JP2006220306A - Electric hydraulic motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric hydraulic motor capable of avoiding that a return oil passage becomes very high pressure. <P>SOLUTION: The electric hydraulic motor is connected to a hydraulic actuator for revolving an output shaft 21 by the working oil pressure, the pulse motor 31 for revolving a drive shaft 32 according to the electric input signal, the hydraulic actuator, a main oil passage 11a for leading the operation oil supplied from the outside and a return oil passage 11b for leading the working oil from the hydraulic actuator to the outside. It connects with the hydraulic actuator, the spool valve 43 to change the connection with a main oil passage 11a and the return oil passage 11b, the first helical gear 41 to be connected with the spool valve 43 and the output shaft 21 by responding to the revolution of the drive shaft 32. The first helical gear 41 for engaging so as to cross with the helical gear 41 and the separation wall 11g that is established so as to surround the second helical gear 42 are prepared, and the second helical gear 42 side of the separation wall 11g is made to be a drain oil passage and the opposite side of the second helical gear 42 of the separation wall 11g is made to be the return oil passage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrohydraulic motor used in a hydraulic excavator, an asphalt finisher, a machine tool, a crane, and the like, and more specifically, an electrohydraulic that can release excess hydraulic oil generated when driving is stopped without using excessive energy. It relates to the motor.

  As shown in FIGS. 4 and 5, the conventional electrohydraulic motor has a cup-shaped first housing 50 and a second housing 52 fastened and fixed to the first housing 50 with bolts 52. Yes. The first casing 50 is formed with a main oil passage 50a, a return oil passage 50b, and two communication oil passages (50c, 50d).

  The output shaft is rotatably supported by the first casing 50 and the second casing 52 by bearings (54, 55). The first helical gear 56 is rotatably connected to the spool valve 59 via bearings (54, 55). The first helical gear 56 and the second helical gear 57 fixed to the output shaft are engaged so that the axial directions are orthogonal to each other.

On the outer peripheral portion of the spool valve 59, annular grooves are formed in the circumferential direction. When the spool valve 59 moves in the direction of the rotation shaft 58 of the pulse motor 60, the annular groove forms a drain oil passage, a main oil passage 50a, a return oil passage 50b, and a communication oil passage (50c, 50d) formed in the first casing. ). When the gear formed on the rotary shaft 58 moves, the main oil passage 50a and the return oil passage 50b are connected to the communication oil passages (50c, 50d).
The rotary shaft 58 is coupled to the drive shaft 61 of the pulse motor 60 and is screw-coupled to the second helical gear 57. Therefore, the second helical gear 57 can move in the direction of the drive shaft 61 by the rotation of the drive shaft 61 of the pulse motor 60 (see, for example, Patent Document 1).
JP 2000-213502 A

  However, in the conventional electrohydraulic motor, the drain oil path is connected to the return oil path without separating the return oil path and the drain oil path. As a result, the pressure oil from the drain oil passage flows into the return oil passage in a high pressure state, so that the pressure in the return oil passage becomes very high and the oil seal provided on the output shaft side of the hydraulic actuator is ruptured. There was a problem that.

  Therefore, an object of the present invention is to provide an electrohydraulic motor that can avoid a return oil passage from becoming extremely high pressure.

  In order to solve the above-described problems, an electrohydraulic motor according to the present invention includes a hydraulic actuator that rotates an output shaft according to the pressure of hydraulic oil, an electric motor that rotates a drive shaft in accordance with an input electric signal, the hydraulic actuator, It is connected to a main oil passage that guides hydraulic oil supplied from the outside and a return oil passage that guides hydraulic oil from the hydraulic actuator to the outside, and responds to the rotation of the drive shaft, thereby the hydraulic actuator and the main oil passage A spool valve that switches connection between the oil passage and the return oil passage, a first toothed shaft that is connected to the spool valve, and a gear that is connected to the output shaft and orthogonal to the first toothed shaft A second toothed shaft and a separation wall provided so as to surround the second toothed shaft. In the electrohydraulic motor according to the present invention, the second toothed shaft side of the separation wall is a drain oil passage, and the opposite side of the separation wall from the second toothed shaft side is a return oil passage. It is characterized by that.

  With this configuration, the pressure oil from the drain oil passage does not flow into the return oil passage in the high pressure state, so the pressure in the return oil passage does not become very high and is provided on the output shaft side of the hydraulic actuator. It is possible to avoid the ruptured oil seal. In addition, the electrohydraulic motor according to the present invention can be applied to a series circuit in which hydraulic actuators are connected in series, an HST (Hydrostatic Transmission) circuit that controls the hydraulic actuator with a discharge amount of a pump, and the like.

  In the present invention, since the pressure oil from the drain oil passage does not flow into the return oil passage in a high pressure state, the pressure in the return oil passage does not become very high and is provided on the output shaft side of the hydraulic actuator. It is possible to avoid the ruptured oil seal.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
1 to 3 show an embodiment of an electrohydraulic motor according to the present invention.
1 to 3, the electrohydraulic motor according to the present invention has a cup-shaped first housing 11 and a second housing 12 fastened and fixed to the first housing 11 with bolts. ing. The first casing 11 is formed with a main oil passage 11a, a return oil passage 11b, a drain oil passage 11e, and communication oil passages (11c, 11d). The output shaft 21 is rotatably supported by the first housing 11 and the second housing 12 by bearings (22, 23), and is urged to one end side of the output shaft 21 by a spring 24. One end portion of the output shaft 21 protruding to the outside of the second housing 12 is connected to driving units of an external device (not shown), and rotational force is transmitted to these driving units.

  The valve plate 13 is fixed to the side wall of the first housing 11 on the other end side of the output shaft 21, and the output shaft 21 is inserted through the central portion of the valve plate 13. The valve plate 13 is formed with concentric arc holes communicating with the communicating oil passages (11 c, 11 d), and hydraulic oil is supplied to and discharged from the pressure chamber 26 in the cylinder block 25 through the arc holes.

  The cylinder block 25 is fixed to the peripheral portion of the output shaft 21. The cylinder block 25 arranges a plurality of pressure chambers 26 having an axis parallel to the output shaft 21 at equal intervals in the circumferential direction. The pressure chamber 26 is provided therein with a piston 27 that slides in the axial direction, and the piston 27 reciprocates by supplying and discharging hydraulic oil.

  A swash plate 28 that is inclined so as to form a predetermined angle with the output shaft 21 inserted through the center portion is formed on the inner wall of the second housing 12. A shoe member 29 is movably engaged with the tip of the piston 27, and the tip presses the inclined surface via the shoe member 29. When the tip portion presses the slope, the shoe member 29 slides on the swash plate 28, and the cylinder block 25 rotates with the output shaft 21 while sliding with the valve plate 13.

  The first helical gear 41 constituting the first toothed shaft is engaged with the second helical gear 42 constituting the second toothed shaft so that the axial directions thereof are orthogonal to each other. Both ends of the first helical gear 41 and the spool valve 43 are rotatably connected via a bearing 44. One end of the second helical gear 42 is fixed to the output shaft 21 by a connecting member 45, and the other end is rotatably supported by the cap cover 14. In this embodiment, a helical gear is used as the toothed shaft, but the toothed shaft is not limited to this.

  A pulse motor 31 constituting an electric motor is mounted on the outer wall of the first housing 11. The rotary shaft 46 is coupled to the drive shaft 32 of the pulse motor 31 and is screw-coupled to the first helical gear 41. Therefore, the first helical gear 41 can move in the direction of the drive shaft 32 by the rotation of the drive shaft 32 of the pulse motor 31.

  Further, as described above, the first helical gear 41 and the second helical gear 42 are engaged so that their axial directions are orthogonal to each other. When a difference occurs between the rotational speed of the first helical gear 41 and the rotational speed of the second helical gear 42, the first helical gear 41 is screwed with respect to the rotational shaft 46, and the rotational shaft Move in 46 directions. As the first helical gear 41 moves, the spool valve 43 moves in the axial direction, and the opening degree of the annular groove 11f changes.

  An annular groove 11 f is formed in the outer peripheral direction of the spool valve 43. The opening degree of the annular groove 11f is controlled by the movement of the spool valve 43, and the annular groove 11f includes the main oil passage 11a, the return oil passage 11b, and the communication oil passages (11c, 11d) formed in the first casing 11. Communicate with.

  That is, in FIG. 5, when the first helical gear 41 moves in the direction of the pulse motor 31, the main oil passage 11a communicates with the communication oil passage 11d, and the return oil passage 11b communicates with the communication oil passage 11c. On the other hand, when the first helical gear 41 moves in the direction opposite to the pulse motor 31, the main oil passage 11a communicates with the communication oil passage 11c, and the return oil passage 11b communicates with the communication oil passage 11d.

  In addition, when a load is applied to the external device and the rotation speed of the output shaft 21 decreases, the rotation speed of the second helical gear 42 decreases, and the rotation speed of the first helical gear 41 and the second helical gear 42 decrease. There is a difference between the rotational speed of the gear 42. If there is a difference between the rotational speeds of the two, the first helical gear 41 performs a screw motion with respect to the rotation shaft 46 and moves in the direction of the rotation shaft 46. As the first helical gear 41 moves, the spool valve 43 moves in the axial direction, and the opening of the annular groove 11f increases.

  A separation wall 11g is formed in the first housing 11, and the separation wall 11g separates the return oil passage 11b and the second helical gear 42. A drain oil passage 11e is formed on the second helical gear 42 side with the separation wall 11g as a boundary, and the drain oil passage 11e and the return oil passage 11b are separated as shown in FIGS.

  The electrohydraulic motor is provided with a device that operates with pressure oil such as a parking brake (not shown). The pressure oil that operates these devices is discharged to the external tank 710 through the drain oil passage 11e separated from the return oil passage 11b. Therefore, since the pressure in the return oil passage 11b in the high pressure state does not further increase, the oil seal 47 provided on the output shaft 21 side is not damaged by the pressure oil.

  As described above, in the electric hydraulic motor according to the present invention, since the pressure oil from the drain oil passage does not flow into the return oil passage in a high pressure state, the pressure in the return oil passage is extremely high. The electrohydraulic motor used in hydraulic excavators, asphalt finishers, machine tools, cranes, etc. has the effect of avoiding the burst of the oil seal provided on the output shaft side of the hydraulic actuator. More specifically, the present invention is useful as an electrohydraulic motor or the like that can release excess hydraulic oil generated when driving is stopped without using excessive energy.

Sectional drawing which shows one Embodiment of the electrohydraulic motor which concerns on this invention AA sectional view of FIG. BB sectional view of FIG. Sectional view showing a conventional electrohydraulic motor AA sectional view of FIG.

Explanation of symbols

11a Main oil passage 11b Return oil passage 11g Separation wall 21 Output shaft 31 Pulse motor (electric motor)
32 Drive shaft 41 First helical gear (first toothed shaft)
42 Second helical gear (second toothed shaft)
43 Spool valve

Claims (1)

A hydraulic actuator that rotates the output shaft by the pressure of hydraulic oil;
An electric motor that rotates a drive shaft in accordance with an input electric signal;
The hydraulic actuator is connected to the hydraulic oil, a main oil path that guides hydraulic oil supplied from the outside, and a return oil path that guides hydraulic oil from the hydraulic actuator to the outside and responds to the rotation of the drive shaft, thereby And a spool valve that switches connection between the main oil passage and the return oil passage,
A first toothed shaft coupled to the spool valve;
A second toothed shaft coupled to the output shaft and engaged perpendicularly to the first toothed shaft;
A separation wall provided so as to surround the second toothed shaft,
An electrohydraulic motor characterized in that the second toothed shaft side of the separation wall is a drain oil passage, and the opposite side of the separation wall to the second toothed shaft side is a return oil passage.

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