JPH1166485A - Traveling speed detector for construction vehicle having upper rotary body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately inform the speed of a lower traveling body to an upper rotary body at low cost by providing a speed detecting means for outputting the speed of the lower traveling body as an AC signal and a rotary transformer or the like for transmitting the AC signal. SOLUTION: For example, a hydraulic shovel 2 has a lower traveling body 4 and an upper rotary body 6 to turn with a turning shaft 3 as a center. Then, a speed detector 20 is provided for detecting the speed of the lower traveling body 4 and informing it to a driving room 7 at the upper body 6. The speed detector 20 has a speed detecting means 22 for outputting the speed of the lower traveling body 4 as the Ac signal. Besides, a rotary transformer 24 installed between the lower body 4 and the upper body 6 transmits the outputted AC signal to the upper body 6. The transmitted AC signal is inputted to a signal converting means 26 and operationally converted to the speed of the lower body 4. The operated speed is converted to a digital signal and outputted to a speed indicator and a speed controller or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling speed detecting device for a construction vehicle having an upper revolving body which is pivotably mounted on a lower traveling body. The present invention relates to a traveling speed detecting device that can appropriately transmit the vehicle speed and can be provided at a relatively low cost.

[0002]

2. Description of the Related Art For example, a hydraulic shovel is a typical construction vehicle having a lower traveling body and an upper revolving body mounted on the lower traveling body so as to be pivotable about a pivot axis extending substantially vertically. Can be This hydraulic excavator includes a driver's cab, a working device, an engine as a power source, and the like on an upper swing body. The power from the engine for traveling cannot be transmitted mechanically to the lower traveling body because of the existence of the revolving rotating part between the upper traveling body and the lower traveling body.
Therefore, as a traveling drive device provided in the lower traveling body,
2. Description of the Related Art A hydraulic motor that outputs mechanical shaft rotational force by supplying pressure oil is used. The rotation of the output shaft of the hydraulic motor causes the wheels or crawler tracks of the undercarriage to rotate,
The hydraulic excavator is driven. In order to transmit the traveling speed of the hydraulic excavator, that is, the rotation speed of the wheels or crawler belts of the lower traveling structure to the driver's cab of the upper revolving structure, as described above, the revolving rotating portion is provided between the lower traveling structure and the upper revolving structure. The following means are used because they cannot be transmitted mechanically because of their existence. (1) The amount of oil flowing through the hydraulic motor is measured by a flow meter, and the rotational speed of the hydraulic motor is estimated to determine the traveling speed. (2) A rotational speed detector is provided on the output rotary shaft of the hydraulic motor, and an output electric signal from the rotational speed detector is transmitted to the upper revolving unit via a slip ring provided on the revolving unit, a revolving joint using mercury, and the like. introduce.

[0003]

However, the conventional traveling speed detecting device of the above-described embodiment has the following problems to be solved. (1) In the method of measuring the amount of oil flowing through a hydraulic motor, internal leakage of a hydraulic motor, a hydraulic device in which hydraulic oil such as a hydraulic valve flows, a change in the amount of internal leakage due to a change in oil temperature, a change in hydraulic pressure, and a flow meter The rotational speed of the hydraulic motor estimated from the oil amount lacks accuracy and is likely to fluctuate due to imperfect accuracy of the vehicle, and the detected traveling speed is not sufficiently reliable. (2) In a system in which a rotation speed detector such as a rotary encoder is provided on an output rotary shaft of a hydraulic motor and an output electric signal is transmitted to an upper revolving unit via a slip ring provided in a revolving unit, Since the electrical signal is transmitted by the rotational contact of the slip ring, the electrical signal is susceptible to noise due to vibration and the like. Also, rotary joints utilizing mercury are expensive and impractical. (3) Therefore, it is difficult to accurately and appropriately transmit the traveling speed to the upper revolving superstructure, so that it is difficult to control the construction vehicle having the upper revolving superstructure such as automatic traveling and remote steering traveling.

[0004] The present invention has been made in view of the above-mentioned facts, and the technical problem thereof is that (1) the traveling speed of the lower traveling body is accurately transmitted to the upper revolving superstructure without being affected by noise. And (2) can be provided relatively inexpensively,
An object of the present invention is to provide a traveling speed detection device for a construction vehicle having an upper revolving superstructure.

[0005]

According to the present invention, in order to solve the above-mentioned technical problems, the traveling speed of the lower traveling body is output by an AC electric signal, and an alternating current is supplied between the upper rotating body and the lower traveling body. A rotary transformer for transmitting an electric signal is provided, and the transmitted AC electric signal is converted into a traveling speed in the upper swing body.

That is, according to the present invention, as a traveling speed detecting device for a construction vehicle having an upper revolving structure that solves the above technical problem, the traveling speed detecting device is provided on the lower traveling structure and the lower traveling structure is provided. A traveling speed detecting means for outputting the traveling speed of the vehicle by an AC signal, a rotary transformer provided between the lower traveling body and the upper revolving body around the pivot axis for transmitting the AC signal, and Signal converting means provided on a body for converting the AC signal from the rotary transformer into a traveling speed. A traveling speed detecting device for a construction vehicle having an upper revolving superstructure is provided.

In a preferred embodiment, the rotary transformer includes a stator mounted on the lower traveling body and a rotor mounted on the upper rotating body and rotatably disposed around the stator. An AC signal is induced in the rotor by exciting the stator with the AC signal from the traveling speed detecting means. The rotary transformer is conveniently attached to a swing hydraulic joint provided between the lower traveling structure and the upper swing structure with the swing axis as the center of rotation.

In the traveling speed detecting apparatus for a construction vehicle having an upper revolving unit according to the present invention, the traveling speed of the lower traveling unit is output by an AC signal, and is contactless through a rotary transformer provided in the revolving unit. And transmitted to the upper revolving superstructure, and converted into the traveling speed. Therefore, the traveling speed signal is transmitted to the upper revolving superstructure accurately and without being affected by noise. In addition, a traveling speed detecting means that is less expensive than an expensive rotary joint using mercury is provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a construction vehicle traveling speed detecting device having an upper revolving structure constructed according to the present invention will be described below in more detail with reference to the accompanying drawings.

Referring to FIG. 1, a hydraulic shovel, generally designated by the reference numeral 2, which is a typical construction vehicle having an upper revolving structure, has a lower traveling structure 4 and a substantially vertical structure on the lower traveling structure 4. And an upper revolving unit 6 that is mounted so as to be pivotable about a pivot axis 3 that extends. The upper swing body 6 is provided with a driver's cab 7, a working device 8, an engine room 9 in which an engine (not shown) as a power source is housed, and the like. The lower traveling body 4 includes a pair of right and left crawler traveling devices 5, 5.
(One of which is visible in FIG. 1), the traveling device 5 includes a sprocket 5a as a driving wheel, an idler 5b as an idler wheel, and a sprocket 5a and an idler 5b.
And a crawler belt 5c wound therearound. A turning hydraulic joint 10 provided at a turning center portion discharges hydraulic oil from a hydraulic pump (not shown) driven by an engine.
To the hydraulic motor 12 connected to the sprocket 5a, the sprocket 5a is rotated, the crawler belt 5c is rotationally driven, and the hydraulic shovel 2 is caused to travel.

Continuing the description with reference to FIG. 1, the hydraulic excavator 2 includes a traveling speed detecting device 20 for detecting the traveling speed of the lower traveling unit 4 and transmitting the traveling speed to the cab 7 of the upper revolving unit 6. . The traveling speed detecting device 20 is provided on the lower traveling unit 4 and outputs traveling speed of the lower traveling unit 4 by an AC signal. For transmitting an output AC signal to the upper-part turning body 6
And signal conversion means 26 provided on the upper swing body 6 for converting an AC signal from the rotary transformer 24 into a traveling speed.

The traveling speed detecting means 22 will be described with reference to FIG. 2. The traveling speed detecting means 22 is attached to the output shaft 12a of the hydraulic motor 12, and outputs the rotation speed of the output shaft 12a as an AC signal. Speed detector 22a. For example, a resolver can be used as the speed detector 22a. The resolver detects and outputs the rotation speed of the output shaft 12a at the rotation frequency per unit time. The rotational driving force of the output shaft 12a of the hydraulic motor 12 is transmitted to the sprocket 5a via the gear reducer 12b,
c. Therefore, the traveling speed of the lower traveling unit 4 is obtained from the reduction ratio of the gear reducer 12b, the turning radius of the sprocket 5a, and the rotating speed of the output shaft 12a.

Referring to FIG. 3, the rotary transformer 24 will be described. The rotary transformer 24 is a kind of transformer, and an iron core and a coil are provided between the lower traveling body 4 and the upper revolving body 6 around the revolving axis 3 as a center of rotation. It is divided so as to be rotatable. The rotary transformer 24 is attached to the turning hydraulic joint 10 provided at the turning center.

Before explaining the rotary transformer 24, the swing hydraulic joint 10 to which the rotary transformer 24 is attached will be described. The swing hydraulic joint 10 is a swing axis 3 between the lower traveling body 4 and the upper swing body 6 of the excavator 2. Is a well-known swivel joint that is provided at the center of swivel through which connects the hydraulic pipeline between the lower traveling structure 4 and the upper revolving structure 6. Briefly describing the structure, a swing hydraulic joint 10 includes a shaft 10a erected on the lower traveling body 4 and a housing 10b rotatably attached to the shaft 10a and attached to the upper swing body 6. And Thus, the housing 10b is formed rotatable about the pivot axis 3 with respect to the shaft 10a. A plurality of connection ports to which a plurality of hydraulic pipes of the upper swing body 6 are connected are provided on the outer peripheral surface of the housing 10b.
In a, a plurality of flow paths corresponding to the connection ports and a plurality of connection ports to which a plurality of hydraulic pipes of the lower traveling body 4 are connected at an end on the lower traveling body 4 side are provided. The individual flow paths are sealed and separated. As an example of the hydraulic piping, a hydraulic piping 11a on the upper swing body 6 side and a corresponding hydraulic piping 11b on the lower traveling body 4 are illustrated.

A rotary transformer 24 is attached to an end of the swing hydraulic joint 10 opposite to an end to be attached to the upper swing body 6 and the lower traveling body 4. The rotary transformer 24 includes a stator 24a having an iron core and a coil, and a stator 24a.
And a rotor 24b having a core and a coil rotatably arranged around the rotor. The stator 24a has an inner case 24c formed in an annular shape.
Reference numeral 4c is fixed to a hollow shaft 10c which is fixedly provided upright at the end of the shaft 10a of the turning hydraulic joint 10 in the axial direction of the shaft 10a. The rotor 24b has an outer case 24d formed in an annular shape, and the outer case 24d is fixed to an end of the housing 10b of the turning hydraulic joint 10. A bearing 24e is interposed between the inner case 24c and the outer case 24d.

The rotary transformer 24 is of a well-known type based on the principle of a transformer, and is formed by dividing a core of a transformer into a stator and a rotor so that the input side and the output side can be relatively rotated. By exciting the coil of the stator 24a with an AC voltage, an AC output voltage is induced in the coil of the rotor 24b. That is, by exciting the stator 24 a with the AC signal from the traveling speed detecting means 22, an AC signal is induced and transmitted to the rotor 24.

Returning to FIG. 1, the signal converting means 26 provided in the cab 7 is provided with an AC electric signal detected by the traveling speed detecting means 22 and inputted through the rotary transformer 24. , The travel speed of the lower traveling body 4 is calculated and converted into a digital signal, which is output to a speedometer / speed controller 28 (see FIG. 4). The signal conversion means 26 is connected to the output shaft 12a of the hydraulic motor 12 from the sprocket 5
Values such as the reduction ratio up to a and the radius of rotation of the sprocket 5a are input and stored in advance. When an AC signal is input from the rotary transformer 24, the rotational speed of the output shaft 12a is obtained from the rotational frequency of the output shaft 12a per unit time, which is the input signal, and the rotational speed of the output shaft 12a is calculated from the stored reduction ratio and rotational radius. The traveling speed of the lower traveling body 4 is calculated.

The operation of the traveling speed detecting device 20 of the construction vehicle 2 having the upper revolving structure as described above will be described with reference to FIGS. The traveling speed of the lower traveling body 4 is detected by the rotation speed of the output shaft of the hydraulic motor 12,
An AC signal is output, and the stator 24 of the rotary transformer 24 is output.
is input to a. FIG. 4 shows a pair of left and right hydraulic motors 12, 12. (2) When the stator 24a is excited by the AC signal transmitted and input to the rotary transformer 24, an AC output voltage is induced and output to the coil of the rotor 24b in accordance with the input AC signal. (3) The output AC signal is input to the signal conversion means 26 and is arithmetically converted into the traveling speed of the lower traveling body 4. (4) The calculated traveling speed is converted into a digital signal and output to a speedometer / speed control device 28 or the like. (5) In the above-described flow of the AC signal for transmitting the traveling speed, the rotary transformer 24 for transmitting the signal does not have a signal transmission unit by contact such as a slip ring. Therefore, the signal is transmitted without being affected by noise.
Further, since the traveling speed is transmitted by the frequency of the AC signal, an accurate traveling speed is transmitted. (6) The signal transmission by the rotary transformer 24 is not affected by the temperature and is not affected by the length of the signal wiring.
It is suitable for use in various types of construction machines, such as miniature, jumbo, etc., which are operated at various sites such as extreme cold and burning. (7) By attaching the rotary transformer 24 to the turning hydraulic joint 10, the rotary transformer 24 can be disposed compactly. (8) Conventionally, it is difficult to obtain an accurate speed, so that it is possible to easily perform automatic traveling control, remote-controlled traveling control, and the like of a construction vehicle having an upper revolving structure, which has been difficult. (9) Since the rotation speed of each of the hydraulic motors of the pair of left and right traveling devices can be accurately monitored, the construction vehicle goes straight by synchronizing the rotation speeds of the left and right hydraulic motors, which has conventionally been difficult to control. It is possible to easily perform a predetermined left-right turning operation by providing a predetermined difference between the running speeds or the rotational speeds of the left and right hydraulic motors. (10) By employing a rotary transformer for signal transmission, a rotational speed detecting device can be provided at a lower cost than transmission by a rotary joint using expensive mercury.

As described above, the present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above-described embodiments, and can be variously modified or modified within the scope of the present invention. It is. For example, (1) In the present embodiment, the traveling speed of the undercarriage is detected at the output shaft of the hydraulic motor. However, at other appropriate locations, for example, at a rotating portion such as a gear reducer or a sprocket, When a wheel-type undercarriage is provided, it can be detected on an axle or a propulsion shaft that drives wheels. (2) In the present embodiment, the engine that is the power source of the construction vehicle is provided on the upper revolving unit, but the engine has an upper revolving unit such as a crane vehicle provided on the lower traveling unit. Similarly, in a construction vehicle, a rotation transformer is provided at the center of rotation between the lower traveling structure and the upper revolving structure, and the traveling speed of the lower traveling structure can be transmitted to the upper revolving structure. (3) If it is necessary to transmit power or the like from the upper revolving unit to the lower traveling unit, a rotary transformer for power supply can be provided and transmitted to the lower traveling unit, similarly to the rotary transformer for signal transmission described above.

[0020]

According to the traveling speed detecting device for a construction vehicle having an upper revolving structure constructed according to the present invention, (1) the traveling speed of the lower traveling structure can be accurately turned without being affected by noise. There is provided a traveling speed detection device for a construction vehicle having an upper revolving structure that can be transmitted to a body and (2) can be provided relatively inexpensively.

[Brief description of the drawings]

FIG. 1 is a side view of a hydraulic excavator provided with a traveling speed detection device for a construction vehicle having an upper revolving structure configured according to the present invention.

FIG. 2 is a cross-sectional view of a lower traveling body drive unit provided with traveling speed detection means as viewed in the direction of arrows AA in FIG.

FIG. 3 is a cross-sectional view of the swing hydraulic coupling and the rotary transformer, as viewed in the direction of arrows BB in FIG. 1;

FIG. 4 is a block diagram showing a signal flow of a traveling speed detection device configured according to the present invention.

[Description of Signs] 2: Hydraulic excavator (construction vehicle having upper revolving unit) 3: Revolving axis 4: Lower traveling unit 6: Upper revolving unit 10: Revolving hydraulic joint 22: Traveling speed detecting means 22a: Speed detector 24: Rotary transformer 24a: Stator 24b: Rotor 26: Signal conversion means

Claims (3)

[Claims] 1. The traveling speed of a lower traveling body of a construction vehicle having a lower traveling body and an upper revolving body mounted on the lower traveling body so as to be pivotable about a pivot axis extending substantially vertically. A traveling speed detecting device for detecting the traveling speed of the lower traveling structure and outputting the traveling speed of the lower traveling structure by an AC signal. A rotary transformer provided between the lower traveling structure and the upper revolving structure with the revolving axis as a center of rotation for transmitting the AC signal, and traveling the alternating current signal from the rotating transformer provided on the upper revolving structure. A traveling speed detecting device for a construction vehicle having an upper revolving superstructure, comprising: signal converting means for converting the speed into a speed. 2. A rotary transformer comprising: a stator attached to the lower traveling body; and a rotor attached to the upper revolving body and rotatably disposed around the stator. The traveling speed detecting device for a construction vehicle having an upper revolving superstructure according to claim 1, wherein an AC signal is induced in the rotor by exciting the rotor with the AC signal from the traveling speed detecting means. 3. The upper swing according to claim 2, wherein the rotary transformer is attached to a swing hydraulic joint provided between the lower traveling structure and the upper swing structure with the swing axis as a center of rotation. A traveling speed detection device for a construction vehicle having a body.