Clutch device

Abstract

To appropriately control a flow rate of oil in an oil flow passage when a clutch pedal is stepped back.SOLUTION: A clutch device includes a clutch master cylinder, a clutch release cylinder and an oil flow passage 25. The oil flow passage 25 has: a small diameter part 251; and a large diameter part 252 which is arranged in a homeward direction X2 than the small diameter part 251, and has a diameter larger than that of the small diameter part 251. The large diameter part 252 is provided with a flow rate changing mechanism 30. The flow rate changing mechanism 30 includes: an orifice member 32 in which a through hole 32a through which oil passes is formed and which is displaceable in the homeward direction X2 and an outward direction X1; and a spring 35 which energizes the orifice member 32 in the outward direction X1. An external diameter of the orifice member 32 is smaller than a diameter of the large diameter part 252, and larger than a diameter of the small diameter part 251.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a clutch device to be mounted on a vehicle. [Background technology]

[0002] Patent Document 1 discloses an example of a clutch device that operates a clutch located between a vehicle engine and a transmission mechanism. The clutch device includes a flow rate varying device provided in an oil flow path connected to a clutch master cylinder and a clutch release cylinder. The flow path varying device includes a clutch return path through which oil flows from the clutch release cylinder to the clutch master cylinder when the clutch pedal is released. A solenoid valve is provided in the clutch return path to vary the flow rate of oil in the clutch return path. Therefore, in this clutch device, the flow rate of oil in the clutch return path is adjusted by controlling the solenoid valve with a control unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-121626 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described clutch device, the flow rate of oil in the clutch return path is adjusted based on instructions from the control unit. Therefore, if the control unit issues a delayed instruction or an incorrect instruction, the flow rate of oil in the clutch return path may not be adjusted appropriately. [Means for solving the problem]

[0005] A clutch device for solving the above problem interrupts power transmission through the clutch by causing oil to flow through an oil passage in a forward direction, i.e., from a clutch master cylinder toward a clutch release cylinder, when the clutch pedal is depressed. On the other hand, when the clutch pedal is released, oil flows through the oil passage in a return direction, i.e., the opposite direction to the forward direction, allowing power transmission through the clutch. In this clutch device, the oil passage has a small diameter portion and a large diameter portion that is positioned further in the return direction than the small diameter portion and has a larger diameter than the small diameter portion. The large diameter portion is provided with a flow rate variable mechanism that adjusts the flow rate of oil through the oil passage. The flow rate variable mechanism includes an orifice member that has a through hole formed therein through which oil passes and is displaceable in the return direction and the forward direction, and a spring that biases the orifice member in the forward direction. The outer diameter of the orifice member is smaller than the diameter of the large diameter portion and larger than the diameter of the small diameter portion. [Effects of the Invention]

[0006] The above-described clutch device has the advantage of being able to appropriately control the flow rate of oil in the oil flow path when the clutch pedal is released. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a clutch device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing an outline of a flow rate varying mechanism provided in the clutch device of FIG. [Figure 3] FIG. 3 is a cross-sectional view showing an outline of the flow rate varying mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, one embodiment of a clutch device mounted on a vehicle will be described with reference to FIGS. 1, the clutch device 20 includes a clutch 21 disposed in a power transmission path from the engine 11 to the transmission mechanism 12. When a clutch pedal 22 is depressed, the clutch device 20 interrupts the transmission of power from the engine 11 to the transmission mechanism 12 via the clutch 21. On the other hand, when the clutch pedal 22 is not depressed, the clutch device 20 allows the transmission of power from the engine 11 to the transmission mechanism 12 via the clutch 21.

[0009] The clutch device 20 includes a clutch master cylinder 23 to which the clutch pedal 22 is connected, a clutch release cylinder 24, and an oil flow path 25. The oil flow path 25 is an oil flow path connecting the clutch master cylinder 23 and the clutch release cylinder 24. When the clutch pedal 22 is depressed, hydraulic pressure is generated in the clutch master cylinder 23, causing oil to flow through the oil flow path 25 from the clutch master cylinder 23 to the clutch release cylinder 24. This increases the hydraulic pressure in the clutch release cylinder 24, which activates the clutch release cylinder 24 to release the clutch 21. This interrupts power transmission through the clutch 21. On the other hand, when the clutch pedal 22 is released, the hydraulic pressure in the clutch master cylinder 23 decreases. This causes oil to flow through the oil flow path 25 from the clutch release cylinder 24 to the clutch master cylinder 23. This decreases the hydraulic pressure in the clutch release cylinder 24, which activates the clutch release cylinder 24 to engage the clutch 21. This allows power transmission via the clutch 21.

[0010] Hereinafter, the direction of oil flow in the oil flow path 25 when the clutch pedal 22 is depressed will be referred to as the "forward direction X1." The direction of oil flow in the oil flow path 25 when the clutch pedal 22 is released will be referred to as the "return direction X2." The return direction X2 is the opposite direction of the forward direction X1.

[0011] 1, 2, and 3, the oil flow path 25 is provided with a flow rate varying mechanism 30 that adjusts the flow rate of oil flowing through the oil flow path 25 in the return direction X2 when the clutch pedal 22 is released. The flow rate varying mechanism 30 operates so that the flow rate of oil decreases as the operating speed when the clutch pedal 22 is released increases.

[0012] 2 and 3, the oil flow path 25 is provided with a small diameter portion 251 and a large diameter portion 252 that is disposed further in the return direction X2 than the small diameter portion 251. The diameter of the large diameter portion 252 is larger than the diameter of the small diameter portion 251. The flow rate varying mechanism 30 is disposed in the large diameter portion 252.

[0013] The flow rate varying mechanism 30 includes a cylindrical bushing 31, an orifice member 32 located further in the forward direction X1 than the bushing 31, and a spring 35 located between the bushing 31 and the orifice member 32. The bushing 31 is cylindrical and is installed in an immovable state in the oil flow path 25. The orifice member 32 is installed in the oil flow path 25 and is movable in the backward direction X2 and the forward direction X1. The spring 35 is supported by the bushing 31 and biases the orifice member 32 in the forward direction X1.

[0014] The orifice member 32 has a cylindrical portion 33 and a bottom wall 34 that closes the opening of the cylindrical portion 33 on the backward direction X2 side. The orifice member 32 is arranged so that the axis of the cylindrical portion 33 roughly coincides with the axis of the oil flow path 25. A through hole 32a through which oil passes is provided in the bottom wall 34. The outer diameter of the cylindrical portion 33 is smaller than the diameter of the large diameter portion 252 and larger than the diameter of the small diameter portion 251.

[0015] When the clutch pedal 22 is depressed and oil flows through the oil flow path 25 in the forward direction X1, the orifice member 32 is pressed against the boundary portion 253 between the large diameter portion 252 and the small diameter portion 251 by the biasing force of the spring 35, as shown in Figure 3. As a result, the oil discharged from the clutch master cylinder 23 into the oil flow path 25 passes through the through hole 32a and is supplied to the clutch release cylinder 24.

[0016] On the other hand, when the clutch pedal 22 is released, oil flows in the return direction X2 through the oil flow path 25. In this case, the position of the orifice member 32 changes depending on the flow rate, i.e., the flow velocity, of the oil flowing through the oil flow path 25 in the return direction X2.

[0017] The oil pressure in the oil flow path 25 is referred to as the "flow path oil pressure Po." The flow path oil pressure Po varies depending on the flow rate (i.e., flow velocity) of oil in the oil flow path 25. According to Bernoulli's theorem, the greater the flow rate, the lower the flow path oil pressure Po. The lower the flow path oil pressure Po, the smaller the load D applied to the orifice member 32 from the oil flowing in the backward direction X2. The load D acts on the orifice member 32 in the backward direction X2. The orifice member 32 is located at a position where the load D and the restoring force of the spring 35 are balanced. In other words, when the load D is greater than the restoring force of the spring 35, the orifice member 32 moves in the backward direction X2. On the other hand, when the load D is smaller than the restoring force of the spring 35, the orifice member 32 moves in the forward direction X1.

[0018] Therefore, a "boundary speed" is set as a criterion for determining whether the operating speed when the clutch pedal 22 is released is large, and a load D corresponding to the boundary speed is set as a "reference load DB." At this time, a spring whose spring load has the same magnitude as the reference load DB is adopted as the spring 35.

[0019] The operation and effects of this embodiment will be described. When the clutch pedal 22 is released at a relatively slow operating speed, the flow rate of oil flowing through the oil flow passage 25 in the return direction X2 is also relatively small. As such, the smaller the oil flow rate, the higher the flow passage oil pressure Po. At this time, if the operating speed is slower than the boundary speed, the load D applied to the orifice member 32 by the oil flowing in the return direction X2 becomes greater than the spring load of the spring 35. As a result, as shown in FIG. 2 , the orifice member 32 moves in the return direction X2 against the force input from the spring 35. That is, the orifice member 32 moves away from the boundary portion 253. Then, as shown by the arrows in FIG. 2 , oil flows not only through the through hole 32a of the orifice member 32 but also through the gap between the orifice member 32 and the peripheral wall of the large-diameter portion 252. That is, the flow passage cross-sectional area is larger than when the orifice member 32 is pressed against the boundary portion 253. This stabilizes the return speed of the clutch pedal 22.

[0020] On the other hand, when the clutch pedal 22 is released at a relatively high operating speed, the flow rate of oil flowing through the oil flow passage 25 in the return direction X2 is also relatively high. As such, the flow passage oil pressure Po decreases as the oil flow rate increases. At this time, if the operating speed is greater than the boundary speed, the load D applied to the orifice member 32 by the oil flowing in the return direction X2 becomes smaller than the spring load of the spring 35. As a result, as shown in FIG. 3 , the force input from the spring 35 presses the orifice member 32 against the boundary portion 253. In this case, as shown by the arrows in FIG. 3 , although oil flows through the through hole 32a of the orifice member 32, oil does not flow between the orifice member 32 and the peripheral wall of the large-diameter portion 252. This causes the oil pressure in the clutch release cylinder 24 to decrease relatively gradually. As a result, premature engagement of the clutch 21 and sudden acceleration of the vehicle are suppressed. This suppresses an increase in the load on the components of the clutch 21 and the transmission mechanism 12.

[0021] If the operating speed when clutch pedal 22 is released is high, the amount of oil flowing through oil flow path 25 tends to be large. If the oil flow rate is large, the oil pressure in clutch release cylinder 24 decreases at a faster rate. If clutch 21 is engaged early and the vehicle starts moving suddenly, the load on the components of clutch 21 and transmission mechanism 12 increases.

[0022] In this regard, in the above-described clutch device 20, when the operating speed when the clutch pedal 22 is released is high, the flow rate variable mechanism 30 operates to reduce the flow rate of oil flowing through the oil passage 25. This reduces the rate at which the oil pressure in the clutch release cylinder 24 decreases, thereby preventing the clutch 21 from engaging prematurely and causing the vehicle to suddenly start moving, and ultimately preventing an increase in the load on the components of the clutch 21 and the transmission mechanism 12. On the other hand, when the operating speed is low, the flow rate variable mechanism 30 operates to prevent the flow rate of oil flowing through the oil passage 25 from decreasing. This makes it possible to stabilize the release speed of the clutch pedal 22.

[0023] Therefore, the clutch device 20 can appropriately control the flow rate of oil in the oil flow path 25 when the clutch pedal 22 is released. [Explanation of symbols]

[0024] 20...clutch device, 21...clutch, 22...clutch pedal, 23...clutch master cylinder, 24...clutch release cylinder, 25...oil flow path, 251...small diameter portion, 252...large diameter portion, 30...flow rate variable mechanism, 32...orifice member, 32a...through hole, 35...spring.

Claims

[Claim 1] When a clutch pedal is depressed, oil flows through an oil flow passage in a forward direction, which is a direction from a clutch master cylinder to a clutch release cylinder, thereby interrupting power transmission through the clutch, and when the clutch pedal is released, oil flows through the oil flow passage in a return direction, which is the opposite direction to the forward direction, thereby allowing power transmission through the clutch. the oil flow path has a small diameter portion and a large diameter portion that is disposed in the return direction relative to the small diameter portion and has a diameter larger than that of the small diameter portion, a flow rate varying mechanism that adjusts the flow rate of oil in the oil flow path is provided in the large diameter portion, the flow rate varying mechanism includes an orifice member having a through hole formed therein through which oil passes and being displaceable in the backward direction and the forward direction, and a spring that biases the orifice member in the forward direction, The outer diameter of the orifice member is smaller than the diameter of the large diameter portion and larger than the diameter of the small diameter portion. A clutch device characterized by:

Images