WO2019230190A1

WO2019230190A1 - Shock absorber

Info

Publication number: WO2019230190A1
Application number: PCT/JP2019/015088
Authority: WO
Inventors: 理一永尾; 浩一山香; 喜裕山口; 孝幸大野; 友樹菊池
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2018-05-31
Filing date: 2019-04-05
Publication date: 2019-12-05
Also published as: JP6994434B2; JP2019210951A

Abstract

The purpose of the present invention is to provide a shock absorber which ensures provision of strength and which can be made light-weight. In the present invention, a tubular outer cylinder 113 for housing a damping mechanism has a pair of knuckle attachment parts 104a, 104b protruding in one direction from the exterior surface of the outer cylinder 113 and being provided integrally with the outer cylinder 113. The knuckle attachment parts 104a, 104b have respective wide-width surfaces facing each other, and the wide-width surfaces are provided along the axial direction of the outer cylinder 113. When the thickness of the outer cylinder 113 on the sides of the knuckle attachment parts 104a, 104b on a virtual line connecting the central axis of the outer cylinder 113 and the middle point between the two facing surfaces of the knuckle attachment parts 104a, 104b is defined as ta, and the thickness of the outer cylinder 113 on the opposite sides of the knuckle attachment parts 104a, 104b across the central axis of the outer cylinder 113 is defined as tc, the outer cylinder 113 is configured to have a thick wall part that satisfies the relation: ta>tc.

Description

Shock absorber

The present invention relates to a shock absorber.

The shock absorber used in the McPherson strut suspension of an automobile has a piston provided with a damping valve housed in an inner cylinder, and slides in the inner cylinder along the axial direction. An outer cylinder that forms a reservoir chamber is disposed on the outer peripheral side of the inner cylinder. A recent shock absorber is mainly a double cylinder type having an inner cylinder and an outer cylinder. The front end and bottom end of the inner cylinder and outer cylinder are connected by a rod guide and a bottom valve, respectively. The piston is fixed to the bottom end side of the piston rod that passes through the rod guide, the tip end of the piston rod is connected to the vehicle body side, and the bottom side of the outer cylinder is connected to the knuckle of the wheel. The double-cylinder strut-type shock absorber supports the vehicle body posture with respect to the vehicle body weight and the vehicle body tilt as a vehicle column, and attenuates vibration during driving to improve the riding comfort.

Since the strut type shock absorber supports the vehicle body posture with respect to the vehicle body weight and the vehicle body tilt as a vehicle column, strength is required for the mounting portion with the vehicle body. In particular, the knuckle attachment portion provided on the outer periphery of the outer cylinder connected to the wheel knuckle is required to have strength against bending moment. In response to the above requirements, for example, a shock absorber has been proposed in which an outer cylinder is formed in an oval shape to ensure strength (for example, Patent Document 1).

On the other hand, recent automobiles are required to be lighter in order to improve fuel efficiency in consideration of environmental impact. In response to this requirement, a shock absorber in which the outer cylinder is formed of a light metal such as aluminum has been proposed (for example, Patent Document 2).

JP 2002-89606 A Japanese Patent Laid-Open No. 4-158946

In the technology described in Patent Document 1, although consideration is given to securing the strength of the shock absorber, weight reduction is not considered at all. For this reason, the technique described in Patent Document 1 is unsuitable for improving fuel consumption by reducing the weight of the vehicle body required in recent automobiles.

Further, in the technique described in Patent Document 2, although weight reduction is taken into consideration, the strength securing at the time of mounting the vehicle body and the wheel is insufficient.

The tensile strength of aluminum alloy material is about one-half that of steel material. For this reason, in order to secure the necessary strength against the lateral force generated in the vehicle interior and exterior direction and the vehicle body longitudinal direction, the outer diameter of the outer cylinder must be increased and the wall thickness increased, and the light weight due to the use of aluminum alloy material The advantage of conversion was lost.

An object of the present invention is to provide a shock absorber capable of solving the above-described problems, ensuring strength and reducing the weight.

In order to achieve the above object, a feature of the present invention is that a shock having a piston, a shock absorbing mechanism having a piston rod connected to the piston, and a cylindrical housing that houses the shock absorbing mechanism. In the absorber, the housing is provided integrally with the housing, and has a pair of knuckle mounting portions protruding in one direction from the outer surface of the housing, and the pair of knuckle mounting portions face the wide surfaces, respectively. The wide surface is provided along the axial direction of the casing, and the casing is configured to knuckle on an imaginary line connecting an intermediate surface between the pair of knuckle mounting portions and a central axis of the casing. the thickness of the housing of the mounting portion side is t _a, the thickness of the casing on the opposite side of the knuckle mounting portion with respect to the central axis of the housing in the case of a t _c, t _a> t the relationship of _c Mitsuru There to having to thick portion.

Further, the present invention is characterized by a piston, a piston rod connected to the piston, a cylindrical inner cylinder that accommodates the piston and the piston rod, an outer cylinder that accommodates the inner cylinder, The outer cylinder is provided integrally with the outer cylinder, and has a pair of knuckle attachment portions protruding in one direction from the outer surface of the outer cylinder, and the pair of knuckle attachment portions are each wide. The wide surfaces are provided along the axial direction of the outer cylinder, and a line passing through the intermediate point between the opposing surfaces of the pair of knuckle mounting portions and the cross-sectional center point of the inner cylinder is a first imaginary line. The first imaginary line is a line passing through the cross-sectional center point of the inner cylinder rotated about 45 ° clockwise around the cross-sectional center point of the inner cylinder as a second imaginary line, Orthogonal, cross section of the inner cylinder A vehicle body partitioned by the second imaginary line and the third imaginary line is defined as a third imaginary line passing through the center point, and a vehicle body outer side direction partitioned by the second imaginary line and the third imaginary line is defined as a virtual region I. The front side direction is a virtual region II, the rear side direction of the vehicle body partitioned by the second virtual line and the third virtual line is a virtual region III, and the vehicle body inner side partitioned by the second virtual line and the third virtual line When the direction is a virtual area IV, the minimum plate thickness of the outer cylinder in the virtual area I is t _a ′, and the minimum plate thickness of the outer cylinder in the virtual area IV is t _c ′, the outer cylinder Has _a thick portion that satisfies the relationship of t _a ′> t _c ′.

According to the present invention, it is possible to provide a shock absorber capable of ensuring strength and reducing weight.

1 is a schematic diagram of a suspension device according to an embodiment of the present invention. 1 is a vertical side view (including a partial vertical cross-sectional view) of a multi-cylinder strut type shock absorber as viewed from the front of a vehicle body according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG.

Hereinafter, embodiments of the shock absorber according to the present invention will be described with reference to the drawings. The present invention is not limited to the following examples, and includes various modifications and applications within the scope of the technical concept of the present invention.

In this embodiment, a case where the present invention is applied to a four-wheeled vehicle will be described as an example. In the present embodiment, an example in which a multi-cylinder strut type shock absorber is used as the shock absorber will be described. In the description of this embodiment, according to the coordinate axes described in the lower left of FIGS. 2 and 3, the X direction, the Y direction, and the Z direction are set, the arrow direction is positive (+), and the counter arrow direction is negative (−). Express.

FIG. 1 is a schematic view of a suspension device according to an embodiment of the present invention. FIG. 1 is a view of the vehicle as viewed from the front, and shows a front wheel located on the right side in the traveling direction of the vehicle.

In FIG. 1, the suspension device 100 is disposed between the vehicle body 200 and the wheels 300. The suspension device 100 includes a suspension coil spring 101 and a shock absorber 110 disposed in parallel with the suspension coil spring 101 and between the vehicle body 200 and the wheel 300. The shock absorber 110 includes a cylinder 102 and a piston rod 103. Further, a knuckle attachment portion 104 for connecting to the wheel 300 side is attached to the cylinder 102 of the shock absorber 110.

The wheel 300 is attached to the hub 301. The hub 301 is attached to a knuckle 302. By fixing the knuckle attachment portion 104 of the shock absorber 110 to the knuckle 302, the vehicle body 200 and the wheel 300 are connected via the shock absorber 110. A lower arm 303 is disposed below the knuckle 302. One end of the lower arm 303 is connected to the knuckle 302, and the other end of the lower arm 303 is connected to the vehicle body 200. The lower arm 303 suppresses front / rear and left / right forces applied to the wheel 300. The shock absorber 110 according to the present embodiment is disposed so as to incline toward the inside of the vehicle body 200 as the axis of the piston rod 103 is directed upward from below.

Next, the configuration of the shock absorber 110 according to the present embodiment will be described with reference to FIGS. FIG. 2 is a vertical side view (including a partial vertical cross-sectional view) of a multi-cylinder strut type shock absorber as viewed from the front of the vehicle body according to the embodiment of the present invention. 3 is a cross-sectional view taken along the line AA ′ of FIG.

The shock absorber 110 includes an inner cylinder 112 that slidably houses a piston 111 and an outer cylinder 113 that is disposed on the outer peripheral side of the inner cylinder 112. The inner cylinder 112 and the outer cylinder 113 constitute a cylinder 102. One end of a piston rod 103 is connected to the piston 111, and the piston 111 slides along the Y-axis direction in the inner cylinder 112 together with the piston rod 103. In this embodiment, the piston 111, the inner cylinder 112, and the piston rod 103 constitute a buffer mechanism.

The inner cylinder 112, the outer cylinder 113, and the piston rod 103 are arranged concentrically around the center line 400. A reservoir chamber 114 is formed between the inner cylinder 112 and the outer cylinder 113.

An oil seal 115 and a rod guide 116 are provided at the front end of the inner cylinder 112 and the outer cylinder 113 in the Y-axis direction. The distal end side of the outer cylinder 113 is molded with an axial length longer than that of the inner cylinder 112, and the oil seal 115 and the rod guide 116 are stored in this portion. The rod guide 116 is press-fitted and fixed at the tip end in the Y-axis direction of the inner diameter of the inner cylinder 112, fixes the inner cylinder 112 in the outer cylinder 113, and has an opening at the center to guide the piston rod 103. The piston rod 103 is provided so as to protrude from a hole 113 a formed at the tip of the outer cylinder 113. An integrated outer cylinder bottom plate 117 is molded at the bottom in the Y-axis direction. The outer cylinder bottom plate 117 is a bottom surface facing the piston 111. Similar to the distal end side, the axial length of the bottom side of the outer cylinder 113 is longer than the axial length of the inner cylinder 112. A bottom valve 118 is housed in the outer cylinder bottom plate 117 and is press-fitted and fixed to a bottom end portion inside the inner cylinder 112. The oil seal 115, the rod guide 116, the inner cylinder 112, and the bottom valve 118 are caulked and fixed by an outer cylinder tip plate 113b integrated with the Y-axis direction tip of the outer cylinder 113, and the oil seal 115, the rod guide 116, A compressive residual axial force transmitted in the order of the inner cylinder 112, the bottom valve 118, and the outer cylinder bottom plate 117 is applied. At this time, the inner cylinder 112 is filled with a liquid (not shown) such as oil, and the reservoir chamber 114 is filled with a predetermined amount of nitrogen gas (not shown) together with the liquid. Oil and nitrogen gas are sealed with an oil seal 115 fixed by caulking. The outer cylinder 113 functions as a cylindrical housing that houses the buffer mechanism.

The piston 111 is coupled to the bottom end of the piston rod 103 in the Y-axis direction. The tip of the piston rod 103 passes through the rod guide 116 and the oil seal 115 and extends to the tip of the outer cylinder 113 in the Y-axis direction, and is coupled to the vehicle body 200 (FIG. 1) via an anti-vibration rubber (not shown). ing.

A stabilizer bracket 119 for fastening a stabilizer rod (not shown) is integrally formed on the outer peripheral surface of the outer cylinder 113, and a spring seat 120 for supporting a suspension coil spring 101 (FIG. 1) (not shown) is press-fitted and fixed. A pair of knuckle attachment portions 104 (104a, 104b) that are fastened to the knuckle 302 (FIG. 1) are provided on the outer surface of the outer cylinder 113 on the bottom side. The knuckle attachment portion 104 (104a, 104b) is integrally molded with the outer cylinder 113 so as to be spaced apart in parallel in the X-axis direction and to protrude toward the −Z-axis direction side (one direction side), that is, toward the outer side of the vehicle body. ing. The knuckle attachment portions 104 (104 a and 104 b) face the wide surfaces, and the wide surfaces are provided along the axial direction of the outer cylinder 113.

The knuckle 302 of the wheel 300 is disposed between the knuckle mounting portion 104a and the knuckle mounting portion 104b that are spaced apart in the X-axis direction. Further, a plurality of bolt holes 105 (105a, 105b, 105c, 105d) are provided at locations where the knuckle mounting portion 104a and the knuckle mounting portion 104b are opposed to each other, and the knuckle 302 and the knuckle are bolted into the bolt holes. The attachment portion 104 is fastened, and the shock absorber 110 and the wheel 300 are connected.

The piston 111 housed in the inner cylinder 112 separates the inside of the inner cylinder 112 into an upper chamber 121 and a lower chamber 122. The piston 111 is provided with one or more piston orifices 111a, a piston check valve 123, and an extension side damping valve 124.

The damping force when the piston rod 103 strokes along the center line 400 in the extension direction (+ Y-axis direction) passes through the piston orifice 111a and the extension side damping valve 124 when the liquid flows from the upper chamber 121 into the lower chamber 122. The distribution resistance by doing is generated as a load.

When the piston rod 103 strokes along the center line 400 in the contraction direction (−Y-axis direction), the liquid is caused to flow from the lower chamber 122 through the piston orifice 111a into the upper chamber 121 by the piston check valve 123.

The bottom valve 118 is provided with one or more bottom valve orifices 118a, a bottom valve check valve 125, and a compression side damping valve 126. When the piston rod 103 strokes in the extending direction (+ Y-axis direction) along the center line 400, the liquid flows into the lower chamber 122 from the reservoir chamber 114 through the bottom valve orifice 118a by the bottom valve check valve 125. Be made.

The damping force when the piston rod 103 strokes in the contraction direction (−Y axis direction) along the center line 400 is such that when the liquid flows from the lower chamber 122 into the reservoir chamber 114, the bottom valve orifice 118 a and the compression side damping valve 126. Distribution resistance due to passing through is generated as a load.

Therefore, when the piston rod 103 strokes in the extending direction (+ Y-axis direction) along the center line 400, a damping force is generated by the piston orifice 111a of the piston 111 and the extension side damping valve 124, and at the same time, the piston rod 103 is retracted. Is replenished from the reservoir chamber 114 into the lower chamber 122 through the bottom valve check valve 125 of the bottom valve 118, and conversely, when the piston rod 103 strokes in the contraction direction (−Y-axis direction) along the center line 400, At the same time as the upper chamber 121 and the lower chamber 122 become conductive, liquid flows from the lower chamber 122 into the reservoir chamber 114, and a damping force is generated by the bottom valve orifice 118 a of the bottom valve 118 and the compression side damping valve 126.

The double-cylinder strut type shock absorber as in the present embodiment needs to secure sufficient strength in the vicinity of the knuckle mounting portion 104 with respect to lateral force (force in the Z direction). In recent years, automobiles have been required to be lighter in order to improve fuel efficiency in consideration of environmental influences, and it is necessary to ensure both strength and weight reduction. Means for solving this will be described.

The relationship of the plate thickness in the radial direction of the outer cylinder 113 will be described with reference to FIG. First, it passes through the stroke center point 400a, which is the center point of the circular section of the inner cylinder 112 (outer cylinder 113), and is the intermediate point (opposite surface) of the distance between the opposed inner sides of the pair of knuckle attachment parts 104 (

knuckle attachment parts

104a, 104b). The first virtual line 500 is defined as a virtual line passing through the middle of the first virtual line 500. Further, the first imaginary line 500 passes through the knuckle fastening center point 401b which becomes the knuckle fastening center line 401 passing through the centers of all the bolt holes 105 shown in FIG. A virtual line passing through the stroke center point 400a by rotating clockwise from the first virtual line 500 about the stroke center point 400a by 45 ° is defined as a second virtual line 501. A virtual line orthogonal to the second virtual line 501 and passing through the stroke center point 400a is defined as a third virtual line 502.

A line connecting the middle of the opposing surfaces of the pair of

knuckle attachment portions

104a and 104b and the stroke center point 400a serving as the central axis of the outer cylinder 113, that is, the plate of the outer cylinder 113 on the knuckle attachment portion 104 side on the first imaginary line 500 the thickness and _{t a,} when the thickness of the outer tube 113 opposite to the knuckle mounting portion 104 with respect to the stroke center point 400a and the _{t _c,} satisfy the relationship of _t a> t _c. In other words, ta is _a thick portion (first thick portion) with respect to t _c .

Further, in the present embodiment, the virtual area in the vehicle body outside direction partitioned by the second virtual line 501 and the third virtual line 502 is the virtual area I, the virtual area in the vehicle front direction is the virtual area II, and the virtual area in the vehicle rear direction is virtual. The region is defined as a virtual region III, and the virtual region in the vehicle body inner direction is defined as a virtual region IV. t _a is the plate thickness in the virtual region I, and t _c is the plate thickness in the virtual region IV. Then, in the present embodiment, the _{t a} and _{t c} overlying first imaginary line 500, have become 'minimum thickness _{t c} and' minimum thickness _{t a} respective _(t a = _{t a} ', t _c = t _c ').

Also defines the thickness of the outer cylinder 113 in the virtual area II or virtual area III and t _b. In the present embodiment, a fourth imaginary line 503 that passes through the stroke center point 400 a serving as the central axis of the outer cylinder 113 and is orthogonal to the first imaginary line 500 is formed, and the thickness of the outer cylinder 113 on the fourth imaginary line 503 is are you a _{t b.} The fourth imaginary line 503 is at a position rotated from the second imaginary line 501 by 45 ° (θ1 = 45 °) in the clockwise direction. The plate thickness t _b is formed to be thicker than the plate thickness t _c (t _b > t _c ), and the plate thickness t _b is the second thick portion. In the above, the relationship between the plate thicknesses t _a , t _b , and t _c is t _a > t _b > t _c .

In the present embodiment, the thickness of the outer tube 113, as it goes from the position of the plate thickness t _a to the position of the plate thickness t _c, the plate thickness is thin (small). Therefore, the minimum plate thickness t _b ″ of the outer cylinder 113 in the virtual region II or the virtual region III is located in the vicinity of the second virtual line 501 and the third virtual line 502. In this embodiment, so that 'do not coincide with (t _{_b} ≠ t _{_b'} thickness t _b and the minimum thickness t _b of the outer cylinder 113 _'') sets the sheet thickness t _b to match Anyway. In this embodiment, the relationship is t _b ′> t _b ″, and t _b ′ is not the minimum plate thickness. However, for convenience of explanation, t _b ′ is the minimum plate thickness, and the plate thickness t _b Assuming that the minimum plate thickness t _b ′ matches (t _b = t _b ′), the following description will be given.

The minimum plate thickness t _a ′ of the outer cylinder 113 in the virtual area I is thicker than the minimum plate thickness t _b ′ of the outer cylinder 113 in the virtual area II or the virtual area III, and the outer cylinder 113 in the virtual area II or the virtual area III. The minimum plate thickness t _b ′ is thicker than the minimum plate thickness t _c ′ of the outer cylinder 113 in the virtual region IV. That is, the minimum plate thickness in each virtual region has a relationship of t _a ′> t _b ′> t _c ′.

The shock absorber 110 shown in FIG. 2 has a load parallel to the longitudinal direction of the vehicle body (X direction) and the vehicle interior / exterior direction (Z) at the tip of the piston rod 103 due to a change in vehicle body posture due to acceleration / deceleration or turning during vehicle travel. The resultant force of the load parallel to (direction) acts on the rod tip in the Y axis direction as a lateral force. The shock absorber 110 is fastened to the knuckle 302 via the knuckle attachment portion 104a and the knuckle attachment portion 104b, and becomes a fixing portion against the lateral force. To do.

As shown in FIG. 3, the parallel component force F _tz in each component of the lateral force, the vehicle body longitudinal direction (X axis direction) force component F _tx parallel to the vehicle body and out direction (Z axis direction) acting . The reactive force component acting on the knuckle 302 is a component force F _bx parallel to the longitudinal direction of the vehicle body (X-axis direction) and a component force F _bz parallel to the inside / outside direction of the vehicle body (Z-axis direction). When the vehicle travels, the magnitude and direction of the lateral force component change randomly and momentarily on the shock absorber 110 and act on the rod tip in the Y-axis direction on the stroke center point 400a. Bending deformation occurs in the shock absorber 110 by the action of each component force. The knuckle attachment portion 104a in the Y-axis direction in the vicinity of the line AA ′ shown in FIG. 2 and the outer cylinder 113 in the vicinity of the knuckle attachment portion 104b are the roots of bending deformation and generate high stress, so that they can withstand bending deformation. It is necessary to ensure strength.

In particular, the minimum thickness t _a in each virtual region of virtual area I ~ virtual area IV shown in FIG. 3 ', t _b', the outer diameter surface of the outer cylinder 113 as the t c _', high stress respectively sigma _a, Stress σ _b and stress σ _c are generated. A distance l in the Z-axis direction between the stroke center point 400a at which F _tx and F _tz acting as the lateral force components act and the knuckle fastening center point 401b at which F _bX and F _bZ acting as the reaction force components act. _{There is} a deviation of _b . Therefore, a local bending moment M _tz by the lateral force component force F _tz of the vehicle inner and outer directions shown in FIG. 2 in the knuckle mounting portion 104a and the knuckle mounting portion 104b and the outer cylinder 113 in the vicinity of, the longitudinal direction of the vehicle body shown in FIG. 3 A local bending moment M _tx is generated due to the lateral force component force F _tx .

The distance l _a from the knuckle fastening central point 401b of the fixed point to a point where stress sigma _a is generated, shorter than the distance l _b to the point where the stress sigma _b is generated. Distance l _c from the point where the stress sigma _c is generated to the knuckle fastening central point 401b of the fixed point is longer than the distance l _b to the point where the stress sigma _b is generated. Therefore, since the stress σ _a generation point is closer to the knuckle fastening center point 401b serving as the fixed point than the stress σ _b generation point, the stress σ _a is more localized than the stress σ _{b with} respect to the lateral force component F _tx . The bending moment M _tx increases. For generation point of stress sigma _a is closer than the originating point of the stress sigma _c relative to the knuckle fastening central point 401b of the fixed point, the stress relative to the lateral force F _tz sigma _a stress sigma _c from the local bending moment M _{Increased by tz} .

Further, the lateral force in the longitudinal direction of the vehicle body that is generally applied by acceleration / deceleration during traveling of the vehicle is greater than the lateral force that is applied in the vehicle interior / exterior direction due to a change in the posture of the vehicle body due to steering. Therefore, the stress σ _b becomes larger than the stress σ _c . Since the shock absorber 110 is configured as described above, the minimum thickness t _a ′ of the outer cylinder 113 in the virtual area I is the minimum thickness t _b of the outer cylinder 113 in the virtual area II or the virtual area III. 'Thicker, the minimum plate thickness t _b ' of the outer cylinder 113 in the virtual region II or the virtual region III is thicker than the minimum plate thickness t _c 'of the outer tube 113 in the virtual region IV, and thick only in places where strength is required. As a result, the static strength and fatigue strength can be satisfied for each of the stress σ _a , the stress σ _b , and the stress σ _c , and the weight can be reduced while suppressing an increase in diameter.

Although the _'minimum thickness t _b of the virtual area _III' minimum thickness t _b of the virtual area II of the same in this embodiment, may be configured to plate thickness is different. Further, in the outer cylinder 113, it is preferable that the inner diameter is the same in the circumferential direction and that the wall thickness is increased in the outer diameter direction because the section modulus increases. In the present embodiment, the inner diameter direction may be increased, or the inner diameter direction and the outer diameter direction may be increased simultaneously.

The minimum plate thickness relationship of the outer cylinder 113 described above is established by a cross-section AA ′ of an arbitrary outer cylinder 113 at least at one place on the + Y axis direction side from the bolt hole 105 (105a, 105b) shown in FIG. It ’s fine. It is preferable that the position closer to the bolt hole 105 (105a, 105b), which is the base of deformation with respect to the lateral force, has the minimum plate thickness relationship of the outer cylinder 113 described above. Specifically, the thick portion is at least + Y-axis direction (hole 113a side) from the + Y-axis side of the bolt hole 105 (105a, 105b), and from the −Y-axis side end portion of the stabilizer bracket 119 to the −Y-axis direction. It is preferable to establish in the range (bottom side). For the shock absorber 110 for a vehicle type that does not have the stabilizer bracket 119, the thick portion is at least + Y-axis direction from the + Y-axis side of the bolt hole 105 (105a, 105b), and -Y from the −Y-axis side end portion of the spring seat 120. It is preferable to establish it in the axial range. The thick portion is preferably provided from the root of the end portion on the hole 113a side of the knuckle attachment portion 104 to the bolt hole 105 (105a, 105b).

In this embodiment, the outer cylinder 113 has a uniform cross-sectional shape in the Y-axis direction. However, the effect of the present embodiment can also be realized as an uneven shape that is thinned continuously or stepwise while establishing the minimum thickness relationship from the + Y-axis side of the bolt hole 105 (105a, 105b) to the tip of the outer cylinder. Can be obtained. The thick portion may be formed at least in the + Y-axis direction from the + Y-axis side of the bolt hole 105 (105a, 105b) and from the -Y-axis side end of the stabilizer bracket 119 to the -Y-axis direction. . With respect to the shock absorber 110 for a vehicle type that does not have the stabilizer bracket 119, at least the range of the bolt hole 105 (105a, 105b) in the + Y-axis direction from the + Y-axis side and the −Y-axis direction from the −Y-axis side end of the spring seat 120 The shape may be such that the thick part is formed.

In this embodiment, an aluminum alloy material is applied as the constituent material of the outer cylinder 113. Instead of the aluminum alloy material, the constituent material may be a steel material, a magnesium alloy material, a titanium alloy material, a resin material, a carbon-based composite material, or a glass-based composite material. However, the inner cylinder 112, the outer cylinder 113, the stabilizer bracket 119, and the spring seat 120 are used in order to make the linear expansion coefficient equal to the thermal deformation caused by the change in the environmental temperature and the heat generation of the liquid at the time of the stroke. The knuckle attachment portion 104a and the knuckle attachment portion 104b are preferably made of the same material. In this embodiment, the inner cylinder 112, the outer cylinder 113, the stabilizer bracket 119, the spring seat 120, the knuckle attachment portion 104a and the knuckle attachment portion 104b may be made of different materials. Further, the inner cylinder 112, the outer cylinder 113, the stabilizer bracket 119, the spring seat 120, the knuckle attachment portion 104a and the knuckle attachment portion 104b are subjected to surface treatment or heat treatment such as plating or anodized for the purpose of rust prevention or surface hardness improvement. You may do it.

As a manufacturing method of the outer cylinder 113, it is preferable to use gravity casting production as a method of forming a circumferentially uneven thickness shape. As another manufacturing method, die casting, cutting, forging, extrusion, or molding by drawing may be used. In the present embodiment, the outer cylinder 113 is formed by integrally casting the stabilizer bracket 119, the knuckle attachment portion 104a, and the knuckle attachment portion 104b, thereby improving the product strength and reducing the number of parts by reducing the number of joints. In this embodiment, the spring seat 120 is press-fitted and fixed. However, the spring seat 120 may be molded by integral casting, welded or bonded as a separate part, or molded to the outer cylinder 113 by injection molding or the like. Alternatively, the stabilizer bracket 119 may be molded as a separate part by welding, bonding, injection molding or the like on the outer cylinder 113. The knuckle attachment portion 104a and the knuckle attachment portion 104b may also be molded as separate parts by welding, bonding, injection molding or the like on the outer cylinder 113.

The shock absorber 110 of the present embodiment is not limited to the above-described one. For example, a type of switching a damping performance by switching a plurality of pistons with an actuator with respect to a road surface input frequency or a type of switching a damping performance with external energy. It may be a control double cylinder type strut type shock absorber. Further, the shock absorber 110 of this embodiment may be a multi-cylinder strut type shock absorber using air, a magnetic viscous fluid, an electroviscous fluid, or the like as a medium for exerting a damping force. Further, it may be a single cylinder strut type shock absorber or an inverted single cylinder type or double cylinder type strut type shock absorber that fastens a piston rod to the knuckle side.
(Effect of this embodiment)
In the present embodiment, a shock absorber having a piston 111 and a buffer mechanism having a piston rod 103 coupled to the piston 111, and a cylindrical casing (outer cylinder 113) that houses the buffer mechanism, The (outer cylinder 113) is provided integrally with the casing (outer cylinder 113), and has a pair of

knuckle attachment portions

104a and 104b protruding in one direction from the outer surface of the casing (outer cylinder 113). The

knuckle mounting portions

104a and 104b of the

knuckle mounting portions

104a and 104b face the wide surfaces, respectively, and the wide surfaces are provided along the axial direction of the casing (outer cylinder 113). The casing (outer cylinder 113) is attached to a pair of knuckles. The thickness of the casing (outer cylinder 113) on the

knuckle mounting part

104a, 104b side on the imaginary line connecting the middle of the opposing surfaces of the

sections

104a and 104b and the central axis of the casing (outer cylinder 113) is ta. When the thickness of the casing (outer cylinder 113) on the opposite side of the

knuckle attachment portions

104a and 104b with respect to the central axis of the body (outer cylinder 113) is tc, a thick portion that satisfies the relationship ta> tc Try to form.

According to the present embodiment, it is possible to provide a shock absorber capable of ensuring strength and reducing the weight.

In addition to the above, in this embodiment, the casing (outer cylinder 113) has a bottom surface facing the piston 111 and a hole 113a from which the piston rod 103 protrudes, and each of the pair of

knuckle mounting portions

104a and 104b. Are provided with

bolt holes

105a and 105b at opposite positions, and the thick portion is provided closer to the hole 113a than the

bolt holes

105a and 105b in the axial direction of the housing (outer cylinder 113).

According to the present embodiment, since the thick portion is formed at a location where strength is required, the thickness of the housing (outer cylinder 113) is not increased more than necessary, and the weight can be reduced. Can do.

In addition to the above, in this embodiment, the housing (outer cylinder 113) has a stabilizer bracket 119 closer to the hole 113a than the

knuckle attachment portions

104a and 104b, and the thicker portion is more than the stabilizer bracket 119. Provided on the bottom side.

Further, in addition to the above, in the present embodiment, the thick portion is provided from the end side base at the hole 113a side of the

knuckle mounting portions

104a and 104b to the

bolt holes

105a and 105b.

In addition to the above, in this embodiment, the thickness of the casing (outer cylinder 113) on another virtual line (fourth virtual line 503) orthogonal to the virtual line (first virtual line 500) is set to tb. The body (outer cylinder 113) forms a second thick part where the thickness tb of the casing (outer cylinder 113) satisfies tb> tc.

Further, in addition to the above, in this embodiment, the casing (outer cylinder 113) has a relationship of ta> tb> tc.

According to the present embodiment, since the thick portion is formed at a place where strength is required, the thickness of the housing (outer cylinder 113) is not increased more than necessary, and the weight can be reduced. Can do.

Further, in this embodiment, the piston 111, the piston rod 103 connected to the piston 111, the cylindrical inner cylinder 112 that accommodates the piston 111 and the piston rod 103, the outer cylinder 113 that accommodates the inner cylinder 112, The outer cylinder 113 is provided integrally with the outer cylinder 113, and has a pair of

knuckle attachment portions

104a and 104b projecting in one direction from the outer surface of the outer cylinder 113, and the pair of knuckle attachments Each of the

portions

104a and 104b has a wide surface facing each other, and the wide surface is provided along the axial direction of the outer cylinder 113. The outer cylinder 113 is connected to the intermediate point between the opposing surface of the pair of

knuckle mounting portions

104a and 104b. A line passing through the cross-sectional center point of the cylinder 112 is defined as a first imaginary line 500, and the first imaginary line 500 is defined as 4 centering on the cross-sectional center point of the inner cylinder 112. A line passing through the center of the cross section of the inner cylinder 112 rotated clockwise is a second imaginary line 501, a third imaginary line 502 orthogonal to the second imaginary line 501 and passing through the center of the cross section of the inner cylinder 112, The vehicle body outer side direction partitioned by the second virtual line 501 and the third virtual line 502 is defined as a virtual region I, and the vehicle body front direction partitioned by the second virtual line 501 and the third virtual line 502 is defined as a virtual region II. The rear direction of the vehicle body partitioned by the virtual line 501 and the third virtual line 502 is defined as a virtual region III, and the vehicle interior direction partitioned by the second virtual line 501 and the third virtual line 502 is defined as a virtual region IV. When the minimum plate thickness of the inner cylinder 113 is ta ′ and the minimum plate thickness of the outer cylinder 113 in the virtual region IV is tc ′, the outer cylinder 113 is a thick portion that satisfies the relationship ta ′> tc ′. To form.

In addition to the above, the outer cylinder 113 has a bottom surface to which the piston 111 faces and a hole 113a from which the piston rod 103 projects, and each of the pair of

knuckle mounting portions

104a and 104b is opposed to the above.

Bolt holes

105a and 105b are provided at the locations where the thickening portions are provided, and the thick portion is provided closer to the holes 113a than the

bolt holes

105a and 105b in the axial direction of the outer cylinder 113.

In addition to the above, in this embodiment, the outer cylinder 113 has a stabilizer bracket 119 closer to the hole 113a than the

knuckle attachment portions

104a and 104b, and the thick portion is provided on the bottom side of the stabilizer bracket 119. Yes.

Further, in addition to the above, in the present embodiment, the thick portion is provided from the root side end on the hole 113a side of the

knuckle attachment portions

104a and 104b to the

bolt holes

105a and 105b.

Further, in addition to the above, in the present embodiment, the outer cylinder 113 is a second that satisfies t _b ′> t _c ′ when the minimum plate thickness of the outer cylinder 113 in the virtual region II or the virtual region III is t _b ′. It has a thick part.

In addition to the above, in the present embodiment, the outer cylinder 113 has a relationship of t _a ′> t _b ′> t _c ′.

In addition, according to the present embodiment, the minimum plate thicknesses t _a ′, t _b ′, and t _c ′ are obtained in the virtual areas I to IV by the F _tX and F _tZ that are the lateral force _components. While ensuring the strength against the high stress σa, stress σb, and stress σc generated on the outer diameter surface of the outer cylinder 113, it is possible to suppress the size increase and reduce the weight.

The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of the embodiment.

The present invention is suitable for a strut type shock absorber that receives a lateral load, but may be a shock absorber used for other types of suspensions.

DESCRIPTION OF SYMBOLS 100 ... Suspension apparatus, 102 ... Cylinder, 103 ... Piston rod, 104 ... Knuckle attaching part, 104a ... Knuckle attaching part, 104b ... Knuckle attaching part, 105 ... Bolt hole, 105 ... Bolt hole, 105b ... Bolt hole, 105c ... Bolt Hole, 105d ... Bolt hole, 110 ... Shock absorber, 111 ... Piston, 112 ... Inner cylinder, 113 ... Outer cylinder, 113a ... Hole, 119 ... Stabilizer bracket, 200 ... Car body, 300 ... Wheel, 302 ... Knuckle, 400 ... Center 401, knuckle fastening center line, 500 ... first imaginary line, 501 ... second imaginary line, 502 ... third imaginary line, 503 ... imaginary line

Claims

A buffer mechanism having a piston and a piston rod coupled to the piston;
In a shock absorber having a cylindrical housing that houses the buffer mechanism,
The housing is provided integrally with the housing, and has a pair of knuckle attachment portions protruding in one direction from the outer surface of the housing,
The pair of knuckle attachment portions are opposed to the wide surfaces, and the wide surfaces are provided along the axial direction of the housing.
The housing is
The thickness of the knuckle mounting portion of the housing on the virtual line connecting the center axis of the housing and the facing surface intermediate of said pair of knuckle mounting portion and t a,
It has a thick portion that satisfies a relationship of t a > t c , where t c is the thickness of the case on the opposite side of the knuckle mounting portion with respect to the central axis of the case. shock absorber.
In claim 1,
The housing has a bottom surface facing the piston, and a hole from which the piston rod protrudes,
Each of the pair of knuckle attachment portions is provided with a bolt hole at an opposite location,
The shock absorber according to claim 1, wherein the thick portion is provided closer to the hole than the bolt hole in the axial direction of the housing.
In claim 2,
The housing has a stabilizer bracket on the hole side from the knuckle attachment portion,
The shock absorber according to claim 1, wherein the thick portion is provided closer to the bottom surface than the stabilizer bracket.
In claim 3,
The shock absorber according to claim 1, wherein the thick portion is provided from an end portion side base of the knuckle attachment portion to the bolt hole.
In claim 4,
The thickness of the casing on another virtual line orthogonal to the virtual line is t b ,
The shock absorber according to claim 1, wherein the housing has a second thick portion where a thickness t b of the housing satisfies t b > t c .
In claim 5,
The shock absorber according to claim 1, wherein the casing satisfies t a > t b > t c .
A piston and a piston rod coupled to the piston;
In a shock absorber having a cylindrical inner cylinder that accommodates the piston and the piston rod, and an outer cylinder that accommodates the inner cylinder,
The outer cylinder is provided integrally with the outer cylinder, and has a pair of knuckle attachment portions protruding in one direction from the outer surface of the outer cylinder,
The pair of knuckle attachment portions are opposed to the wide surfaces, and the wide surfaces are provided along the axial direction of the outer cylinder,
A line passing through the opposing surface midpoint of the pair of knuckle attachment portions and the cross-sectional center point of the inner cylinder is a first imaginary line
The first imaginary line is a line passing through the cross-sectional center point of the inner cylinder rotated 45 ° clockwise around the cross-sectional center point of the inner cylinder as a second imaginary line,
A third imaginary line orthogonal to the second imaginary line and passing through the cross-sectional center point of the inner cylinder,
A vehicle body outside direction partitioned by the second imaginary line and the third imaginary line is a virtual area I,
The vehicle front side direction partitioned by the second imaginary line and the third imaginary line is defined as a virtual area II,
The vehicle body rear side direction partitioned by the second imaginary line and the third imaginary line is a virtual region III,
A vehicle body inner side direction divided by the second imaginary line and the third imaginary line is defined as a virtual area IV,
When the minimum plate thickness of the outer cylinder in the virtual region I is t a ′, and the minimum plate thickness of the outer cylinder in the virtual region IV is t c ′,
The shock absorber according to claim 1, wherein the outer cylinder has a thick portion that satisfies a relationship of t a '> t c '.
In claim 7,
The outer cylinder has a bottom surface facing the piston, and a hole from which the piston rod protrudes,
Each of the pair of knuckle attachment portions is provided with a bolt hole at an opposite location,
The shock absorber according to claim 1, wherein the thick portion is provided closer to the hole than the bolt hole in the axial direction of the outer cylinder.
In claim 8,
The outer cylinder has a stabilizer bracket on the hole side from the knuckle attachment portion,
The shock absorber according to claim 1, wherein the thick portion is provided closer to the bottom surface than the stabilizer bracket.
In claim 9,
The shock absorber according to claim 1, wherein the thick portion is provided from an end portion side base of the knuckle attachment portion to the bolt hole.
In claim 10,
The outer cylinder has a second thick portion where t b ′> t c ′, where t b ′ is the minimum plate thickness of the outer cylinder 113 in the virtual area II or the virtual area III. A characteristic shock absorber.
In claim 11,
The outer cylinder is a shock absorber, characterized in that a t a '> t b'> t c '.