Patent Publication Number: US-2005127587-A1

Title: Hydraulic shock absorbing apparatus of vehicle

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a hydraulic shock absorbing apparatus of a vehicle.  
      2. Description of the Related Art  
      For a hydraulic shock absorber of a vehicle, there is a structure in which a hydraulic shock absorber is provided in right and left sides of a wheel. As shown in Japanese Unexamined Utility Model Publication No. 64-41495, each of the shock absorbers has an expansion side damping force generating apparatus which is provided with two oil passages in a piston sliding within a cylinder. An expansion side damping valve generating an expansion side damping force in one oil passage is present, along with a compression side check valve easily opened at the time of compression and generating a slight compression side damping force in another oil passage. Each of the shock absorbers has a compression side damping force generating apparatus which is provided with two oil passages in a sub piston fixed to a bottom portion of the cylinder. A compression side damping valve generating a compression side damping force with respect to a working fluid in correspondence to a forward moving volume of a piston rod in one oil passage is present. An expansion check valve is also present and which is easily opened at the time of expansion and which generating a slight expansion side damping force in another oil passage.  
      In the conventional art, both of the hydraulic shock absorbers provided in both sides of the wheel have the expansion side damping force generating apparatus provided in the piston sliding within the cylinder, and the compression side damping force generating apparatus provided in the sub piston fixed to the bottom portion of the cylinder. Accordingly, the damping valve structure in each of the hydraulic shock absorbers is complex so as to increase the number of the parts, thereby making it difficult to reduce manufacturing cost.  
     SUMMARY OF THE INVENTION  
      An object of the present invention is to simplify a damping valve structure in each of hydraulic shock absorbers and to reduce manufacturing cost in a hydraulic shock absorbing apparatus provided with the hydraulic shock absorbers at right and left sides of a wheel.  
      The present invention relates to a hydraulic shock absorbing apparatus of a vehicle provided with hydraulic shock absorbers at right and left sides of a wheel. A compression side damping force generating means for mainly generating a compression side damping force is provided in one hydraulic shock absorber. An expansion side damping force generating means for mainly generating an expansion side damping force is provided in another hydraulic shock absorber. The generation of the compression side damping force and the expansion side damping force is shared by the right and left hydraulic shock absorbers. The one hydraulic shock absorber comprises a vehicle body side tube and a wheel side tube which are slidably fitted to each other. A damper constituted by a damper cylinder and a piston rod in which a piston sliding within the damper cylinder is mounted to a leading end portion thereof are present. These are structured such that the damper cylinder is mounted to an inner side of the wheel side tube and the piston rod is mounted to an inner side of the vehicle body side tube. A piston rod side oil chamber and a piston side oil chamber are sectioned within the damper cylinder by the piston. An oil reservoir chamber is provided in an outer periphery of the damper cylinder. Two oil passages are provided in the piston, in which a compression side damping valve is provided in the one oil passage, and a check valve closing at the time of compression and opening at the time of expansion is provided in the another oil passage. A volume compensating oil passage of the piston rod communicating the piston rod side oil chamber with the oil reservoir chamber is provided.  
      The present invention relates to a hydraulic shock absorbing apparatus of a vehicle having hydraulic shock absorbers provided at both right and left sides of a wheel. Each of the hydraulic shock absorbers are structured such that a vehicle body side tube and a wheel side tube are slidably fitted. A damper is constituted by a damper cylinder and a piston rod having a piston sliding within the damper cylinder. The piston is mounted to a leading end portion thereof The damper cylinder is mounted to an inner side of the wheel side tube, and the piston rod is mounted to an inner side of the vehicle body side tube. A piston rod side oil chamber receiving the piston rod and a piston side oil chamber not receiving the piston rod are sectioned in both sides of the piston. Two oil passages communicating the two oil chambers are provided in the piston. An oil reservoir chamber for compensating a volume of the piston rod is provided in an outer periphery of the damper cylinder. One of the hydraulic shock absorbers is provided with a compression side damping valve in one oil passage of the piston, and a check valve which closes during compression and opens during expansion in another oil passage. An oil passage for compensating a volume of the piston rod communicated with the oil reservoir chamber is provided in the piston rod side oil chamber. Another of the hydraulic shock absorbers is provided with an expansion side damping valve in one oil passage of the piston, and is provided with a check valve which closes during expansion and which opens during compression in another oil passage. An oil passage for compensating the volume of the piston rod communicated with the oil reservoir chamber is provided in the piston side oil chamber. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention will be more fully understood from the detailed description given below and from the accompanying drawings which should not be taken to be a limitation on the invention, but are for explanation and understanding only.  
      The drawings:  
       FIG. 1  is a general view showing one of right and left hydraulic shock absorbers;  
       FIG. 2  is an enlarged view of a main portion in  FIG. 1 ;  
       FIGS. 3A and 3B  show a modified embodiment in which an oil passage is provided in a rod guide, in which  FIG. 3A  is a cross sectional view and  FIG. 3B  is a plan view of a bush;  
       FIG. 4  is a general view showing the other of the right and left hydraulic shock absorbers (the other of  FIG. 1 ); and  
       FIG. 5  is an enlarged view of a main portion in  FIG. 4 .  
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      A hydraulic shock absorbing apparatus  1  of a vehicle is constituted by left and right shock absorbers  100  and  200  provided at both left and right sides of the vehicle. The hydraulic shock absorbing apparatus  1  is structured such that wheel side tubes of the left and right hydraulic shock absorbers are mounted to both sides of a common axle as in a front fork of a two-wheeled vehicle or the like. The left and right hydraulic shock absorbers may be mounted to a common swing arm as in a rear side hydraulic shock absorbing apparatus of a two-wheeled vehicle or the like, except in an independent suspending type hydraulic shock absorbing apparatus.  
      One of the left and right hydraulic shock absorbers  100  is structured as shown in FIGS.  1  to  3 , and the other of the left and right hydraulic shock absorbers  200  is structured as shown in  FIG. 4  and  FIG. 5 . The hydraulic shock absorbing apparatus  1  is provided with a compression side damping force generating means  101  mainly generating a compression side damping force in one hydraulic shock absorber  100 , and is provided with an expansion side damping force generating means  201  mainly generating an expansion side damping force in another hydraulic shock absorber  200 . The generation of the compression side damping force and the expansion side damping force is shared by the left and right hydraulic shock absorbers  100  and  200 .  
     Hydraulic Shock Absorber  100 ,—FIGS.  1  to  3   
      The hydraulic shock absorber  100  is structured, as shown in  FIG. 1 , such that a vehicle body side tube  11  and a wheel side tube  12  are slidably fitted to each other in a liquid-tight manner. A bush  13  is provided in an outer periphery in a lower end side of the vehicle body side tube  11 , and a bush  14  is provided in an inner periphery in an upper end side of the wheel side tube  12 . An oil hole  11 A communicating an oil reservoir chamber  28  mentioned below with an annular gap clamped by the bushes  13  and  14  between the vehicle body side tube  11  and the wheel side tube  12  is provided in a lower end side of the vehicle body side tube  11 .  
      The vehicle body side tube  11  has a cap  16  detachably arranged in an opening portion  15  of the upper end portion in a liquid-tight manner, and is provided with a vehicle body side mounting portion in the vehicle body side tube  11 . The wheel side tube  12  is integrally provided with a bottom bracket  18  in the lower end portion, and is provided with an axle side mounting portion  19  in a bottom bracket  18 .  
      The hydraulic shock absorber  100  receives a damper cylinder  21  and a piston rod  24  constituting a damper  20  in inner portions of the vehicle body side tube  11  and the wheel side tube  12 . The hydraulic shock absorber  100  is provided with the damper cylinder  21  fixed to the inner portion of the bottom bracket  18  in the inner portion of the wheel side tube  12  in a rising manner. A stopper ring  22 A engaged with an inner periphery of a lower end of the damper cylinder  21  is pulled by a center bolt  22  inserted and attached to a bottom portion of the bottom bracket  18 . The damper cylinder  21  is fixed to the bottom portion of the bottom bracket  18  under interposition of a flange  37 A of an oil lock piece  37  mentioned below. The front fork  10  is structured such that a spring load adjusting sleeve  23  is screwed in a liquid-tight manner with a center portion of the cap  16 . A hollow piston rod  24  and a lock nut  23 A are screwed with a lower end portion of the spring load adjusting sleeve  23  inserted to the inner portion of the vehicle body side tube  11 . The piston rod  24  is fixedly supported to the vehicle body side tube  11 . The piston rod  24  slidably passes through a rod guide  25  provided in an upper end portion of the damper cylinder  21  so as to be inserted to an oil chamber  27  in the inner portion of the damper cylinder  21 , and is provided with a piston  26  in a piston bolt  24 A arranged in an insertion leading end portion thereof. The piston  26  is fixed by a nut  24 B screwed with the piston bolt  24 A. The piston  26  vertically slides along an inner surface of the damper cylinder  21 . The oil chamber  27  is sectioned into a piston rod side oil chamber  27 A in a side to which the piston rod  24  is inserted, and a piston side oil chamber  27 B in a side to which the piston rod  24  is not inserted, by the piston  26 .  
      The rod guide  25  is provided with an inner collar  25 E to which an O-ring  25 D is fitted and attached, in upper and lower washers  25 A and  25 B fixed to the upper end portion of the damper cylinder  21  in accordance with a caulking operation, and an inner portion of an outer collar  25 C, and which slidably supports the piston rod  24  by a bush  25 F pressure inserted to the inner collar  25 E. The O-ring  25 D absorbs an axial displacement between the damper cylinder  21  and the piston rod  24 . The inner collar  25 E and the bush  25 F may vertically move between the upper and lower washers  25 A and  25 B, or may be fixed so as to be immobile vertically.  
      The hydraulic shock absorber  100  is structured such that a space in an outer periphery of the damper cylinder  21  is formed as the oil reservoir chamber  28  between the vehicle body side tube  11  and the wheel side tube  12 . A gas chamber, such as an air chamber,  29  is formed in an upper portion of the oil reservoir chamber  28 .  
      The hydraulic shock absorber  100  has a spring collar  31  constituted by a connection of a plurality of members which ascend and descend where being supported by the spring load adjusting sleeve  23  mentioned above provided in the cap  16 . It is structured such that a suspension spring  34  is interposed between an upper spring seat  32  backed up by the spring collar  31 , and a lower spring seat  33  fixed to an outer periphery of the upper end portion of the damper cylinder  21 .  
      The hydraulic shock absorber  100  buffers an impact force applied from a road surface when the vehicle travels by a spring reaction force of the suspension spring  34 , and a spring reaction force applied by the gas spring in the air chamber  29 .  
      The hydraulic shock absorber  100  has the compression side damping force generating means  101  mentioned above in order to damp an expansion and contraction vibration of the suspension spring  34  and the gas spring in the gas chamber  29 .  
      The compression side damping force generating means  101  has a compression side oil passage  41  and an expansion side flow passage  42  allowing the piston rod side oil chamber  27 A and the piston side oil chamber  27 B to be communicated. The piston  26 , sidably in contact with the inner surface of the damper cylinder  21 , as shown in  FIG. 2 , can open and close the compression side oil passage  41  by the compression side damping valve  43 , and can open and close the expansion side flow passage  42  by the check valve  44 . The compression side damping valve  43  is supported in a backup manner by a valve stopper  43 A engaged by the piston rod  24 . The check valve  44  is supported in a backup manner by a valve spring  44 B held by a spring receiver  44 A fixed by the nut  24 B, which is closed at the time of compression and is opened at the time of expansion.  
      The compression side damping force generating means  101  has a bypass passage  46  which can communicate the piston rod side oil chamber  27 A with the piston side oil chamber  27 B while bypassing the piston  26  in an inner portion of the piston rod  24 , the piston bolt  24 A, and can open and close the bypass flow passage  46  by a needle valve  47 A. At this time, a damping force adjusting rod  47  is screwed with a center of the spring load adjusting sleeve  23  provided in the cap  16 . The damping force adjusting rod  47  is inserted to the hollow portion of the piston rod  24 , and the needle valve  47 A mentioned above is provided in an insertion end thereof.  
      The needle valve  47 A provided in the compression side damping force generating means  101  of the hydraulic shock absorber  100  serves as a compression side damping force adjusting apparatus.  
      The compression side damping force generating means  101  is provided with a volume compensating hole-shaped oil passage  50  of the piston rod  24  in a side wall of the upper end side of the damper cylinder  21 . The oil passage  50  communicates the piston rod side oil chamber  27 A with the oil reservoir chamber  28 .  
      Accordingly, the hydraulic shock absorber  100  is operated in the following manner.  
     Compression Stroke  
      At the time of compression of the hydraulic shock absorber  100 , the vehicle body side tube  11  and the wheel side tube  12  are compressed relatively, and the suspension spring  34  is compressed. The piston rod  24  moves forward into the damper cylinder  21 , the oil in the piston side oil chamber  27 B flows to the piston rod side oil chamber  27 A through the bypass oil passage  46  of the piston  26  at the time of low speed, and the compression side damping force is obtained on the basis of a throttle resistance of the needle valve  47 A during this time. During middle and high speed, the oil in the piston side oil chamber  27 B flows to the piston rod side oil chamber  27 A through the compression side damping valve  43  in the compression side oil passage  41  of the piston  26 . The compression side damping force is obtained on the basis of a deflection resistance of the compression side damping valve  43  during this time. The spring force of the suspension spring  34  buffers the impact at the time of compression, and the compression side damping force controls a compression speed of the suspension spring  34 .  
      In this case, during the greatest compression of the hydraulic shock absorber  100 , the check valve  36 A of the oil lock collar  36  provided in the lower end portion of the vehicle body side tube  11  is fitted to an outer periphery of the oil lock piece  37  provided in a rising manner in the bottom portion of the wheel side tube  12 . The oil lock oil chamber is sectioned between the wheel side tube  12  and the oil lock piece  37 , and a maximum compression stroke is controlled.  
      During compression of the hydraulic shock absorber  100 , the oil in an amount corresponding to the forward moving volume of the piston rod  24  to the damper cylinder  21  is discharged from the piston rod side oil chamber  27 A to the oil reservoir chamber  28  through the oil passage  50  of the damper cylinder  21 .  
     Expansion Stroke  
      During expansion of the hydraulic shock absorber  100 , the vehicle body side tube  11  and the wheel side tube  12  are expanded relatively, and the suspension spring  34  is expanded. The piston rod  24  moves backward from the damper cylinder  21 , The oil in the piston rod side oil chamber  27 A flows to the piston side oil chamber  27 B while pushing open the check valve  44  in the expansion side oil passage  42  of the piston  26 .  
      In this case, at the time of greatest expansion of the hydraulic shock absorber  100 , a rebound spring  39  supported in a backup manner by a spring receiver  38  engaged with the outer peripheral portion in the upper end side of the damper cylinder  21  is compressed by the upper end washer of the oil lock collar  36 , and a maximum expansion stroke is controlled.  
      During expansion of the hydraulic shock absorber  100 , the oil in an amount corresponding to the backward moving volume of the piston rod  24  from the damper cylinder  21  is resupplied to the piston rod side oil chamber  27 A from the oil reservoir chamber  28  through the oil passage  50  of the damper cylinder  21 .  
      In the hydraulic shock absorber  100 , the oil passage  50  provided for compensating the volume of the piston rod  24  may be formed in a rod guide  51 , corresponding to the rod guide  25  mentioned above, provided in the upper end portion of the damper cylinder  21  for guiding the piston rod  24 , as shown in  FIG. 3 . The rod guide  51  receives a bush  51 D in an inner portion of upper and lower washers  51 A and  51 B fixed to the upper end portion of the damper cylinder  21  in accordance with a caulking operation, and an outer collar  51 C via an annular gap. It is provided with oil grooves  51 E and  51 F extending around an entire length of the bush  51 D in a radial direction, in a plurality of positions of upper and lower end surfaces of the bush  51 D in a peripheral direction. The bush  51 D may vertically move between the upper and lower washers  51 A and  51 B, or may be fixed so as to be immobile vertically. The oil passage  50  is formed by a gap formed by inner peripheries of the upper end lower washers  51 A and  51 B with respect to an outer periphery of the piston rod  24 , the upper and lower oil grooves  51 E and  51 F, and an annular gap between the outer collar  51 C and the bush  51 D.  
     Hydraulic Shock Absorber  200 ,—FIGS.  4  and  5   
      The hydraulic shock absorber  200  is different from the hydraulic shock absorber  100  mainly in that the compression side damping force generating means  101  in the hydraulic shock absorber  100  is replaced by an expansion side damping force generating means  201 , as shown in  FIG. 4 .  
      The hydraulic shock absorber  200  has the expansion side damping force generating means  201  mentioned above, in order to damp the expansion and contraction vibration of the suspension spring  34  and the air spring in the air chamber  29 .  
      In the expansion side damping force generating means  201 , the piston  26  provided in the piston bolt  24 A of the piston rod  24  is reverted to that in the compression side damping force generating means  101  of the hydraulic shock absorber  101 , as shown in  FIG. 5 . The expansion side damping force generating means  201  has an expansion side oil passage  61  and a compression side oil passage  62  allowing the piston rod side oil chamber  27 A and the piston side oil chamber  27 B to be communicated. The piston  26  which is slidably in contact with the inner surface of the damper cylinder  21 , can open and close the expansion side oil passage  61  by an expansion side damping valve  63 , and can open and close the compression side oil passage  62  by a check valve  64 . The expansion side damping valve  63  is supported in a backup manner by a valve stopper  63 A fixed by the nut  24 B. The check valve  64  which is supported in a backup manner by a valve spring  64 B held by a spring receiver  64 A engaged by the piston rod  24 , is closed during expansion and is opened during compression.  
      The expansion side damping force generating means  201  has a bypass oil passage  46  which can communicate the piston rod side oil chamber  27 A with the piston side oil chamber  27 B while bypassing the piston  26 , in the inner portion of the piston rod  24 , the piston bolt  24 A, in the same manner as that of the compression side damping force generating means  101 . The bypass oil passage  46  can be opened and closed by the needle valve  47 A. At this time, the damping force adjusting rod  47  is screwed with the center of the spring load adjusting sleeve  23  provided in the cap  16 . The damping force adjusting rod  47  is inserted into the hollow portion of the piston rod  24 , and the needle valve  47 A mentioned above is provided in the insertion end thereof.  
      The needle valve  47 A provided in the expansion side damping force generating means  201  of the hydraulic shock absorber  200  serves as an expansion side damping force adjusting apparatus.  
      The expansion side damping force generating means  201  is provided with a volume compensating hole-shaped oil passage  70  of the piston rod  24  in the side wall of the lower end side of the damper cylinder  21 . The oil passage  70  communicates the piston side oil chamber  27 B with the oil reservoir chamber  28 .  
      The hydraulic shock absorber  200  is operated in the following manner.  
     Compression Stroke  
      During compression of the hydraulic shock absorber  200 , the vehicle body side tube  11  and the wheel side tube  12  are compressed relatively, and the suspension spring  34  is compressed. The piston rod  24  moves forward into the damper cylinder  21 , and the oil in the piston side oil chamber  27 B flows to the piston rod side oil chamber  27 A while pushing open the check valve  64  in the compression side oil passage  62  of the piston  26 .  
      At the time of maximum compression of the hydraulic shock absorber  200 , the check valve  36 A of the oil lock collar  36  provided in the lower end portion of the vehicle body side tube  11  is fitted to an outer periphery of the oil lock piece  37  provided in a rising manner in the bottom portion of the wheel side tube  12 . The oil lock oil chamber is sectioned between the wheel side tube  12  and the oil lock piece  37 , and the maximum compression stroke is controlled.  
      During compression of the hydraulic shock absorber  200 , oil in an amount corresponding to the forward moving volume of the piston rod  24  to the damper cylinder  21  is discharged from the piston rod side oil chamber  27 B to the oil reservoir chamber  28  through the oil passage  70  of the damper cylinder  21 .  
     Expansion Stroke  
      During expansion of the hydraulic shock absorber  200 , the vehicle body side tube  11  and the wheel side tube  12  are expanded relatively, and the suspension spring  34  is expanded. The piston rod  24  moves backward from the damper cylinder  21 . The oil in the piston rod side oil chamber  27 A flows to the piston side oil chamber  27 B through the bypass oil passage  46  of the piston  26  during low speed movement, and the expansion side damping force is obtained on the basis of a throttle resistance of the needle valve  47 A during this time. During middle and high speed movement, the oil in the piston rod side oil chamber  27 A flows to the piston side oil chamber  27 B through the expansion side damping valve  63  in the expansion side oil passage  61  of the piston  26 , and the expansion side damping force is obtained on the basis of a deflection resistance of the expansion side damping valve  63  during this time. The expansion side damping force prevents the suspension spring  34  from resonating.  
      In this case, at the time of maximum expansion of the hydraulic shock absorber  200 , a rebound spring  39  supported in a backup manner by a spring receiver  38  engaged with the outer peripheral portion in the upper end side of the damper cylinder  21  is compressed by the upper end washer of the oil lock collar  36 , and a maximum expansion stroke is controlled.  
      During expansion of the hydraulic shock absorber  200 , oil in an amount corresponding to the backward moving volume of the piston rod  24  from the damper cylinder  21  is resupplied to the piston side oil chamber  27 A from the oil reservoir chamber  28  through the oil passage  70  of the damper cylinder  21 .  
      In the hydraulic shock absorbing apparatus  1 , the expansion and compression vibration of the suspension spring  34  is dampened by the compression side damping force generated by the compression side damping force generating means  101  of the hydraulic shock absorber  100  in the compression stroke, and by the expansion side damping force generated by the expansion side damping force generating means  201  of the hydraulic shock absorber  200  in the expansion stroke.  
      In accordance with the present embodiment, the following effects can be obtained.  
      (1) The hydraulic shock absorber  100  in the side generating the compression side damping force generates the compression side damping force by the compression side damping valve  43  provided in the piston  26  sliding within the damper cylinder  21 . Accordingly, it is not necessary that the hydraulic shock absorber  100  in the side generating the compression side damping force has the compression side damping force generating apparatus in which the compression side damping valve and the expansion side check valve are provided in the sub piston fixed to the bottom portion of the damper cylinder  21 . In this manner, it is possible to reduce the manufacturing cost.  
      (2) In the hydraulic shock absorber  100 , the volume compensating oil passage  50  of the piston rod  24  which communicates the piston rod side oil chamber  27 A in the inner portion of the damper cylinder  21  with the oil reservoir chamber  28  in the outer side of the damper cylinder  21 . Accordingly, during compression, substantially all of the working fluid in the piston side oil chamber  27 B reaches the piston rod side oil chamber  27 A through the compression side damping valve  43 , and further flows to the oil reservoir chamber  28  in the outer side of the damper cylinder  21  via the oil passage  50 .  
      Accordingly, in comparison with the case that the volume compensating oil passage  50  is provided in the side of the piston side oil chamber  27 B, substantially all of the working fluid passes through the compression side damping valve  43 , so that it is possible to generate a stable compression side damping force.  
      In the case that the volume compensating oil passage  50  is provided in the side of the piston side oil chamber  27 B, the compression side damping valve  43  of the piston  26  and the oil passage  50  in the side of the piston side oil chamber  27 B form parallel flow passages with each other. It is difficult to set the size of the oil passage  50  in the side of the piston side oil chamber  27 B, and the compression side damping force is not stably generated.  
      (3) It is not necessary that the hydraulic shock absorber  200  in the side generating the expansion side damping force has the compression side damping force generating apparatus in which the compression side damping valve and the expansion side check valve are provided in the sub piston fixed to the bottom portion of the damper cylinder  21 . It is thereby possible to reduce the manufacturing cost.  
      (4) The damping force adjusting valve (the needle valve  47 A) provided in the hydraulic shock absorber  100  in the side generating the compression side damping force serves as the compression side damping force adjusting apparatus. The damping force adjusting valve (the needle valve  47 A) provided in the hydraulic shock absorber  200  in the side generating the expansion side damping force serves as the expansion side damping force adjusting apparatus. Accordingly, it is possible to independently adjust the damping force in each of the hydraulic shock absorbers  100  and  200 .  
      In the conventional art, since both of the left and right hydraulic shock absorbers  100  and  200  are provided with both of the expansion side damping force adjusting apparatus and the compression side damping force adjusting apparatus, it is necessary to adjust the left and right compression side damping force adjusting apparatuses during adjustment of the compression side damping force. It is also necessary to adjust the left and right compression side damping force adjusting apparatuses in an equal amount. Further, it is necessary to adjust the left and right expansion side damping force adjusting apparatuses during adjustment of the expansion side damping force.  
      It is necessary to adjust the left and right expansion side damping force adjusting apparatuses in an equal amount.  
      (5) Since the oil passage  50  is formed on the side wall of the damper cylinder  21 , the structure can be made simple, and the cost can be reduced.  
      (6) Since the oil passage  50  is provided in the guide member, the rod guide  51 , of the piston rod  24 , it is possible to improve dimensional accuracy of the size of the oil passage  50 .  
      As mentioned above, in accordance with the present invention, in the hydraulic shock absorbing apparatus in which hydraulic shock absorbers are provided at the left and right sides of the wheel, it is possible to make the damping valve structure in each of the hydraulic shock absorbers simple, thereby reducing the manufacturing cost.  
      As heretofore explained, embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configurations of the present invention are not limited to the illustrated embodiments but those having a modification of the design within the range of the present claimed invention are also included in the present invention.  
      Although the invention has been illustrated and described with respect to several exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made to the present invention without departing from the spirit and scope thereof. Therefore, the present invention should not be understood as limited to the specific embodiment set out above, but should be understood to include all possible embodiments which can be encompassed within a scope of equivalents thereof with respect to the features set out in the appended claims.