KR20090003019A - Damping force variable shock absorber - Google Patents

Abstract

A damping force variable shock absorber is provided to improve the ride comfort by reducing the frictional force with the rebound piston and compression piston and cylinder. A damping force variable shock absorber comprises a solenoid driving part(10) installed at the tip-end part of the piston rod moving up and down in the cylinder in which the working fluid is sealed; a spool guide installed at the tip-end part of the solenoid driving part and spool(30); a rebound piston(40) which is comprised in order to vary the damping force; and a compression piston(50) which is comprised in order to vary the damping force.

Description

Damping force variable shock absorber {DAMPING FORCE VARIABLE SHOCK ABSORBER}

1 is a longitudinal cross-sectional view of a damping force variable shock absorber according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A of FIG. 1. FIG.

3 is an enlarged view of a portion B of FIG. 1.

<Description of Signs of Major Parts of Drawings>

1: cylinder 2: piston rod

10: solenoid drive unit 20: spool guide

30: Spool 40: Rebound Piston

50: compression piston

The present invention relates to a damping force variable shock absorber, and more particularly, to a damping force variable shock absorber configured to allow the piston to continuously vary the damping force.

In general, the shock absorber of the vehicle is installed in a moving means such as a vehicle to absorb and mitigate the vibration or shock transmitted from the wheel in contact with the road surface during the driving.

The shock absorber is preferably appropriately adjusted damping force characteristics in order to improve the ride comfort and steering stability of the vehicle according to the road surface, driving conditions and the like. For example, during normal driving, the damping force of the shock absorber is preferably lowered to sufficiently absorb the vibrations caused by the unevenness of the road surface and improve the riding comfort, and to suppress the change in attitude of the vehicle body during turning, acceleration, braking, and high speed driving. It is desirable to increase the damping force in order to improve steering stability.

To this end, recently, a damping force variable shock absorber configured to properly adjust the damping force characteristics by varying the damping force using a pilot control damping force variable valve has been developed.

In the damping force variable shock absorber, the oil in the piston loss passes through the damping force variable valve during the tension stroke and flows into the reservoir chamber while forming the damping force by the resistance, and during the compression stroke, the oil in the piston compartment flows into the reservoir check valve. After passing through, it passes through the damping force variable valve and flows into the reservoir chamber by forming the damping force by the resistance.

In general, the damping force variable valve of the damping force variable shock absorber is a pilot control method that controls the pressure-flow characteristic by solenoid driving, and continuously controls the damping force variable. The damping force at the tension stroke and the compression stroke at the solenoid current is controlled. Configured to increase or decrease the damping force. For example, the damping force variable valve of the pilot control method by the solenoid drive controls the damping force at the tension stroke and the damping force at the compression stroke in soft mode or hard mode by solenoid current control. This damping force control is achieved by controlling the back pressure formation and regulation of the back pressure chamber in which the spool moving in accordance with the solenoid drive is formed behind the disk valve.

However, in the conventional damping force variable shock absorber, as described above, since the damping force variable valve configured so that damping force control is performed by adjusting the back pressure to the disk valve as the spool moving in accordance with the solenoid drive is provided on the outside of the shock absorber, There is a problem that the volume of shock absorber becomes large.

On the other hand, a damping force variable shock absorber has been developed that adds a variable damping force to the piston, but the cylinder is divided into a compression chamber and a rebound chamber to move up and down inside the cylinder, and the compression chamber and the rebound stroke according to the compression stroke and the rebound stroke. Due to the nature of the piston allowing selective fluid flow between the seals, there is a limit to the addition of variable damping force to the piston.

In particular, the technique of varying the damping force by the spool moving in accordance with the solenoid drive by adjusting the back pressure to the disk valve is due to the characteristics of the piston that allows selective fluid flow between the compression chamber and the rebound chamber while moving up and down inside the cylinder. However, there is a problem that is quite difficult to apply to the piston.

In order to solve this problem, the present inventors have developed a damping force continuous variable shock absorber configured to have a piston function as a damping force continuous variable valve in which the spool moving in accordance with the solenoid drive adjusts the back pressure to the disc valve. There is a bar.

The damping force variable shock absorber is provided with a solenoid drive unit provided at the distal end of a piston rod moving up and down in a cylinder filled with hydraulic oil, a spool guide and a spool provided at the distal end of the solenoid drive unit, and an upper portion of the outer circumferential surface of the spool guide. A rebound piston configured to vary the damping force while allowing fluid flow from the rebound chamber to the compression chamber during the rebound stroke, and to be spaced apart from the rebound piston at the lower circumference of the spool guide to the rebound chamber during the compression stroke. And a compression piston configured to vary the damping force while allowing fluid flow.

Conventionally, the outer circumferential surface of the rebound retainer of the rebound piston is used to seal the rebound piston and the compression piston between the rebound chamber and the compression chamber while allowing each of the rebound piston and the compression piston to sealably move relative to the cylinder. A band-shaped seal ring made of Teflon or the like was provided on each of the outer peripheral surfaces of the compression retainer of the compression piston and the compression piston.

However, when the seal rings are respectively provided on the rebound piston and the compression piston, the two seal rings contact and slide with respect to the cylinder, i.e., the piston and the cylinder contact at two places, so that the friction force increases (especially at low speed). There is a problem that adversely affects the ride comfort.

Accordingly, the present invention is to solve the problems of the prior art, and between the rebound piston and the compression piston between the rebound piston and the compression piston while providing one seal ring between the rebound piston and the compression piston and the cylinder. It is therefore an object of the present invention to provide a damping force continuously variable shock absorber which is configured such that each rebound piston and the compression piston are sealably movable relative to the cylinder while sealing.

In order to achieve the above object, the present invention, the solenoid drive unit is provided in the front end of the piston rod which moves up and down in the cylinder filled with the hydraulic oil, the spool guide and spool is provided at the end of the solenoid drive unit, and the spool guide A rebound piston installed above the outer circumferential surface of the pump and configured to vary the damping force while allowing fluid flow from the rebound chamber to the compression chamber during the rebound stroke and spaced apart from the rebound piston below the outer circumferential surface of the spool guide. A damping force variable shock absorber comprising a compression piston configured to vary the damping force while allowing fluid flow from the sea compression chamber to the rebound chamber, the rebound retainer of the rebound piston and the compression retainer of the compression piston. One end portion of the outer portion of one of the retainers is characterized in that it is formed to seal the outer portion of the other retainer.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a longitudinal cross-sectional view of a damping force variable shock absorber according to an embodiment of the present invention, Figures 2 and 3 is an enlarged view of the portion A and B of Figure 1, respectively. As shown, the damping force variable shock absorber according to the present embodiment, the function of the damping force continuous variable valve is included in the piston. That is, in the damping force variable shock absorber according to the present embodiment, the piston is the solenoid drive unit 10, the spool guide 20, the spool 30, the rebound piston 40, the compression piston 50 It is composed.

The solenoid drive part 10 is fixedly installed in the front-end | tip part of the piston rod 2, and consists of the solenoid 11 and the pressure rod 13 which moves up and down according to the electric current change of this solenoid 11. The piston rod 2 is comprised so that it may move up and down in the cylinder 1 in which hydraulic fluid was sealed according to the vibration of a vehicle body.

The spool guide 20 is a hollow rod and is provided at the tip of the solenoid drive unit 10. A plug 21 is installed at the lower end of the spool guide 20, and a coil spring 23 is embedded on the plug 21. The rebound piston side spool guide 20 is provided with a rebound first connection port 25a, a rebound second connection port 25b, and a rebound third connection port 25c in order from top to bottom. In the guide 20, the compression first connection port 26a, the compression second connection port 26b, and the compression third connection port 26c are formed in order from the bottom to the top.

The spool 30 is inserted into the spool guide 20 in a sealable up and down manner. The upper end of the spool 30 abuts the pressure rod 13 of the solenoid drive unit 10, and the lower end of the spool 30 has a coil spring 23 interposed on a plug 21 installed at the lower end of the spool guide 20. ). The rebound piston side spool 30 is provided with a rebound first small diameter portion 31, a rebound large diameter portion 32, and a rebound second small diameter portion 33 in order from the top to the bottom, and in the middle of the spool 30, The large diameter part 34 is formed, and the compression piston side spool 30 has the compression first small diameter part 35, the compression large diameter part 36, and the compression second small diameter part 37 in order from bottom to top. ) Is formed. Rebound first guide grooves 32a and rebound second guide grooves 32b are respectively formed at the upper and lower ends of the rebound large diameter portion 32, and the compression first guide grooves are disposed at the upper and lower ends of the compression large diameter portion 36, respectively. 36a and the compression second guide groove 36b are formed, respectively.

As the spool 30, whose upper end is elastically abutted, moves up and down to the lower end of the pressure rod 13 which moves up and down according to the current change of the solenoid 11, the rebound second connection port 25b is the rebound first guide groove. Or selectively communicate with the rebound second induction groove 32b, and the compression second connection port 26b is selectively with the compression first induction groove 36a or the compression second induction groove 36b. Communicate. Here, opening and closing of the flow path where the rebound second connection port 25b and the rebound second guide groove 32b communicate with each other, and the flow path where the compression second connection port 26b and the compression second guide groove 36b communicate with each other. Or it can be seen that the opening and closing degree is controlled according to the fine vertical movement of the spool 30.

The rebound second connection port 25b and the rebound second induction groove 32b form a variable orifice for rebound back pressure adjustment, and the compression second connection port 26b and the compression second induction groove 36b are compressed back pressure. To form an adjustable variable orifice. In addition, the rebound second connection port 25b and the rebound first guide groove 32a form a variable orifice for rebound bypass, and the compression second connection port 26b and the compression first guide groove 36a are compressed. A variable orifice for the bypass bypass is formed.

The rebound piston 40 is installed on the outer circumferential surface of the spool guide 20 and includes a rebound retainer 41 and a rebound back pressure forming retainer 43.

The rebound retainer 41 is formed through the first, second and third rebound orifices 41a, 41b, 41c therein. These first, second and third rebound orifices 41a, 41b, 41c form a rebound flow path. The rebound retainer 41 has an inverted U-shaped cross section in which a space is formed inside the lower portion.

In the rebound back pressure forming retainer 43, a back pressure forming orifice 43a is vertically penetrated therein. The rebound back pressure forming retainer 43 is sealingly fitted in the lower inner space of the rebound retainer 41, but is fitted between the rebound retainer 41 via the rebound disk valve 45.

The rebound disk valve 45 includes a rebound main disk 45a and a rebound back pressure forming disk 45b.

The rebound main disk 45a is arranged to cover the first rebound orifice 41a at the rear of the rebound retainer 41 to directly strike the hydraulic oil passing through the first rebound orifice 41a to generate a damping force. That is, the rebound main disk 45a opposes the hydraulic fluid flowing through the first rebound orifice 41a, and the hydraulic fluid flows toward the second and third rebound orifices 41b and 41c while being turned back in the process of opposing.

Also, inside the rebound main disk 45a, a slit S45a for flowing a part of the hydraulic oil passing through the first rebound orifice 41a in a direction other than the second and third rebound orifices 41b and 41c is provided. Is formed. The slit S45a is in constant communication with the rebound second connection port 25b of the spool guide 20. The slit S45a and the rebound second connection port 25b form a rebound fixed orifice.

The rebound back pressure forming disk 45b is provided behind the rebound main disk 45a and forms the rebound back pressure chamber 47 between the rebound back pressure forming retainer 43.

The rebound back pressure adjusting flow path forming disk 44 is formed behind the rebound back pressure forming retainer 43 so as to cover the rebound back pressure forming orifice 43a. A slit S44a is formed inside the rebound back pressure adjusting flow path forming disk 44, and a slit S44b is formed outside the rebound back pressure adjusting flow path forming disk 44. The slit S44a is in constant communication with the rebound third connecting port 25c and the rebound second small diameter portion 33 of the spool 30, and the slit S44b is the rebound piston 40 and the compression piston ( It is always in communication with the space between 50).

The slit S45a of the rebound main disk 45a, the rebound second connection port 25b of the spool guide 20, the rebound second guide groove 32b of the spool 30, and the rebound of the spool 30. The second small diameter portion 33, the rebound third connection port 25c of the spool guide 20, the slit S44a of the rebound back pressure adjusting flow path forming disk 44, and the rebound back pressure forming retainer 43. The rebound back pressure forming orifice 43a and the slit S44b of the rebound back pressure adjusting flow path forming disk 44 selectively introduce a part of the hydraulic oil flowing into the rebound flow path into the rebound back pressure chamber 47. A rebound back pressure adjusting flow path that leads to the compression chamber 1b is formed.

The slit S44b of the rebound back pressure adjusting flow path forming disk 44 has a space between the rebound piston 40 and the compression piston 50 in the rebound back pressure adjusting flow path immediately upstream of the rebound back pressure chamber 47. In other words, it flows toward the compression chamber 1b.

In addition, the rebound retainer 41 is provided with a rebound bypass orifice 41d which directly communicates the rebound first connection port 25a of the spool guide 20 and the second rebound orifice 41b. Slit S45a of rebound main disk 45a, rebound second connection port 25b of spool guide 20, rebound first guide groove 32a of spool 30, and rebound of spool 30. The first small diameter portion 31, the rebound first connection port 25a of the spool guide 20, and the rebound bypass orifice 41d are configured to pass a part of the hydraulic oil upstream of the rebound disk valve 45 to the rebound disk valve ( A rebound bypass flow path is formed to selectively bypass downstream of the rebound disc valve 45 without undergoing the damping action by 45).

Moreover, the rebound retainer 41 is provided with the rebound compression orifice 41e which is a rebound piston side compression flow path which makes hydraulic oil which flows from the compression piston 50 flow to the rebound chamber 1a at the time of a compression stroke.

In the upper part of the rebound retainer 41, the hydraulic oil of the rebound chamber 1a flows to the rebound flow path during the rebound stroke, and the hydraulic oil from the compression piston 50 is passed to the rebound chamber 1a during the compression stroke. The rebound inking disc 49 which flows is provided.

The compression piston 50 is installed below the outer circumferential surface of the spool guide 20 so as to be spaced apart from the rebound piston 40. The compression piston 50 includes a compression retainer 51 and a compression back pressure forming retainer 53.

The compression retainer 51 has first, second, and third compression orifices 51a, 51b, and 51c formed therethrough. These first, second and third compression orifices 51a, 51b, 51c form a compression flow path. The compression retainer 51 has a U-shaped cross section in which a space is formed inside the upper portion.

In the compression back pressure forming retainer 53, a back pressure forming orifice 53a penetrates and is formed vertically therein. The compression back pressure-forming retainer 53 is sealed in the upper inner space of the compression retainer 51, but is fitted between the compression retainer 51 via the compression disk valve 55.

The compression disk valve 55 includes a compression main disk 55a and a compression back pressure forming disk 55b.

The compression main disk 55a is arranged to cover the first compression orifice 51a at the rear of the compression retainer 51 to directly strike the hydraulic oil passing through the first compression orifice 51a to generate a damping force. . In other words, the compression main disk 55a opposes the hydraulic fluid flowing through the first rebound orifice 51a, and causes the hydraulic fluid to flow to the second and third compression orifices 51b and 51c while being flipped back in the process of opposing. .

In addition, a slit for allowing a portion of the hydraulic oil passing through the first compression orifice 51a to flow in a direction other than the second and third compression orifices 51b and 51c inside the compression main disk 55a ( S55a) is formed. The slit S55a is in constant communication with the compression second connection port 26b of the spool guide 20. The slit S55a and the compression second connection port 26b form a compression fixing orifice.

The compression back pressure forming disk 55b is provided behind the compression main disk 55a and forms the compression back pressure chamber 57 between the compression back pressure forming retainer 53.

The compression back pressure adjustment flow path forming disk 54 is formed behind the compression back pressure forming retainer 53 so as to cover the compression back pressure forming orifice 53a. A slit S54a is formed inside the compression back pressure adjusting flow path forming disk 54, and a slit S54b is formed outside the compression back pressure adjusting flow path forming disk 54. The slit S54a is in constant communication with the compression third connecting port 26c and the compression second small diameter portion 37 of the spool 30, and the slit S54b is compressed with the rebound piston 40. It is in constant communication with the space between the pistons 50.

The slit S55a of the compression main disk 55a, the compression second connection port 26b of the spool guide 20, the compression second guide groove 36b of the spool 30, and the spool 30 Compression second small diameter portion 37, the compression third connection port 26c of the spool guide 20, the slit (S54a) of the compression back pressure adjustment flow path forming disk 54, and the compression The compression back pressure forming orifice 53a of the back pressure forming retainer 53 and the slit S54b of the compression back pressure adjusting flow path forming disk 54 selectively compress a part of the hydraulic oil flowing into the compression flow path. A compression back pressure control flow path is formed to flow into the back pressure chamber 57 and to pass through the rebound chamber 1a.

The slit (S54b) of the compression back pressure adjusting flow path forming disk 54 passes a portion of the hydraulic oil in the compression back pressure adjusting flow path immediately upstream of the compression back pressure chamber 57 to the rebound piston 40 and the compression piston 50. It flows into the space between, ie, to the rebound chamber 1b.

Moreover, the compression retainer 51 is provided with the compression bypass orifice 51d which directly connects the compression first connection port 26a of the spool guide 20 and the second compression orifice 51b. The slit S55a of the compression main disk 55a, the compression second connection port 26b of the spool guide 20, the compression first guide groove 36a of the spool 30, and the spool 30 Of the compression first small diameter portion 35, the compression first connection port 26a of the spool guide 20, and the compression bypass orifice 51d are provided from the upstream of the compression disk valve 55. A compression bypass flow path is formed so as to selectively bypass a part of the downstream portion of the compression disk valve 55 without undergoing a damping action by the compression disk valve 55.

Moreover, the compression retainer 51 is provided with the compression rebound orifice 51e which is the compression piston side rebound flow path which flows the hydraulic oil which flows out from the rebound piston 40 toward the compression chamber 1b at the time of a rebound stroke.

In the lower portion of the compression retainer 51, the hydraulic oil of the compression chamber 1b flows into the compression flow path during the compression stroke, and the hydraulic oil from the rebound piston 40 is passed through the compression chamber during the rebound stroke. A compression intake disk 59 for flowing to 1b) is provided.

In the present invention, one end portion of the outer portion of the rebound retainer 41 of the rebound piston 40 is extended to seal the outer portion of the compression retainer 51 of the compression piston 50.

In addition, the inner diameter of the extended one end portion of the outer portion of the rebound retainer 41 of the rebound piston 40 is larger than the outer diameter of the outer portion of the compression retainer 51 of the compression piston 50, and the rebound piston 40 The seal ring 52 is provided between the extended end of the outer part of the rebound retainer 41 and the outer part of the compression retainer 51 of the compression piston 50. More specifically, the seal ring 52 is installed on the inner circumferential surface of the extended one end of the outer portion of the rebound retainer 41 of the rebound piston 40, and is an O-ring having a sealing function, whereby the rebound piston 40 And the compression piston 50 are sealed with respect to the rebound chamber 1a and the compression chamber 1b.

Here, a seal ring 42 is provided between the extended end of the outer portion of the rebound retainer 41 of the rebound piston 40 and the outer portion of the compression retainer 51 of the compression piston 50. More specifically, the seal ring 42 is installed on the outer circumferential surface of the rebound retainer 41 and is a Teflon band having a sealing function and a guiding function, whereby the rebound piston 40 is sealed to the cylinder 1. Shanghai-dong becomes possible.

Therefore, in the present invention, only one seal ring 42 provided in the rebound piston 40 comes into contact with the cylinder 1. That is, in the present invention, the rebound piston 40 and the compression piston 50 come into contact with the cylinder 1 at one place. When the rebound piston 40 and the compression piston 50 come into contact with the cylinder 1 at one place, the rebound piston 40 and the compression piston 50 come into contact with the cylinder 1 at two places. It can be seen that the friction is significantly reduced.

In the above, one end portion of the outer portion of the rebound retainer 41 of the rebound piston 40 is extended, and the inner diameter thereof is larger than the outer diameter of the outer portion of the compression retainer 51 of the compression piston 50, so that the compression piston 50 Although it is illustrated that the seal ring 42 is formed on the outer circumferential surface of the rebound retainer 41 and is formed to seal the outer portion of the compression retainer 51 of the compression retainer 51, the compression retainer 51 of the compression piston 50 is One end portion of the outer portion of the retracted piston 40 is formed so that the inner diameter is larger than the outer diameter of the outer portion of the rebound retainer 41 of the rebound piston 40 is formed to seal the outer portion of the rebound retainer 41 of the rebound piston 40 It will be appreciated that the seal ring 42 is provided on the outer circumferential surface of the compression retainer 51 within the scope of the present invention.

While the invention has been described above with reference to specific embodiments, various modifications, changes or modifications may be made in the art within the spirit and scope of the appended claims, and thus, the foregoing description and drawings It should be construed as illustrating the present invention rather than limiting the technical spirit of the present invention.

As described above, according to the damping force variable shock absorber of the present invention, the rebound piston and the compression piston are provided between the rebound piston and the compression piston while providing one seal ring between the rebound piston and the compression piston and the cylinder. Since each of the rebound piston and the compression piston is sealably movable relative to the cylinder while sealing, the frictional force between the rebound piston and the compression piston and the cylinder is reduced, thereby improving the riding comfort.

Claims (7)

The solenoid drive unit is installed at the distal end of the piston rod moving up and down in the cylinder filled with hydraulic fluid, the spool guide and the spool installed at the distal end of the solenoid drive unit, and the upper portion of the outer circumferential surface of the spool guide. A rebound piston configured to vary the damping force while allowing fluid flow from the compression chamber to the compression chamber and spaced apart from the rebound piston below the outer circumferential surface of the spool guide to allow fluid flow from the compression chamber to the rebound chamber during the compression stroke. A damping force variable shock absorber comprising a compression piston configured to vary a damping force, A damping force variable shock absorber, characterized in that the one end portion of the outer portion of the retainer of the rebound retainer of the rebound piston and the compression retainer of the compression piston is extended to seal the outer portion of the other retainer. The method according to claim 1, The inner diameter of the extended one end of the outer portion of the one retainer is larger than the outer diameter of the outer portion of the other retainer, A damping force variable shock absorber, characterized in that a seal ring is provided between the extended end of the outer portion of the one retainer and the outer portion of the other retainer. The method according to claim 2, And the seal ring provided between the extended one end of the outer portion of the one retainer and the outer portion of the other retainer is an O-ring having a sealing function. The method according to claim 1, A damping force variable shock absorber, characterized in that the seal ring is installed on the outer peripheral surface of the one retainer surrounding a portion of the outer peripheral surface of the other retainer. The method according to claim 4, And a seal ring provided on an outer circumferential surface of the one retainer which surrounds a portion of the outer circumferential surface of the other retainer is a Teflon band having a sealing function and a guiding function. The method according to claim 2, One end of an outer portion of the rebound retainer of the rebound piston is extended, A damping force variable shock absorber, characterized in that the inner diameter of one end of the extended portion of the rebound retainer of the rebound piston is larger than the outer diameter of the outer portion of the compression retainer of the compression piston. The method according to claim 2, One end of an outer portion of the compression retainer of the compression piston is extended, And an inner diameter of an extended end of the outer portion of the compression retainer of the compression piston is larger than an outer diameter of the outer portion of the rebound retainer of the rebound piston.

Images