JP2009061825A - Suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension device with a simple structure, which makes compatible suppression of rolling and pitching of a vehicle body, and enhancement of riding comfortability. <P>SOLUTION: The suspension device 20 is provided with: a shock absorber 21; a cup member 30; a coil spring 22; a bump stopper 31; and an air spring mechanism 25. The cup member 30 is provided on a rod 28 of the shock absorber 21 and has a cylindrical shape opened in a cylinder 26 side end part. The coil spring 22 is provided between a wheel 11 and a vehicle body 10 and absorbs load. The bump stopper 31 is stored in the cup member 30, air-tightly closes an opening on the cylinder 26 side, and specifies an air spring chamber 39 between the cylinder 26 and it. The air spring mechanism 25 air-tightly seals the air spring chamber 39, and releases the air-tight state of the air spring chamber 39 when a load not less than a first predetermined value P1 is inputted from the bump stopper 31 or when a load not less than a second predetermined value P2 is inputted from the rod 28. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a suspension device including a spring member that is mounted on a vehicle and absorbs a load, and a shock absorber that attenuates vibration of the spring member.

  2. Description of the Related Art Conventionally, an automobile is provided with a suspension device in order to suppress absorption of a load input from a traveling road surface and rolling and pitching of a vehicle body.

  As an example of a suspension device, a strut suspension device has been proposed. The strut suspension device includes a shock absorber and a coil spring. The shock absorber includes a cylinder that stores oil as a working fluid, a piston that moves in the cylinder, and a rod. The piston is provided with a rod, which is fixed to the vehicle body side. The coil spring is disposed around the shock absorber.

  The strut suspension device configured as described above absorbs an impact by a coil spring when a load is input, and attenuates the vibration of the coil spring by a shock absorber.

  On the other hand, it has been proposed that the strut suspension supports a shock absorption by a coil spring and is provided with a bump stopper in order to effectively suppress rolling and pitching of an automobile.

  The bump stopper is provided around the rod of the shock absorber, and is disposed so that a predetermined gap is defined between the bump stopper and the cylinder of the shock absorber. For this reason, when a load is input from the road surface to the wheels of the automobile, the load first acts on the coil spring.

  As the coil spring contracts (the rod is pushed into the cylinder), the relative distance between the bump stopper and the cylinder decreases. When the coil spring contracts until the cylinder contacts the bump stopper (when the rod is pushed into the cylinder), the load also acts on the bump stopper.

  For this reason, the strut type suspension device including the bump stopper has a spring characteristic including a region where the impact acts only on the coil spring and a region where the impact acts on the coil spring and the bump stopper. As a spring characteristic of the suspension device, first, only the coil spring operates, and then the coil spring and the bump stopper operate.

The load absorbed by the strut-type suspension device relative to the rod stroke (the amount of movement of the rod) is such that the area where the coil spring and bump stopper act is more likely to rise than the area where only the coil spring acts. (For example, refer to Patent Document 1).
Patent No. 3444393

  While the automobile is traveling, an obstacle such as a stone may be picked up. In such a case, a load acts on the suspension device instantaneously. In consideration of such a situation, when improving the ride comfort of an automobile, it is required that the impact acting on the vehicle body be absorbed smoothly. (It is required that the amount of stroke of the rod with respect to the load is large.) Therefore, in order to improve the riding comfort, it is preferable that the region where only the coil spring operates is wide.

  Since the region in which only the coil spring operates is wide, even if the automobile rides on an obstacle as described above, the impact generated at this time is smoothly absorbed by the coil spring.

  On the other hand, in order to suppress rolling and pitching of the vehicle body, it is better that the suspension device be displaced with respect to the acting load (the rod stroke amount with respect to the load is required to be small). This is to prevent the vehicle body from greatly shaking with respect to the load caused by rolling or pitching. Therefore, in order to suppress rolling and pitching acting on the vehicle body, it is preferable that the area where only the coil spring operates is small and the area where the coil spring and the bump stopper operate is wide.

  Since the area in which only the coil spring operates is small and the area in which the coil spring and bump stopper operate is wide, even if the vehicle body shakes, the vibration is suppressed early by the bump stopper. .

  However, when the ride comfort is sought, the region in which only the coil spring operates is widened, and therefore it becomes difficult to suppress rolling and pitching. Further, if the area where only the coil spring operates to reduce rolling and pitching and the area where the coil spring and the bump stopper operate are widened, the riding comfort becomes worse. For this reason, it is difficult to achieve both suppression of rolling and pitching and enhancement of ride comfort.

  For this reason, the suspension device can change the spring characteristics of the suspension device according to the type of input load (for example, it can be switched to an appropriate spring characteristic depending on whether an obstacle is climbed or rolling or pitching). A control system has been proposed. However, the structure using this type of suspension electronic control system increases the cost.

  Accordingly, an object of the present invention is to provide a suspension device having a simple structure while achieving both suppression of rolling and pitching of the vehicle body and improvement of riding comfort.

  The suspension device of the present invention includes a shock absorber, a cup member, a spring member, a bump stopper, and a seal mechanism. The shock absorber is fixed to the wheel side and accommodates a working fluid inside, a piston movably accommodated in the cylinder, one end connected to the piston and the other end to the outside. And a rod fixed to the vehicle body side, and the piston absorbs the load by moving in the cylinder with respect to the input load. The cup member is provided on the opposite side of the rod from the cylinder and has a cylindrical shape with an open end on the cylinder side. The spring member is provided between the wheel and the vehicle body and absorbs an input load. The bump stopper is provided on the rod and accommodated in the cup member. The bump stopper includes a lid portion and a space defining portion. The lid portion slidably contacts the inner surface of the cup member so as to airtightly close the opening on the cylinder side, and a predetermined interval is defined between the lid portion and the cylinder. The space defining portion defines a gas chamber between the inner surface of the cup member. The bump stopper absorbs the load by being deformed with respect to the load input from the cylinder. The sealing mechanism hermetically seals a gas chamber defined between the bump stopper and the cup member, and when a load greater than a first predetermined value is input from the bump stopper or from the rod. When a load greater than a predetermined value of 2 is input, the airtight state of the gas chamber is released.

  According to this structure, a spring characteristic corresponding to the type of input load can be obtained. This point will be specifically described.

  When a load is momentarily input to the suspension device, the rod transmits the load to the seal mechanism without greatly entering the cylinder. As a result, since the sealed state of the gas chamber is released, the load is absorbed by the spring member.

  Further, when a load is gently input to the suspension device, the spring member is first bent by the load. Next, the cylinder comes into contact with the bump stopper. Then, a load is transmitted to the seal mechanism via the bump stopper.

  At this time, if the load is smaller than the first predetermined value, the sealed state of the gas chamber is not released. Therefore, in the suspension device, the load acts on the spring member, the bump stopper, and the gas chamber. Becomes higher.

  Thus, the load transmission path to the seal mechanism differs depending on whether the load is input instantaneously or slowly, and the release load value of the gas chamber is set corresponding to each transmission path. By setting, a spring characteristic matched to the type of load can be obtained.

  Also, no special control system is used to change the spring characteristics.

  In addition, the first predetermined value is set to a value smaller than the load value input due to rolling and pitching obtained by experiment or the like, and the second predetermined value is determined by an experiment or the like. By setting an instantaneous load input value when an object is picked up, it is possible to effectively achieve both suppression of rolling and pitching of the vehicle body and improvement of riding comfort.

  In a preferred embodiment of the present invention, the sealing mechanism includes a support wall portion, a ring member, a disc spring member, a first projection portion, and a second projection portion. The support wall portion is provided on the cup member and extends toward the rod. The ring member has an annular shape, and the rod is inserted into the inside, and is disposed between the support wall portion and the bump stopper, and a slit that penetrates from the bump stopper side toward the rod side is formed. Is done. The disc spring member is annular and inserts the rod inside, and is disposed between the ring member and the bump stopper, and hermetically closes the portion on the bump stopper side in the slit. The first protrusion is provided on the bump stopper side and abuts against the disc spring member, and the abutting portion is located on the rod side with respect to the inner edge of the ring member. The second projecting portion is provided on the rod side and abuts against the disc spring member, and the abutting portion is positioned closer to the rod than the abutting portion between the projecting portion and the disc spring member. The support wall portion, the ring member, the disc spring member, and the first protrusion are in airtight contact with each other to hermetically seal the gas chamber, and a load equal to or greater than the first predetermined value is applied to the gas chamber. When the disc spring member is input from the first protrusion, the closed state of the slit is released by changing the posture of the disc spring member, and a load of the second predetermined value or more is applied to the second spring member. When the disc spring member is inputted from the projection, the disc spring member is deformed, so that the closed state of the slit is released.

  According to this structure, the distance from the inner edge to the second protrusion is set larger than the distance from the inner edge of the ring member to the first protrusion. For this reason, the 2nd predetermined value which is a load value required in order for a disk spring member to deform | transform until the sealing state of a gas chamber is cancelled | released may be smaller than a 1st predetermined value.

  As a result, when a load is input instantaneously, even if the load is small, it is absorbed by the coil spring, so that the ride comfort of the vehicle body is improved.

  The first protrusion may be formed integrally with the bump stopper. Alternatively, it may be formed integrally with the disc spring member. Alternatively, the bump stopper and the disc spring member may be separate and may be sandwiched between the bump stopper and the disc spring member.

  Similarly, the second protrusion may be formed integrally with the rod. Alternatively, it may be a separate body from the rod.

  ADVANTAGE OF THE INVENTION According to this invention, while suppressing rolling and pitching of a vehicle body and improving a riding comfort, a suspension device having a simple structure can be provided.

  A suspension device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the vicinity of a strut suspension device 20 in an automobile on which a strut suspension device 20 which is an example of a suspension device is mounted.

  As shown in FIG. 1, the strut type suspension device 20 is installed, for example, one on each of the left and right front wheels of an automobile (showing a part of the strut house 10 of the vehicle body). FIG. 1 shows a strut type suspension device 20 installed on the left front wheel 11, for example.

  The strut suspension device 20 is provided between the front wheel 11 and the vehicle body (the strut house 10). The strut suspension device 20 has a function of absorbing a load input via the front wheel 11 and suppressing rolling and pitching of the vehicle body.

  The strut suspension device 20 includes a shock absorber 21, a coil spring 22, an upper spring seat 23, a lower spring seat 24, and an air spring mechanism 25.

  The shock absorber 21 includes a cylinder 26, a piston 27, and a rod 28.

  The cylinder 26 is connected to the front wheel 11 by the steering knuckle 12. Oil is accommodated in the cylinder 26 as a working fluid.

  The piston 27 is accommodated in the cylinder 26. Therefore, the piston 27 is indicated by a dotted line in the figure. The piston 27 is formed with an orifice (not shown). As the piston 27 moves through the cylinder 26, the oil passes through the orifice. Therefore, the kinetic energy of the piston 27 is consumed by the friction between the orifice and the oil.

  One end 28 a of the rod 28 is fixed to the piston 27, and the other end 28 b extends from the cylinder 26. Therefore, the posture of the rod 28 is displaced relative to the cylinder 26 as the piston 27 moves. The other end 28 b of the rod 28 is fixed to the strut house 10 of the vehicle body via the insulator 14.

  The insulator 14 includes an upper plate 100 having a disk shape, a lower plate 101 having a disk shape, a rubber member 102, and a support plate 103. The upper plate 100 and the lower plate 101 overlap each other. The central part of the upper plate 100 and the lower plate 101 bulges away from each other.

  The rubber member 102 is provided between the upper plate 100 and the lower plate 101. The support plate 103 is supported by the rubber member 102. The upper plate 100 and the lower plate 101 are formed with through holes 104 through which the other end portion 28 b of the rod 28 passes. The support plate 103 is formed with a connection hole 105 to which the other end 28b of the rod 28 is connected.

  The upper plate 100 and the lower plate 101 are fixed to the wall portion of the strut house 10 using bolts 106 and nuts 107. The rod 28 is connected to the vehicle body (the strut house 10) by having the other end 28b inserted into the insulator 14 and inserted into the connection hole of the support plate 103 and fixed to the support plate by the connection bolt 108. .

  The upper spring seat 23 has an annular shape, and the other end 28b of the rod 28 is inserted inside. The upper spring seat 23 has a concave shape that extends outward in the circumferential direction of the rod 28 and opens toward the cylinder 26 (downward).

  The upper spring seat 23 is disposed on the cylinder 26 side (downward) with respect to the lower plate 101 of the insulator 14. A holding plate 109 and a bearing 110 are sandwiched between the upper spring seat 23 and the lower plate 101. The bearing 110 is fixed to the upper spring seat 23. The holding plate 109 is fixed to the bearing 110. The holding plate 109 is fixed to the lower plate 101. Therefore, the upper spring seat 23 is indirectly fixed to the strut house 10.

  The lower spring seat 24 is fixed to the middle part of the cylinder 26. The lower spring seat 24 has a concave shape that extends outward in the circumferential direction of the cylinder 26 and opens toward the other end 28 b side (upward) of the rod 28.

  The coil spring 22 is interposed between the upper spring seat 23 and the lower spring seat 24. The coil spring 22 is disposed so as to accommodate the shock absorber 21 inside. An upper support portion 23 a is formed on the periphery of the upper spring seat 23 so as to support the upper end portion 22 a of the coil spring 22. The upper support portion 23 a is formed in a concave cross section so as to follow the shape of the upper end portion 22 a of the coil spring 22.

  The lower spring seat 24 is formed with a lower support portion 24 a that supports the lower end portion 22 b of the coil spring 22. The lower support portion 24 a is formed in a concave cross section so as to follow the shape of the lower end portion 22 b of the coil spring 22. The coil spring 22 is an example of a spring member referred to in the present invention.

  FIG. 2 is an enlarged cross-sectional view showing a range F2 indicated by a two-dot chain line in FIG. FIG. 2 shows the air spring mechanism 25. As shown in FIG. 2, the air spring mechanism 25 includes a cup member 30, a bump stopper 31, a ring member 37, and a disc spring member 32.

  The cup member 30 is provided around the rod 28. The cup member 30 is, for example, cylindrical. The cup member 30 is installed coaxially with the rod 28, for example. The cup member 30 is not limited to be installed coaxially with the rod 28.

  The lower end 30a on the cylinder 26 side of the cup member 30 is located at a position spaced apart from the cylinder 26 along the rod 28 by a predetermined distance (in a state where no load is input to the strut suspension device 20). The lower end 30a is open. As shown in FIG. 1, the upper end portion 30 b of the cup member 30 located on the side opposite to the cylinder 26 is fixed to the upper spring seat 23.

  As shown in FIG. 2, the bump stopper 31 has a cylindrical shape. The bump stopper 31 is fixed to the rod 28 by inserting the rod 28 inside thereof, and is accommodated inside the cup member 30. The bump stopper 31 has a lower end portion 33, an intermediate portion 34, and an upper end portion 35, and has a predetermined length along the rod 28. The bump stopper 31 has a rod 28 fitted therein, but can slide with respect to the rod 28.

  The lower end 33 is an end of the bump stopper 31 on the cylinder 26 side. The lower end part 33 has an elastic part 33a and a low friction part 33b. The elastic portion 33 a is made of rubber, for example, and extends to the vicinity of the inner surface 36 of the cup member 30 toward the outer side in the circumferential direction of the rod 28.

  The low friction part 33b is provided on the periphery of the elastic part 33a. As an example, the low friction part 33b is formed of a low friction resin. The low friction part 33b is in contact with the inner surface 36 of the cup member 30, and therefore hermetically seals the lower end opening of the cup member 30. The low friction portion 33b can slide while maintaining an airtight seal with respect to the inner surface 36 of the cup member 30 as the rod 28 advances and retreats with respect to the cylinder 26. The material which comprises the low friction part 33b should just be able to make the friction between the inner surfaces 36 of the cup member 30 small. The lower end portion 33 functions as a lid portion referred to in the present invention.

  The intermediate portion 34 is a portion immediately above the lower end portion 33 in the bump stopper 31. The intermediate part 34 is made of rubber, for example, and is formed integrally with the elastic part 33a. The intermediate portion 34 is formed in a bellows shape along the direction in which the rod 28 extends. By forming the intermediate portion 34 in a bellows shape, even when a load is input to the bump stopper 31, the intermediate portion 34 is easily deformed with respect to the load.

  A gap S is defined between the outer peripheral surface 34 a of the intermediate portion 34 and the inner surface 36 of the cup member 30. The intermediate part 34 functions as a space defining part in the present invention.

  The upper end portion 35 is a portion immediately above the intermediate portion 34 in the bump stopper 31. The upper end portion 35 is made of rubber and is formed integrally with the elastic portion 33a. The upper end portion 35 is located in the vicinity of the upper end portion 35 of the cup member 30. The upper end 35 extends to the vicinity of the inner surface 36 of the cup member 30 toward the outer side in the circumferential direction. The upper end portion 35 is not in contact with the inner surface 36. The upper end part 35 functions as a space defining part in the present invention.

  2 shows a cross section of the bump stopper 31, but the bump stopper 31 has a shape in which the cross sectional shape shown in FIG. 2 is continuous in the circumferential direction.

  FIG. 3 is a perspective view showing a state in which the air spring mechanism 25 is disassembled. As shown in FIGS. 2 and 3, the ring member 37 has a ring shape, and the rod 28 is inserted through the ring member 37. The ring member 37 is disposed between the upper end portion 30 b of the cup member 30 and the bump stopper 31.

  The upper end portion 30b of the cup member 30 has an upper end wall 30c extending inward to the vicinity of the rod 28. The rod 28 is inserted into the opening 30d of the upper end wall 30c. As shown in FIG. 2, a gap is defined between the inner edge 30 e of the opening 30 d and the rod 28. The upper end wall 30c is a support wall portion referred to in the invention.

  The inner edge 37a of the ring member 37 is located outside the inner edge 30e of the opening 30d of the upper end wall 30c. As shown in FIG. 3, a plurality of slits 38 are formed in the inner peripheral portion of the ring member 37. The slit 38 extends to the inner edge 37a.

  FIG. 4 is an enlarged cross-sectional view showing a range of F4 indicated by a two-dot chain line in FIG. FIG. 4 shows the periphery of the ring member 37 in an enlarged manner. As shown in FIG. 4, the ring member 37 has a rectangular cross section, and has a surface 37 b facing the bump stopper 31 and a surface 37 c facing the rod 28. The slit 38 is formed from the surface 37b to the surface 37c as shown by a dotted line in the figure, and is formed by cutting upward as it goes to the inner edge 37a. Therefore, the sectional shape of the slit 38 is substantially triangular.

  The ring member 37 is not limited to a rectangular cross section. The slit 38 may be formed in the ring member 37 from the portion facing the bump stopper 31 to the portion facing the rod 28.

  The ring member 37 is made of rubber, for example, and has elasticity that can be deformed with respect to a predetermined load. In the present embodiment, as shown in FIG. 3, the slits 38 are arranged at equal intervals in the circumferential direction, but the present invention is not limited to this.

  The disc spring member 32 is annular, and the rod 28 is inserted through the inside thereof. As shown in FIG. 4, the disc spring member 32 has a substantially uniform thickness from the outer edge to the inner edge. The opening 32a of the disc spring member 32 has a shape in which the rod 28 is substantially fitted. The disc spring member 32 is slidable with respect to the rod 28. The disc spring member 32 is sandwiched between the ring member 37 and the bump stopper 31. As shown in FIG. 2, the disc spring member 32 is in contact with the ring member 37 and is in contact with the bump stopper 31.

  The disc spring member 32 has a size that covers the slit 38. That is, the outer edge 32 b of the disc spring member 32 is located outside each slit 38. In the ring member 37 shown in FIG. 3, the position where the outer edge 32b of the disc spring member 32 abuts is indicated by a two-dot chain line. Each slit 38 is airtightly closed by the disc spring member 32 from the bump stopper side.

  As described above, the ring member 37 is made of rubber and has elasticity, and the disc spring member 32 is pressed against the ring member 37 so as to airtightly close the slit 38. In the present embodiment, since the ring member 37 is an elastic rubber member, the slit 38 is effectively blocked.

  As described above, each slit 38 is airtightly closed, so that the range from the lower end 33 of the bump stopper 31 to the ring member 37 in the cup member 30 (the gap S, between the upper end 35 and the inner surface 36). The air spring chamber 39 is hermetically closed. The air spring chamber 39 is a gas chamber referred to in the present invention. Air is an example of a gas referred to in the present invention.

  A plurality of protrusions 40 are formed on the upper end portion 35 of the bump stopper 31. The protrusion 40 is disposed on the upper end surface of the upper end 35 that faces the disc spring member 32. A plurality of protrusions 40 are arranged on the upper end portion 35 at equal intervals in the circumferential direction around the rod 28. The protrusion 40 is in contact with the disc spring member 32.

  As shown in FIG. 2, the protrusion 40 is formed in a substantially hemispherical shape whose cross section protrudes toward the disc spring member 32. The protrusion 40 is in contact with the disc spring member 32 at its apex 41. The vertex 41 is located on the inner side (the rod 28 side) than the inner edge 37 a of the ring member 37. The protrusion 40 is an example of a first protrusion referred to in the present invention.

  A ring portion 42 is formed on the rod 28. The ring portion 42 protrudes outward in the circumferential direction from the peripheral surface of the rod 28, and supports the disc spring member 32 by abutting from the cylinder 26 side. The disc spring member 32 is made of an elastically deformable material, and is made of, for example, iron. The ring portion 42 is an example of a second protrusion portion referred to in the present invention.

  2 and 4 show a state in which no load is input to the strut suspension device 20, and therefore a state in which no load is input to the disc spring member 32.

  The disc spring member 32 elastically deforms its posture by a load input from the protrusion 40 or a load input from the ring portion 42. When the disc spring member 32 is deformed, the closed state of the slit by the disc spring member 32 is released. That is, the sealed state of the air spring chamber 39 is released.

  The deformation of the disc spring member 32 will be described in detail. FIG. 5 is a side view showing a state where the rod 28 has entered the cylinder 26 until the cylinder 26 contacts the bump stopper 31. As shown in FIG. 5, when the coil spring 22 contracts and the position of the cylinder 26 rises and the cylinder 26 comes into contact with the bump stopper 31, a load is applied to the bump stopper 31 and the protrusion 40 of the bump stopper 31 is moved. A load acts on the disc spring member 32 through the via.

  FIG. 6 is an enlarged cross-sectional view showing a state in which a load is input from the protrusion 40 to the disc spring member 32 as described above. As shown in FIG. 6, a moment Ma that promotes deformation in the direction indicated by the arrow acts on the disc spring member 32 around the inner edge 37 a of the ring member 37. The moment Ma at this time is represented by the product of the total value of the loads input from the protrusions 40 and the distance L1 from the inner edge 37a to the vertex 41 of the protrusion 40.

  When a load greater than or equal to the first predetermined value P1 is input to the disc spring member 32 via the protrusion 40, the rod 28 side of the disc spring member 32 is deformed in the acting direction of the load relative to the inner edge 37a. Then, the portion of the disc spring member 32 opposite to the rod 28 across the inner edge 37 a (the portion that closed each slit 38 in the disc spring member 32) is separated from the ring member 37. Since the protrusion 40 is hemispherical, the disc spring member 32 is smoothly deformed. The first predetermined value P1 referred to here is a total value of inputs from all the protrusions 40.

  As a result, the closed state of each slit 38 is released and the sealed state of the air spring chamber 39 is released. When a load less than the first predetermined value P <b> 1 is input through each protrusion 40, the closed state of each slit 38 is not released, and therefore the air spring chamber 39 is kept sealed. The first predetermined value P1 referred to in the present invention will be described in detail later.

  FIG. 7 shows a state in which a load is instantaneously applied to the strut suspension device 20. In the shock absorber 21, the rod 28 does not enter the cylinder 26 with respect to a load that acts instantaneously.

  Therefore, when a load momentarily acts on the strut suspension device 20, the load is input to the disc spring member 32 via the ring portion 42 of the rod 28.

  FIG. 8 is an enlarged cross-sectional view showing a state in which a load is input to the disc spring member 32 through the ring portion 42 as described above. As shown in FIG. 8, when a load is input from the ring portion 42 to the disc spring member 32, a moment Mb indicated by an arrow acts around the inner edge 37 a of the ring member 37. The moment Mb is represented by the product of the total load input from the ring portion 42 and the distance L2 from the inner edge 37a of the ring member 37 to the ring portion 42.

  When the load input from the ring portion 42 is equal to or greater than the second predetermined value P2, the rod 28 side of the disc spring member 32 is deformed in the direction of the load with respect to the inner edge 37a. Then, the portion of the disc spring member 32 opposite to the rod 28 across the inner edge 37 a (the portion that closed each slit 38 in the disc spring member 32) is separated from the ring member 37. When the disc spring member 32 is separated from the ring member 37, the closed state of each slit 38 is released and the airtight state of the air spring chamber 39 is released.

  Since the disc spring member 32 is deformed and the position of the rod 28 is changed (because the rod 28 is moved upward by the deformation of the disc spring member 32), the lower spring seat 24 and the upper spring seat 23 approach each other. Therefore, the coil spring 22 is also contracted with the deformation of the disc spring member 32.

  Therefore, the second predetermined value P2 is a load necessary for deforming only the disc spring member 32 until the closed state of each slit 38 is released, and a load necessary for deforming the coil spring 22 at this time. And the total value. The second predetermined value P2 will be described in detail later.

  The air spring mechanism 25 functions as a sealing mechanism in the present invention.

  Next, the operation of the strut type suspension device 20 will be described. First, an operation when an automobile rides on an obstacle such as a stone will be described. When the automobile rides on an obstacle, a load is instantaneously applied to the strut suspension device 20 via the wheels 11.

  In the strut type suspension device 20, the rod 28 does not enter the cylinder 26 as shown in FIGS. 7 and 8 with respect to the momentarily input load, and therefore, the relative posture of the rod 28 with respect to the cylinder 26. Will not change significantly.

  As a result, due to the load input to the strut suspension device 20, the shock absorber 21 and the lower spring seat 24 fixed to the shock absorber 21 are displaced upward while maintaining their relative positions.

  For this reason, the load acts on the insulator 14 via the rod 28. In the insulator 14, the rubber member 102 is deformed by the load. Therefore, the positions of the shock absorber 21 and the lower spring seat 24 are displaced upward as the insulator 14 is deformed.

  At this time, since the upper spring seat 23 is fixed to the strut house 10, the positions of the strut house 10, the cup member 30, the ring member 37, and the disc spring member 32 do not change.

  For this reason, the relative positions of the upper spring seat 23 and the lower spring seat 24 are displaced so as to approach each other. Further, the relative position of the disc spring member 32 with respect to the rod 28 also changes. With the change in the relative posture between the upper spring seat 23 and the lower spring seat 24 and the change in the relative posture of the rod 28 with respect to the disc spring member 32, the coil spring 22 contracts and the disc spring member 32 via the ring portion 42. Load is input to. When the second predetermined value P2 acts on the disc spring member 32 via the ring portion 42, the disc spring member 32 is deformed.

  The second predetermined value P2 referred to in the present embodiment is a load value that is input when the automobile rides on an obstacle such as a stone, and is obtained through an experiment or the like.

  With the deformation of the disc spring member 32, the portion of the disc spring member 32 that covers each slit 38 is separated from the ring member 37. As a result, the closed state of each slit 38 is released, and the airtight state of the air spring chamber 39 is released.

  As described above, when a load greater than or equal to the second predetermined value P2 is instantaneously applied to the strut suspension device 20, the air spring chamber 39 is released from the sealed state, so that the load is absorbed only by the coil spring 22. .

  FIG. 9 is a graph showing the spring characteristics of the strut suspension device 20. The graph shown by the solid line in the figure shows the spring characteristics of the strut suspension device 20 when a load is instantaneously applied as described above. In the drawing, the horizontal axis indicates the amount of deformation (contraction amount) of the coil spring 22, and the vertical axis indicates the load value input to the strut suspension device 20.

  As shown in FIG. 9, when a load greater than or equal to the second predetermined value P2 is instantaneously applied, the load is first absorbed only by the coil spring 22, so that the spring characteristics are relatively low.

  As described above, since the spring characteristic is low with respect to the impact when riding on an obstacle, the impact is efficiently absorbed. As a result, the ride comfort is improved.

  Further, as shown in FIG. 9, even when the load is instantaneously input, when the displacement of the shock absorber 21 is large (the relative positional relationship between the cylinder 26 and the rod 28 does not input the load). The cylinder 26 abuts against the bump stopper 31 while the airtight state of the air spring chamber 39 is released.

  For this reason, after the cylinder 26 abuts against the bump stopper 31, the load is absorbed by the coil spring 22 and the bump stopper 31. In the region where the load acts on the coil spring 22 and the bump stopper 31, the spring characteristics are high.

  As shown in FIG. 9, in the strut type suspension device 20, the region where only the coil spring 22 operates and the region where the coil spring 22 and the bump stopper 31 operate are set so as to give priority to the riding comfort of the automobile. ing. That is, the region in which the coil spring 22 operates is small, and the spring characteristics of the bump stopper 31 are set in consideration of riding comfort (soft for riding comfort).

  Next, the operation of the strut type suspension device 20 when rolling or pitching occurs in the vehicle body will be described.

  When rolling or pitching occurs in the vehicle body, the posture of the vehicle body changes. Due to this posture change, a load is input to the strut suspension device 20. The posture change of the vehicle body due to rolling or pitching is gentle and relatively small. Therefore, no load is instantaneously input to the strut type suspension device 20.

  For this reason, in the strut type suspension device 20, the coil spring 22 is contracted by the input load. When the coil spring 22 contracts until the cylinder 26 abuts against the bump stopper 31, a load is input to the disc spring member 32 via the protrusion 40 of the bump stopper 31 as shown in FIGS.

  Here, the first predetermined value will be specifically described. As described above, when a load greater than or equal to the first predetermined value P1 is input to the disc spring member 32 via the protrusion 40, the disc spring member 32 is positioned to release the sealed state of the air spring chamber 39. Deforms until. The first predetermined value P1 is set to a value larger than the load input to the disc spring member 32 due to rolling or pitching of the vehicle body. The first predetermined value P1 is obtained in advance by an experiment for detecting a load caused by rolling or pitching.

  Therefore, when a load is input due to rolling or pitching (when the load is less than the first predetermined value P1), the closed state of each slit 38 is not released, and therefore the air spring chamber 39 Sealed state is maintained. For this reason, the strut type suspension device 20 operates with the coil spring 22, the bump stopper 31, and the air spring (the air spring chamber 39 functions as an air spring) for rolling and pitching. It has characteristics.

  As described above, since the region where only the coil spring 22 operates is set to be small, the coil spring 22, the bump stopper 31 and the air spring chamber 39 operate for rolling and pitching. Rolling and pitching are suppressed.

  FIG. 10 is a graph showing the spring characteristics of the strut type suspension device 20 when a load is gently applied, for example, when rolling or pitching is applied to the vehicle body. The spring characteristic of the strut type suspension device 20 when the load acts gently is indicated by a solid line.

  Note that the term “relaxed” as used herein refers to the speed of input of a load that allows the rod 28 to enter the cylinder 26 when a load is applied.

  When the load input to the disc spring member 32 via the protrusion 40 becomes equal to or higher than the first predetermined value P1, the sealed state of the air spring chamber 39 is released so that the coil spring 22 and the bump stopper 31 act. become.

  In the strut type suspension device 20 configured as described above, as described above, the portion where the load is input to the disc spring member 32 differs depending on the load input speed (instantaneous, moderate), in other words, depending on the type of load.

  Specifically, when a load is input instantaneously, a load is input from the ring portion 42, and when a load is input slowly, a load is input from the protrusion 40.

  For this reason, the release of the sealed state of the air spring chamber 39 differs depending on the instantaneous load input when an obstacle is climbed and the load input caused by rolling and pitching. The strut suspension device 20 uses appropriate spring characteristics in each case.

  Therefore, since a separate control system or the like is not required for switching the spring characteristics, the strut type suspension device 20 has both a suppression of rolling and pitching of the vehicle body and an improvement in riding comfort and a simple structure. .

  In addition, the first predetermined value is set to a value smaller than a load value input due to rolling and pitching obtained by experiment or the like, and the second predetermined value is determined by an experiment or the like. By setting an instantaneous load input value when an object is picked up, it is possible to effectively achieve both suppression of rolling and pitching of the vehicle body and improvement of riding comfort.

  In addition, by setting the coil spring 22 and the bump stopper 31 in consideration of riding comfort (setting the region where only the coil spring 22 operates is small and the spring characteristics of the bump stopper 31 are small), rolling and pitching can be performed. It is possible to efficiently achieve both suppression of the vehicle and improvement of ride comfort.

  Further, L2 is set to be larger than L1 in the distance L1 from the inner edge 37a of the ring member 37 to the contact portion (vertex portion 41) in the protrusion 40 and the distance L2 from the inner edge 37a to the ring part 42.

  For this reason, the second predetermined value P2 that is a load value necessary for the disc spring member 32 to be deformed until the sealed state of the air spring chamber 39 is released may be smaller than the first predetermined value P1. .

  As a result, when a load is instantaneously input, the coil spring 22 absorbs the load even if the load is small, so that the ride comfort is improved.

1 is a cross-sectional view showing the vicinity of a strut suspension device in an automobile on which a strut suspension device according to an embodiment of the present invention is mounted. Sectional drawing which expands and shows the range of F2 shown with a dashed-two dotted line in FIG. The perspective view which shows the state by which the air spring mechanism shown by FIG. 2 was decomposed | disassembled. Sectional drawing which expands and shows the range of F4 shown with a dashed-two dotted line in FIG. Sectional drawing which shows the state which the rod entered in the cylinder until the cylinder shown by FIG. 2 contact | abuts to a bump stopper. Sectional drawing which expands and shows the state into which the load was input into the disk spring member from the projection part shown by FIG. FIG. 3 is a cross-sectional view showing a state in which a load is instantaneously applied to the strut suspension device shown in FIG. 2. Sectional drawing which expands and shows the state into which the load was input into the disk spring member via the ring part shown by FIG. The graph which shows the spring characteristic when a load is momentarily input into the strut type suspension device of this embodiment. The graph which shows the spring characteristic when a load is gently input into the strut type suspension device of the present embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Strut house (vehicle body), 11 ... Front wheel (wheel), 21 ... Shock absorber, 22 ... Coil spring (spring member), 25 ... Air spring mechanism (seal mechanism), 26 ... Cylinder, 27 ... Piston, 28 ... Rod 30 ... Cup member, 30c ... Upper end wall (support wall portion), 31 ... Bump stopper, 32 ... Belleville spring member, 33 ... Lower end portion (lid portion), 34 ... Intermediate portion (space defining portion), 35 ... Upper end portion (Space defining part), 37 ... ring member, 38 ... slit, 39 ... air spring chamber (gas chamber), 40 ... projection (first projection), 42 ... ring (second projection)

Claims (2)

A cylinder that is fixed to the wheel side and accommodates the working fluid inside, a piston that is movably accommodated in the cylinder, and one end connected to the piston and the other end to the outside and fixed to the vehicle body side A shock absorber that absorbs the load as the piston moves in the cylinder with respect to the input load;
A cylindrical cup member that is provided on the opposite side of the rod in the rod and that has an opening on the cylinder side end;
A spring member provided between the wheel and the vehicle body for absorbing an input load;
A bump stopper provided on the rod and accommodated in the cup member, slidably abutting the inner surface of the cup member to seal the cylinder side opening in an airtight manner and a predetermined gap between the cylinder and the cylinder And a space defining portion that defines a gas chamber between the inner surface of the cup member and absorbs the load by being deformed with respect to the load input from the cylinder. Bump stopper,
The gas chamber defined between the bump stopper and the cup member is hermetically sealed, and when a load greater than a first predetermined value is input from the bump stopper or a second predetermined value from the rod A suspension device comprising: a sealing mechanism that releases the airtight state of the gas chamber when the above load is input. The sealing mechanism is
A support wall provided on the cup member and extending toward the rod;
A ring member that is annular and that is inserted between the rod and disposed between the support wall portion and the bump stopper, and is formed with a slit penetrating from the bump stopper side toward the rod side; ,
A disc spring member that is annular and passes through the rod inside and is disposed between the ring member and the bump stopper, and airtightly closes the portion on the bump stopper side in the slit;
A first protrusion which is provided on the bump stopper side and abuts against the disc spring member, the abutting portion being located on the rod side of the inner edge of the ring member;
A second projecting portion provided on the rod side and in contact with the disc spring member, the abutting portion being positioned on the rod side with respect to the abutting portion between the projecting portion and the disc spring member. ,
The support wall portion, the ring member, the disc spring member, and the first protrusion are in airtight contact with each other to hermetically seal the gas chamber, and a load equal to or greater than the first predetermined value is applied to the gas chamber. When the disc spring member is input from the first protrusion, the closed state of the slit is released by changing the posture of the disc spring member, and a load of the second predetermined value or more is applied to the second spring member. The suspension device according to claim 1, wherein when the disc spring member is input from a protrusion, the disc spring member is deformed to release the closed state of the slit.

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