JP5137919B2 - Overheat determination device and overheat warning device for brake device - Google Patents

Description

  The present invention relates to an overheat determination device and an overheat alarm device for a vehicle brake device.

  In Japanese Utility Model Laid-Open No. 52-113185, a temperature detector is provided on the back plate near the sliding contact portion between the brake drum and the brake lining, and the temperature detector detects the heat generation state of the sliding contact portion due to the brake action. A heat generation alarm device for a brake device that emits a noise is disclosed.

Japanese Utility Model Publication No. 52-113185

  In a brake device that brakes a wheel by sliding a friction braking member on the vehicle body side against a rotating member on the wheel side with a pressing force corresponding to the pressure of the compressed air supplied based on a brake pressure signal, the compressed air supply path When deficiencies occur and the driver releases the brake operation, compressed air continues to be supplied, and the friction braking member on the vehicle body side continuously contacts the rotating member on the wheel side. There is a possibility that the temperature of the member rapidly rises in a short time and reaches an overheating state. In this case, in a device that indirectly detects the temperature of the friction braking member by means of a back plate temperature detector as in the above-mentioned Japanese Utility Model Publication No. 52-113185, the temperature of the friction braking member rapidly rises in a short time and is overheated. However, the temperature detected by the temperature detector does not rise rapidly, and the overheating state of the friction braking member may continue for a long time without generating an alarm.

  Therefore, the present invention can detect at an early stage that the temperature of the frictional braking member suddenly rises in a short time and reaches an overheated state due to a defect in the compressed air supply path. The purpose is to provide a device.

  In order to achieve the above object, a first aspect of the present invention is an overheat determination device in a brake system having an air supply unit and a brake device, wherein the pressure detection unit, the pressure fluctuation determination unit, the time measuring unit, and the overheat determination unit are provided. With.

  The air supply means supplies compressed air to the brake device at a pressure corresponding to the brake pressure signal. The brake device brakes the wheel by sliding the friction braking member on the vehicle body side against the rotating member on the wheel side with a pressing force corresponding to the pressure of the compressed air supplied from the air supply means.

  The pressure detection means detects the pressure of the compressed air supplied from the air supply means to the brake device every predetermined time. The pressure fluctuation determining means determines whether the pressure detected by the pressure detecting means is a positive pressure and a positive pressure stable state in which the amount of pressure fluctuation every predetermined time is maintained within a predetermined range.

  The time measuring means measures the time for which the determination result by the pressure fluctuation determining means is continuously in the positive pressure stable state. The overheat determining means determines that the friction braking member is in an overheated state when the time counted by the time measuring means reaches a predetermined reference time.

  The air supply means may include a relay valve having an inflow port through which compressed air flows and an outflow port for supplying the compressed air flowing in from the inflow port to the brake device at a pressure corresponding to a brake pressure signal. The pressure detecting means may be provided at the outlet of the relay valve.

  In the above configuration, in a state where the air supply means functions properly, that is, in a state where compressed air is supplied in response to a brake pressure signal, the driver does not perform a brake operation (when the brake pedal is not depressed), air The supply means does not supply compressed air to the brake device, the detection pressure of the pressure detection means is maintained at zero, and the pressure fluctuation determination means determines that the pressure is not stable. Therefore, the time measuring means does not start time measurement, and the overheat determining means determines that the friction braking member is not in an overheated state.

  In addition, when the driver depresses the brake pedal with an appropriate brake operation to stop or decelerate the vehicle in a state where the air supply means functions properly, the air supply means is compressed air at a pressure corresponding to the brake pressure signal. Is supplied to the brake device. In this state, even if the pressure of the compressed air supplied to the brake device fluctuates greatly and the fluctuation amount of the detected pressure of the pressure detecting means exceeds the predetermined range, or the fluctuation amount of the detected pressure is maintained within the predetermined range, the reference time Since it is not continuously maintained, the overheat determination means determines that the friction braking member is not overheated.

  On the other hand, there is a defect in the compressed air supply path, and the constant pressure compressed air is continuously supplied to the brake device even though the driver releases the brake operation, and the friction braking member continues to the rotating member. The pressure detection means detects that the pressure detected by the pressure detection means is positive pressure and the fluctuation amount per predetermined time is maintained within a predetermined range, and the pressure fluctuation judgment means judges that the positive pressure is in a stable state. Measures the duration of the positive pressure stable state. Then, when the duration of the positive pressure stable state reaches a predetermined reference time, the overheat determining means determines that the friction braking member is in an overheated state.

  That is, in a situation where the friction braking member continues to come into sliding contact with the rotating member due to a defect in the compressed air supply path and the temperature of the friction braking member suddenly rises in a short time, the positive pressure stable state of the compressed air continues. When the time reaches a predetermined reference time, it is determined that the friction braking member is in an overheated state. For this reason, it can be detected early and reliably that the temperature of the frictional braking member suddenly rises in a short time and reaches an overheated state due to a defect in the compressed air supply path.

  In addition, the overheat determination device includes a temperature detection unit that is attached to the vehicle body side in the vicinity of the friction braking member and detects the ambient temperature of the friction braking member every predetermined time, and every predetermined time detected by the temperature detection unit. Temperature rise rate increase determination means for determining whether or not the temperature increase rate increase state in which the increase rate of the ambient temperature is increasing may be provided based on the ambient temperature. In this case, the overheat determining means is the friction braking member when the time measured by the time measuring means reaches a predetermined reference time and the temperature increase rate increase determining means determines that the temperature increase rate increase state is present. Is determined to be in an overheated state.

  In the above configuration, when the duration time of the positive pressure stable state of the compressed air has reached the reference time and the ambient temperature of the friction braking member is in the temperature increase rate increasing state, the overheat determination means is the friction braking member. Is determined to be in an overheated state. On the other hand, even if the duration of the positive pressure stable state of the compressed air reaches the reference time, if the rate of temperature increase of the ambient temperature of the friction braking member has not increased, the friction braking member is unlikely to reach an overheated state. Therefore, the overheat determination means determines that the friction braking member is not in an overheated state. Therefore, it is possible to more accurately determine whether or not the friction braking member is in a state where it reaches an overheated state.

  In addition, the overheat determination device may include a second timing unit that counts the time during which the determination result by the temperature increase rate increase determination unit is continuously in the temperature increase rate increasing state. In this case, the overheat determining means determines that the friction braking member is in an overheated state when the time measured by the second time measuring means reaches a predetermined second reference time.

  In addition, the overheat determination device includes a temperature increase determination unit that determines whether or not the ambient temperature is rising based on the ambient temperature detected by the temperature detection unit every predetermined time, and a temperature increase determination. You may provide the 3rd time measuring means to time the time when the judgment result by a means becomes a temperature rise state continuously. In this case, the overheat determining means determines that the friction braking member is in an overheated state when the time measured by the third time measuring means reaches a predetermined third reference time.

  In the brake device, as a main factor that the friction braking member reaches an overheated state, in addition to the continuous supply of compressed air due to the incomplete supply path, an inappropriate brake operation by the driver can be cited. For example, in a state where the air supply means functions properly, a driver of a vehicle traveling on a hill continuously repeats a sudden brake operation and release at a short time interval, or continues a weak brake operation. In such a case, the friction braking member may reach an overheated state.

  In the above configuration, the friction braking member is overheated when the temperature increase rate increase state of the ambient temperature continues for the second reference time or when the temperature increase state of the ambient temperature continues for the third reference time. The overheat determination means determines. That is, it is determined whether or not the friction braking member reaches an overheated state based on the fluctuation state of the ambient temperature of the friction braking member and the duration thereof. Therefore, it is possible to detect at an early stage that the friction braking member reaches an overheated state due to an inappropriate brake operation by the driver.

  The brake device may be a drum brake in which a lining as a friction braking member is slidably contacted with a brake drum as the rotating member, and the temperature detecting means is fixed to a brake shoe to which the lining is fixed and the vehicle body side. Attach to an anchor pin bracket that supports the brake shoe in a swingable manner, an axle tube that is fixed to the vehicle body and that supports the wheel to rotate, or a dust cover that is fixed to the vehicle body and covers the inner side in the vehicle width direction of the lining. Also good.

  Moreover, the 2nd aspect of this invention is an overheat warning apparatus in the said brake system provided in the trailer pulled by a tractor, Comprising: The said overheat determination apparatus and an alerting | reporting means are provided.

The overheat determination device receives pressure information indicating the pressure detected by the pressure detection means and temperature information indicating the ambient temperature detected by the temperature detection means by radio signals, and receives the radio signal transmitted by the transmission means. Receiving means. The pressure detection means, the temperature detection means, and the transmission means are provided on a trailer that is pulled by a tractor. The pressure fluctuation determining means, the time measuring means, the temperature rise rate increase determining means, the overheat determining means, and the receiving means are provided in the tractor.

The receiving means outputs the received pressure information to the pressure fluctuation determining means, and outputs the received temperature information to the temperature increase rate increase determining means. The notification means is provided in the passenger compartment of the tractor, and when the overheat determination means determines that the friction braking member is in an overheated state, notifies the driver in the passenger compartment.

  In the above configuration, the driver in the vehicle compartment of the tractor can recognize early from the notification from the notification means that the friction braking member is extremely likely to be overheated or overheated. By stopping or the like, it is possible to prevent ignition or the like due to overheating of the friction braking member.

In addition, the trailer side pulled by the tractor without having a driving source of a vehicle such as an engine need only be provided with the minimum necessary components of pressure detection means, temperature detection means, and transmission means. Power consumption can be minimized. Further, since a pressure fluctuation judging means, a time measuring means, a temperature increase rate increase judging means and an overheat judging means are provided on the tractor side to select and trail one trailer from a plurality of trailers, these means are constituted. It is not necessary to provide expensive electronic components individually for a plurality of trailers, and the overall cost can be reduced.

  According to the present invention, it is possible to detect at an early stage that the temperature of the frictional braking member suddenly rises in a short time and reaches an overheated state due to a defect in the compressed air supply path.

It is a perspective view which shows typically the trailer and tractor by which the overheat determination apparatus and overheat warning apparatus of this embodiment are mounted. It is a block diagram which shows typically an overheat determination apparatus and an overheat warning apparatus. It is a disassembled perspective view of a drum brake. It is an assembly perspective view of a drum brake. It is a front view showing an axle tube, right and left tires, and left and right drum brakes. It is a side view which shows a brake chamber. It is a figure which shows the relationship between the temperature of each part and elapsed time in a start stop pattern. It is a figure which shows the relationship between the temperature of each part in a brake dragging state, and elapsed time. It is a flowchart which shows an overheat determination process. It is a flowchart which shows an overheat determination process.

  An embodiment of the present invention will be described with reference to the drawings.

  In the present embodiment, as shown in FIGS. 1 and 2, an example in which an overheat determination device 10 and an overheat notification device 20 are provided in a vehicle 1 including a tractor 2 and a trailer 3 pulled by the tractor 2 will be described. To do. Moreover, the example of the drum brake 30 shown in FIGS. 3-5 is demonstrated as a brake device used as the determination object of the overheat determination apparatus 10. FIG. The drum brake 30 is provided on each of the left and right sides of the axle shaft 50. However, since the left and right drum brakes 30 have the same configuration, only one of them will be described in the following description, and the other description will be omitted.

  As shown in FIGS. 3 to 5, the drum brake 30 includes a brake shoe unit 31, a brake drum 32 as a rotating member, a dust cover 33, an anchor pin bracket 34, a cam bracket 35, and the like.

  The anchor pin bracket 34 and the cam bracket 35 are integrally provided at the outer end in the vehicle width direction of the axle tube 51 that is supported on the vehicle body side of the trailer 3 and extends in the vehicle width direction. The axle shaft 50 (axle) extending integrally from the outer end of the axle tube 51 supports the wheel (brake drum 32) of the wheel in a freely rotatable manner. The anchor pin bracket 34 extends and protrudes in one direction intersecting the axis of the axle tube 51, and the cam bracket 35 extends and projects in the other direction opposite to the anchor pin bracket 34.

  The brake shoe unit 31 includes a pair of brake shoes 36, a lining 37 as a friction braking member fixed to the outer peripheral surface of each brake shoe 36, a spring 38, and the like. One end of each brake shoe 36 is rotatably connected to an anchor pin 39 of the anchor pin bracket 34, and a spring 38 connects the other end of the brake shoe 36. During normal times (when the brake is not operated), the pair of brake shoes 36 are urged by springs 38 to the non-operating positions that swing inward. A cam 40 rotatably supported by the cam bracket 35 is disposed between the other ends of the pair of brake shoes 36. The rotating shaft 41 of the cam 40 is rotationally driven by a brake chamber 54 described later. As the cam 40 rotates, the outer surface of the cam 40 contacts the roller at the other end of the brake shoe 36 and separates the other end, thereby expanding the brake shoe 36.

  The brake drum 32 is disposed so as to cover the brake shoe 36 from the outside in the vehicle width direction, and is fixed to the outer end portion of the axle shaft 50 in the vehicle width direction. That is, the brake drum 32 is rotatable with respect to the anchor pin bracket 34. A tire 53 (wheel) is attached to the axle shaft 50 via a wheel 52. The brake drum 32 is coupled to the wheel 52 and rotates integrally with the wheel 52. When the brake shoe 36 is expanded, the lining 37 fixed to the outer peripheral surface of the brake shoe 36 comes into sliding contact with the inner peripheral surface 32a of the brake drum 32, and a braking force acts on the rotating axle shaft 50 (tire 53).

  The dust cover 33 covers an internal space surrounded by the brake drum 32 (a space in which the brake shoe unit 31 is disposed) from the inner side in the vehicle width direction, and is fixed to the anchor pin bracket 34. The dust cover 33 prevents intrusion of dust, water or the like inward in the vehicle width direction from the brake shoe unit 31.

  A brake chamber 54 is fixed to an intermediate portion of the axle tube 51. The brake chamber 54 is supplied with compressed air from a relay valve 19 (shown in FIG. 1) as air supply means. The relay valve 19 has an inlet (not shown) through which compressed air flows from an air tank (not shown) and an outlet (not shown) that supplies the compressed air flowing from the inlet to the brake chamber 54. The relay valve 19 receives a brake pressure signal corresponding to the depression of a brake pedal (not shown) that is depressed by the driver of the tractor 2, and the compressed air flowing from the air tank is converted into a pressure corresponding to the received brake pressure signal. To the brake chamber 54. The outlet of the relay valve 19 is provided with a pressure sensor 12 (shown in FIG. 1) as pressure detecting means for detecting the pressure of the compressed air supplied to the brake chamber 54 every predetermined time. Note that the pressure sensor 12 may be provided at a place other than the outlet of the relay valve 19, for example, in an air supply conduit from the relay valve 19 to the brake device.

  The brake chamber 54 rotates the rotating shaft 41 of the cam 40 via a link member with a braking pressure (brake pressure) corresponding to the pressure of the compressed air supplied from the relay valve 19. As a result, the lining 37 of the brake shoe 36 is pressed against the brake drum 32 with a pressing force corresponding to the brake pressure input by the driver, and the braking force acts on the axle shaft 50 (tire 53).

  The outer end portion of the axle tube 51 in the vehicle width direction, the brake shoe 36 to which the lining 37 is fixed, the anchor pin bracket 34 that is fixed to the vehicle body side and supports the brake shoe 36 in a swingable manner, and the outer side of the axle tube 51 in the vehicle width direction. The dust cover 33 that is fixed to the end portion and the vehicle body side in the vehicle width direction and is fixed to the vehicle body side is a part or part that is attached to the vehicle body side in the vicinity of the lining 37. In the present embodiment, a temperature sensor 11 (for example, a thermocouple) as temperature detecting means is fixed to the anchor pin bracket 34 among these parts or portions. The electric wire 13 of the temperature sensor 11 is inserted through the insertion hole 14 formed in the dust cover 33 and extends inward in the vehicle width direction. The temperature sensor 11 detects the surface temperature of the anchor pin bracket 34 as the ambient temperature of the lining 37. The part or part to which the temperature sensor 11 is attached may be a part or part on the vehicle body side that can detect the ambient temperature of the lining 37. For example, the outer surface 51a or the brake shoe at the outer end in the vehicle width direction of the axle tube 51 is used. 36, dust cover 33, cam bracket 35, or the like.

  As shown in FIG. 2, the overheat determination device 10 includes the temperature sensor 11, the pressure sensor 12, a measurement unit 16, a transmitter 17 as a transmission unit, a receiver 18 as a reception unit, and a control unit. 15. Among these, the temperature sensor 11, the pressure sensor 12, the measuring unit 16, and the transmitter 17 are provided in the trailer 3. The control unit 15 functions as pressure fluctuation determination means, time measurement means, temperature rise determination means, second time measurement means, temperature increase rate increase determination means, third time measurement means, and overheat determination means. The sensors 11, 12 and the measuring unit 16 and the measuring unit 16 and the transmitter 17 are connected by signal lines, and the transmitter 17 is fixed to the vehicle body side of the front end portion of the trailer 3. .

  The overheat alarm device 20 includes an overheat determination device 10 and a display unit 22 and a sound output unit 23 as notification means. The receiver 18, the control unit 15, the display unit 22, and the audio output unit 23 constitute a unitized alarm 21 and are provided in the vehicle interior of the tractor 2. The control unit 15 includes an internal memory (not shown), an internal timer (not shown), and the like.

  The temperature sensor 11 and the pressure sensor 12 detect the detected temperature T (ambient temperature of the lining 37) and the detected pressure P (brake pressure by compressed air), respectively, and output them to the measuring unit 16 at predetermined time intervals. . The measurement unit 16 sequentially converts the analog signals input from the sensors 11 and 12 into digital signals and outputs the digital signals to the transmitter 17. The transmitter 17 that has received the digital signal from the measurement unit 16 wirelessly transmits the signal. That is, the signals transmitted by the transmitter 17 are a wireless signal indicating the detected temperature T of the temperature sensor 11 and a wireless signal indicating the detected pressure P of the pressure sensor 12.

  As shown in FIG. 5, the measuring unit 16 is fixed to the upper surface of the axle tube 51 having a rectangular cross section. The mounting location of the measuring unit 16 is not particularly limited, and may be fixed to the front surface or the rear surface of the axle tube 51 as shown by a two-dot chain line in FIG. It may be fixed in place.

  The receiver 18 receives a radio signal from the transmitter 17 and outputs it to the control unit 15. The control unit 15 sequentially stores the detected temperature T and the detected pressure P input as digital signals via the receiver 18 in the internal memory. Note that unnecessary data already used among the detected temperature T and the detected pressure P stored in the internal memory may be appropriately deleted.

  The control unit 15 determines whether or not the lining 37 is in an overheated state according to the following determination criteria.

  The first determination criterion is to determine that the lining 37 is in an overheated state when the latest detected temperature T is equal to or higher than a predetermined reference determination temperature T1. The reference determination temperature T1 is an ambient temperature when the lining 37 is heated to a temperature at which the possibility of ignition is recognized, and is stored in advance in the internal memory.

  The second criterion is that when the time during which the rate of increase of the detected temperature T continues to increase (temperature increase rate increase duration) reaches a predetermined reference time (second reference time), the lining 37 Is determined to be in an overheated state. Specifically, from the latest detection temperature Tn, the previous detection temperature Tn-1, the previous detection temperature Tn-2, and the temperature detection time interval ΔS, the previous temperature increase rate ΔTn-1 / ΔS = (Tn− 1−Tn−2) / ΔS and the current temperature increase rate ΔTn / ΔS = (Tn−Tn−1) / ΔS are calculated, and when ΔTn / ΔS> ΔTn−1 / ΔS, the temperature increase rate increases. It is determined that the lining 37 is in an overheated state when the temperature rise rate increase duration time is measured by the second internal timer and the temperature rise rate increase duration time reaches the second reference time. judge. The second reference time is the duration of the temperature increase rate increase state of the ambient temperature required for the lining 37 to rise to a temperature at which the possibility of ignition is recognized, and is stored in advance in the internal memory.

  The third criterion is that the lining 37 is in an overheated state when the time during which the detected temperature T continues to rise (temperature rise duration) reaches a predetermined reference time (third reference time). It is determined. Specifically, the latest detected temperature Tn and the previous detected temperature Tn-1 are compared, and when Tn> Tn-1, it is determined that the temperature is rising, and the temperature rises by the third internal timer. The duration is measured, and when the temperature rise duration reaches the third reference time, it is determined that the lining 37 is in an overheated state. The third reference time is a duration time of the temperature rise state of the ambient temperature required until the lining 37 is heated to a temperature at which the possibility of ignition is recognized, and is stored in advance in the internal memory. The third reference time is set to be longer (for example, about 2 to 3 times) than the second reference time.

  The fourth criterion is to determine whether the detected pressure P is a positive pressure and a positive pressure stable state in which the fluctuation amount of the detected pressure P per predetermined time is maintained within a predetermined range. When the continuation time reaches a predetermined reference time (first reference time), it is determined whether or not the rate of increase in the detected temperature T has increased, and the rate of increase in the detected temperature T has increased. Sometimes it is determined that the lining 37 is in an overheated state. Specifically, the latest detected pressure Pn is a positive pressure (Pn> 0), and the difference ΔP = | Pn−Pn−1 | between the latest detected pressure Pn and the previous detected pressure Pn−1 is a predetermined value. When the pressure is equal to or lower than P0 (ΔP ≦ P0), it is determined that the positive pressure is stable, the positive pressure stable state duration is measured by the first internal timer, and the positive pressure stable state duration is the first time. When the reference time is reached, from the latest detected temperature Tn, the previous detected temperature Tn-1, the previous detected temperature Tn-2, and the temperature detection time interval ΔS, the previous temperature rise rate ΔTn-1 / ΔS = (Tn-1−Tn-2) / ΔS and the current temperature rise rate ΔTn / ΔS = (Tn−Tn−1) / ΔS are calculated, and when ΔTn / ΔS> ΔTn−1 / ΔS, the temperature It is determined that the rate of increase is increasing, and it is determined that the lining 37 is in an overheated state. The predetermined range (predetermined pressure P0) used as a reference when determining whether or not the positive pressure is stable is the fluctuation range (detected by the driver) of the pressure detected by the pressure sensor 12 when the driver is not performing a brake operation. This is a narrow range in which it can be assumed that the brake operation is not performed, and is stored in the internal memory in advance. The first reference time is the duration of the positive pressure stable state of the compressed air required until the lining 37 is heated to a temperature at which the possibility of ignition is recognized, and is stored in advance in the internal memory. When the positive pressure stable state continuation time reaches the first reference time, it may be determined that the lining 37 is in an overheated state without determining whether or not the temperature increase rate is increasing. In addition, when the positive pressure stable state continuation time reaches the first reference time, it is determined whether or not the temperature is rising, and when the temperature is rising, the lining 37 is determined to be overheated. Also good.

  When the control unit 15 determines that the lining 37 is in an overheated state, the control unit 15 displays an image for informing the determination result on the display unit 22, and outputs an audio or alarm sound (for example, a buzzer sound) for informing the determination result. Output from the output unit 23. The control unit 15 can be provided on the trailer 3 side. In this case, information indicating the determination result of the control unit 15 may be transmitted to the tractor 2 side by a radio signal. Further, an indicator lamp such as an LED may be provided in addition to or instead of the display unit 22 and the predetermined indicator lamp may be turned on when it is determined that the lining 37 is in an overheated state.

  Next, the temporal changes in the temperature of the lining 37 and the ambient temperature during normal travel where the brake device functions normally, and the temporal changes in the temperature of the lining 37 and the ambient temperature in the brake drag state will be described.

  FIG. 7 shows that the vehicle is accelerated to a predetermined vehicle speed Va during normal driving when the brake device functions normally, and the vehicle is stopped by applying a normal appropriate predetermined brake pressure. The surface temperature of the lining 37 and the anchor pin bracket 34 (indicated as an anchor pin in the figure) when the starting stop pattern of re-acceleration up to the vehicle speed Va and applying the predetermined brake pressure again to stop the vehicle is repeated. An example of temporal changes in the surface temperature and the back surface temperature of the brake shoe 36 (the surface temperature of the inner peripheral surface on the back side of the sliding surface with the brake drum 32) is shown.

  As shown in FIG. 7, the surface temperature of the lining 37 rises to around Trh ° C. in about 100 minutes, and then this temperature is maintained. The rear surface temperature of the brake shoe 36 rises to around Tsh ° C. (Tsh <Trh) in about 100 minutes, and then this temperature is maintained. The surface temperature of the anchor pin bracket 34 rises to around Tah ° C. (Tah <Tsh) in about 150 minutes, and then this temperature is maintained. That is, in this example, the upper limit temperatures of the lining 37, the brake shoe 36, and the anchor pin bracket 34 during normal vehicle travel are Trh ° C., Tsh ° C., and Tah ° C., respectively, and the brake shoe 36 reaches Tsh ° C. When the anchor pin bracket 34 reaches Tah ° C., it can be determined that the lining 37 has reached Trh ° C. and has been overheated. In the present embodiment in which the surface temperature of the anchor pin bracket 34 is detected, the determination reference temperature T1 is set to Tah ° C., and the lining 37 is overheated when the surface temperature of the anchor pin bracket 34 reaches Tah ° C. Is determined. When detecting the temperature of other parts and parts such as the brake shoe 36, the dust cover 33, and the outer surface 51a of the axle tube 51 as the ambient temperature of the lining 37, the reference temperature may be changed and set (for example, In the case of the brake shoe 36, Tsh ° C as described above).

  FIG. 8 shows a state where the vehicle running at a constant speed Vb is constantly supplied with the compressed air due to a failure of the compressed air supply function to the brake device, and the lining 37 is constantly pressed against the brake drum 32 ( An example of temporal changes in the surface temperature of the lining 37, the surface temperature of the anchor pin bracket 34, and the back surface temperature of the brake shoe 36 in the brake drag state) is shown.

  As shown in FIG. 8, in a brake drag state in which compressed air is constantly supplied, the lining 37 reaches Trh ° C. 500 seconds after the start of dragging. That is, the lining 37 in the brake drag state reaches an overheated state in an extremely short time as compared with the normal time shown in FIG. On the other hand, the temperatures of the brake shoe 36 and the anchor pin bracket 34 after 500 seconds are Ts ° C. and about Ta ° C., respectively, which are lower than the upper limit temperature (Ts <Tsh, Ta <Tah). Therefore, when the brake dragging state occurs and the temperature of the lining 37 suddenly rises in a short time, the lining 37 is overheated simply by comparing the ambient temperature of the lining 37 and the judgment reference temperature (upper limit temperature). It can be seen that it cannot be determined.

  Next, the overheat determination process executed by the control unit 15 will be described based on the flowcharts of FIGS. 9 and 10. For example, the control unit 15 repeatedly performs the overheat determination process at predetermined time intervals while the engine of the tractor 2 is being driven. Note that the process of step S3 is a process according to the first determination criterion, the processes of steps S5 to S10 are a process according to the second determination criterion, and the processes of steps S11 to S15 are: This is processing according to the third determination criterion, and the processing of steps S16 to S21 is processing according to the fourth determination criterion.

  When the overheat determination process is started, first, the detected temperature (the ambient temperature of the lining 37) T of the temperature sensor 11 is acquired (step S1), and the detected pressure (brake pressure) P of the pressure sensor 12 is acquired (step S2).

  Next, it is determined whether or not the ambient temperature T is equal to or higher than the reference determination temperature T1 (step S3). If the ambient temperature T is equal to or higher than the reference determination temperature (step S3: YES), it is determined that the lining 37 is in an overheated state. (Step S4). When it is determined that the lining 37 is in an overheated state, the present process is terminated, and the subsequent overheat determination process is not repeatedly executed, but the determination is held.

  When it is determined in step S3 that the ambient temperature T is lower than the reference determination temperature T1 (step S3: NO), the latest detection temperature Tn, the previous detection temperature Tn-1, the previous detection temperature Tn-2, and the temperature From the detection time interval ΔS, the previous temperature increase rate ΔTn−1 / ΔS = (Tn−1−Tn−2) / ΔS and the current temperature increase rate ΔTn / ΔS = (Tn−Tn−1) / ΔS Is calculated (step S5), and it is determined whether or not the temperature increase rate increase state (ΔTn / ΔS> ΔTn−1 / ΔS) is satisfied (step S6). Since the previous temperature increase rate ΔTn−1 / ΔS is a value already calculated at the time of the previous process, the temperature increase rate calculated at each process is stored in the internal memory, and the previous temperature increase The rate may be read from the internal memory without being calculated again.

  If it is determined in step S6 that the temperature increase rate has been increased (step S6: YES), whether or not the second internal timer has already started measuring the temperature increase rate increase duration (whether or not the time is being measured). ) Is determined (step S7). If it is not timed (step S7: NO), the time measurement by the second internal timer is started (step S8), and then the process proceeds to step S9. On the other hand, when the time is being measured (step S7: YES), the process directly proceeds to step S9.

  In step S9, it is determined whether or not the time of the temperature increase rate increase duration by the second internal timer has reached the second reference time, and if the second reference time has been reached (step S9: YES). It is determined that the lining 37 is in an overheated state (step S4). On the other hand, if it is less than the second reference time (step S9: NO), the process proceeds to step S11.

  If it is determined in step S6 that the temperature increase rate is not increased (step S6: NO), the second internal timer is reset (stopping timing and clearing the count value) (step S10), and then the process proceeds to step S11. .

  In step S11, the latest detected temperature Tn is compared with the previous detected temperature Tn-1, and it is determined whether or not the temperature rises (Tn> Tn-1).

  If it is determined in step S11 that the temperature is rising (step S11: YES), it is determined whether or not the time of the temperature increase duration by the third internal timer has already started (whether or not the time is being measured). (Step S12). If it is not timed (step S12: NO), the time measurement by the third internal timer is started (step S13), and then the process proceeds to step S14. On the other hand, when the time is being measured (step S12: YES), the process directly proceeds to step S14.

  In step S14, it is determined whether or not the temperature rise continuation time measured by the third internal timer has reached the third reference time. If the third reference time has been reached (step S14: YES), the lining is performed. It is determined that 37 is in an overheated state (step S4). On the other hand, if it is less than the third reference time (step S14: NO), the process proceeds to step S16.

  In step S16, the latest detected pressure Pn is a positive pressure (Pn> 0), and the difference ΔP = | Pn−Pn−1 | between the latest detected pressure Pn and the previous detected pressure Pn−1 is a predetermined pressure. It is determined whether or not the positive pressure stable state is equal to or less than P0 (ΔP ≦ P0).

  If it is determined in step S16 that the positive pressure is stable (step S16: YES), whether or not the positive pressure stable state duration time by the first internal timer has already been started (whether or not time is being measured). Is determined (step S17). If it is not timed (step S17: NO), after the time measurement by the first internal timer is started (step S18), the process proceeds to step S19. On the other hand, when the time is being measured (step S17: YES), the process directly proceeds to step S19.

  In step S19, it is determined whether or not the time of the positive pressure stable state duration by the first internal timer has reached the first reference time, and when the first reference time has been reached (step S19: YES). The process proceeds to step S20.

  In step S20, using the previous temperature increase rate ΔTn-1 / ΔS calculated in step S5 and the current temperature increase rate ΔTn / ΔS, the temperature increase rate increasing state (ΔTn / ΔS> ΔTn) as in step S6. −1 / ΔS), and if it is determined that the temperature increase rate is in an increasing state (step S20: YES), it is determined that the lining 37 is in an overheated state (step S4).

  In step S16, when it is determined that the positive pressure is not stable (step S16: NO), the first internal timer is reset (timekeeping stop and count value clear) (step S21), and then the process ends. . Further, when it is determined in step S19 that the time of the positive pressure stable state duration by the first internal timer has not reached the first reference time (step S19: NO), and in step 20, the temperature increase rate increases. Even when it is determined that it is not in a state (step S20: NO), this process is terminated.

  According to this embodiment, in a state where the relay valve 19 functions properly, that is, in a state where the relay valve 19 supplies compressed air having an appropriate pressure to the brake device in accordance with the brake pressure signal, the driver performs a brake operation. When there is no brake pedal (when the brake pedal is not depressed), the relay valve 19 does not supply compressed air to the brake device, the detected pressure P of the pressure sensor 12 is maintained at zero, and the lining 37 does not slide against the brake drum 32. The detected temperature T of the temperature sensor 11 does not rise from the ambient temperature. Therefore, the control unit 15 has the detected temperature T lower than the determination reference temperature (step S3: NO), is not in the temperature listing rate increasing state (step S6: NO), and is not in the temperature rising state (step S11: NO). It is determined that the positive pressure is not stable, and it is determined that the lining 37 is not overheated.

  In addition, when the driver depresses the brake pedal with an appropriate brake operation in order to stop or decelerate the vehicle in a state where the relay valve 19 is functioning properly, the relay valve 19 is compressed with a pressure corresponding to the brake pressure signal. Supply air to the brake system. In this state, the detected temperature T does not reach the determination reference temperature (step S3: NO), and the time of the temperature increase rate increase duration by the second internal timer does not reach the second reference time. (Step S9: NO), the measurement of the temperature rise duration time by the third internal timer does not reach the third reference time (Step S14: NO), and the compressed air supplied to the brake device The pressure greatly fluctuates, and the fluctuation amount of the detected pressure P of the pressure sensor 12 exceeds the predetermined range (step S16: NO), or continues for the first reference time or longer even if the fluctuation amount of the detected pressure P is maintained within the predetermined range. (Step S19: NO). For this reason, the control unit 15 determines that the lining 37 is not overheated.

  In addition, in a state where the relay valve 19 is functioning properly, a driver of a vehicle traveling on a slope continuously repeats a sudden brake operation and a release operation at a short time interval, or continues a weak brake operation. When the detected temperature T reaches the determination reference temperature (step S3: YES) due to an improper brake operation such as performing, or when the temperature increase rate increasing state continues for the second reference time or more (step) S9: YES) or when the temperature rise state continues for the third reference time or longer (step S13: YES), the control unit 15 determines that the lining 37 is in an overheated state, and displays the determination result on the display unit 22. This is notified to the driver by means of an image, a voice from the voice output unit 23, and the like. Therefore, the driver can recognize early that the lining 37 is in an overheated state due to an inappropriate brake operation by the driver.

  On the other hand, although the relay valve 19 is defective and the driver releases the brake operation, the constant pressure compressed air is continuously supplied to the brake device, and the lining 37 continues to slide on the brake drum 32. When in contact with each other, the detected pressure P is a positive pressure, and the amount of fluctuation every predetermined time is maintained within a predetermined range. Further, when the lining 37 is overheated, the detected temperature T is in a temperature increase rate increasing state. For this reason, the control unit 15 determines that the positive pressure is stable (step S16: YES), starts or continues to count the positive pressure stable state duration by the first internal timer, and the positive pressure stable state duration is reached. When it reaches the first reference time (step S19: YES), it is determined that the temperature increase rate is in an increasing state (step S20: YES), and it is determined that the lining 37 is in an overheated state.

  That is, in a situation where the lining 37 continues to come into sliding contact with the brake drum 32 due to a defect in the relay valve 19 and the temperature of the lining 37 rapidly rises in a short time, the positive pressure stable state duration is the first reference time. Is reached, it is determined that the lining 37 is in an overheated state. For this reason, it is possible to detect early and reliably that the temperature of the lining 37 suddenly rises in a short time due to a defect of the relay valve 19 and reaches an overheated state.

  Further, the driver in the passenger compartment of the tractor 2 may recognize early that the lining 37 is in an overheated state or is extremely likely to be in an overheated state by notification from the display unit 22 or the audio output unit 23. In addition, it is possible to prevent ignition due to overheating of the lining 37 by stopping the vehicle.

  Further, on the trailer 3 side to be pulled by the tractor 2 without having a vehicle driving source such as an engine, only a minimum necessary configuration of a temperature sensor 11, a pressure sensor 12, a measuring unit 16, and a transmitter 17 is provided. Therefore, power consumption on the trailer 3 side can be minimized. Furthermore, since the control unit 15 is provided on the tractor 2 side to select and trail one trailer from a plurality of trailers, it is not necessary to individually provide the control units 15 made of expensive electronic components on the plurality of trailers. The cost can be reduced as a whole.

  In the above embodiment, an example in which the present invention is applied to the drum brake 30 has been described. However, the present invention can also be applied to other types of brake devices such as a disbrake. Moreover, although the example which applied this invention to the vehicle which consists of a tractor and a trailer was shown in the said embodiment, this invention is applicable also to other types of vehicles, such as a truck.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Tractor 3 Trailer 10 Overheat determination apparatus 11 Temperature sensor (temperature detection means)
12 Pressure sensor (pressure detection means)
15 Control unit (time measuring means, judging means)
17 Transmitter (Transmission means)
18 Receiver (Receiving means)
19 Relay valve (air supply means)
20 Overheat notification device 22 Display section (notification means)
23 Voice output unit (notification means)
30 Drum brake (brake device)
31 Brake shoe unit 32 Brake drum (rotating member)
33 Dust cover 34 Anchor pin bracket 35 Cam bracket 36 Brake shoe 37 Lining (friction braking member)
40 cam 50 axle shaft 51 axle tube 51a outer surface of axle tube in the vehicle width direction 52 wheel 53 tire (wheel)
54 Brake chamber

Claims (7)

An air supply means for supplying compressed air at a pressure corresponding to the brake pressure signal, and a friction braking member on the vehicle body side to slide on the wheel-side rotating member with a pressing force corresponding to the pressure of the compressed air supplied from the air supply means. A brake device that brakes the wheel in contact with the overheat determination device in a brake system,
Pressure detection means for detecting the pressure of compressed air supplied from the air supply means to the brake device every predetermined time;
Pressure fluctuation determination means for determining whether or not the pressure detected by the pressure detection means is a positive pressure and a positive pressure stable state in which the amount of pressure fluctuation every predetermined time is maintained within a predetermined range;
Time measuring means for measuring the time during which the determination result by the pressure fluctuation determining means is continuously in the positive pressure stable state;
An overheat determination device for a brake device, comprising: an overheat determination unit that determines that the friction braking member is in an overheated state when a time counted by the time measuring unit reaches a predetermined reference time. The overheat determination device according to claim 1,
The air supply means includes a relay valve having an inflow port through which compressed air flows and an outflow port for supplying compressed air flowing in from the inflow port to the brake device at a pressure corresponding to the brake pressure signal. Including
The said pressure detection means is provided in the outflow port of the said relay valve. The heating determination apparatus of the brake device characterized by the above-mentioned. The overheat determination device according to claim 1 or 2,
A temperature detecting means which is attached to the vehicle body side in the vicinity of the friction braking member and detects the ambient temperature of the friction braking member every predetermined time;
Temperature increase rate increase determination means for determining whether the temperature increase rate is increasing based on the ambient temperature detected by the temperature detection means for each predetermined time. ,
The overheat determining means is when the time measured by the time measuring means reaches the predetermined reference time, and when the temperature increase rate increase determining means determines that the temperature increase rate increase state is present, An overheat determination device for a brake device, wherein the friction braking member is determined to be in an overheated state. The overheat determination device according to claim 3,
A second timing unit that counts the time during which the determination result by the temperature increase rate increase determination unit continuously becomes the temperature increase rate increase state;
The overheat determining means determines that the friction braking member is in an overheated state when the time counted by the second time measuring means reaches a predetermined second reference time. Overheat determination device. The overheat determination device according to claim 3 or 4, wherein
A temperature rise determination means for judging whether or not the ambient temperature is rising based on the ambient temperature detected by the temperature detection means every predetermined time; and
A third timing unit that counts a time during which the determination result by the temperature increase determination unit is continuously in the temperature increase state;
The overheat determining means determines that the friction braking member is in an overheated state when the time counted by the third time measuring means reaches a predetermined third reference time. Overheat determination device. The overheat determination device according to any one of claims 3 to 5,
The brake device is a drum brake that slidably contacts a lining as a friction braking member with a brake drum as the rotating member,
The temperature detecting means includes a brake shoe to which the lining is fixed, an anchor pin bracket that is fixed to the vehicle body and supports the brake shoe in a swingable manner, and an axle tube that is fixed to the vehicle body and rotatably supports the wheel. Or an overheat determination device for a brake device, wherein the overheat determination device is attached to a dust cover that is fixed to a vehicle body and covers an inner side in the vehicle width direction of the lining. An air supply means for supplying compressed air at a pressure corresponding to the brake pressure signal, and a friction braking member on the vehicle body side to slide on the wheel-side rotating member with a pressing force corresponding to the pressure of the compressed air supplied from the air supply means. The brake device that brakes the wheel in contact is an overheat warning device in a brake system provided in a trailer pulled by a tractor,
The overheat determination device according to any one of claims 3 to 6, and a notification means,
The overheat determination device includes a transmission unit that transmits pressure information indicating the pressure detected by the pressure detection unit and a temperature information indicating the ambient temperature detected by the temperature detection unit, and a wireless signal transmitted by the transmission unit. Receiving means for receiving a signal,
The pressure detection means, the temperature detection means, and the transmission means are provided on a trailer pulled by a tractor,
The pressure fluctuation determining means, the time measuring means, the temperature increase rate increase determining means, the overheat determining means, and the receiving means are provided in the tractor,
The reception means outputs the received pressure information to the pressure fluctuation determination means, and outputs the received temperature information to the temperature increase rate increase determination means.
The informing means is provided in a passenger compartment of the tractor, and when the overheat determining means determines that the friction braking member is in an overheated state, the informing means is informed to a driver in the passenger compartment. Equipment overheat alarm device.

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