Electronically controlled internal damper

Abstract

Electronically controlled internal damper with: a control piston rod (500) which is formed in such a way that it has a stepped shape in a lower end section of a piston rod (700) which moves back and forth in a cylinder; a valve unit comprising: a main piston (100) having a central section through which the control piston rod (500) extends, and which divides the cylinder into an upper cylinder chamber (U) and a lower cylinder chamber (D) and in which a compression stage channel (102) and a rebound stage channel (101) are arranged alternately; a compression stage holder (200) arranged above the main piston (100); a rebound stage holder (400) arranged below the main piston (100); a first housing (310) arranged above the compression stage holder (200) to form a first pilot chamber (311) therein, and which has an open bottom; and a second housing (320) arranged below the rebound stage holder (400) to form a second pilot chamber (322) therein, and which has an open top; a driven control piston (600) which moves back and forth along a guide channel (510) that penetrates a central section of the control piston rod (500); and a damping unit (900) provided on an outer circumferential surface of the driven control piston (600) and the control piston rod (500) to allow a working fluid to flow to the inside and outside of the control piston rod (500) through the guide channel (510) during a compression stroke or a rebound stroke, forming a first bypass channel (911) in an upper section of the control piston rod (500) during the compression stroke in a hard mode, and forming a second bypass channel (916) in a lower section of the control piston rod (500) during the rebound stroke in the hard mode, a third bypass channel (913) during the compression stroke in a soft mode, and a fourth bypass channel (914) during the rebound stroke in the soft mode.

Description

CROSS-REFERENCE TO A RELATED PATENT APPLICATION

[0001] This application claims priority to Korean patent application KR 10 2016 0 094 750 A, filed on February 2, 2015, with the Korean Intellectual Property Office, which is hereby incorporated by reference in its entirety. BACKGROUND OF THE INVENTIONField of the invention

[0002] The present invention relates to an electronically controlled internal damper, and more particularly to an electronically controlled internal damper capable of improving ride comfort by reducing a low-speed damping force of a soft mode without increasing the sizes of a driven spool and a spool rod. Description of the state of the art

[0003] In most conventional electronically controlled or controlled internal dampers, a bypass channel is located only on one side of the rebound stage.

[0004] In such electronically controlled internal dampers, as a passage area of ​​a cylinder becomes larger, it is difficult to reduce a low-speed damping force of a soft mode during a rebound stroke.

[0005] To solve this problem, it may be considered to increase the outer diameter of a spool to open a port in a split manner. However, such a design modification would result in an increase in the overall valve size or a reduction in the disc size, creating an adverse effect in a medium-speed section or a high-speed section. LIST OF CITED DOCUMENTS PATENT LITERATURE (Patent Literature 1) Korean Patent Registration KR 10 0 854 598 B1 (Patent Literature 2) Japanese Patent Application Laid-Open JP H07- 332 425 A

[0006] US 2003 / 0 132 073 A1 describes a piston with a connected piston rod, which is slidably mounted in a cylinder in which a hydraulic fluid is sealably contained. A pilot valve of a damping force control mechanism is formed by a pressure control valve with a valve seat, a valve body, and a pressure-receiving area. A pilot valve of another damping force control mechanism is formed by a flow control valve with a coil. A spool comprising the valve body of the pressure control valve and the piston of the flow control valve is actuated by a proportional solenoid to thereby control a damping force for an extension stroke and a damping force for a compression stroke. OVERVIEW OF THE INVENTION

[0007] The present invention has been created in an effort to solve the above-mentioned problems, and is directed to providing an electronically controlled internal damper capable of improving ride comfort by reducing a low-speed damping force of a soft mode in a driven spool and a spool rod having the same size.

[0008] In accordance with the present invention, there is provided an electronically controlled internal damper having the features defined in independent claim 1.

[0009] Advantageous further training results from the dependent subclaims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a conceptual cross-sectional diagram illustrating an overall configuration of an electronically controlled internal damper in accordance with an embodiment of the present invention. Fig. 2 is a perspective view illustrating a structure of a guide assembly formed in a driven spool of a damper unit, which is a main part of the electronically controlled internal damper, in accordance with the embodiment of the present invention. Fig. 3 is a conceptual cross-sectional diagram illustrating a flow of a working fluid during a rebound stroke of the electronically controlled internal damper according to the embodiment of the present invention. Fig. 4 is a conceptual cross-sectional diagram illustrating a flow of a working fluid during a compression stroke of the electronically controlled internal damper in accordance with the embodiment of the present invention. Fig. 5 is an enlarged partial perspective view of a driven control piston in accordance with another embodiment of the present invention. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0010] The advantages and features of the present invention, as well as methods for achieving the same, will become more apparent from the following embodiments described in detail in conjunction with the accompanying drawings.

[0011] But the present invention is not limited to the following embodiments, but may be embodied in various forms.

[0012] These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0013] The scope of the present invention is defined by the appended claims.

[0014] Therefore, in some embodiments, detailed descriptions of well-known elements, operations, and technologies are omitted for simplicity and clarity.

[0015] Throughout the disclosure, like reference numerals refer to like elements. The terminology used herein is intended to describe particular embodiments only and is not intended to limit the present invention.

[0016] Throughout this patent specification, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It will be understood that terms such as "comprise," "comprise," "include," and "have," when used herein, specify the presence of stated elements and acts or operations, but do not preclude the presence or addition of one or more other elements and one or more other acts or operations.

[0017] Unless otherwise defined, all terms, including technical and scientific terms, are used herein to have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs.

[0018] It will further be understood that terms such as those defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant subject matter and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0019] Now, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0020] Fig. 1 is a conceptual cross-sectional diagram illustrating an overall configuration of an electronically controlled internal damper in accordance with an embodiment of the present invention, and Fig. 2 is a perspective view illustrating a structure of a guide assembly formed in a driven spool of a damper unit, which is a main part of the electronically controlled internal damper, in accordance with the embodiment of the present invention.

[0021] As illustrated, a valve unit is attached to a spool rod 500 in which a driven spool 600 reciprocates, and a damping unit 900 is provided on an outer peripheral surface of the driven spool 600 and the spool rod 500.

[0022] The control piston rod 500 is formed to have a stepped shape in a lower end portion of a piston rod 700 that reciprocates within a cylinder (not illustrated).

[0023] The valve unit comprises a main piston 100 having a central section through which the control piston rod 500 extends. The main piston 100 divides the cylinder into an upper cylinder chamber U and a lower cylinder chamber D. A compression stage channel 102 and a rebound stage channel 101 are arranged alternately in the main piston 100.

[0024] The valve unit has a pressure stage holder 200 which is arranged above the main piston 100.

[0025] The valve unit has a rebound stage holder 400 which is arranged below the main piston 100.

[0026] The valve unit includes a first housing 310 disposed above the pressure stage holder 200 to form a first pilot chamber 311 therein and having an open bottom.

[0027] In addition, the valve unit includes a second housing 320 disposed below the rebound bracket 400 to form a second pilot chamber 322 therein and having an open top.

[0028] The driven control piston 600 moves back and forth along a guide channel 510 which penetrates a central portion of the control piston rod 500.

[0029] In addition, the damping unit 900 is provided on the outer peripheral surface of the driven spool 600 and the spool rod 500 to allow a working fluid to flow to the inside and the outside of the spool rod 500 through the guide channel during the compression stroke or the rebound stroke.

[0030] The damping unit 900 forms a bypass passage in an upper portion thereof during the compression stroke in a hard mode or a soft mode and forms a bypass passage in a lower portion thereof during the rebound stroke in the hard mode or the soft mode.

[0031] In addition to the embodiment described above, the present invention can also be applied to the following various embodiments.

[0032] In general, in the structure in which the compression holder 200 and the rebound holder 400 are respectively arranged symmetrically in the upper portion and the lower portion of the main piston 100, an inverted structure is formed when the flow of the working fluid is allowed by opening the passage in the driven control piston 600 in a divided manner.

[0033] This means that if the rebound side is soft, the compression side becomes hard. Therefore, the existing channel is useless.

[0034] Furthermore, when a flow rate of a working fluid bypassed via the driven spool 600 is increased to reduce a low-speed damping force, a flow force of the driven spool 600 proportional to the square of the flow rate is generated. As a result, a damping force is abnormally increased in a high-speed section of the soft mode.

[0035] Therefore, to solve these problems, the bypass passage formed between the control piston rod 500 and the driven control piston 600 during the compression stroke or the rebound stroke in the soft mode is provided between the bypass passages formed between the control piston rod 500 and the driven control piston 600 during the compression stroke or the rebound stroke in the hard mode.

[0036] In addition, the bypass passage formed between the control piston rod 500 and the driven control piston 600 during the compression stroke in the hard mode is provided above the bypass passage formed between the control piston rod 500 and the driven control piston 600 during the compression stroke in the soft mode.

[0037] That is, the bypass passage formed between the control piston rod 500 and the driven control piston 600 during the rebound stroke in the soft mode is provided above the bypass passages formed between the control piston rod 500 and the driven control piston 600 during the rebound stroke in the hard mode.

[0038] As can be seen, the damping unit 900 has a communication assembly 910 and a guide assembly 920.

[0039] The communication arrangement 910 is provided in the control piston rod 500 such that the first pilot chamber 311 of the first housing 310, the compression stage holder 200, the main piston 100, the rebound stage holder 400 and the second pilot chamber 322 of the second housing 320 communicate with the guide channel 510 from the upper side.

[0040] The guide assembly 920 is provided along the outer peripheral surface of the driven spool 600 and allows the flow of the working fluid from the upper and lower sides of the driven spool 600 through the communication assembly 910 according to the compression stroke or the rebound stroke in the hard mode or the soft mode.

[0041] The communication arrangement 910 has a channel 911 for a hard pressure stage, which communicates with the first pilot chamber 311 and is formed perpendicular to the guide channel 510.

[0042] The communication arrangement 910 has a first inlet channel 912 formed perpendicular to the guide channel 510 below the channel 911 for a hard compression stage and communicating with the first pilot chamber 311 through the central channel of the compression stage holder 200.

[0043] The communication arrangement 910 has a channel 913 for a soft compression stage, which is formed perpendicular to the guide channel 510 below the first inlet channel 912 and communicates with the upper side of the middle section of the main piston 100.

[0044] The communication arrangement 910 has a soft rebound channel 914 formed perpendicular to the guide channel 510 below the soft compression channel 913 and communicating with the lower side of the middle portion of the main piston 100.

[0045] The communication arrangement 910 has a second inlet channel 915 formed perpendicular to the guide channel 510 below the soft rebound channel 914 and communicating with the second pilot chamber 322 through the central channel of the rebound holder 400.

[0046] In addition, the communication arrangement 910 has a channel 916 for a hard rebound stage, which is formed perpendicular to the guide channel 510 below the second inlet channel 915 and communicates with the second pilot chamber 322.

[0047] Therefore, the guide arrangement 920, which will be described below, allows the flow of the working fluid through the passage 911 for a hard compression stage, the passage 913 for a soft compression stage, the passage 914 for a soft rebound stage and the passage 916 for a hard rebound stage.

[0048] With reference to Fig. 2, the guide assembly 920 specifically includes a guide groove 921 for a hard compression stage, the guide groove 921 being upwardly recessed at a lower edge of a first portion 621 having a large diameter constituting the driven control piston 600, formed in an upper portion of a driven body 610 having an outer diameter smaller than an inner diameter of the guide channel 510, integrated with the driven body 610, contacting an inner circumferential surface of the guide channel 510, and reciprocating therealong.

[0049] The guide assembly 920 includes a guide groove 922 for a soft compression stage, the guide groove 922 being recessed downwardly at an upper edge of a second large-diameter portion 622 formed on the outer peripheral surface of the driven body 610, integrated with the driven body 610, disposed below the first large-diameter portion 621, contacting the inner peripheral surface of the guide channel 510, and reciprocating therealong.

[0050] The guide assembly 920 includes a guide groove 923 for a soft rebound stage, the guide groove 923 being downwardly recessed at an upper edge of a third large-diameter portion 623 formed on the outer peripheral surface of the driven body 610, integrated with the driven body 610, disposed below the second large-diameter portion 622, contacting the inner peripheral surface of the guide channel 510, and reciprocating therealong.

[0051] In addition, the guide assembly 920 has a guide groove 924 for a hard rebound stage, the guide groove 924 being recessed upwardly on a lower wheel of the third section 623, which has a large diameter.

[0052] Therefore, the communication arrangement 910 allows the flow of the working fluid through the guide groove 921 for a hard compression stage, the guide groove 922 for a soft compression stage, the guide groove 923 for a soft rebound stage and the guide groove 924 for a hard rebound stage.

[0053] A volume formed by the guide groove 922 for a soft compression stage and the guide groove 923 for a soft rebound stage is larger than a volume formed by the guide groove 921 for a hard compression stage and the guide groove 924 for a hard rebound stage.

[0054] Compared with the conventional electronically controlled internal damper, the bypass flow rate is increased and the degree of freedom of reduction in the low-speed damping force in the soft mode is increased.

[0055] In addition, as in Fig. 5, boundary lines of a guide groove 922' for a soft compression stage and a guide groove 923' for a soft rebound stage have approximately a shape of a curly bracket "{".

[0056] In addition, a first length L1 between the guide groove 921 for a hard compression stage and the guide groove 922 for a soft compression stage may be greater than a second distance L2 between the guide groove 923 for a soft rebound stage and the guide groove 924 for a hard rebound stage.

[0057] The flow of the working fluid during the rebound stroke or the compression stroke using the electronically controlled internal damper in accordance with the embodiment of the present invention will be described with reference to Fig. 3 and Fig. 4 are described.

[0058] Fig. 3 is a conceptual cross-sectional diagram illustrating the flow of the working fluid during the rebound stroke of the electronically controlled internal damper in accordance with the embodiment of the present invention, and Fig. 4 is a conceptual cross-sectional diagram illustrating the flow of the working fluid during the compression stroke of the electronically controlled internal damper in accordance with the embodiment of the present invention.

[0059] Reference symbols used in Fig. 3 and Fig. 4 are not shown, are referred to those of Fig. 1 and Fig. 2 related.

[0060] Arrows that are represented by thick continuous lines in Fig. 3 and Fig. 4 represent the main channel formed by the working fluid corresponding to the rebound stroke and the compression stroke.

[0061] Arrows that are separated by thin continuous lines in Fig. 3 and Fig. 4 represent directions in which the compression-side channel is formed in the soft mode.

[0062] Arrows separated by dotted lines in Fig. 3 and Fig. 4 represent directions in which the rebound side channel is formed in the soft mode.

[0063] Arrows indicated by dashed lines in Fig. 3 and Fig. 4 represent directions in which the channel is formed in the hard mode.

[0064] The flow rate bypassed in the soft mode or the hard mode is divided into two locations, and the flow force of the driven spool 600 can be reduced by the divided bypass channels.

[0065] In other words, since the flow force of the driven spool 600 is proportional to the square of the flow rate of the working fluid flowing in the rebound stroke or the compression stroke, and the total bypassed flow rate is equal, the working fluid, which is 1 / 2 of the total flow rate, migrates through the divided bypass passages as described above, so the flow force of the driven spool 600 is reduced by 1 / 2.

[0066] A basic technical idea of ​​the present invention is to provide the electronically controlled internal damper capable of improving ride comfort by reducing the low-speed damping force of the soft mode in the driven spool and the spool rod without increasing their sizes.

[0067] The above-described configurations in accordance with the present invention can achieve the following effects.

[0068] Due to the structure including the damping unit forming the bypass passage in the upper portion thereof during the compression stroke in the hard mode or the soft mode and forming the bypass passage in the lower portion thereof during the rebound stroke in the hard mode or the soft mode, it is possible to improve ride comfort by reducing the low-speed damping force of the soft mode in the driven spool and the spool rod without increasing their sizes.

[0069] Therefore, compared to the conventional electronically controlled internal damper, the bypass flow rate is increased and the degree of freedom for reducing the low-speed damping force in the soft mode is increased. Therefore, it is possible to provide a product with high reliability.

[0070] Although the embodiments of the present invention have been described with reference to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention as defined in the following claims.

Claims

[1] Electronically controlled internal damper with: a control piston rod (500) formed to have a stepped shape in a lower end portion of a piston rod (700) that reciprocates in a cylinder; a valve unit comprising: a main piston (100) having a central portion through which the control piston rod (500) extends, and which divides the cylinder into an upper cylinder chamber (U) and a lower cylinder chamber (D) and in which a compression passage (102) and a rebound passage (101) are arranged alternately; a compression holder (200) arranged above the main piston (100); a rebound holder (400) arranged below the main piston (100); a first housing (310) arranged above the compression holder (200) to form a first pilot chamber (311) therein and having an open bottom; and a second housing (320) arranged below the rebound holder (400) to form a second pilot chamber (322) therein and having an open top; a driven control piston (600) which moves back and forth along a guide channel (510) which penetrates a central portion of the control piston rod (500); and a damping unit (900) provided on an outer peripheral surface of the driven spool (600) and the spool rod (500) for allowing a working fluid to flow to the inside and outside of the spool rod (500) through the guide channel (510) during a compression stroke or a rebound stroke, forming a first bypass channel (911) in an upper portion of the spool rod (500) during the compression stroke in a hard mode, forming a second bypass channel (916) in a lower portion of the spool rod (500) during the rebound stroke in the hard mode, forming a third bypass channel (913) during the compression stroke in a soft mode, and forming a fourth bypass channel (914) during the rebound stroke in the soft mode. [2] An electronically controlled internal damper according to claim 1, wherein the third and fourth bypass passages (913, 914) formed between the control piston rod (500) and the driven control piston (600) during the compression stroke or the rebound stroke in the soft mode are provided between the first and second bypass passages (911, 916) formed between the control piston rod (500) and the driven control piston (600) during the compression stroke or the rebound stroke in the hard mode. [3] An electronically controlled internal damper according to claim 1, wherein the first bypass passage (911) formed between the control piston rod (500) and the driven control piston (600) during the compression stroke in the hard mode is provided above the third bypass passage (913) formed between the control piston rod (500) and the driven control piston (600) during the compression stroke in the soft mode. [4] The electronically controlled internal damper according to claim 1, wherein the fourth bypass passage (914) formed between the control piston rod (500) and the driven control piston (600) during the rebound stroke in the soft mode is provided above the second bypass passage (916) formed between the control piston rod (500) and the driven control piston (600) during the rebound stroke in the hard mode. [5] Electronically controlled internal damper according to claim 1, wherein the damping unit (900) comprises: a communication arrangement (910) provided in the control piston rod (500) such that the first pilot chamber (311) of the first housing (310), the compression stage holder (200), the main piston (100), the rebound stage holder (400), and the second pilot chamber (322) of the second housing (320) communicate with the guide channel (510) from the upper side; and a guide assembly (920) provided along an outer peripheral surface of the driven control piston (600) and allowing flow of the working fluid from the upper and lower sides of the driven control piston (600) through the communication assembly (910) according to the compression stroke or the rebound stroke in the hard mode or the soft mode.

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