Abstract:
A monolever operating device that inclines in a two-dimensional manner including at least a front and rear direction and a right and left direction. A drive signal generating unit contained within a drive signal generating body for outputting two drive signals to components in the front and rear direction and in the right and left direction in accordance with an orientation and an amount of inclination of the monolever. The device further includes a universal joint mounted to support the monolever in an inclinable manner, a mount plate for mounting the drive signal generating body mounted thereto to a vehicle body, and a monolever bearing member provided on an upper surface of the mount plate and provided with lever bearing portions and boot holding portions alternately arranged adjacent to each other in a circumferential direction.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a monolever operating device, and more particularly, to a monolever operating device, which is excellent in abrasion resistance, good in durability and high in reliability and can be conformed to many kinds of machines.  
           [0003]    2. Description of the Related Art  
           [0004]    Inventions have been already known relating to an operating lever device, in which a single operating lever (referred below to as a “monolever”) is operatively inclined to generate an operating signal and two hydraulic actuators are drivingly controlled on the basis of the operating signal. For example, Japanese Patent Laid-Open No. 89515/1997 discloses an electrical type operating lever device, in which a monolever is operatively inclined to have each of four pistons issuing an electric signal representative of its displacement. Two hydraulic actuators can be drivingly controlled on the basis of an electric signal issued from the electrical type operating lever device.  
           [0005]    Also, Japanese Utility Model Publication No. 49167/1995 discloses a hydraulic type operating lever device  60  which outputs a hydraulic signal. In this publication, the hydraulic type operating lever device  60  comprises a hydraulic body  63  having four pistons  62 , which are pressed upon inclination of a monolever  61  in a front and rear direction and in a right and left direction, and of which respective displacements are output as hydraulic signals, on the basis of which two hydraulic actuators can be drivingly controlled.  
           [0006]    With the hydraulic body  63 , four pistons  62   a ,  62   b ,  62   c ,  62   d  (shown in FIG. 2), which constitute a piston  62 , are arranged in equidistant positions on a circumference in a manner to abut against a disk plate  64  mounted on the monolever  61 . The four pistons  62   a ,  62   b ,  62   c ,  62   d  are pushed and displaced by the disk plate  64  in accordance with an orientation and an amount of inclination of the monolever  61 .  
           [0007]    Hydraulic pressure generating means Hd for generating a hydraulic signal of a magnitude corresponding to respective displacements of the pistons  62   a ,  62   b ,  62   c ,  62   d  are provided on the hydraulic body  63 . In addition, the hydraulic body  63  comprises a drive signal generating body and the hydraulic pressure generating means Hd comprise a drive signal generating means.  
           [0008]    The monolever  61  is mounted to the hydraulic body  63  through a universal joint  65 . The hydraulic body  63  is mounted on a mount plate  66  shown in FIGS.  7 ( a ) and  7 ( b ) and on a vehicle body  68  near a driver seat by means of bolts  67  extending through vehicle body bolt holes  66   a  formed in the mount plate  66 .  
           [0009]    In FIGS.  7 ( a ) and  7 ( b ), the mount plate  66  is provided with a ring-shaped stopper projection  69 , which in turn is provided with arcuate-shaped projections  69   a  adapted to abut against the disk plate  64  to restrict an inclination θ of the monolever  61 . The mount plate  66  is provided with an annular groove  69   b  on an outer periphery of the ring-shaped stopper projection  69 . One end of a boot  70  covering the four pistons  62  is inserted into the annular groove  69   b . Also, the other end of the boot  70  is inserted into an annular groove  71   a  provided on an outer periphery of a coupling  71 , which connects the universal joint  65  and the monolever  61  to each other as shown in FIG. 6.  
           [0010]    In recent years, the operating lever device constituted in the above manner has been improved in operability and made small in size to be used in many construction machines and industrial machinery such as small-sized and large-sized hydraulic shovels, bulldozers, rough terrain cranes and so on.  
           [0011]    With the above constitution, Japanese Utility Model Publication No. 49167/1995 proposes the provision of a single mount plate for parts to improve an increase in cost, caused by an increased number of parts due to the fact that a part for mounting of a boot is separate from a mount plate.  
           [0012]    However, since the operating lever device has been used in many construction machines and industrial machinery in recent years as described above, the mount plate shown in FIGS.  7 ( a ) and  7 ( b ) differ in configuration and dimension of inclination every machine, and so manufacture of the single mount plate necessitates a new metallic mold to lead to an increase in cost of parts and a large amount of expense in manufacture of a metallic mold.  
           [0013]    For example, the mount plate is fabricated froma sintered material to shape the projection for stoppage and the arcuate projection in order to facilitate manufacture and realize cost reduction. There is caused a problem that a metallic mold for manufacture of the sintered material is increased in manufacture cost since an annular groove is provided on a side of the mount plate and manhour in assembling is increased at the time of manufacture.  
           [0014]    Also, since the mount plate is fabricated from a sintered material, the projection for stoppage and adapted to abut against the disk plate is worn. Such wear causes a problem that the operating lever device becomes hard to operate because an operating lever is increased in stroke after use over a long term.  
           [0015]    When the projection for stoppage is further increased in thickness in order to prevent the wear, there is caused a problem that the operating lever device becomes large and so difficult in use for small-sized construction machines or a major part of the device must be made large to impose a limitation on a driver seat. Also, a part for mounting of a boot and a mount plate are conventionally separate from each other, and so there is caused a problem that the boot is worsened in assembling property and cost is increased since the part does not function as a bearing portion for inclination of the operating lever and so other part is needed.  
         SUMMARY OF THE INVENTION  
         [0016]    The invention has been thought of in view of the above problems, relates to a monolever operating device and has its object to provide a monolever operating device, which is favorable in assembling property and susceptible of less wear and can be made small in size and inexpensively conformed to many kinds of machines.  
           [0017]    In order to attain the above objects, a monolever operating device according to the invention comprises a monolever capable of inclining in a two-dimensional optional direction conformed to at least a front and rear direction and a right and left direction, drive signal generating means received in a drive signal generating body to output two drive signals to components in the front and rear direction and in the right and left direction in accordance with an orientation and an amount of inclination of the monolever, a universal joint mounted on the drive signal generating body to support the monolever in an inclinable manner, a mount plate for mounting the drive signal generating body mounted thereto to a vehicle body, a boot provided between the monolever and the mount plate to cover the drive signal generating means, and a monolever bearing member provided on an upper surface of the mount plate and provided with lever bearing portions and boot holding portions alternately arranged adjacent to each other in a circumferential direction.  
           [0018]    In this case, the monolever bearing member comprises a press formed part of a low-carbon steel material subjected to carburization.  
           [0019]    Also, the monolever bearing member may comprise lever bearing portions provided perpendicular to a surface thereof being mounted on the mount plate and boot holding portions provided in parallel to the surface to hole the boot.  
           [0020]    Also, slits may be provided between the lever bearing portions and the boot holding portions of the monolever bearing member.  
           [0021]    Also, the lever bearing portions of the monolever bearing member may be formed to be arcuate Ra as viewed in plan view.  
           [0022]    With the above constitution, the monolever operating device comprises a mount plate for mounting the drive signal generating body to a vehicle body and a monolever stopping member for stopping an inclination of the monolever, and the arrangement is alternate on a circumference, whereby insertion of the boot into the monolever stopping member is facilitated and assembling is made easy to achieve reduction in manhour in assembling.  
           [0023]    Also, the monolever stopping member is made a single part whereby the monolever stopping member having a plurality of configurations can be subjected to drawing in one step to reduce cost for a metallic mold. Also, the monolever stopping member is made a single part whereby a monolever operating device capable of conforming to many kinds of machines can be provided by preparing a plurality of monolever stopping members having different sizes.  
           [0024]    The monolever bearing member is formed from a low-carbon steel material subjected to carburization to be increased in hardness, so that the lever bearing portions are reduced in wear, by which the performance can be prevented from changing after use over a long term. Also, fabrication is made by means of press work to thereby achieve reduction in manhour in work.  
           [0025]    The monolever bearing member is composed of the lever bearing portions and the boot holding portions, so that a demand for a design value with a different inclination can be accommodated for by modifying a length of a sheet material for the lever bearing portions. Also, even when a length of the lever bearing portions is modified at the time of press work, a metallic mold can be readily manufactured to reduce cost for manufacture of the mold and facilitate management of the mold.  
           [0026]    With the monolever bearing member, the slits are provided between the lever bearing portions and the boot holding portions of the monolever bearing member, whereby the lever bearing portions and the boot holding portions can be arranged alternately adjacent to each other in a circumferential direction, and press work can be performed with ease. At this time, the slits are extended inward from bent portions to thereby facilitate drawing.  
           [0027]    The lever bearing portions of the monolever bearing member are formed to be arcuate as viewed in plan view, so that the lever bearing portions are made high in allowable bending stress and so can be made thin to achieve miniaturization.  
           [0028]    As described above, the monolever bearing member is structured such that the lever bearing portions and the boot holding portions are arranged alternately adjacent to each other in a circumferential direction with the slits therebetween, a low-carbon steel material is subjected to carburization for an increased hardness, and the lever bearing portions are formed to be arcuate. Thereby, even when being made small in plate thickness, the monolever bearing member is enhanced in abrasion resistance and allowable bending stress, mounting of the boot is facilitated, the same metallic mold complies with a demand for a variety of inclinations, and press work is enabled, whereby work and assembling are facilitated, miniaturization is achieved, and a change in performance after use over a long term can be decreased.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    [0029]FIG. 1 is a side cross sectional view of a hydraulic monolever operating device according to an embodiment of the invention;  
         [0030]    [0030]FIG. 2 is a general plan view of the hydraulic monolever operating device according to the embodiment of the invention;  
         [0031]    [0031]FIG. 3 is a cross sectional view taken along the plane Y-Y in FIG. 1;  
         [0032]    FIGS.  4 ( a ) and  4 ( b ) are a part drawing of a monolever bearing member in the hydraulic monolever operating device according to the embodiment of the invention, A being a plan view, and B being a cross sectional view taken along the line A-Oa-A in A;  
         [0033]    FIGS.  5 ( a ) and  5 ( b ) are a part drawing of a mount plate in the hydraulic monolever operating device according to the embodiment of the invention, A being a plan view, and B being a cross sectional view taken along the line B-Oa-B in A;  
         [0034]    [0034]FIG. 6 is a side cross sectional view of a prior hydraulic monolever operating device; and  
         [0035]    FIGS.  7 ( a ) and  7 ( b ) are a part drawing of a mount plate in a prior hydraulic monolever operating device, A being a plan view, and B being a cross sectional view taken along the line C-Oa-C in A.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0036]    An embodiment of a monolever operating device according to the invention will be described below with reference to the drawings. In addition, the same reference numerals denote the same parts as those in the prior art.  
         [0037]    First, a monolever operating device according to the embodiment will be described with reference to FIGS.  1  to  5 ( b ). FIG. 1 is a side cross sectional view of a hydraulic monolever operating device  1  according to the embodiment, FIG. 2 being a general plan view of the device shown in FIG. 1, FIG. 3 being a cross sectional view taken along the plane Y-Y in FIG. 1, FIGS.  4 ( a ) and  4 ( b ) being a part drawing of a monolever bearing member, and FIGS.  5 ( a ) and  5 ( b ) being a part drawing of the monolever bearing member.  
         [0038]    In FIGS. 1 and 2, a hydraulic monolever operating device  1  is composed of a monolever section  3  capable of inclining in a front and rear direction, and in a right and left direction, and a hydraulic body  63  for outputting displacements of four pistons as a hydraulic signal every piston upon inclination of the monolever section  3 . The monolever section  3  extends through a universal joint hole  11   a  provided in a mount plate  11  for the hydraulic body  63  to be mounted to a valve body  63   a  of the hydraulic body  63 .  
         [0039]    Also, a disk plate  64  is mounted on the monolever section  3  as shown in FIG. 2 in a manner to abut against tip ends (upper ends) of four pistons  62   a ,  62   b ,  62   c ,  62   d  sealingly inserted into the hydraulic body  63 . The disk plate  64  is mounted to a lower end of a monolever  61  to push the pistons  62   a ,  62   b ,  62   c ,  62   d  in accordance with an orientation and an amount of inclination of the monolever  61  in the front and rear direction (for example, Y-axis direction) and the right and left direction (for example, X-axis direction).  
         [0040]    The pistons  62   a ,  62   b ,  62   c ,  62   d  are pushed by the disk plate  64  in accordance with an orientation and an amount of inclination of the monolever  61  of the monolever section  3  to undergo displacement, by which hydraulic pressure generating means Hd for generating a hydraulic signal of a magnitude corresponding to respective displacements of the pistons  62   a ,  62   b ,  62   c ,  62   d  are provided on the hydraulic body  63 . More specifically, the hydraulic pressure generating means Hd generate hydraulic signals of magnitudes corresponding to displacements, which the pistons  62   a ,  62   b ,  62   c ,  62   d  are pushed, in accordance with an orientation and an amount of inclination of the monolever  61  in the front and rear direction and in the right and left direction.  
         [0041]    In FIGS. 1 and 2, the monolever  61  of the monolever section  3  is connected to a universal joint  65  by a coupling  71  and supported by the universal joint  65  to be able to incline in the front and rear direction and in the right and left direction. The universal joint  65  extends through the universal joint hole  11   a  provided in the mount plate  11  to be mounted to the valve body  63   a  of the hydraulic body  63 .  
         [0042]    When the monolever  61  is turned (turned in an oblique direction) in the front and rear direction and in the right and left direction, the universal joint  65  causes the disk plate  64  to be inclined to push the respective pistons  62   a ,  62   b ,  62   c ,  62   d , whereupon hydraulic pressures conformed to components of displacements in the front and rear direction and in the right and left direction are output by the hydraulic pressure generating means Hd.  
         [0043]    In FIG. 1, the monolever section  3  comprises a monolever bearing member  17  adapted to abut against the disk plate  64  mounted to the monolever  61  to restrict a maximum inclination θm of the monolever  61 , a portion of the monolever bearing member  17  being disposed outside the four pistons  62   a ,  62   b ,  62   c ,  62   d . The monolever bearing member  17  is arranged on an upper surface of the mount plate  11  and mounted by means of bolts  19  to the valve body  63   a  of the hydraulic body  63  through the mount plate  11 .  
         [0044]    In FIGS.  4 ( a ) and  4 ( b ), formed in the monolever bearing member  17  are a universal joint hole  17   a  disposed centrally of the member and having the universal joint  65  extending therethrough, piston holes  17   b  disposed around the universal joint hole and having the pistons  62   a ,  62   b ,  62   c ,  62   d  extending therethrough, and bolt holes  17   d  disposed between the four piston holes  17   b , which have the pistons  62   a ,  62   b ,  62   c ,  62   d  extending therethrough, and having the bolts  19  extending therethrough.  
         [0045]    The monolever bearing member  17  comprises lever bearing portions  21  and boot holding portions  23 , which are alternately arranged on a circumference outside of the piston holes  17   b  and bolt holes  17   d . Provided on the monolever bearing member  17  are the lever bearing portions  21  provided perpendicular to a bottom surface  17   e  adapted to abut against the mount plate  11 , and the parallel boot holding portions  23  having a gap Sa for insertion of a boot thereinto and a surface parallel to the bottom surface  17   e.    
         [0046]    The lever bearing portions  21  are formed to be semi-circular in shape and provided so that peaks Pa of the semi-circular projections are positioned on respective lines La connecting a central point Oa and central points Ob of the four pistons  62   a ,  62   b ,  62   c ,  62   d , the peaks Pa abutting against the disk plate  64 .  
         [0047]    The monolever bearing member  17  comprises slits  25  between the lever bearing portions  21  and the boot holding portions  23 . The slits  25  are formed inward from an outer periphery of the monolever bearing member  17  to be cut inwardly of the lever bearing portions  21  and bent portions  24  of the boot holding portions  23 . Thereby, drawing by means of a press or the like is made easy.  
         [0048]    Also, the lever bearing portions  21  are formed to be arcuate Ra as viewed in plan view, and so enhanced in allowable bending stress and rigidity, which enables reducing a plate thickness.  
         [0049]    In the case where the monolever bearing members  17  are in large quantity, a sheet material is punched by means of press work and then the semi-produce is subjected to drawing by means of a metallic mold to be finished into a configuration shown in FIGS.  4 ( a ) and  4 ( b ). Also, in the case of small quantity or a special specification involving different inclinations (Hb relative to Ha), a sheet material is subjected to, for example, fine plasma work to be formed with an external shape, the universal joint hole  17   a , piston holes  17   b  and the bolt holes  17   d , and then subjected to drawing by means of the metallic mold as that described above.  
         [0050]    The boot holding portions  23  are pressed by an upper half of the metallic mold but the lever bearing portions  21  are not pressed from above, so that work can be readily made for an optional height of the bearing portions. Accordingly, a length of a sheet material for the lever bearing portions  21  is made a height for a maximum inclination corresponding to a design value of a desired maximum inclination and thereby drawing can be readily performed with the same metallic mold. Thus different heights Hb of the lever bearing portions  21  can be obtained with the same metallic mold, which reduces cost for metallic molds.  
         [0051]    After being formed into the configuration shown in FIGS.  4 ( a ) and  4 ( b ), the monolever bearing member  17  is subjected to heat treatment to be increased in hardness and enhanced in abrasion resistance. Thereby, even when the lever bearing portions  21  of the monolever bearing member  17  abut against the disk plate  64 , they undergo less wear.  
         [0052]    It is desired that the monolever bearing member  17  is composed of a formed part obtained by subjecting a low-carbon steel material to press work and then to carburization, which is inexpensive.  
         [0053]    As shown by way of example in FIGS.  5 ( a ) and  5 ( b ), the mount plate  11  is formed with an external shape conformed to a type of machine, and a pitch Ma of the holes for bolts, which are suited to and mounted to a vehicle body, is determined While the external shape and the pitch Ma of the bolt holes, respectively, are determined depending upon a vehicle or a type of machine, they can be readily conformed to a desired mount plate  11  because a sheet material is subjected to cutting work as it is.  
         [0054]    Formed in the mount plate  11  are the universal joint hole  11   a , piston holes  11   b  and bolt holes  11   d , which are disposed in the same positions as those of the universal joint hole  17   a , piston holes  17   b  and the bolt holes  17   d  formed in the monolever bearing member  17 . Also, the mount plate  11  is formed with holes  66   a  for bolts for a vehicle body mounted to the vehicle body  68 .  
         [0055]    The mount plate  11  is formed from an inexpensive sheet material such as common steel or low-carbon steel, and obtained by using press work to punch a sheet material in the case of large quantity. Also, in the case of small quantity, a sheet material is subjected to, for example, fine plasma work to be formed with an external shape, the universal joint hole  11   a , piston holes  11   b  and the bolt holes  11   d.    
         [0056]    The mount plate  11  is placed on an upper surface of the valve body  63   a  of the hydraulic body  63 , and then the monolever bearing member  17  is overlapped and laid on the mount plate and mounted to the valve body  63   a  of the hydraulic body  63  by means of bolts  19 . At this time, tip ends of the four pistons  62   a ,  62   b ,  62   c ,  62   d  project above the upper surfaces of the lever bearing portions  21  of the monolever bearing member  17 .  
         [0057]    Subsequently, the universal joint  65  is mounted on the valve body  63   a  of the hydraulic body  63 . The disk plate  64  is threaded onto the universal joint  65  while being adjusted in a manner to come into contact with tip ends of the four pistons  62   a ,  62   b ,  62   c ,  62   d . Further, the monolever  61  is connected to the universal joint  65  and the coupling  71 , to which a boot  70  is latched, is threaded onto the universal joint  65 .  
         [0058]    The boot  70  is placed on the hydraulic body  63  with a lower end thereof receiving therein the coupling  71  and the universal joint  65 . Subsequently, an entire surface of a lower portion of the boot  70  is pushed into the gap Sa after the lower portion is inserted from the boot holding portions  23  of the monolever bearing member  17 . At this time, the boot  70  is easily inserted into a first one of the boot holding portions  23  since the lever bearing portions  21  on both sides of the first one is provided in a withdrawn manner. When the boot  70  is inserted into the first one of the boot holding portions  23 , it can be easily inserted over the entire surface of the gap Sa by stretching the boot  70  with the first one as a support.  
         [0059]    Subsequently, an upper portion of the boot  70  is inserted into an annular groove  71   a  of the coupling  71  and thus assembling is terminated.  
         [0060]    Subsequently, an explanation will be given to operation of the above constitution. FIGS. 1 and 2 show a state, in which the monolever  61  is not inclined but centrally positioned in a neutral position Mn, in which any hydraulic pressure is not generated from the hydraulic pressure generating means Hd. Suppose, for example, that the monolever  61  is operated to be inclined to a maximum position Mm in the right and left direction as shown in FIG. 1. Accompanying this inclination, the disk plate  64  mounted on the monolever  61  is inclined to abut against the peak Pa of the semi-circular projection of the lever bearing portion  21  to be stopped, while pushing the piston  62   b.    
         [0061]    At this time, the lever bearing portion  21  is subjected to a bending force from the disk plate  64  but the lever bearing portions  21  are formed to be arcuate to be made high in allowable bending stress and so can be made thin as compared with the prior art. When the monolever  61  is turned at a maximum inclination θm, the piston  62   b  is pushed to the maximum and the hydraulic pressure generating means Hd generates a maximum hydraulic pressure corresponding to a maximum displacement.  
         [0062]    Whenever the monolever  61  is operated at the maximum inclination θm in the above manner, the disk plate  64  abuts against the peak Pa of the semi-circular projection of the lever bearing portion  21 . Since the monolever bearing member  17  is subjected to heat treatment to be increased in hardness and enhanced in abrasion resistance, it is susceptible of less wear, which eliminates a change in the maximum inclination even after use over a long term. Thereby, there is caused no change in maximum running speed, turning speed and the like, and operability experiences no change from the first to make operation easy in the same manner as at the time of shipping.  
         [0063]    While the above explanation has been given to the right and left direction, the same results can be obtained with respect to the front and rear direction. Also, while an explanation has been given to the above embodiment, in which the pistons  62   a ,  62   b ,  62   c ,  62   d  are arranged on perpendicular lines in the X-axis direction (for example, a right and left direction) and the Y-axis direction (for example, a front and rear direction), another embodiment may be adopted, in which the pistons  62   a ,  62   b ,  62   c ,  62   d  are arranged to be offset 45 degrees from the perpendicular lines in the X-axis direction and the Y-axis direction. Also, while an explanation has been given to the above embodiment by way of the hydraulic monolever operating device  1 , the above arrangement can be used in an electrical type operating lever device, in which a single operating lever is operatively inclined to have each of four pistons issuing an electric signal representative of its displacement, as in Japanese Patent Laid-Open No. 89515/1997.