JP2010053923A - Viscous coupling and suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a viscous coupling enabling more accurate management of a plate gap, and a suspension device mounted with the viscous coupling. <P>SOLUTION: The viscous coupling 10 includes a shaft 20, a case body 12 forming a working chamber 16 storing a viscous fluid, a plurality of inner plates 30 connected so that movement with respect to the shaft 20 around an axis of the shaft 20 is regulated and movement to the axial direction is not regulated, a plurality of outer plates 40 fixed to the case body 12 and arranged alternately with the inner plate 30 in the working chamber 16, a plurality of spacers 50 arranged alternately with the inner plate 30 and connected in such a manner of not regulating the movement to the axial direction with respect to the shaft 20 and defining the gap between the inner plate 30 and the outer plate 40, and a spring 60 for energizing the inner plate 30 and the spacer 50 to the axial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a viscous coupling and a suspension device equipped with the viscous coupling.

Conventionally, the structure which provided the viscous coupling in the vehicle is proposed (for example, refer patent document 1). In Patent Document 1, in a working chamber space constituted by a case, a disk (outer plate) fixed to the inner peripheral surface of the case and a rotor (inner plate) fixed to the outer peripheral surface of the shaft inserted into the case. Are alternately stacked, and the electrorheological fluid is enclosed. The shaft is connected to the first electrode, the case is connected to the second electrode, and a collar and a spacer are arranged between the rotor and the disk so that the rotor and the disk do not contact each other. In this viscous coupling, a voltage is applied to the electrorheological fluid to adjust the viscosity of the electrorheological fluid, and a torque (damping force) is obtained by rotating the case and the shaft relative to each other so that the rotor shears the electrorheological fluid. Is generated.
Japanese Patent Laid-Open No. 10-159885 JP 2007-64329 A

  A viscous coupling provides a stable damping force when the distance between the outer plate and the inner plate (hereinafter sometimes collectively referred to as a plate) is not constant, or when there is play in the plate fixing part of the case or shaft. It may not be possible. Therefore, in the viscous coupling, it is preferable that the gap between the plates is kept at a predetermined interval, and the plates are assembled to the case and the shaft without any play.

  By the way, when the viscous coupling is used as a suspension device for a vehicle, it is required to reduce the plate interval so that a damping force necessary for the suspension device can be obtained. In general, there is a demand for downsizing of all parts, and naturally downsizing of in-vehicle parts is also required. By realizing the miniaturization of the parts, it is possible to effectively use the space for mounting the parts and to mount the parts in a narrow space. In the viscous coupling, the size can be reduced by narrowing the plate interval.

  As described above, when the plate interval of the viscous coupling is narrowed for the purpose of increasing the damping force or reducing the size of the apparatus, the change in the plate interval greatly affects the magnitude of the damping force. Therefore, in order to obtain a stable damping force, it is necessary to manage the plate interval with high accuracy. Patent Document 1 discloses a technique in which a collar and a spacer are arranged between plates to keep the plate interval constant. According to this method, the plate interval can be managed by adjusting the thickness of the collar and the spacer. However, in such a configuration, since the inner plate and the outer plate are always in contact with the collar or the spacer, there is a problem that the frictional resistance is large and a desired damping force cannot be obtained. Further, when the flatness of the plate and the spacer is low, there is a problem that the plate interval cannot be managed with high accuracy only by adjusting the thickness of the collar and the spacer.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a viscous coupling capable of managing the plate interval with higher accuracy, and a suspension device equipped with the viscous coupling. There is.

  In order to solve the above-mentioned problems, a viscous coupling according to an aspect of the present invention includes a shaft, a case body that forms a working chamber that accommodates a viscous fluid, and a movement of the shaft in the direction around the shaft with respect to the shaft A plurality of first plates coupled so that movement of the shaft in the axial direction is not restricted, a plurality of second plates fixed to the case body and arranged alternately with the first plates in the working chamber, A plurality of spacers arranged alternately with one plate, connected so as not to restrict axial movement with respect to the shaft, and forming a space between the first plate and the second plate, and the first plate and the spacer as the shaft And an urging member for urging in the direction.

  According to this aspect, the plate interval can be managed with higher accuracy.

  In the above aspect, the spacer has an axial length longer than an axial length of the second plate, and the first plate and the second plate are different depending on a difference between the axial length of the spacer and the axial length of the second plate. A distance from the plate may be formed. According to this, the plate interval can be managed more easily and with high accuracy.

  In the above aspect, the spacer is made of a member having a smaller coefficient of thermal expansion than that of the second plate, the distance between the first plate and the second plate is narrowed by the thermal expansion of the spacer and the second plate, and the spacer and the second plate are contracted. Thus, the distance between the first plate and the second plate may be increased. According to this, the damping force can be generated more stably.

  Another aspect of the present invention is a suspension device. The suspension device includes the viscous coupling according to any one of the above-described aspects, and the shock is buffered by a damping force generated in accordance with the relative rotation between the shaft and the case body. According to this suspension device, it is possible to stably generate the damping force by mounting the viscous coupling capable of managing the plate interval with higher accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, the suspension coupling which mounts the viscous coupling which can manage a plate space | interval with higher precision, and the viscous coupling can be provided.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  FIG. 1 shows a mounting structure of a suspension device according to an embodiment of the present invention. The suspension device 1 includes a carrier 3 that rotatably supports the wheel 2, and a lower arm 4 and an upper arm 5 that support the carrier 3 so as to be swingable up and down. The vehicle main body 6, the lower arm 4, the upper arm 5 and the carrier 3 constitute a link mechanism 7, and the lower arm 4 and the upper arm 5 are rotatably attached to the vehicle main body 6.

  In the present embodiment, the suspension device 1 is configured by including a viscous coupling 10 at a joint portion of the link mechanism 7. The link mechanism 7 in this embodiment constitutes a four-bar linkage mechanism, and the viscous coupling 10 includes a joint portion 8a between the vehicle body 6 and the lower arm 4, a joint portion 8b between the vehicle body 6 and the upper arm 5, and an upper arm. 5 and the joint portion 8 c between the carrier 3 and the joint portion 8 d between the lower arm 4 and the carrier 3. In the example shown in FIG. 1, the viscous coupling 10 constitutes a joint portion 8 a of the vehicle body 6 and the lower arm 4. Hereinafter, the joint portions 8a to 8d are collectively referred to as “joint portion 8”.

  The viscous coupling 10 includes a case body and a shaft protruding from the case body. The case body is attached to one link, and the shaft is attached to a link adjacent to the link, whereby the joint portion 8 that connects the two adjacent links so as to be relatively rotatable is configured. In the example shown in FIG. 1, the case body is fixed to the vehicle body 6, and the shaft is connected to the lower arm 4, so that the shaft and the case body rotate relative to each other according to the vertical movement of the lower arm 4, thereby reducing the damping force. appear.

  In the present embodiment, the structure of the link mechanism 7 is an example, and the suspension device 1 may have another link mechanism. Further, in the example shown in FIG. 1, the viscous coupling 10 constitutes the joint portion 8a, but other joint portions 8b, 8c and 8d may be constituted, and a plurality of viscous couplings 10 may constitute a plurality of joints. The unit 8 may be configured.

  FIG. 2 shows a configuration of the viscous coupling 10 according to the present embodiment. The viscous coupling 10 includes a shaft 20 that is connected to the lower arm 4 (see FIG. 1) and rotates according to the vertical movement of the lower arm 4, and a cylindrical case body 12 that is connected to the vehicle body 6 (see FIG. 1). Prepare. The shaft 20 may be connected to the vehicle body 6, the case body 12 may be connected to the lower arm 4, and the shaft 20 and the case body 12 may be connected to other adjacent links in the link mechanism 7.

  The case body 12 includes a housing portion 13 having an opening on one side and a lid portion 14 that closes the opening. The shaft 20 is supported so as to be rotatable relative to the case body 12 by a bearing 18 a provided in the housing part 13 and a bearing 18 b provided in the lid part 14. A working chamber 16 is formed between the outer peripheral surface of the shaft 20 and the inner peripheral surface of the case body 12 (the casing portion 13), and is filled with a viscous fluid such as silicone oil. The working chamber 16 includes an oil seal 22a, It is sealed by 22b. For example, the length of the case body 12 is about 40 to 50 mm in the axial direction of the shaft 20 and about 200 mm in the direction perpendicular to the axial direction of the shaft 20.

  A plurality of inner plates 30 as first plates are coupled to the outer peripheral surface of the shaft 20 so that the movement of the shaft 20 in the direction around the axis is restricted and the movement in the axial direction is not restricted. The inner plate 30 is connected to the shaft 20 by, for example, serration fitting. A plurality of outer plates 40 as second plates are fixed to the inner peripheral surface of the casing portion 13 of the case body 12. The outer plate 40 is fixed by, for example, serration fitting so that the movement of the shaft 20 in the axial direction and the axial direction is restricted with respect to the housing part 13. The plurality of inner plates 30 and the plurality of outer plates 40 are arranged at predetermined plate intervals Lc alternately in the working chamber 16. The method of engaging the inner plate 30 with the shaft 20 and the method of fixing the outer plate 40 to the housing part 13 can be changed as appropriate according to the magnitude of the damping force required for the viscous coupling 10.

  When the lower arm 4 moves up and down due to the behavior of the wheels 2, the shaft 20 rotates and the shaft 20 and the case body 12 rotate relative to each other. As a result, the plurality of inner plates 30 and the outer plate 40 connected to each other rotate in a differential manner, and a shearing force is generated in the viscous fluid in accordance with the rotation difference to generate torque. This generated torque becomes a damping force in the suspension device 1.

FIG. 3 shows the relationship between the differential rotation speed Δn due to the viscous coupling 10 and the torque T ₀ generated. When the viscous coupling 10 is incorporated in the suspension device 1 as shown in FIG. 1, the differential rotation speed Δn corresponds to the suspension stroke speed, and the torque T ₀ corresponds to the damping force. As shown in FIG. 3, the torque T ₀ and the differential rotation speed Δn have a proportional relationship.

Hereinafter, a calculation formula of the torque T ₀ generated in the viscous coupling 10 is shown.

Lc: Plate spacing N: Fluid viscosity e: Density ra: Large diameter of the plate overlap region ri: Small diameter of the plate overlap region Δn: Differential rotation (relative rotation) number

As shown in Equation 1, in the viscous coupling 10, torque T ₀ is generated in a relationship inversely proportional to the plate interval Lc between the inner plate 30 and the outer plate 40. Therefore, in order to stably generate the torque T ₀ , it is necessary to manage the plate interval Lc with high accuracy. In particular, the smaller the plate interval Lc, the greater the amount of change in damping force corresponding to the change in the plate interval Lc. Therefore, it is required to manage the plate interval Lc with higher accuracy.

  Returning to FIG. 2, in the viscous coupling 10 of the present embodiment, the plurality of spacers 50 for forming the plate interval Lc are alternately arranged with the inner plate 30, and the movement of the shaft 20 in the axial direction is not restricted. Is engaged with the shaft 20. In the present embodiment, the axial length of the spacer 50, that is, the thickness is set to be larger than the thickness of the outer plate 40, thereby forming the plate interval Lc. The thicknesses of the inner plate 30 and the outer plate 40 are the thicknesses required to obtain the strength required for obtaining the damping force required for the viscous coupling 10, and are each about 0.3 mm, for example. The thickness of the spacer 50 is determined according to the required damping force and the thicknesses of the inner plate 30 and the outer plate 40, and is about 0.35 mm, for example. The spacer 50 may not be provided over the entire circumference of the shaft 20 and may be cut out at a predetermined interval, for example. According to this, the weight of the viscous coupling 10 can be reduced.

  Further, the distance plate 62 and the press receiving portion 64 are attached to the shaft 20 so as to sandwich the alternately arranged inner plates 30 and spacers 50. Further, a spring locking portion 66 is attached to the end portion of the shaft 20 opposite to the press receiving portion 64. A spring 60 is attached to the shaft 20 as a biasing member that biases the inner plate 30 and the spacer 50 in the axial direction of the shaft 20.

  Specifically, the press receiving portion 64 is attached to one end side of the shaft 20 so as to contact the bearing 18a. The inner plate 30 or the spacer 50 (inner plate 30 in FIG. 2) located on the outermost side on the end side is in contact with the pressure receiving portion 64. A distance plate 62 is attached to the shaft 20 on the opposite side of the pressure receiving portion 64 with the inner plates 30 and the spacers 50 arranged alternately. Then, the inner plate 30 or the spacer 50 (the spacer 50 in FIG. 2) located on the outermost side on the opposite side is in contact with the distance plate 62.

  Further, the spring locking portion 66 is attached to the other end portion side of the shaft 20 so as to contact the bearing 18b. A spring 60 as a biasing member that biases the inner plate 30 and the spacer 50 in the axial direction of the shaft 20 is attached to the shaft 20 so as to be sandwiched between the distance plate 62 and the spring locking portion 66. .

  The inner plate 30, the spacer 50, and the distance plate 62 are attached to the shaft 20 so as to be movable in the axial direction of the shaft 20. The spring 60 is provided in a compressed state between the distance plate 62 and the spring locking portion 66. Therefore, the force that presses the distance plate 62 and the spring locking portion 66 of the spring 60 acts as a biasing force that biases the inner plate 30, the spacer 50, and the distance plate 62 toward the pressing receiving portion 64. Thereby, the inner plate 30, the spacer 50, and the distance plate 62 are urged | biased by the press receiving part 64 side. The spacer 50 and the distance plate 62 may or may not be restricted from movement in the direction around the shaft 20.

  Thus, the inner plate 30 and the spacer 50 are urged in the axial direction of the shaft 20 by the spring 60, so that the distance plate 62 and the inner plate 30 positioned on the outermost side on the side facing the distance plate 62 are used. The defined plate existence region width Ls is constant. According to this, even if the planarity of the inner plate 30 and the spacer 50 is low due to warpage or the like caused by press molding, the plate existing region width Ls can be kept constant.

Since the plate existence region width Ls is kept constant regardless of the degree of flatness caused by the warp of the inner plate 30 and the spacer 50, the total plate interval ΣLc can be defined by the following equation (2). .
ΣLc = Σt _IP + Σt _SP −Σt _OP (Equation 2)
t _IP : thickness of the inner plate 30 t _OP : thickness of the outer plate 40 t _SP : thickness of the spacer 50

As shown in Expression 2, the total plate interval ΣLc can be defined by the thicknesses of the inner plate 30, the outer plate 40, and the spacer 50. Therefore, the plate interval Lc can be managed with high accuracy by adjusting the thicknesses of the inner plate 30, the outer plate 40, and the spacer 50. Furthermore, in this embodiment, since the plate interval Lc is formed by making the thickness t _SP of the spacer 50 different from the thickness t _OP of the outer plate 40, the plate interval Lc is set to (t _SP −t _OP ). / 2 can be defined. Therefore, the plate interval Lc can be managed with high accuracy by adjusting the thickness t _SP of the spacer 50 and the thickness t _OP of the outer plate 40.

  In the viscous coupling 10 of the present embodiment, the spacer 50 is made of a member having a smaller coefficient of thermal expansion than the outer plate 40. For example, the inner plate 30 and the outer plate 40 are made of aluminum, and the spacer 50 is made of iron. Alternatively, the inner plate 30 and the outer plate 40 are made of iron, and the spacer 50 is made of ceramics.

  According to this, the following effects can be obtained. That is, for example, when the temperature of the environment in which the viscous coupling 10 is used changes, the viscosity of the viscous fluid changes, and thereby the damping force of the viscous coupling 10 changes. When the temperature rises, the viscosity of the viscous fluid decreases, and the decrease in viscosity acts in the direction of decreasing the damping force. On the other hand, the inner plate 30, the outer plate 40, and the spacer 50 are thermally expanded due to this temperature rise, and the thickness is increased. However, in this embodiment, the inner plate 30 and the spacer 50 are urged by the spring 60. When the inner plate 30 and the spacer 50 are thermally expanded to increase their thickness, the spring 60 contracts by the increased thickness. At this time, if the thermal expansion coefficients of the outer plate 40 and the spacer 50 are the same, the total plate interval ΣLc does not change. For this reason, the damping force decreases due to the temperature rise.

  On the other hand, by making the thermal expansion coefficient of the spacer 50 smaller than the thermal expansion coefficient of the outer plate 40, the plate interval Lc can be reduced by the thermal expansion of both. The decrease in the plate interval Lc acts in the direction of increasing the damping force. Therefore, when the temperature rises, the damping force is reduced due to the decrease in the viscosity of the viscous fluid, and the damping force is increased due to the decrease in the plate interval Lc corresponding to the thermal expansion of the outer plate 40 and the spacer 50. A change in damping force is suppressed. On the other hand, when the temperature of the environment in which the viscous coupling 10 is used decreases, the damping force increases due to the increase in the viscosity of the viscous fluid, and the damping due to the increase in the plate interval Lc corresponding to the contraction of the outer plate 40 and the spacer 50. A force reducing action occurs, and the change in the total damping force is suppressed. Therefore, according to the viscous coupling of this embodiment, it is possible to suppress a change in damping force due to a temperature change and keep the damping force constant.

  Then, an example of the assembly method of the viscous coupling 10 is demonstrated.

  First, the housing part 13 is arranged so that the opening is on the top with the lid part 14 removed. Then, the pressure receiving portion 64 is placed on the bearing 18a, and the shaft 20 is inserted so as to penetrate the pressure receiving portion 64 and the bearing 18a. Subsequently, the inner plate 30 is inserted into the shaft 20, and the lower surface of the inner plate 30 comes into contact with the press receiving portion 64. Next, the spacer 50 is inserted into the shaft 20, and the lower surface of the spacer 50 comes into contact with the upper surface of the inner plate 30 that has been previously inserted. Thereafter, the outer plate 40 is attached and fixed at a predetermined position of the housing portion 13.

  When this is repeated and all of the inner plate 30, the spacer 50, and the outer plate 40 are attached, the distance plate 62, the spring 60, and the spring locking portion 66 are inserted into the shaft 20 in this order. Subsequently, silicon oil as a viscous fluid is filled in the housing portion 13, and the lid portion 14 is attached to complete the viscous coupling 10. Note that the viscous coupling 10 may be formed by filling silicon oil from the oil hole after sealing the lid 14 and sealing the oil hole after filling.

  Summarizing the operational effects of the configuration described above, in the viscous coupling 10 according to the present embodiment, the inner plate 30 and the spacer 50 are connected to the shaft 20 so that the movement of the shaft 20 in the axial direction is not restricted. Is biased by the spring 60 in the axial direction of the shaft 20. Therefore, warpage of the inner plate 30 and the spacer 50 can be eliminated, and the total plate interval ΣLc can be defined by the thickness of the inner plate 30, the outer plate 40, and the spacer 50. Therefore, the plate interval Lc can be managed with high accuracy. Moreover, since the inner plate 30 and the spacer 50 are urged by the spring 60, rattling of the inner plate 30 and the spacer 50 is suppressed, and a stable damping force can be obtained.

  In addition, since the plate interval Lc is formed by making the thickness of the spacer 50 larger than the thickness of the outer plate 40, the plate interval Lc is defined as the difference between the thickness of the spacer 50 and the thickness of the outer plate 40. Can do. Therefore, the plate interval Lc can be managed more easily and with high accuracy.

  Further, when the spacer 50 is made of a member having a smaller coefficient of thermal expansion than the outer plate 40, the plate interval Lc changes due to a temperature change. According to this, it is possible to compensate for the change in the damping force accompanying the change in the viscosity of the viscous fluid according to the temperature change, and thereby it is possible to generate the damping force generated by the viscous coupling 10 more stably. .

  The present invention is not limited to the above-described embodiment, and an appropriate combination of the elements of the embodiment is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to the embodiments based on the knowledge of those skilled in the art, and the embodiments to which such modifications are added can be included in the scope of the present invention. . The configuration shown in each figure is for explaining an example, and any configuration that can achieve the same function can be changed as appropriate, and the same effect can be obtained.

It is a figure which shows the attachment structure of the suspension apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of a viscous coupling. It is a figure which shows the relationship between the differential rotation speed by viscous coupling, and the generated torque.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Suspension apparatus, 2 Wheel, 3 Carrier, 4 Lower arm, 5 Upper arm, 6 Vehicle main body, 7 Link mechanism, 8, 8a, 8b, 8c, 8d Joint part, 10 Viscous coupling, 12 Case body, 13 Housing part, 14 Lid, 16 Working chamber, 18a, 18b Bearing, 20 Shaft, 22a, 22b Oil seal, 30 Inner plate, 40 Outer plate, 50 Spacer, 60 Spring, 62 Distance plate, 64 Press receiving part, 66 Spring locking part , Lc plate interval, Ls plate existing area width.

Claims (4)

A shaft,
A case body forming a working chamber for containing the viscous fluid;
A plurality of first plates connected to the shaft so that the movement of the shaft in the axial direction is restricted and the movement of the shaft in the axial direction is not restricted;
A plurality of second plates fixed to the case body and arranged alternately with the first plates in the working chamber;
A plurality of spacers arranged alternately with the first plate, connected so as not to restrict movement in the axial direction with respect to the shaft, and forming a gap between the first plate and the second plate;
A viscous coupling comprising: a biasing member that biases the first plate and the spacer in the axial direction.   The spacer has a length in the axial direction that is longer than a length in the axial direction of the second plate, and the spacer has a length difference between the length in the axial direction of the spacer and the length in the axial direction of the second plate. The viscous coupling according to claim 1, wherein an interval between one plate and the second plate is formed. The spacer is made of a member having a smaller coefficient of thermal expansion than the second plate,
The space between the first plate and the second plate is narrowed by thermal expansion of the spacer and the second plate, and the space between the first plate and the second plate is widened by contraction of the spacer and the second plate. The viscous coupling according to claim 1 or 2, characterized in that   A suspension device comprising the viscous coupling according to any one of claims 1 to 3, wherein an impact is buffered by a damping force generated according to relative rotation between the shaft and the case body.

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