JPH07333Y2 - Release device for hydraulic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a release device for a hydraulic transmission in a vehicle.

(Prior Art) As a hydraulic transmission in a vehicle, one shown in FIG. 6 is considered. That is, in FIG. 6, reference numeral 1 denotes a swash plate type variable displacement hydraulic pump, which is driven by an engine via an input shaft 2. 3 is a hydraulic motor,
It has an output shaft 4, and this hydraulic motor 3 is connected to the hydraulic pump 1 via oil passages 5 and 6 so as to form a closed circuit 7.
8 is a charge pump, 9 and 10 are check valves for charging,
11 and 12 are relief valves for charging. 13, 14 are relief valves, 15 is an oil filter, and 16 is an oil cooler.
Reference numeral 17 denotes an unload valve for short-circuiting the oil passages 5 and 6, which has a solenoid 18 and is operated when the switch 19 is turned on.
18 is excited to open the unload valve 17.

In this type of mission, when the vehicle is moved after the engine has failed, the hydraulic pump 1 and the hydraulic motor 3 serve as loads to exert a braking action. Therefore, at this time, switch 19 is turned on, and the unload valve 17
The short circuit between 5 and 6 prevents the braking action.

(Problems to be solved by the invention) However, this has a drawback in that a solenoid valve must be used as the unload valve 17, which increases the manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the related art, and an object of the present invention is to make it possible to easily carry out the operation by utilizing a check valve already provided in the related art.

(Means for Solving the Problems) As a means for solving the problems, the present invention constitutes a closed circuit 7 with the hydraulic pump 1 and the hydraulic motor 3, and further includes a charge pump 8
In the hydraulic transmission in which the closed circuit 7 is charged with oil via the check valves 9 and 10, the valve bodies 26 and 27 of the check valves 9 and 10 are arranged to face each other on the same axis. An operation member 40 for opening and closing the valve bodies 26, 27 is provided between the valve bodies 26, 27.

(Operation) When the head 43 of the operation member 40 is pushed, the valve bodies 26, 27 of the pair of check valves 9, 10 are pushed left and right by the operation member 40, so that the check valves 9, 10 are opened. Therefore, the oil passages 5 and 6 are communicated via the check valves 9 and 10 and short-circuited.

(Embodiment) Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. In addition,
The same names as those in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 1, reference numeral 20 is a port block, in which oil passages 5 and 6 for connecting the hydraulic pump 1 and the hydraulic motor 3 to the closed circuit 7 are formed, and check valves 9 and 10 and others are incorporated. . Check valves 9 and 10 are oil passage 21 to port block 20.
Valve accommodating portions 22 and 2 formed on the same axis and facing each other
Each of the check valves 9 and 10 is housed inside the valve 3, and has valve bodies 26 and 27 that can be brought into and out of contact with the valve seats 24 and 25. Valve compartment 2
2 and 23 are oil passages 30 and 31 of the hydraulic pump 1 through oil passages 28 and 29.
In addition, the oil passage 21 is connected to the discharge side of the charge pump 8 from the oil passage 32 in the direction orthogonal to this through the oil passage 33. Disc
26 and 27 are biased in the closing direction by springs 36 and 37 interposed between blind plugs 34 and 35. Further, the valve bodies 26, 27 have projecting portions 38, 39 at their tips, and the operating member 40 is arranged so as to oppose between the pair of projecting portions 38, 39. The operating member 40 is rod-shaped and is inserted into a guide cylinder 42 screwed to fasten the collar 41 on the port block 20, and a head 43 at the upper end thereof projects upward from the guide cylinder 42. The operating member 40 is a spring 44
When the head portion 43 is pushed downward against the spring 44, the valve body 26, 27 enters between the protrusions 38, 39 to open the valve bodies 26, 27 in the opening direction. It is designed to push it apart. Therefore, in this case, the unload valve 17 between the oil passages 5 and 6 is unnecessary as shown in FIG.

In the above configuration, when charging the closed circuit 7 with oil, normally, one of the check valves 9 and 10 on the low pressure side opens,
From the charge pump 8 to the oil passages 33, 32, 21, the check valve 9 or
Send oil through 10.

When moving the vehicle due to engine failure, etc., the operating member 40
The head 43 of the is pushed downward against the spring 44. Then the operation member
40 enters between the protrusions 38, 39 of the pair of valve bodies 26, 27, and each valve body 2
Push 6,27 against springs 36,37 in the opening direction. Therefore, the valve bodies 26 and 27 slide as shown in FIG. 3, and the check valves 9 and 10 are opened, so that the oil passages 5 and 6 communicate with each other and the hydraulic pump 1 operates. The oil is hydraulic motor 3
The brake action is prevented.

(Effect of the Invention) According to the present invention, the valve members 26, 27 of the pair of check valves 9, 10 are opened by the operating member 40, and the hydraulic motor 3 is short-circuited via the check valves 9, 10. Therefore, there is an advantage that it is simpler than the conventional one and can be implemented at an extremely low cost.

(Other Disclosure) FIG. 4 shows a detector 48 for detecting the swash plate angle of the hydraulic pump 1 while providing electromagnetic unload valves 46, 47 between the oil passages 5, 6.
Is provided to open the unload valves 46 and 47 via the control circuit 49 by the signal from the detector 48 when the hydraulic pump 1 is in the neutral region so that the oil does not flow to the hydraulic motor 3 side. is there.

The detector 48 may be attached to the pedal shaft of the forward / reverse pedal.

In this case, when the hydraulic pump 1 is in the neutral region, the unload valves 46 and 47 are opened, so that the vehicle can be stopped reliably. The neutral area to be stopped may be adjusted by the control circuit 49.

FIG. 5 shows that the detector 51 interlocked with the movement of the forward / reverse pedal 50 detects the neutral region of the hydraulic pump 1, and the control circuit 52 and the solenoid valve 53.
The hydraulic clutch 54 is disengaged via the so that the hydraulic pump 1 does not move in the neutral region. Therefore, there is an advantage that loss of power can be prevented. The oil to the hydraulic clutch 54 is supplied from the charge pump 8.

[Brief description of drawings]

1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram thereof, FIG. 3 is an explanatory view of the same action, and FIGS. 4 and 5 are configuration diagrams showing disclosures other than the present invention. , FIG. 6 is a hydraulic circuit diagram showing a conventional example. 1 ... hydraulic pump, 3 ... hydraulic motor, 7 ... closed circuit,
8 ... Charge pump, 9,10 ... Check valve, 20 ... Port block, 26,27 ... Valve element, 40 ... Operating member.

Claims (1)

[Scope of utility model registration request] 1. A closed circuit 7 comprising a hydraulic pump 1 and a hydraulic motor 3.
And check valves 9 and 10 by the charge pump 8.
In the hydraulic transmission in which the closed circuit 7 is charged with oil via the valve, the valve bodies of the check valves 9 and 10 are
Release of a hydraulic transmission characterized in that 26 and 27 are arranged on the same axis so as to face each other, and an operating member 40 that opens and closes the valve bodies 26 and 27 is provided between the valve bodies 26 and 27. apparatus.