Patent Description:
A strut type suspension used for a front wheel of an automobile has structure in which a strut assembly comprising a piston rod and a hydraulic shock absorber is combined with a coil spring. When a steering is operated, the strut assembly is rotated together with the coil spring. Accordingly, to support a load applied to the strut type suspension while allowing smooth rotation of the strut assembly, usually a bearing is placed between an upper mount which is a mounting mechanism for mounting the strut assembly onto the automobile body, and an upper spring seat which is a spring seat for the upper end of the coil spring.

For example, the Patent Literature <NUM> discloses a slide bearing of synthetic resin as a bearing for a strut type suspension. This slide bearing comprises: an upper case of synthetic resin which is mounted on the side of an upper mount; a lower case of synthetic resin which is mounted on the side of an upper spring seat and is rotatably combined with the upper case; and a center plate of synthetic resin for smooth rotation between the upper case and the lower case. Here, a plurality of grooves functioning as lubricating grease reservoir are formed in a bearing surface of the center plate, and these grooves are filled with lubricating grease. Further, a dust seal is located in a ring-shaped space so as to close a gap which is formed between the upper case and the lower case and leads to the ring-shaped space.

According to the slide bearing of synthetic resin described in the Patent Literature <NUM>: the gap which is formed by combining the upper case and the lower case and leads to the outside of the ring-shaped space is closed; intrusion of dust, muddy water, or the like into the ring-shaped space can be prevented even under severe conditions; and thus it is possible to prevent deterioration of sliding performance owing to intrusion of dust, muddy water, or the like onto the bearing surface of the center plate placed in the ring-shaped space. <CIT> discloses a slide bearing with only one end of the outer dust seal abutting the opposite case, and without lubricating sheet. <CIT> discloses a slide bearing without any ring-shaped center plate. <CIT> discloses the possibility to add a lubricating sheet, but without and seal end.

In the slide bearing of synthetic resin described in the Patent Literature <NUM>, the dust seal comprises a cylindrical seal body and a ring-shaped lip part formed integrally with the seal body. In order to close the gap between the upper case and the lower case which leads to the ring-shaped space by contacting the lip part with a wall surface of the ring-shaped space, the dust seal is made of elastic material such as polyurethane resin, polyester elastomer, synthetic rubber, or the like. Further, to make the lip part come in contact with the wall surface of the ring-shaped space with appropriate force so that sealing performance is improved, a metal core is embedded in the seal body to increase the rigidity of the seal body. The slide bearing of synthetic resin described in the Patent Literature <NUM> requires addition of the dust seal having this metal core, and thus has a problem of cost increase. This problem occurs not only.

Translation in a strut type suspension but also in a suspension of another type such as a double wishbone type suspension, a multilink type suspension, an air suspension, or the like.

The present invention has been made taking the above conditions into consideration, and an object of the present invention is to provide a slide bearing which can prevent intrusion of dust, muddy water, or the like at low cost and, at the same time, has superior sliding performance.

To solve the above problems, the present invention provides a slide bearing according to claim <NUM>.

For example, the present invention provides a slide bearing, comprising:.

Here, the slide bearing may be, for example, one which supports a load of a vehicle body applied to a strut type suspension while allowing rotation of a strut-assembly of the strut type suspension, wherein:.

According to the present invention, the ring-shaped outer dust seal whose one end abuts against the upper case or the lower case is positioned on the outer peripheral side of the ring-shaped center plate placed between the upper case and the lower case, which are rotatably combined with each other, and the outer dust seal is formed integrally with the center plate. Accordingly, without embedding a metal core in the outer dust seal to increase the rigidity, it is possible to obtain sufficient sealing performance to close the gap formed between the upper case and the lower case between which the center plate is placed, owing to reaction force generated when the outer dust seal is deflected by the load of the object to be supported applied in the axial direction. Further, it is not necessary to prepare the outer dust seal as a separate part, and accordingly cost can be reduced. Further, in the present invention, the lubricating sheet is placed between the center plate and the upper case and/or between the center plate and the lower case, and thus it is possible to realize superior sliding performance even in the case where, for example, elastic material is used as material of the outer dust seal and material of the center plate formed integrally with the outer dust seal to give elasticity to the outer dust seal. Thus, according to the present invention, it is possible to prevent intrusion of dust, muddy water, or the like at lower cost and to realize superior sliding performance.

In the following, one embodiment of the present invention will be described.

<FIG> are respectively a plan view, a bottom view, and a front view of a slide bearing <NUM> according to the present embodiment, and <FIG> is an A-A cross-section view of the slide bearing <NUM> shown in <FIG>. Further, <FIG> is an enlarged view of the part A of the slide bearing <NUM> shown in <FIG>, and <FIG> is an enlarged view of the part B of the slide bearing <NUM> shown in <FIG>.

The slide bearing <NUM> of the present embodiment has a receiving hole <NUM> for receiving a strut assembly (not shown) of a strut type suspension, and supports a load of a vehicle body applied to the strut type suspension while allowing rotation of the strut assembly received in the receiving hole <NUM>. As shown in the figures, the slide bearing <NUM> comprises: an upper case <NUM>; a lower case <NUM> which is rotatably combined with the upper case <NUM>, to form a ring-shaped space <NUM> between the lower case <NUM> and the upper case <NUM>; a dust-seal-integrated center plate <NUM> which is placed in the ring-shaped space <NUM>; and a lubricating sheet <NUM> which is placed between the upper case <NUM> and the dust-seal-integrated center plate <NUM>; and, although not shown, lubricating grease which is filled in the ring-shaped space <NUM>.

The upper case <NUM> is formed of thermoplastic resin superior in sliding characteristics such as polyacetal resin impregnated with lubricating oil as needed. The upper case <NUM> is mounted on an upper support (not shown) as a mounting mechanism for the strut assembly of the strut type suspension onto the vehicle body in a state that the strut assembly is inserted in the upper case <NUM>.

<FIG> are respectively a plan view, a bottom view, and a front view of the upper case <NUM>, and <FIG> is a B-B cross-section view of the upper case shown in <FIG>.

As shown in the figures, the upper case <NUM> comprises: a ring-shaped upper case body <NUM> having an insertion hole <NUM> for inserting the strut assembly; an attaching surface <NUM> which is formed in the upper surface <NUM> of the upper case body <NUM> for attaching to the upper support; a ring-shaped groove <NUM> which is formed in the lower surface <NUM> of the upper case body <NUM> facing the lower case <NUM>, to form a ring-shaped space <NUM> when the upper case <NUM> is rotatably combined with the lower case <NUM>; a ring-shaped support object surface <NUM> which is formed in the groove bottom <NUM> of the ring-shaped groove <NUM> and rotates relative to a thrust bearing surface <NUM> (See <FIG>) of the below-mentioned thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>; and a snap fit part <NUM> for fitting the upper case <NUM> to the lower case <NUM>.

The snap fit part <NUM> has a cylindrical shape extending toward the lower case <NUM> along the direction of the axis O on the inner side (inner diameter side) from the below-mentioned inner peripheral surface <NUM> (See <FIG>) of the lower case <NUM>. The end portion <NUM> of the snap fit part <NUM> protrudes outward in the radial direction, to engage with an engaging portion <NUM> (See <FIG>) of the lower case <NUM>. The end portion <NUM> of the snap fit part <NUM> protrudes outermost toward the lower case <NUM>, on the side of the lower surface <NUM> of the upper case <NUM>.

On the groove bottom <NUM> of the ring-shaped groove <NUM>, a ring-shaped protective wall <NUM> is formed on the outer peripheral side of the support object surface <NUM>, to protrude in the direction of the lower surface <NUM> from the groove bottom <NUM>. This protective wall <NUM> encloses the outer peripheral side of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM> placed in the ring-shaped space <NUM>. And when the load is applied to the strut type suspension, the protective wall <NUM> prevents the lubricating grease filled in the ring-shaped space <NUM> from being pushed outward in the radial direction from the thrust bearing surface <NUM> of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>.

The lower case <NUM> is a resin body molded of thermoplastic resin such as polyamide. And the lower case <NUM> is fixed to an upper spring seat (not shown) as a spring seat for the upper end of a coil spring (not shown) of the strut type suspension in a state that the strut assembly of the strut type suspension is inserted in the lower case <NUM>.

<FIG> are respectively a plan view, a bottom view, and a front view of the lower case <NUM>, and <FIG> is a C-C cross-section view of the lower case <NUM> shown in <FIG>.

As shown in the figures, the lower case <NUM> comprises: a ring-shaped lower case body <NUM> having an insertion hole <NUM> for inserting the strut assembly; a ring-shaped projection <NUM> which is formed on the upper surface <NUM> of the lower case body <NUM> facing the upper case <NUM>, and is inserted into the ring-shaped groove <NUM> formed in the lower surface <NUM> of the upper case body <NUM> of the upper case <NUM> to form the ring-shaped space <NUM>, when the lower case <NUM> is rotatably combined with the upper case <NUM>; and a ring-shaped mud guard <NUM> which protrudes outward in the radial direction from the outer peripheral surface <NUM> of the lower case body <NUM>.

In the upper surface <NUM> of the ring-shaped projection <NUM>, a mounting surface <NUM> is formed for mounting the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>. Further, on the outer peripheral side of the mounting surface <NUM>, a plurality of arc-shaped rotation locks <NUM> are formed at regular intervals in the circumferential direction. In the circumferential direction, the rotation locks <NUM> engage with the below-mentioned connecting parts <NUM> (See <FIG>) of the dust-seal-integrated center plate <NUM>, to prevent rotation of the dust-seal-integrated center plate <NUM>. And the rotation locks <NUM> abut against the outer peripheral side of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>, to prevent deformation in the radially outward direction of the thrust bearing part <NUM>.

In the present embodiment, six rotation locks <NUM> are provided. However, it is sufficient to provide the rotation locks <NUM> equal in number to the connecting parts <NUM> of the dust-seal-integrated center plate <NUM>. In that case, it is favorable that the arc lengths of the rotation locks <NUM> are adjusted so that gaps <NUM> in which the connecting parts <NUM> are placed become equal in width.

On the side of the upper surface <NUM> of the lower case body <NUM>, the mud guard <NUM> protrudes from the outer peripheral surface <NUM> of the lower case body <NUM> outward in the radial direction beyond the outer peripheral surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>. The upper spring seal is fixed to the lower surface <NUM> of the mud guard <NUM>.

In the inner peripheral surface <NUM> of the lower case <NUM>, the engaging portion <NUM> is formed so as to engage with the end portion <NUM> of the snap fit part <NUM> of the upper case <NUM>.

The dust-seal-integrated center plate <NUM> is formed of elastic material superior in sliding characteristics such as polyolefin-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, or the like, and is added with lubricant such as polytetrafluoroethylene (PTFE), lubricating oil, silicone, or the like as needed. In cooperation with the lubricating sheet <NUM>, the dust-seal-integrated center plate <NUM> supports the load of the vehicle body which is applied to the strut type suspension and transmitted to the upper case <NUM>, while allowing free rotation between the upper case <NUM> and the lower case <NUM>. Further, the dust-seal-integrated center plate <NUM> closes the gap leading to the outside of the ring-shaped space <NUM>, to prevent intrusion of foreign matters such as dust into the ring-shaped space <NUM>.

<FIG> are respectively a plan view, a bottom view, and a front view of the dust-seal-integrated center plate <NUM>, <FIG> is a D-D cross-section view of the dust-seal-integrated center plater <NUM> shown in <FIG> is an enlarged view of the part C of the dust-seal-integrated center plate <NUM> shown in <FIG> is an enlarged view of the part D of the dust-seal-integrated center plate <NUM> shown in <FIG>.

As shown in the figures, the dust-seal-integrated center plate <NUM> comprises: a ring-shaped thrust bearing part <NUM>; a cylindrical radial bearing part <NUM> which is formed integrally with the thrust bearing part <NUM>, to protrude downward in the axial direction from the inner peripheral edge of the thrust bearing part <NUM>; a cylindrical outer dust seal part <NUM> which is positioned on the outer peripheral side of the thrust bearing part <NUM>; and the connecting parts <NUM> which connect the thrust bearing part <NUM> and the outer dust seal part <NUM>.

The thrust bearing part <NUM> comprises: a thrust bearing surface <NUM> formed in the upper surface <NUM>; and a ring-shaped grease groove <NUM> which is formed in the thrust bearing surface <NUM> and functions as a grease reservoir. When the dust-seal-integrated center plate <NUM> is placed on the lower case <NUM> such that the lower surface <NUM> of the thrust bearing part <NUM> comes in contact with the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>, the thrust bearing surface <NUM> faces the support object surface <NUM> formed in the ring-shaped groove <NUM> of the upper case <NUM> via the lubricating sheet <NUM>, and rotates relative to the support object surface <NUM>. Further, in the lower surface <NUM> on the opposite side to the upper surface <NUM> in which the thrust bearing surface <NUM> is formed, a ring-shaped recess <NUM> is formed at the position opposite to the grease groove <NUM>.

The radial bearing part <NUM> comprises: a radial bearing surface <NUM> formed in the inner peripheral surface <NUM>; and grease grooves <NUM> in the direction of the axis O which are formed in the radial bearing surface <NUM> and function as grease reservoirs. When the dust-seal-integrated center plate <NUM> is placed on the lower case <NUM> such that the lower surface <NUM> of the thrust bearing part <NUM> comes in contact with the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>, the radial bearing part <NUM> is inserted into the inside of the ring-shaped projection <NUM> so that the radial bearing surface <NUM> slides on the inner peripheral surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>.

As for the outer dust seal part <NUM>, one end <NUM> in the axial direction abuts against the protective wall <NUM> formed to protrude downward from the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>, and the other end <NUM> in the axial direction abuts against the upper surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>. As a result, the gap leading to the outside of the ring-shaped space <NUM> is closed, to prevent intrusion of foreign matters such as dust into the ring-shaped space <NUM>.

Further, the outer dust seal part <NUM> is formed to be thinner than the thrust bearing part <NUM> and the radial bearing part <NUM>, and the one end <NUM> which abuts against the upper case <NUM> is inclined outward in the radial direction seen in the axial cross-section. Accordingly, the one end <NUM> of the outer dust seal part <NUM> comes in contact with the protective wall <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>, while being deflected (See <FIG>). The reaction force of the outer dust seal part <NUM> acting against the load of the vehicle body applied to the strut type suspension gives sufficient sealing performance to close the gap leading to the outside of the ring-shaped space <NUM>.

The connecting parts <NUM> extend outward in the radial direction from the outer peripheral side of the thrust bearing part <NUM>, to connect with the outer dust seal part <NUM>. Further, the connecting parts <NUM> have narrower width in the circumferential direction than the gaps <NUM> between the rotation locks <NUM> themselves formed on the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case body <NUM> of the lower case <NUM>. And the connecting parts <NUM> are positioned in the respective gaps <NUM>, to place the thrust bearing part <NUM> on the mounting surface <NUM>. By engagement of the connecting parts <NUM> with the respective rotation locks <NUM> in the circumferential direction, the dust-seal-integrated center plate <NUM> is prevented from rotating. Although six connecting parts <NUM> are provided in the present embodiment, it is sufficient to provide at least one connecting part <NUM>.

The lubricating sheet <NUM> is formed of thermoplastic material superior in sliding characteristics such as fluorine resin (such as PTFE, modified PTFE obtained by copolymerizing tetrafluoroethylene (TFE) with a small amount of another material (comonomer), or the like), polyacetal resin, polyethylene resin, polyamide resin, polyphenylene sulfide resin, or the like, and, as needed, is added with lubricant such as PTFE (excepting the case where the thermoplastic material is PTFE or modified PTFE), lubricant such as lubricating oil, silicone, or graphite, and/or reinforcing material such as aramid fiber, glass fiber, carbon fiber, or the like. Or, the lubricating sheet <NUM> is formed of metal superior in sliding characteristics such as brass alloy. The lubricating sheet <NUM> is a ring-shaped member, and is placed between the support object surface <NUM> formed in the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case <NUM> and the thrust bearing surface <NUM> of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>. Owing to this arrangement, the thrust bearing surface <NUM> can rotate relative to the support object surface <NUM> via the lubricating sheet <NUM>.

<FIG> are respectively a plan view and a bottom view of the lubricating sheet <NUM>, and <FIG> is an E-E cross-section view of the lubricating sheet <NUM> shown in <FIG>.

As shown in the figures, the lubricating sheet <NUM> comprises: a sliding surface <NUM> which is formed in the upper surface <NUM>, to slide on the support object surface <NUM> formed in the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>; and a sliding surface <NUM> which is formed in the lower surface <NUM>, to slide on the thrust bearing surface <NUM> of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>. The thickness of the lubricating sheet <NUM> depends on the material used, and, for example, <NUM> - <NUM>, and favorably <NUM> - <NUM>. Further, it is favorable that the lubricating sheet <NUM> is flat in both the front and back surfaces.

In the slide bearing <NUM> of the above-described configuration of the present embodiment, the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM> is mounted on the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>, in a state that the dust-seal-integrated center plate <NUM> is prevented from rotating owing to engagement of the connecting parts <NUM> in the circumferential direction with the rotation locks <NUM> formed on the mounting surface <NUM>. And the thrust bearing surface <NUM> of the thrust bearing part <NUM> rotates relative to the support object surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM> via the lubricating sheet <NUM>. Further, the radial bearing part <NUM> is inserted into the inside of the ring-shaped projection <NUM>, and the radial bearing surface <NUM> of the radial bearing part <NUM> slides on the inner peripheral surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>. Accordingly, the dust-seal-integrated center plate <NUM> is supported by the upper spring seat fixed to the lower surface <NUM> of the mud guard <NUM> of the lower case <NUM> and by the coil spring of the strut type suspension, and thus supports the load of the vehicle body applied to the strut type suspension which is transmitted to the upper case <NUM>, while allowing rotation between the upper case <NUM> and the lower case <NUM>.

Hereinabove, one embodiment of the present invention has been described.

In the present embodiment, the dust-seal-integrated center plate <NUM> is placed in the ring-shaped space <NUM> formed by combining the upper case <NUM> with the lower case <NUM> such that the one end <NUM> in the axial direction of the outer dust seal part <NUM> abuts against the protective wall <NUM> in the ring-shaped groove <NUM> of the upper case <NUM> and the other end <NUM> in the axial direction abuts against the upper surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>. Owing to this arrangement, the reaction force of the outer dust seal part <NUM> acting against the load of the vehicle body applied to the strut type suspension gives sufficient sealing performance to close the gap leading to the outside of the ring-shaped space <NUM>, without embedding a metal core in the outer dust seal part <NUM> to increase the rigidity.

Further, in the present embodiment, the outer dust seal part <NUM> is connected to the thrust bearing part <NUM> via the connecting parts <NUM> extending outward in the radial direction from the outer peripheral side of the thrust bearing part <NUM>, and the outer dust seal part <NUM> is formed integrally with the thrust bearing part <NUM>. Accordingly, it is not necessary to provide the outer dust seal part <NUM> as a separate part, and, as a result, cost can be reduced.

Further, in the present embodiment, the lubricating sheet <NUM> is placed between the thrust bearing surface <NUM> of the thrust bearing part <NUM> and the support object surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>. Accordingly, even if elastomer is used as the material of the dust-seal-integrated center plate <NUM> to give elasticity to the outer dust seal part <NUM>, it is possible to realize superior sliding performance.

Thus, according to the present embodiment, it is possible to prevent intrusion of dust, muddy water, or the like at lower cost and to realize superior sliding performance.

Further, in the present embodiment, the dust-seal-integrated center plate <NUM> is provided with the cylindrical radial bearing part <NUM> formed integrally with the thrust bearing part <NUM>, to protrude downward in the axial direction from the inner peripheral edge of the thrust bearing part <NUM>, so that the radial bearing surface <NUM> slides on the inner peripheral surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>. Thus, according to the present embodiment, it is possible to support the load in the radial direction in addition to the load of the vehicle body in the thrust direction, while allowing rotation between the upper case <NUM> and the lower case <NUM>.

Further, in the present embodiment, the ring-shaped grease groove <NUM> functioning as a grease reservoir is formed in the thrust bearing surface <NUM> of the thrust bearing part <NUM>. Accordingly, it is possible to hold more lubricating grease on the thrust bearing surface <NUM>. As a result, according to the present invention, the thrust bearing surface <NUM> is covered with lubricating grease film, and it is possible to support over a longer period of time the load of the vehicle body applied to the strut type suspension, while allowing smooth rotation of the strut assembly of the strut type suspension.

Further, in the present embodiment, in the lower surface <NUM> on the opposite side to the upper surface <NUM> in which the thrust bearing surface <NUM> is formed, the ring-shaped recess <NUM> is formed at the position opposite to the grease groove <NUM> of the thrust bearing surface. Accordingly, it is possible to prevent that force applied from the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM> to the thrust bearing part <NUM> raises the groove bottom of the grease groove <NUM> of the thrust bearing surface <NUM> toward the upper case <NUM>. As a result, according to the present embodiment, it is possible to prevent the grease in the grease groove <NUM> from overflowing from the grease groove <NUM>, and thereby to keep the grease in the grease groove <NUM> and to maintain the sliding performance for a longer period.

Further, in the present embodiment, the arc-shaped rotation locks <NUM> are formed on the outer peripheral side of the mounting surface <NUM> formed in the upper surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>. These rotation locks <NUM> engages in the circumferential direction with the respective connecting parts <NUM> of the dust-seal-integrated center plate <NUM>, to prevent rotation of the dust-seal-integrated center plate <NUM>. And at the same time, the rotation locks <NUM> abut against the outer peripheral side of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>, to prevent deformation of the thrust bearing part <NUM> outward in the radial direction owing to the load of the vehicle body applied to the strut type suspension. Thus, according to the present embodiment, it is possible to prevent shift of the located position of the outer dust seal part <NUM> owing to deformation of the thrust bearing part <NUM> outward in the radial direction and to prevent decrease of the sealing performance of the outer dust seal part <NUM>.

Further, in the present embodiment, the lower case <NUM> is provided with the ring-shaped mud guard <NUM>, which protrudes from the outer peripheral surface <NUM> of the lower case body <NUM> on the side of the upper surface <NUM> of the lower case body <NUM> and outward in the radial direction beyond the outer peripheral surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>. Accordingly, the mud guard <NUM> can prevent muddy water or the like which jumps into the vehicle body from road surface while the vehicle is moving, so as to prevent more efficiently intrusion of the muddy water or the like into the ring-shaped space <NUM> of the slide bearing <NUM>.

Further, in the present embodiment, the snap fit part <NUM> which has the cylindrical shape extending toward the lower case <NUM> along the direction of the axis O and whose end portion <NUM> engages with the engaging portion <NUM> of the lower case <NUM> is formed on the inner peripheral side of the upper case <NUM> (on the inner side from the inner peripheral surface <NUM> of the lower case <NUM>). Here, the end portion <NUM> of the snap fit part <NUM> protrudes outward in the radial direction and protrudes outermost toward the lower case <NUM> on the side of the lower surface <NUM> of the upper case <NUM>. As a result, according to the present embodiment, it is possible to simplify the structure of the mold required for resin molding of the upper case <NUM>, in comparison with the case where a snap fit part is provided on the outer peripheral side of the upper case <NUM> and the end portion of the snap fit part is made to protrude inward in the radial direction. In detail, in the case where a snap fit part is provided on the outer peripheral side of the upper case <NUM> such that the end portion of the snap fit part protrudes inward in the radial direction, it is necessary to divide a mold into plural parts and is necessary to use slides to form the end portion of the snap fit part that protrudes inward in the radial direction. In contrast to this, in the present embodiment, a slide is not required and the mold structure can be simplified, since the end portion <NUM> of the snap fit part <NUM> is made to protrude outermost toward the lower case <NUM> on the side of the lower surface <NUM> of the upper case <NUM> and is made to protrude outward in the radial direction.

Further, in the present embodiment, the ring-shaped protective wall <NUM> is provided in the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case, to enclose the outer peripheral side of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM> placed in the ring-shaped space <NUM> formed by combining the upper case <NUM> with the lower case <NUM>. Owing to this protective wall <NUM>, it is possible to prevent the lubricating grease filled in the ring-shaped space <NUM> from being pushed outward in the radial direction from the thrust bearing surface <NUM> of the thrust bearing part <NUM>, when the load is applied to the strut type suspension. Accordingly, the thrust bearing surface <NUM> can be covered with the lubricating grease more reliably. Thus, according to the present embodiment, it is possible to support over a longer period of time the load of the vehicle body applied to the strut type suspension while allowing smooth rotation of the strut assembly of the strut type suspension.

The present invention is not limited to the above-described embodiment, and can be varied variously within the scope of the invention.

For example, in the above embodiment, the dust-seal-integrated center plate <NUM> is placed in the ring-shaped space <NUM> which is formed by combining the upper case <NUM> with the lower case <NUM>, such that the one end <NUM> in the axial direction of the outer dust seal part <NUM> abuts against the protective wall <NUM> in the ring-shaped groove <NUM> of the upper case <NUM> and the other end <NUM> in the axial direction abuts against the upper surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>. However, the present invention is not limited to this. It is sufficient that the dust-seal-integrated center plate <NUM> is placed in the ring-shaped space <NUM> such that the one end <NUM> in the axial direction of the outer dust seal part <NUM> is abutted against the protective wall <NUM> in the ring-shaped groove <NUM> of the upper case <NUM>. In this case also, since the thrust bearing part <NUM> formed integrally with the outer dust seal part <NUM> is fixed on the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>, sufficient sealing performance to close the gap leading to the outside of the ring-shaped space <NUM> can be obtained by reaction force generated by deflection of the outer dust seal part <NUM>. In this case, the other end <NUM> in the axial direction can be omitted.

Further, the above embodiment have been described taking the example in which one lubricating sheet <NUM> is placed between the support object surface <NUM> formed in the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case <NUM> and the thrust bearing surface <NUM> of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>. The present invention, however, is not limited to this.

For example, as seen in the variation 1a of the slide bearing <NUM> shown in <FIG>, a plurality of lubricating sheets <NUM> may be placed to overlap each other between the support object surface <NUM> and the thrust bearing surface <NUM>. When a plurality of lubricating sheets <NUM> are laid to overlap each other and slide on each other, it is possible to shorten slide lengths between the lubricating sheet <NUM> themselves, between the support object surface <NUM> and the lubricating sheet <NUM>, and between the thrust bearing surface <NUM> and the lubricating sheet <NUM>, and this decreases abrasion at each sliding location and extends lifetime.

Here, it is possible to provide a recess in the support object surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM> for receiving lubricating sheet <NUM>, so that at least one lubricating sheet <NUM> is placed in this recess. The depth of this recess is set to the thickness of lubricating sheet <NUM> or more, for example.

Further, just as, in the above embodiment, the lubricating sheet <NUM> is placed between the thrust bearing surface <NUM> of the thrust bearing part <NUM> and the support object surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>, a lubricating sheet may be placed also between the radial bearing surface <NUM> of the radial bearing part <NUM> and the inner peripheral surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>.

For example, as seen in the variation 1b of the slide bearing <NUM> shown in <FIG>, it is possible to use a lubricating sheet 6a which is formed such that a ring-shaped thrust sheet part <NUM> is integrated with a radial sheet part <NUM>. The thrust sheet part <NUM> is positioned between the thrust bearing surface <NUM> of the thrust bearing part <NUM> and the support object surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>. The radial sheet part <NUM> is formed integrally with the inner peripheral edge of the thrust sheet part <NUM> and is positioned between the radial bearing surface <NUM> of the radial bearing part <NUM> and the inner peripheral surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>. This arrangement can realize more superior sliding performance.

Further, in the above embodiment, the rotation locks <NUM> are formed on the outer peripheral side of the mounting surface <NUM> formed in the upper surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>. The present invention, however, is not limited to this. It is possible to form rotation locks on the outer peripheral side of the support object surface <NUM> formed in the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>, and to make these rotation locks to engage with the connecting parts <NUM> of the dust-seal-integrated center plate <NUM>, so as to prevent rotation of the dust-seal-integrated center plate <NUM>. At the same time, these rotation locks may be abuts against the outer peripheral side of the thrust bearing part <NUM> of the dust-seal-integrated center plate <NUM>, to prevent deformation of the thrust bearing part <NUM> outward in the radial direction owing to the load of the vehicle body applied to the strut type suspension. In this case, a thrust bearing surface is formed in the lower surface <NUM> of the thrust bearing part <NUM>, and this thrust bearing surface is made to come in slidable contact with the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>.

Further, in the above embodiment, the one end <NUM> in the axial direction of the outer dust seal part <NUM> of the dust-seal-integrated center plate <NUM> is made to abut against the protective wall <NUM> which is formed to protrude downward from the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case <NUM>, in order to abut against the groove bottom <NUM> of the ring-shaped groove <NUM>. The present invention, however, is not limited to this. For example, as seen in the variation <NUM> of the slide bearing <NUM> shown in <FIG>, the one end <NUM> of the outer dust seal part <NUM> may be directly abutted against the groove bottom <NUM> of the ring-shaped groove <NUM>.

Further, in the above embodiment, the one end <NUM> of the outer dust seal part <NUM> which abuts on the side of the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case <NUM> is inclined outward in the radial direction seen in the axial cross-section of the dust-seal-integrated center plate <NUM> (See <FIG>). The present invention, however, is not limited to this. It is sufficient that, seen in the axial cross-section, at least one of both the ends <NUM> and <NUM> of the outer dust seal part <NUM> is inclined outward or inward in the axial direction.

For example, as seen in the variation 1c of the slide bearing <NUM> shown in <FIG>, it is possible to use a dust-seal-integrated center plate 4a having an outer dust seal part 42a whose both ends are inclined outward in the radial direction seen in the axial cross-section. Or, as seen in the variation 1d of the slide bearing <NUM> shown in <FIG>, it is possible to use a dust-seal-integrated center plate 4b having an outer dust seal part 42b whose end <NUM> abuts on the side of the upper surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM> is inclined inward in the radial direction seen in the axial cross-section.

Further, if there is a possibility that dust, muddy water, or the like intrudes into the ring-shaped space <NUM> through the gap <NUM> (See <FIG>) between the inner peripheral surface <NUM> of the ring-shaped groove <NUM> of the upper case <NUM> and the inner peripheral surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>, a dust seal may be added to close this gap <NUM>. For example, as seen in the variation 1e of the slide bearing <NUM> shown in <FIG>, it is possible to use a dust-seal-integrated center plate 4c with which an inner dust seal part <NUM> to close the gap <NUM> leading to the ring-shaped space <NUM> is formed integrally at the end <NUM> of the radial bearing part <NUM> on the side of the lower case <NUM>.

Further, in the above embodiment, as in the thrust bearing surface <NUM> of the thrust bearing part <NUM>, a grease groove functioning as a grease reservoir may be formed also in the radial bearing surface <NUM> of the radial bearing part <NUM>. For example, as seen in the variation 1f of the slide bearing <NUM> shown in <FIG>, it is possible to use a dust-seal-integrated center plate 4d having a radial bearing part 41a whose radial bearing surface <NUM> has a ring-shaped grease groove <NUM> functioning as a grease reservoir formed therein.

Further, in the above embodiment, the dust-seal-integrated center plate <NUM> is placed and fixed on the lower case <NUM>. However, the dust-seal-integrated center plate <NUM> may be placed rotatably on the lower case <NUM>. In other words, similarly to the upper surface <NUM> of the thrust bearing part <NUM>, a thrust bearing surface may be formed also in the lower surface <NUM> of the thrust bearing part <NUM>, so that this thrust bearing surface comes in slidable contact with the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>. In this case, the rotation locks <NUM> positioned on the outer peripheral side of the mounting surface <NUM> of the ring-shaped projection <NUM> are omitted. Further, the recess <NUM> is not needed in the lower surface <NUM> of the thrust bearing part <NUM>. Here, to hold more lubricating grease in the thrust bearing surface formed in the lower surface <NUM> of the thrust bearing part <NUM>, a grease groove may be formed also in this thrust bearing surface. Further, at least one lubricating sheet <NUM> may be placed also between the thrust bearing surface formed in the lower surface <NUM> of the thrust bearing part <NUM> and the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>. Further, it is favorable that both the ends <NUM> and <NUM> of the outer dust seal part <NUM> of the dust-seal-integrated center plate <NUM> are inclined, so that both the ends <NUM> and <NUM> are respectively abutted against the groove bottom <NUM> of the ring-shaped groove <NUM> of the upper case <NUM> and the upper surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>.

Further, in the above embodiment, the dust-seal-integrated center plate <NUM> may be formed integrally with the lower case <NUM>. In this case, it is not necessary to form the arc-shaped rotational locks <NUM> on the outer peripheral side of the mounting surface <NUM> of the lower case <NUM>. Further, in the ring-shaped space <NUM> formed by combining the upper case <NUM> with the lower case <NUM>, the dust-seal-integrated center plate <NUM> formed integrally with the lower case <NUM> is positioned in the ring-shaped space <NUM> such that the one end <NUM> in the axial direction of the outer dust seal part <NUM> abuts against the groove bottom <NUM> including the protective wall <NUM> in the ring-shaped groove <NUM> of the upper case <NUM>.

Or, in the above embodiment, the dust-seal-integrated center plate <NUM> may be formed integrally with the upper case <NUM>. In this case also, it is not necessary to form the arc-shaped rotation locks <NUM> on the outer peripheral side of the mounting surface <NUM> of the lower case <NUM>. Further, the lubricating sheet <NUM> is placed between the dust-seal-integrated center plate <NUM> formed integrally with the upper case <NUM> and the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>. Further, in the ring-shaped space <NUM> formed by combining the upper case <NUM> with the lower case <NUM>, the dust-seal-integrated center plate <NUM> formed integrally with the upper case <NUM> is positioned in the ring-shaped space <NUM> such that the other end <NUM> in the axial direction of the outer dust seal part <NUM> abuts against the upper surface <NUM> of the ring-shaped projection <NUM> of the lower case <NUM>.

Further, in the above embodiment, the ring-shaped recess <NUM> is formed at the position opposite to the grease groove <NUM> of the thrust bearing surface <NUM> in the lower surface <NUM> on the opposite side to the upper surface <NUM>. The present invention, however, is not limited to this. The lower surface <NUM> of the thrust bearing part <NUM> may be a flat surface. In this case also, similar effects to those of the above embodiment can be obtained except for the effect owing to the ring-shaped recess <NUM>. Further, instead of providing the ring-shaped recess <NUM> in the lower surface <NUM> of the thrust bearing part <NUM>, a ring-shaped recess may be provided in the mounting surface <NUM> of the ring-shaped projection <NUM> of the lower case. In this case, similar effects to those of the above embodiment can be obtained.

Further, the above embodiment have been described taking the example where the slide bearing of the present embodiment is applied to the strut type suspension. The present invention, however, is limited to the scope defined by the appended claims. Without being limited to the strut type suspension, the slide bearing of the present invention can be widely applied to slide bearings which support load while allowing rotation in various mechanisms including a double wishbone type suspension, a multilink type suspension, an air suspension, or the like.

Claim 1:
A slide bearing, comprising:
an upper case (<NUM>) having a ring-shaped groove (<NUM>) formed in a lower surface (<NUM>) of an upper case body (<NUM>) of the upper case;
a lower case (<NUM>), which is rotatably combined with the upper case and has a ring-shaped lower case body (<NUM>) having an insertion hole (<NUM>) for inserting the strut assembly, and has a ring-shaped projection (<NUM>) which is formed in an upper surface (<NUM>) of the lower case facing the upper case and is inserted into the ring-shaped groove formed in the lower surface facing the lower case in order to form a ring-shaped space (<NUM>), the lower case having a ring-shaped mud guard (<NUM>) which protrudes outward in a radial direction from an outer peripheral surface of the lower case;
a ring-shaped center plate (<NUM>; 4a-d) which is placed between the upper case and the lower case; and
a ring-shaped outer dust seal (<NUM>) which is positioned on an outer peripheral side of the center plate;
wherein
the slide bearing further comprises a ring-shaped lubricating sheet (<NUM>; 6a) which is placed between the center plate and the upper case and/or between the center plate and the lower case;
the ring-shaped outer dust seal has one end (<NUM>) in the axial direction inclined outward in the radial direction and abutting, while being bent, directly against a groove bottom (<NUM>) of the ring-shaped groove of the upper case or against a protective wall (<NUM>) formed to protrude downward from the groove bottom of the ring-shaped groove of the upper case and another end (<NUM>) in the axial direction abutting against an upper surface (<NUM>) of the ring-shaped projection of the lower case;
the center plate has a connecting part (<NUM>) which extends outward in the radial direction from the outer peripheral side of the center plate and connects with the outer dust seal; and
at least one of front and back surfaces (<NUM>, <NUM>) of the lubricating sheet has a sliding surface (<NUM>) which slides on a counter surface facing the lubricating sheet.