JP4052580B2 - Plunger pump - Google Patents

Description

The present invention relates to a plunger pump incorporated in a slip control type vehicle brake hydraulic pressure control device.

  In a slip control type brake hydraulic pressure control device such as an anti-lock control system (commonly known as ABS), a traction control system (commonly known as TCS), or an electronic stability program (commonly known as ESP) of a vehicle brake, in one or more wheel cylinders A plunger pump is provided to control the pressure.

This type of plunger pump is disclosed in Patent Document 1.
FIG. 4 shows a cross-sectional view of the plunger pump 80 described in the above publication. The known plunger pump 80 includes at least a cylinder hole 82 having a different diameter formed in a pump housing (hydraulic block) 81 and a cylinder. A piston 83 accommodated in the smallest diameter hole of the hole 82, a closing plug 84 that seals an inlet portion having the largest diameter of the cylinder hole 82, and a check valve disposed on the upstream side and the downstream side of the pump chamber 85. A suction valve 86 and a discharge valve 88 having a structure are provided.
The piston 83 and the cylinder hole 82 are sealed by a seal ring 89 accommodated in the cylinder hole 82.

  A plunger pump in which the wall thickness of the closing plug is made thin is disclosed in Patent Document 2. The plunger pump 90 includes a closing plug 91 made of a steel plate as shown in FIG.

German Patent Application No. 10013858 JP-T-2002-514712

The conventional plunger pump described above has the following problems.
<1> In the plunger pump 80 described in Patent Document 1, the closing plug 84 is required to have a predetermined thickness in order to ensure strength. Therefore, although the inlet portion of the cylinder hole 82 has a large diameter, the volume of the high-pressure damper chamber 87 formed in the closing plug 84 is small by the thickness of the closing plug 84, so that the hydraulic pulsation is attenuated. The effect is not fully demonstrated.
In addition, since the entire plunger pump 80 has a large diameter, there is a problem that the entire hydraulic block 81 is enlarged and the cost is increased, and the degree of freedom in layout of other functional elements incorporated in the hydraulic block 81 is reduced. is there.
Further, since the components of the suction valve 86 and the discharge valve 88 are different, it is necessary to provide an assembly facility dedicated to each valve, and there are many types of components for both valves, which complicates parts management. There is also.

<2> In the case of the plunger pump 90 of Patent Document 2, the spring 93 that is a component of the discharge valve 92 is supported by the bottom of the planar shape of the closing plug 91, so that it is formed inside the closing plug 91. Due to the high pressure in the high-pressure damper chamber 94, the bottom of the closing plug 91 undergoes permanent deformation. If the bottom part of the closing plug 91 is permanently deformed, the appearance is deteriorated, and the mounting dimension of the spring 93 of the discharge valve 92 contacting the bottom part of the closing plug 91 is distorted, resulting in a problem that the discharge performance of the pump is lowered.

An object of the present invention is to provide a plunger pump that can be reduced in size and weight and has excellent quietness when the pump is operated.
Another object of the present invention is to provide a plunger pump that can share parts, can be easily manufactured, and can be manufactured at low cost.
An object of the present invention is to provide any one of the plunger pumps described above.

The present invention includes a cylinder hole formed in a pump housing, a piston accommodated in the cylinder hole and reciprocating in the cylinder, and an upstream side and a downstream side of a pump chamber in which the volume changes in accordance with the reciprocating motion of the piston. A plunger pump built in a vehicle brake hydraulic pressure control device having a check valve structure suction valve and a discharge valve respectively installed, and a closing means for a hole entrance of a cylinder hole is inserted into the cylinder hole, A cylindrical outer sleeve having one end fixed to the pump housing by caulking, and a closing sleeve inserted into the outer sleeve and having a metal plate formed into a substantially spherical shape whose bottom can be elastically deformed by cold forming. It consists of a cylinder, The said closure sleeve was fixed to the outer sleeve by press-fitting or welding.
Furthermore, the present invention provides the plunger pump described above, wherein the discharge sleeve is fixed between the stepped portion provided on the outer sleeve and the opening end of the closure sleeve, and the internal space of the closure sleeve blocked by the discharge valve is liquid It is characterized by being formed as a high-pressure damper chamber that attenuates pressure pulsations.
Furthermore, the present invention provides the plunger pump according to any one of the above-described plunger pumps, wherein the piston has a piston body having a small-diameter shaft portion, a sealing material sheathed on the small-diameter shaft portion, and is fitted to the small-diameter shaft portion. A piston assembly including a piston cap that sandwiches a sealing material therebetween, wherein the piston assembly is directly accommodated in a cylinder hole.
Furthermore, the present invention is characterized in that, in any of the plunger pumps described above, the discharge valve is composed of the same component as the suction valve.
Furthermore, the present invention is characterized in that in any of the plunger pumps described above, a protective cover is attached to the outside of the closing plug.

The present invention can obtain the following specific effects.
<1> A plunger pump that can be reduced in size and weight and is excellent in quietness when the pump is operated can be provided.
<2> It is possible to provide a plunger pump that can share components and can be easily manufactured and reduced in cost.

  Hereinafter, an example of a plunger pump according to the present invention will be described with reference to the drawings.

<1> Hydraulic block (pump housing)
FIG. 1 shows a cross-sectional view of the plunger pump 10 built in the hydraulic block 20. Although only a part of the hydraulic block 20 is shown in the drawing, the hydraulic block 20 includes hydraulic components (not shown) such as an electromagnetic valve, a reservoir, and an electric motor that drives a pump used for slip control. I have. Further, the hydraulic block 20 and a master cylinder (not shown) and the hydraulic block 20 and one or more wheel cylinders (not shown) are connected hydraulically.

<2> Cylinder hole Since the hydraulic block 20 also serves as the pump housing of the plunger pump 10, the hydraulic block is referred to as the pump housing 20 in the present invention.

  The aluminum pump housing 20 is provided with a cylinder hole 21 having a different diameter, and the cylinder hole 21 is increased or decreased in volume by a reciprocating motion of the piston assembly 30 and a small diameter portion 21 a that accommodates the piston assembly 30. And a large-diameter portion 21c on the hole inlet side. These holes 21a to 21c having different diameters are formed on the same axis.

A cam chamber 22 is formed in the back of the cylinder hole 21, and an eccentric cam 40 that is rotationally driven by an electric motor is accommodated in the cam chamber 22.
A stepped portion 21d is formed along the circumferential direction at the boundary between the medium diameter portion 21b and the large diameter portion 21c in the cylinder hole 21.

In the pump housing 20, a suction flow path 25 and a discharge flow path 26 that are formed in the radial direction facing the cylinder hole 21 are formed.
A suction valve 50 that allows only the flow from the suction flow path 25 into the pump chamber 23 is installed at a step portion in the middle of the suction flow path 25, and is fixed by a caulking portion 21e formed by plastic deformation of the pump housing 20. To do.

Between the suction flow path 25 and the discharge flow path 26, a pump chamber 23 whose volume is increased or decreased, and a high-pressure damper chamber 24 that attenuates the pulsation of the liquid discharged from the pump chamber 23 are formed.

<3> Piston Assembly The plunger pump 10 according to the present invention has a structure in which the piston assembly 30 is directly accommodated in the small diameter portion 21 a of the cylinder hole 21.

  That is, the piston assembly 30 includes a resin-made or metal piston cap in which a metal piston main body 32 having a small-diameter shaft portion 31 and a recess 33 that can be fitted to the small-diameter shaft portion 31 of the piston main body 32 are formed. 34, and a ring-shaped seal ring 35 and a backup ring 36 that are externally mounted on the small-diameter shaft portion 31 of the piston body 32.

  The annular seal ring 35 and the backup ring 36 are sandwiched between the piston main body 32 and the piston cap 34 and mounted so as to be substantially the same surface as the outer peripheral surface of the piston main body 31. The fitting depth between the small-diameter shaft portion 31 and the recess 33 is set in consideration of the cross-sectional widths of the seal ring 35 and the backup ring 36 so as not to be crushed and damaged.

  The exterior work of the seal ring 35 and the backup ring 36 is simple because it requires only a simple work of placing the piston cap 34 on the small-diameter shaft portion 31 of the piston body 32.

  The reason why the piston assembly 30 is adopted is to make the diameter of the medium diameter portion 21b of the cylinder hole 21 as small as possible and to accommodate the piston assembly 30 directly in the small diameter portion 21a of the cylinder hole 21.

  The seal ring 35 is an essential part for sealing between the small diameter portion 21a of the cylinder hole 21 and the pump chamber 23, but the backup ring 36 that functions to prevent the seal ring 35 from protruding during a high pressure load is essential. It may be omitted instead of parts.

  The piston cap 34 is formed to have substantially the same diameter as the outer diameter of the piston body 32, the right side is accommodated in the small diameter portion 21 a of the cylinder hole 21, and the left side protrudes into the pump chamber 23.

The piston return spring 38 is contracted between the stepped portion 37 formed on the opposite side of the recessed portion 33 of the piston cap 34 and the discharge valve 51.
The piston assembly 30 receives the spring force of the piston return spring 38 and is urged in the direction of the eccentric cam 40, and the right end surface of the piston body 32 abuts against the eccentric cam 40 and is supported. The integrity can be maintained without specially fixing the piston body 31 and the piston cap 34. Therefore, the piston assembly 30 can reciprocate in the cylinder hole 21 in a state in which the components are not separated from each other and the integrity is maintained.

<4> Cylinder Hole Closing Means In the present invention, a structure is adopted in which the opening at which the cylinder hole 21 is opened is closed by a double cylinder formed by the cylindrical outer sleeve 60 and the dome-shaped closing sleeve 70.

The outer sleeve 60 is a cylindrical body that covers the inside of the hole wall over a range from the hole entrance to the medium diameter portion 21 b of the cylinder hole 21, and has both a function as a sealing material and a function of reinforcing the closing sleeve 70.
The outer sleeve 60 includes a large-diameter cylindrical portion 61 formed on the left half of the cylindrical body, a small-diameter cylindrical portion 62 formed on the right half of the cylindrical body, a stepped portion 63 formed at the boundary between both cylindrical portions 61 and 62, It has an annular flange 65 formed by bending outward at the end of the large-diameter cylindrical portion 61, and is manufactured from a thin metal plate or the like.
On the peripheral surface on the large diameter portion 61 side, a plurality of through passages 64 are provided along one or the circumferential direction.

It is not necessary to ensure a large difference in diameter between the large-diameter cylindrical portion 61 and the small-diameter cylindrical portion 62, and it may be a dimensional difference that can support the discharge valve 51 by the stepped portion 63. In practice, it may be about the thickness of the outer sleeve 60. .
The outer diameter of the small-diameter portion 62 is dimensioned so that it can be press-fitted into the medium-diameter portion 21b of the cylinder hole 21 and sealed from the hole wall.

  The closing sleeve 70 is inserted into the outer sleeve 60 and functions as a lid member that seals and closes the inlet of the cylinder hole 21. In addition, the closing sleeve 70 sandwiches the discharge valve 51 between the stepped portion 63 of the outer sleeve 60. It is an attachment member for fixing, and a member for blocking the internal space by the discharge valve 51 to form the high-pressure damper chamber 24 inside, and cold forming (deep drawing) a thin metal plate ) To form.

In the present invention, it is important that the bottom 71 opposite to the opening of the closing sleeve 70 is formed into a substantially spherical shape by cold forming.
The “substantially spherical shape” does not mean only a perfect spherical surface having a constant radius, but includes an elliptical shape as shown in the figure. In other words, it does not include a plane, but includes all curved surfaces protruding outward.

  The reason why the closing sleeve 70 is formed into a substantially spherical shape by cold working is to increase the effect of damping the hydraulic pulsation in the high-pressure damper chamber 24 by elastically deforming the bottom 71 and to prevent the bottom 71 from being permanently deformed. This is to ensure

On the peripheral surface of the opening end of the closing sleeve 70, a through path 72 is provided by one or a plurality of grooves or holes.
The formation positions of the through-passage 64 of the outer sleeve 60 and the through-passage 72 of the closing sleeve 70 are not limited to the illustrated form, and the liquid in the high-pressure damper chamber 24 is passed through the peripheral surfaces of the closing sleeve 70 and the outer sleeve 60. It suffices if it is formed at a position where it can be discharged to the discharge channel 26.

  The outer peripheral surface where the outer sleeve 60 and the closing sleeve 70 overlap is fixed in a state in which a high sealing property is secured. As the fixing means, for example, any one of welding, press-fitting, screwing, and bonding, or a combination thereof may be appropriately performed.

In consideration of assembly accuracy and assembly work efficiency, the closing means for the cylinder hole 21 is set by inserting the closing sleeve 70 from the flange 65 side of the outer sleeve 60 and fixing it after setting the discharge valve 51 in the outer sleeve 60. It is desirable to make one unit in advance.
Further, the above-described components may be individually assembled in the cylinder hole 21 without being unitized.

  In addition, since the two leaves 60 and 70 that are the closing means for the cylinder hole 21 are made of a thin metal plate, the thickness of the sleeves 60 and 70 can be reduced, so that the volume of the high-pressure damper chamber 24 can be increased. This improves the damping performance of hydraulic pulsation.

The outer sleeve 60 inserted into the cylinder hole 21 is fixed by sealing with a caulking portion 21f formed by plastically deforming the periphery of the inlet of the cylinder hole 21 around the inlet of the cylinder hole 21, and between the peripheral surfaces of the sleeves 60 and 70. Since polymerization is performed while ensuring high sealing performance, the inlet of the cylinder hole 21 is closed while ensuring high sealing performance.

<5> Valve In the conventional plunger pump, both the suction valve and the discharge valve have different valve components.
On the other hand, in the present invention, a common valve is used for the suction valve 50 and the discharge valve 51 of the check valve structure to share the valves. Valve sharing can be achieved by sharing components.

First, the suction valve 50 will be described.
The suction valve 50 includes an annular valve seat 52, a ball valve 54 that closes the central hole 53 of the valve seat 52, a pot-shaped cage 55 that is externally mounted on the valve seat 52, and a compression between the ball valve 54 and the cage 55. The ball valve 54 is pressed against the central hole 53 of the valve seat 52 by the spring force of the spring 56 to close the flow path.
The skirt portion of the cage 55 is fixed so as to surround the side surface of the valve plate 52, and the cylindrical portion has an opening structure through which liquid can pass.

Since the discharge valve 51 is the same in structure and dimensions as the suction valve 50 described above, the parts corresponding to the suction valve 50 in FIG. 2 are assigned the same reference numerals, and the description of the discharge valve 51 is omitted. .
In FIG. 2, reference numeral 39 denotes a spring receiver provided in contact with one surface of the valve seat 52 of the discharge valve 51, and is not an essential component.
Further, when it is desired to set the valve opening pressures of the discharge valve 51 and the suction valve 50 to different values, it is only necessary to make the springs 56 different.

<6> Assembly of Plunger Pump An example of a method for assembling the plunger pump 10 will be described.
In FIG. 1, after the piston assembly 30 is inserted into the small diameter portion 21 a of the cylinder hole 21, the piston return spring 38 is inserted into the cylinder hole 21.
Next, while the piston return spring 38 is contracted, the cylinder hole closing means in which the outer sleeve 60, the discharge valve 51, and the closing sleeve 70 are unitized is pushed into the cylinder hole 21.
Then, the periphery of the inlet of the cylinder hole 21 is caulked in an annular shape, and the flange 65 of the outer sleeve 60 is fixed, thereby closing the inlet of the cylinder hole 21 while ensuring high sealing performance.
Finally, a flat protective cover 27 is attached to the outside of the polymer of the inner sleeve 60 and the closing sleeve 70 to obtain the plunger pump 10 shown in FIG.
The protective cover 27 may be omitted.

  The conventional plunger pump has a structure in which a liner is disposed over at least the piston sliding range in the cylinder hole, the piston is accommodated in the liner, and a sealing material is installed on the liner side. The large diameter had to be set to allow for the thickness of the liner and the thickness of the sealing material.

On the other hand, in the present invention, the piston assembly 30 with the seal ring 35 is employed, and the diameter of the small diameter portion 21a of the cylinder hole 21 that accommodates the piston assembly 30 can be made as small as possible. Since the outer sleeve 60 and the closing sleeve 70 which are the closing means of the cylinder hole 21 are manufactured with a thin material and the maximum diameter of the cylinder hole 21 can be reduced, the plunger pump 10 is made to have a small diameter as a whole. Thus, the hydraulic block 20 can be reduced in size and weight, and there are many advantages in that the degree of freedom in layout of other functional elements incorporated in the hydraulic block 20 is increased.

<7> Pump Operation With the eccentric rotational movement of the eccentric cam 40, the piston assembly 30 slides in the small diameter portion 21 a of the cylinder hole 21.
Along with the reciprocating motion of the piston assembly 30 and the opening / closing valve operation of the two valves 50 and 51, the liquid sucked into the pump chamber 23 from the suction passage 25 is discharged to the high pressure damper chamber 24, and from the high pressure damper chamber 24. It is possible to discharge to the discharge flow path 26 through the through passages 72 and 64 of the closing sleeve 70 and the outer sleeve 60.

The pulsation of the hydraulic pressure occurs when the liquid in the pump chamber 23 is discharged to the high pressure damper chamber 24.
In the present invention, since the damping effect of the hydraulic pulsation due to the large volume of the closing sleeve 70 and the damping effect of the hydraulic pulsation due to the elastic deformation of the bottom of the closing sleeve 70 are exhibited, the plunger pump 10 Improves quietness.
The bottom 71 of the closing sleeve 70 allows elastic deformation, but does not permanently deform, so there is no fear of damaging the appearance.
Further, since the spring 56 of the discharge valve 51 is not in contact with the bottom 71, there is no problem that the discharge performance of the pump deteriorates.

  In general, the pump efficiency (ratio of the effective discharge flow rate to the theoretical pump discharge flow rate) increases as the volume of the pump chamber 23 decreases, and the pump process compression ratio increases and the pump efficiency improves. For this reason, in the present invention, the cylinder hole 21 can be designed to have a small diameter and the volume of the pump chamber 23 can be reduced, so that the pump efficiency is improved.

Of course, the plunger pump 10 of the present invention may be provided in a plurality of sets with respect to the hydraulic block 20.

Sectional view of the plunger pump according to the present invention Partial enlarged cross-sectional view of the plunger pump near the discharge valve Partial enlarged cross-sectional view of the plunger pump near the suction valve Sectional view of a conventional plunger pump on which the present invention is based Cross section of another conventional plunger pump

Explanation of symbols

10 ... Plunger pump 20 ... Pump housing (hydraulic block)
21 ... Cylinder hole 21a ... Cylinder hole small diameter part 21b ... Cylinder hole medium diameter part 21c ... Cylinder hole large diameter part 22 ... Cam chamber 23 ... Pump chamber 24 ...・ High pressure damper chamber 25... Suction passage 26... Discharge passage 30 .piston assembly 31 .small diameter shaft portion 32 .piston body 33. Piston cap 35 ... Seal ring 36 ... Backup ring 40 ... Eccentric cam 50 ... Suction valve 51 ... Discharge valve 52 ... Valve seat 53 ... Center hole 54 ... Ball valve 55 ... Cage 56 ... Spring 60 ... Outer sleeve 61 ... Large diameter cylindrical portion 62 ... Small diameter cylindrical portion 63 ... Stepped portion 64 ... Outer sleeve through passage 65 ... Flange 70 ... Closure sleeve 71 ... through passage of the bottom 72 ... closure sleeve of the closure sleeve

Claims (5)

A cylinder hole formed in the pump housing, a piston housed in the cylinder hole and reciprocating in the cylinder, and a reverse installed on the upstream side and the downstream side of the pump chamber in which the volume increases or decreases as the piston reciprocates. A plunger pump built in a vehicle brake hydraulic pressure control device having a suction valve and a discharge valve of a stop valve structure,
A cylindrical outer sleeve in which a closing means at the hole entrance of the cylinder hole is inserted into the cylinder hole and fixed at one end to the pump housing by caulking;
It is inserted into the outer sleeve, and consists of a double cylinder with a closing sleeve formed in a substantially spherical shape whose bottom can be elastically deformed by cold forming processing of a metal plate,
The closing sleeve is fixed to the outer sleeve by press fitting or welding,
Plunger pump. A discharge valve is sandwiched and fixed between the stepped portion provided on the outer sleeve and the opening end of the closing sleeve, and the internal space of the closing sleeve blocked by the discharge valve is formed as a high-pressure damper chamber that attenuates hydraulic pulsation. The plunger pump according to claim 1, wherein: A piston assembly comprising a piston main body having a small-diameter shaft portion, a sealing material packaged on the small-diameter shaft portion, and a piston cap that fits the small-diameter shaft portion and sandwiches the sealing material between the piston main body and the piston. The plunger pump according to claim 1 or 2, wherein the piston assembly is directly accommodated in the cylinder hole. The plunger pump according to any one of claims 1 to 3, wherein the discharge valve is composed of the same component as the suction valve. The plunger pump according to any one of claims 1 to 4, wherein a protective cover is attached to the outside of the closing plug.

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