Working machinery

Abstract

This disclosure provides a work machine that can reduce noise at the ear level of the operator, regardless of the operator's physique in the driver's cab. [Solution] The work machine 1 comprises a driver's cab 130, a Helmholtz resonator 140 installed in the driver's cab 130, and a support mechanism 150 that supports the Helmholtz resonator 140 in an adjustable position.

Description

Technical Field

[0001] The present disclosure relates to a work machine.

Background Art

[0002] Conventionally, an invention related to a device for reducing mainly low-frequency sounds, that is, stuffy sounds, generated in a cab due to rotational vibration of an engine or the like during vehicle travel is known (see Patent Document 1 below).

[0003] The cab of the work vehicle described in Patent Document 1 includes a resonance pipe or a resonance box that resonates at the frequency of the cavity resonance at a position where the sound pressure is high when the cavity resonance occurs. Patent Document 1 states that according to the above cab, since the cavity resonance frequency can be shifted by an acoustic dynamic vibration absorption effect, an increase in noise caused by cavity resonance can be avoided without a significant change in the wall shape, and the stuffy sound can be reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional cab of the work vehicle described in Patent Document 1, a resonance pipe or a resonance box, which is a Helmholtz resonator, is fixed outside or inside the wall surface of the cab, which is the driver's cab of the work vehicle. The sound pressure distribution inside the driver's cab changes according to the installation position of the Helmholtz resonator. Also, the position of the operator's ear when boarding the driver's cab changes according to the operator's physique. Therefore, in the conventional technology described in Patent Document 1, depending on the installation position of the Helmholtz resonator and the operator's physique, there is a risk that the noise increases at the position of the operator's ear.

[0006] This disclosure provides a work machine that can reduce noise at the operator's ear level, regardless of the operator's physique in the cab. [Means for solving the problem]

[0007] One aspect of the present disclosure provides a working machine comprising: a driver's cab; a Helmholtz resonator installed in the driver's cab; and a support mechanism for supporting the Helmholtz resonator in an adjustable position. [Effects of the Invention]

[0008] According to the above-described aspect of this disclosure, it is possible to provide a work machine that can reduce noise at the operator's ear level, regardless of the operator's physique in the cab. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing an embodiment of the work machine relating to this disclosure. [Figure 2] Figure 1 is a schematic perspective view showing an example of a driver's cab in a working machine. [Figure 3] Figure 2 is an explanatory diagram of the Helmholtz resonator installed in the driver's cab. [Figure 4] Figure 1 is a functional block diagram of the control device mounted on the work machine. [Figure 5] This is a sound pressure map showing an example of the sound pressure distribution in each cross-section of the driver's cab in Figure 2. [Figure 6] This is a sound pressure map showing an example of the sound pressure distribution in each cross-section of the driver's cab in Figure 2. [Figure 7] This is a flowchart illustrating an example of processing performed by each part of the control device shown in Figure 4. [Figure 8] This is a flowchart illustrating an example of processing performed by each part of the control device shown in Figure 4. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the work machine relating to this disclosure will be described with reference to the drawings.

[0011] The embodiments described below are illustrative and not limiting to the invention. Not all features and combinations thereof in the embodiments of this disclosure are necessarily essential to the invention. In each drawing, the same or corresponding components are denoted by the same or corresponding reference numerals, and redundant descriptions may be omitted.

[0012] Figure 1 is a block diagram showing an embodiment of the work machine according to this disclosure. Figure 2 is a schematic perspective view showing an example of the operator's cab 130 of the work machine 1 according to this embodiment.

[0013] The most distinctive feature of the work machine 1 of this embodiment, as shown in Figure 2, is that it comprises an operator's cab 130, a Helmholtz resonator 140 installed in the operator's cab 130, and a support mechanism 150 that supports the Helmholtz resonator 140 in a position-adjustable manner.

[0014] The specific configuration of the work machine 1 of this embodiment will be described in detail below.

[0015] Work machinery 1 includes, for example, construction machinery, transport machinery, road machinery, and application machinery. Construction machinery includes, for example, hydraulic excavators, crawler cranes, tower cranes, aerial work platforms, wheel loaders, bulldozers, etc. Transport machinery includes, for example, dump trucks, forklifts, etc. Road machinery includes, for example, asphalt finishers, road rollers, etc. Application machinery includes, for example, forestry machinery, metal recycling machinery, demolition machinery, etc.

[0016] The working machine 1, for example as shown in Figure 1, includes an engine 101, a cooling fan 102, a hydraulic pump 103, a control valve 104, a hydraulic actuator 105, a power supply unit 106, a moving device 107, a sensor 108, and an operating device 109. The working machine 1 also includes, for example, an output device 110 and a control device 120.

[0017] The engine 101 is an internal combustion engine such as a diesel engine, for example, and is a power source that generates power to drive the hydraulic pump 103 or rotate the generator of the power supply device 106. Further, the working machine 1 may be provided with an electric motor as a power source instead of the engine 101 or together with the engine 101.

[0018] The cooling fan 102 is rotated, for example, by driving a motor with electric power supplied from the power supply device 106. The rotation of the cooling fan 102 is controlled by the control device 120, for example, and blows air to the radiator for cooling water for cooling a power source such as the engine 101.

[0019] The hydraulic pump 103 is driven by a power source such as the engine 101, sucks hydraulic oil stored in the hydraulic oil tank from the suction port, and discharges it from the discharge port. The hydraulic pump 103 is a variable displacement type hydraulic pump, for example, and the discharge amount of the hydraulic oil is controlled by controlling the tilt angle by the control device 120.

[0020] The control valve 104 supplies the hydraulic oil discharged from the hydraulic pump 103 to the hydraulic actuator 105 at a predetermined flow rate and direction based on the operation of the operation device 109 by the operator of the working machine 1 and the control command from the control device 120.

[0021] The hydraulic actuator 105 includes, for example, a travel hydraulic motor when the working machine 1 has a lower traveling body, a swing hydraulic motor when the working machine 1 has an upper swing body, and the like. Further, the hydraulic actuator 105 includes, for example, a hydraulic cylinder for driving an attachment when the working machine 1 is a hydraulic excavator or an application machine, a winch when the working machine 1 is a crane, and the like.

[0022] The power supply unit 106 includes, for example, a generator rotated by the engine 101. Alternatively, the power supply unit 106 may consist of multiple secondary batteries. The power supply unit 106 supplies power to various parts of the work machine 1, including, for example, a cooling fan 102, a moving device 107, a sensor 108, an operating device 109, an output device 110, and a control device 120.

[0023] The moving device 107 is provided on the support mechanism 150 shown in Figure 2 and moves the Helmholtz resonator 140. Specifically, the moving device 107 includes, for example, a plurality of motors and a plurality of gears that drive various parts of the support mechanism 150. The moving device 107 is controlled, for example, by the control device 120 and automatically moves the Helmholtz resonator 140, which is supported by the support mechanism 150, in the forward / backward, left / right, and up / down directions as viewed from the operator seated in the driver's seat 137 of the driver's cab 130. Note that if the operator manually moves the Helmholtz resonator 140 supported by the support mechanism 150, the installation of the moving device 107 may be omitted.

[0024] Sensor 108 includes, for example, internal sensors and external sensors. Internal sensors include, for example, a camera that detects the position of the ear of an operator seated in a driver's seat 137 installed in the driver's cab 130. Internal sensors may also include a rotational speed sensor that detects the rotational speed of the engine 101, a discharge pressure sensor that detects the discharge pressure of the hydraulic pump 103, a position sensor that detects the position of the Helmholtz resonator 140, and an operation sensor that detects the operation of the operating device 109 by the operator. External sensors include, for example, a LiDAR, camera, millimeter-wave radar, ultrasonic sensor, etc. that detect objects around the work machine 1.

[0025] The operating device 109 includes, for example, operating levers, operating pedals, operating buttons, and an operating panel installed inside the driver's cab 130. The operating device 109 receives, for example, an operation from the operator and outputs a signal to the control device 120 corresponding to the operator's operation.

[0026] The output device 110 includes, for example, an image display device and an audio output device. The image display device may also include an operating device 109 such as a touch panel or operation buttons. The output device 110 is controlled, for example, by the control device 120 and outputs information regarding the installation position of the Helmholtz resonator 140 to notify the operator seated in the driver's seat 137. The output device 110 may also output information regarding objects around the work machine 1 detected by the external sensor 108, or the state of the work machine 1, to notify the operator seated in the driver's seat 137.

[0027] The control device 120 includes, for example, electronic circuits such as a central processing unit (CPU), a field-programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). The control device 120 performs various processes, including the control of each part of the work machine 1, by executing instruction codes stored in memory or by circuit design for special applications. The control device 120 may be a single integrated device or may be multiple devices separated by function.

[0028] The driver's cab 130, also called a cabin or cab, provides a living space for the operator who operates the work machine 1. In this embodiment, the driver's cab 130 is a closed space having, for example, a front wall 131, a rear wall 132, a left side wall 133, a right side wall 134, a ceiling 135, and a floor 136. Transparent windows are provided in the front wall 131, the rear wall 132, the left side wall 133, and the right side wall 134.

[0029] A support mechanism 150 for supporting the Helmholtz resonator 140 is provided on the ceiling 135 of the driver's cab 130. The support mechanism 150 may also be provided on a part other than the ceiling 135 of the driver's cab 130, such as the rear wall 132 or the floor 136 of the driver's cab 130. The floor 136 of the driver's cab 130 is provided with a driver's seat 137 where the operator sits, and operating devices 109 operated by the operator. In the work machine 1 of this embodiment, the front-rear, left-right, and up-down directions are directions as viewed from the operator seated in the driver's seat 137 of the driver's cab 130.

[0030] Figure 3 is an explanatory diagram of the Helmholtz resonator 140 installed in the driver's cab 130 of Figure 2. The Helmholtz resonator 140 is a hollow member having, for example, a container portion 141 and a neck portion 142. The shape of the container portion 141 is not particularly limited and can be a rectangular parallelepiped, cylindrical, or any other three-dimensional shape. The neck portion 142 is formed, for example, as a cylindrical shape with an opening at its tip, and connects the internal space of the container portion 141 to the internal space of the driver's cab 130.

[0031] The resonant frequency f of the Helmholtz resonator 140 is set, for example, according to the frequency of noise inside the operator's cab 130. Specifically, noise may be generated inside the operator's cab 130 due to the engine 101 of the work machine 1, the cooling fan 102, the hydraulic pump 103, etc. By measuring the noise inside the operator's cab 130 in advance, the frequency of the noise with the highest sound pressure can be identified.

[0032] The resonant frequency f of the Helmholtz resonator 140 can be set, for example, to the frequency of the noise with the highest sound pressure inside the driver's cab 130. Specifically, the resonant frequency f of the Helmholtz resonator 140 is determined by the speed of sound c, pi π, the opening area s of the neck portion 142, the volume V of the container portion 141, and the length L of the neck portion 142, as shown in equation (1) in Figure 3. The opening area s of the neck portion 142 is determined by the inner diameter d of the opening in the cylindrical neck portion 142.

[0033] More specifically, let's assume, for example, that the noise frequency with the highest sound pressure inside the driver's cab 130 is 280 Hz. In this case, if the inner diameter d of the neck section 142 is 200 mm and the length L of the neck section 142 is 10 mm, then the volume V of the container section 141 is approximately 0.117 m³. 3 Therefore, if the container section 141 is a rectangular parallelepiped, the height × width × length of the container section 141 can be set to, for example, approximately 300 mm × 550 mm × 711 mm.

[0034] Note that the frequency of the noise with the highest sound pressure inside the driver's cab 130 and the dimensions of the Helmholtz resonator 140 are examples only and are not particularly limited. Also, the volume V of the container section 141 of the Helmholtz resonator 140 may be variable. Specifically, the volume V of the container section 141 may be made variable by configuring a part of the side wall of the container section 141 to be movable using a motor or gear. This makes it possible to vary the resonance frequency f of the Helmholtz resonator 140 according to the frequency of the noise inside the driver's cab 130 in which sound pressure reduction is desired.

[0035] As shown in Figure 2, the support mechanism 150 supports the Helmholtz resonator 140 in an adjustable position. In the example shown in Figure 2, the support mechanism 150 has a pair of front and rear rails 151, left and right rails 152, and up and down rails 153.

[0036] A pair of front and rear rails 151 are fixed to the upper parts of the left wall 133 and right wall 134 of the driver's cab 130 and extend in the front-rear direction. The left and right rails 152 extend in the left-right direction and are supported by the pair of front and rear rails 151 so that they can slide in the front-rear direction, with their left and right ends supported by the right front and rear rail 151 and the left front and rear rail 151, respectively. The up and down rails 153 extend in the up and down direction and have a Helmholtz resonator 140 connected to their lower end, and are connected to the left and right rails 152 so that they can slide in the up and down and left and right directions.

[0037] With this configuration, the operator can manually adjust the installation position of the Helmholtz resonator 140 by, for example, grasping the Helmholtz resonator 140, which is supported by the support mechanism 150, and moving it in the forward / backward, left / right, and up / down directions. Alternatively, the installation position of the Helmholtz resonator 140 can be automatically adjusted by moving the left / right rails 152 in the forward / backward direction relative to the pair of front / rear rails 151, or by moving the up / down rail 153 in the up / down and left / right directions relative to the left / right rails 152, using the moving device 107.

[0038] Figure 4 is a functional block diagram of the control device 120 mounted on the work machine 1 shown in Figure 1. The control device 120 has, for example, an acquisition unit 121, a position determination unit 122, and a guidance output unit 123 as functions to reduce noise at ear level of the operator seated in the driver's seat 137 located inside the driver's cab 130. The control device 120 may also have a position control unit 124 instead of the guidance output unit 123, or together with the guidance output unit 123.

[0039] The various parts of the control device 120 shown in Figure 4 represent the various functions of the control device 120, which are realized, for example, by the CPU of the control device 120 executing a program stored in the memory of the control device 120. The processing performed by each part of the control device 120 shown in Figure 4 will be described later with reference to Figures 7 and 8.

[0040] Figures 5 and 6 are sound pressure maps showing examples of sound pressure distribution in cross-sections along the Va-Va, Vb-Vb, Vc-Vc, VIa-VIa, VIb-VIb, and VIc-VIc lines of the driver's cab 130. In each sound pressure map, darker colors (higher dot density) indicate higher sound pressure, while lighter colors (lower dot density) indicate lower sound pressure. In other words, in each sound pressure map, the black areas represent the areas with the highest sound pressure, and the white areas represent the areas with the lowest sound pressure.

[0041] As shown in the upper left cross-sectional view of Figure 5, the Helmholtz resonator 140 is positioned above the rear of the driver's seat 137 in the front-rear direction of the driver's cab 130, and is located on the rear side of the driver's cab 130, closer to the rear wall 132 than to the front wall 131. Furthermore, as shown in the upper right cross-sectional view of Figure 5, which shows the driver's seat 137 viewed from the rear, the Helmholtz resonator 140 is positioned to the right of the center in the left-right direction of the driver's cab 130, and is located on the right side of the driver's cab 130, closer to the right wall 134 than to the left wall 133.

[0042] On the other hand, the Helmholtz resonator 140 in Figure 6, as shown in the upper left cross-sectional view of Figure 6, is positioned in the front-rear direction of the cab 130, above the front of the driver's seat 137, and is located on the front side of the cab 130, closer to the front wall 131 than to the rear wall 132. Furthermore, the Helmholtz resonator 140 in Figure 6, as shown in the upper right cross-sectional view of Figure 6, which views the driver's seat 137 from the rear, is positioned in the left-right direction of the cab 130, closer to the center than the example shown in the upper right cross-sectional view of Figure 5, and slightly closer to the right side of the center of the cab 130, closer to the right wall 134 than to the left wall 133.

[0043] The sound pressure map in the lower right of Figure 5 shows the sound pressure distribution of noise in the Va-Va cross section in the upper right cross section of Figure 5. Similarly, the sound pressure map in the lower right of Figure 6 shows the sound pressure distribution of noise in the VIa-VIa cross section in the upper right cross section of Figure 6. Comparing these sound pressure maps, it can be seen that placing the Helmholtz resonator 140 in the position shown in Figure 6 reduces the sound pressure at the operator's right ear position RE compared to when it is placed in the position shown in Figure 5.

[0044] The sound pressure map in the lower left of Figure 5 shows the sound pressure distribution of noise in the Vb-Vb cross section in the upper right cross section of Figure 5. Similarly, the sound pressure map in the lower left of Figure 6 shows the sound pressure distribution of noise in the VIb-VIb cross section in the upper right cross section of Figure 6. Comparing these sound pressure maps, it can be seen that placing the Helmholtz resonator 140 in the position shown in Figure 5 slightly reduces the sound pressure at the operator's left ear position LE compared to when it is placed in the position shown in Figure 6.

[0045] The sound pressure map in the lower center of Figure 5 shows the sound pressure distribution of noise in the Vc-Vc cross section in the upper left cross section of Figure 5. Similarly, the sound pressure map in the lower center of Figure 6 shows the sound pressure distribution of noise in the VIc-VIc cross section in the upper left cross section of Figure 6. Comparing these sound pressure maps, it can be seen that placing the Helmholtz resonator 140 in the position shown in Figure 6 reduces the sound pressure at the operator's right ear position RE compared to when it is placed in the position shown in Figure 5. On the other hand, even when the Helmholtz resonator 140 is placed in the position shown in Figure 6, the sound pressure at the operator's left ear position LE does not decrease compared to when it is placed in the position shown in Figure 5.

[0046] In this way, by appropriately adjusting the installation position of the Helmholtz resonator 140, the sound pressure of specific frequencies contained in the noise inside the cab 130 can be reduced at the ear positions LE and RE of the operator seated in the driver's seat 137 installed in the cab 130. Here, the frequency of noise whose sound pressure can be reduced is the same frequency as the resonance frequency f of the Helmholtz resonator 140. Note that the ear positions LE and RE of the operator are, for example, a three-dimensional region that includes the position of the operator's ear in the standard posture and the range in which the operator's ear may be located while operating the work machine 1.

[0047] Next, the processing performed by each part of the control device 120 will be explained with reference to Figures 7 and 8.

[0048] Figures 7 and 8 are flowcharts illustrating an example of processing performed by each part of the control device 120 in Figure 4. Below, we will first explain the position adjustment of the Helmholtz resonator 140 by manual operation by an operator without using the moving device 107, referring to Figure 7, and then explain the automatic position adjustment of the Helmholtz resonator 140 using the moving device 107, referring to Figure 8.

[0049] When the control device 120 starts the processing flow shown in Figure 7, it first executes process P1 to acquire the position LE and RE of the operator's ears. In this process P1, the acquisition unit 121 of the control device 120 shown in Figure 4 acquires the position LE and RE of the operator's ears while seated in the driver's seat 137 installed in the driver's cab 130. The acquisition unit 121 acquires the position LE and RE of the ears by recognizing the position of the operator's ears in a reference posture from an image of the operator taken by a camera inside the driver's cab 130 included in the sensor 108.

[0050] Furthermore, the acquisition unit 121 may acquire the operator's ear position LE,RE based on information such as the operator's height and weight input by the operator via, for example, a touch panel included in the operating device 109, and a comparison table of height, weight, and ear position LE,RE stored in memory beforehand. In this case, the acquisition unit 121 may acquire the position of the position-adjustable driver's seat 137 using a position sensor included in the sensor 108, and acquire the operator's ear position LE,RE based on the position of the driver's seat 137.

[0051] Next, the control device 120 performs a process P2 to determine the installation position of the Helmholtz resonator 140, as shown in Figure 7. In this process P2, the position determination unit 122 of the control device 120, shown in Figure 4, determines the installation position of the Helmholtz resonator 140 based on the ear-side positions LE and RE acquired by the acquisition unit 121.

[0052] More specifically, the control device 120's memory pre-stores, for example, an installation location map. The installation location map records as many different ear-side positions LE,RE as possible for operators, and the optimal installation position of the Helmholtz resonator 140 for those ear-side positions LE,RE. Here, the optimal installation position of the Helmholtz resonator 140 is the position of the Helmholtz resonator 140 that can most effectively reduce the sound pressure of noise at a frequency equal to the resonance frequency f at each ear-side position LE,RE, and this is determined in advance through analysis. The position determination unit 122 determines the installation position of the Helmholtz resonator 140 by referring, for example, the ear-side positions LE,RE acquired by the acquisition unit 121 and the installation location map pre-stored in memory.

[0053] Next, the control device 120 executes a process P3 to acquire the current position of the Helmholtz resonator 140, as shown in Figure 7. In this process P3, the guidance output unit 123 of the control device 120, as shown in Figure 4, acquires the current position of the Helmholtz resonator 140 using, for example, a position detection sensor included in the sensor 108. The position detection sensor can be, for example, a non-contact distance sensor or an encoder of a motor constituting the moving device 107.

[0054] Next, as shown in Figure 7, the control device 120 executes a process P4 to determine whether the current position of the Helmholtz resonator 140 is the same as the installation position. In this process P4, the guidance output unit 123 of the control device 120 shown in Figure 4 calculates, for example, the difference between the current position of the Helmholtz resonator 140 obtained in the previous process P3 and the installation position of the Helmholtz resonator 140 determined by the position determination unit 122 in the preceding process P2.

[0055] Furthermore, in this process P4, the guidance output unit 123 determines that the current position and the installation position are not equal (NO) if the difference between the current position and the installation position of the Helmholtz resonator 140 exceeds a predetermined threshold. In this case, the guidance output unit 123 executes process P5 to output guidance.

[0056] In this process P5, the guidance output unit 123 outputs information regarding the installation position of the Helmholtz resonator 140, determined by the position determination unit 122, to an output device 110, such as an image display device or an audio output device, installed in the driver's cab 130. Specifically, the guidance output unit 123 displays the amount of movement of the Helmholtz resonator 140 in the forward / backward, left / right, and up / down directions required to make the difference between the current position and the installation position zero on the image display device of the output device 110, or outputs it as audio from the audio output device of the output device 110.

[0057] The operator in the driver's cab 130 manually moves the Helmholtz resonator 140 according to the guidance on the amount of movement of the Helmholtz resonator 140 output by the output device 110. Subsequently, the control device 120 repeats the aforementioned processes P3 and P4.

[0058] As a result, in process P4, if the difference between the current position and the installation position of the Helmholtz resonator 140 falls below a predetermined threshold, the guidance output unit 123 determines that the current position and the installation position are equal (YES). In this case, the guidance output unit 123 executes process P6 to output that alignment is complete.

[0059] In this process P6, the guidance output unit 123 outputs to the image display device and audio output device of the output device 110 installed in the operator's cab 130 that the alignment of the Helmholtz resonator 140 to its optimal installation position is complete. After that, the control device 120 terminates the processing flow shown in Figure 7.

[0060] On the other hand, when performing automatic position adjustment of the Helmholtz resonator 140 using the moving device 107, the control device 120 starts the processing flow shown in Figure 8. Processes P1 and P2 shown in Figure 8 are the same as processes P1 and P2 shown in Figure 7. Meanwhile, in process P3 shown in Figure 8, the position control unit 124 of the control device 120 shown in Figure 4 acquires the current position of the Helmholtz resonator 140, for example, by the position detection sensor included in the sensor 108.

[0061] Next, in process P4 shown in Figure 8, the position control unit 124 calculates the difference between the current position of the Helmholtz resonator 140 obtained in the previous process P3 and the installation position of the Helmholtz resonator 140 determined by the position determination unit 122 in the preceding process P2. In this process P4, if the difference between the current position and the installation position of the Helmholtz resonator 140 exceeds a predetermined threshold, the position control unit 124 determines that the current position and the installation position are not equal (NO). In this case, the position control unit 124 executes process P7 to control the moving device 107.

[0062] In this process P7, the position control unit 124 controls the moving device 107 provided on the support mechanism 150 that supports the Helmholtz resonator 140 to move the Helmholtz resonator 140 from its current position to the installation position determined by the position determination unit 122. After that, the control device 120 repeats the aforementioned processes P3 and P4.

[0063] As a result, in process P4, if the difference between the current position and the installation position of the Helmholtz resonator 140 falls below a predetermined threshold, the position control unit 124 determines that the current position and the installation position are equal (YES). In this case, the position control unit 124 executes process P8 to output that the movement is complete.

[0064] In this process P8, the position control unit 124 outputs to the image display device and audio output device of the output device 110 installed in the driver's cab 130 that the movement of the Helmholtz resonator 140 to the optimal installation position is complete. After that, the control device 120 terminates the processing flow shown in Figure 8.

[0065] The operation of the work machine 1 of this embodiment will be described below.

[0066] As described above, the work machine 1 of this embodiment includes a driver's cab 130, a Helmholtz resonator 140 installed in the driver's cab 130, and a support mechanism 150 that supports the Helmholtz resonator 140 in a position-adjustable manner.

[0067] With this configuration, the position of the Helmholtz resonator 140, which is supported by the support mechanism 150 in a position-adjustable manner, can be adjusted to match the physique of the operator sitting in the cab 130. This makes it possible to move the Helmholtz resonator 140 to the optimal position where noise is reduced at the different ear positions LE and RE for each operator. Therefore, according to this embodiment, it is possible to provide a work machine 1 that can reduce noise at the ear positions LE and RE of the operator, regardless of the physique of the operator sitting in the cab 130.

[0068] Furthermore, as described above, the work machine 1 of this embodiment is further equipped with a control device 120. The control device 120 has an acquisition unit 121 and a position determination unit 122. The acquisition unit 121 acquires the ear positions LE and RE of the operator seated in the driver's seat 137 installed in the driver's cab 130. The position determination unit 122 determines the installation position of the Helmholtz resonator 140 based on the ear positions LE and RE acquired by the acquisition unit 121.

[0069] With this configuration, the acquisition unit 121 of the control device 120 can accurately acquire the ear positions LE and RE of the operator seated in the driver's seat 137. Furthermore, based on the ear positions LE and RE of the operator acquired by the acquisition unit 121, the position determination unit 122 of the control device 120 can determine the installation position of the Helmholtz resonator 140 that can reduce noise at the operator's ear positions LE and RE. Therefore, compared to the case where the operator in the driver's cab 130 determines the installation position of the Helmholtz resonator 140 by trial and error relying on their own hearing, the installation position that can reduce noise at the operator's ear positions LE and RE can be determined more quickly and accurately.

[0070] Furthermore, in the work machine 1 of this embodiment, the control device 120 has a guidance output unit 123 that outputs information regarding the installation position of the Helmholtz resonator 140, determined by the position determination unit 122, to an output device 110 installed in the operator's cab 130.

[0071] With this configuration, the operator in the driver's cab 130 can manually adjust the installation position of the Helmholtz resonator 140 based on information about the installation position of the Helmholtz resonator 140 output from the output device 110. This allows the operator to move the Helmholtz resonator 140 to its installation position more quickly and accurately compared to moving it by trial and error relying on their own hearing.

[0072] Furthermore, in the work machine 1 of this embodiment, the support mechanism 150 has a moving device 107 for moving the Helmholtz resonator 140. The control device 120 has a position control unit 124 that controls the moving device 107 to move the Helmholtz resonator 140 to the installation position determined by the position determination unit 122.

[0073] With this configuration, the Helmholtz resonator 140 can be automatically moved by the moving device 107 to the optimal installation position according to the different ear positions LE and RE of each operator, without relying on manual operation by the operator in the driver's cab 130. Therefore, compared to the case where the operator manually moves the Helmholtz resonator 140 by trial and error relying on their own hearing, the Helmholtz resonator 140 can be moved to the optimal installation position more easily, quickly, and accurately.

[0074] Furthermore, in the work machine 1 of this embodiment, the support mechanism 150 is provided on the ceiling 135 of the operator's cab 130.

[0075] With this configuration, the Helmholtz resonator 140 can be supported by a support mechanism 150 provided on the ceiling 135 of the driver's cab 130, allowing it to be placed in the upper part of the driver's cab 130 where there is relatively ample space. Therefore, even if the resonant frequency f is determined and the volume V of the container section 141 increases due to the limitations of the length L of the neck section 142 and the opening area s, the Helmholtz resonator 140 can be installed with ample space in the upper part of the driver's cab 130.

[0076] Furthermore, in the work machine 1 of this embodiment, the resonance frequency f of the Helmholtz resonator 140 is set according to the frequency of the noise inside the operator's cab 130.

[0077] This configuration allows the Helmholtz resonator 140 to resonate at the frequency of the noise inside the cab 130, thereby reducing the sound pressure of the noise inside the cab 130. Furthermore, the noise inside the cab 130 that is reduced by the Helmholtz resonator 140 has a sound pressure distribution corresponding to the position of the Helmholtz resonator 140. Therefore, by appropriately adjusting the position of the Helmholtz resonator 140 supported by the support mechanism 150, the noise at the ear-level positions LE and RE of the operator can be reduced regardless of the operator's physique.

[0078] As described above, according to this embodiment, it is possible to provide a work machine 1 that can reduce noise at the ear-level positions LE and RE of the operator, regardless of the operator's physique in the driver's cab 130.

[0079] Preferred embodiments of the present disclosure have been described above. However, the inventions of the present disclosure are not limited to the embodiments described above. Various modifications, substitutions, etc., can be applied to the embodiments described above without departing from the scope of the inventions of the present disclosure. Furthermore, each of the features described with reference to the embodiments described above may be combined as appropriate, as long as they do not contradict each other technically. [Explanation of Symbols]

[0080] 1. Working Machinery 107 Mobile device 110 Output device 130 Driver's cab 135 Ceiling 137 Driver's seat 140 Helmholtz resonators 150 Support mechanism 120 Control device 121 Acquisition Department 122 Positioning section 123 Guidance Output Section 124 Position Control Unit f resonance frequency LE ear position RE ear position

Claims

1. The driver's cab and, A Helmholtz resonator installed in the aforementioned driver's cab, The system includes a support mechanism for positionally supporting the Helmholtz resonator. Agricultural machinery.

2. An acquisition unit that acquires the position of the ear of the operator seated in the driver's seat installed in the driver's cab, The control device further includes a position determination unit that determines the installation position of the Helmholtz resonator based on the ear position acquired by the acquisition unit, The work machine according to claim 1.

3. The control device has a guidance output unit that causes the control device to output information regarding the installation position determined by the position determination unit to an output device installed in the driver's cab. The working machine according to claim 2.

4. The support mechanism has a moving device for moving the Helmholtz resonator, The control device includes a position control unit that controls the moving device to move the Helmholtz resonator to the installation position determined by the position determination unit. The working machine according to claim 2.

5. The support mechanism is provided on the ceiling of the driver's cab. The work machine according to claim 1.

6. The resonance frequency of the Helmholtz resonator is set according to the frequency of the noise inside the driver's cab. The work machine according to claim 1.

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