JP2018123858A - Ball joint and bearing sheet thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball sheet capable of securing load bearing and also effectively holding lubricant, and a ball joint including the ball sheet.SOLUTION: A ball joint is provided with a pressure receiving part 32 contacting with a ball part 28 in a slidable manner with compressive load in an axial direction of a ball stud received from the ball part 28. The pressure receiving part 32 includes a pressure receiving part body 41 whose outer periphery 41a and inner periphery 41b are formed into a spherical shape and have a substantially constant thickness. The pressure receiving part 32 includes a plurality of spherical projections 42 provided on the inner periphery of the pressure receiving part body 41 at a predetermined interval so as to contact with the ball part 28. A numerical value obtained by dividing the sum of a root radius as a radius at a position where the projection 42 contacts with the pressure receiving part body 41 and the interval by the root radius is set larger than 1.1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a ball joint bearing seat for holding a ball portion of a ball stud and a ball joint including the same.

  Conventionally, for example, a ball joint used for a suspension device of a vehicle such as an automobile or a steering device is made of a ball stud having a ball portion and a stud portion integrally and a synthetic resin that rotatably holds the ball portion of the ball stud. And a cylindrical ball sheet that is a bearing sheet, and a bottomed cylindrical housing that receives the ball sheet holding the ball portion. Between the outer peripheral surface of the ball portion and the inner peripheral surface of the ball seat, a fluid grease as a lubricant is interposed to ensure good slidability when the ball portion is rotated. For example, in the ball seat, a rib is provided on the outer periphery of the pressure receiving portion that receives the input load, and a protrusion having a flat tip is provided on the inner periphery, and the contact area between the surface of the ball portion and the inner peripheral surface of the seat is controlled to form a gap. A configuration in which the lubricity due to the interposed grease is improved and the lubricity is improved is known (for example, see Patent Document 1).

Japanese Patent No. 5355280 (page 4-9, FIGS. 1 to 4)

  In the case of a ball joint, the required torque is generated by the sliding of the outer peripheral surface of the ball portion and the inner peripheral surface of the ball seat, but with the sliding, the grease located between the ball portion and the ball seat is generated. It is scraped and no longer exists between the ball part and the ball sheet. That is, the ball portion and the ball sheet come into direct contact with the sliding. In such a case, the boundary lubrication state occurs, which is a factor that promotes the progress of wear of the ball seat.

  In order to prevent such wear from being promoted, a grease retaining portion is provided at the bottom of the ball seat, or a grease pocket or the like to secure the amount of grease retained for the entire contact area between the ball portion and the ball seat. It is conceivable to provide a groove. However, if these grease retaining structures are provided on the sliding surface to which the load from the ball stud side is applied most, the contact area between the ball portion and the ball seat will decrease, resulting in a high load locally. It is not preferable to give the structure to the sliding surface. That is, there is a demand for a configuration that can appropriately retain the lubricant while maintaining resistance to high loads.

  And such a subject is the same also about the ball joint used not only for the ball joint for vehicles but in arbitrary places.

  The present invention has been made in view of such points, and an object of the present invention is to provide a ball joint bearing seat capable of effectively holding a lubricant while ensuring load resistance and a ball joint including the same. To do.

  The ball joint bearing seat according to claim 1, wherein the ball joint bearing seat is housed in a housing and holds a ball portion of the ball stud via a lubricant. The ball seat has an axial direction from the ball portion to the ball stud. A pressure receiving portion that comes into contact with the ball portion in a slidable state while receiving a compressive load, and an opening at which a part of the ball stud is led out to the outside is provided at one end side of the pressure receiving portion. A pressure receiving portion main body having a substantially constant thickness whose outer periphery and inner periphery are each formed in a spherical shape, and protruding from the inner periphery of the pressure receiving portion main body. A plurality of spherical protrusions arranged in contact with each other and spaced apart at a predetermined interval, and a numerical value obtained by dividing the sum of the radius of the protrusion at a position in contact with the pressure receiving body and the interval by the radius is 1. It is greater than 1.

  According to a second aspect of the present invention, there is provided a ball joint comprising: a housing; the bearing seat according to the first aspect; the lubricant disposed in the bearing seat; and a ball portion held by the bearing seat. And a ball stud provided.

  A ball joint according to a third aspect is the ball joint according to the second aspect, wherein the protrusion has a protrusion height of 0.02 mm or more when deformed by contact with the ball portion.

The ball joint according to claim 4 is the ball joint according to claim 2 or 3, wherein the lubricant per protrusion is 0.01 mm ³ or more.

  According to the ball joint bearing sheet according to claim 1, the pressure receiving body of the pressure receiving portion that receives the compressive load in the axial direction of the ball stud has a substantially constant thickness with the outer circumference and the inner circumference each being spherical. By controlling the gap formed between the ball part and controlling the pressure receiving load and the lubrication state by making the plurality of protrusions protruding from the pressure receiving part main body spherical, Deterioration due to repeated input of compressive load can be suppressed, and the value obtained by dividing the sum of the radius and the interval at the position where the protrusion is in contact with the pressure receiving body main body by the radius is larger than 1.1, so that The amount of the lubricant retained can be secured, and the lubricant can be effectively retained.

  According to the ball joint of the second aspect, by providing the bearing seat of the first aspect, it is possible to provide a ball joint having excellent durability against repeated compression load and sliding friction between the ball portion and the bearing sheet.

  According to the ball joint of the third aspect, in addition to the effect of the ball joint according to the second aspect, the protrusion height in a state where the protrusion is deformed by contact with the ball portion is set to 0.02 mm or more. As a result, it is possible to more reliably achieve both a reduction in the input load per protrusion and a securing amount of lubricant.

According to the ball joint of the fourth aspect, in addition to the effect of the ball joint of the second or third aspect, the lubricant per protrusion is 0.01 mm ³ or more so that the input load per protrusion is increased. It is possible to achieve both a reduction in the amount of lubricant and the amount of lubricant retained more reliably.

It is sectional drawing which shows the bearing seat of the ball joint of one embodiment of this invention. It is sectional drawing which shows the ball joint provided with the bearing seat same as the above. It is sectional drawing which expands and schematically shows a part of bearing seat same as the above. It is explanatory drawing for calculating the volume of the state deform | transformed by the contact with the ball | bowl part of the protrusion of a bearing seat same as the above. It is explanatory drawing for calculating the retention amount of the lubricant per protrusion of a bearing seat same as the above.

  The configuration of an embodiment of the present invention will be described below with reference to the drawings.

  In FIG. 2, reference numeral 11 denotes a ball joint. The ball joint 11 is used for a suspension device of a vehicle such as an automobile or a steering device. The ball joint 11 includes a socket 16 that is a housing (receiving side member), a ball stud 17 that is a ball side member, and a part of the ball stud 17 that is slidably (rotatably) held in the socket 16 A substantially cylindrical ball sheet 18 that is a bearing seat accommodated in the housing, and a dust cover 19 disposed from the outer peripheral surface of the socket 16 to the outer peripheral surface of the ball stud 17, with the socket 16 being disposed on the upper side. It is of the compression type. In the following description, the lower side in FIGS. 1 and 2 is described as a lower side that is one end side, and the upper side is an upper side that is the other end side.

  The socket 16 is made of metal formed into a bottomed cylindrical shape (covered cylindrical shape) by, for example, (cold) forging or casting. The socket 16 is integrally provided with a cylindrical main body portion 21 and a reduced diameter portion 22 continuous with the upper end portion of the main body portion 21. In addition, the socket 16 has an inner chamber 23 that is a housing portion for housing the ball seat 18 inside, and a socket opening 24 that communicates the inner chamber 23 and the outside of the socket 16 at the lower end. Is formed. Further, a cover attachment portion 25 for attaching and fixing the upper end portion of the dust cover 19 is formed on the outer periphery of the socket 16.

  The reduced diameter portion 22 is formed so as to be gradually reduced in diameter from the lower end side which is the main body portion 21 side to the upper end side.

  The inner chamber 23 is formed in a spherical shape that gradually decreases in diameter from the lower end side to the upper end side over the main body portion 21 or the reduced diameter portion 22.

  An annular plug 26 as a holding member for preventing the ball seat 18 accommodated in the inner chamber 23 from being detached is attached to the socket opening 24 by, for example, caulking and fixing.

  On the other hand, the ball stud 17 is made of, for example, steel, and integrally includes a spherical ball portion 28 and a shaft-shaped stud portion 29 connected to the ball portion 28.

  A part of the outer peripheral surface 28 a of the ball portion 28 is held on the ball seat 18 so as to be slidable (rotatable) via a lubricant (grease) G. That is, the ball portion 28 is accommodated in the inner chamber 23 of the socket 16 together with the ball seat 18.

  The stud portion 29 is a portion to which a load is applied by being connected to an external connected member (not shown), and protrudes outward (downward in FIG. 2) from the socket 16.

  The ball seat 18 shown in FIGS. 1 and 2 is formed in a substantially cylindrical shape made of, for example, a synthetic resin having excellent wear resistance, and is fitted and held in the inner chamber 23 of the socket 16. The ball seat 18 is integrally provided with a body portion 31 that is a cylindrical seat body portion and a pressure receiving portion 32 that is continuous with the upper end of the body portion 31. The outer periphery of the ball seat 18 is provided with an air release groove for releasing the air when the ball seat 18 is assembled to the inner chamber 23 of the socket 16 at at least one of the body portion 31 and the pressure receiving portion 32. May be.

  The body portion 31 is located on the lower end side of the pressure receiving portion 32 and is a portion located inside the main body portion 21 of the socket 16 in a state where the ball seat 18 is fitted in the inner chamber 23. An opening 34 is provided at the lower end of the body 31. Further, an inner peripheral side protruding portion 36 that protrudes inward and an outer peripheral side protruding portion 37 that protrudes outward are formed at the lower end portion of the body portion 31. Further, the lower end portion of the body portion 31 is in contact with a plug 26 attached to the socket 16 in a state where the ball seat 18 is accommodated in the inner chamber 23 of the socket 16.

  The opening 34 communicates with the socket opening 24 of the socket 16 in a state where the ball seat 18 is fitted in the inner chamber 23, and leads the stud portion 29 side of the ball stud 17 to the outside of the socket 16.

  The inner peripheral protrusion 36 constitutes an edge of the opening 34. This inner peripheral side protruding portion 36 gradually moves from the position corresponding to the equator position E (the maximum diameter position of the ball portion 28 in the axial direction of the ball stud 17) of the inner peripheral ball portion 28 of the body portion 31 to the lower end side. Are curved so as to protrude toward the center axis (inward). Further, the inner peripheral side protruding portion 36 is slightly outward with respect to the outer peripheral shape of the ball portion 28 when the ball seat 18 is in a single state, that is, when the ball seat 18 is not accommodated in the inner chamber 23 of the socket 16. The shape is separated.

  The outer peripheral side protruding portion 37 is located on the outer periphery of the lower end portion of the body portion 31 (ball seat 18), that is, on the back side of the inner peripheral side protruding portion 36. This outer peripheral side protruding portion 37 is formed to be curved so as to gradually protrude in the radial direction (outward) from the lower side to the lower end side from the equator position E of the ball portion 28 on the outer periphery of the body portion 31. Yes. Further, the outer peripheral side protruding portion 37 protrudes slightly outward with respect to the shape of the inner chamber 23 when the ball sheet 18 is in a single state, that is, when the ball sheet 18 is not accommodated in the inner chamber 23 of the socket 16. It has a shape.

  Then, the outer peripheral side protruding portion 37 is deformed so as to be pushed toward the central axis side (inward) along the inner surface of the inner chamber 23 in a state where the ball seat 18 is accommodated and held in the inner chamber 23 of the socket 16. Thus, the inner peripheral side protruding portion 36 is curved so as to follow the outer peripheral shape of the ball portion 28, and is configured to be elastically compressed and liquid tightly adhered to the outer peripheral surface 28a of the ball portion 28. .

  Therefore, the lower end portion of the body portion 31 of the ball seat 18 is a semi-molded type in which the ball seat 18 is slightly deformed by being assembled to the inner chamber 23 of the socket 16 and is in close contact with the outer peripheral surface 28a of the ball portion 28. Yes. Here, the semi-molded type means that the inner peripheral side (inner peripheral side protruding portion 36) of the lower end portion of the body portion 31 is curved and protruded into a spherical shape in close contact with the outer peripheral surface 28a of the ball portion 28, and the lower end portion. The so-called molding type that does not substantially project the outer peripheral side of the ball, and the ball seat 18 is assembled to the inner chamber 23 of the socket 16 by projecting the outer peripheral side largely without forming a protruding part on the inner peripheral side of the lower end of the body part 31 in advance. By caulking and deforming the socket 16, the lower end portion of the body portion 31 together with the socket 16 is largely deformed, which means an intermediate level between the so-called deformation type in which the socket 16 is in close contact with the outer peripheral surface 28a of the ball portion 28. That is, the lower end portion of the semi-molded body portion 31 of the ball seat 18 has a smaller amount of protrusion to the inner peripheral side than the molded type (protrusion amount of the inner peripheral protrusion 36), and to the outer peripheral side than the deformation type. The amount of protrusion (the amount of protrusion of the outer peripheral protrusion 37) is small.

  Further, the pressure receiving portion 32 is located inside the reduced diameter portion 22 of the socket 16 in a state where the ball seat 18 is fitted in the inner chamber 23, and extends in the axial direction (upward direction) of the ball stud 17 from the ball portion 28. It is a portion that contacts the ball portion 28 in a slidable state while receiving a compressive load. The pressure receiving portion 32 is integrally provided with a pressure receiving portion main body 41 and a plurality of protrusions 42 protruding from the inner periphery of the pressure receiving portion main body 41. Further, the pressure receiving portion 32 is provided with an end opening 43 at the upper end, that is, the end opposite to the body portion 31.

  The pressure receiving portion main body 41 is formed in a substantially spherical shape with an outer periphery 41a facing (in close contact) with the inner chamber 23 of the socket 16 and an inner periphery 41b facing the ball portion 28, and is substantially thin. The thickness is constant. In other words, the pressure receiving portion main body 41 has a shape with substantially no thickness distribution (bias).

  A plurality of the protrusions 42 are arranged at predetermined intervals d in the meridian direction and the latitude direction of the inner periphery 41b of the pressure receiving part main body 41 (FIG. 3), and are provided on substantially the entire upper surface of the inner periphery 41b of the pressure receiving part main body 41. positioned. Each of the protrusions 42 is formed in a spherical shape, and the tip side constitutes a sliding contact portion (true sliding contact surface) 42a in sliding contact with the outer peripheral surface 28a of the ball portion 28. Specifically, the protrusions 42 are deformed by a predetermined amount (deformation amount δ) by the contact with the outer peripheral surface of the ball portion 28 and are crushed to a protruding height H with respect to the inner periphery 41b. The portion 42a is in sliding contact with the outer peripheral surface 28a of the ball portion 28. For this reason, the lubricant G is not interposed between each projection 42 (sliding contact portion 42a) and the outer peripheral surface 28a of the ball portion 28, and the outer periphery of each projection 42 (sliding contact portion 42a) and the ball portion 28. The surface G is in direct contact with the surface 28 a, and the lubricant G scraped by the ball portion 28 is between the protrusions 42 and between the inner periphery 41 b of the pressure receiving body 41 and the outer peripheral surface 28 a of the ball portion 28. Is retained. That is, the lubricant G exists around the protrusion 42. Further, the protrusions 42 have shallow protrusion shapes in which the maximum protrusion dimension from the inner periphery 41b of the pressure receiving body 41 is smaller than the curvature radius R. Therefore, the base radius r, which is the radius of the base portion of each protrusion 42 that contacts the pressure receiving body 41, is set to be smaller than the curvature radius R (R> r).

  The end opening 43 is provided so as to penetrate the pressure receiving body 41 in the thickness direction. The end opening 43 is formed with a smaller diameter than the opening 34. The end opening 43 is a lubricant reservoir for storing the lubricant G.

  Further, the dust cover 19 is also called a dust seal or a boot, and covers the socket opening 24 of the socket 16 regardless of the swinging of the ball stud 17, so that moisture and dust inside the socket 16 or the ball seat 18 are covered. It prevents intrusion. The dust cover 19 is formed in a substantially cylindrical shape with, for example, a synthetic resin, the lower end side is fixed to the outer peripheral surface of the stud portion 29 of the ball stud 17, and the upper end side is fitted to the cover mounting portion 25 of the socket 16. It is fastened and fixed by a ring-shaped fixing member 45 attached to the outer peripheral surface.

  Next, the design of the protrusion 42 of the ball seat 18 will be described.

  The ball joint 11 increases or decreases the load input when the vehicle travels, for example, when riding on an installation such as a curb or when stationary, but even when the maximum load is input, it is converted to 20 [N] or less per projection 42 Occurrence of defects can be suppressed by suppressing to the above. Therefore, although it is desirable to arrange as many protrusions 42 as possible, the more protrusions 42 are disposed, the more space for holding the lubricant G is lost. That is, the number of protrusions 42 and the amount of lubricant G retained are in a trade-off relationship.

  Therefore, in order to achieve both the reduction of the maximum input load per protrusion 42 and the securing of the retained amount of the lubricant G, the inventor according to the present invention is based on the pin-on-disk type reciprocating sliding friction test. As a result of examining the protrusion height H, the size (base radius r), the distance d between the protrusions 42 and 42 as parameters, the numerical value obtained by dividing the sum of the root radius r and the distance d of the protrusion 42 by the root radius r is 1. It was found that an appropriate input load range per protrusion 42 and an appropriate holding amount of the lubricant G are maintained when the ratio is larger than 1, that is, when the following expression (1) is satisfied.

<Formula (1)>
d + r / r> 1.1

  As shown in FIG. 5, the holding amount Vg of the lubricant G per protrusion 42 is such that the length of one side is a square having a distance P (= 2 · r + d) between the centers of the protrusions 42 and 42 and the height is the protruding height. A volume Vp of the projection 42 after deformation is subtracted from a volume V of the rectangular parallelepiped 49 having a height H (Vg = V−Vp). Here, although the bottom surface and the top surface of the rectangular parallelepiped 49 are strictly spherical, the curvature radius of the ball portion 28 and the inner periphery 41b of the pressure receiving portion main body 41 are compared with the curvature radius R and the root radius r of each protrusion 42. Since the curvature radius of is sufficiently large, it can be treated as a substantially flat surface (the curvature radius is infinite).

の関係を満たす。ここで、１／Ｅ^*2＝(１−γ₁ ²)／Ｅ₁＋(１−γ₂ ²)／Ｅ₂である。この式(2)を変形すると、
＜式(3)＞

が求められる。 First, the volume Vp of the protrusion 42 is calculated. As described above, when the curvature radius of the ball part 28 is infinite, the elastic contact between the ball part 28 and the protrusion 42 is based on Hertz's elastic contact theory. From the Young's modulus E ₁ and Poisson's ratio γ _{1 of} 28 material, and the Young's modulus E ₂ and Poisson's ratio γ _{2 of} the ball seat 18 material,
<Formula (2)>

Satisfy the relationship. Here, 1 / E ^{* 2} = (1−γ ₁ ² ) / E ₁ + (1−γ ₂ ² ) / E ₂ . When this equation (2) is transformed,
<Formula (3)>

Is required.

である。 Next, the volume Vp of the projection 42 after deformation can be obtained from the obtained deformation amount δ, the curvature radius R and the root radius r of the projection 42. That is, as shown in FIG. 4, the volume of the projection 42 after the volume obtained by rotating the hatched portion of the circle (x ² + y ² = R ² ) with the radius R expressed on the xy plane around the y-axis is deformed. Volume Vp. That is, as a = √ (R ² −r ² ) and b = R−δ,
<Formula (4)>

It is.

である。 On the other hand, the volume V of the rectangular parallelepiped 49 shown in FIG.
<Formula (5)>

It is.

で求められる。 Therefore, the retention amount Vg of the lubricant G per protrusion 42 is
<Formula (6)>

Is required.

That is, as can be seen from this equation (6), the holding amount Vg of the lubricant G is the deformation amount δ of the protrusion 42, in other words, the protrusion height H after the protrusion 42 is deformed, and the size of the protrusion 42, that is, The radius of curvature R and the root radius r, and the distance d between the protrusions 42, that is, the distance (pitch) P between the centers of the protrusions 42 and 42 are set as parameters. In order to maintain lubrication, the inventor according to the present invention has a protrusion height H after deformation of the protrusion 42 of 20 [μm] or more and / or a holding amount of the lubricant G of 0.01 [mm ³ ] or more. I found out that it was necessary.

For example, when steel is used as the material of the ball portion 28 and polyacetal (POM) is used as the material of the ball seat 18, the Young's modulus E ₁ of the ball portion 28 is 200000 [N / mm ³ ] and the Poisson's ratio γ ₁ is 0. .35, 2856 [N / mm ³ ] as the Young's modulus E ₂ of the ball seat 18, 0.35 as the Poisson's ratio γ ₂ , and 20 [N] as the maximum load F are substituted into the equation (3). As a result, the deformation amount δ = 0.022... 0.02 [mm] of the protrusion 42, and the protrusion height H after deformation of the protrusion 42 is obtained as 0.077. Therefore, it can be seen that under these material conditions, the protrusion height H of the protrusion 42 is 20 [μm] (= 0.02 [mm]) or more.

Further, for example, assuming that the minimum protrusion height of the protrusion 42 is 20 [μm] (= 0.02 [mm]), the curvature radius R of the protrusion 42 is 1.85 [mm], and the root radius r is 0.6 [mm]. mm], 1.32 [mm] is substituted into the equation (6) as the center-to-center distance P satisfying the relationship of the equation (1). As a result, the retention amount Vg of the lubricant G is determined to be 0.0144... Mm ³ ≈0.014 [mm ³ ]. Therefore, it can be seen that the retention amount of the lubricant G is 0.01 [mm ³ ] or more under these conditions.

  When assembling the ball joint 11, the ball sheet 18 is first formed in advance by injection molding using a molding die (mold) not shown. At this time, since the outer periphery 41a and the inner periphery 41b of the pressure receiving part main body 41 of the pressure receiving part 32 are spherical and do not have a thickness distribution, the ball seat 18 is less likely to be sinked and easily omitted. Molded to a certain thickness. Further, since the protruding amount of the inner peripheral side protruding portion 36 at the lower end portion of the body portion 31 is smaller than that of the molding type, it is relatively easy to remove the mold without forcibly removing it after the molding.

  Next, a separately formed ball portion 28 is press-fitted into the ball seat 18 through the opening 34. At this time, since the protruding amount of the inner peripheral side protruding portion 36 of the body portion 31 of the ball seat 18 is smaller than that of the molded type, the ball portion 28 can be press-fitted relatively easily. The stud portion 29 may be formed integrally with the ball portion 28 or may be connected to the ball portion 28 later by welding or the like. Further, the lubricant G may be applied to the ball portion 28 press-fitted into the ball sheet 18 or may be injected into the ball sheet 18 in a later process.

  Then, the ball sheet 18 holding the ball portion 28 is press-fitted into the inner chamber 23 of the socket 16 separately formed by forging or casting. At this time, the outer peripheral protrusion 37 is deformed inward along the inner chamber 23 toward the central axis, so that the inner peripheral protrusion 36 is pressed against the outer peripheral surface 28a of the ball portion 28. Further, the plug 26 is inserted into the stud portion 29 of the ball stud 17 and attached to the socket 16, and the lower end side of the socket 16 is deformed by caulking to the center side to thereby deform the plug 26 into the inner edge of the socket opening 24 of the socket 16. Hold in the department. As a result, the ball seat 18 is fixed together with the ball stud 17 in a state where it is prevented from rotating in the inner chamber 23 of the socket 16.

  Thereafter, the dust cover 19 is inserted into the stud portion 29 of the ball stud 17, the upper end side of the dust cover 19 is fastened and fixed to the cover mounting portion 25 by the fixing member 45, and the lower end side of the dust cover 19 is fixed to the ball. The ball joint 11 is completed by fixing to the outer periphery of the stud portion 29 of the stud 17.

  In the ball joint 11 thus formed, when a load from the vehicle body is applied to the ball stud 17, the ball stud 17 swings in the left-right direction. At this time, the ball portion 28 is supported by the sliding contact portions 42a of the plurality of spherical projections 42, and a necessary amount of lubricant G is interposed between the ball portion 28 and the periphery of the projection 42 of the ball seat 18. As a result, the pressure receiving load and the lubrication state are controlled, and the ball portion 28 smoothly rotates (slides).

  As described above, in the present embodiment, the pressure receiving body 41 of the pressure receiving portion 32 that receives the compressive load in the axial direction of the ball stud 17 is formed by setting the outer periphery 41a and the inner periphery 41b to have a substantially constant thickness. In addition to being able to control the gap between the ball seat 18 (inner periphery 41b of the pressure receiving body main body 41) and the ball portion 28, the plurality of protrusions 42 projecting from the pressure receiving body 41 are suppressed. The spherical shape of the ball seat 18 prevents the ball seat 18 from being affected by the swaying (deflection) generated at the contact portion with the ball portion 28, and the fine recesses between the protrusions 42 are intentionally arranged to hold the lubricant G. The contact area with the outer peripheral surface 28a of the ball portion 28 can be increased. In other words, since the protrusions 42 are spherical, it is necessary to prevent the occurrence of poor lubrication such that the lubricant G to be originally interposed is entirely pushed out by the contact between the ball seat 18 and the ball portion 28. Space can be secured. As a result, the pressure formed load and the lubrication state can be controlled by controlling the gap formed between the ball seat 18 and the ball portion 28. Therefore, it is possible to suppress the occurrence of a part where the compressive load is concentrated and the surface pressure becomes excessively high, and it is possible to suppress the occurrence of creep deformation and cracks due to the excessive surface pressure. The resulting sheet destruction, that is, deterioration (sagging) of the ball sheet 18 can be suppressed.

  Then, by setting the numerical value obtained by dividing the sum of the root radius r, which is the radius at the position where the protrusion 42 is in contact with the pressure-receiving portion body 41, and the distance d by the root radius r, to be larger than 1.1, the protrusion 42 The amount of the lubricant G to be retained can be secured, and the lubricant G can be effectively retained.

  As a result, it is possible to achieve both reduction of the maximum input load per protrusion 42 and securing of the retained amount of the lubricant G.

  Further, the protrusion height H in a state where the protrusion 42 is deformed by contact with the ball portion 28 is set to 0.02 mm or more, thereby reducing the input load per protrusion 42 and the amount of the lubricant G retained. Securement can be ensured at the same time.

Furthermore, by setting the lubricant G per protrusion 42 to be 0.01 mm ³ or more, it is possible to more reliably achieve both a reduction in the input load per protrusion 42 and a securing amount of the lubricant G.

  By providing such a ball seat 18 to the ball joint 11, it is possible to suppress problems such as rattling with the ball portion 28 due to deterioration (sagging) of the ball seat 18, and repeated compression load and The ball joint 11 having excellent durability against sliding friction between the ball portion 28 and the ball seat 18 can be provided.

  In the above embodiment, the ball joint 11 is not limited to a vehicle suspension device, and can be used for, for example, a steering device or other devices.

  Furthermore, the ball joint 11 can be used not only for vehicles but also for other arbitrary uses.

  The present invention can be suitably used for a suspension device of a vehicle such as an automobile.

11 Ball joint
16 Socket which is housing
17 Ball stud
18 Ball seat as a bearing seat
28 Ball part
31 Torso
32 Pressure receiver
34 opening
41 Pressure sensor body
41a circumference
41b Inner circumference
42 Protrusion d Interval G Lubricant H Protrusion height r Root radius as radius

Claims (4)

A ball joint bearing seat that is housed in a housing and holds a ball stud ball portion via a lubricant,
A pressure receiving portion that contacts the ball portion in a slidable state while receiving a compressive load in the axial direction of the ball stud from the ball portion;
The ball stud has a body part positioned at one end side of the pressure receiving part, and has an opening part at the end part from which a part of the ball stud is led out.
The pressure receiving part is
A pressure receiving body having a substantially constant thickness, each of which has a spherical outer periphery and inner periphery;
A plurality of spherical projections provided on the inner periphery of the pressure-receiving unit main body, arranged in contact with the ball unit and spaced apart at a predetermined interval;
The ball joint bearing sheet, wherein a numerical value obtained by dividing a sum of a radius of the protrusion at a position in contact with the pressure receiving body and the interval by the radius is larger than 1.1. A housing;
The bearing seat according to claim 1 accommodated in the housing;
A lubricant disposed inside the bearing seat;
And a ball stud provided with a ball portion held by the bearing seat. The ball joint according to claim 2, wherein the protrusion has a protrusion height of 0.02 mm or more when deformed by contact with the ball portion. The ball joint according to claim 2 or 3, wherein the lubricant per protrusion is 0.01 mm ³ or more.

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