JP2013189965A - Piston pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a pump axial length of a piston pump, and to reduce an occupied area in a pump radial direction of the piston pump.SOLUTION: A suction valve 28 for opening/closing a suction port 161 is constituted of a suction side elastic piece 281 which consists of a plate material or a wire rod formed in an arc shape, and generates elastic force in a closing direction of the suction port 161, and arranged along an inner circumferential surface of a cylinder 16. Thus, a pump axial length of a piston pump can be reduced due to both the omission of a groove of an outer circumferential surface of a piston 18 and reduction of a pump axial length of the suction valve 28. Further, since the suction valve 28 is arranged on the inner circumferential side of the cylinder 16, an occupied area in the pump radial direction of the piston pump can be reduced.

Description

  The present invention relates to a piston pump that sucks and discharges fluid as a piston reciprocates.

  In a conventional piston pump, the piston reciprocates in the cylinder and the volume of the pump chamber changes, so that the suction valve opens in the suction stroke, and fluid is sucked into the pump chamber from the suction passage, and the discharge is discharged in the discharge stroke. The valve is opened, and fluid is discharged from the pump chamber to the discharge passage (see, for example, Patent Documents 1 and 2).

  In the piston pump disclosed in Patent Document 1, the suction port of the cylinder and the pump chamber are communicated with each other via an annular groove formed in the outer peripheral surface of the piston or a communication hole formed in the piston. Yes. The suction valve and the discharge valve are provided with a spherical valve body and a coil spring. The suction valve is disposed in the pump chamber, the discharge valve is disposed outside the pump chamber, and the suction valve and the discharge valve are disposed in series in the pump axial direction.

  In the piston pump disclosed in Patent Document 2, the suction valve includes a spherical valve body and a coil spring, and is disposed in the pump housing. The discharge valve includes a spherical valve body and a coil spring, and is disposed outside the pump chamber.

Japanese Patent Laid-Open No. 10-246178 Special table 2003-528244 gazette

  However, since the piston pump shown in Patent Document 1 has an annular groove on the outer peripheral surface of the piston, the length of the piston in the pump axial direction becomes long. Further, since the valve body and the coil spring of the suction valve are arranged in series in the pump axial direction, the length in the pump axial direction of the pump chamber in which the valve body and the coil spring are accommodated becomes long. Furthermore, since the suction valve and the discharge valve are arranged in series in the pump axial direction, the length of the piston pump in the pump axial direction becomes long. Therefore, the piston pump disclosed in Patent Document 1 has a problem that the axial length of the pump is extremely long.

  On the other hand, in the piston pump shown in Patent Document 2, since the suction valve is disposed in the pump housing, the pump axial length is shorter than that of the piston pump shown in Patent Document 1, but the suction valve is a pump. Since it is arranged at a position away from the axis in the pump radial direction, there is a problem that the occupied area in the pump radial direction of the piston pump increases.

  The present invention has been made in view of the above points, and it is an object of the present invention to shorten the length of the piston pump in the pump axial direction and to reduce the occupied area of the piston pump in the pump radial direction.

  In order to achieve the above object, according to the first aspect of the present invention, the suction port (161) for introducing a fluid from the external suction passage (103) to the pump chamber (20) and the fluid in the pump chamber are connected to the external discharge passage ( 104) and a cylindrical cylinder (16) having a discharge port (162) for discharging into the cylinder, and slidably inserted into the cylinder, partitioning the pump chamber together with the cylinder, and changing the volume of the pump chamber by reciprocation. A piston (18), a suction valve (28) that opens and closes the suction port, and a discharge valve (30) that opens and closes the discharge port. One end of the suction port opens to the inner peripheral surface of the cylinder. And a suction side elastic piece (281) that generates an elastic force in the direction of closing the suction port, and the suction side elastic piece is formed in an arc shape and disposed along the inner peripheral surface of the cylinder. It is characterized by comprising.

  According to this, the fact that the groove on the outer peripheral surface of the piston is not necessary and the pump axial length of the suction valve is shortened, the pump axial length of the piston pump can be shortened. . Further, since the suction valve is arranged on the inner peripheral side of the cylinder, the occupied area in the pump radial direction of the piston pump can be reduced.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is front sectional drawing which shows the structure of the piston pump which concerns on 1st Embodiment of this invention. It is a front view of the suction valve of FIG. It is a right view of the suction valve of FIG. It is a perspective view of the suction valve of FIG. It is sectional drawing which follows the VV line of FIG. It is a front view of the discharge valve of FIG. It is a right view of the discharge valve of FIG. It is a perspective view of the discharge valve of FIG. It is A arrow view of the discharge valve vicinity of FIG. It is sectional drawing which follows the XX line of FIG. It is front sectional drawing which shows the structure of the piston pump which concerns on 2nd Embodiment of this invention. It is front sectional drawing which shows the structure of the piston pump which concerns on 3rd Embodiment of this invention. It is sectional drawing which follows the XIII-XIII line | wire of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described. The pump of this embodiment is used as a pump for increasing the pressure of brake fluid in a vehicle brake device that performs ABS control.

  As shown in FIG. 1, a metal housing 10 made of, for example, aluminum is formed with a cylindrical housing-shaped first housing hole 101 and a second housing hole 102 orthogonal to the first housing hole 101. . One end side of the first housing hole 101 opens to the outside, and the inner diameter gradually decreases from the outer opening end toward the inside. An inner opening end of the first housing hole 101 communicates with the second housing hole 102.

  Further, the housing 10 is formed with a suction passage 103 that opens to the first housing hole 101 and a discharge passage 104 that opens to the first housing hole 101. Then, brake fluid is sucked into a pump chamber 20 described later via the suction passage 103 and the like, and the brake fluid whose pressure has been increased is discharged from the pump chamber 20 to the discharge passage 104.

  In the second housing hole 102, a rotating shaft 12 of driving means (not shown) (for example, an electric motor) is arranged. The rotary shaft 12 is integrally formed with a cam 14 that is eccentric with respect to the rotation center of the rotary shaft 12.

  A bottomed cylindrical cylinder 16 made of metal is press-fitted into the first housing hole 101. A cylindrical piston 18 made of metal is slidably inserted into the cylinder 16. A pump chamber 20 is defined by the cylinder 16 and the piston 18.

  The piston 18 is urged toward the cam 14 by a return spring 22 disposed in the pump chamber 20 and is in contact with the cam 14. The volume of the pump chamber 20 changes as the piston 18 reciprocates as the rotary shaft 12 rotates.

  A suction port 161 that penetrates in the radial direction and communicates the suction passage 103 and the pump chamber 20 is formed in the cylindrical portion of the cylinder 16. The suction port 161 communicates directly with the pump chamber 20 without using a groove or a communication hole formed in the piston as in a conventional piston pump. Further, in this example, two suction ports 161 are arranged at positions shifted by 180 ° in the cylinder circumferential direction. However, the number of inlets 161 may be one, or three or more.

  A discharge port 162 that penetrates in the radial direction and communicates the discharge passage 104 and the pump chamber 20 is formed in the cylindrical portion of the cylinder 16.

  Between the first housing hole 101 and the piston 18, a seal member 24 that prevents the brake fluid whose pressure has been increased in the pump chamber 20 from leaking from the outer peripheral surface of the piston 18 to the second housing hole 102 side, and an annular shape A guide member 26 is disposed.

  The seal member 24 is formed of a resin in an annular shape, and an inner peripheral surface thereof is formed of an elastic body such as a rubber and a seal ring 241 that slides with the piston 18, and an inner peripheral surface thereof abuts on the seal ring 241. In addition, an O-ring 242 whose outer peripheral surface is in contact with the first housing hole 101 is provided.

  A suction valve 28 for opening and closing the suction port 161 is disposed on the inner peripheral side of the cylinder 16. As shown in FIGS. 1 to 4, the suction valve 28 is configured by a suction-side elastic piece 281 formed of a metal plate material in an arc shape, and is disposed along the inner peripheral surface of the cylinder 16. . A suction side protrusion 281a that is bent so as to protrude outward in the radial direction is provided at the circumferential intermediate portion of the suction side elastic piece 281.

  As shown in FIGS. 1 and 5, an annular suction side accommodation groove 163 is formed on the inner peripheral surface of the cylinder 16, and the suction side elastic piece 281 is accommodated in the suction side accommodation groove 163. The suction port 161 is opened in the suction side accommodation groove 163. A suction-side insertion hole 164 is formed in the suction-side accommodation groove 163, and the suction-side protrusion 281a is inserted into the suction-side insertion hole 164.

  A part of the suction side elastic piece 281 contacts and separates from the bottom surface of the suction side accommodation groove 163 to open and close the suction port 161 and generate an elastic force in a direction to close the suction port 161. More specifically, when the pressure in the pump chamber 20 is lower than the pressure in the suction passage 103 by a predetermined value or more, the suction side elastic piece 281 is elastically deformed against the elastic force generated by itself and faces the suction port 161. The vicinity of the part to be opened is separated from the inner circumferential surface of the cylinder in the suction side accommodation groove 163 and the suction port 161 is opened. Further, when the pressure difference between the pump chamber 20 and the suction passage 103 (= “pressure in the suction passage 103” − “pressure in the pump chamber 20”) is small or the pressure in the pump chamber 20 is higher than the pressure in the suction passage 103. The suction-side elastic piece 281 closes the suction port 161 in close contact with the inner peripheral surface of the cylinder by the elastic force generated by itself.

  A discharge valve 30 that opens and closes the discharge port 162 is disposed on the outer peripheral side of the cylinder 16. As shown in FIGS. 1 and 6 to 8, the discharge valve 30 is configured by a discharge-side elastic piece 301 formed by forming a metal plate into an arc shape, and is disposed along the outer peripheral surface of the cylinder 16. ing. At one end in the circumferential direction of the discharge-side elastic piece 301, a discharge-side protrusion 301a that is bent so as to protrude radially inward is provided.

  As shown in FIGS. 1, 9, and 10, an annular discharge side accommodation groove 165 is formed on the outer peripheral surface of the cylinder 16, and the discharge side elastic piece 301 is accommodated in the discharge side accommodation groove 165. In addition, a discharge port 162 is opened in the discharge side accommodation groove 165. A discharge-side insertion hole 166 is formed in the discharge-side receiving groove 165, and the discharge-side protrusion 301a is inserted into the discharge-side insertion hole 166.

  A part of the ejection-side elastic piece 301 contacts and separates from the bottom surface of the ejection-side receiving groove 165 to open and close the ejection port 162 and generate an elastic force in a direction to close the ejection port 162. More specifically, when the pressure in the pump chamber 20 is higher than the pressure in the discharge passage 104 by a predetermined value or more, the discharge-side elastic piece 301 is elastically deformed against the elastic force generated by itself and faces the discharge port 162. The vicinity of the part to be separated is separated from the cylinder outer peripheral surface in the discharge side accommodation groove 165 to open the discharge port 162. Further, when the pressure difference between the pump chamber 20 and the discharge passage 104 (= “pressure of the pump chamber 20” − “pressure of the discharge passage 104”) is small or the pressure of the pump chamber 20 is lower than the pressure of the discharge passage 104. The discharge-side elastic piece 301 closes the discharge port 162 by being in close contact with the cylinder outer peripheral surface by the elastic force generated by itself.

  A slit 167 extending in the cylinder axial direction is formed in the discharge side accommodation groove 165. One end of the slit 167 communicates with the discharge port 162, and the other end of the slit 167 extends to a position where it is not closed by the discharge-side elastic piece 301. Therefore, the discharge passage 104 and the discharge port 162 are always in communication with each other through the slit 167.

  Next, the operation of the pump configured as described above will be described.

  When the cam 14 rotates together with the rotating shaft 12, the piston 18 reciprocates in the cylinder 16. In the suction stroke in which the piston 18 is pushed back toward the cam 14 by the return spring 22, the pressure in the pump chamber 20 becomes lower than the pressure in the suction passage 103, and the suction side elastic piece 281 is elastically deformed and the suction port 161. Is opened, and the brake fluid is sucked into the pump chamber 20 from the suction passage 103 through the suction port 161.

  On the other hand, in the discharge stroke in which the piston 18 is pushed out by the cam 14, the pressure in the pump chamber 20 becomes higher than the pressure in the discharge passage 104, the discharge-side elastic piece 301 is elastically deformed, and the discharge port 162 is opened. The brake fluid whose pressure has been increased is discharged to the discharge passage 104 through the discharge port 162.

  According to this embodiment, the following effects can be obtained.

  First, by using the suction valve 28 of the present embodiment, the groove on the outer peripheral surface of the piston in the conventional piston pump can be made unnecessary, and the length of the suction valve 28 in the pump axial direction can be shortened. Therefore, together, they can shorten the length of the piston pump in the pump axial direction.

  Moreover, since the discharge valve 30 can be arrange | positioned at the outer peripheral side of the cylinder 16 by using the discharge valve 30 of this embodiment, the pump axial direction length of a piston pump can further be shortened.

  Furthermore, since the suction valve 28 is disposed on the inner peripheral side of the cylinder 16, the area occupied by the piston pump in the pump radial direction can be reduced.

  Furthermore, since the suction side elastic piece 281 constituting the suction valve 28 has a function of opening and closing the suction port 161, a valve body is unnecessary, and the configuration of the suction valve 28 can be simplified.

  Further, the suction valve 28 can be positioned in the pump axial direction by accommodating the suction valve 28 in the suction side accommodation groove 163 of the cylinder 16.

  Further, the engagement of the suction side insertion hole 164 of the cylinder 16 and the suction side protrusion 281a of the suction valve 28 enables positioning of the suction valve 28 in the circumferential direction of the pump.

  Furthermore, the discharge valve 30 can be positioned in the circumferential direction of the pump by engaging the discharge side insertion hole 166 of the cylinder 16 with the discharge side protrusion 301 a of the discharge valve 30.

  Further, by using the seal member 24 of the present embodiment, it is not necessary to form a groove for accommodating the seal member in the piston, and the shape of the piston 18 can be simplified.

  Furthermore, since the discharge passage 104 and the discharge port 162 are always in communication via the slit 167, it is possible to prevent the pump chamber 20 from being left in a negative pressure state while the pump is stopped.

(Second Embodiment)
A second embodiment of the present invention will be described. This embodiment differs from the first embodiment in the configuration of the intake valve 28 and the discharge valve 30. Since other aspects are the same as those in the first embodiment, only different parts will be described.

  As shown in FIG. 11, the suction valve 28 includes a suction-side elastic piece 281 formed of a metal plate in an arc shape, and a suction-side valve body 282 that opens and closes the suction port 161 in contact with and away from the inner peripheral surface of the cylinder 16. It is composed of. The suction side valve body 282 is made of resin or rubber and is formed in a disc shape. The suction side valve body 282 is biased by the suction side elastic piece 281 in a direction to close the suction port 161.

  A cylinder-side suction side accommodation hole 168 is formed in the suction side accommodation groove 163 of the cylinder 16, and the suction side valve body 282 is accommodated in the suction side accommodation hole 168, and the suction side accommodation hole is provided. A suction port 161 is opened at 168.

  When the pressure in the pump chamber 20 is lower than the pressure in the suction passage 103 by a predetermined value or more, the suction side elastic piece 281 is elastically deformed, and the suction side valve body 282 is moved from the cylinder inner peripheral surface in the suction side accommodation hole 168. Open the inlet 161 away. Further, when the pressure difference between the pump chamber 20 and the suction passage 103 (= “pressure in the suction passage 103” − “pressure in the pump chamber 20”) is small or the pressure in the pump chamber 20 is higher than the pressure in the suction passage 103. The suction side elastic piece 281 is biased so that the suction side valve body 282 comes into close contact with the inner peripheral surface of the cylinder and closes the suction port 161.

  The discharge valve 30 includes a discharge side elastic piece 301 formed of a metal plate in an arc shape and a discharge side valve body 302 that opens and closes the discharge port 162 in contact with and away from the outer peripheral surface of the cylinder 16. The discharge side valve body 302 is made of resin or rubber and is formed in a disc shape. The discharge-side valve element 302 is urged by the discharge-side elastic piece 301 in the direction in which the discharge port 162 is closed.

  A discharge side accommodation hole 169 having a cylindrical hole shape is formed in the discharge side accommodation groove 165 of the cylinder 16, and the discharge side valve body 302 is accommodated in the discharge side accommodation hole 169, and the discharge side accommodation hole is provided. A discharge port 162 is opened at 169.

  When the pressure in the pump chamber 20 is higher than the pressure in the discharge passage 104 by a predetermined value or more, the discharge side elastic piece 301 is elastically deformed, and the discharge side valve body 302 is separated from the cylinder outer peripheral surface in the discharge side accommodation hole 169. Then, the discharge port 162 is opened. Further, when the pressure difference between the pump chamber 20 and the discharge passage 104 (= “pressure of the pump chamber 20” − “pressure of the discharge passage 104”) is small or the pressure of the pump chamber 20 is lower than the pressure of the discharge passage 104. The discharge side elastic body 301 is biased to cause the discharge side valve body 302 to be in close contact with the outer peripheral surface of the cylinder and close the discharge port 162.

(Third embodiment)
A third embodiment of the present invention will be described. In the present embodiment, the configuration of the intake valve 28 is different from that of the first embodiment. Since other aspects are the same as those in the first embodiment, only different parts will be described.

  As shown in FIGS. 12 and 13, the suction valve 28 is configured by a suction-side elastic piece 281 in which a wire made of metal and having a circular cross section is formed into an arc shape. At one end in the circumferential direction of the suction side elastic piece 281, a suction side protrusion 281 a that is bent so as to protrude radially outward is provided.

  A suction side seat groove 170 having a semicircular or arcuate cross section is formed in the suction side accommodation groove 163 of the cylinder 16 along the circumferential direction of the cylinder. 281 is accommodated, and a suction port 161 is opened in the suction side sheet groove 170. Three suction ports 161 are formed along the circumferential direction of the cylinder.

  Note that the suction side insertion hole 164 can be processed by further advancing the drill after processing the suction port 161 when the suction port 161 at a position shifted by 180 ° in the circumferential direction of the cylinder is processed by, for example, a drill.

  A part of the suction side elastic piece 281 contacts and separates from the inner peripheral surface of the cylinder in the suction side seat groove 170 to open and close the suction port 161 and generate an elastic force in a direction to close the suction port 161. More specifically, when the pressure in the pump chamber 20 is lower than the pressure in the suction passage 103 by a predetermined value or more, the suction side elastic piece 281 is elastically deformed against the elastic force generated by itself and faces the suction port 161. The vicinity of the part to be separated is separated from the inner peripheral surface of the cylinder and the suction port 161 is opened. Further, when the pressure difference between the pump chamber 20 and the suction passage 103 (= “pressure in the suction passage 103” − “pressure in the pump chamber 20”) is small or the pressure in the pump chamber 20 is higher than the pressure in the suction passage 103. The suction-side elastic piece 281 closes the suction port 161 in close contact with the inner peripheral surface of the cylinder by the elastic force generated by itself.

  The discharge valve 30 can also have the same configuration as the suction valve 28 of the present embodiment. That is, the discharge valve 30 can be configured by a discharge-side elastic piece in which a metal wire having a circular cross section is formed into an arc shape.

  Further, this embodiment can be combined with the first and second embodiments.

(Other embodiments)
In each said embodiment, although this invention was applied to the pump of the brake device for vehicles, this invention is applicable also to the pump of another use.

16 cylinder 18 piston 20 pump chamber 28 suction valve 30 discharge valve 103 suction passage 104 discharge passage 161 suction port 162 discharge port 281 suction side elastic piece

Claims (8)

A cylindrical port having a suction port (161) for introducing a fluid from an external suction passage (103) into the pump chamber (20) and a discharge port (162) for discharging the fluid in the pump chamber to an external discharge passage (104). A cylinder (16);
A piston (18) that is slidably inserted into the cylinder, defines the pump chamber together with the cylinder, and changes the volume of the pump chamber by reciprocation;
A suction valve (28) for opening and closing the suction port;
A discharge valve (30) for opening and closing the discharge port,
One end of the suction port opens to the inner peripheral surface of the cylinder,
The suction valve has a suction side elastic piece (281) that generates an elastic force in a direction to close the suction port, and the suction side elastic piece is formed in an arc shape along the inner peripheral surface of the cylinder. A piston pump characterized by comprising a plate material or a wire material arranged.   2. The piston pump according to claim 1, wherein the suction valve is configured such that the suction side elastic piece contacts and separates from an inner peripheral surface of the cylinder to open and close the suction port.   2. The piston according to claim 1, wherein the suction valve includes a suction side valve body (282) that opens and closes the suction port in contact with and away from an inner peripheral surface of the cylinder, and the suction side elastic piece. pump.   The piston pump according to any one of claims 1 to 3, wherein an annular suction side accommodation groove (163) for accommodating the suction valve is formed on an inner peripheral surface of the cylinder. The suction side elastic piece includes a suction side protrusion (281a),
The piston pump according to any one of claims 1 to 4, wherein a suction side insertion hole (164) into which the suction side protrusion is inserted is formed on an inner peripheral surface of the cylinder. One end of the discharge port opens to the outer peripheral surface of the cylinder,
The discharge valve has a discharge side elastic piece (301) that generates an elastic force in a direction to close the discharge port, and the discharge side elastic piece is formed in an arc shape along the outer peripheral surface of the cylinder. The piston pump according to any one of claims 1 to 5, wherein the piston pump comprises a plate member or a wire member to be disposed. A seal member (24) for preventing fluid in the pump chamber from leaking from the outer peripheral surface of the piston;
The piston pump according to any one of claims 1 to 6, wherein the seal member and the piston are configured to slide.   The piston pump according to claim 6, wherein a slit (167) that allows the discharge passage and the discharge port to always communicate with each other is formed on an outer peripheral surface of the cylinder.

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