JP2012126296A - Sound insulation structure of cab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound insulation structure of a steering shaft hole into which a steering shaft is inserted, which is provided to the bottom part of a tiltable cab.SOLUTION: In a bottom part of the cab 2, a steering shaft hole 17 into which the steering shaft 9 is inserted from the inside of the cabin of the cab 2 is provided. A transfer gear device 11 is fixed to a frame 3, and includes a joint part 10 to which the lower steering shaft 9 is connected. A hole cover 19 includes a cover body and an annular rib. The cover body has an insertion hole into which the joint part 10 is inserted, and is supported on the upper part of the transfer gear device 11 in a state that the joint 10 is inserted. A rib is fixed around the insertion hole to project upward from the cover body 19. When the cab 2 is in a non-tilt position, the rib is closely adhered to the lower surface of the steering shaft hole 17.

Description

  The present invention relates to a tiltable cab sound insulation structure.

  Japanese Utility Model Laid-Open No. 61-203171 describes a steering shaft structure of a tilt cab vehicle. The steering shaft is connected to an input shaft of a steering gear device fixed to the chassis frame via a universal joint. An opening through which the universal joint is inserted is provided at the bottom of the cabin. The steering shaft and the universal joint are covered with a cylindrical column tube.

  Japanese Patent Laying-Open No. 2005-280564 describes a vehicle steering device. In this device, a lower joint cover on the engine room side is fixed with a bolt to an opening of a dashboard that partitions the vehicle compartment and the engine room. The pinion shaft connected to the steering shaft extends through the opening of the lower joint cover and extends into the steering gear box disposed outside the vehicle compartment. A rubber grommet is attached to the upper end of the steering gear box, and the annular lip of the grommet abuts on the lower joint cover so as to surround the opening of the lower joint cover. The grommet prevents engine room noise from entering the vehicle compartment through the opening of the lower joint cover.

Japanese Utility Model Publication No. 61-203171 JP 2005-280564 A

  In the tilt cab vehicle disclosed in Japanese Utility Model Publication No. 61-203171, the steering shaft moves as the cabin tilts forward (cab tilt). Must be set long). For this reason, noises such as engine radiated sound and road noise are likely to enter the passenger compartment through the opening.

  Note that the column tube simply covers the steering shaft and the universal joint, does not seal the inside of the column tube with respect to the outside (vehicle compartment), and does not provide a desired sound insulation effect.

  In addition, the sound insulation structure described in Japanese Patent Application Laid-Open No. 2005-280564 is a structure in which the lower joint cover on the engine room side is fixed to the dashboard on the passenger compartment side with a bolt, so that the tilt cab type in which the passenger compartment side rotates and moves is used. It cannot be applied to vehicles.

  Accordingly, an object of the present invention is to provide a sound insulation structure for a cab that exhibits excellent sound insulation performance against noise entering the vehicle interior from an opening through which a steering shaft is inserted in a tiltable cab.

  In order to achieve the above object, the present invention provides a sound insulation of a cab that can be set to a non-tilt position where the front end side and the other end side are supported by the vehicle body frame and a tilt position where the other end side is rotated upward about the front end side. The structure includes an opening, a steering shaft, a gear device, and a sound insulation member. The opening is provided at the bottom of the cab. The steering shaft extends from the cabin of the cab through the opening through the cab, and tilts as the cab rotates. The gear device has a shaft coupling portion to which the lower end portion of the steering shaft is coupled, and is fixed to the vehicle body frame with the shaft coupling portion exposed upward. The sound insulating member is formed with an insertion hole through which the shaft coupling portion is inserted, and a plate-like portion supported by the upper portion of the gear device in a state where the shaft coupling portion is inserted into the insertion hole, and above the plate-like portion around the insertion hole. And an elastic annular rib closely contacting the lower surface of the bottom of the cab around the opening in a state where the cab is set at a non-tilt position.

  In the above configuration, the opening at the bottom of the cab through which the steering shaft is inserted has a predetermined length in the front-rear direction of the vehicle so as to allow the steering shaft to move with the rotational movement of the cab. A relatively large gap is set between them.

  In the state where the cab is set at the non-tilt position, the plate-like portion of the sound insulating member covers the opening from below, and the elastic annular rib protruding upward from the plate-like portion is in close contact with the lower surface of the bottom of the cab around the opening, The shaft coupling portion of the gear device is inserted through the insertion hole of the plate-like member. For this reason, the opening and the space below the cab communicate with each other only through the gap between the shaft coupling portion and the insertion hole. However, since the sound insulating member is supported on the upper part of the gear device fixed to the vehicle body frame, and the shaft coupling portion does not move with the rotational movement of the cab, it is not necessary to set the insertion hole as large as the opening. . Therefore, the gap between the shaft connecting portion and the insertion hole can be set small, and the lower part of the opening can be almost sealed by the sound insulating member. As a result, noise such as engine radiated sound and road noise entering the cabin of the cab from the opening at the bottom of the cab can be well insulated by the sound insulating member.

  The elastic annular rib may enter the opening as the cab rotates to the non-tilt position, and may be in close contact with the inner peripheral surface of the opening with the cab set to the non-tilt position.

  In the above configuration, when the cab is set at the non-tilt position, the elastic annular rib closely contacts the lower surface of the bottom of the cab around the opening and also enters the opening and closely contacts the inner peripheral surface of the opening. Even when the relative position between the cab and the sound insulation member varies due to vibration during traveling, the close contact state between the cab and the elastic annular rib is continuously maintained. Therefore, noises such as engine radiated sound and road noise that enter the cabin of the cab from the opening can be reliably shielded.

  The sound insulation member is disposed around the shaft coupling portion between the plate-like portion and the upper portion of the gear device, and between the plate-like portion and the upper portion of the gear device with the cab set to the non-tilt position. You may have the elastic seal part to seal.

  In the above configuration, in the state where the cab is set to the non-tilt position, the elastic seal portion seals between the plate-shaped portion and the upper portion of the gear device, so that the sealing performance below the opening by the sound insulating member is improved. Therefore, noises such as engine radiated sound and road noise that enter the cabin of the cab from the opening can be reliably shielded.

  ADVANTAGE OF THE INVENTION According to this invention, in the cab which can be tilted, the sound insulation performance outstanding with respect to the noise which infiltrates into the vehicle interior of a cab from the opening of the cab which a steering shaft penetrates can be exhibited.

It is a side view which shows the sound insulation structure of this embodiment. It is a side view which shows the tilting operation | movement of the cab of the vehicle of FIG. It is an expanded view of a hole cover. It is explanatory drawing of the hole cover at the time of a tilt. It is explanatory drawing of the hole cover at the time of non-tilt.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the figure, FR indicates the front of the vehicle and UP indicates the upper side. In the following description, the front-rear direction means the front-rear direction of the traveling direction of the vehicle, and the left-right direction means the left-right direction in a state of facing the front of the traveling direction of the vehicle.

  As shown in FIG. 1, a cab overtrack (vehicle) 1 according to this embodiment includes a cab 2, a chassis frame (body frame) 3, a steering wheel 6, an upper steering shaft 7, and a lower steering shaft 9. And a transfer gear device (gear device) 11 and the like.

  The chassis frame 3 extends in the vehicle front-rear direction on both sides of the vehicle 1 in the vehicle width direction, and the front end portions of the left and right chassis frames 3 are connected by cross members. The front end portion of the cab 2 is supported so as to be rotatable about a tilt shaft 4 fixed to the front end portion of the chassis frame 3. A cab mount 5 that supports the rear end portion of the cab 2 from below is fixed to the chassis frame 3. The cab 2 at the non-tilt position has a front end portion supported by the tilt shaft 4 and a rear end portion supported by the cab mount 5. The cab 2 at the non-tilt position is set at the tilt position by rotating the rear end side upward about the tilt axis 4 (see FIG. 2).

  A steering wheel 6 that is rotated by the driver when the vehicle 1 is steered is disposed in the front part of the cabin of the cab 2. An upper steering shaft 7 that transmits the rotation of the steering wheel 6 extends downward from the steering wheel 6, and a lower end of the upper steering shaft 7 is connected to the lower steering shaft 9 via a universal joint 8. The transfer gear device 11 is fixed to the chassis frame 3 and has a joint portion (shaft coupling portion) 10 that is exposed from the transfer gear device 11 and extends upward. A lower end portion of the lower steering shaft 9 is connected to the joint portion 10. The rotation of the steering wheel 6 is transmitted to the transfer gear device 11 via the upper steering shaft 7 and the lower steering shaft 9, and the chassis frame 3 is located behind the transfer gear device 11 by the joint shaft 12 extending rearward from the transfer gear device 11. Is transmitted to a power steering unit 13 that is fixed to the power steering unit 13.

  A steering shaft hole (opening) 17 is provided at the bottom 16 of the cab 2. In a state where the cab 2 is set to the non-tilt position, the joint portion 10 of the transfer gear device 11 connected to the lower steering shaft 9 is inserted through the steering shaft hole 17 and protrudes into the vehicle interior of the cab 2. When the cab 2 shifts to the tilt position, the lower steering shaft 9 tilts forward about the joint portion 10 of the transfer gear device 11 as the cab 2 moves forward and upward on the rear end side. As the cab 2 rotates, the steering shaft hole 17 at the bottom 16 of the cab 2 also moves forward and upward. However, since the joint 10 of the transfer gear device 11 does not move, the cab 2 is set in the tilt position. The lower steering shaft 9 passes through the steering shaft hole 17. In the tilt position, the position where the lower steering shaft 9 passes through the steering shaft hole 17 is behind the position where the joint portion 10 passes through the steering shaft hole 17 in the non-tilt position. Even if the insertion position of the joint portion 10 or the lower steering shaft 9 is moved with the tilt operation of the cab 2, the steering shaft hole 17 is moved in the front-rear direction so that the joint portion 10 or the lower steering shaft 9 does not interfere with the cab 2. A relatively large gap is set between the joint portion 10 or the lower steering shaft 9 and the steering shaft hole 17 having a predetermined length.

  The periphery of the upper steering shaft 7 is covered with a steering column cover 14. The periphery of the universal joint 8 and the lower steering shaft 9 is covered with a cylindrical steering shaft cover 15. The upper end of the steering shaft cover 15 is located at the lower end of the steering column cover 14, and the lower end of the steering shaft cover 15 is fixed to the outer periphery of the steering shaft hole 17 in the cabin of the cab 2. An inspection window 18 with a door that can be opened and closed is provided on the lower rear side of the steering shaft cover 15 to inspect the joint portion 10.

  A hole cover (sound insulation member) 19 is supported on the upper portion of the transfer gear device 11. As shown in FIG. 3, the hole cover 19 includes a rubber mount (elastic seal portion) 20, a cover main body (plate-like portion) 21, and a rib (elastic annular rib) 22. The rubber mount 20 is formed of an annular vibration-proof rubber material having an insertion hole 20a through which the joint portion 10 of the transfer gear device 11 is inserted. The rubber mount 20 is disposed on the transfer gear device 11 in a state where the joint portion 10 is inserted through the insertion hole 20a (see FIG. 4). The cover main body 21 is a plate-like member having a size covering the steering shaft hole 17, and an insertion hole 21 b through which the joint portion 10 of the transfer gear device 11 is inserted is formed at the center of the cover main body 21. The cover body 21 is disposed on the upper surface of the rubber mount 20 in a state where the joint portion 10 is inserted. When the cab 2 moves from the non-tilt position to the tilt position, the joint portion 10 at the upper part of the transfer gear device 11 does not move, so that the gap between the joint portion 10 and the insertion hole 21b is set as large as the steering shaft hole 17. do not have to. Accordingly, the gap between the insertion hole 21b of the cover main body 21 and the joint portion 10 is set to be small as long as the rotation of the joint portion 10 is not hindered.

  A rib 22 is fixed to the upper surface of the cover body 21 around the insertion hole 21b. The rib 22 is formed of an annular vibration-proof rubber material and protrudes upward from the cover body 21. The spring constant of the rib 22 is set smaller than the spring constant of the rubber mount 20. When the cab 2 is in the non-tilt position, the outer peripheral edge of the upper surface 22a of the rib 22 is located inside the inner peripheral edge of the steering shaft hole 17, and the outer peripheral edge of the lower surface 22b of the rib 22 is the inner peripheral edge of the steering shaft hole 17. It is located outside. When the cab 2 is in the non-tilt position, the distance (height) from the upper surface 21a of the cover main body 21 to the upper surface 22a of the rib 22 is the steering of the upper surface 21a of the cover main body 21 to the upper surface of the bottom 16 of the cab 2. The distance is set longer than the distance to the peripheral edge portion of the shaft hole 17 (hereinafter referred to as the upper surface of the steering shaft hole 17) 17a. Further, the outer peripheral edge of the lower surface 22b of the rib 22 is located inside the outer peripheral edge of the cover main body 21, and the outer peripheral surface 22c of the rib 22 is increased in taper from the upper surface 22a of the rib 22 toward the lower surface 22b of the rib 22. (See FIGS. 4 and 5).

  In the present embodiment, a relatively large gap is set between the joint shaft 10 or the lower steering shaft 9 that passes through the steering shaft hole 17 and the steering shaft hole 17.

  When the cab 2 starts to move from the tilt position to the non-tilt position, the steering shaft hole 17 provided in the bottom portion 16 of the cab 2 is lowered, and the joint portion 10 of the transfer gear device 11 is steered from below the bottom portion 16 of the cab 2. The shaft hole 17 is inserted. In a state where the cab 2 is set to the non-tilt position, the cover main body 21 of the hole cover 19 covers the steering shaft hole 17 from below in a state where the joint portion 10 is inserted into the insertion hole 21 b of the cover main body 21. The outer peripheral edge of the upper surface 22a of the rib 22 is located inside the inner peripheral edge of the steering shaft hole 17, and the height from the upper surface 21a of the cover body 21 to the upper surface 22a of the rib 22 is as high as the upper surface 17a of the steering shaft hole 17. Therefore, the upper portion of the rib 22 enters the steering shaft hole 17 that descends from below. The outer peripheral edge of the lower surface 22b of the rib 22 is located outside the inner peripheral edge of the steering shaft hole 17, and the outer peripheral surface 22c of the rib 22 is enlarged in a taper shape from the upper surface 22a toward the lower surface 22b. The outer peripheral surface 22 c of the rib 22 is in close contact with the lower surface 17 b of the steering shaft hole 17. Furthermore, the outer peripheral surface 22c of the rib 22 is pressed and deformed by the lower surface 17b of the descending steering shaft hole 17, and is in close contact with almost the entire inner peripheral surface 17c of the steering shaft hole 17 (see FIG. 5).

  Further, the rubber mount 20 is pressed and deformed by the descending steering shaft hole 17 to seal between the cover main body 21 and the upper part of the transfer gear device 11. Since the spring constant of the rib 22 is set smaller than that of the rubber mount 20, the rubber mount 20 does not hinder the deformation of the rib 22. Accordingly, the gap between the insertion hole 21 b of the cover body 21 and the joint portion 10 is closed, and the steering shaft hole 17 is reliably sealed from below by the cover hole 19.

  Thus, according to the present embodiment, the steering shaft hole 17 is reliably sealed from below by the cover hole 19 in a state where the cab 2 is set to the non-tilt position. Noises such as engine radiated sound and road noise that enter the cabin of the cab 2 from the outside of the cab 2 can be reliably shielded.

  The ribs 22 are in close contact with the lower surface 17b of the steering shaft hole 17, and enter the steering shaft hole 17 to be in close contact with the inner peripheral surface 17c. As a result, even if the relative position between the hole cover 19 and the steering shaft hole 17 varies due to vibrations during traveling of the vehicle 1, the rib 22 of the hole cover 19 and the inner peripheral surface 17 c of the steering shaft hole 17. The contact state with is continuously maintained. Therefore, noise such as engine radiation sound and road noise entering the cabin of the cab 2 from the steering shaft hole 17 can be reliably insulated.

  In addition, rubber mounts 20 and ribs 22 formed of anti-vibration rubber material are disposed at the lower and upper portions of the cover body 21, respectively, so that the vehicle 1 travels to the cab 2 via the transfer gear device 11. It is possible to reduce vibrations and the like caused by.

  Further, since the hole cover 19 is supported on the upper portion of the transfer gear device 11 fixed to the chassis frame 3, it does not hinder the tilt operation of the cab 2.

  Further, since the joint portion 10 of the transfer gear device 11 is inserted through the hole cover 19 from below while the cab 2 is set to the non-tilt position, the steering shaft is disposed in the state in which the hole cover 19 is disposed as in the related art. The joint portion 10 can be inspected from the inspection window 18 provided in the cover 15.

  Note that the height from the upper surface 21a of the cover body 21 to the upper surface 22a of the rib 22 may be set higher than the height from the lower surface 17b of the steering shaft hole 17 when the cab 2 is in the non-tilt position. The height from the upper surface 21a of the 21 to the upper surface 17a of the steering shaft hole 17 may be lower. The rib 22 may be in close contact with the lower surface 17 b of the steering shaft hole 17. For example, the inner periphery of the upper surface 22 a of the rib 22 may be set larger than the outer periphery of the steering shaft hole 17. Even in such a case, the rib 22 is in close contact with the lower surface 17b of the steering shaft hole 17, so that the steering shaft hole 17 is reliably sealed from below by the hole cover 19, and the cab 2 of the cab 2 is removed from the steering shaft hole 17. Noise such as engine radiated sound and road noise entering the passenger compartment can be well insulated.

  Further, the rubber cover 20 may be omitted from the hole cover 19. Even in this case, since the rib 22 is in close contact with the lower surface 17b of the steering shaft hole 17, the steering shaft hole 17 is set by setting a small gap between the insertion hole 21b of the cover body 21 and the joint portion 10 to be inserted. Can be substantially sealed by the cover main body 21 and the rib 22. Therefore, it is possible to satisfactorily isolate noise such as engine radiated sound and road noise that enters the cabin of the cab 2 from the steering shaft hole 17.

  As mentioned above, although the embodiment to which the invention made by the present inventor is applied has been described, the present invention is not limited by the discussion and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it is needless to say that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

  The present invention is widely applicable to tilt type cab over vehicles.

1: Cab over truck 2: Cab 3: Chassis frame (body frame)
6: Steering wheel 9: Lower steering shaft (steering shaft)
10: Joint part (shaft connecting part)
11: Transfer gear device (gear device)
16: Bottom of cab 17: Steering shaft hole (opening)
17c: Steering shaft hole inner peripheral surface (opening inner peripheral surface)
19: Hall cover (sound insulation member)
20: Rubber mount (elastic seal)
21: Cover body (plate-shaped part)
21b: Insertion hole (insertion hole of plate-like part)
22: Rib (elastic annular rib)
22c: rib outer peripheral surface

Claims (3)

A sound insulation structure of the cab that can be set to a non-tilt position where the front end side and the other end side are supported by the vehicle body frame and a tilt position where the other end side is rotated upward about the front end side,
An opening provided in the bottom of the cab;
A steering shaft that passes through the opening from the cabin of the cab and extends below the cab, and tilts with the rotational movement of the cab;
A gear device having a shaft connecting portion to which a lower end portion of the steering shaft is connected, and being fixed to the vehicle body frame with the shaft connecting portion exposed upward;
An insertion hole through which the shaft coupling portion is inserted is formed, and a plate-like portion supported by the upper portion of the gear device in a state where the shaft coupling portion is inserted into the insertion hole, and the plate-like portion around the insertion hole And a sound insulation member having an elastic annular rib that protrudes upward from the upper surface and is in close contact with the lower surface of the bottom of the cab around the opening in a state where the cab is set at a non-tilt position. Sound insulation structure. The cab sound insulation structure according to claim 1,
The elastic annular rib enters the opening as the cab rotates to a non-tilt position, and closely contacts an inner peripheral surface of the opening in a state where the cab is set to a non-tilt position. The sound insulation structure of the cab. The sound insulation structure for a cab according to claim 1 or 2,
The sound insulation member is disposed around the shaft coupling portion between the plate-like portion and the upper portion of the gear device, and the plate-like portion and the gear device are arranged in a state where the cab is set at a non-tilt position. A sound insulation structure for a cab, characterized by having an elastic seal portion that seals between the upper portion.

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