JP2004332858A - Drain mechanism of hydraulic power transmission joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission joint in which torque is not reduced even if an oil temperature reaches a specified value. <P>SOLUTION: A small diameter orifice 52 is formed at the tip of a conical restriction part 51. When the temperature of oil is equal to or lower than a specified temperature, the oil freely passes through the orifice 52 and a torque coping with to a flow resistance produced according to a differential rotational speed is obtained. When the temperature of oil reaches a specified temperature, a thermo switch 57 is operated to press a plunger 55 and a head part 55b closes the orifice 52 to interrupt the oil flow passage so as to maximize the flow resistance of the orifice 52. Since an input shaft and an output shaft are locked and the rotation of the input shaft is transmitted to the output shaft without being disturbed, even if the temperature is increased, the torque is not decreased. Since the input shaft is locked to the output shaft, a friction does not occur at the plunger, and the temperature of the oil is not also increased to a specified value or higher. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drain mechanism of a hydraulic power transmission coupling in which a torque transmitted from an input shaft to an output shaft changes depending on road surface conditions.
[0002]
[Prior art]
Even when an automobile having a 4WD drive mechanism travels on a flat road, it is only necessary to drive one of the drive wheels on a flat road as in normal 2WD driving. When a large torque is required, it is more economical to transmit the required torque to the other drive wheel as well.
[0003]
For this reason, the applicant of the present application has proposed a hydraulic power transmission coupling device in, for example, JP-A-2000-320451. FIG. 4 is an explanatory view of the principle, in which a torque transmission unit 202 and a power transmission joint 204 including a safety device 203 are provided between an input shaft 200 and an output shaft 201. As shown, a torque corresponding to the square of the operating speed at the time of the input shaft 200 and the output time 201 is obtained, and when a large torque is required on a rough road or a slope, the desired torque is transmitted. I have to.
[0004]
However, if the high torque continues, the oil temperature rises, and if the oil temperature rises above a predetermined temperature, the oil drain mechanism is operated by the safety device 203 to protect the joint, and the torque transmitted by the torque transmission unit 202 is reduced. Thus, the oil temperature is prevented from rising.
[0005]
FIG. 6 is a sectional view of a safety device used in a conventional device, and shows a state before a predetermined temperature is reached. 6, the valve block 27 rotates according to the rotation of the rotor that rotates integrally with the output shaft 201. A storage chamber 50 is formed in the valve block 27, a screw portion 51 is formed in the storage chamber 50, and a switch plug 52 is screwed therein.
[0006]
A needle bearing seat 53 to be described later is formed at the upper end of the valve block 27, a fixing pin 54 is inserted from the seat 53 to the storage chamber 50, and the needle bearing to be described later is fixed as a stopper. I have. A metal limiter plug 55 is inserted into the storage chamber 50, and the limiter plug 55 has a substantially U-shaped cross section when viewed in the axial direction.
[0007]
The limiter plug 55 has a communication hole 56 communicating with the high pressure side. The communication hole 56 is formed to have a small diameter so that a high pressure can be set. A limiter pin 60 is housed in the limiter plug 55 so as to be openable and closable with respect to the communication hole 56, and has a projection 61 for opening and closing the communication hole 56.
[0008]
The projection 61 is formed in a cone shape with a substantially triangular cross section, and the tapered portion of the projection 61 contacts the opening end of the communication hole 56. The opposite side of the protrusion 61 of the limiter pin 60 is opened, and a concave portion 63 is formed as shown in FIG. 8 which is a cross section taken along the line VIII-VIII in FIG. The fixing pin 54 is provided through the concave portion 63 of the limiter pin 60, and when the limiter pin 60 moves to open the communication hole 56, the bottom of the concave portion 63 contacts the fixing pin 54, and the movement of the limiter pin 60 is restricted. It has become so.
[0009]
Referring again to FIG. 6, a drain hole 64 (FIG. 8) formed in the limiter plug 55 opens in the drain chamber 64 in which the limiter pin 60 is housed in the limiter plug 55, and the discharge hole 59 is formed in the valve block 27. The drain passage 65 communicates with the drain passage 65. The oil that has passed through the communication hole 56 enters the drain passage 65 through the drain chamber 64 and the discharge hole 59, and is then drained to the low-pressure chamber.
[0010]
A low-pressure chamber 66 is formed on the right side of the switch plug 52, and a thermoswitch 67 is movably housed in the low-pressure chamber 66. A step portion 68 is formed on the outer periphery of the rear portion of the thermo switch 67, a return spring 69 is interposed between the step portion 68 and the switch plug 52, and between the bottom portion of the thermo switch 67 and the switch plug 52. Also, a return spring 70 is interposed.
[0011]
The thermoswitch 67 is urged by the return springs 69 and 70 to press the limiter pin 60 leftward to close the communication hole 56. A head pin 71 protrudes from the center of the distal end of the thermoswitch 67, and a small gap is maintained between the head pin 71 and the fixed pin 54 before the operation within a predetermined temperature. When a predetermined temperature is reached, the head pin 71 extends and hits the fixed pin 54, and the reaction force causes the thermoswitch 67 to move backward to the right against the return springs 69 and 70, and the limiter pin 60 moves to the right by high pressure from the high pressure side. In the direction to open the communication hole 56.
[0012]
When the torque exceeds a predetermined value, the limiter pin 60 moves rightward against the return springs 69 and 70 due to the high pressure acting on the limiter pin 60 through the communication hole 56, and gradually opens the communication hole 56. At the bottom of the storage chamber 50 formed in the valve block 27, a drain plug 72 is disposed following the limiter plug 55, and a drain hole 73 is formed at the tip of the drain plug 72.
[0013]
A drain pin 75 urged by a drain spring 74 is slidably housed in the drain plug 72. A first high-pressure chamber 76 is formed inside the drain pin 75. The first high-pressure chamber 76 communicates with the drain chamber 64 of the limiter plug 55 through the communication hole 56, and a through-hole formed at the distal end. It communicates with a second high-pressure chamber 78 formed in the valve block 27 via 77. A drain spring 74 is interposed in the first high-pressure chamber 76, and one end of the drain spring 74 is locked to the inner wall of the through hole 77 of the drain pin 75, and the other end is locked to the limiter plug 55.
[0014]
An oil seal 79 is mounted between the drain pin 75 and the drain plug 72, and an orifice 80 is formed in the drain pin 75. The orifice 80 communicates with a drain chamber 81 formed between the drain plug 72 and the drain pin 75 and a first high-pressure chamber 76 inside the drain pin 75, and due to the flow resistance when oil passes through the orifice 80. A reaction force is generated in a plunger described later to transmit torque between the housing and the rotor. The drain chamber 81 communicates with a drain passage 82, and the oil that has entered the drain chamber 81 is drained from the drain passage 82 to a low-pressure chamber. In addition, 87a and 87b are aluminum washers for preventing leakage.
[0015]
When the oil reaches a predetermined temperature, as shown in FIG. 7, the head pin 71 of the thermo switch 67 is operated by extension, and the thermo switch 67 is moved rightward by pressing against the fixing pin 54 to make the limiter pin 60 free. . Therefore, the communication hole 56 is opened by the limiter pin 60 moving backward against the oil pressure in the first high-pressure chamber 76. For this reason, the hydraulic pressure of the first high-pressure chamber 76 of the drain pin 75 decreases at a stretch, and the hydraulic pressure of the second high-pressure chamber 78 exceeds the spring force of the drain spring 74, whereby the drain pin 75 retreats and opens the drain hole 73, Drain the oil.
[0016]
On the other hand, when the predetermined torque is reached in a state where the thermoswitch is not operated, the hydraulic pressure of the first high-pressure chamber 76 becomes larger than the spring force of the return springs 69 and 70, and the limiter pin 60 opens the communication hole 56 to regulate the pressure. The balance between the force obtained by adding the spring force of the drain spring 74 to the hydraulic pressure of the first high-pressure chamber 76 and the hydraulic pressure of the second high-pressure chamber 78 changes, and the drain pin 75 itself gradually balances with the hydraulic pressure. The hole 73 is opened, and the oil in the second high-pressure chamber is drained to regulate the pressure.
[0017]
The second high pressure chamber 78 communicates with a high pressure port 86 via three high pressure paths 83, 84, 85. Oil is supplied from the high-pressure port 86 to the second high-pressure chamber 78 through the high-pressure passages 83, 84, and 85 as indicated by an arrow D.
[0018]
Next, the operation will be described. In a normal state where the temperature applied to the thermoswitch 67 does not reach the predetermined temperature, the hydraulic pressure is supplied from the high pressure port 86 to the second high pressure chamber 78 through the high pressure paths 83, 84 and 85 as shown by the arrow D. The oil in the second high-pressure chamber 78 enters the first high-pressure chamber 76 through the through hole 77 of the drain pin 75, and is further released through the orifice 80 to the drain chamber 81. Therefore, the hydraulic pressures of the first high-pressure chamber 76 and the second high-pressure chamber 78 are the same.
[0019]
The return springs 69, 70 press the limiter pin 60 via the thermoswitch 67, the spring force of the return springs 69, 70 exceeds the hydraulic pressure of the first high-pressure chamber 76, and the limiter pin 60 is connected to the communication hole 56. Is closed. In addition, the drain pin 75 is urged leftward by a hydraulic reaction force of the drain spring 74 and the first high-pressure chamber 76 to close the drain hole 73. Therefore, the hydraulic pressure is sealed.
[0020]
On the other hand, the hydraulic pressure that has entered the first high-pressure chamber 76 is drained from the drain chamber 81 through the orifice 80 to the low-pressure chamber via the drain passage 82 as shown by an arrow C. As the torque characteristic at the normal time, as shown by the characteristic A in FIG. 5, a torque ΔT proportional to the square of the differential rotation speed ΔN is obtained. When the temperature applied to the thermo switch 67 reaches a predetermined temperature, the head pin 71 of the thermo switch 67 extends leftward as shown in FIG. 7 and hits the fixed pin 54, and the reaction force of the head pin 71 as shown in FIG. 67 moves backward in the right direction against the return springs 69 and 70. For this reason, the force pressing the limiter pin 60 is cut, and the limiter pin 60 is forcibly relieved.
[0021]
When the limiter pin 60 retreats and opens the communication hole 56, the oil pressure in the drain chamber 64 is drained from the drain passage 65 to the low-pressure chamber 66, and the oil pressure in the first high-pressure chamber 76 of the drain pin 75 drops at a stroke. For this reason, the drain pin 75 retreats and opens the drain hole 73 by the hydraulic pressure of the second high-pressure chamber 78 which exceeds the spring force of the drain spring 74, and drains the oil. The torque characteristic at this time is shown in FIG.
As shown in the characteristic B, the torque hardly disappears, and the torque ΔT does not increase as the differential rotation speed ΔN increases.
[0022]
Next, when a predetermined torque is reached before the thermoswitch is activated, the balance between the oil pressure in the first high-pressure chamber 76 and the springs of the return springs 69 and 70 changes, and the first high-pressure acting on the limiter pin 60 is changed. The hydraulic pressure in the chamber 76 exceeds the spring force of the return springs 69, 70, and the limiter pin 60 opens the communication hole 56 and regulates the pressure so as to maintain a balance. For this reason, the balance between the force obtained by adding the spring force of the drain spring 74 to the oil pressure in the first high-pressure chamber 76 and the oil pressure in the second high-pressure chamber 78 changes. In this case, the hydraulic pressure in the second high-pressure chamber 78 exceeds the hydraulic pressure in the first high-pressure chamber 76 plus the spring force of the drain spring 74, and the drain pin 75 gradually opens the drain hole 73. In this way, the drain pin 75 itself drains the oil while gradually balancing the hydraulic pressure. At this time, the torque characteristic can be kept constant when the torque is equal to or more than the predetermined torque ΔT1, as shown by the characteristic C in FIG. As described above, the drain pin 75 itself operates in a hydraulic balance, and can maintain the torque ΔT at a constant value. In addition, the shift mechanism from 4WD to 2WD according to the temperature and the torque limiter mechanism are also used, and the function of the torque limiter is also provided. Can have.
[0023]
[Patent Document]
Japanese Patent Application No. 2000-320577
[0024]
[Problems to be solved by the invention]
However, in such a conventional device, when the oil temperature rises above a predetermined value, the oil drain mechanism, which is a safety device for protecting the joint, operates. There is a problem that the required temperature cannot be obtained because the safety device operates even though the torque is required when the oil temperature rises.
[0025]
For this reason, the present invention is such that the torque does not decrease even if the oil temperature increases, and the joint can be protected.
[0026]
[Means for Solving the Problems]
In order to solve such a problem, the present invention is directed to a drain mechanism of a hydraulic power transmission joint that is provided between an input shaft and an output shaft that are rotatable relative to each other, and that transmits torque according to a rotational speed difference between the two shafts. Target.
[0027]
In such a device, the present invention includes an orifice that generates a flow resistance corresponding to an oil flow rate caused by a rotation speed difference, and a head pin that is provided by being biased by a spring in a low-pressure chamber in a valve block and that projects when a predetermined temperature is reached. A thermoswitch provided with a plunger that is slidably provided in the valve block and is urged by a spring to open an orifice communicating with the high-pressure chamber, and when a predetermined temperature is reached, pressed by a protruding head pin to close the orifice. Characterized by the following.
[0028]
In the device configured as described above, during normal operation, the oil flow rate increases as the differential rotation speed between the input shaft and the output shaft increases, and the reaction force due to the flow resistance of the oil when passing through the orifice is applied to the torque transmission unit. The transmitted torque corresponding to the magnitude of the reaction force is transmitted. When the oil temperature exceeds a predetermined value, the thermoswitch operates to close the orifice, so that the rotation difference between the input shaft and the output shaft becomes almost zero, and all the torque of the input shaft is transmitted to the output shaft. In addition, since the rotation difference is almost zero, no heat energy is generated, and a rise in the temperature of the coupling oil can be prevented.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a sectional view showing a hydraulic power transmission mechanism in which a drain mechanism of the present invention is used. A companion flange 1 is connected to a propeller shaft (not shown) serving as a front wheel drive shaft. Are inserted and splined. On the right side of the cam housing shaft 2, there is provided a disk-shaped cam surface 9 which rotates integrally with the cam housing shaft 2, and, for example, four peaks are provided radially from the center of the cam surface. The plunger 16 housed in the rotor 12 is engaged with the first arm. Therefore, in this example, the plunger chambers 15 are provided at nine positions around the shaft portion. A valve block 27 is provided on the right side of the plunger chamber 15, and the valve block 27 accommodates the drain mechanism of the present invention, which is a joint protection device.
[0030]
FIG. 2 is a cross-sectional view of the drain mechanism. FIG. 2A shows a state before the oil reaches a predetermined temperature, and FIG. 2B shows a state when the oil reaches a predetermined temperature. 2, a concave portion 27a is provided on the left end of the valve block 27 as shown in FIG. 3, and a hole is formed from the concave portion 27a toward the center, and a part of the hole is formed in the first storage chamber. The second storage chamber 50b is formed halfway through the hole so as to have a larger diameter.
[0031]
Returning to FIG. 2, the right side of the first storage chamber 50 a forms a restricting portion 51 narrowed in a conical shape, and the right end of the restricting portion 51 communicates with the high-pressure passage 53 through a small-diameter orifice 52. The high pressure passage 53 communicates with the high pressure chamber 28 of FIG.
[0032]
A plunger 55 having a conical right end at the right end is inserted into a spring 56 and mounted in the first storage chamber 50a and urged to the left. A thermo switch 57 is mounted in the second storage chamber 50b via a spring 58. It is inserted and mounted and biased to the right. A concave portion 55a is formed in the left end of the plunger 55, and the head pin 71 of the thermoswitch 57 contacts the concave portion 55a. The left end of the spring 58 is engaged with a spring stopper 62 embedded in the valve block 27. Further, a drain passage 64 is formed in the first storage chamber 50a, and communicates with the low-pressure chamber 19 in FIG.
[0033]
Referring again to FIG. 1, a front bearing 3 is provided on the outer periphery of the cam housing shaft 2, and the cam housing shaft 2 is supported by the differential case 4 via the front bearing 3. A seal member 5 and a cover 6 are provided between the differential case 4 and the companion flange 1. The seal member 5 and the cover 6 prevent foreign substances such as dust from entering and outflow of the differential oil.
[0034]
A housing 8 is fixed to the left side of the cam housing shaft portion 2 by a welded portion 7, and a cam surface 9 is formed on the inner surface. Also, plugs 10 and 11 for inserting or discharging oil into the joint are inserted into the cam housing shaft portion 2. A rotor 12 is rotatably housed in the housing 8. The rotor 12 is engaged with the main shaft 13 and rotates integrally with the main shaft 13.
[0035]
A drive pinion gear 14 of a rear differential is inserted and fixed in the main shaft 13 from the right side, and transmits drive torque to rear wheels via the rear differential. A plunger chamber 15 is formed in the rotor 12, and a plunger 16 is slidably housed in the plunger chamber 15 via a return spring 17. As described above, the rotor 12 is provided with nine plunger chambers 15 around the axis in this example.
[0036]
A plunger 16 is slidably housed in the plunger chamber 15 via a return spring 17. A suction passage 18 is formed on the head side of the plunger 16, and the suction passage 18 communicates with the low-pressure chamber 19. The suction passage 18 and the plunger chamber 15 communicate with each other through a communication hole 20, and the communication hole 20 is opened and closed by a suction one-way valve 21 formed of a ball. A valve seat 22 is formed inside the plunger chamber 15, and a one-way valve 21 is seated on the valve seat 22. A check plug 23 is provided at the step of the valve seat 22, and a check spring (not shown) for pressing and positioning the one-way valve 21 is interposed between the check plug 23 and the one-way valve 21. I have.
[0037]
A return spring 17 is interposed between the check plug 23 and the bottom of the rotor 12. A discharge hole 24 is formed in the rotor 12, and the discharge hole 24 communicates with the plunger chamber 15. The discharge hole 24 is provided with a discharge one-way valve 25 made of a ball. That is, a valve seat 26 is formed in the discharge hole 24, and the one-way valve 25 is seated on the valve seat 26.
[0038]
Subsequent to the rotor 12, a valve block 27 is provided. The valve block 27 has a high-pressure chamber 28 communicating with the discharge hole 24 of the rotor 12. A regulating member 29 protrudes from the high-pressure chamber 28, and the regulating member 29 positions the one-way valve 25 at a predetermined position. The valve block 27 is provided with an orifice member 31 having an orifice, the high-pressure chamber 28 is connected to the high-pressure chamber 54 in FIG. 2, and the drain passage 64 in FIG. 2 communicates with the discharge path of the orifice member 31 in FIG. . The valve block 27 and the rotor 12 are positioned by pins 32 and fixed by bolts 33.
[0039]
When the plunger 16 is in the suction stroke, the one-way valve 21 for suction provided at the head of the plunger 16 is opened, and oil is sucked into the plunger chamber 15 through the low-pressure chamber 19, the suction passage 18, and the communication hole 20. At this time, the one-way valve 25 for discharge provided in the discharge hole 24 of the rotor 12 is closed, and the backflow of oil from the high-pressure chamber 28 is prevented. When the plunger 16 is in the discharge stroke, the discharge-side one-way valve 25 is opened, and the oil in the plunger chamber 15 is supplied from the discharge hole 24 and the high-pressure chamber 28 to the high-pressure chamber 54 provided in the valve block 27.
[0040]
At this time, the one-way valve 21 for suction is closed to prevent oil from leaking from the communication hole 20 and the suction passage 18 to the low-pressure chamber 19. Subsequent to the valve block 27, a bearing retainer 34 is provided. The bearing retainer 34 is press-fitted and fixed to the housing 8 and is positioned by a snap ring 35. The bearing retainer 34 rotates integrally with the housing 8. A through hole 36 is formed in the bearing retainer 34, and the through hole 36 communicates with the low-pressure chamber 19.
[0041]
Needle bearings 37 and 38 are interposed between the bearing retainer 34 and the valve block 27, and between the bearing retainer 34 and the main shaft 13, respectively. An oil seal 39 is provided between the bearing retainer 34 and the main shaft 13, and the oil seal 39 prevents oil from flowing out. An accumulator piston 40 for absorbing thermal expansion and contraction of oil is slidably provided outside the bearing retainer 34, and an accumulator chamber 41 is defined by the accumulator piston 40.
[0042]
The accumulator chamber 41 communicates with the low-pressure chamber 19 through the through hole 36 of the bearing retainer 34. O-rings 42 and 43 for preventing oil leakage are interposed between the accumulator piston 40 and the housing 8 and between the accumulator piston 40 and the bearing retainer 34, respectively. The accumulation retainer 44 has its outer peripheral end fixed to the housing 8.
[0043]
A return spring 45 is interposed between the accumulator retainer 44 and the bottom of the accumulator piston 40. A rear bearing 47 is provided on the outer periphery of the extending portion of the bearing retainer 34, and the bearing retainer 34 is supported by the differential case 4 via the rear bearing 47. Further, a lubricating oil groove 48 and a seal member 49 are provided in the left opening of the main shaft 13.
[0044]
Next, the operation will be described. While traveling on a flat road, the differential rotation of the input shaft 200 and the output shaft 201 is small, so that the suction and discharge of oil in the plunger chamber 15 is slow. That is, although the peak provided on the cam surface 9 of FIG. 1 and the plunger 16 are in contact with each other, since the differential rotation between the input shaft 200 and the output shaft 201 is small, the number of times the plunger 16 climbs over the peak of the cam surface 9 is small. Therefore, the number of reciprocating movements of the plunger 16 is small, and the suction and discharge of oil are slow.
[0045]
The oil sucked into the plunger chamber 15 flows through the path of the one-way valve block 25, the high-pressure chamber 28, the high-pressure chamber 54, the orifice 52, the restricting portion 51, the drain passage 64, and the low-pressure chamber 19 in FIG. When the oil temperature has not reached the predetermined value, the thermo switch 57 is not operated, and is in the state of FIG.
[0046]
At this time, the oil flows through the above-described path, but since the portion of the orifice 52 is narrow, flow resistance occurs. When the differential rotation speed is small, the flow resistance of the oil is small because the flow speed of the oil is low. However, when the differential rotation speed is high and the flow speed of the oil is high, the flow resistance at the orifice 52 increases. Therefore, as shown by the symbol A in FIG. 5, a torque proportional to the square of the differential speed is transmitted. In the example of FIG. 2, the oil temperature does not rise above a predetermined value as described later, so that the temperature 2WD function is not provided.
[0047]
As the differential rotation speed increases, the oil temperature increases due to friction between the cam surface 9 and the plunger 16 in FIG. 1, and when the oil temperature exceeds a predetermined temperature, the thermoswitch 57 operates as shown in FIG. The protrusion 71 moves the plunger 55 rightward in the drawing, so that the leading end 55b of the plunger 55 comes into contact with the restricting portion 51 and closes the orifice 52, so that the oil passage is cut off.
[0048]
The spring 56 returns the plunger 55 to the position shown in FIG. 2A when the oil temperature is equal to or lower than a predetermined value. The internal damage of the switch 57 is prevented.
[0049]
As a result, the flow resistance becomes maximum and the oil in the plunger chamber 15 in FIG. 1 is not discharged, so that the movement of the plunger 16 also stops, and the plunger 16 remains pressed against the cam surface 9. In this state, the rotation of the cam housing shaft 2 is transmitted to the drive pinion gear 14 as it is, so that friction between the plunger 16 and the cam surface 9 does not occur, and no further increase in oil temperature occurs.
[0050]
The present invention is not limited to the above-described embodiment, but includes appropriate modifications without impairing the objects and advantages thereof. Further, the present invention is not limited by the numerical values shown in the above embodiments.
[0051]
【The invention's effect】
As described above, according to the present invention, since the oil flow path is normally secured through the orifice, the oil flow resistance at the orifice corresponds to the differential rotation speed between the input shaft and the output shaft. The torque is generated and transmitted, but the oil temperature rises as the differential rotation speed increases.When the oil temperature exceeds a predetermined value, the thermoswitch operates to close the orifice, and the oil flow Since the path is cut, the flow resistance is maximized, and the rotation of the input shaft is transmitted to the output shaft as it is, so that the differential rotation stops and the oil temperature stops rising. As a result, when the oil temperature rises, the oil is drained in the past, and the torque suddenly became small, which hindered traveling.However, according to the present invention, the oil is drained even if the oil temperature reaches a predetermined value. As a result, the torque does not decrease, and the required torque while traveling on a rough road can be obtained.
[0052]
In addition, since the orifice is closed when the oil temperature reaches a predetermined value, the structure is simpler than the conventional one, and the number of parts is reduced because the structure is simple. Although the precision of each part is strictly controlled to cope with the clogging, the present invention has an effect that the precision of the parts can be easily managed because the number of parts is reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a hydraulic power transmission joint using a drain mechanism of the present invention.
FIG. 2 is a sectional view showing an embodiment of the present invention.
FIG. 3 is a perspective view showing details of a recess 27 in FIG. 2;
FIG. 4 shows the principle of power transmission.
FIG. 5 is a graph showing torque characteristics.
FIG. 6 is a sectional view showing an operation state before an oil temperature reaches a predetermined temperature in a drain mechanism of a conventional example.
FIG. 7 is a cross-sectional view showing an operation state after an oil temperature reaches a predetermined temperature in a conventional drain mechanism.
8 is a sectional view taken along the line VIII-VIII in FIG.
[Explanation of symbols]
1: Companion flange
2: Cam housing shaft
3: Front bearing
4: differential case
5, 49: Seal member
6: Cover
7: weld
8: Housing
9: Cam surface
10, 11: Flag
12: Rotor
13: Main shaft
14: Drive pinion gear
15: Plunger room
16: Plunger
17: Return spring
18: Inhalation path
19: Low pressure chamber
20: Communication hole
21: One-way valve for inhalation
22, 26: Valve seat
23: Check plug
24: discharge hole
25: One-way valve for discharge
27: Valve
28: High pressure chamber
29: regulating member
30: Orifice
31: Orifice member
32: Pin
33: bolt
34: Bearing retainer
35: Snap ring
36: Through hole
37, 38: Needle bearing
39: Oil seal
40: Accumulator piston
41: Accumulator room
42, 43: O-ring
44: Accumulator
45, 46: Return spring
47: Rear bearing
48: Oil groove for lubrication
50, 50a, 50b: storage room
51: Regulatory Department
52: Orifice
53: High-pressure path
54: High pressure chamber
55: Plunger
55a: recess
55b: Tip
56, 58: Spring
57: Thermo switch
59: discharge hole
60: Limiter pin
62: Spring stop
64: Drain passage

Claims (2)

In a drain mechanism of a hydraulic power transmission coupling, which is provided between an input shaft and an output shaft that are relatively rotatable and transmits a torque corresponding to a rotation speed difference between the two shafts.
An orifice that generates a flow resistance corresponding to the oil flow rate generated by the rotation speed difference,
A thermoswitch having a head pin provided in the low-pressure chamber in the valve block and urged by the first spring and protruding when a predetermined temperature is reached;
A plunger that is slidably provided in the valve block and is urged by a second spring to open the orifice, and when a predetermined temperature is reached, is pressed by the protruding head pin to close the orifice. A drain mechanism for a hydraulic power transmission joint. A drain mechanism for a hydraulic power transmission coupling according to claim 1,
Hydraulic power transmission coupling
A housing connected to the input shaft and having a cam surface formed on an inner surface side;
A rotor connected to the output shaft and rotatably housed in the housing and axially defining a plurality of plunger chambers;
A plurality of plungers that are slidably reciprocally slid under the pressure of a return spring in each of the plurality of plunger chambers and driven by the cam surface during relative rotation of the two shafts;
A discharge hole formed in the rotor and communicating with the plunger chamber;
With
The valve block is connected to the rotor, and a reaction force is generated in the plunger by flow resistance when oil discharged by driving the plunger passes through an orifice provided in the valve block, so that torque is generated between the housing and the rotor. A drain mechanism for a hydraulic power transmission joint, characterized by transmitting the power.

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