JP2005067496A - Parking brake device of paving machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid sudden stop of a vehicle body by controlling the operation of a negative brake even when a parking switch is mistakenly turned on while the vehicle body is running. <P>SOLUTION: A rotation sensor 23 is provided to detect the running condition, and the number of rotation of a driving wheel 14 is detected. The driving wheel 14 is braked by the operation of a negative brake 19, and during the running condition, a control valve 22 is changed over by the control signal from a controller 30 to release the operation of the negative brake. When the parking switch 25 is turned on while a vehicle body is running, the negative brake 19 is not operated if the number of rotation of the driving wheel 14 is not reduced to a preset value. When the number of rotation of the driving wheel 14 is reduced to the preset value, the negative brake 19 is operated to set the parking brake in an operational state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a parking brake device for a paving machine, and more particularly to a parking brake device for a paving machine provided with a negative brake for braking driving wheels.

  A conventional wheeled pavement machine is known that includes a brake cylinder that brakes a drive shaft in order to brake left and right drive wheels. When pressure oil is not supplied to the brake cylinder, the brake is in a braking state, and when traveling, a so-called negative brake is used that releases pressure by supplying pressure oil to the brake cylinder. (For example, refer to Patent Document 1).

Generally, in this kind of paving machine, by turning on a parking switch, the negative brake is actuated to brake the left and right drive wheels, thereby forming a parking brake. Then, by turning off the parking switch, the operation of the negative brake is released and the left and right drive wheels are released, that is, the parking brake is inactivated. Further, the parking brake is inactivated even when the travel switch is turned on.
JP 2001-32207 A (pages 1 to 5, FIG. 1).

  Conventional parking brake devices for paving machines are extremely dangerous when the parking switch is turned on even during traveling because the negative brake is activated and the driving wheels are suddenly braked, causing the vehicle body to stop suddenly.

  Therefore, even if the parking switch is accidentally turned on while the vehicle is running, there is a technical problem to be solved in order to check the operation of the negative brake and avoid the sudden stop of the vehicle, The present invention aims to solve this problem.

  The present invention has been proposed to achieve the above object, and the invention according to claim 1 comprises a negative brake for braking the left and right drive wheels, and a release means for releasing the operation of the negative brake. In the paving machine configured to operate the negative brake by a parking switch, a detecting means for detecting a traveling state is provided, and when the parking switch is turned on, it is detected that the traveling state is lowered to a preset traveling state. When the means detects, a parking brake device for a paving machine is provided, which is provided with a control means for switching the release means to operate a negative brake.

  The detection means detects the running state, and when the vehicle body falls to a preset running state due to a decrease in the rotational speed of the driving wheel or the running speed of the vehicle body, the control means switches the release means to operate the negative brake. To activate the parking brake.

  According to a second aspect of the present invention, there is provided a pavement comprising a negative brake for braking the left and right drive wheels, and a release means for releasing the operation of the negative brake, wherein the negative brake is operated by a parking switch. In the machine, there is provided a detecting means for detecting a traveling state, and when the detecting means detects that the vehicle body is in a traveling stopped state, the paving is provided with a control means for switching the releasing means to operate a negative brake. A parking brake device for a machine is provided.

  When the detection means detects the traveling state and the vehicle body is in a traveling stop state because the rotational speed of the driving wheel is zero or the traveling speed of the vehicle body is zero, the control means switches the releasing means to activate the negative brake. Turn on the parking brake.

  According to a third aspect of the present invention, there is provided a paving machine provided with a switching valve as a releasing means, and switching the switching valve according to a control signal of the control means to supply pressure oil to the negative brake to release the operation of the negative brake. A parking brake device is provided.

  When the switching valve provided as the release means is an electromagnetic type, the solenoid is excited by the control signal of the control means and switched. When the switching valve is of a pilot type, the pilot port is switched by the pilot pressure applied by the control signal of the control means. When the switching valve is switched, pressure oil is supplied to the negative brake. If so, the operation of the negative brake is released and the parking brake is deactivated.

  According to a fourth aspect of the present invention, a paving machine is provided with a rotation sensor as a detecting means, and is configured to detect a traveling state from the rotational speed of the driving wheel or the rotational speed of the pump or motor proportional to the rotational speed of the driving wheel. A brake device is provided.

  A rotation sensor provided as detection means detects the running state by reading the number of rotations of the drive wheels. Alternatively, the running state is detected by reading the number of revolutions of the pump or motor proportional to the number of revolutions of the drive wheels. That is, when it is detected that these rotational speeds have decreased to a preset rotational speed, the release means is switched by the control signal of the control means to activate the negative brake.

  According to a fifth aspect of the present invention, there is provided a parking brake device for a paving machine, which is provided with a speed sensor as detecting means and is configured to detect a traveling state from a traveling speed of a vehicle body.

  A speed sensor provided as a detecting means detects the traveling state by reading the traveling speed of the vehicle body. That is, when it is detected that the travel speed of the vehicle body has decreased to a preset travel speed, the release means is switched by the control signal of the control means to activate the negative brake.

  According to the first aspect of the present invention, when the detecting means detects that the driving state has been lowered to the preset traveling state, the control means switches the releasing means to operate the negative brake. Even when is turned on, it is possible to prevent the sudden stop of the vehicle body by restraining the operation of the negative brake and contribute to the improvement of safety.

  According to the second aspect of the present invention, when the detecting means detects that the vehicle body is stopped, the control means switches the releasing means to operate the negative brake, so that the parking brake is automatically operated when the vehicle body is stopped. Thus, forgetting to apply the parking brake can be prevented, which can contribute to an improvement in safety.

  According to the third aspect of the present invention, the switching valve is provided as the release means, and the switching valve is switched by the control signal of the control means to supply the pressure oil to the negative brake. Therefore, the operation of the negative brake is reliably released with a simple configuration. can do.

  In the invention according to claim 4, a rotation sensor is provided as a detecting means, and the running state is detected from the rotational speed of the driving wheel or the rotational speed of the pump or motor proportional to the rotational speed of the driving wheel. The running state can be detected.

  According to the fifth aspect of the present invention, since the speed sensor is provided as the detecting means and the traveling state is detected from the traveling speed of the vehicle body, the traveling state can be reliably detected with a simple configuration.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a wheel-type asphalt finisher 10 as an example of a paving machine. A hopper 12 is arranged at the front of a vehicle body 11, and the asphalt mixture put into the hopper 12 is moved backward by a bar conveyor (not shown). It is conveyed, distributed from the rear part of the vehicle body 11 to the road surface, and spread by a screed 13 to an equal thickness. Reference numeral 14 denotes left and right drive wheels, and the drive wheels 14 are driven by a hydraulic motor described later.

  FIG. 2 shows the configuration of the parking brake device of the asphalt finisher 10. The hydraulic pump 16 is driven by the engine 15, and the pressure oil discharged from the hydraulic pump 16 is supplied to the hydraulic motor 17. The rotation of the hydraulic motor 17 is transmitted to the drive wheel 14 via the drive shaft 18.

  The drive shaft 18 is provided with a negative brake 19 for braking the drive wheel 14, and when pressure oil is not supplied to the cylinder 19a of the negative brake 19, the brake piece 19c is urged by the bias of the built-in spring 19b. Presses the drive shaft 18, and the negative brake 19 is in an activated state.

  A brake oil passage 20 is connected to the negative brake cylinder 19a, and pressure oil from a hydraulic pressure source 21 is supplied to and discharged from the negative brake cylinder 19a via a switching valve 22. The solenoid 22a of the switching valve 22 is excited by a control signal from the controller 30.

  Further, a rotation sensor 23 is provided in the vicinity of the drive shaft 18, and as will be described later, the rotation sensor 23 detects the number of rotations of the drive shaft 18 and detects the rotation state of the drive shaft 18. input. Reference numeral 24 is a travel switch, and 25 is a parking switch.

  In the state shown in FIG. 2, since the parking switch 25 is on and the switching valve 22 is in the normal position (A), the pressure oil in the cylinder 19a of the negative brake returns to the tank 26, and the built-in spring 19b The negative brake 19 is activated by the urging, and the parking brake is in an activated state.

  When the vehicle is traveling, if the travel switch 24 is turned on, the solenoid 22a of the switching valve 22 is excited by a control signal from the controller 30 as shown in FIG. ). At that time, the pressure oil from the hydraulic source 21 passes through the switching valve 22 and is led out to the brake circuit 20, and the pressure oil is supplied to the cylinder 19a of the negative brake.

  Accordingly, the pressure oil pushes the piston against the spring 19b to pull the brake piece 19c away from the drive shaft 18, releases the operation of the negative brake 19 and deactivates the parking brake. That is, the switching valve 22 serves as a release means for releasing the operation of the negative brake 19. Thus, by turning on the travel switch 24, the parking switch 25 is automatically turned off, and the parking brake is automatically released.

  Note that the switching valve as the release means should not be limited to an electromagnetic switching valve, and although not shown, a pilot switching valve may be used. In the case of a pilot type switching valve, pilot pressure is applied to the pilot port by a control signal from the controller 30, and the switching valve is switched.

  Thus, the switching valve 22 is switched to release the operation of the negative brake 19, and the hydraulic motor 17 is rotated by the pressure oil discharged from the hydraulic pump 16, and the drive wheel 14 is rotated via the drive shaft 18. When driven, the car body starts to travel. If the discharge amount of the hydraulic pump 16 is increased, the flow rate of the hydraulic motor 17 is increased, the rotational speed of the drive wheels 18 is increased, and the traveling speed of the vehicle body is increased.

  The traveling state of the vehicle body is determined by reading the rotation of the drive shaft 18, that is, the rotational speed of the driving wheel 14 by the rotation sensor 23, and the controller 30 calculates the rotational speed of the driving wheel 14 to determine the traveling state of the vehicle body. Alternatively, the rotational speed of the hydraulic pump 16 or the hydraulic motor 17 that is proportional to the rotational speed of the drive wheel 14 is read, and from these detected rotational speeds, the controller 30 calculates the rotational speed of the drive wheel 14 to determine the traveling state of the vehicle body. You may make it discriminate | determine.

  Further, a speed sensor 27 may be provided in place of the rotation sensor 23, and the controller 30 may determine the travel state of the vehicle body from the travel speed of the vehicle body detected by the speed sensor 27. The rotation sensor 23 and the speed sensor 27 serve as detection means for detecting the running state.

  Next, control for stopping the vehicle body travel by operating the parking brake will be described with reference to FIGS. First, the controller 30 reads various switch states and detection signals from sensors, etc. (step 1).

  Subsequently, it is determined whether or not a traveling state in which the parking brake may be operated (hereinafter referred to as a determination reference traveling state SS) has been set (step 2). Here, when the determination reference traveling state SS is not set, the operator newly sets the determination reference traveling state SS (rotation speed and traveling speed) (step 3). The determination reference running state SS can be arbitrarily changed by the operator.

  If the parking switch 25 is on (step 4), the current vehicle running state SN read by the rotation sensor 23 and the speed sensor 27 is compared with a preset criterion running state SS. Then, it is determined whether or not the detected traveling state SN has decreased to the determination reference traveling state SS (step 5).

  In step 5, when the traveling state SN is lowered to the judgment reference traveling state SS, it is determined whether or not the traveling switch 24 is on (step 6). When the traveling switch 24 is off, the switching valve is turned on. The solenoid 22a of 22 is not excited (step 7). At that time, as shown in FIG. 2, the switching valve 22 is switched to the normal position (A), the negative brake 19 is activated, and the parking brake is activated.

  On the other hand, when the parking switch 25 is off at step 4, or when the running state SN does not drop to the criterion running state SS at step 5, or when the running switch 24 is on at step 6, In this case also, the solenoid 22a of the switching valve 22 is excited (step 8). In such a case, as shown in FIG. 3, the switching valve 22 is switched to the offset position (B), the operation of the negative brake 19 is released, and the parking brake is inactivated.

  That is, even if the parking switch 25 is turned on while the vehicle is traveling, the traveling speed is detected by the rotation sensor 23, the speed sensor 27, etc., and the parking brake is not operated when the traveling speed is high. When the traveling speed drops to the set speed, the parking brake is activated.

  It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

The figure shows an embodiment of the present invention.
Side view of a wheeled asphalt finisher. Explanatory drawing which shows the structure of an apparatus when a parking brake is an operation state. Explanatory drawing which shows the structure of an apparatus when a parking brake is a non-operation state. The flowchart of control which operates a parking brake.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Asphalt finisher 11 Car body 14 Drive wheel 19 Negative brake 22 Switching valve 23 Rotation sensor 25 Parking switch 27 Speed sensor 30 Controller

Claims (5)

In a paving machine comprising a negative brake for braking the left and right drive wheels, and a release means for releasing the operation of the negative brake, and configured to operate the negative brake with a parking switch.
Provided is a detecting means for detecting a traveling state, and when the parking switch is turned on, when the detecting means detects that the traveling state has been lowered to a preset traveling state, a controlling means is provided for switching the releasing means to activate the negative brake. A parking brake device for a paving machine. In a paving machine comprising a negative brake for braking the left and right drive wheels and a release means for releasing the operation of the negative brake, and configured to operate the negative brake with a parking switch.
A pavement characterized by comprising a detecting means for detecting a running state, and a control means for switching the release means to activate a negative brake when the detecting means detects that the vehicle body is in a running stop state. Mechanical parking brake device.   The paving machine according to claim 1 or 2, wherein a switching valve is provided as a releasing means, and the switching valve is switched by a control signal of the control means to supply pressure oil to the negative brake to release the operation of the negative brake. Parking brake device.   The paving machine according to claim 1, 2 or 3, wherein a rotation sensor is provided as a detection means, and the running state is detected from the rotation speed of the drive wheel or the rotation speed of the pump or motor proportional to the rotation speed of the drive wheel. Parking brake device.   4. A parking brake device for a paving machine according to claim 1, wherein a speed sensor is provided as a detecting means so as to detect a traveling state from a traveling speed of the vehicle body.

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