JP5879296B2 - Electric traveling vehicle - Google Patents

Description

  The present invention relates to an electric traveling vehicle including a parking brake device.

  For example, a construction machine represented by an articulated wheel loader or the like is provided with a parking brake device to prevent unintentional movement during parking. In a working vehicle (traveling vehicle) that uses an internal combustion engine as a power source, for example, a forward brake and a reverse clutch provided in a transmission are simultaneously engaged to fix a transmission brake so that a parking brake is fixed. Operate.

  However, in an electric traveling vehicle, for example, a series hybrid type wheel loader, the forward and backward movements can be switched under the control of the traveling electric motor, and therefore no transmission is provided. Therefore, for example, a series hybrid type wheel loader does not have a forward clutch and a reverse clutch, and cannot provide a parking brake that uses a transmission such as a traveling vehicle that uses an internal combustion engine as a power source. Therefore, for example, in a series hybrid type wheel loader, a parking brake must be provided separately.

  As a parking brake device for a traveling vehicle, for example, an electric parking brake device is known. In this electric parking brake device, the parking brake is actuated and released by rotating the electric motor (see Patent Document 1).

JP-T-2005-513366

  However, when the electric parking brake device described in the above-mentioned patent document is adopted for an electric traveling vehicle, the parking brake can be released if a malfunction occurs in the electric system for rotationally driving the electric motor of the parking brake. There is a risk of disappearing.

(1) An electric traveling vehicle according to the invention of claim 1 is an articulated electric traveling vehicle in which a front vehicle body and a rear vehicle body are bent left and right with a connecting shaft as a rotation axis, the rotor, A driving motor that has a stator and a rotor and a housing that holds the stator inside, and that gives a driving force; and a disc-type hydraulic negative brake that applies a parking brake command to the brake disc by a parking brake command; A parking brake device that releases a parking brake force by a brake release pressure by hydraulic pressure, and a brake release device that has a pressure accumulator and supplies the brake release pressure to the parking brake device by pressure oil held by the pressure accumulator. The device consists of a brake disc, a brake pad, and a brake carrier that presses the brake pad against the brake disc. The traveling motor has a motor side mounting portion to which the brake caliper is mounted on the housing, the brake caliper is mounted on the motor side mounting portion, and the traveling motor is provided on the front vehicle body. 1, and a second traveling motor provided on the rear vehicle body. The housing of the second traveling motor has a larger outer diameter than the housing of the first traveling motor, and is mounted on the motor side. The portion is provided on an end surface on the front side of the housing of the second traveling electric motor .
(2) An electric traveling vehicle according to the invention of claim 2 is an articulated electric traveling vehicle in which a front vehicle body and a rear vehicle body are bent left and right around a connecting shaft as a rotation axis, the rotor, A driving motor that has a stator and a rotor and a housing that holds the stator inside, and that gives a driving force; and a disc-type hydraulic negative brake that applies a parking brake command to the brake disc by a parking brake command; A parking brake device that releases a parking brake force by a brake release pressure by hydraulic pressure, and a brake release device that has a pressure accumulator and supplies the brake release pressure to the parking brake device by pressure oil held by the pressure accumulator. The device consists of a brake disc, a brake pad, and a brake carrier that presses the brake pad against the brake disc. The traveling motor has a motor side mounting portion to which the brake caliper is mounted on the housing, the brake caliper is mounted on the motor side mounting portion, and the traveling motor is provided on the front vehicle body. 1 and a second traveling motor provided on the rear vehicle body. The first traveling motor housing has a larger outer diameter than the second traveling motor housing, and is mounted on the motor side. The portion is provided on an end face on the rear side of the housing of the first traveling electric motor.
( 3 ) The invention according to claim 3 is the electric traveling vehicle according to claim 1 or 2 , wherein the parking brake device is configured such that the front vehicle body and the rear vehicle body have either a left or right connection shaft as a rotation axis. When it is bent in the direction, it is exposed to the space in either the left or right direction of the connecting shaft.
( 4 ) The invention of claim 4 is the electric traveling vehicle according to any one of claims 1 to 3 , further comprising a pedestal attached to the motor side mounting portion, and the brake caliper is attached to the motor side mounting portion. It is attached to the electric motor side attaching part via the attached base.

  According to the present invention, a parking brake device that gives a parking brake force to a brake disc by a parking brake command and releases a parking brake force by a brake release pressure by hydraulic pressure, and a pressure oil that has a pressure accumulator and is held by the pressure accumulator. And a brake release device that supplies brake release pressure to the parking brake device. As a result, it is possible to prevent a problem that the movement or operation of the electric traveling vehicle cannot be performed because the parking brake cannot be released, which contributes to the improvement of work efficiency.

1 is a side view of a series hybrid wheel loader that is an example of an electric traveling vehicle according to the present invention. FIG. It is a figure which shows an example of a structure of a wheel loader. It is a figure which shows a motor request torque map (motor characteristic). It is a functional block diagram for demonstrating the determination method of the torque of a rear motor and a front motor. FIG. 5A is a schematic sectional view showing a front motor, and FIG. 5B is a schematic sectional view showing a rear motor. It is the figure which showed simply the rear motor and front motor which were mounted in the wheel loader. It is a top view of a wheel loader. It is a principal part enlarged plan view of a front motor and a rear motor. It is a figure which shows an example of the cross-sectional structure of a parking brake apparatus, and the attachment state of a parking brake apparatus. It is an exploded view of a rear motor and a parking brake device. It is a perspective view when the front part vehicle body and the rear part vehicle body bent the right side with the connection axis | shaft when the connection axis vicinity of the wheel loader was seen from the left front. It is a figure when the attachment state of a parking brake apparatus is seen from the front of a parking brake. It is a figure when the attachment state of a parking brake apparatus is seen from the upper direction of a parking brake. It is the hydraulic circuit diagram which showed the part which mainly concerns on this Embodiment among the hydraulic circuits of a wheel loader. It is a figure which shows a modification.

  An embodiment of an electric traveling vehicle according to the present invention will be described with reference to FIGS. In the present embodiment, the case where the present invention is applied to a series hybrid wheel loader will be described.

  FIG. 1 is a side view of a series hybrid type wheel loader 100 which is an example of an electric traveling vehicle according to the present invention. The wheel loader 100 includes a front vehicle body 110 having an arm 111, a bucket 112, a front wheel 113, and the like, and a rear vehicle body 120 having an operator cab 121, an engine compartment 140, a rear wheel 123, and the like.

  The wheel loader 100 according to the present embodiment is an articulated wheel loader 100 in which a front vehicle body 110 and a rear vehicle body 120 are bent left and right with connecting shafts 101U and 101L as bending axes. The front vehicle body 110 and the rear vehicle body 120 are rotatably connected to each other by connecting shafts 101U and 101L, and the front vehicle body 110 is refracted left and right with respect to the rear vehicle body 120 by the expansion and contraction of the steering cylinder 116.

  An arm 111 is connected to the front vehicle body 110 so as to be rotatable in the vertical direction, and the arm 111 is rotated in the vertical direction (up and down movement) by driving of the arm cylinder 117. A bucket 112 is connected to the tip of the arm 111 so as to be rotatable in the vertical direction. The bucket 112 is rotated (cloud or dumped) in the vertical direction by driving the bucket cylinder 115.

  FIG. 2 is a diagram illustrating an example of the configuration of the wheel loader 100. The wheel loader 100 includes a main controller 20, an engine 1, an engine controller 21, a traveling electric device 100E, a working hydraulic device (hereinafter simply referred to as a working device) 100H, and a traveling drive device 100D.

  The working device 100H includes an arm 111 and a bucket 112 (see FIG. 1), an arm cylinder 117 and a bucket cylinder 115, and is driven by pressure oil discharged from a working hydraulic pump 10 driven by the engine 1. Is done. Pressure oil discharged from the working hydraulic pump 10 is supplied to the arm cylinder 117 and the bucket cylinder 115 via the control valve 11. By operating the arm operation lever 57 and the bucket operation lever 58 in the cab 121, the control valve 11 operates, the hydraulic oil is appropriately distributed to the arm cylinder 117 and the bucket cylinder 115, and a predetermined amount is supplied to the arm 111 and the bucket 112. The operation can be performed.

  The traveling electric device 100E includes a motor / generator 5, an M / G inverter 25, a front motor 3 and a rear motor 4, which are traveling electric motors, a front inverter 23, a rear inverter 24, and a storage element (for example, a capacitor) 7 And a converter 27.

  The travel drive device 100D includes axles 60F and 60R, differential devices 70F and 70R, and a propeller shaft 64, and is driven by the front motor 3 and the rear motor 4.

  A connection structure between the front motor 3 and the rear motor 4 will be described with reference to FIGS. 2, 6, and 7. A motor shaft 63 is integrated with the rotor 3 r of the front motor 3, and a motor shaft 65 is integrated with the rotor 4 r of the rear motor 4. The vehicle rear end of the front motor shaft 63 and the vehicle front end of the rear motor shaft 65 are connected to the propeller shaft 64 via universal joints 73 and 74. That is, the motor shaft 65 of the rear motor 4 is connected to the rear end of the propeller shaft 64 via the first universal joint 74, and the motor of the front motor 3 is connected to the front end of the propeller shaft 64 via the second universal joint 73. A shaft 63 is connected. Thereby, the motor shaft 63 of the front motor 3 and the motor shaft 65 of the rear motor 4 are connected by the propeller shaft 64 and the pair of universal joints 73 and 74 and rotate integrally.

  The pair of front wheels 113 are respectively connected to the front wheel side axle 60F. The front wheel side axle 60F is connected to a differential device 70F, and the differential device 70F is connected to the motor shaft 63 of the front motor 3 via a connecting portion 72 formed of a pair of universal joints. Each of the pair of rear wheels 123 is connected to the rear wheel side axle 60R. The rear wheel side axle 60R is connected to a differential device 70R, and the differential device 70R is connected to the motor shaft 65 of the rear motor 4 via a connecting portion 75 formed of a pair of universal joints.

  As shown in FIG. 2, the motor / generator 5 is connected to the output shaft of the engine 1 and functions as a generator that is driven by the engine 1 to generate three-phase AC power. The three-phase AC power is converted into DC power by the M / G inverter 25 and supplied to the front inverter 23 and the rear inverter 24. When the charging rate is reduced to a predetermined value, the DC power converted by the M / G inverter 25 is also supplied to the storage element 7 via the converter 27, and the storage element 7 is charged.

  The M / G inverter 25, the front inverter 23, and the rear inverter 24 are power converters that are driven by an inverter drive signal from the main controller 20, and convert DC power into AC power or AC power into DC power. M / G inverter 25, front inverter 23, and rear inverter 24 are connected to power storage element 7 via converter 27. Converter 27 increases or decreases the charge / discharge voltage of power storage element 7.

  The electric storage element 7 is an electric double layer capacitor capable of storing electric power generated by a certain amount of electric work (for example, work of several tens of kW for several seconds) and discharging electric charge stored at a desired time. The power storage element 7 is charged with DC power converted by the front inverter 23, the rear inverter 24, and the M / G inverter 25.

  The DC power converted by the M / G inverter 25 and / or the DC power output from the storage element 7 is converted into three-phase AC power by the front inverter 23 and the rear inverter 24. The front motor 3 and the rear motor 4 are driven by three-phase AC power (also referred to as a motor drive signal) converted by the front inverter 23 and the rear inverter 24, respectively, and generate rotational torque. The rotational torque generated by the front motor 3 and the rear motor 4 is transmitted to the front wheel 113 and the rear wheel 123 via the differential devices 70F and 70R and the axles 60F and 60R.

  On the other hand, during the regenerative braking operation, the front motor 3 and the rear motor 4 are rotated by the rotational torque transmitted from the front wheels 113 and the rear wheels 123, and three-phase AC power is generated. The three-phase AC power generated by the front motor 3 and the rear motor 4 is converted into DC power by the front inverter 23 and the rear inverter 24, respectively, and is supplied to the power storage element 7 via the converter 27. It is charged by the DC power converted by the rear inverter 24.

  The main controller 20 and the engine controller 21 are configured to include an arithmetic processing unit having a CPU and a storage device such as ROM and RAM, and other peripheral circuits. The main controller 20 controls the entire system including the traveling system and the hydraulic work system of the wheel loader 100, and controls each part so that the entire system exhibits the best performance.

  The main controller 20 includes a forward / reverse selector switch 51, an accelerator pedal sensor 52, a vehicle speed sensor 53, a brake pedal sensor 54, an engine rotation sensor 50, a rotation sensor 59F for the front motor 3, a rotation sensor 59R for the rear motor 4, and a parking brake switch. Each of the signals from 55 is input.

  The forward / reverse selector switch 51 outputs a forward / reverse switch signal for commanding forward / reverse of the vehicle to the main controller 20. The accelerator pedal sensor 52 detects the pedal operation amount of an accelerator pedal (not shown) and outputs an accelerator signal to the main controller 20. The vehicle speed sensor 53 detects the vehicle travel speed (vehicle speed) of the wheel loader 100 and outputs a vehicle speed signal to the main controller 20. The brake pedal sensor 54 detects a pedal operation amount of a brake pedal (not shown) and outputs a service brake signal to the main controller 20. The parking brake switch 55 is a switch for operating the parking brake.

  The engine rotation sensor 50 detects the actual rotation speed of the engine 1 and outputs an actual rotation signal to the main controller 20. Traveling motor rotation sensors 59F and 59R are resolvers, for example, and output signals corresponding to the rotations of front motor 3 and rear motor 4. The motor rotation signals are respectively input to the main controller 20. Note that any one of the traveling motor rotation sensors 59F and 59R and the vehicle speed sensor 53 may be omitted. For example, the vehicle speed sensor 53 may be omitted, and the vehicle speed may be calculated based on the motor rotation speed detected by the travel motor rotation sensor 59.

  The main controller 20 controls the engine 1, the front inverter 23, and the rear inverter 24 so that the front motor 3 and the rear motor 4 output a required torque corresponding to vehicle information including the pedal operation amount of an accelerator pedal (not shown). . A method for calculating the required torque of the front motor 3 and the rear motor 4 will be described later.

  The main controller 20 calculates the power generation amount necessary for the front motor 3 and the rear motor 4 based on the calculated motor required torque. The main controller 20 calculates an engine target speed for obtaining a predetermined power generation amount by the motor / generator 5, and outputs an engine drive control signal to the engine controller 21 based on the calculated engine target speed. A drive signal for converting the three-phase AC power generated by the generator 5 into DC power is output to the M / G inverter 25.

  The engine controller 21 compares the actual rotational speed Na of the engine 1 detected by the engine rotational sensor 50 with the engine target rotational speed Nt from the main controller 20, and determines the actual rotational speed Na of the engine 1 as the engine target rotational speed. A fuel injection device (not shown) is controlled so as to approach Nt.

  The main controller 20 operates the vehicle so that the charging rate (SOC: State Of Charge) of the storage element 7 does not fall below a predetermined lower limit and does not exceed a predetermined upper limit, that is, vehicle speed information, The engine 1, the M / G inverter 25, the front inverter 23 and the rear inverter 24, the converter 27, and the like are controlled according to the pedal operation amount of the accelerator pedal, the charging rate, and the like.

  As described above, the main controller 20 calculates a motor request torque that is a torque required for the front motor 3 and the rear motor 4 during traveling. FIG. 3 is a diagram showing a motor required torque map (motor characteristics). The motor required torque map is a map that represents a torque curve (characteristic M2) of the front motor 3 and a torque curve (characteristic M1) of the rear motor 4.

  As shown in FIG. 3, the front motor 3 and the rear motor 4 have different characteristics. The front motor 3 is a high-speed type motor (characteristic M2) that cannot drive a large torque in a low-speed range but can be driven to a high-speed rotation, and the rear motor 4 cannot output a torque to a high-speed rotation. This is a low speed motor (characteristic M1) capable of producing a large torque in a low speed range. The front motor 3 and the rear motor 4 have different operation areas that can be driven with high efficiency. Therefore, it is possible to drive the motor with high efficiency in a wide range of power performance required for the vehicle.

  Each of the characteristic M1 and the characteristic M2 is set so that the motor required torque is in inverse proportion to the rotation speed of the rear motor 4 and the front motor 3 while being proportional to the accelerator signal, and is stored in the storage device in the main controller 20. Yes.

  That is, the main controller 20 receives the accelerator signal and the outputs of the front motor 3 and the rear motor 4 so that the outputs of the front motor 3 and the rear motor 4 increase or decrease in accordance with the increase or decrease of the accelerator signal input from the accelerator pedal sensor 52. Relationship is set. The main controller 20 determines a torque curve according to the accelerator signal, and determines the motor required torque from the rotational speeds of the front motor 3 and the rear motor 4 using the torque curve. The required torque of each of the front motor 3 and the rear motor 4 is determined, a motor drive signal is generated by a known method based on the torque, and the motor drive signal is output to the front inverter 23 and the rear inverter 24.

  In the present embodiment, the required torques of the rear motor 4 and the front motor 3 are determined so as to obtain the highest motor efficiency. FIG. 4 is a functional block diagram for explaining a torque determination method for the rear motor 4 and the front motor 3. As shown in FIG. 4, the main controller 20 functionally includes a vehicle travel output calculation unit 91, a travel motor torque calculation unit 92, and a limiter 93.

  When an accelerator signal, a brake signal, a forward / reverse switch signal, and a current vehicle travel speed (vehicle speed) corresponding to an operation command from the driver are input to the vehicle travel output computation unit 91, the vehicle travel output computation unit 91 A travel output command requested from the vehicle is calculated.

  When the calculated travel output command is input to travel motor torque calculation unit 92, travel motor torque calculation unit 92 calculates the torque required for each of rear motor 4 and front motor 3. At this time, when the required torque of the rear motor 4 and the required torque of the front motor 3 are summed, a torque value corresponding to the travel output command required by the vehicle described above is obtained.

  The traveling motor torque calculation unit 92 has efficiency data tables for the rear motor 4 and the front motor 3 therein, and based on the efficiency data table, torque distribution that provides the highest motor efficiency with respect to the traveling output command. To decide. When a torque command is output to a control device (not shown) included in each of the rear inverter 24 and the front inverter 23, the limiter 93 performs a torque limiting process based on the limitations of the hybrid system and the vehicle. The rear motor torque command and the front motor torque command are used. The rear inverter 24 and the front inverter 23 supply three-phase AC power to the armature windings (stator windings) of the rear motor 4 and the front motor 3 based on the rear motor torque command and the front motor torque command, The rotor 3r, 4r is rotated to perform the traveling operation of the vehicle.

  As described above, in this embodiment, the two motors having different characteristics are used to distribute the torque to the vehicle request so that the motor efficiency is maximized. Therefore, it is possible to achieve downsizing and high efficiency of the driving device.

  The front motor 3 and the rear motor 4 according to the present embodiment are travel motors that are preferably used for travel of a hybrid vehicle, and are synchronous motors that include an induction motor having a cage rotor and a rotor having a permanent magnet. is there. Hereinafter, an induction motor will be described as an example.

  FIG. 5 is a schematic cross-sectional view of the front motor 3 and the rear motor 4 according to the present embodiment. As shown in FIG. 5A, the front motor 3 includes a housing 30 and a stator 3s held inside the housing 30, and the stator 3s includes a cylindrical stator core (stator core) 32 and a stator. Winding 33 is provided. Inside the stator core 32, a rotor (rotor) 3r is rotatably held through a gap. The rotor 3r includes a cylindrical rotor core 35, a conductor bar (not shown), and an end ring (short-circuit ring) 36. A cylindrical rotor shaft (rotary shaft) 63 is provided in a hollow portion of the rotor core 35. The rotor core 35 is fixed to the motor shaft 63.

  The housing 30 includes a cylindrical center bracket 30a and a pair of end brackets 30b and 30c provided with bearings 38a and 38b. A cooling jacket 31 is interposed between the center bracket 30 a and the stator core 32. The motor shaft 63 is rotatably held by bearings 38a and 38b provided on the end brackets 30b and 30c, respectively.

  As shown in FIG. 5 (b), the rear motor 4 has a housing 40 and a stator 4s held inside the housing 40. The stator 4s has a cylindrical stator core (stator core) 42 and a stator winding. Line 43. Inside the stator core 42, a rotor (rotor) 4r is rotatably held through a gap. The rotor 4 r includes a cylindrical rotor core 45, a conductor bar (not shown), and an end ring (short-circuit ring) 46. A hollow portion of the rotor core 45 has a columnar rotor shaft (rotary shaft) 65. The rotor core 45 is fixed to the motor shaft 65.

  The housing 40 includes a cylindrical center bracket 40a and a pair of end brackets 40b and 40c provided with bearings 48a and 48b. A cooling jacket 41 is interposed between the center bracket 40 a and the stator core 42. The motor shaft 65 is rotatably held by bearings 48a and 48b provided on the end brackets 40b and 40c, respectively.

  As described above, the rear motor 4 is a low-speed motor having a characteristic that the torque is larger than that of the front motor 3 in the low-speed region and the torque is smaller than that of the front motor 3 in the high-speed region. The rear motor 4 is configured to be larger in size (the radial direction length of the rotor 4r) and larger in mass than the front motor 3 that is a high-speed motor. That is, the physique of the rear motor 4 is larger than the physique of the front motor 3.

  FIG. 6 is a diagram schematically showing the rear motor 4 and the front motor 3 mounted on the wheel loader 100. FIG. 7 is a plan view of the wheel loader 100. In FIG. 6, the outer shape of the wheel loader 100 is indicated by a two-dot chain line. In FIG. 7, the cab 121, the engine compartment 140, the arm 111, the bucket 112, and the like are not shown.

  The wheel loader 100 is equipped with a counterweight 124 for balancing the rear of the vehicle in order to carry out various operations such as transporting heavy objects with a working device such as a bucket 112 installed in front of the vehicle (FIG. 1). reference). Therefore, it is preferable to mount a low-speed motor that becomes a heavy object in the opposite direction of the work device, that is, behind the vehicle.

  The front vehicle body 110 has a front frame 119 formed in a substantially box shape having an upper plate 119U, a lower plate 119L, and a pair of side plates 119S constituting the front frame 119. A front motor 3 is provided. The rear vehicle body 120 has a rear frame 129 to which the cab 121 and the engine compartment 140 are attached. The rear motor 4 is disposed in the rear frame 129. A side plate 129 </ b> S of the rear frame 129 is provided on the side of the rear motor 4.

  Since the front motor 3 is surrounded by the upper plate 119U, the lower plate 119L, and the pair of side plates 119S, it is protected from earth and sand during excavation work. Since the rear motor 4 is located below the cab 121 and is surrounded by the cab 121 and the side plate 129S, it is protected from earth and sand during excavation work.

  FIG. 8 is an enlarged view of a main part of FIG. The wheel loader 100 includes a disc-type parking brake device 80. The parking brake device 80 is a negative parking brake. The parking brake device 80 includes a parking brake disc (brake disc) 81 provided on the vehicle front side (front side) of the motor shaft 65 of the rear motor 4 and an outer periphery of the brake disc 81 so as to hold the parking brake on the wheel loader 100. And a pair of brake pads 82 for applying force. The parking brake device 80 includes a parking brake hydraulic cylinder 83 that controls operation / non-operation of the parking brake, a brake caliper 85 provided with the parking brake hydraulic cylinder 83, and a parking brake hydraulic cylinder 83 according to a parking brake operation command. And a hydraulic circuit 84 for drive control.

  FIG. 9 is a diagram illustrating an example of a cross-sectional structure of the parking brake device 80 and an attached state of the parking brake device 80. FIG. 10 is an exploded view of the rear motor 40 and the parking brake device 80. FIG. 11 is a perspective view of the vicinity of the connection shafts 101U and 101L of the wheel loader 100 in which the front vehicle body 110 and the rear vehicle body 120 are bent to the right by the connection shafts 101U and 101L when viewed from the left front. FIG. 12 is a view when the parking brake device 80 is mounted from the front of the parking brake 80, and FIG. 13 is a view when the parking brake device 80 is mounted from above the parking brake 80. is there.

  As shown in FIGS. 9 and 10, a caliper mounting bracket 410 is provided on the front end bracket 40b of the housing 40 of the rear motor 4 as an electric motor side mounting portion for mounting the brake caliper 85 of the parking brake device 80. It has been. The caliper mounting bracket 410 is provided with a screw hole 411 into which a caliper mounting bolt 86 described later is screwed.

  The brake disc 81 of the parking brake device 80 is fixed to the motor shaft 65 of the rear motor 4 and rotates together with the motor shaft 65. The parking brake hydraulic cylinder 83 is fixed to the brake caliper 85. When the supply of pressure oil from a hydraulic path 84 to be described later is cut off, the parking brake hydraulic cylinder 83 pushes the piston rightward in the drawing in FIG. To activate the parking brake. Also, the parking brake hydraulic cylinder 83 releases the parking brake by pushing the piston back to the left in FIG. 9 against the biasing force of the built-in spring by the pressure oil from the hydraulic path 84. That is, the parking brake device 80 is a negative parking brake device.

  The brake caliper 85 is attached to the caliper mounting bracket 410 by caliper mounting bolts 86. As described above, the caliper mounting bolt 86 is screwed into the screw hole 411 of the caliper mounting bracket 410 and fixed to the caliper mounting bracket 410. The brake caliper 85 is movable in the extending direction (thrust direction) of the caliper mounting bolts 86 so that the pair of brake pads 82 sandwich the both surfaces of the brake disc 81 with the same force. As described above, the brake caliper 85 is attached to the housing 40 (end bracket 40b) of the rear motor 4 in a state in which the brake caliper 85 is movable in the extending direction of the caliper mounting bolt 86. Is written.

  As shown in FIG. 11, when the front vehicle body 110 and the rear vehicle body 120 are bent, for example, to the right side by the connecting shafts 101U and 101L, the parking brake device 80 is exposed in the vicinity of the connecting shafts 101U and 101L. Therefore, the maintainability of the parking brake device 80 is good.

  FIG. 14 is a hydraulic circuit diagram mainly showing a portion according to the present embodiment in the hydraulic circuit of the wheel loader 100. The hydraulic circuit 84 includes an electromagnetic switching valve 841, a pressure accumulator (accumulator) 842, and a check valve 843. The pressure oil supplied from the working hydraulic pump 10 to the parking brake hydraulic cylinder 83 is controlled by the electromagnetic switching valve 841. Pressure oil from the working hydraulic pump 10 is supplied to the electromagnetic switching valve 841 via the check valve 843. An accumulator 842 is attached to a pipe connecting the check valve 843 and the electromagnetic switching valve 841.

  The solenoid of the electromagnetic switching valve 841 is demagnetized by the parking brake operation signal from the main controller 20, and the solenoid of the electromagnetic switching valve 841 is excited by the parking brake release signal from the main controller 20. When the solenoid of the electromagnetic switching valve 841 is demagnetized, the spool of the electromagnetic switching valve 841 is switched to the low position, the supply of pressure oil to the parking brake hydraulic cylinder 83 is cut off, and the parking brake hydraulic cylinder 83 and A hydraulic oil tank (not shown) is connected. Accordingly, the parking brake hydraulic cylinder 83 pushes out the piston by the biasing force of the built-in spring. As a result, the parking brake operates as described above.

  When the solenoid of the electromagnetic switching valve 841 is excited, the spool of the electromagnetic switching valve 841 is switched to the A position, and pressure oil is supplied to the parking brake hydraulic cylinder 83. As a result, the parking brake hydraulic cylinder 83 pushes back the piston against the biasing force of the built-in spring. As a result, the parking brake is released as described above.

  That is, the operator performs an operation to command the operation of the parking brake. For example, when a parking brake operation command is output from the parking brake switch 55, a parking brake operation signal is output from the main controller 20 to the electromagnetic switching valve 841. As a result, as described above, the parking brake hydraulic cylinder 83 contracts, and the brake pad 82 clamps the parking brake disk 81 by the biasing force of the spring, and the parking brake is operated.

  For example, when a parking brake release command is output from the parking brake switch 55, the parking brake release signal is output from the main controller 20 to the electromagnetic switching valve 841. As a result, as described above, the parking brake hydraulic cylinder 83 extends against the bias of the spring, the parking brake disk 81 is released from being held by the brake pad 82, and the parking brake is deactivated.

  As described above, the hydraulic circuit 84 is provided with the accumulator 842. The accumulator 842 holds (accumulates) the pressure oil from the working hydraulic pump 10. The pressure oil accumulated in the accumulator 842 is held in the accumulator 842 by the check valve 843 and the electromagnetic switching valve 841 switched to the B position even after the working hydraulic pump 10 is stopped (that is, after the engine 1 is stopped). Is done.

  For example, an electric circuit is configured so that the solenoid of the electromagnetic switching valve 841 can be energized even when the engine 1 is stopped, so that even when the engine 1 is stopped, parking is performed by the pressure oil accumulated in the accumulator 842. The brake can be released. Further, by configuring the electromagnetic switching valve 841 to be switched to the A position by manual operation, the accumulator can be used even when the engine 1 is stopped or when the solenoid of the electromagnetic switching valve 841 cannot be energized for some reason. The parking brake can be released by the pressure oil accumulated in 842. In other words, the brake release pressure may be supplied to the parking brake device 80 by the pressure oil held by the accumulator 842.

The wheel loader 100 of the present embodiment described above has the following operational effects.
(1) The parking brake device 80, which is a disc-type hydraulic negative brake, is configured to be used as a parking brake device of a series hybrid type wheel loader 100. As a result, for example, when an electric parking brake device is employed, it is possible to avoid a problem that the parking brake cannot be released due to a problem in the electric system for rotationally driving the electric motor of the parking brake. Therefore, it is possible to prevent the trouble that the wheel loader 100 cannot move or work because the parking brake cannot be released, which contributes to the improvement of work efficiency. In addition, since it can be easily adopted for existing wheel loaders, it is possible to minimize the time and effort required for changing the design and the processing for mounting, thereby suppressing an increase in cost.

(2) Since the brake release pressure is supplied to the parking brake device 80 by the pressure oil held by the accumulator 842, parking is performed by the pressure oil accumulated in the accumulator 842 even when the engine 1 is stopped. The brake can be released. Thereby, since the parking brake can be released without starting the engine 1 while the engine 1 is stopped, convenience is improved. Further, as described above, by configuring the electromagnetic switching valve 841 to be switched to the position B by manual operation, when the engine 1 is stopped or when the solenoid of the electromagnetic switching valve 841 cannot be energized for some reason. Even in such a case, the parking brake can be released by the pressure oil accumulated in the accumulator 842. As a result, it is possible to prevent a failure that the parking load cannot be released and the wheel loader 100 cannot move or work, which contributes to an improvement in work efficiency.

(3) The brake caliper 85 is attached to the housing 40 of the rear motor 4. Accordingly, for example, compared to the case where the brake caliper 85 is attached to the strength member of the rear vehicle body 120, the brake caliper 85 becomes difficult to move with respect to the input from the brake disc 81 when the parking brake is operated. Stability when parking is improved.

(4) The brake caliper 85 is attached to the housing 40 of the rear motor 4 having an outer diameter larger than that of the front motor 3. Thereby, the distance between the brake caliper 85 and the axis of the motor shaft 65 can be increased, and the braking torque by the parking brake device 80 can be increased. Therefore, the stability of the wheel loader 100 during parking is improved.

(5) When the front vehicle body 110 and the rear vehicle body 120 are bent left and right by the connecting shafts 101U and 101L, the parking brake device 80 is exposed in the vicinity of the connecting shafts 101U and 101L. Thereby, the maintainability of the parking brake apparatus 80 becomes favorable.

---- Modified example ---
(1) In the above description, the case where the physique of the rear motor 4 is larger than the physique of the front motor 3 has been described, but the present invention is not limited to this. For example, when the front motor 3 is larger than the rear motor 4, the brake caliper 85 may be attached to the rear end bracket 30c of the front motor 3.

(2) In the above description, the case where the physique of the rear motor 4 is larger than the physique of the front motor 3 has been described, but the present invention is not limited to this. For example, the outer diameter of the front motor 3 and the outer diameter of the rear motor 4 may be the same. In this case, the brake caliper 85 may be attached to the front end bracket 40b of the rear motor 4, or the brake caliper 85 may be attached to the rear end bracket 30c of the front motor 3. Good.

(3) In the above description, the wheel loader 100 is provided with two units of the front motor 3 and the rear motor 4 as the electric motor for traveling, but the present invention is not limited to this. For example, one traveling electric motor may be used. In this case, what is necessary is just to comprise so that the brake caliper 85 may be attached to this one electric motor for driving | running | working.

(4) In the above description, the caliper mounting bracket 410 is provided on the front end bracket 40b of the rear motor 4, and the caliper mounting bolt 86 is screwed into the screw hole 411 of the caliper mounting bracket 410, so that the brake caliper 85 is Although configured to be attached to the housing 40 of the rear motor 4, the present invention is not limited to this. For example, as shown in FIG. 15, a base 420 is attached to the front end bracket 40 b of the rear motor 4, and a caliper mounting bolt 86 is screwed into a screw hole 421 provided in the base 420 so that the brake caliper 85 is attached. You may comprise so that it may attach to the housing 40 of the rear motor 4. FIG.

(5) In the above description, an example in which there are two traveling motors and one example has been shown, but the present invention can also be applied to an electric traveling vehicle having three or more traveling motors.
(6) In the above description, the wheel loader 100 employs the series hybrid traveling device in which the front motor 3 and the rear motor 4 are driven by the electric power generated by the motor / generator 5. Is not limited to this, and various forms can be adopted.

(7) In the above description, the embodiment in which the present invention is applied to a hybrid wheel loader has been described. However, the present invention relates to a traveling electric dump truck and other industrial vehicles in which traveling driving force is obtained by an electric motor. It can be applied to an electric traveling vehicle such as.
(8) You may combine each embodiment and modification which were mentioned above, respectively.

  The present invention is not limited to the embodiment described above, and includes a rotor, a stator, a housing that holds the rotor and the stator inside, and a traveling motor that provides traveling driving force, and a disk. This type of hydraulic negative brake has a parking brake device that gives parking brake force to the brake disc by parking brake command and releases parking brake force by hydraulic brake release pressure, and a pressure accumulator, which is held by the pressure accumulator A brake release device that supplies brake release pressure to the parking brake device by pressure oil, the parking brake device having a brake disk, a brake pad, and a brake caliper that presses the brake pad against the brake disk, Has a motor-side mounting part where the brake caliper can be mounted on the housing. , Brake caliper, is intended to include motorized vehicles of various structures, characterized in that attached to the motor side mounting portion.

1 engine, 3 front motor, 4 rear motor, 20 main controller, 40 housing, 40b, 40c end bracket, 55 parking brake switch, 80 parking brake device, 81 parking brake disc (brake disc), 82 brake pad, 83 parking brake Hydraulic cylinder, 84 hydraulic circuit, 85 brake caliper, 86 caliper mounting bolt, 100 wheel loader, 110 front vehicle body, 120 rear vehicle body, 410 caliper mounting bracket, 841 electromagnetic switching valve, 842 pressure accumulator (accumulator), 843 check valve

Claims (4)

An articulated electric traveling vehicle in which a front vehicle body and a rear vehicle body are bent left and right with a connecting shaft as a rotation axis,
A traveling motor having a rotor, a stator, and a housing that holds the rotor and the stator therein, and that provides traveling driving force;
A disc type hydraulic negative brake, which applies a parking brake command to the brake disc by a parking brake command, and releases the parking brake force by a hydraulic brake release pressure; and
A brake release device having a pressure accumulator and supplying the brake release pressure to the parking brake device by pressure oil held by the pressure accumulator;
The parking brake device includes the brake disc, a brake pad, and a brake caliper that presses the brake pad against the brake disc,
The electric motor for traveling has an electric motor side attaching portion to which the brake caliper is attached to the housing,
The brake caliper is attached to the motor side attachment portion ,
The travel motor includes a first travel motor provided on the front vehicle body and a second travel motor provided on the rear vehicle body,
The housing of the second traveling motor has a larger outer diameter than the housing of the first traveling motor,
The electric traveling vehicle is characterized in that the motor side mounting portion is provided on an end surface on a front side of a housing of the second traveling electric motor . An articulated electric traveling vehicle in which a front vehicle body and a rear vehicle body are bent left and right with a connecting shaft as a rotation axis,
A traveling motor having a rotor, a stator, and a housing that holds the rotor and the stator therein, and that provides traveling driving force;
A disc type hydraulic negative brake, which applies a parking brake command to the brake disc by a parking brake command, and releases the parking brake force by a hydraulic brake release pressure; and
A brake release device having a pressure accumulator and supplying the brake release pressure to the parking brake device by pressure oil held by the pressure accumulator;
The parking brake device includes the brake disc, a brake pad, and a brake caliper that presses the brake pad against the brake disc,
The electric motor for traveling has an electric motor side attaching portion to which the brake caliper is attached to the housing,
The brake caliper is attached to the motor side attachment portion ,
The travel motor includes a first travel motor provided on the front vehicle body and a second travel motor provided on the rear vehicle body,
The housing of the first traveling motor has a larger outer diameter than the housing of the second traveling motor,
The electric traveling vehicle is characterized in that the electric motor side mounting portion is provided on an end surface on the rear side of the housing of the first electric motor for traveling. In the electric traveling vehicle according to claim 1 or 2 ,
When the front vehicle body and the rear vehicle body are bent in either the left or right direction with the connecting shaft as a rotation axis, the parking brake device is exposed to the space in the left or right direction of the connecting shaft. An electrically driven vehicle characterized by the above. In the electric traveling vehicle according to any one of claims 1 to 3 ,
Further comprising a pedestal attached to the motor side attachment portion,
The electric vehicle according to claim 1, wherein the brake caliper is attached to the electric motor side attaching portion via the base attached to the electric motor side attaching portion.

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