Piston pump for brake system

Patent metadata

Field	Value
Publication number	US-12319255-B2
Application number	US-202117531502-A
Country	US
Kind code	B2
Filing date	Nov 19, 2021
Priority date	Dec 11, 2020
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

According to at least one aspect, the present disclosure provides a piston pump comprising: a piston unit configured to reciprocate by driving of a motor cam; a sleeve unit disposed to surround at least a part of the piston unit and having a space in which brake oil is stored; and a check valve unit facing the sleeve unit and discharging the brake oil to an outside of the sleeve unit when a pressure of the brake oil increases, wherein the piston unit includes a first piston having a first end in contact with the motor cam and reciprocating, a second piston having a first end coupled to a second end of the first piston and configured to press the brake oil, and a spring cap coupled to a second end of the second piston and disposed to accommodate an inlet spring therein.

First claim

What is claimed is:

1. A piston pump comprising:
a piston unit configured to reciprocate in a piston housing by driving of a motor cam;
a sleeve unit disposed to surround at least a part of the piston unit and having an accommodation space in which brake oil is stored; and
a check valve unit disposed to face the sleeve unit and configured to discharge the brake oil to an outside of the sleeve unit when a pressure of the brake oil stored in the accommodation space of the sleeve unit increases,
wherein the piston unit includes a first piston having a first end in contact with the motor cam and configured to reciprocate, a second piston having a first end coupled to a second end of the first piston and operating in conjunction with reciprocating movement of the first piston to press the brake oil stored in the accommodation space of the sleeve unit, and a spring cap coupled to a second end of the second piston and disposed to accommodate an inlet spring therein,
wherein the second piston includes:
a piston head unit having at least a part of which an outer diameter is a first diameter; and
a step unit having at least a part of which an outer diameter is a second diameter greater than the first diameter,
wherein the spring cap includes:
a piston coupling unit coupled to at least a part of the piston head unit;
a cap head unit disposed to accommodate the inlet spring, wherein an inside and an outside of the cap head unit are configured to fluidly communicate with each other;
a flange unit radially extending from an end-most portion of the spring cap; and
a slope unit extending between the piston coupling unit and the cap head unit and having an inner diameter which decreases in a direction from the piston coupling unit toward the cap head unit, and configured to stop the second piston by contacting an inner circumferential surface of the slope unit with the second piston when the second piston moves to press the brake oil,
wherein the piston unit includes a first sealing disposed between the flange unit and the step unit in an axial direction,
wherein the piston coupling unit is disposed between the cap head unit and the flange unit and is coupled to a circumferential surface of the piston head unit, and
wherein:
the first piston includes a first coupling unit coupled to at least a part of the second piston;
the second piston includes a second coupling unit disposed to surround the first coupling unit;
the first coupling unit and the second coupling unit are press-fitted to each other; and
an outer width of the first coupling unit varies in a radial direction such that at least a portion of the first coupling unit is spaced apart from the second coupling unit when coupled thereto.

2. The piston pump of claim 1 , wherein the inner diameter of at least a part of the cap head unit is a third diameter smaller than the first diameter.

3. The piston pump of claim 1 , wherein the piston head unit and the piston coupling unit are press-fitted to be coupled.

4. The piston pump of claim 1 , wherein the piston unit includes an inlet ball disposed between the second piston and the spring cap and pressed by the inlet spring in a direction toward the second piston.

5. The piston pump of claim 1 , further comprising:
a second sealing disposed between the piston housing and the first piston;
a backup ring disposed between the piston housing and the first piston and configured to support the first piston; and
a guide ring disposed between the piston housing and the first piston and configured to guide reciprocating movement of the first piston.

6. A piston pump comprising:
a piston unit configured to reciprocate in a piston housing by driving of a motor cam;
a sleeve unit disposed to surround at least a part of the piston unit, and having an accommodation space in which brake oil is stored; and
a check valve unit disposed to face the sleeve unit and configured to discharge the brake oil to an outside of the sleeve unit when a pressure of the brake oil stored the accommodation space of the sleeve unit increases,
wherein the piston unit includes a first piston having a first end in contact with the motor cam and configured to reciprocate, a second piston having a first end press-fitted and coupled to a second end of the first piston and operating in conjunction with reciprocating movement of the first piston to press the brake oil stored in the accommodation space of the sleeve unit, and a spring cap disposed to accommodate an inlet spring therein and coupled to a second end of the second piston,
wherein the second piston includes:
a piston head unit having at least a part of which an outer diameter is a first diameter; and
a step unit having at least a part of which an outer diameter is a second diameter greater than the first diameter,
wherein the spring cap includes:
a piston coupling unit coupled to at least a part of the piston head unit;
a cap head unit disposed to accommodate the inlet spring, wherein an inside and an outside of the cap head unit are configured to fluidly communicate with each other;
a flange unit radially extending from an end-most portion of the spring cap; and
a slope unit extending between the piston coupling unit and the cap head unit and having an inner diameter which decreases in a direction from the piston coupling unit toward the cap head unit, and configured to stop the second piston by contacting an inner circumferential surface of the slope unit with the second piston when the second piston moves to press the brake oil,
wherein the piston unit includes a first sealing disposed between the flange unit and the step unit in an axial direction,
wherein the piston coupling unit is disposed between the cap head unit and the flange unit and is coupled to a circumferential surface of the piston head unit, and
wherein:
the first piston includes a first coupling unit coupled to at least a part of the second piston;
the second piston includes a second coupling unit disposed to surround the first coupling unit;
the first coupling unit and the second coupling unit are press-fitted to each other; and
an outer width of the first coupling unit varies in a radial direction such that at least a portion of the first coupling unit is spaced apart from the second coupling unit when coupled thereto.

7. The piston pump of claim 6 , wherein the first end of the first piston is punch-processed in a direction perpendicular to a longitudinal axis direction so that the brake oil is flowable.

8. The piston pump of claim 5 , wherein the backup ring is disposed between the second sealing and the guide ring.

Assignees

• Hyundai Mobis Co Ltd

Inventors

• Choi Young Chang

Classifications

• F04B53/12

  arranged in or on pistons · CPC title

• F16D2125/023

  Pumps · CPC title

• B60T2270/10

  ABS control systems · CPC title

• F16K15/044

  spring-loaded · CPC title

• F16D65/22

  adapted for pressing members apart {, e.g. for drum brakes} · CPC title