JP6978965B2 - shock absorber - Google Patents

Description

The present invention relates to a shock absorber.

In Patent Document 1, as a method of assembling a shock absorber, a seat, a rod guide assembly, and a sealing member are laminated in this order on the upper side of a retaining ring provided on the inner circumference of the cylinder, and the upper end portion of the cylinder is crimped inward. It is stated that.

Japanese Unexamined Patent Publication No. 2015-218819

However, in the shock absorber described in Patent Document 1, when stacking the seat, the rod guide assembly, and the sealing member, there is a possibility that erroneous assembly may occur in which the parts are erroneously arranged in the opposite direction and assembled to the cylinder. rice field.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent the occurrence of erroneous assembly.

The first invention comprises a cylinder, a piston that divides the inside of the cylinder into an extension side chamber and a compression side chamber, a piston rod connected to the piston, and a seal member that slides on the outer periphery of the piston rod to prevent leakage of working fluid. A seal unit having a seal holding member for holding the seal member, a support member for partitioning the extension side chamber side and supporting the seal unit, and a position defining portion provided on the inner circumference of the cylinder to define the axial position of the support member. The support member is provided with a caulking portion formed at the end of the cylinder and for fixing the support member and the seal unit in a laminated state between the position-defining portion and the support member. The support member has a protrusion that protrudes toward the extension side chamber side on the center side from the position where it abuts on the position defining portion, and the support member is inserted into the cylinder with the front and back sides of the support member in the first direction. Occasionally, the surface opposite to the surface on which the protrusion is provided comes into contact with the seal holding member, the rigidity of the seal holding member is higher than the rigidity of the seal member, and the front and back of the support member are in the second direction opposite to the first orientation. It is a shock absorber characterized in that the tip end portion of the protruding portion comes into contact with the seal holding member when it is inserted into the cylinder in the direction of.

In the first invention, the protrusion of the cylinder end portion when the support member is placed on the position defining portion in the correct orientation, and the cylinder end portion when the support member is placed on the positioning portion in the wrong orientation. Since it is possible to make a difference from the output of the cylinder, it is possible to easily determine the incorrect assembly of the support member.

The second invention is characterized in that the support member is a bearing unit having a bearing in which the outer periphery of the piston rod is in sliding contact with the inner circumference and a bearing holding member for holding the bearing.

In the second invention, it is possible to make the protrusion of the cylinder end when the bearing unit is arranged in the correct orientation different from the protrusion of the cylinder end when the bearing unit is arranged in the wrong orientation. Therefore, it is possible to easily determine the incorrect assembly of the bearing unit.

A third aspect of the invention further comprises an elastically deformable annular rebound cushion provided on the outer periphery of the piston rod and having a contact surface that comes into contact with the support member when the shock absorber is fully extended, and the protrusion is the maximum extension of the shock absorber. It is characterized by occasionally contacting the outer periphery of the rebound cushion.

In the third invention, since the radial deformation of the rebound cushion can be suppressed by the protruding portion, the durability of the rebound cushion can be improved.

The fourth invention is characterized in that the protrusion is provided along the circumferential direction.

In the fourth invention, since the radial deformation of the rebound cushion can be uniformly suppressed by the protruding portion, the durability of the rebound cushion can be improved more effectively.

A fifth aspect of the invention is characterized in that the inner diameter of the base end portion of the protruding portion is larger than the outer diameter of the contact surface of the rebound cushion in the non-elastically deformed state.

In the fifth invention, the impact of the shock absorber can be effectively alleviated by expanding the rebound cushion in the radial direction when the shock absorber is fully extended.

In the sixth aspect of the invention, the support member is provided with a communication passage for transmitting the pressure of the extension side chamber to the seal member, and a part of the opening on the extension side chamber side of the connection passage is radially outside the radial inner edge of the protrusion. It is characterized by being placed in.

A seventh aspect of the invention is characterized in that the protrusions are arcuate, a plurality of protrusions are provided along the circumferential direction, and openings on the extension side chamber side of the communication passage are arranged between adjacent protrusions.

In the sixth and seventh inventions, it is possible to prevent the opening on the extension side chamber side of the communication passage from being blocked by the rebound cushion. Therefore, since the pressure of the extension side chamber can be continuously applied to the sealing member, the sealing performance of the sealing member can be maintained.

The eighth invention is an annular retaining ring in which a positioning portion is provided separately from the cylinder and has a circular cross section, and an annular groove into which the retaining ring is fitted is formed on the inner circumference of the cylinder. Is provided, and the axial length of the protruding portion is larger than the diameter of the cross section of the retaining ring.

In the eighth invention, since the axial length of the protruding portion is larger than the diameter of the cross section of the retaining ring, it is possible to more easily determine the incorrect assembly.

According to the present invention, it is possible to prevent the occurrence of erroneous assembly of the shock absorber.

It is sectional drawing of the shock absorber which concerns on 1st Embodiment of this invention. It is an enlarged sectional view which shows the rod guide assembly in the shock absorber which concerns on 1st Embodiment of this invention. It is a rear view which looked at the rod guide from the direction III of FIG. It is sectional drawing which shows the state which the bearing unit in the shock absorber which concerns on 1st Embodiment of this invention is arranged in a correct direction. It is sectional drawing which shows the state which the bearing unit in the shock absorber which concerns on 1st Embodiment of this invention is arranged in the wrong direction. It is a flowchart which shows the assembly procedure of the rod guide assembly of a shock absorber. It is sectional drawing which shows the state when the shock absorber which concerns on 1st Embodiment of this invention is extended most. It is sectional drawing which shows the state which the bearing unit in the shock absorber which concerns on 2nd Embodiment of this invention is arranged in the correct direction. It is sectional drawing which shows the state which the bearing unit in the shock absorber which concerns on 2nd Embodiment of this invention is arranged in the wrong direction. It is a rear view of the rod guide in the shock absorber which concerns on the modification of embodiment of this invention. It is a rear view of the rod guide in the shock absorber which concerns on another modification of embodiment of this invention. FIG. 3 is an enlarged cross-sectional view of an outer corner portion of a rod guide that engages with a support protrusion of a cylinder in a shock absorber according to still another modification of the embodiment of the present invention.

<First Embodiment>
Hereinafter, the shock absorber 10A according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the shock absorber 10A. As shown in FIG. 1, the shock absorber 10A is used in a vehicle such as an automobile, and the cylinder 1 is connected to a traveling device having wheels and axles, and a piston rod protruding from the cylinder 1 (hereinafter, also simply referred to as a rod). ) The end of 3 is set to an upright type connected to the vehicle body frame. Therefore, when an impact due to the unevenness of the road surface is input to the wheel, the rod 3 moves in and out of the cylinder 1 and the shock absorber 10A expands and contracts.

The shock absorber 10A may be used for a vehicle other than an automobile, or may be set to an inverted type in which the cylinder 1 is connected to the vehicle body side and the rod 3 is connected to the wheel side. In the following description, an upright shock absorber 10A will be described as an example, the tip of the rod 3 connected to the vehicle body frame will be shocked to the upper end of the shock absorber 10A, and the tip of the cylinder 1 connected to the traveling device will be shocked. The vertical direction of the shock absorber 10A is defined as the lower end portion of the absorber 10A.

The shock absorber 10A is a device that is interposed between the vehicle body frame and the traveling device to generate a damping force and suppress the vibration of the vehicle body. The shock absorber 10A includes a bottomed cylindrical cylinder 1, a rod guide assembly 100A fixed to the upper opening of the cylinder 1, a cylindrical rod 3 freely inserted into the cylinder 1, and a lower end of the rod 3. An annular piston 2 connected to the portion is provided.

The piston 2 is slidably provided in the cylinder 1 and divides the inside of the cylinder 1 into an extension side chamber 61 and a compression side chamber 62. The rod 3 is slidably supported by the rod guide assembly 100A. The extension side chamber 61 and the compression side chamber 62 are liquid chambers (action chambers) in which hydraulic oil as a working fluid is sealed.

The shock absorber 10A is a single-cylinder shock absorber provided with a free piston 4 that is slidably inserted into the cylinder 1 and defines the air chamber 63. A seal member 4a for maintaining the airtightness of the air chamber 63 is provided on the outer periphery of the free piston 4.

The lower end of the cylinder 1 on the air chamber 63 side is closed. A connecting member 1a for attaching the shock absorber 10A to the vehicle is provided at the lower end of the cylinder 1.

When the shock absorber 10A contracts and the rod 3 enters the cylinder 1, the free piston 4 moves to the air chamber 63 side, and the gas in the air chamber 63 is compressed by the volume of the rod 3 that has entered. When the shock absorber 10A extends and the rod 3 exits from the cylinder 1, the free piston 4 moves to the compression side chamber 62 side, and the gas in the air chamber 63 expands by the volume of the ejected rod 3. As a result, the volume change in the cylinder 1 when the shock absorber 10A is operated is compensated.

The upper end of the rod 3 extends from the cylinder 1, and the lower end of the rod 3 is inserted into the cylinder 1. In the rod 3, a screw 3a for attaching the shock absorber 10A to the vehicle is formed at the upper end portion, and a male screw 3b into which the nut 8 is screwed is formed at the lower end portion.

The piston 2 has passages 2a and 2b that communicate the extension side chamber 61 and the compression side chamber 62. A damping valve 5 having a plurality of annular leaf valves is provided on the extension side chamber 61 side of the piston 2. A damping valve 6 having a plurality of annular leaf valves is provided on the compression side chamber 62 side of the piston 2. The piston 2, the damping valve 5, and the damping valve 6 are fixed to the end of the rod 3 by the nut 8.

When the shock absorber 10A contracts, the damping valve 5 opens by the differential pressure between the extension side chamber 61 and the compression side chamber 62 to open the passage 2a, and at the same time, moves from the compression side chamber 62 to the extension side chamber 61 through the passage 2a. Gives resistance to the flow of oil. The damping valve 5 closes when the shock absorber 10A is extended to close the passage 2a. That is, the damping valve 5 is a damping force generating element that generates a damping force when the shock absorber 10A contracts.

The damping valve 6 opens when the shock absorber 10A is extended to open the passage 2b, and also provides resistance to the flow of hydraulic oil moving from the extension side chamber 61 to the compression side chamber 62 through the passage 2b. The damping valve 6 closes when the shock absorber 10A contracts to close the passage 2b. That is, the damping valve 6 is a damping force generating element that generates a damping force when the shock absorber 10A is extended.

An annular stopper 171 is fixed at a position separated upward by a predetermined distance from the piston 2 fixed to the rod 3, and the annular rebound cushion 170 is supported by the stopper 171. The rebound cushion 170 is formed of an elastic member such as rubber that can be elastically deformed, and is provided on the outer periphery of the rod 3. The rebound cushion 170 comes into contact with the rod guide 141 (see FIG. 2) described later when the shock absorber 10A is fully extended and elastically deforms to alleviate the impact of the shock absorber 10A when the shock absorber 10A is fully extended.

FIG. 2 is an enlarged cross-sectional view showing the rod guide assembly 100A. As shown in FIG. 2, the rod guide assembly 100A includes a dust seal unit 120 having a dust seal 122, an oil seal unit 130 having an oil seal 132, and a bearing unit 140 that pivotally supports the rod 3 so as to be movable in the axial direction. Have.

An annular groove 1c along the circumferential direction is formed on the inner circumference of the cylinder 1, and a retaining ring (spring pin) 109 provided separately from the cylinder 1 is fitted in the groove 1c. The retaining ring 109 is an annular member having a circular cross section, and is a positioning portion that engages with the bearing unit 140 and defines the axial position of the bearing unit 140. The bearing unit 140, the oil seal unit 130, and the dust seal unit 120 are laminated in this order on the upper side of the retaining ring 109 protruding from the inner peripheral surface of the cylinder 1, and the upper end portion of the cylinder 1 is crimped inward to form the crimped portion 1b. .. As a result, the bearing unit 140, the oil seal unit 130, and the dust seal unit 120 are fixed to the upper opening of the cylinder 1 in a laminated state between the caulking portion 1b and the retaining ring 109.

The bearing unit 140 has a bush (bearing) 142 in which the outer peripheral surface of the rod 3 is in sliding contact with the inner peripheral surface, and a rod guide 141 as a bearing holding member for holding the bush 142. The bush 142 is coated with a resin such as polytetrafluoroethylene (PTFE) on the inner peripheral surface of a cylindrical portion (bare metal portion) formed of a metal in a cylindrical shape. The bush 142 is press-fitted into the through hole 160 provided in the rod guide 141.

The dust seal unit 120 has a metal insert member 121 and a rubber rubber member coated on the insert member 121, and the rubber member has a dust seal 122 and an outer peripheral seal 123. The dust seal 122 is in sliding contact with the outer peripheral surface of the rod 3 to prevent foreign matter such as dust and rainwater from entering the cylinder 1. The outer peripheral seal 123 comes into contact with the inner peripheral surface of the cylinder 1 to prevent hydraulic oil from leaking from the outer peripheral surface of the rod guide assembly 100A. The dust seal 122 and the outer peripheral seal 123 are connected by a connecting rubber portion (not shown).

The oil seal unit 130 has an oil seal 132 as a seal member that slides into contact with the outer peripheral surface of the rod 3 to prevent leakage of hydraulic oil, and a seal member provided on the radial outer side of the oil seal 132 to hold the oil seal 132. It has a seal holder 133, and a seal housing 131 as a seal holding member for holding the oil seal 132 and the seal holder 133.

The metal seal housing 131 is provided with a seal accommodating recess 134, which is a concave seal accommodating portion for accommodating the oil seal 132 and the seal holder 133. The seal accommodating recess 134 has a small-diameter recess 135 and a large-diameter recess 136 having an inner diameter larger than that of the small-diameter recess 135, and exhibits a stepped shape in which a lower end surface (end surface on the bearing unit 140 side) is opened. The seal holder 133 is held in contact with the bottom surface and side surface of the large-diameter recess 136 and the rod guide 141. The oil seal 132 is held by the seal holder 133 in a state of being pressed against the bottom surface 135a of the small diameter recess 135 and the outer peripheral surface of the rod 3.

The seal housing 131 is formed with an insertion hole 138 through which the rod 3 is inserted. The insertion hole 138 is a through hole that penetrates in the axial direction from the bottom surface 135a of the small diameter recess 135 to the upper end surface of the seal housing 131. An annular gap is formed between the inner peripheral surface of the insertion hole 138 and the outer peripheral surface of the rod 3.

The annular oil seal 132 is inserted into the small diameter recess 135, and the annular seal holder 133 is press-fitted into the large diameter recess 136. The oil seal 132 is formed of an elastic member such as fluororubber. The seal holder 133 is formed of an elastic member such as nitrile rubber.

The rod guide 141 is arranged on the retaining ring 109, partitions the extension side chamber 61, and supports the oil seal unit 130 from below. That is, in the present embodiment, the bearing unit 140 having the rod guide 141 is configured as a support member for supporting the seal housing 131 of the oil seal unit 130. The rod guide 141 has a contact portion 143 that contacts the seal holder 133 and a non-contact portion 144 that is separated from the seal holder 133 on the end surface (the end surface on the oil seal unit 130 side) opposite to the extension side chamber 61. Have.

The contact portion 143 contacts the outer peripheral portion of the seal holder 133 and the seal housing 131. The non-contact portion 144 is axially separated from the inner peripheral portion of the seal holder 133. An oil chamber 151 is provided between the oil seal unit 130 and the bearing unit 140. The oil chamber 151 is defined as a substantially annular pressure chamber by the rod guide 141, the lower end surface of the oil seal unit 130, and the outer peripheral surface of the rod 3. An annular groove 147 recessed in the axial direction is formed in the oil chamber 151. The annular groove 147 is a recess for positively collecting foreign matter (contamination) in the oil chamber 151, and suppresses foreign matter from accumulating around the rod 3.

The rod guide 141 is formed with a communication passage 146 that connects the oil chamber 151 and the extension side chamber 61. The communication passage 146 is composed of a through-passage 146a that axially penetrates the rod guide 141 and a radial passage 146b that extends radially to the end surface of the rod guide 141 facing the seal housing 131. The communication passage 146 guides the hydraulic oil of the extension side chamber 61 to the oil chamber 151, and transmits the pressure on the extension side chamber 61 side to the seal holder 133 and the oil seal 132.

The hydraulic pressure of the extension side chamber 61 guided to the oil chamber 151 acts on the end surface of the seal holder 133, and the seal holder 133 is compressed in the axial direction and bulges in the radial direction. Therefore, the oil seal 132 is pressed against the outer peripheral surface of the rod 3 and the bottom surface 135a of the small diameter recess 135. As a result, the outer peripheral surface of the rod 3 is sealed by the oil seal 132.

FIG. 3 is a rear view of the rod guide 141 as viewed from the direction III of FIG. The cross section of the rod guide 141 in FIG. 2 shows a cross section along the line II-II in FIG. As shown in FIGS. 2 and 3, the rod guide 141 is an annular member. Hereinafter, as shown in FIG. 2, the front and back surfaces of the rod guide 141 are defined with the upper surface as the front surface 141f and the lower surface as the back surface 141b when the rod guide assembly 100A is properly assembled.

In the rod guide 141, the direction in which the front surface 141f is on the upper side and the back surface 141b is on the lower side is correct, and conversely, the direction in which the front surface 141f is on the lower side and the back surface 141b is on the upper side is the wrong direction. Since the rod guide 141 is an annular member, it can be inserted into the cylinder 1 even if the front and back sides are reversed. Therefore, when assembling the rod guide assembly 100A, there is a possibility that an erroneous assembly may occur in which the upper end portion of the cylinder is caulked with the rod guide 141 erroneously arranged in the opposite direction.

Therefore, in the first embodiment, in order to prevent the occurrence of erroneous assembly, when the rod guide 141 is inserted into the cylinder 1 in the wrong direction, the rod guide 141 is inserted into the cylinder 1 in the correct direction. The rod guide 141 is formed so that the protrusion X when crimping the upper end portion of the cylinder 1 is shorter than in the case of the above case. As a result, it is possible to determine the incorrect assembly by measuring the output allowance X in the pre-process of caulking the upper end portion of the cylinder. Hereinafter, it will be described in detail.

As shown in FIG. 2, the rod guide 141 is supported by the retaining ring 109 when the outer corner portion 148a abuts on the retaining ring 109. The rod guide 141 has a plurality of protrusions 110 that project from the back surface 141b facing the extension side chamber 61 side to the extension side chamber 61 side when the front and back surfaces of the rod guide 141 are inserted into the cylinder 1 in the correct direction.

As shown in FIGS. 2 and 3, the plurality of protrusions 110 are arranged at equal intervals along the circumferential direction. Each protrusion 110 is formed in an arc shape centered on the central axis of the rod 3 in a plan view. The protrusion 110 has a trapezoidal cross section, and is formed so that the width (dimension between the side surfaces 110b on both sides) decreases from the base end toward the tip surface 110a. The tip surface 110a is a flat surface orthogonal to the central axis of the rod 3, and the pair of both side surfaces 110b are tapered surfaces that are inclined so that the protrusion 110 becomes wider from the tip surface 110a toward the base end. ..

FIG. 4 is a cross-sectional view showing a state in which the bearing unit 140 in the shock absorber 10A is arranged in the correct orientation, and FIG. 5 is a cross-sectional view showing a state in which the bearing unit 140 in the shock absorber 10A is arranged in the wrong orientation. Is.

As shown in FIG. 4, when the bearing unit 140 is arranged on the retaining ring 109 in the correct orientation, the annular surface of the rod guide 141 that contacts the seal housing 131 is defined as the contact region A1. The tip surface 110a of the protrusion 110 is radially inside (center side) from the contact portion P0 where the rod guide 141 abuts on the retaining ring 109, and is from the inner circumference of the annular contact region A1. Is also formed so as to be located on the outer side in the radial direction. In other words, the protrusion 110 is formed so that the tip surface 110a is located in the annular contact region A1 when viewed from the axial direction.

As a result, as shown in FIG. 5, when the bearing unit 140 is incorporated in the cylinder 1 in the wrong direction, the tip surface 110a of the protrusion 110 comes into contact with the seal housing 131. Therefore, the allowance X is shorter than when the bearing unit 140 is arranged in the correct orientation.

When the protruding portion 110 is viewed from the axial direction, if a part of the tip surface 110a of the protruding portion 110 overlaps the annular contact region A1, the bearing unit 140 is arranged in the wrong direction. In addition, a part of the tip surface 110a of the protrusion 110 can be brought into contact with the seal housing 131. That is, the protruding portion 110 may be formed so that a part of the tip surface 110a is located radially outside the inner circumference of the annular contact region A1.

By the way, in a state where a plurality of parts are laminated on the retaining ring 109 prior to the caulking process of the upper end portion of the cylinder 1, a slight gap is formed between the laminated parts. Therefore, for example, the output X when crimping the upper end portion of the cylinder 1 becomes smaller as the total of the total tolerance of the stacked parts and the total of the gaps between the stacked parts becomes larger. .. That is, the output X of the cylinder unit changes according to the total of the tolerances of each component and the total of the gaps between the components.

In a conventional shock absorber, the diameter of the cross section of the retaining ring may be smaller than the total sum of the tolerances of each component and the total clearance (maximum value) of each component. In Patent Document 1, the seat 30 is provided with a hooking groove 30f in which the retaining ring 14 is in contact, and the distance from the bottom of the hooking groove 30f to the end surface of the outer peripheral portion 30b on the working chamber L side is smaller than the diameter of the cross section of the retaining ring 14. Is disclosed.

However, in the technique described in Patent Document 1, the distance from the bottom of the hook groove 30f in which the retaining ring 14 is in contact to the end face of the outer peripheral portion 30b on the working chamber L side is the total of the tolerances of each component and the gap (maximum) of each component. Value) less than the sum of the sum. Therefore, in the technique described in Patent Document 1, the protrusion X at the end of the cylinder when the seat 30 is arranged in the correct orientation and the cylinder when the seat 30 is arranged on the retaining ring 14 in the wrong orientation. The difference from the output X at the end is small, and it is not possible to determine the incorrect assembly of the sheet 30. That is, in the technique described in Patent Document 1, whether the difference in the output X between the case where it is arranged in the correct direction and the case where it is arranged in the wrong direction is due to the influence of the tolerance and the gap between the parts is erroneous assembly. It may not be possible to determine whether it is due to.

Therefore, if the protrusion height B1, which is the axial length of the protrusion 110, is smaller than the total of the tolerances of the stacked parts and the total gap (maximum value) between the stacked parts, It becomes difficult to make a wrong assembly judgment. Therefore, the protrusion height B1 of the protrusion 110 is set so that the tip surface 110a thereof is located below the lower end of the retaining ring 9 as shown in FIG. 4 so that the misassembly can be easily determined. Is preferable. Further, it is more preferable that the protrusion height B1 of the protrusion 110 is set to a dimension larger than the diameter of the cross section of the retaining ring 109. For example, the protrusion height B1 of the protrusion 110 is set to a dimension of 1 mm or more. As a result, the total of the tolerances of the stacked parts and the total of the gaps (maximum values) between the parts are greater than the total when the bearing unit 140 is placed in the correct orientation and in the wrong orientation. The bearing X can be changed, and the determination of the wrong assembly can be made more easily.

The method of assembling the rod guide assembly 100A of the shock absorber 10A according to the first embodiment will be described. FIG. 6 is a flowchart showing an assembly procedure of the rod guide assembly 100A of the shock absorber 10A. As shown in FIG. 6, the assembly method of the rod guide assembly 100A includes a preparation step S100, a positioning portion forming step S110, a bearing unit placement step S120, an oil seal unit placement step S130, and a dust seal unit placement step S140. A misassembly determination step S150 and a caulking process S160 are provided.

In the preparation step S100, each component constituting the rod guide assembly 100A is prepared. The bush 142 is press-fitted into the through hole 160 of the rod guide 141 to form the bearing unit 140. The oil seal 132 is inserted into the seal accommodating recess 134 of the seal housing 131, and then the seal holder 133 is inserted to form the oil seal unit 130. The insert member 121 is covered with a rubber member having a dust seal 122 and an outer peripheral seal 123 to form a dust seal unit 120.

In the positioning portion forming step S110, the retaining ring 109 is fitted into the groove 1c formed along the circumferential direction on the inner circumference of the cylinder 1.

In the bearing unit arrangement step S120, the bearing unit 140 is inserted inside the cylinder 1 from the upper opening of the cylinder 1, and the bearing unit 140 is placed on the retaining ring 109.

In the oil seal unit arranging step S130, the oil seal unit 130 is inserted into the inside of the cylinder 1 from the upper opening of the cylinder 1, and the oil seal unit 130 is placed on the bearing unit 140.

In the dust seal unit arranging step S140, the dust seal unit 120 is inserted into the inside of the cylinder 1 from the upper opening of the cylinder 1 and placed on the oil seal unit 130.

In the misassembly determination step S150, as shown in FIGS. 4 and 5, the output allowance X from the upper end of the insert member 121 of the dust seal unit 120 to the upper end of the cylinder 1 is measured, and the measured output allowance X is predetermined. It is determined whether or not the threshold value is Xt1 or more. The threshold value Xt1 is set to determine whether or not the bearing unit 140 is arranged in the correct orientation.

As shown in FIG. 4, when the bearing unit 140 is incorporated in the cylinder 1 in the correct orientation, the end face of the flat contact portion 143 comes into contact with the seal housing 131. At this time, the distance from the contact portion P0 between the retaining ring 109 and the outer corner portion 148a of the rod guide 141 to the contact surface between the contact portion 143 and the seal housing 131 is L0.

The outer corner portion 148b on the back surface 141b side of the rod guide 141 has the same shape as the outer corner portion 148a on the front surface 141f side of the rod guide 141. Therefore, as shown in FIG. 5, when the bearing unit 140 is incorporated in the cylinder 1 in the wrong direction, the outer corner portion 148b abuts on the retaining ring 109, and the retaining ring 109 abuts on the bearing unit 140 in the axial direction. The position of is specified. At this time, the distance from the contact portion P1 between the retaining ring 109 and the outer corner portion 148b of the rod guide 141 to the contact surface between the tip surface 110a of the protrusion 110 and the seal housing 131 is L1.

The distance L1 when the bearing unit 140 is assembled in the cylinder 1 in the wrong orientation is the protrusion height of the protrusion 110 as compared with the distance L0 when the bearing unit 140 is incorporated in the cylinder 1 in the correct orientation. It becomes longer by B1 (L1> L0, L1 = L0 + B1).

Therefore, the protrusion X1 when the bearing unit 140 is assembled in the cylinder 1 in the wrong orientation has a protrusion 110 as compared with the protrusion X0 when the bearing unit 140 is incorporated in the cylinder 1 in the correct orientation. The protrusion height B1 is shortened (X1 <X0, X1 = X0-B1).

The threshold value Xt1 is set to a value larger than X1 and smaller than X0 (X1 <Xt1 <X0). As shown in FIG. 6, in the misassembly determination step S150, when the measured output allowance X is equal to or greater than the threshold value Xt1, it is determined that the bearing unit 140 is arranged in the correct direction, and the process proceeds to the caulking process S160. If the measured output X is less than the threshold value Xt1 in the misassembly determination step S150, it is determined that the bearing unit 140 is arranged in the opposite direction (wrong direction), and the process proceeds to the unit take-out step S155.

In the unit take-out step S155, the dust seal unit 120, the oil seal unit 130, and the bearing unit 140 are taken out from the cylinder 1, and the process returns to the bearing unit arrangement step S120.

When it is determined in the misassembly determination step S150 that the bearing units 140 are arranged in the correct orientation, in the caulking process S160, the upper end portion of the cylinder 1 is caulked inward to form the caulking portion 1b. This completes the rod guide assembly 100A.

As described above, the protrusion 110 has the protrusion X (X = X0) at the end of the cylinder when the bearing unit 140 is arranged on the retaining ring 109 in the correct orientation, and the retaining ring 140 in the wrong orientation. It has a function of making the protrusion X (X = X1) of the cylinder end different from that when it is arranged on the 109. Thereby, in the misassembly determination step S150, the misassembly of the rod guide assembly 100A can be easily determined.

In addition to the above functions, the protrusion 110 has a function of improving the durability of the rebound cushion 170. FIG. 7 is a diagram showing a state when the shock absorber 10A is most extended. As shown in FIG. 7, when the shock absorber 10A is most extended, the rebound cushion 170 is elastically deformed when the annular contact surface 170a, which is the end surface facing the bearing unit 140, comes into contact with the back surface 141b of the rod guide 141. The inner diameter D1 of the base end portion of the protrusion 110 is larger than the outer diameter D2 of the contact surface 170a of the rebound cushion 170 in a state where it is not elastically deformed (D1> D2). Therefore, the rebound cushion 170 expands in the radial direction when the shock absorber 10A is fully extended, so that the impact of the shock absorber 10A can be effectively alleviated. Further, at the time of maximum extension of the shock absorber 10A, the outer periphery of the rebound cushion 170 expanded in the radial direction due to elastic deformation comes into contact with the inner side surface 110b of the protrusion 110, and its radial deformation is restricted. .. Since the rebound cushion 170 can be prevented from being excessively deformed, the durability of the rebound cushion 170 can be improved.

As described above, since the protruding portion 110 has a shape along the circumferential direction (see FIG. 3), the radial deformation of the rebound cushion 170 can be uniformly suppressed. Therefore, the durability of the rebound cushion 170 can be improved more effectively. As described above, the inner side surface 110b of the protrusion 110 is formed as a tapered surface. Therefore, the rebound cushion 170 is not damaged due to contact with the inner side surface 110b of the protrusion 110.

As shown in FIG. 3, the opening surface on the extension side chamber 61 side of the gangway 146a is arranged between the protrusions 110 adjacent to each other in the circumferential direction. Further, the opening surface on the extension side chamber 61 side of the gangway 146a is arranged radially outside the radial inner edge 110i of the protrusion 110. It is not necessary that all the opening surfaces of the through-passage 146a on the extension side chamber 61 side are arranged radially outside the radial inner edge 110i of the protrusion 110. That is, a part of the opening surface on the extension side chamber 61 side of the gangway 146a may be arranged radially outside the radial inner edge 110i of the protrusion 110.

This makes it possible to prevent the opening of the gangway 146a from being blocked by the rebound cushion 170 when the shock absorber 10A is fully extended, as shown in FIG. Therefore, since the pressure of the extension side chamber 61 can be continuously applied to the oil seal 132, the sealing performance of the oil seal 132 can be maintained. Further, on the back surface 141b of the rod guide 141, the region where the axial end surface of the rebound cushion 170 contacts can be a flat surface without unevenness such as an opening of the gangway 146a. This makes it possible to prevent the rebound cushion 170 from being damaged when the rebound cushion 170 collides with the rod guide 141. Therefore, the durability of the rebound cushion 170 can be improved.

According to the first embodiment described above, the following effects are obtained.

As shown in FIG. 4, when the front and back surfaces of the rod guide 141 are inserted into the cylinder 1 in the correct orientation, the rod guide 141 has a surface (front surface 141f) opposite to the surface (rear surface 141b) on which the protrusion 110 is provided. When the rod guide 141 is in contact with the seal housing 131 and the front and back of the rod guide 141 are inserted into the cylinder 1 in the wrong direction opposite to the correct direction, the tip surface 110a of the protrusion 110 is inserted into the seal housing 131. Formed to contact.

According to such a configuration, the protrusion X (X = X0) at the end of the cylinder when the bearing unit 140 is arranged on the retaining ring 109 in the correct orientation and the retaining ring 109 in the wrong orientation of the bearing unit 140. It is possible to make the protrusion X (X = X1) of the cylinder end different from the case where it is arranged above. As a result, it is possible to easily determine the erroneous assembly, and it is possible to prevent the occurrence of the erroneous assembly. As a result, it is possible to prevent oil leakage due to incorrect assembly.

<Second Embodiment>
The shock absorber 10B according to the second embodiment of the present invention will be described with reference to FIGS. 8 and 9. Hereinafter, the points different from those of the first embodiment will be mainly described, and in the drawings, the same configurations as those described in the first embodiment or the corresponding configurations are designated by the same reference numerals and the description thereof will be omitted. .. FIG. 8 is a cross-sectional view showing a state in which the bearing unit 240 in the shock absorber 10B is arranged in the correct orientation, and FIG. 9 is a cross-sectional view showing a state in which the bearing unit 240 in the shock absorber 10B is arranged in the wrong orientation. Is.

In the first embodiment, by providing the protrusion 110, the allowance X (X = X0) when the rod guide 141 is arranged in the correct direction and the allowance when the rod guide 141 is arranged in the wrong direction are provided. An example in which X (X = X1) is different from X (X = X1) has been described. On the other hand, in the second embodiment, the step portion 249 is formed on the rod guide 241 instead of the protruding portion 110 formed on the rod guide 141.

The step portion 249 is formed on the outer peripheral portion of the rod guide 241 over the entire circumference of the rod guide 241. The step portion 249 has a side surface 249b parallel to the axial direction and a bottom surface 249a orthogonal to the axial direction.

As shown in FIG. 9, the step portion 249 is formed so that its bottom surface 249a abuts on the retaining ring 109 when the rod guide 241 is arranged in the wrong direction. In the second embodiment, by forming the step portion 249, the contact portion 143 on the radial inner side of the step portion 249 is formed as the projecting portion 210.

That is, the rod guide 241 according to the second embodiment has a surface (rear surface) opposite to the surface (front surface 241f) on which the protrusion 210 is provided when the front and back surfaces of the rod guide 241 are inserted into the cylinder 1 in the wrong direction. 241b) comes into contact with the seal housing 131. Further, when the front and back surfaces of the rod guide 241 are inserted into the cylinder 1 in the correct direction, the tip surface 210a of the protruding portion 210 comes into contact with the seal housing 131.

The protrusion 210 is provided on the center side of the contact portion P2 that abuts on the retaining ring 109 when the rod guide 241 is inserted into the cylinder 1 in the wrong direction. The protrusion height B2 of the protrusion 210 is set so that the tip surface 210a thereof is located below the lower end of the retaining ring 109.

As shown in FIG. 8, when the bearing unit 240 is incorporated in the cylinder 1 in the correct orientation, the end face of the flat contact portion 143 comes into contact with the seal housing 131. At this time, the distance from the contact portion P0 between the retaining ring 109 and the outer corner portion 148a of the rod guide 141 to the contact surface between the contact portion 143 and the seal housing 131 is L0.

On the other hand, as shown in FIG. 9, when the bearing unit 240 is incorporated in the cylinder 1 in the wrong direction, the back surface 241b that the rebound cushion 170 originally contacts comes into contact with the seal housing 131.

As described above, a step portion 249 is formed on the outer peripheral portion of the rod guide 241 on the back surface 241b side. Therefore, when the bearing unit 240 is incorporated in the cylinder 1 in the wrong direction, the bottom surface 249a of the step portion 249 comes into contact with the retaining ring 109, and the bearing unit 240 is supported. The distance from the contact portion P2 between the retaining ring 109 and the step portion 249 of the rod guide 241 to the contact surface between the back surface 241b of the rod guide 241 and the seal housing 131 is L2.

The distance L2 when the bearing unit 240 is assembled in the cylinder 1 in the wrong orientation is shorter than the distance L0 when the bearing unit 240 is assembled in the cylinder 1 in the correct orientation (L2 <L0). ..

Therefore, the allowance X2 when the bearing unit 240 is assembled in the cylinder 1 in the wrong orientation is longer than the allowance X0 when the bearing unit 240 is assembled in the cylinder 1 in the correct orientation ( X2> X0).

The assembly procedure of the rod guide assembly 100B according to the second embodiment is the same as the assembly procedure of the rod guide assembly 100A according to the first embodiment. However, the misassembly determination process is performed as follows.

In the second embodiment, in the misassembly determination step, it is determined whether or not the measured output allowance X is less than the predetermined threshold value Xt2. The threshold value Xt2 is set to determine whether or not the bearing unit 240 is arranged in the correct orientation. The threshold value Xt2 is set to a value larger than X0 and smaller than X2 (X0 <Xt2 <X2).

In the misassembly determination step, when the measured output allowance X is less than the threshold value Xt2, it is determined that the bearing unit 240 is arranged in the correct direction, and the process proceeds to the caulking process S160. In the misassembly determination step, when the measured output allowance X is equal to or greater than the threshold value Xt2, it is determined that the bearing unit 240 is arranged in the opposite direction (wrong direction), and the process proceeds to the unit take-out step S155.

According to such a second embodiment, as in the first embodiment, when the bearing unit 240 is arranged on the retaining ring 109 in the correct orientation, the protrusion X (X = X0) at the end of the cylinder and the bearing The protrusion X (X = X2) at the end of the cylinder when the unit 240 is placed on the retaining ring 109 in the wrong direction can be different. As a result, it is possible to easily determine the erroneous assembly, and it is possible to prevent the occurrence of the erroneous assembly. As a result, it is possible to prevent oil leakage due to incorrect assembly.

The following modifications are also within the scope of the present invention, and the configurations shown in the modifications may be combined with the configurations described in the above-described embodiments, or the configurations described in the above-mentioned different embodiments may be combined, and the following differences may occur. It is also possible to combine the configurations described in the modified example.

<Modification 1>
In the first embodiment, the rod guide 141 has been described in which a plurality of protrusions 110 are provided along the circumferential direction at predetermined intervals, but the present invention is not limited thereto. For example, as shown in FIG. 10, the rod guide 341 may be provided with a single annular protrusion 310. Further, in the present modification 1, instead of the gangway 146a described in the first embodiment, a groove 346a extending in the axial direction is provided on the outer periphery of the rod guide 341. The groove 346a communicates with the radial passage 146b and constitutes a communication passage that guides the hydraulic oil of the extension side chamber 61 to the oil chamber 151. According to such a modification, the same effect as that described in the first embodiment is obtained.

<Modification 2>
In the first embodiment described above, an example in which the cross section of the protruding portion 110 is trapezoidal has been described, but the present invention is not limited thereto. For example, the cross section of the protrusion 110 may be semicircular. Further, a plurality of hemispherical protrusions may be provided.

<Modification 3>
In the above embodiment, an example in which the bearing units 140 and 240 are configured as a support member for supporting the seal housing 131 of the oil seal unit 130 has been described, but the present invention is not limited thereto. For example, as shown in FIG. 11, the bush 142 may be held in the seal housing 431 of the oil seal unit 430. That is, the oil seal unit 430 has a function as a bearing holding member for holding the bush (bearing) 142 in addition to the function as a seal holding member for holding the oil seal 132 and the seal holder 133. In this case, instead of the bearing units 140 and 240, a retainer 441 that supports the oil seal unit 430 is provided as a support member.

<Modification example 4>
In the above embodiment, an example in which the retaining ring 109 functions as a positioning portion that defines the axial position of the rod guides 141 and 241 has been described, but the present invention is not limited thereto. For example, as shown in FIG. 12, a support protrusion 509 as a positioning portion may be formed by projecting a part of the cylindrical cylinder 1 inward by roll caulking. The support protrusion 509 is formed, for example, with a semicircular cross section. The support protrusions 509 may be formed over the entire circumference of the cylinder 1, or may be formed in plurality at equal intervals in the circumferential direction.

<Modification 5>
In the above embodiment, the single-cylinder shock absorbers 10A and 10B have been described as an example, but the present invention is not limited thereto. The present invention may be applied to a double-cylinder shock absorber in which an air chamber is formed in a gap between two cylinders, a shock absorber in which a tank is provided outside the cylinder as an air chamber, and the like.

Hereinafter, the configurations, actions, and effects of the embodiments of the present invention will be collectively described.

The shock absorbers 10A and 10B are provided in the cylinder 1 in which the hydraulic oil is sealed, the piston 2 which is slidably provided in the cylinder 1 and divides the inside of the cylinder 1 into the extension side chamber 61 and the compression side chamber 62, and the cylinder 1. A seal unit having a piston rod 3 that is freely inserted and retracted and connected to the piston 2, an oil seal 132 that slides on the outer periphery of the piston rod 3 to prevent leakage of hydraulic oil, and a seal housing 131 that holds the oil seal 132. The oil seal unit 130), the support member (140, 240, 441) that partitions the extension side chamber 61 side and supports the oil seal unit 130, and the support member (140, 240, 441) provided on the inner circumference of the cylinder 1. A support member (140, 240, 441) and oil are formed between the positioning portion (109,509) that defines the axial position and the positioning portion (109,509) formed at the end of the cylinder 1. The support member (140, 240, 441) is provided with a caulking portion 1b for fixing the seal unit 130 in a laminated state, and the front and back sides of the support member (140, 240, 441) are inserted into the cylinder 1 in the first direction. At that time, the support member (140, 240, 441) has the projecting portions 110, 210, 310 protruding toward the extension side chamber 61 on the center side from the position where the position defining portion (109, 509) is in contact with the position defining portion (109, 509). When the front and back surfaces of the support member (140, 240, 441) are inserted into the cylinder 1 in the first direction, the surface opposite to the surface on which the protrusions 110, 210, 310 are provided comes into contact with the seal housing 131 to support the seal housing 131. When the front and back of the member (140, 240, 441) are inserted into the cylinder 1 in the second direction opposite to the first direction, the tips of the protrusions 110, 210, 310 come into contact with the seal housing 131.

In this configuration, the cylinder end allowance X and the support member (140, 240, 441) when the support member (140, 240, 441) is placed on the position defining portion (109, 509) in the correct orientation. Can be different from the protrusion X at the end of the cylinder when is placed on the positioning portion (109, 509) in the wrong orientation, so that the support member (140, 240, 441) is misassembled. Judgment can be made easily. As a result, it is possible to prevent the occurrence of erroneous assembly, and thus it is possible to prevent oil leakage due to erroneous assembly.

The shock absorbers 10A and 10B are bearing units 140 and 240 having rod guides 141,241 and 341 in which the support member holds the bush 142 and the bush 142 in which the outer periphery of the piston rod 3 is in sliding contact with the inner circumference thereof.

In this configuration, the cylinder end allowance X when the bearing units 140 and 240 are arranged in the correct orientation and the cylinder end allowance X when the bearing units 140 and 240 are arranged in the wrong orientation. , Can be made different, so that it is possible to easily determine the incorrect assembly of the bearing units 140 and 240.

The shock absorber 10A further comprises an elastically deformable annular rebound cushion 170 provided on the outer periphery of the piston rod 3 and having a contact surface 170a that comes into contact with the support member (140,441) when the shock absorber 10A is fully extended. The portions 110 and 310 come into contact with the outer periphery of the rebound cushion 170 when the shock absorber 10A is fully extended.

In this configuration, the protrusions 110 and 310 can suppress the radial deformation of the rebound cushion 170, so that the durability of the rebound cushion 170 can be improved.

The shock absorber 10A is provided with protrusions 110 and 310 along the circumferential direction.

In this configuration, the protrusions 110 and 310 can uniformly suppress the radial deformation of the rebound cushion 170, so that the durability of the rebound cushion 170 can be improved more effectively.

In the shock absorber 10A, the inner diameter D1 of the base end portions of the protruding portions 110 and 310 is larger than the outer diameter D2 of the contact surface 170a of the rebound cushion 170 in a state where the rebound cushion 170 is not elastically deformed.

In this configuration, the rebound cushion 170 expands in the radial direction when the shock absorber 10A is fully extended, so that the impact of the shock absorber 10A can be effectively alleviated.

In the shock absorber 10A, the support member (140, 441) is provided with a communication passage 146 that transmits the pressure of the extension side chamber 61 to the oil seal 132, and a part of the opening of the communication passage 146 on the extension side chamber 61 side is a protruding portion. It is arranged radially outside the radial inner edges 110i of 110 and 310.

The shock absorber 10A has a plurality of protrusions 110 having an arc shape and is provided along the circumferential direction, and an opening on the extension side chamber 61 side of the communication passage 146 is arranged between the adjacent protrusions 110.

With these configurations, it is possible to prevent the opening on the extension side chamber 61 side of the communication passage 146 from being blocked by the rebound cushion 170. Therefore, since the pressure of the extension side chamber 61 can be continuously applied to the oil seal 132, the sealing performance of the oil seal 132 can be maintained.

The shock absorbers 10A and 10B are annular retaining rings 109 having a positioning portion provided separately from the cylinder 1 and having a circular cross section, and the retaining ring 109 is fitted on the inner circumference of the cylinder 1. An annular groove 1c is provided, and the protrusion heights B1 and B2, which are the axial lengths of the protrusions 110, 210, and 310, are larger than the diameter of the cross section of the retaining ring 109.

In the eighth invention, since the protrusion heights B1 and B2 of the protrusions 110, 210 and 310 are larger than the diameter of the cross section of the retaining ring 109, it is possible to more easily determine the misassembly.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiments. No.

1 ... Cylinder, 1b ... Caulking part, 1c ... Groove, 2 ... Piston, 3 ... Piston rod, 10A, 10B ... Shock absorber, 61 ... Extension side chamber, 62. ... Pressure side chamber, 109 ... Stop ring (positioning part), 110, 210, 310 ... Protruding part, 110i ... Radial inner edge, 130, 430 ... Oil seal unit (seal unit), 131,431 ... Seal housing (seal holding member), 132 ... Oil seal (seal member), 140,240 ... Bearing unit (support member), 141,241,341 ... Rod guide (bearing) Holding member), 142 ... Bush (bearing), 146 ... Communication path, 170 ... Rebound cushion, 441 ... Retainer (support member), 509 ... Support protrusion (positioning part)

Claims (8)

A cylinder filled with working fluid and
A piston that is slidably provided in the cylinder and divides the inside of the cylinder into an extension side chamber and a compression side chamber,
A piston rod that is freely inserted into the cylinder and connected to the piston,
A seal member having a seal member that slides on the outer periphery of the piston rod to prevent leakage of the working fluid and a seal holding member that holds the seal member, and a seal unit.
A support member that partitions the extension side chamber side and supports the seal unit, and
A positioning portion provided on the inner circumference of the cylinder and defining the axial position of the support member, and a positioning portion.
A caulking portion, which is formed at the end of the cylinder and secures the support member and the seal unit in a laminated state with the positioning portion, is provided.
The support member has a protrusion that protrudes toward the extension concubine on the center side of the position where the support member abuts on the position defining portion when the front and back surfaces of the support member are inserted into the cylinder in the first direction. ,
The rigidity of the seal holding member is higher than the rigidity of the seal member.
When the front and back surfaces of the support member are inserted into the cylinder in the first orientation, the surface opposite to the surface on which the protrusion is provided comes into contact with the seal holding member, and the support member A shock absorber characterized in that when the front and back surfaces are inserted into the cylinder in a second direction opposite to the first direction, the tip end portion of the protruding portion comes into contact with the seal holding member. In the shock absorber according to claim 1,
The support member is a shock absorber having a bearing in which the outer periphery of the piston rod is slidably contacted on the inner circumference and a bearing holding member for holding the bearing. In the shock absorber according to claim 1 or 2.
Further provided with an elastically deformable annular rebound cushion provided on the outer periphery of the piston rod and having a contact surface that contacts the support member when the shock absorber is fully extended.
The shock absorber is characterized in that the protruding portion comes into contact with the outer periphery of the rebound cushion when the shock absorber is fully extended. In the shock absorber according to claim 3,
The shock absorber is characterized in that the protruding portion is provided along the circumferential direction. In the shock absorber according to claim 4,
A shock absorber characterized in that the inner diameter of the base end portion of the protruding portion is larger than the outer diameter of the contact surface of the rebound cushion in a state where it is not elastically deformed. In the shock absorber according to claim 4 or 5.
The support member is provided with a communication passage that transmits the pressure of the extension side chamber to the seal member.
A shock absorber characterized in that a part of the opening on the extension side chamber side of the communication passage is arranged radially outside the radial inner edge of the protrusion. In the shock absorber according to claim 6,
The protrusions are arcuate and are provided in plurality along the circumferential direction.
A shock absorber characterized in that an opening on the extension side chamber side of the communication passage is arranged between adjacent protrusions. In the shock absorber according to any one of claims 1 to 7.
The positioning portion is an annular retaining ring provided separately from the cylinder and having a circular cross section.
An annular groove into which the retaining ring is fitted is provided on the inner peripheral surface of the cylinder.
A shock absorber characterized in that the axial length of the protrusion is larger than the diameter of the cross section of the retaining ring.

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