JP4200871B2 - Piston pump - Google Patents

Description

  The present invention relates to a piston pump, for example, a piston pump employed as a pump for a vehicle brake device.

This type of piston pump is disclosed in, for example, Patent Document 1 below, and forms a pump chamber in a cylinder hole of a cylinder member that is inserted and assembled into an inner hole of a pump housing having a suction port and a discharge port. A piston that increases or decreases the volume of the pump chamber by reciprocating in the axial direction, a suction valve that is provided on the piston and that opens when the volume of the pump chamber increases and closes when the volume decreases, and is provided on the discharge side of the pump chamber And a discharge valve that opens when the volume of the pump chamber decreases and closes when the volume of the pump chamber increases. The piston is reciprocated in the axial direction to increase or decrease the volume of the pump chamber. It is comprised so that a fluid may flow toward.
JP-T-2002-514712

  In the above-described conventional piston pump, the cylinder member is formed in a sleeve shape having a constant outer diameter, and this cylinder member is press-fitted into the inner hole of the pump housing. The sealing property between the holes is ensured. In such a piston pump, when the cylinder member is press-fitted into the inner hole of the pump housing, the tip of the cylinder member may be squeezed into the inner hole of the pump housing, and the sealing performance between the cylinder member and the inner hole of the pump housing In addition, there is a possibility that the cylinder member is deformed (buckled) due to excessive press-fitting load, and the cylinder hole that accommodates the piston so as to reciprocate in the axial direction may be deformed. Therefore, the present invention improves the assembling property when the cylinder member is press-fitted into the inner hole of the pump housing, ensures the sealing property between the cylinder member and the inner hole of the pump housing, and deforms the cylinder hole. Control is an issue.

The present invention increases or decreases the volume of the pump chamber by forming a pump chamber in a cylinder hole of a cylinder member that is inserted and assembled into an inner hole of a pump housing having a suction port and a discharge port, and reciprocating in the axial direction. A piston that is provided on the piston and opens when the volume of the pump chamber increases and closes when the volume decreases; and a discharge valve that is provided on the discharge side of the pump chamber and closes when the volume of the pump chamber decreases and closes when the volume increases A piston pump configured such that fluid flows from the suction port toward the discharge port by increasing or decreasing the volume of the pump chamber by reciprocating the piston in the axial direction. The insertion end of the cylinder member has a smaller diameter than the inner hole of the pump housing, and the pump housing is formed on the outer periphery of the cylinder member excluding the insertion end of the small diameter. The annular protrusion cross section has a smooth outer shape with a circular shape in the insertion direction of the portion in contact with the inner hole of managing integrally formed, of the pump housing at the outer peripheral portion of the annular projection It is characterized by being configured to be press-fitted into the hole.

In this piston pump, since the insertion side end of the cylinder member has a smaller diameter than the inner hole of the pump housing, when the cylinder member is press-fitted into the inner hole of the pump housing, the tip of the cylinder member is pumped. The inner hole of the housing is not casilled, and the annular protrusion formed integrally with the outer periphery of the cylinder member has a circular cross-sectional shape in the insertion direction of the portion in contact with the inner hole of the pump housing and is smooth. Since it has an outer shape, it is smoothly press-fitted into the inner hole of the pump housing at the outer periphery .

  For this reason, in this piston pump, the generation of galling between the cylinder member and the inner hole of the pump housing can be prevented, and the sealing performance between the cylinder member and the inner hole of the pump housing can be ensured. Further, it is possible to reduce the press-fitting load and suppress the deformation (buckling) of the cylinder member, and it is possible to suppress the deformation of the cylinder hole that accommodates the piston so as to reciprocate in the axial direction.

  In carrying out the present invention, the cylinder member may be a press-molded product, and the annular protrusion may be formed by expanding a part of the cylinder member in the radially outward direction. In this case, the cylinder member can be easily manufactured, and the cost of the cylinder member can be reduced.

  In carrying out the present invention, the annular protrusion may be formed outside the reciprocating range of the piston. In this case, even if the cylinder member is press-fitted into the inner hole of the pump housing, the cylinder hole of the cylinder member is unlikely to deform within the range in which the piston reciprocates. Therefore, it is possible to sufficiently secure the allowance for press-fitting and fitting the annular protrusion into the inner hole of the pump housing without impairing the reciprocating motion of the piston in the cylinder hole of the cylinder member. For this reason, it is possible to ensure good sealing performance between the cylinder member and the inner hole of the pump housing and to ensure good reciprocation of the piston in the cylinder hole of the cylinder member.

  In carrying out the present invention, the end of the cylinder member is provided with a bottom wall in which a valve hole and a valve seat of the discharge valve are formed, and the annular projecting portion is provided at a position close to the bottom wall. It is also possible to provide it. In this case, it is possible to ensure sufficient rigidity in the radial direction of the annular protrusion by the bottom wall of the cylinder member, and to the inside of the diameter of the annular protrusion press-fitted into the inner hole of the pump housing. It is possible to suppress the deformation, and it is possible to suppress a decrease in surface pressure (decrease in sealing performance) at the press-fitting fitting portion due to the deformation.

  In carrying out the present invention, a resin cylindrical case for supporting the filter is fitted and fixed to the outer periphery of the insertion side end of the cylinder member, and the cylindrical case is an inner hole of the pump housing. It is also possible to be fitted into the. In this case, when the cylinder member is press-fitted into the inner hole of the pump housing, the case functions as a guide and restricts tilting of the cylinder member in the pump housing. For this reason, the annular protrusion of the cylinder member is press-fitted and fitted into the inner hole of the pump housing.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a piston pump according to the present invention. In this piston pump, a cylinder member 13 and a piston 15 are incorporated into an inner hole 11c of a pump housing 11 having a suction port 11a and a discharge port 11b, and a suction valve V1. And a discharge valve V2.

The cylinder member 13 is a metal press-molded product, is formed in a bottomed cylindrical shape, has a cylinder hole 13a, and a bottom wall 13d in which a valve hole 13b of the discharge valve V2 and a valve seat 13c are formed. ing. The cylinder member 13 has an outer diameter smaller than that of the inner hole 11c of the pump housing 11, and has an annular protrusion 13e on the outer periphery closer to the bottom wall 13d than the center. The annular protrusion 13e is formed by expanding a part of the cylinder member 13 in the radially outward direction outside the reciprocating range of the piston 15, and in the insertion direction of the portion in contact with the inner hole 11c of the pump housing 11 . The cross-sectional shape is circular and has a smooth outer shape, and is press-fitted into the inner hole 11c of the pump housing 11 at the outer periphery.

  The cylinder member 13 is assembled with the piston 15, the guide ring 17, the seal ring 19, and the cylindrical case 21 in the inner hole 11 c of the pump housing 11, and is prevented from coming off by a cap 23. Also, in the cylinder hole 13a formed in the cylinder member 13, one end portion (right end portion in the drawing) of the piston 15 is assembled together with the seal member 27 and the suction valve V1, and a piston return spring 29 is assembled. .

  The piston 15 is fitted into the inner hole 11c of the pump housing 11 through the guide ring 17 and the seal ring 19 at the other end (the left end in the figure) so as to be liquid-tight and slidable in the axial direction. At the other end, the outer peripheral surface of the eccentric body 31 that is rotationally driven by an electric motor (not shown) is slidably engaged. Moreover, the piston 15 forms the pump chamber Ro in the cylinder hole 13a by the one end part and the sealing member 27 with which this was attached | subjected. The piston 15 reduces the volume of the pump chamber Ro when the eccentric body 31 is rotated in the axial direction against the biasing force of the piston return spring 29 due to the rotation of the eccentric body 31, and the axial direction by the biasing force of the piston return spring 29. The volume of the pump chamber Ro is increased when it is moved back to the position.

  Further, the piston 15 is formed with a communication hole 15a extending in the axial direction and two communication holes 15b extending in the radial direction, and an annular groove 15c is formed corresponding to each communication hole 15b. ing. The communication hole 15a opens toward the pump chamber Ro at one end that functions as a valve hole of the suction valve V1, and a valve seat 15a1 of the suction valve V1 is formed in the opening. Each communication hole 15b is formed at an intermediate portion of the piston 15, communicates with the other end of the communication hole 15a at the inner end, and communicates with the annular groove 15c at the outer end. The annular groove 15 c communicates with the suction port 11 a of the pump housing 11 through a filter 22 assembled integrally with the cylindrical case 21.

  The cylindrical case 21 is a resin molded product and is fitted into the inner hole 11c of the pump housing 11 in a state where the cylindrical case 21 is coaxially press-fitted to the outer periphery of the other end of the cylinder member 13 at one end. ing. Further, the cylindrical case 21 has a plurality of suction holes 21a formed in the middle portion in the axial direction, and a filter 22 is integrally assembled corresponding to the suction holes 21a. The filter 22 is a single object formed in a cylindrical shape.

  The seal member 27 is an annular seal member that is interposed between the cylinder member 13 and the piston 15 and seals between the cylinder member 13 and the piston 15. The seal member 27 is assembled in an attachment groove 15 d formed in the piston 15, and is integrated with the piston 15. Reciprocates. The piston return spring 29 is a compression coil spring, and is interposed between the cylinder member 13 and the piston 15 with a predetermined preliminary load. The piston 15, the seal member 27, the suction valve V <b> 1, etc. are attached to the eccentric body 31. It is energizing towards.

  The suction valve V <b> 1 is provided at the end of the piston 15 on the pump chamber side. The suction valve V <b> 1 is seated on and separated from a valve seat 15 a 1 formed on the piston 15, and between the ball valve body 33 and the spring retainer 35. A spring 37 is provided to bias the ball valve body 33 toward the valve seat 15a1 with a small load, and is configured to open when the volume of the pump chamber Ro increases and to close when the volume decreases. The spring retainer 35 is fixed to the piston 15 by a snap fit.

  The discharge valve V2 is provided at the discharge side end of the cylinder member 13, that is, the discharge side of the pump chamber Ro, and a ball valve body 41 that is seated on and separated from a valve seat 13c formed on the bottom wall 13d of the cylinder member 13. A spring 43 is provided between the ball valve body 41 and the cap 23 and urges the ball valve body 41 toward the valve seat 13c with a small load, and the volume is closed when the pump chamber Ro increases in volume. It is configured to open at times.

  In the piston pump of this embodiment configured as described above, the piston 15 is pivoted due to the cooperative action of the eccentric body 31 and the piston return spring 29 when the eccentric body 31 is rotationally driven by an electric motor (not shown). By reciprocating in the direction, the volume of the pump chamber Ro is increased / decreased, and the suction valve V1 and the discharge valve V2 function to cause fluid to flow from the suction port 11a toward the discharge port 11b.

By the way, in the piston pump of this embodiment, since the cylinder member 13 has a smaller diameter than the inner hole 11 c of the pump housing 11, when the cylinder member 13 is press-fitted into the inner hole 11 c of the pump housing 11, The tip of the member 13 does not sag in the inner hole 11 c of the pump housing 11, and the annular protrusion 13 e provided on the outer periphery of the cylinder member 13 is a cross section in the insertion direction of the portion in contact with the inner hole 11 c of the pump housing 11. Since the shape is circular and has a smooth outer shape, it is smoothly press-fitted into the inner hole 11c of the pump housing 11 at the outer peripheral portion of the annular protrusion 13e .

  For this reason, in this piston pump, generation | occurrence | production of the galling between the cylinder member 13 and the inner hole 11c of the pump housing 11 can be prevented, and the sealing performance between the cylinder member 13 and the inner hole 11c of the pump housing 11 is improved. Can be secured. Further, it is possible to reduce the press-fitting load and suppress the deformation (buckling) of the cylinder member 13, and it is possible to suppress the deformation of the cylinder hole 13a that accommodates the piston 15 so as to reciprocate in the axial direction. It is.

  Further, in this piston pump, the cylinder member 13 is a press-molded product, and the annular projecting portion 13e is formed by expanding a part of the cylinder member 13 in the radially outward direction. For this reason, the cylinder member 13 can be manufactured easily, and the cost of the cylinder member 13 can be reduced.

  Moreover, in this piston pump, the annular protrusion 13e is formed outside the reciprocating range of the piston 15. For this reason, even if the cylinder member 13 is press-fitted into the inner hole 11 c of the pump housing 11, the cylinder hole 13 a of the cylinder member 13 is hardly deformed within the range in which the piston 15 reciprocates. Therefore, it is possible to sufficiently secure the allowance for press-fitting the annular protrusion 13e into the inner hole 11c of the pump housing 11 without impairing the reciprocating motion of the piston 15 in the cylinder hole 13a of the cylinder member 13. For this reason, it is possible to ensure a good sealing property between the cylinder member 13 and the inner hole 11c of the pump housing 11, and to ensure a good reciprocation of the piston 15 in the cylinder hole 13a of the cylinder member 13. .

  Further, in this piston pump, a bottom wall 13d in which the valve hole 13b of the discharge valve V2 and the valve seat 13c are formed is provided at the end of the cylinder member 13, and the ring protrudes at a position close to the bottom wall 13d. A portion 13e is formed. For this reason, the rigidity in the radial direction of the annular protrusion 13e can be sufficiently secured by the bottom wall 13d of the cylinder member 13, and the annular protrusion 13e press-fitted into the inner hole 11c of the pump housing 11 can be secured. It is possible to suppress the inward deformation, and it is possible to suppress a decrease in surface pressure (decrease in sealing performance) at the press-fitting portion due to the deformation.

  In this piston pump, a resin-made cylindrical case 21 that supports the filter 22 is fitted and fixed to the outer periphery of the insertion side end of the cylinder member 13, and the cylindrical case 21 is fixed to the pump housing 11. It is fitted in the inner hole 11c. For this reason, when the cylinder member 13 is press-fitted into the inner hole 11 c of the pump housing 11, the cylindrical case 21 functions as a guide and restricts the tilt of the cylinder member 13 in the pump housing 11. For this reason, the annular projecting portion 13 e of the cylinder member 13 is press-fitted and fitted into the inner hole 11 c of the pump housing 11.

  In the embodiment described above, the embodiment in which the piston pump is a general piston pump has been described, but the same applies to the case where the piston pump is a self-priming pump of the type disclosed in Japanese Patent No. 3278882. Can be implemented.

It is a whole lineblock diagram showing one embodiment of a piston pump by the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Pump housing, 11a ... Inlet port, 11b ... Discharge port, 11c ... Inner hole, 13 ... Cylinder member, 13a ... Cylinder hole, 13b ... Valve hole, 13c ... Valve seat, 13d ... Bottom wall, 13e ... Annular protrusion , 15 ... piston, 21 ..., cylindrical case, 22 ... filter, V1 ... suction valve, V2 ... discharge valve, Ro ... pump chamber

Claims (5)

A pump chamber (Ro) is formed in a cylinder hole (13a) of a cylinder member (13) to be inserted and assembled into an inner hole (11c) of a pump housing (11) having a suction port (11a) and a discharge port (11b). A piston (15) that increases or decreases the volume of the pump chamber (Ro) by being reciprocated in the axial direction, and is provided when the volume of the pump chamber (Ro) increases when the volume of the pump chamber (Ro) increases. A suction valve (V1) that closes, and a discharge valve (V2) that is provided on the discharge side of the pump chamber (Ro) and opens when the volume of the pump chamber (Ro) decreases, and closes when the volume increases. 15) A piston that is configured so that fluid flows from the suction port (11a) toward the discharge port (11b) by reciprocating in the axial direction to increase or decrease the volume of the pump chamber (Ro). In the pump, the insertion side end of the cylinder member (13) has a smaller diameter than the inner hole (11c) of the pump housing, and the cylinder member (13) excluding the small diameter insertion side end has an outer periphery on the outer periphery of the cylinder member (13). An annular protrusion (13e) having a smooth outer shape with a circular cross-sectional shape in the insertion direction of a portion in contact with the inner hole (11c) of the pump housing (11) is integrally formed. A piston pump characterized in that the outer periphery of (13e) is press-fitted into the inner hole (11c) of the pump housing.   2. The piston pump according to claim 1, wherein the cylinder member is a press-molded product, and the annular projecting portion is formed by bulging a part of the cylinder member in a radially outward direction. Piston pump.   3. The piston pump according to claim 1, wherein the annular projecting portion is formed outside a reciprocating range of the piston. 4.   4. The piston pump according to claim 3, wherein a bottom wall formed with a valve hole and a valve seat of the discharge valve is provided at an end of the cylinder member, and the annular protrusion is located at a position close to the bottom wall. Piston pump characterized by having a portion. 5. The piston pump according to claim 1, wherein a resin-made cylindrical case that supports a filter is fitted and fixed to an outer periphery of an insertion side end of the cylinder member. A piston pump characterized in that a cylindrical case is fitted in an inner hole of the pump housing.

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