinder block 150: valve plate
160: Spline coupling 161: Coupling body
162: Non-gear section for shaft support 163: Spline gear section
164: first lubricant supply part 165: second lubricant supply part

Claims (4)

delete A casing (110) forming an appearance;
A front shaft 120a rotatably disposed in a central region of the front pump 100a disposed at one side of the casing 110;
A rear shaft 120b rotatably disposed in a central region of a rear pump 100b disposed on the other side of the casing 110;
A spline coupling (160) fixed to a connection region between the front shaft (120a) and the rear shaft (120b); And
And a needle bearing (170) connected in parallel with the spline coupling (160) at a radially outer side of the spline coupling (160)
The spline coupling (160)
A coupling body 161;
A non-gear section 162 for shaft support, which is formed on the inner wall surfaces of both ends of the coupling body 161 and has no gears, for supporting the front shaft 120a and the rear shaft 120b; And
And a spline gear section (163) formed on the inner wall surface of the coupling body (161) between the shaft supporting non-gear section (162).
3. The method of claim 2,
Wherein the coupling body (161) in a region where the front shaft (120a) and the rear shaft (120b) are in contact with each other is provided with a first lubricant supply portion (164) for supplying lubricant oil. A piston;
3. The method of claim 2,
Wherein a space between the front shaft (120a), the rear shaft (120b), and the shaft supporting non-gear section (162) forms a second lubricant supply portion (165) for supplying lubricant. A piston pump having a splined coupling.

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