JPH01300025A - Cam shaft phase adjusting device - Google Patents

Abstract

PURPOSE:To reduce the size of the device by constituting a slider equipped with helical- spline-internal gears engaged with helical-spline-external gears, which are attached to two sleeves arranged on a same shaft and which are inclined to the reverse directions with each other, in such a manner that the slider is displaced by means of a hydraulic driving mechanism having a predetermined structure. CONSTITUTION:A shaft phase adjusting device attached to a cam shaft 10 that is used to drive a fuel injection pump is provided with a first sleeve 20 which is fixed to a cam shaft gear 15 and equipped with a helical-spline-external gear, a second sleeve 20 equipped with a helical-spline-external-gear whose dentition is inclined symmetrically with that of the said gear of the first sleeve, and a slider 34 equipped with helical-spline-internal-gears engaged with the above-mentioned two externag ears respectively, and the slider 34 is shifted by a hydraulic driving mechanism 17. In this case, an annular piston chamber 45 is formed in a piston guide 40 of the hydraulic driving mechanism 17, so that the left-end 46 of the second sleeve 24 is inserted into the inside of the chamber 45. In addition, an annular working piston 41, whose end- surface 52 is press-fitted to the slider 34, is inserted to the space between this left-end part 46 and an external wall 44 of the piston guide 40.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for adjusting the phase of a camshaft of an internal combustion engine, such as a camshaft of a diesel engine, with respect to a crankshaft using hydraulic pressure. .

(Prior art and its problems) This type of camshaft phase adjustment device is used to adjust the opening and closing timing of the intake and exhaust valves for gasoline engines, and the opening and closing timing of the intake and exhaust valves and the fuel injection timing for diesel engines. It is already known that it is possible to adjust the

However, there is room for improvement in that the hydraulic drive mechanism that generates the hydraulic pressure for adjusting the camshaft phase is complicated and the entire device becomes larger.

Related prior art includes Japanese Patent Application Laid-Open No. 54-52218, Japanese Utility Model Application No. 55-163535, and Japanese Utility Model Application No. 5.6-860.
No. 37, Japanese Patent Application Publication No. Sho Go-243308, Utility Model Publication No. Sho 61-2
There are issues such as No. 1808.

(Objective of the Invention) An object of the present invention is to provide a camshaft phase adjustment device that is equipped with a hydraulic drive mechanism that has a simple structure and that can reduce the size of the entire device.

(Structure of the Invention) (1) Technical Means The present invention provides a substantially cylindrical first sleeve that is fixed to a camshaft gear of an internal combustion engine and has first helical spline external teeth on its outer peripheral surface, and a first sleeve that is coaxial with the first sleeve. placed adjacent to the top;
a second sleeve having second helical spline external teeth on the outer circumferential surface with a tooth row tilted symmetrically with the first helical spline external teeth; and a substantially cylindrical sleeve having helical spline internal teeth meshing with both of the helical spline external teeth. In a camshaft phase adjustment device that includes a slider and a hydraulic drive mechanism that slides the slider in the axial direction using hydraulic pressure, a cylindrical portion of a piston guide of the hydraulic drive mechanism is fixed inside the second sleeve. , a substantially annular piston chamber is formed at the end of the piston guide opposite to the first sleeve, the end of the second sleeve opposite to the first sleeve extends into this piston chamber, and the end opposite to the first sleeve and the An annular actuating piston for driving the slider is fitted between the outer wall of the piston chamber so as to be slidable in the axial direction, and an outer guide surface on which the outer peripheral surface of the actuating piston slides is formed on the inner surface of the outer wall. , an inner guide surface on which the inner circumferential surface of the working piston slides is formed on the outer surface of the end opposite to the first sleeve; This camshaft phase adjustment device is characterized in that a portion thereof is cut out to form a hydraulic oil passage through which hydraulic oil flows into a piston chamber.

(2) Since the end on the side opposite to the first sleeve extends into the screw chamber, and the actuating piston is disposed between the end on the side opposite to the first sleeve and the outer wall of the piston chamber, the axial direction of the hydraulic drive mechanism Short in length.

Since the hydraulic oil passage is formed between the second sleeve and the piston guide, the hydraulic drive mechanism can also be made smaller in the radial direction.

(Example) FIG. 1 shows a camshaft phase adjustment device adopting the present invention.
10 is a camshaft of a diesel engine.

A camshaft 10 is used to drive a plunger of a fuel injection pump (not shown) using a cam 11.

The camshaft 10 is a camshaft metal 12 and a cylinder block 13
It is pivoted on. A gear case 14 is fixed to the left end surface of the cylinder block 13 in the drawing, and a camshaft gear 15 is provided within the gear case 14.

Further, a flywheel housing 16 is fixed to the left end surface of the gear case 14.
A camshaft phase adjustment device and a flywheel 18 are provided within the camshaft 6. Reference numeral 18a is a ring gear.

A substantially cylindrical first sleeve 20 is fixed to the camshaft gear 15 concentrically with the camshaft 10 with a parallel pin 21 and a bolt 22, and a first helical brine 23 extending downward to the right is provided on the outer peripheral surface of the first sleeve 20. It is formed. This first sleeve 2
A substantially cylindrical second sleeve 24 is rotatably fitted to the first sleeve 20 at a boss portion 25 adjacent to the left side of the second sleeve 24. A second helical force bline 26 symmetrical to the helical spline 23 and downward to the left is formed.

The boss portion 25 of the second sleeve 24 extends rightward toward the journal portion 28 of the camshaft 10 and is fixed to the journal portion 28 with a bolt 29. A boss portion 30 of the camshaft gear 15 is rotatably fitted onto the outer peripheral surface of the boss portion 25, and a thrust plate 33 is interposed between an end surface 31 of the boss portion 30 and an end surface 32 of the journal portion 28. It is. This thrust plate 33 is fixed to the cylinder block 13 with a plurality of bolts 33a. Further, a C-shaped retaining ring 30a is fitted onto the outer circumferential surface of the boss portion 30, and positions the first sleeve 20 in the axial direction while allowing rotation thereof.

A substantially cylindrical slider 34 is fitted to the radial outer peripheries of the first sleeve 20 and the second sleeve 24 so as to be slidable in the axial direction, that is, in the left and right directions in the drawing. On the inner surface of the slider 34, helical spline internal teeth 23a that mesh with the first helical spline 23 and helical spline internal teeth 26a that mesh with the second helical spline 26 are formed.

A compression coil spring 36 is compressed between the flange 35 of the slider 34 and the first sleeve 20, and the spring force of the compression coil spring 36 biases the slider 34 in the direction of arrow A. The hydraulic drive mechanism 17 generates hydraulic pressure that pushes the slider 34 in the reverse A direction, and the slider 34
The phase between the camshaft gear 15 and the camshaft 10 is adjusted by sliding left and right.

The camshaft gear 15 is interlocked with a crankshaft (not shown) of the engine body through idle gears 37 and 38, extracts power from the crankshaft, and sequentially moves the first sleeve 20, slider 34, and second sleeve 24. , the rotational force is transmitted to the camshaft 1o via the bolt 29. therefore,
The first sleeve 20 and the second sleeve 24 with the slider 34
By changing the phase of camshaft gear 15 and camshaft 1
0 phase can be adjusted.

The hydraulic drive mechanism 17 that pushes the slider 34 in the reverse A direction and slides the slider 34 left and right is formed of a piston guide 40, an operating piston 41, and the like. The piston guide 40 has an inner cylindrical portion 42 connected to the second sleeve 24.
The left end portion of the cylindrical portion 42 is integrally formed with a bottom wall 43 extending outward in the radial direction and an outer portion 944 extending left and right approximately parallel to the cylindrical portion 42 . Bottom wall 43, outer wall 44
has a continuous annular shape over the entire circumference, and forms an annular piston chamber 45 inside. The left end of the second sleeve 24 extends into the piston chamber 45 to form a substantially cylindrical left end 46 (end on the side opposite to the first sleeve). A male thread 47 is formed on the outer circumferential surface of the cylindrical portion 42 of the piston guide 400, and this male thread 47 is screwed into a female thread 48 on the inner circumferential surface of the second sleeve 24, and is fitted into a spigot portion 49 on the inner circumferential surface of the left end portion 46. At the same time, the cylindrical portion 42 is fixed to the second sleeve 24. The means for fixing both is a male screw 47 and a female screw 4.
8 and the spigot part 49, other means such as press-fitting may be used.

The annular operating piston 41 is fitted between the left end portion 46 and the outer wall 44 so as to be slidable left and right. The actuating piston 41 is slidably fitted on both sides of an outer guide surface 50 of the outer wall 44 and an inner guide surface 51 of the left end portion 46 in a fluid-tight manner. An end surface 52 of the actuating piston 41 is in pressure contact with a flange 35 of the slider 34. A hydraulic oil passage 53 through which hydraulic oil flows to the piston chamber 45 is formed between the cylindrical portion 42 and the second sleeve 24. This hydraulic oil passage 53
As shown in the figure, a part of the male thread 47 of the cylindrical portion 42 is cut out to communicate the oil chamber 54 and the piston chamber 45 in FIG. 1. Note that the hydraulic oil passage is not limited to the case where the male thread 47 is cut out, but a part of the female thread 48 may be cut out, or both the male thread 47 and the female thread 48 may be formed. In addition to the groove-shaped passage 53, the half-moon-shaped passage 53a
It can also be done.

A substantially cylindrical check valve guide 57 is fitted inside the cylindrical portion 42 via a bush 56 . The left end of the check valve guide 57 is screwed into a retainer 60 fixed to the flywheel housing 16.

The hydraulic oil vibro 1 is connected to the retainer 60, and the passage 62
A portion of the lubricating oil is sent as hydraulic oil to the

A communication hole 63 communicating with a passage 62 passes through the center of the check valve guide 57, and a valve seat 64 is formed in the middle of the communication hole 63. A check valve 65 is provided on the valve seat 64 so as to be openable and closable. The check valve 65 is biased in the closing direction by a valve spring 66, and the valve spring 66 is held by a cap 67.

A communication hole 68 communicating with the oil chamber 54 is bored in the cap 67 . The cap 67 is screwed onto the check valve guide 57.

A hydraulic oil relief hole 70 that penetrates the check valve guide 57 in the radial direction is bored in a portion of the circulation hole 63 closer to the oil chamber 54 than the valve seat 64. is discharged into the engine's oil pan. The position of the hydraulic oil relief hole 70 is such that it is open when the check valve 65 in FIG.
When the check valve 65 shown in the figure is open, the check valve 65 is set in a closed position.

Next, the distribution route of lubricating oil will be explained. The cylinder block 13 in FIG. 1 is formed with a passage 71 through which lubricating oil from the engine body flows. This passage 71 leads to a passage 72 of the camshaft 10, which in turn communicates with passages 73, 74, 75. The left end of the passage 73 is sealed with a plug 76. The female thread 77 into which the bolt 29 is screwed is formed over a range Ll, and the passage 75 is connected to a portion of the bolt hole 78 where the female thread 77 is not formed. Therefore, the lubricating oil supplied from the passage 75 flows through the gap between the bolt 29 and the bolt hole 78. A passage 79 is opened at the outer periphery of the bolt hole 78.
9 to the sliding end surface 31 of the thrust plate 33.
This structure supplies lubricating oil to 32.

A passage 80 communicates with the center portion of the bolt hole 78 in the left-right direction, and the passage 80 communicates with an oil groove 81. Lubricating oil is supplied from the oil groove 81 to the sliding surface 82 between the camshaft gear 15 and the boss portion 25. A passage 83 communicates with the left end of the bolt hole 78, and the passage 83 extends from the oil groove 84 to the boss portion 25.
The lubricating oil is sent to the outer surface 25a of.

In the above configuration, no hydraulic oil is supplied to the passage 62 during startup or in a steady state, and the check valve 65 is pressed against the valve seat 64 and closed. Therefore, the oil chamber 54 and the piston chamber 45
No hydraulic oil flows into the slider 34, and the slider 34 is pushed to the leftmost end by the spring force of the compression coil spring 36.

From the state shown in FIG. 1, when the hydraulic oil is supplied to the passage 62 and the angle is retarded, as shown in FIG. It slides in the A direction, moves away from the valve seat 64, and the check valve 65 opens. When the check valve 65 opens, the hydraulic oil relief hole 70 is closed, and the hydraulic oil flows from the flow hole 63 into the oil chamber 54, and further flows into the piston chamber 45 through the hydraulic oil passage 53.

When the hydraulic oil flows into the piston chamber 45, the working piston 4
Hydraulic pressure in the opposite A direction of 1 is generated, and the actuating piston 41 moves against the spring force of the compression coil spring 36 to move the slider 3.
Push 4 in the reverse A direction. When the slider 34 slides in the reverse A direction, the first helical spline 23 and the second helical spline 26 cause the first sleeve 20 and the second sleeve 24 to rotate relative to each other, and as described above, the camshaft gear 1
5 and the phase of the camshaft 10 change.

When returning from the state shown in FIG. 3 to the state shown in FIG.
When the hydraulic oil supply from the valve stops, the check valve 65 closes to the valve seat 64.
Sit down and close the valve. When the check valve 65 is in the closed state shown in FIG.
3. The hydraulic oil passes sequentially through the oil chamber 54 and the circulation hole 63 and is discharged from the hydraulic oil relief hole 70. Therefore, when the supply of hydraulic oil to the passage 62 is stopped, the working piston 41 rapidly returns from the position shown in FIG. 3 to the position shown in FIG. Return to phase.

In the hydraulic drive mechanism 17, the left end portion 46 extends within the outer wall 44, and the operating piston 41 is provided between the left end portion 46 and the outer wall 44, so the hydraulic drive mechanism 17 is short in the axial direction. Furthermore,
Since the hydraulic oil passage 53 is formed between the second sleeve 24 and the cylindrical portion 42, the hydraulic drive mechanism 17 is also made smaller in the radial direction.

Although the hydraulic oil supply to the passage 62 is stopped, the piston chamber 45
The hydraulic oil in the piston chamber 45, the hydraulic oil passage 53,
The hydraulic oil passes through the oil chamber 54 and the circulation hole 63 and is rapidly discharged from the hydraulic oil relief hole 70, and the hydraulic pressure of the hydraulic piston 41 disappears in a short time. Therefore, the phase between the camshaft gear 15 and the camshaft 10 quickly returns to its original state, and the response of the phase control is good.

(Effects of the Invention) As explained above, in the first claim of the present invention, the left end portion 46 (end portion on the side opposite to the first sleeve) extends within the outer wall 44 of the hydraulic drive mechanism 17, and the left end portion 46 and the outer wall 44 Since the actuating piston 41 is provided between them, the hydraulic drive mechanism 17 can be shortened in the axial direction. Furthermore, since the hydraulic oil passage 53 is formed between the second sleeve 24 and the cylindrical portion 42, the hydraulic drive mechanism 17 can be made smaller in the radial direction as well.

Next, in the second claim, a check valve 65 for preventing backflow of hydraulic oil is provided on a valve seat 64 formed in the middle of the flow hole 63 of the check valve guide 57, and the check valve 65 of the flow hole 63 A hydraulic oil relief hole 70 is formed that communicates with a position closer to the oil chamber 54 and passes through the check valve guide 57 in a direction intersecting the axial direction. The check valve 65 is closed when the check valve 65 is open and moves away from the valve seat 64, and opens into the flow hole 63 when the check valve 65 is closed and comes into pressure contact with the valve seat 64. When the hydraulic oil supply is stopped, the hydraulic oil in the piston chamber 45 can sequentially pass through the piston chamber 45, the hydraulic oil passage 53, the oil chamber 54, and the circulation hole 63, and be rapidly discharged from the hydraulic oil relief hole 70. The phase between the gear 15 and the camshaft 10 can be quickly returned to the original state, and the responsiveness of phase control can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the camshaft phase adjustment device of the present invention;
FIG. 2 is a schematic view taken in the direction of arrow (■) in FIG. 1, and FIG. 3 is a longitudinal cross-sectional view showing a state in which the phase has been adjusted. 10... camshaft, 15.
...Camshaft gear, 20...First sleeve, 24...
Second sleeve, 34...Slider, 36...Compression coil spring, 17...Hydraulic drive mechanism, 41...
・Operating piston, 53... Hydraulic oil passage, 65... Check valve, 70... Hydraulic oil relief hole Patent applicant: Yanmar Diesel Co., Ltd. Agent Patent attorney: Tadataka Omori

Claims (2)

[Claims] (1) It is fixed to the camshaft gear of the internal combustion engine, and the first
a substantially cylindrical first sleeve having helical spline external teeth; and a second helical spline disposed coaxially and adjacent to the first sleeve and having a tooth row inclined symmetrically with the first helical spline external teeth on the outer peripheral surface. A second sleeve having external teeth, a substantially cylindrical slider having internal helical spline teeth that mesh with both of the external helical spline teeth, and a hydraulic drive mechanism that slides the slider in the axial direction using hydraulic pressure. In the camshaft phase adjustment device, a cylindrical portion of a piston guide of the hydraulic drive mechanism is fixed inside the second sleeve, and a substantially annular piston chamber is formed at an end of the piston guide on the side opposite to the first sleeve; An end of the second sleeve opposite to the first sleeve is extended into the piston chamber, and an annular operating piston that drives the slider is inserted between the end of the second sleeve opposite to the first sleeve and the outer wall of the piston chamber in the axial direction. An outer guide surface that is slidably fitted and on which the outer circumferential surface of the actuating piston slides is formed on the inner surface of the outer wall, and an inner guide surface on which the inner circumferential surface of the actuating piston slides is formed on the opposite end of the first sleeve. A hydraulic oil passage is formed between the second sleeve and the cylindrical part of the piston guide by cutting out a part of both or one of them to flow hydraulic oil into the piston chamber. camshaft phase adjustment device. (2) A substantially cylindrical check valve guide is provided inside the cylindrical part of the piston guide so as to be rotatable with respect to the cylindrical part, and a communication hole passes through the check valve guide in the axial direction and communicates with the hydraulic oil passage. A check valve for preventing the backflow of hydraulic oil is provided on a valve seat formed in the middle of this communication hole, and a check valve guide is provided in communication with a position on the oil chamber side of the check valve of the communication hole. A hydraulic oil relief hole is formed that passes through the hydraulic oil relief hole in a direction intersecting the axial direction, and when the check valve opens away from the valve seat, the opening on the flow hole side of the hydraulic oil relief hole is closed by a reverse upward valve, and the reverse side is closed. Claim 1: The stop valve is formed to open into the flow hole when the valve is closed and comes into pressure contact with the valve seat.
The camshaft phase adjustment device described in .