JP2008116055A - Valve device for preventing shock torque of clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve device for preventing shock torque capable of properly controlling a connection time which is a time from the stepping cancellation of a clutch pedal to the connection of an engine and a transmission irrespective of a change in the viscosity of a working fluid. <P>SOLUTION: When thrust by the differential pressure of the working fluid received by a movable valve element 57 is small since the actual viscosity of the working fluid is low, the movable valve element 57 comes in contact with a fixed valve element 55 and the working fluid is refluxed via a throttle hole 53a with a large diameter and a throttle hole 53b with a small diameter (fully throttled) into a master cylinder 11. When the thrust by the differential pressure of the working fluid received by the movable valve element 57 is large since the actual viscosity of the working fluid is high, the movable valve element does not come in contact with the fixed valve element 55 and the working fluid is refluxed via the throttle hole 53a with the large diameter and a step 62 into the master cylinder 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a valve device for preventing shock torque of a clutch.

  When shifting a vehicle equipped with a manually operated transmission, first depress the clutch pedal to temporarily disconnect the engine and transmission, then operate the shift lever to switch the gear ratio of the transmission gear, Next, a series of operations of releasing the depression of the clutch pedal and returning the connection between the engine and the transmission is performed.

  In addition, the above-described speed change is performed by a mechanism described below. When the clutch pedal is depressed, the hydraulic fluid is discharged from the master cylinder, flows into the release cylinder, and the engine and transmission are disconnected. Further, when the depression of the clutch pedal is released, the hydraulic fluid returns from the release cylinder to the master cylinder, and the engine and the transmission are connected.

  Among these operations, when the difference in the rotational speed between the engine and the transmission rotation shaft is large, such as when starting, if the release of the clutch pedal is quickly performed, the connection between the engine and the transmission is instantaneously established. The shock torque is generated. This clutch shock torque causes engine stoppage, abnormal wear of the clutch, and the like.

  Therefore, conventionally, in order to prevent the above-mentioned shock torque, a shock torque prevention valve for restricting the flow of the hydraulic fluid flowing back from the release cylinder to the master cylinder is arranged on the hydraulic fluid passage between the release cylinder and the master cylinder. The means to install is taken. By taking the above measures, even if the release of the clutch pedal is quickly released, the connection between the engine and the transmission is not made instantaneously, and shock torque can be prevented.

  However, in cold districts, the viscosity of the hydraulic fluid increases as the hydraulic fluid temperature decreases, and the flow rate of the hydraulic fluid passing through the throttle of the shock torque prevention valve decreases. The connection time, which is the time from the release of the depression of the clutch pedal to the connection between the engine and the transmission, becomes longer. On the other hand, the driver feels that the operation performance is better when the connection time is kept substantially constant even when conditions such as temperature change. Therefore, the change in the connection time due to the change in the viscosity of the hydraulic fluid (due to the change in the liquid temperature or the like) is not preferable.

  As a technique for solving the above problem, a technique disclosed in Patent Document 1 shown in FIGS. 8 and 9 is known. This includes a housing 21, a valve member 27 having a throttle communication passage 27 a that forms a throttle by communicating the first chamber 40 and the second chamber 41 in the cylinder space 24, and the valve member 27 with the first chamber 40. The first spring 26 that urges the second chamber 41 in a direction to shut off the second chamber 41 and the second spring 30 that urges the valve member 27 in the opposite direction to the first spring 26 are provided. It is made of a shape memory alloy having a characteristic that the spring constant decreases when the temperature is lower than a predetermined temperature.

  Here, when the second spring 30 exceeds the predetermined temperature, the elastic force from the second spring 30 is larger than the elastic force from the first spring 26 applied to the valve member 27, and the second spring 30 is When the predetermined temperature is not reached, the first spring 26 and the second spring 30 are selected so that the elastic force from the first spring 26 is larger than the elastic force from the second spring 30 applied to the valve member 27. Yes.

  According to this shock torque prevention valve, when the hydraulic fluid recirculated from the release cylinder 12 to the master cylinder 11 exceeds the predetermined temperature and at the same time the second spring 30 also exceeds the predetermined temperature, the second spring 30 Since the elastic force of the first spring 26 is larger than the elastic force of the first spring 26, the valve member 27 is in a position where the first chamber 40 and the second chamber 41 are blocked (referred to as a valve-closed position) as shown in FIG. The hydraulic fluid is squeezed from the first chamber 40 by the throttle communication passage 27a and flows to the second chamber 41. On the other hand, when the hydraulic fluid returning from the release cylinder 12 to the master cylinder 11 does not reach the predetermined temperature and at the same time the second spring 30 does not reach the predetermined temperature, the elastic force of the second spring 30 is the elasticity of the first spring 26. 9, the valve member 27 is in a position where the first chamber 40 and the second chamber 41 are not blocked (referred to as a valve opening position) as shown in FIG. It flows into the second chamber 41 without being squeezed through the gap between the seat portion 28 and the valve member 27.

Thus, when the hydraulic fluid exceeds the predetermined temperature, the hydraulic fluid is throttled by the throttle communication passage 27a and returned from the second chamber 41 to the first chamber 40, so that the shock torque is prevented. When the liquid does not reach the predetermined temperature, the hydraulic fluid is hardly squeezed and returns from the second chamber 41 to the first chamber 40, thereby preventing an increase in connection time due to an increase in the viscosity of the hydraulic fluid.
JP-A-6-330961

  As shown in FIG. 4, the viscosity of the hydraulic fluid has a characteristic that it rapidly increases when the temperature of the hydraulic fluid falls below a certain temperature (referred to as viscosity change temperature). The value varies depending on the type of oil and the nature of the dirt. On the other hand, in the shock torque preventing valve device disclosed in Patent Document 1, regardless of the actual viscosity of the hydraulic fluid, when the temperature of the hydraulic fluid becomes lower than the predetermined temperature, Since the elastic force is lowered and the valve is opened (that is, the valve opening timing is governed only by the temperature of the hydraulic fluid), if the predetermined temperature does not substantially match the viscosity change temperature, the fluid temperature of the hydraulic fluid The connection time is changed due to the change of. That is, when the predetermined temperature is higher than the viscosity change temperature, the hydraulic fluid passes through without being squeezed at a liquid temperature equal to or lower than the predetermined temperature and equal to or higher than the viscosity change temperature, The connection time may become excessively short and shock torque may be generated. On the other hand, when the predetermined temperature is lower than the viscosity change temperature, the hydraulic fluid is squeezed through at a liquid temperature that is higher than the predetermined temperature and lower than the viscosity change temperature even though the hydraulic fluid is high in viscosity. The connection time becomes excessively long, and the operation performance decreases. In other words, this shock torque preventing valve device functions well only in the case of hydraulic fluid having a specific temperature-viscosity characteristic.

  The present invention has been made in view of the above problems, and shock torque that can properly control the connection time, which is the time from the release of the depression of the clutch pedal to the connection between the engine and the transmission, regardless of the change in the viscosity of the hydraulic fluid. It aims at providing the valve apparatus for prevention.

  The invention according to claim 1 is disposed on a passage of hydraulic fluid between a master cylinder operated by a clutch pedal and a release cylinder that moves a clutch by hydraulic pressure of the hydraulic fluid, from the release cylinder to the master cylinder. A shock torque prevention valve device for preventing shock torque of the clutch by restricting the flow rate of the recirculating working fluid, comprising an inner hole, a large-diameter throttle hole for restricting the flow of the working fluid, and a fixed valve body. A valve body having a small-diameter throttle hole for restricting the flow of hydraulic fluid, and a movable valve body housed in an inner hole of the valve body so as to be slidable in a direction to come in contact with and separate from the fixed valve body, A pressure loss of the hydraulic fluid in the small-diameter throttle hole, comprising a spring that urges the movable valve body toward the fixed valve body by elastic force and reduces the elastic force when the temperature decreases. When the pressing force that urges the movable valve body away from the fixed valve body is caused by the differential pressure due to the pressure, and the elastic force is larger than the pressing force, the movable valve body abuts on the fixed valve body, When the hydraulic fluid passage is limited to the small-diameter throttle hole, and the elastic force is smaller than the pressing force, the movable valve body is separated from the fixed valve body and the hydraulic fluid flows through the gap, and the large-diameter throttle hole. The shock torque preventing valve device is characterized in that the flow of hydraulic fluid is limited by the above.

  According to the above configuration, when the temperature of the hydraulic fluid is high, the elastic force is sufficiently large, so that the movable valve body is reliably brought into contact with the fixed valve body (closed), and the shock torque is reliably prevented. . On the other hand, since the elastic force decreases when the temperature is low, the valve opening timing is determined by a balance between the elastic force and the pressing force due to the differential pressure of the hydraulic fluid in the small diameter throttle hole. That is, when the actual viscosity of the hydraulic fluid increases, the pressing force due to the pressure loss increases, and the valve opens when the pressing force exceeds the elastic force. Accordingly, when the hydraulic fluid is hot, shock torque is reliably prevented, while when the hydraulic fluid is low, the valve is opened or closed (ie, a large-diameter throttle hole) at an appropriate timing commensurate with the actual viscosity of the hydraulic fluid. And the small-diameter throttle hole), the change in the connection time, which is the time from the release of the depression of the clutch pedal to the connection between the engine and the transmission, is suppressed.

  The invention according to claim 2 is the valve device for shock torque prevention according to claim 1, wherein the movable valve body includes a cross-sectional area of the large-diameter throttle hole and a cross-sectional area of the small-diameter throttle hole. The above-mentioned pressing force works with the difference in pressure as the pressure receiving area. According to the above configuration, the movable valve body has the pressure receiving surface whose pressure receiving area is the difference between the cross-sectional area of the large-diameter throttle hole and the cross-sectional area of the small-diameter throttle hole. A structure for applying a pressing force for urging the movable valve body in the opposite direction to the fixed valve body can be easily realized by the pressure loss of the hydraulic fluid.

  A third aspect of the present invention is the valve device for shock torque prevention according to the first or second aspect, wherein the hydraulic fluid is a passage from the master cylinder to the release cylinder, and the small diameter throttle hole for the hydraulic fluid. Alternatively, the flow of the hydraulic fluid from the release cylinder to the master cylinder is permitted by allowing the flow of the hydraulic fluid from the master cylinder to the release cylinder on a passage other than the passage passing through the large-diameter throttle hole. A check valve for blocking is provided. According to the above configuration, since the hydraulic fluid is provided from the master cylinder to the release cylinder, the hydraulic fluid flows from the release cylinder to the master cylinder. The check valve need not be provided separately from the shock torque preventing valve device.

  A fourth aspect of the present invention is the shock torque preventing valve device according to any one of the first to third aspects, wherein the spring is made of a shape memory alloy. According to said structure, the spring from which the said elastic force reduces is easily implement | achieved when temperature falls.

  According to the first aspect of the present invention, when the hydraulic fluid is at a high temperature, the shock torque is reliably prevented, while when the hydraulic fluid is at a low temperature, the valve is opened or closed at an appropriate timing corresponding to the actual viscosity of the hydraulic fluid. A valve (that is, throttle switching) is performed, and the change in the connection time, which is the time from the release of the depression of the clutch pedal to the connection between the engine and the transmission, is suppressed.

  According to the second aspect of the present invention, it is possible to easily realize a structure that applies a pressing force that urges the movable valve body in the opposite direction to the fixed valve body due to the pressure loss of the hydraulic fluid caused by the small-diameter throttle hole. According to the third aspect of the present invention, there is no need to dispose the check valve separately from the shock torque preventing valve device. According to the fourth aspect of the present invention, a spring in which the elastic force decreases as the temperature decreases can be easily realized.

  1 and 2 are front sectional views of a shock torque preventing valve device to which the present invention is applied, and FIG. 3 is a front sectional view and a side view of a movable valve body. 1 shows a state in which the movable valve body 57 and the fixed valve body 55 are in contact with each other, and FIG. 2 shows a state in which the movable valve body 57 and the fixed valve body 55 are separated from each other. The operation of the clutch pedal 10 is transmitted to the master cylinder 11 connected thereto, and the hydraulic fluid sent from the master cylinder 11 flows into the release cylinder 12 via the shock torque preventing valve device 20. One end of the output rod 12a of the release cylinder 12 is connected to the other end of a release fork 13 connected to a clutch (not shown).

  The shock torque preventing valve device 20 is disposed on the hydraulic fluid passage between the master cylinder 11 and the release cylinder 12, and includes a main body 51 provided with a port 52b and an inner hole 50, and a large diameter. A movable valve having a fixed valve body 55 having a throttle hole 53a and a check valve 54, and a small-diameter throttle hole 53b slidably housed in the inner hole 50 in a direction to be separated from and in contact with the fixed valve body 55. A body 57 and a plug 59 having a port 52a and pressing and fixing the fixed valve body 55 to the main body 51 are provided. The check valve 54 is made of an elastic material such as rubber, and is provided in the fixed valve body 55 so as to close the valve hole 55a provided separately from the large-diameter throttle hole 53a. The pressure of the working fluid flowing in the cylinder 12 causes the port 52a side (right side in FIG. 1) to bend and deform to open the valve hole 55a. Accordingly, the operation of the check valve 54 allows the flow of hydraulic fluid from the master cylinder 11 to the release cylinder 12 through the valve hole 55a, while allowing the hydraulic fluid from the release cylinder 12 to the master cylinder 11 through the valve hole 55a. The flow of is interrupted.

  As shown in FIG. 6, the large-diameter throttle hole 53a is continuously provided in a state where the respective central axes coincide with the small-diameter throttle hole 53b when the tip of the movable valve body 57 contacts the fixed valve body 55. It is provided in the position to do. Therefore, the pressing force that urges the movable valve body 57 in the direction away from the fixed valve body 55 due to the differential pressure due to the pressure loss of the hydraulic fluid in the small diameter throttle hole 53b causes the pressure receiving surface (small diameter throttle hole of the movable valve body 57). 53b), the movable valve element 57 can slide smoothly in the inner hole 50. Further, the movable valve body 57 is urged toward the fixed valve body 55 by the elastic force of the spring 58 whose elastic force decreases when the temperature decreases. The spring 58 is made of, for example, a shape memory alloy. This shape memory alloy is an alloy having a characteristic (called a shape memory effect) that returns to its original shape when a material in a martensite state is deformed and overheated at a low temperature. For example, Ni—Ti, Cu—Zn It is an alloy in which a third element is added based on these, Cu—Al, Cu—Sn, and the like. The temperature characteristics of the spring 58 will be described later.

  Next, the detailed structure of the movable valve body 57 will be described with reference to FIG. (A) is a plane sectional view of the movable valve body 57, and (b) is a side view of the movable valve body 57. Four axial grooves 63 are provided on the outer periphery of the movable valve body 57 at equal intervals. The groove 63 is provided so as to open to the stepped portion 62 formed between the distal end portion 60 and the outer periphery of the movable valve body 57 and also to the inner hole 50.

  Therefore, when the movable valve body 57 is in contact with the fixed valve body 55, the hydraulic fluid from the release cylinder 12 passes through the port 52a through the large-diameter throttle hole 53a and the small-diameter throttle hole 53b. It returns to the master cylinder 11 from the hole 50 via the port 52b. On the other hand, when the movable valve body 57 is not in contact with the fixed valve body 55, the hydraulic fluid from the release cylinder 12 passes through the large diameter throttle hole 53a via the port 52a and passes through the groove 63 and the inner hole 50. Then, it returns to the master cylinder 11 via the port 52b. In any case, since the hydraulic fluid flows through the inner hole 50, the heat of the hydraulic fluid is sufficiently transmitted to the spring 58, and the temperature of the spring 58 and the temperature of the hydraulic fluid are substantially the same. . In particular, in the latter case, since the working fluid flows inside and outside the cylindrical wall of the movable valve body 57 by the groove 63 surrounding the spring 58, the temperature of the spring 58 and the temperature of the working fluid are better matched.

  Next, the operation of the shock torque preventing valve device 20 of the present invention will be described. First, the operation when the clutch pedal is depressed and the connection between the engine and the transmission is disconnected will be described (see FIG. 1). When the clutch pedal is depressed, the hydraulic fluid is discharged from the master cylinder 11 and flows into the port 52b of the shock torque preventing valve device 20. The air then flows from the port 52a into the release cylinder 12 through the valve hole 55a and the check valve 54 through the groove 63 of the movable valve body 57 from the inner hole 50. When the hydraulic fluid flows into the release cylinder 12, the connection between the engine and the transmission is disconnected via the output rod 12 a and the release fork 13.

  Next, an operation when the depression of the clutch pedal is released and the engine and the transmission are connected will be described. First, a case where the temperature of the hydraulic fluid is high and the elastic force of the spring 58 is sufficiently large (referred to as CASE 1) will be described. At this time, the pressing force due to the differential pressure of the hydraulic fluid received by the movable valve element 57 is smaller than the elastic force of the spring 58. Therefore, the movable valve body 57 is in contact with the fixed valve body 55 (see FIG. 1).

  When the depression of the clutch pedal is released, the release fork 13 is pushed leftward in the drawing by a return spring (not shown) of the clutch, and the piston of the release cylinder 12 is pushed in the same direction. Further, the piston of the master cylinder 11 is also returned to the initial position by a return spring (not shown). As a result, the hydraulic fluid is discharged from the release cylinder 12 and flows into the port 52a of the shock torque preventing valve device 20. Since the check valve 54 is closed and the movable valve element 57 is in contact with the fixed valve element 55, the hydraulic fluid passes through the port 52a from the large-diameter throttle hole 53a and the small-diameter throttle hole 53b. Only flows out to the port 52b (that is, receives sufficient throttling) and is returned to the master cylinder 11. Therefore, when the temperature of the hydraulic fluid is high, shock torque is reliably prevented.

  Next, since the temperature of the hydraulic fluid is low, the elastic force of the spring 58 is small, and since the actual viscosity of the hydraulic fluid is low, the pressing force due to the differential pressure is small. As a result, the elastic force of the spring 58 is reduced. Is larger than the pressing force due to the differential pressure of the working fluid in the small-diameter throttle hole (referred to as CASE 2). Also in this case, the movable valve body 57 is in contact with the fixed valve body 55 (see FIG. 1). Therefore, the operation when the depression of the clutch pedal is released and the engine and the transmission are connected is the same as in the case of CASE 1, and the hydraulic fluid is recirculated after receiving a sufficient throttle. Therefore, even when the temperature of the hydraulic fluid is low, shock torque is reliably prevented if the actual viscosity of the hydraulic fluid is low.

  Next, since the temperature of the hydraulic fluid is low, the elastic force of the spring 58 is small, and since the actual viscosity of the hydraulic fluid is high, the pressing force due to the differential pressure is large. As a result, the elastic force of the spring 58 is The case where it is smaller than the pressing force due to the differential pressure of the working fluid in the small-diameter throttle hole (referred to as CASE 3) will be described. At this time, the movable valve body 57 is separated from the fixed valve body 55 by the pressing force due to the differential pressure (see FIGS. 2 and 3).

  When the depression of the clutch pedal is released, the release fork 13 is pushed leftward in the figure by a clutch return spring (not shown), and the piston of the release cylinder 12 is pushed in the same direction. Further, the piston of the master cylinder 11 is also returned to the initial position by a return spring (not shown). As a result, the hydraulic fluid is discharged from the release cylinder 12 and flows into the port 52a of the shock torque preventing valve device 20. Since the check valve 54 is closed and the movable valve element 57 is not in contact with the fixed valve element 55, the hydraulic fluid has a step portion having a sufficient passage area from the port 52a and the large-diameter throttle hole 53a. 62 flows through the groove 63 (without much restriction) and flows out to the port 52 b and is returned to the master cylinder 11. Therefore, when the temperature of the hydraulic fluid is low and the actual viscosity of the hydraulic fluid is high, an increase in the connection time, which is the time from the release of the depression of the clutch pedal to the connection between the engine and the transmission, is prevented.

  FIG. 4 is a graph showing the relationship between the viscosity of the hydraulic fluid and the temperature. The viscosity of the hydraulic fluid increases rapidly when the temperature is below a certain temperature. This temperature is referred to herein as the viscosity change temperature. Viscosity change temperature changes with properties, such as an oil kind of a hydraulic fluid, and dirt.

  FIG. 5 is a graph showing the relationship between the temperature and the elastic force of the spring 58 formed of a shape memory alloy. The lateral elastic modulus of the spring 58 formed of the shape memory alloy rapidly decreases when the temperature is lower than a certain temperature, and as a result, the elastic force rapidly decreases. This temperature is called the transformation point. The transformation point varies depending on the composition of the spring 58, heat treatment conditions, and the like. Therefore, the elastic force of the spring 58 that urges the movable valve body 57 toward the fixed valve body 55 is greatly reduced before and after the transformation point as the temperature of the spring 58 decreases. Note that the temperature of the spring 58 substantially matches the liquid temperature of the hydraulic fluid since the spring 58 is in the hydraulic fluid path as described above.

FIG. 6 shows the difference between the viscosity of the hydraulic fluid and the pressure loss of the hydraulic fluid passing through the small diameter throttle hole 53b through the large diameter throttle hole 53a when the movable valve body 57 is in contact with the fixed valve body 55. It is explanatory drawing which shows the relationship with the pressing force which urges | biases the movable valve body 57 with a pressure. The movable valve body 57 is pressure receiving surface the difference between the cross-sectional area of the large diameter of the throttle hole ^{53a A1 (= π × d1 2} /4) and the cross-sectional area of the small-diameter throttle hole ^{53b A2 (= π × d2 2} /4) As an area of 571, a pressing force due to the differential pressure of the hydraulic fluid is received in the opposite direction to the fixed valve body 55. Here, the differential pressure of the hydraulic fluid, that is, the hydraulic pressure on the right side of the large-diameter throttle hole 53a (the inlet side of the circulating hydraulic fluid) and the left side of the small-diameter throttle hole 53b (the outlet side of the circulating hydraulic fluid). The difference from the hydraulic pressure (= differential pressure) increases as the viscosity of the hydraulic fluid increases. Therefore, the pressing force due to the differential pressure of the hydraulic fluid received by the movable valve element 57 increases as the viscosity increases.

  Further, when the pressing force due to the differential pressure received by the movable valve element 57 exceeds the elastic force that the spring 58 biases the movable valve element 57 toward the fixed valve element 55, the movable valve element 57 is separated from the fixed valve element 55. . At this time, a force due to the hydraulic pressure of the hydraulic fluid is applied to the movable valve body 57 with the difference between the cross-sectional area of the small-diameter tip 60 and the cross-sectional area A2 of the small-diameter throttle hole 53b as the area of the pressure receiving surface. Therefore, when the movable valve element 57 is separated from the state where it is in contact with the fixed valve element 55, the force due to the hydraulic pressure of the hydraulic fluid applied to the movable valve element 57 increases rapidly. Further away from the fixed valve body 55.

  FIG. 7 shows the relationship between the pressing force received by the movable valve body 57 due to the differential pressure of the hydraulic fluid, the elastic force by which the spring 58 urges the movable valve body 57 toward the fixed valve body 55, and the temperature of the hydraulic fluid. It is a graph. The pressing force FO received by the movable valve element 57 due to the differential pressure of the hydraulic fluid increases as the temperature T of the hydraulic fluid decreases. In addition, the pressure force FO differs in temperature characteristics as in FOA, FOB, and FOC when the type of hydraulic fluid is different or when the properties of liquid such as dirt are different. Here, the hydraulic fluids showing the temperature characteristics of FOA, FOB, and FOC are referred to as hydraulic fluid A, hydraulic fluid B, and hydraulic fluid C, respectively.

  On the other hand, the elastic force FS that the spring 58 urges the movable valve body 57 toward the fixed valve body 55 side has the temperature of the spring 58 substantially coincides with the temperature T of the hydraulic fluid. Decrease. Accordingly, the temperatures (herein referred to as critical temperatures) between the CASE 2 and the CASE 3 are the temperatures TA, TB, TC of the intersections CA, CB, CC of the curves FOA, FOB, FOC and the curve FO. That is, the critical temperature becomes high in a hydraulic fluid having a high viscosity. For example, the critical temperature TB is −5 ° C.

  Further, when the hydraulic fluid is higher than the critical temperature, the state of CASE1 or CASE2 is set, and the clutch connection time is determined based on the volume of the hydraulic chamber (not shown) of the release cylinder 12, the cross-sectional area of the small-diameter throttle hole 53b, Determined by the viscosity. The cross-sectional area of the small-diameter throttle hole 53b is set so that the engagement time of the clutch does not cause torque shock and does not deteriorate operability.

  When the hydraulic fluid is lower than the critical temperature, the state of CASE 3 is established, and the clutch connection time depends on the capacity of the hydraulic chamber (not shown) of the release cylinder 12, the cross-sectional area of the large-diameter throttle hole 53a, and the viscosity of the hydraulic fluid. It is determined. The cross-sectional area of the large-diameter throttle hole 53a is set so that the engagement time of the clutch does not generate torque shock and does not degrade operability.

  Accordingly, the critical temperature becomes high in the hydraulic fluid having a high viscosity like the hydraulic fluid A (= the maximum temperature of the hydraulic fluid in the CASE 3 state becomes high), and the hydraulic fluid having a low viscosity like the hydraulic fluid C is used. The critical temperature is lowered (= the maximum temperature of the hydraulic fluid that is in the state of CASE 3 is lowered). In other words, the timing for switching the throttle hole is determined not only by the temperature of the hydraulic fluid but also by the actual viscosity of the hydraulic fluid. Change of the connection time, which is the time from the release of the depression of the clutch pedal to the connection between the engine and the transmission, is suppressed.

  In addition, this invention can take the following forms.

  (A) In the present embodiment, the case where the movable valve body is urged in the direction of the fixed valve body by one spring has been described, but the spring urged in the direction in which the movable valve body approaches the fixed valve body And a spring biased in a direction away from the fixed valve body. In this case, by adjusting the spring constants of the two springs, the viscosity of the hydraulic fluid that switches the throttle hole can be adjusted. In this case, at least one of the two springs may be a spring made of a shape memory alloy. In this case, it is possible to adjust the temperature and viscosity of the hydraulic fluid to which the throttle hole is switched by adjusting the spring constants and transformation points of the two springs.

  (B) In this embodiment, the case where the check valve is provided on the fixed valve body has been described. However, on the passage other than the passage through the small-diameter throttle hole or the large-diameter throttle hole of the hydraulic fluid. In other words, it may be arranged on the hydraulic fluid passage between the master cylinder and the release cylinder separately from the shock torque preventing valve device. In the latter case, the structure of the shock torque preventing valve device is simplified.

It is a front sectional view of the valve device for shock torque prevention to which the present invention is applied (the state in which the movable valve body and the fixed valve body are in contact). It is front sectional drawing of the valve apparatus for shock torque prevention to which this invention is applied (state in which the movable valve body and the fixed valve body are separated). It is the plane sectional view and side view of a movable valve body. It is a graph which shows the relationship between the viscosity of a hydraulic fluid, and temperature. It is a graph which shows the relationship between the temperature and elastic force of the spring formed with the shape memory alloy. It is sectional drawing which shows the throttle-hole vicinity part of the said movable valve body and a fixed valve body. It is a graph which shows the relationship between the pressing force which a movable valve body receives with the differential pressure | voltage of a hydraulic fluid, the elastic force which a spring urges | biases a movable valve body to the fixed valve body side, and the temperature of hydraulic fluid. It is front sectional drawing of the conventional shock torque prevention valve (a state in which the valve member exists in the position which does not interrupt | block the 1st chamber and the 2nd chamber). It is a front sectional view of the conventional shock torque prevention valve (the state in which the valve member is in the position which intercepts the 1st room and the 2nd room).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Clutch pedal 11 Master cylinder 12 Release cylinder 20 Shock torque prevention valve device 50 Inner hole 52a, 52b Port 54 Check valve 55 Fixed valve body 57 Movable valve body 58 Spring 62 Step part

Claims (4)

  It is arranged on the hydraulic fluid passage between the master cylinder operated by the clutch pedal and the release cylinder that moves the clutch by the hydraulic pressure of the hydraulic fluid, and restricts the flow rate of the hydraulic fluid flowing back from the release cylinder to the master cylinder. A shock torque preventing valve device for preventing shock torque of the clutch by having a valve body having an inner hole and a large-diameter throttle hole for restricting a flow of hydraulic fluid and a fixed valve body; A movable valve body having a small-diameter restricting hole for restricting the flow, and slidably housed in an inner hole of the valve body in a direction to be separated from and in contact with the fixed valve body; and the movable valve body by elastic force. A spring that urges in a direction approaching the fixed valve body and decreases the elastic force when the temperature is lowered, and is moved forward by a differential pressure due to a pressure loss of hydraulic fluid in the small-diameter throttle hole. When a pressing force is applied to urge the movable valve body away from the fixed valve body, and the elastic force is greater than the pressing force, the movable valve body comes into contact with the fixed valve body, so that the passage of the hydraulic fluid is When the elastic force is smaller than the pressing force, the movable valve body is separated from the fixed valve body and the working fluid flows through the gap when the elastic force is smaller than the pressing force. The working fluid flows through the large-diameter throttle hole. A valve device for preventing shock torque of a clutch, wherein the valve is configured to be limited.   2. The pressing force by the differential pressure acts on the movable valve body with a difference between a cross-sectional area of the large-diameter throttle hole and a cross-sectional area of the small-diameter throttle hole as a pressure receiving area. Valve device for preventing shock torque of clutch.   A passage of hydraulic fluid from the master cylinder to the release cylinder, on a passage other than a passage through which the hydraulic fluid passes through the small-diameter throttle hole or the large-diameter throttle hole, the master cylinder to the release cylinder. The clutch shock according to claim 1 or 2, further comprising a check valve that allows the flow of the hydraulic fluid and blocks the flow of the hydraulic fluid from the release cylinder to the master cylinder. Torque prevention valve device.   The valve device for shock torque prevention of a clutch according to any one of claims 1 to 3, wherein the spring is made of a shape memory alloy.

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