KR20160067423A - Piston assembly and braking system having the same - Google Patents

Abstract

The present invention provides a piston assembly which comprises: a first piston wherein a first oil flow path is formed; a second piston coupled to the first piston for an oil stay space to be interconnected to the first oil flow path, wherein a second oil flow path is formed, and the oil stay space interconnected to the second oil flow path is formed; an inlet ball opening and closing an exit of the first oil flow path; and an elastic member arranged in the oil stay space to support the inlet ball, thereby removing a plastic cage wherein deformation possibility is high in a high temperature environment, and reducing the whole volume of a pump.

Description

PISTON ASSEMBLY AND BRAKING SYSTEM HAVING THE SAME [

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston assembly and a pump of a braking device including the same, and more particularly, to a piston assembly for supplying braking hydraulic pressure to a hydraulic braking device and a pump of the braking device.

The brake system of the vehicle basically implements the braking function of the vehicle, and in recent years, the braking system effectively prevents the slip phenomenon of the vehicle to obtain a strong and stable braking force. The anti-lock brake system Anti-Lock Brake System (ABS), a brake traction control system (BTCS) that prevents slippage of the drive wheels during sudden acceleration or rapid acceleration of the vehicle, anti-lock brake system and traction control, And a vehicle dynamic control system (VDC) for stably maintaining the running state of the vehicle.

The brake system includes a plurality of solenoid valves for controlling the braking hydraulic pressure transmitted to the hydraulic brake side mounted on the wheels of the vehicle, a pair of low pressure accumulators for temporarily storing the oil that has escaped from the hydraulic brakes, A pump for forcibly pumping the solenoid valve and an ECU for controlling the driving of the solenoid valve and the motor, and these components are compactly built in the modulator block. Therefore, the oil of the low pressure accumulator is transmitted to the hydraulic brake or the master cylinder assembly side by driving the pump. The pump is driven by a motor, and as a pump structure, Korean Patent Laid-open Nos. 10-2003-0067839 and 10-2008-0093717 disclose such a pump.

1 is a view showing a pump of a conventional braking device.

The pump 1 may include a sleeve assembly 20 and a piston assembly 30 disposed within the pump housing 10. The pump 1 supplies the master cylinder brake oil to the wheel cylinders in the same manner as the arrow indicated by A in Fig.

The sleeve assembly 20 includes a cap portion 21 and a sleeve 23 that forms an oil passage 22 through a gap between the cap portion 21 and the cap portion 21 and forms a compression chamber 23a therein . An outlet ball 24 for opening and closing the outlet 23b of the sleeve 23 and a spring 25 disposed on the cap 21 for supporting the outlet ball 24.

Next, the piston assembly 30 includes a piston 31 disposed in the compression chamber 23a of the sleeve 23, a spring (not shown) provided in the compression chamber 23a of the sleeve 23 to support the piston 31 32). An oil passage 31a may be formed in the piston 31 and an inlet ball 33 for opening and closing the outlet 31b and a spring 34 for supporting the inlet ball 33 may be disposed at the outlet 31b of the oil passage 31a .

Fig. 2 is a view showing the operating state of the pump in the suction stroke, and Fig. 3 is a view showing the operating state of the pump in the compression stroke.

2, when the piston 31 is retracted by the cam 40, the master cylinder brake oil moves to the compression chamber 23a of the sleeve 23 through the oil passage 31a. At this time, when the oil flows into the oil passage 31a, the inlet 31b of the oil passage 31a is opened while the inlet ball 33 of FIG. 1 is pushed.

3, when the piston 31 is moved forward by the cam 40, the oil in the compression chamber 23a is moved toward the wheel cylinder via the outlet 23b and the oil passage 22 .

However, the configuration of the piston assembly 30 has the following problems.

First, manufacturing cost is increased because it is made up of many parts.

Second, if the plastic cage 35 accommodating the spring 34 supporting the inlet ball 33 is exposed for a long time under a high temperature condition, deformation may occur.

Third, since the plastic cage 35 is assembled to the tip end of the piston 31, the total volume of the pump 1 becomes large.

Accordingly, it is an object of the present invention to provide a braking device pump capable of reducing the number of parts, and more particularly, a braking device pump capable of removing a component having a high dimensional defect rate.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned here can be understood by those skilled in the art from the following description.

In order to achieve the above object, according to the present invention, there is provided an internal combustion engine comprising a first piston in which a first oil passage is formed, an oil retention space in which a second oil passage is formed and which communicates with the second oil passage, A second piston connected to the first oil passage so as to communicate with the first oil passage; an inlet ball for opening and closing the outlet of the first oil passage; and an elastic member disposed in the oil accommodation space and supporting the inlet ball To provide a piston assembly.

Preferably, the diameter of the first piston and the diameter of the second piston may be the same.

Preferably, the first piston and the second piston are axially coupled.

Preferably, the first oil passage and the second oil passage may be arranged to be aligned with each other in the axial direction of the first piston and the second piston.

Preferably, the first oil passage and the second oil passage may be arranged to be aligned with an axial center of the first piston and the second piston.

Preferably, the inlet direction and the outlet direction of the first oil passage may be formed perpendicular to each other.

Preferably, the oil ring is disposed along the outer circumferential surface of the second piston.

Preferably, the oil ring may be arranged in a double-row manner between the first oil ring and the second oil ring.

According to another aspect of the present invention, there is provided a piston assembly comprising a pump housing, a sleeve assembly disposed within the pump housing and connected to a wheel cylinder, and a piston assembly movably disposed within the sleeve assembly, A first piston having a first oil passage formed therein and an oil retention space in which a second oil passage is formed and communicated with the second oil passage is formed and the oil retention space communicates with the first oil passage, The present invention provides a pump for a braking device including a second piston coupled to a piston, an inlet ball for opening and closing an outlet of the first oil passage, and an elastic member disposed in the oil retention space for supporting the inlet ball .

According to one embodiment of the present invention, unlike the prior art in which the cage and the elastic member are disposed outside the piston tip. The inlet ball and the elastic member are formed inside the piston formed by the first piston and the second piston so that the oil retention space serves as a conventional cage so that the plastic cage having high possibility of being deformed in a high temperature environment is removed, Thereby providing an advantageous effect of reducing the volume.

1 is a view showing a pump of a conventional braking device,
2 is a view showing an operating state of the pump in the suction stroke,
3 is a view showing an operating state of the pump in the compression stroke,
Figure 4 illustrates a piston assembly according to one preferred embodiment of the present invention,
5 is a view showing an operating state of the piston assembly during oil inflow at a low pressure portion,
6 is a view showing a backward flow preventing operation state of the piston assembly when the oil flows in the high pressure portion.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In addition, the preferred embodiments of the present invention will be described below, but it is needless to say that the technical idea of the present invention is not limited thereto and can be variously modified by those skilled in the art.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

4 is a view showing a piston assembly according to a preferred embodiment of the present invention. Fig. 4 clearly illustrates only the main feature parts in order to clearly understand the present invention, and as a result various variations of the illustration are expected, and the scope of the present invention need not be limited to the specific shapes shown in the drawings .

Referring to FIG. 4, the pump according to an exemplary embodiment of the present invention may include a piston assembly 100 and a sleeve assembly 200 installed inside the pump housing. The present invention eliminates the conventional cage which has a large risk of deformation and which is disposed at the tip of the piston to increase the volume of the entire pump and prevents the first piston 110 of the piston assembly 100, And a second piston 120. The piston 120 has a technical characteristic that a piston is constituted.

The piston assembly 100 may include a first piston 110, a second piston 120, an inlet ball 130, and an elastic member 140.

First, a first oil passage 111 connected to the master cylinder A is formed in the first piston 110. The first oil passage 111 serves as a passage for transmitting the oil supplied from the master cylinder A to the second piston 120. The outlet 111a of the first oil passage 111 is located at the tip of the first piston 110 and may be disposed at the axis CL. The inlet 111b of the first oil passage 111 may be disposed on the outer circumferential surface. As a result, the first oil passage 111 can be bent in the radial direction from the axial center CL toward the outer peripheral surface.

A protrusion 113 may be formed around the outlet 111a of the first oil passage 111 so that the step 112 is formed at the tip of the first piston 110. [ This is a structure for enhancing the sealing performance with respect to the rear end of the second piston 120 and the oil retention space 122 of the second piston 120.

A second oil passage 121 is formed in the second piston 120 to supply the oil introduced from the first piston 110 to the wheel cylinder B. And the second oil passage 121 may be arranged so as to be aligned with the axis CL. An oil retention space 122 may be formed in the second piston 120. The oil retention space 122 may be hollow and formed inside the oil retention space 122 with the rear end of the second piston 120 being open. The outlet 111a of the first oil passage 111 and the inlet of the second oil passage 121 are formed to communicate with the oil retention space 122.

On the other hand, an oil ring 150 may be installed around the second piston 120. The oil ring 150 can be arranged in a double row in which the first oil ring 151 and the second oil ring 152 are arranged.

The rear end of the second piston 120 is axially aligned with respect to the axial center CL at the tip of the first piston 110. [ When the first piston (110) and the second piston (120) are engaged, the oil retention space (122) is closed by the tip of the first piston (110). That is, the rear end of the second piston 120 comes into contact with the step 112 at the tip of the first piston 110, and the protrusion 113 of the first piston 110 enters the oil staying space 122 .

The first piston 110 and the second piston 120 are coupled to each other to form a sealed oil reservoir space 122. The oil discharged from the outlet 111a of the first oil passage 111 flows into the oil So that the retention space 122 is filled.

The inlet ball 130 serves to open and close the outlet 111a of the first oil passage 111. [ The inlet ball 130 closes the outlet 111a while being pressed and supported by the elastic member 140 installed in the oil retention space 122 to receive the restoring force. The elastic member 140 may be formed to be disposed along the axial center CL and to be supported on the inner wall of the second piston 120 which forms the oil retention space 122 at either end. A protruding structure is formed on the inner wall of the second piston 120 adjacent to the inlet of the second oil passage 121 so that the elastic member 140 can be inserted and supported.

Unlike the prior art in which the cage and the elastic member are disposed outside the piston tip. The inlet ball 130 and the elastic member 140 are formed inside the piston formed by the first piston 110 and the second piston 120 and the oil staying space 122 is configured to serve as a conventional cage , The plastic cage, which is highly likely to deform in a high temperature environment, can be removed and reduced to the entire volume of the pump.

Below. The operation state of the pump of the braking device will be described with reference to Figs. 5 and 6. Fig.

FIG. 5 is a view showing an operation state of the piston assembly when the oil flows into the low-pressure section, and FIG. 6 is a diagram showing a state in which the piston assembly is prevented from flowing backward when the oil flows in the high-

5, when the piston 110 is moved backward by the rotation of the cam, the oil introduced into the first oil passage 111 in the low pressure region is discharged to the inlet ball 130 while overcoming the restoring force of the elastic member 140, So that the outlet 111a of the first oil passage 111 is opened. The oil discharged through the outlet 111a of the first oil passage 111 stays in the oil staying space 122.

6, when the oil flows into the second oil passage 121 in the high pressure region, the oil discharged into the second oil passage 121 pushes the inlet ball 130 out of the first oil passage 111, And closes the outlet 111a.

The piston assembly according to one preferred embodiment of the present invention and the pump of the braking device including the piston assembly have been described in detail with reference to the accompanying drawings.

It will be apparent to those skilled in the art that various modifications, substitutions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. will be. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are intended to illustrate and not to limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings . The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: Piston assembly
110: first piston
111: first oil passage
111a:
120: second piston
121: second oil passage
122: Oil retention space
130: Inlet ball
140: elastic member
150: Oiling
151: first oil ring
152: second oil ring

Claims (5)

A first piston having a first oil passage formed therein;
A second piston having a second oil passage formed therein and having an oil retention space communicated with the second oil passage and coupled to the first piston so that the oil retention space communicates with the first oil passage;
An inlet ball for opening and closing the outlet of the first oil passage;
And an elastic member disposed in the oil retention space for supporting the inlet ball
≪ / RTI > The method according to claim 1,
Wherein the first piston and the second piston are axially coupled. 3. The method of claim 2,
Wherein the first oil passage and the second oil passage are disposed so as to be aligned with each other in the axial direction of the first piston and the second piston. The method of claim 3,
Wherein the first oil passage and the second oil passage are disposed so as to be aligned with an axial center of the first piston and the second piston. Pump housing;
A sleeve assembly disposed within the pump housing and connected to the wheel cylinder;
A piston assembly movably disposed within the sleeve assembly,
Wherein the piston assembly has a first piston in which a first oil passage is formed and an oil retention space in which a second oil passage is formed and communicated with the second oil passage is formed inside and the oil retention space communicates with the first oil passage An inlet ball that opens and closes an outlet of the first oil passage; and an elastic member that is disposed in the oil retaining space and supports the inlet ball.

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